Impact of Procedure Volume on the Outcomes of Surgical Aortic Valve Replacement

BACKGROUND

 Literature demonstrated that procedure volumes affect outcomes of patients undergoing transcatheter aortic valve implantation. We evaluated the outcomes of surgical aortic valve replacement.

METHODS

 All isolated surgical aortic valve replacement procedures in Germany in 2017 were identified. Hospitals were divided into five groups from ≤25 (very low volume) until >100 (very high volume) annual procedures.

RESULTS

 In 2017, 5,533 patients underwent isolated surgical aortic valve replacement. All groups were of comparable risk (logistic EuroSCORE, 5.12-4.80%) and age (66.6-68.1 years). In-hospital mortality and complication rates were lowest in the very high-volume group. Multivariable logistic regression analyses showed no significant volume-outcome relationship for in-hospital mortality, stroke, postoperative delirium, and mechanical ventilation > 48 hours. Regarding acute kidney injury, patients in the very high-volume group were at lower risk than those in the very low volume group (odds ratio [OR] = 0.53, p = 0.04). Risk factors for in-hospital mortality were previous cardiac surgery (OR = 5.75, p < 0.001), high-grade renal disease (glomerular filtration rate < 15 mL/min, OR = 5.61, p = 0.002), surgery in emergency cases (OR = 2.71, p = 0.002), and higher grade heart failure (NYHA [New York Heart Association] III/IV; OR = 1.80, p = 0.02). Risk factors for all four complication rates were atrial fibrillation and diabetes mellitus.

CONCLUSION

 Patients treated in very low volume centers (≤25 operations/year) had a similar risk regarding in-hospital mortality and most complications compared with very high-volume centers (>100 operations/year). Only in the case of acute kidney injury, very high-volume centers showed better outcomes than very low volume centers. Therefore, surgical aortic valve replacement can be performed safely independent of case volume.

Transcatheter aortic valve replacement in Germany with need for a surgical bailout

BACKGROUND

In transcatheter aortic valve replacement (TAVR), complications may force the need for a surgical bailout, but knowledge is rare about outcomes in Germany.

METHODS

Using national health records, we investigated all TAVR in German hospitals between 2007 and 2020, focusing on 2018-2020. We extracted data on those interventions with need for a surgical bailout.

RESULTS

A total of 159,643 TAVR were analyzed, with an overall rate of surgical bailout of 2.30 %, an overall in-hospital mortality of 3.85 %, and in-hospital mortality in case of bailout of 16.51 %. The number of all annual TAVR procedures increased substantially (202 to 22,972), with the rate of surgical bailout declining from 27.23 to 0.61 % and overall mortality from 11.39 to 2.29 %. However, in-hospital mortality after bailout was still high (28.37 % in 2020). The standardized rates of overall mortality and surgical bailout between 2018 and 2020 were significantly lower for balloon-expandable and self-expanding transfemoral TAVR than for transapical TAVR after risk adjustment [transapical/transfemoral balloon-expandable/transfemoral self-expanding TAVR: in-hospital mortality: 5.66 % (95 % CI 4.81 %; 6.52 %)/2.30 % (2.03 %; 2.57 %)/2.32 % (2.07 %; 2.57 %); surgical bailout: 2.33 % (1.68 %; 2.97 %)/0.79 % (0.60 %; 0.98 %)/0.42 % (0.31 %; 0.53 %)]. Coronary artery disease [risk-adjusted OR = 1.50 (1.21; 1.85), p < 0.001] and atrial fibrillation [OR = 1.29 (1.07; 1.57), p = 0.009] were found to be the main risk factors for bailout.

CONCLUSIONS

Rates of TAVR with need for a surgical bailout and overall in-hospital mortality have declined noticeably over the years in Germany. However, the outcomes are still unfavorable after surgical bailout, as in-hospital mortality is continuously high. We present risk factors for surgical bailout to improve preparation of subsequent measures. It must be a major goal to further reduce the rate of surgical bailouts in the future.

Molecular mechanisms underlying NLRP3 inflammasome activation and IL-1β production in air pollution fine particulate matter (PM2.5)-primed macrophages

Exposure to air pollution fine particulate matter (PM2.5) aggravates respiratory and cardiovascular diseases. It has been proposed that PM2.5 uptake by alveolar macrophages promotes local inflammation that ignites a systemic response, but precise underlying mechanisms remain unclear. Here, we demonstrate that PM2.5 phagocytosis leads to NLRP3 inflammasome activation and subsequent release of the pro-inflammatory master cytokine IL-1β. Inflammasome priming and assembly was time- and dose-dependent in inflammasome-reporter THP-1-ASC-GFP cells, and consistent across PM2.5 samples of variable chemical composition. While inflammasome activation was promoted by different PM2.5 surrogates, significant IL-1β release could only be observed after stimulation with transition-metal rich Residual Oil Fly Ash (ROFA) particles. This effect was confirmed in primary human monocyte-derived macrophages and murine bone marrow-derived macrophages (BMDMs), and by confocal imaging of inflammasome-reporter ASC-Citrine BMDMs. IL-1β release by ROFA was dependent on the NLRP3 inflammasome, as indicated by lack of IL-1β production in ROFA-exposed NLRP3-deficient (Nlrp3-/-) BMDMs, and by specific NLRP3 inhibition with the pharmacological compound MCC950. In addition, while ROFA promoted the upregulation of pro-inflammatory gene expression and cytokines release, MCC950 reduced TNF-α, IL-6, and CCL2 production. Furthermore, inhibition of TNF-α with a neutralizing antibody decreased IL-1β release in ROFA-exposed BMDMs. Using electron tomography, ROFA particles were observed inside intracellular vesicles and mitochondria, which showed signs of ultrastructural damage. Mechanistically, we identified lysosomal rupture, K+ efflux, and impaired mitochondrial function as important prerequisites for ROFA-mediated IL-1β release. Interestingly, specific inhibition of superoxide anion production (O2•-) from mitochondrial respiratory Complex I, but not III, blunted IL-1β release in ROFA-exposed BMDMs. Our findings unravel the mechanism by which PM2.5 promotes IL-1β release in macrophages and provide a novel link between innate immune response and exposure to air pollution PM2.5.

Center Volumes Correlate with Likelihood of Stent Implantation in German Coronary Angiography

Aims

Literature on percutaneous coronary intervention (PCI) stated an inverse relationship between hospital volume and mortality, but the effects on other characteristics are unclear.

Methods

Using German national records, all coronary angiographies with coronary artery disease in 2017 were identified. We applied risk-adjustment to account for differences in population characteristics.

Results

Of overall 528,188 patients, 55.22% received at least one stent, with on average 1.01 stents implanted in all patients. Based on those patients who received at least one stent, this corresponds to an average number of 1.82 stents. In-hospital mortality across all patients was 2.93%, length of hospital stay was 6.46 days, and mean reimbursement was €5,531. There were comparatively more emergency admissions in low volume centers and more complex cases (3-vessel disease, left main stenosis, and in-stent stenosis) in high volume centers. In multivariable regression analysis, volume and likelihood of stent implantation (p=0.003) as well as number of stents (p=0.020) were positively correlated. No relationship was seen for in-hospital mortality (p=0.105), length of stay (p=0.201), and reimbursement (p=0.108). Nonlinear influence of volume suggests a ceiling effect: In hospitals with ≤100 interventions, likelihood and number of implanted stents are lowest (∼34% and 0.6). After that, both rise steadily until a volume of 500 interventions. Finally, both remain stable in the categories of over 500 interventions (∼60% and 1.1).

Conclusion

In PCI, lower volume centers contribute to emergency care. Higher volume centers treat more complex cases and show a higher likelihood of stent implantations, with a stable safety.

Evolving trends in the surgical therapy of patients with endometrial cancer in Germany: analysis of a nationwide registry with special emphasis on perioperative outcomes

PURPOSE

Endometrial cancer (EC) is the most common gynecological malignancy in women, with increasing incidence in the last decades. Surgical therapy is the mainstay of the initial management. The present study analyzed the evolving trends of surgical therapy in Germany in patients diagnosed with EC recorded in a nationwide registry.

METHODS

All patients with the diagnosis of EC undergoing open surgery, laparoscopic surgery, and robotic-assisted laparoscopic surgery between 2007 and 2018 were identified by international classification of diseases (ICD) or specific operational codes (OPS) within the database of the German federal bureau of statistics.

RESULTS

A total of 85,204 patients underwent surgical therapy for EC. Beginning with 2013, minimal-invasive surgical therapy was the leading approach for patients with EC. Open surgery was associated with a higher risk of in-hospital mortality (1.3% vs. 0.2%, p < 0.001), of prolonged mechanical ventilation (1.3% vs. 0.2%, p < 0.001), and of prolonged hospital stay (13.7 ± 10.2 days vs. 7.2 ± 5.3 days, p < 0.001) compared to laparoscopic surgery. A total of 1551 (0.04%) patients undergoing laparoscopic surgery were converted to laparotomy. Procedure costs were highest for laparotomy, followed by robotic-assisted laparoscopy and laparoscopy (8286 ± 7533€ vs. 7083 ± 3893€ vs. 6047 ± 3509€, p < 0.001).

CONCLUSION

The present study revealed that minimal-invasive surgery has increasingly become the standard surgical procedure for patients with EC in Germany. Furthermore, minimal-invasive surgery had superior in-hospital outcomes compared to laparotomy. Moreover, the use of robotic-assisted laparoscopic surgery is increasing, with a comparable in-hospital safety profile to conventional laparoscopy.

ADP as a novel stimulus for NLRP3-inflammasome activation in mice fails to translate to humans

The NLRP3-inflammasome is a cytosolic multiprotein complex that triggers an inflammatory response to certain danger signals. Recently adenosine diphosphate (ADP) was found to activate the NLRP3-inflammasome in murine macrophages via the P2Y₁ receptor. Blockade of this signaling pathway reduced disease severity in a murine colitis-model. However, the role of the ADP/P2Y₁-axis has not yet been studied in humans. This present study confirmed ADP-dependent NLRP3-inflammasome activation in murine macrophages, but found no evidence for a role of ADP in inflammasome activation in humans. We investigated the THP1 cell line as well as primary monocytes and further looked at macrophages. Although all cells express the three human ADP-receptors P2Y₁, P2Y₁₂ and P2Y₁₃, independent of priming, neither increased ASC-speck formation could be detected with flow cytometry nor additional IL-1β release be found in the culture supernatant of ADP stimulated cells. We now show for the first time that the responsiveness of monocytes and macrophages to ADP as well as the regulation of its purinergic receptors is very much dependent on the species. Therefore the signaling pathway found to contribute to colitis in mice is likely not applicable to humans.

Impact of the COVID-19 pandemic on aortic valve replacement procedures in Germany

BACKGROUND

COVID-19 has caused the deferral of millions of elective procedures, likely resulting in a backlog of cases. We estimate the number of postponed surgical aortic valve replacement (sAVR) and transcatheter aortic valve replacement (TAVR) procedures during the first two waves of the COVID-19 pandemic in Germany.

METHODS

Using German national records, all isolated TAVR and sAVR procedures between 2007 and 2020 were identified. Using weekly TAVR and sAVR procedures between 2017 and 2019, we created a forecast for 2020 and compared it with the observed number of procedures in 2020.

RESULTS

In Germany, a total of 225,398 isolated sAVR and 159,638 isolated TAVR procedures were conducted between 2007 and 2020 that were included in our analysis. The reduction in all AVR procedures (sAVR and TAVR) for the entire year 2020 was 19.07% (95%CI: 15.19-22.95%). During the first wave of the pandemic (week 12-21), the mean weekly reduction was 32.06% (23.44-40.68%) and during the second wave of the pandemic (week 41-52), the mean weekly reduction was 25.58% (14.19-36.97%). The number of sAVR procedures decreased more than the number of TAVR procedures (24.63% vs. 16.42% for the entire year 2020).

CONCLUSION

The first year of the COVID-19 pandemic saw a substantial postponing of AVR procedures in Germany. Postponing was higher for sAVR than for TAVR procedures and less pronounced during the second wave of the COVID-19 pandemic.

A comparative gene expression matrix in Apoe-deficient mice identifies unique and atherosclerotic disease stage-specific gene regulation patterns in monocytes and macrophages

BACKGROUND AND AIMS

Atherosclerosis is a systemic and chronic inflammatory disease propagated by monocytes and macrophages. Yet, our knowledge on how transcriptome of these cells evolves in time and space is limited. We aimed at characterizing gene expression changes in site-specific macrophages and in circulating monocytes during the course of atherosclerosis.

METHODS

We utilized apolipoprotein E-deficient mice undergoing one- and six-month high cholesterol diet to model early and advanced atherosclerosis. Aortic macrophages, peritoneal macrophages, and circulating monocytes from each mouse were subjected to bulk RNA-sequencing (RNA-seq). We constructed a comparative directory that profiles lesion- and disease stage-specific transcriptomic regulation of the three cell types in atherosclerosis. Lastly, the regulation of one gene, Gpnmb, whose expression positively correlated with atheroma growth, was validated using single-cell RNA-seq (scRNA-seq) of atheroma plaque from murine and human.

RESULTS

The convergence of gene regulation between the three investigated cell types was surprisingly low. Overall 3245 differentially expressed genes were involved in the biological modulation of aortic macrophages, among which less than 1% were commonly regulated by the remote monocytes/macrophages. Aortic macrophages regulated gene expression most actively during atheroma initiation. Through complementary interrogation of murine and human scRNA-seq datasets, we showcased the practicality of our directory, using the selected gene, Gpnmb, whose expression in aortic macrophages, and a subset of foamy macrophages in particular, strongly correlated with disease advancement during atherosclerosis initiation and progression.

CONCLUSIONS

Our study provides a unique toolset to explore gene regulation of macrophage-related biological processes in and outside the atheromatous plaque at early and advanced disease stages.

Treatment of pure aortic regurgitation using surgical or transcatheter aortic valve replacement between 2018 and 2020 in Germany

Background

In pure aortic regurgitation, transcatheter aortic valve replacement (TAVR) is not yet used on a regular base. Due to constant development of TAVR, it is necessary to analyze current data.

Methods

By use of health records, we analyzed all isolated TAVR or surgical aortic valve replacements (SAVR) for pure aortic regurgitation between 2018 and 2020 in Germany.

Results

4,861 procedures-4,025 SAVR and 836 TAVR-for aortic regurgitation were identified. Patients treated with TAVR were older, showed a higher logistic EuroSCORE, and had more pre-existing diseases. While results indicate a slightly higher unadjusted in-hospital mortality for transapical TAVR (6.00%) vs. SAVR (5.71%), transfemoral TAVR showed better outcomes, with self-expanding compared to balloon-expandable transfemoral TAVR having significantly lower in-hospital mortality (2.41% vs. 5.17%; p = 0.039). After risk adjustment, balloon-expandable as well as self-expanding transfemoral TAVR were associated with a significantly lower mortality vs. SAVR (balloon-expandable: risk adjusted OR = 0.50 [95% CI 0.27; 0.94], p = 0.031; self-expanding: OR = 0.20 [0.10; 0.41], p < 0.001). Furthermore, the observed in-hospital outcomes of stroke, major bleeding, delirium, and mechanical ventilation >48 h were significantly in favor of TAVR. In addition, TAVR showed a significantly shorter length of hospital stay compared to SAVR (transapical: risk adjusted Coefficient = -4.75d [-7.05d; -2.46d], p < 0.001; balloon-expandable: Coefficient = -6.88d [-9.06d; -4.69d], p < 0.001; self-expanding: Coefficient = -7.22 [-8.95; -5.49], p < 0.001).

Conclusions

TAVR is a viable alternative to SAVR in the treatment of pure aortic regurgitation for selected patients, showing overall low in-hospital mortality and complication rates, especially with regard to self-expanding transfemoral TAVR.

COVID-19 pandemic affects STEMI numbers and in-hospital mortality: results of a nationwide analysis in Germany

Background

The COVID-19 pandemic led to extensive restrictions in Germany in 2020, including the postponement of elective interventions. We examined the impact on ST-elevation myocardial infarction (STEMI) as an acute and non-postponable disease.

Methods

Using German national records, all STEMI between 2017 and 2020 were identified. Using the number of STEMI cases between 2017 and 2019, we created a forecast for 2020 and compared it with the observed number of STEMI in 2020.

Results

From 2017 to 2020, 248,062 patients were treated for STEMI in Germany. Mean age was 65.21 years and 28.36% were female. When comparing forecasted and observed STEMI in 2020, a correlation can be seen: noticeable fewer STEMI were treated in those weeks respectively months with an increasing COVID-19 hospitalization rate (monthly percentage decrease in STEMI: March − 14.85%, April − 13.39%, November − 11.92%, December − 22.95%). At the same time, the crude in-hospital mortality after STEMI increased significantly at the peaks of the first and second waves (relative risk/RR of monthly in-hospital mortality: April RR = 1.11 [95% CI 1.02; 1.21], November RR = 1.13 [1.04; 1.24], December RR = 1.16 [1.06; 1.27]).

Conclusion

The COVID-19 pandemic led to a noticeable decrease in the number of STEMI interventions in Germany at the peaks of the first and second waves in 2020, corresponding to an increase in COVID-19 hospitalizations. At the same time, in-hospital mortality after STEMI increased significantly in these phases.

Graphical abstract

Impact of the COVID-19 pandemic on STEMI numbers and in-hospital mortality in Germany. Relative difference between forecasted and observed STEMI numbers (above figure), the relative risk of in-hospital mortality (middle figure) as well as number of new hospital admissions for COVID-19 per million inhabitants according to Roser et al.²⁷ (bottom figure).

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-022-02102-2.

Analysis of surgical bailout after transcatheter aortic valve replacement in Germany

Background

Severe complications during transcatheter aortic valve replacement (TAVR) may require a surgical bailout. However, little is known about the outcomes after bailout in Germany.

Methods

All TAVR between 2007 and 2020 were identified using German national electronic health records, with focus on 2018 to 2020. Additionally, those procedures requiring surgical bailout were selected.

Results

A total of 159,643 patients received TAVR. Overall rate of surgical bailout was 2.30% and overall in-hospital mortality 3.85%. In-hospital mortality after surgical bailout was 16.51%. While the annual number of procedures in all TAVR rose steeply (202 to 22,972), the rate of surgical bailout dropped from 27.23 to 0.61% and that of overall mortality from 11.39 to 2.29%. However, mortality in case of surgical bailout remained high with 28.37% in 2020. After risk adjustment, in 2018 to 2020, standardized rates of overall in-hospital mortality and surgical bailout for both balloon-expandable and self-expanding transfemoral TAVR were significantly lower than for transapical TAVR (transapical vs transfemoral balloon-expandable vs self-expanding TAVR: in-hospital mortality: 5.66% [95% CI 4.81%; 6.52%] vs 2.30% [2.03%; 2.57%] vs 2.32% [2.07%; 2.57%]; surgical bailout: 2.33% [1.68%; 2.97%] vs 0.79% [0.60%; 0.98%] vs 0.42% [0.31%; 0.53%]). Main risk factors for surgical bailout were coronary artery disease (risk adjusted OR=1.50 [1.21; 1.85], p&lt;0.001), atrial fibrillation (OR=1.29 [1.07; 1.57], p=0.009), and higher grade heart failure NYHA III/IV (OR=1.26 [1.01; 1.57], p=0.037).

Conclusion

Rates of surgical bailout as well as overall in-hospital mortality after TAVR decrease substantially over the years. However, in the case of surgical bailout, outcomes remain poor with a constantly high in-hospital mortality.

Funding Acknowledgement

Type of funding sources: None.

Volume-outcome relationship in emergency transcatheter aortic valve implantations in Germany

Background

An inverse volume-outcome relationship in transcatheter aortic valve implantation (TAVI) has been demonstrated in the literature but little is known about emergency cases.

Methods

All isolated balloon-expandable and self-expanding transfemoral TAVI in 2018 were identified using German national electronic health records. Additionally, those patients with an emergency admission were selected.

Results

A total of 17,295 patients received TAVI, 1,682 of these cases had an emergency admission. Of the emergency cases, 49.2% were female, mean age was 81.2 years and logistic EuroSCORE was 23.3%. Relatively more emergency cases were treated in lower volume centers than in higher volume centers (p&lt;0.001): Centers performing &lt;50 TAVI had an emergency admission rate of ∼15% while centers performing &gt;200 TAVI were associated with a rate of ∼11%. Analyzing the outcomes for a volume increase per 10 emergency cases using propensity score adjustment, higher volume centers showed significantly better results than lower volume centers for in-hospital mortality (OR=0.872, p=0.043), major bleeding (OR=0.772, p=0.001), stroke (OR=0.816, p=0.044), mechanical ventilation &gt;48h (OR=0.749, p=0.001), length of hospital stay (risk adjusted difference in days of hospitalization per 10 emergency admissions: −1.01 days, p&lt;0.001), and reimbursement (risk adjusted difference in reimbursement per 10 emergency admissions: −€314.89, p&lt;0.001). No correlation was seen in acute kidney injury (OR=0.951, p=0.104), postoperative delirium (OR=0.975, p=0.480), and permanent pacemaker implantation (OR=1.010, p=0.732).

Conclusion

In transfemoral TAVI, lower volume centers treat relatively more emergency cases in Germany, but higher volume centers provide significantly better outcomes regarding in-hospital mortality and complication rates as well as resource utilization parameters.

Funding Acknowledgement

Type of funding sources: None.

COVID-19 pandemic affects STEMI numbers and in-hospital mortality: results of a nationwide analysis in Germany

Background

The COVID-19 pandemic led to extensive restrictions in Germany in 2020, including the postponement of elective interventions. We examined the impact on ST-elevation myocardial infarction (STEMI) as an acute and non-postponable disease.

Methods

Using German national records, all STEMI between 2017 and 2020 were identified. Using the number of STEMI cases between 2017 and 2019, we created a forecast for 2020 using poisson regression models and compared it with the observed number of STEMI in 2020.

Results

From 2017 to 2020, 248,062 patients were treated for a STEMI in Germany. Mean age was 65.21 years and 28.36% were female. When comparing forecasted and observed STEMI in 2020, a correlation can be seen: Noticeably fewer STEMI were treated in those weeks respectively months with an increasing COVID-19 hospitalization rate (monthly percentage decrease in STEMI: March −14.85% April −13.39%, November −11.92%, December −22.95%). At the same time, the risk-adjusted in-hospital mortality increased significantly at the peaks of the first and second waves (monthly in-hospital mortality: April RR=1.11 [95% CI 1.02; 1.21], November 1.13 [1.04; 1.24], December 1.16 [1.06; 1.27]).

Conclusion

The COVID-19 pandemic led to a noticeable decrease in the number of STEMI interventions in Germany at the peaks of the first and second waves in 2020, corresponding to an increase in COVID-19 hospitalizations. At the same time, in-hospital mortality after STEMI increased significantly in these phases.

Funding Acknowledgement

Type of funding sources: None.

Annual hospital procedural volume and outcome in extracorporeal membrane oxygenation for respiratory failure

BACKGROUND

The hospital mortality of patients suffering from pulmonary failure requiring venovenous extracorporeal membrane oxygenation (V-V ECMO) or extracorporeal carbon dioxide removal (ECCO₂ R) is high. It is unclear whether outcome correlates with a hospital's annual procedural volume.

METHODS

Data on all V-V ECMO and ECCO₂ R cases treated from 2007 to 2019 was retrieved from the German Institute for Medical Documentation and Information. Comorbidities and outcomes were assessed by DRG, OPS, and ICD codes. The study population was divided into 5 groups depending on annual hospital V-V ECMO and ECCO₂ R volumes (<10 cases; 10-19 cases; 20-29 cases; 30-49 cases; ≥50 cases). Primary outcome was hospital mortality.

RESULTS

A total of 25,096 V-V ECMO and 3,607 ECCO₂ R cases were analyzed. V-V ECMO hospitals increased from 89 in 2007 to 214 in 2019. Hospitals handling <10 cases annually increased especially (64 in 2007 to 149 in 2019). V-V ECMO cases rose from 807 in 2007 to 2,597 in 2019. Over 50% were treated in hospitals handling ≥30 cases annually. Hospital mortality was independent of the annual hospital procedural volume (55.3%; 61.3%; 59.8%; 60.2%; 56.3%, respectively, p=0.287). We detected no differences when comparing hospitals handling <30 cases to those with ≥30 annually (p=0.659). The numbers of ECCO₂ R hospitals and cases has dropped since 2011 (287 in 2007 to 48 in 2019). No correlation between annual hospital procedural volume and hospital mortality was identified (p=0.914).

CONCLUSION

The number of hospitals treating patients requiring V-V ECMO and V-V ECMO cases rose from 2007 to 2019, while ECCO₂ R hospitals and their case numbers decreased. We detected no correlation between annual hospital V-V ECMO or ECCO₂ R volume and hospital mortality.

Circulating Autoantibodies Recognizing Immunodominant Epitopes From Human Apolipoprotein B Associate With Cardiometabolic Risk Factors, but Not With Atherosclerotic Disease

Rationale

Atherosclerosis is a chronic inflammatory disease of large arteries that involves an autoimmune response with autoreactive T cells and auto-antibodies recognizing Apolipoprotein B (ApoB), the core protein of low-density lipoprotein (LDL). Here, we aimed to establish a clinical association between circulating human ApoB auto-antibodies with atherosclerosis and its clinical risk factors using a novel assay to detect auto-antibodies against a pool of highly immunogenic ApoB-peptides.

Methods and Results

To detect polyclonal IgM- and IgG-antibodies recognizing ApoB, we developed a chemiluminescent sandwich ELISA with 30 ApoB peptides selected by an in silico assay for a high binding affinity to MHC-II, which cover more than 80% of known MHC-II variants in a Caucasian population. This pre-selection of immunogenic self-peptides accounted for the high variability of human MHC-II, which is fundamental to allow T cell dependent generation of IgG antibodies. We quantified levels of ApoB-autoantibodies in a clinical cohort of 307 patients that underwent coronary angiography. Plasma anti-ApoB IgG and IgM concentrations showed no differences across healthy individuals (n = 67), patients with coronary artery disease (n = 179), and patients with an acute coronary syndrome (n = 61). However, plasma levels of anti-ApoB IgG, which are considered pro-inflammatory, were significantly increased in patients with obesity (p = 0.044) and arterial hypertension (p < 0.0001). In addition, patients diagnosed with the metabolic syndrome showed significantly elevated Anti-ApoB IgG (p = 0.002). Even when normalized for total plasma IgG, anti-ApoB IgG remained highly upregulated in hypertensive patients (p < 0.0001). We observed no association with triglycerides, total cholesterol, VLDL, or LDL plasma levels. However, total and normalized anti-ApoB IgG levels negatively correlated with HDL. In contrast, total and normalized anti-ApoB IgM, that have been suggested as anti-inflammatory, were significantly lower in diabetic patients (p = 0.012) and in patients with the metabolic syndrome (p = 0.005).

Conclusion

Using a novel ELISA method to detect auto-antibodies against ApoB in humans, we show that anti-ApoB IgG associate with cardiovascular risk factors but not with the clinical appearance of atherosclerosis, suggesting that humoral immune responses against ApoB are shaped by cardiovascular risk factors but not disease status itself. This novel tool will be helpful to develop immune-based risk stratification for clinical atherosclerosis in the future.

Platelet Subtypes in Inflammatory Settings

In addition to their essential role in hemostasis and thrombosis, platelets also modulate inflammatory reactions and immune responses. This is achieved by specialized surface receptors as well as secretory products including inflammatory mediators and cytokines. Platelets can support and facilitate the recruitment of leukocytes into inflamed tissue. The various properties of platelet function make it less surprising that circulating platelets are different within one individual. Platelets have different physical properties leading to distinct subtypes of platelets based either on their function (procoagulant, aggregatory, secretory) or their age (reticulated/immature, non-reticulated/mature). To understand the significance of platelet phenotypic variation, qualitatively distinguishable platelet phenotypes should be studied in a variety of physiological and pathological circumstances. The advancement in proteomics instrumentation and tools (such as mass spectrometry-driven approaches) improved the ability to perform studies beyond that of foundational work. Despite the wealth of knowledge around molecular processes in platelets, knowledge gaps in understanding platelet phenotypes in health and disease exist. In this review, we report an overview of the role of platelet subpopulations in inflammation and a selection of tools for investigating the role of platelet subpopulations in inflammation.

The Role of Tumor Necrosis Factor Associated Factors (TRAFs) in Vascular Inflammation and Atherosclerosis

TNF receptor associated factors (TRAFs) represent a family of cytoplasmic signaling adaptor proteins that regulate, bundle, and transduce inflammatory signals downstream of TNF- (TNF-Rs), interleukin (IL)-1-, Toll-like- (TLRs), and IL-17 receptors. TRAFs play a pivotal role in regulating cell survival and immune cell function and are fundamental regulators of acute and chronic inflammation. Lately, the inhibition of inflammation by anti-cytokine therapy has emerged as novel treatment strategy in patients with atherosclerosis. Likewise, growing evidence from preclinical experiments proposes TRAFs as potent modulators of inflammation in atherosclerosis and vascular inflammation. Yet, TRAFs show a highly complex interplay between different TRAF-family members with partially opposing and overlapping functions that are determined by the level of cellular expression, concomitant signaling events, and the context of the disease. Therefore, inhibition of specific TRAFs may be beneficial in one condition and harmful in others. Here, we carefully discuss the cellular expression and signaling events of TRAFs and evaluate their role in vascular inflammation and atherosclerosis. We also highlight metabolic effects of TRAFs and discuss the development of TRAF-based therapeutics in the future.

Effects of Short Term Adiponectin Receptor Agonism on Cardiac Function and Energetics in Diabetic db/db Mice

Objective

Impaired cardiac efficiency is a hallmark of diabetic cardiomyopathy in models of type 2 diabetes. Adiponectin receptor 1 (AdipoR1) deficiency impairs cardiac efficiency in non-diabetic mice, suggesting that hypoadiponectinemia in type 2 diabetes may contribute to impaired cardiac efficiency due to compromised AdipoR1 signaling. Thus, we investigated whether targeting cardiac adiponectin receptors may improve cardiac function and energetics, and attenuate diabetic cardiomyopathy in type 2 diabetic mice.

Methods

A non-selective adiponectin receptor agonist, AdipoRon, and vehicle were injected intraperitoneally into Eight-week-old db/db or C57BLKS/J mice for 10 days. Cardiac morphology and function were evaluated by echocardiography and working heart perfusions.

Results

Based on echocardiography, AdipoRon treatment did not alter ejection fraction, left ventricular diameters or left ventricular wall thickness in db/db mice compared to vehicle-treated mice. In isolated working hearts, an impairment in cardiac output and efficiency in db/db mice was not improved by AdipoRon. Mitochondrial respiratory capacity, respiration in the presence of oligomycin, and 4-hydroxynonenal levels were similar among all groups. However, AdipoRon induced a marked shift in the substrate oxidation pattern in db/db mice towards increased reliance on glucose utilization. In parallel, the diabetes-associated increase in serum triglyceride levels in vehicle-treated db/db mice was blunted by AdipoRon treatment, while an increase in myocardial triglycerides in vehicle-treated db/db mice was not altered by AdipoRon treatment.

Conclusion

AdipoRon treatment shifts myocardial substrate preference towards increased glucose utilization, likely by decreasing fatty acid delivery to the heart, but was not sufficient to improve cardiac output and efficiency in db/db mice.

In-hospital outcomes of patients undergoing concomitant aortic and mitral valve replacement in Germany

 

OBJECTIVES

To evaluate in-hospital outcomes of concomitant mitral valve replacement (MVR) in patients undergoing conventional aortic valve replacement due to aortic stenosis in a nationwide cohort.

METHODS

Administrative data from all patients with aortic stenosis undergoing conventional aortic and concomitant MVR (reason for MVR not specified) between 2017 and 2018 in Germany were analysed.

RESULTS

A total of 2597 patients with a preoperative logistic EuroScore of 9.81 (standard deviation: 8.56) were identified. In-hospital mortality was 6.8%. An in-hospital stroke occurred in 3.4%, acute kidney injury in 16.3%, prolonged mechanical ventilation of more than 48 h in 16.3%, postoperative delirium in 15.8% and postoperative pacemaker implantation in 7.6% of the patients. Mean hospital stay was 16.5 (standard deviation: 12.1) days. Age [odds ratio (OR): 1.03; P = 0.019], New York Heart Association class III or IV (OR: 1.63; P = 0.012), previous cardiac surgery (OR: 2.85, P = 0.002), peripheral vascular disease (OR: 2.01, P = 0.031), pulmonary hypertension (OR: 1.63, P = 0.042) and impaired renal function (glomerular filtration rate <15, OR: 3.58, P = 0.001; glomerular filtration rate <30, OR: 2.51, P = 0.037) were identified as independent predictors for in-hospital mortality.

CONCLUSIONS

In this nationwide analysis, concomitant aortic and MVR was associated with acceptable in-hospital mortality, morbidity and length of in-hospital stay. The regression analyses may help to identify high-risk patients and further optimize treatment strategies.

P2Y12 Inhibition in Murine Myocarditis Results in Reduced Platelet Infiltration and Preserved Ejection Fraction

Previous mouse studies have shown the increased presence of platelets in the myocardium during early stages of myocarditis and their selective detection by MRI. Here, we aimed to depict early myocarditis using molecular contrast-enhanced ultrasound of activated platelets, and to evaluate the impact of a P2Y12 receptor platelet inhibition. Experimental autoimmune myocarditis was induced in BALB/c mice by subcutaneous injection of porcine cardiac myosin and complete Freund adjuvant (CFA). Activated platelets were targeted with microbubbles (MB) coupled to a single-chain antibody that binds to the "ligand-induced binding sites" of the GPIIb/IIIa-receptor (=LIBS-MB). Alongside myocarditis induction, a group of mice received a daily dose of 100 g prasugrel for 1 month. Mice injected with myosin and CFA had a significantly deteriorated ejection fraction and histological inflammation on day 28 compared to mice only injected with myosin. Platelets infiltrated the myocardium before reduction in ejection fraction could be detected by echocardiography. No selective binding of the LIBS-MB contrast agent could be detected by either ultrasound or histology. Prasugrel therapy preserved ejection fraction and significantly reduced platelet aggregates in the myocardium compared to mice without prasugrel therapy. Therefore, P2Y12 inhibition could be a promising early therapeutic target in myocarditis, requiring further investigation.

Advantages of score-based delirium detection compared to a clinical delirium assessment-a retrospective, monocentric cohort study

Purpose

Delirium is an underdiagnosed complication on intensive care units (ICU). We hypothesized that a score-based delirium detection using the Nudesc score identifies more patients compared to a traditional diagnosis of delirium by ICU physicians.

Methods

In this retrospective study, all patients treated on a general medical ICU with 30 beds in a university hospital in 2019 were analyzed. Primary outcome was a documented physician diagnosis of delirium, or a delirium score ≥2 using the Nudesc.

Results

In 205/943 included patients (21.7%), delirium was diagnosed by ICU physicians compared to 438/943 (46.4%; ratio 2.1) by Nudesc≥2. Both assessments were independent predictors of ICU stay (p<0.01). The physician diagnosis however was no independent predictor of mortality (OR 0.98 (0.57–1.72); p = 0.989), in contrast to the score-based diagnosis (OR 2.31 (1.30–4.10); p = 0.004). Subgroup analysis showed that physicians underdiagnosed delirium in case of hypoactive delirium and delirium in patients with female gender and in patients with an age below 60 years.

Conclusion

Delirium in patients with hypoactive delirium, female patients and those below 60 years was underdiagnosed by physicians. The score-based delirium diagnosis detected delirium more frequently and correlated with ICU mortality and stay.

Incidence and predictors of delirium on the intensive care unit after acute myocardial infarction, insight from a retrospective registry

OBJECTIVES

This study aimed to identify the incidence and potential risk factors for delirium after myocardial infarction (MI).

BACKGROUND

Delirium is a common complication on intensive care units. Data on incidence and especially on predictors of delirium in patients after acute MI are rare.

METHODS

In this retrospective study, all patients hospitalized for MI treated with coronary angiography in an university hospital in 2018 were included and analyzed. Onset of delirium within the first 5 days after MI was attributed to the MI and was defined by a Nursing Delirium screening scale (NuDesc) ≥2. This score is taken as part of daily care in every patient on intensive care unit three times a day by especially trained nurses.

RESULTS

A total of 624 patients with MI (age 68.5 ± 13.2 years, ST-elevation MI 41.6%, hospital mortality 3.2%) were included in the study. Delirium was detected in 10.9% of all patients. In the subgroup of patients with a stay on the intensive care unit (ICU) for more than 24 hr (n = 229), delirium was detected in 29.7%. Hospital and ICU stay were significantly longer in patients with delirium (p < .001). Delirium was an independent predictor of prolonged ICU-stay. Independent predictors of delirium were age, dementia, alcohol abuse, cardiac arrest, hypotension, and leucocytosis. Infarct size or presentation with ST-elevation were not associated with incidence of delirium.

CONCLUSION

Development of delirium is frequent after acute MI and prolongs hospitalization. Incidence of delirium is associated with clinical instability, preexisting comorbidity, and age rather than MI type or size.

Ventral calcification in the common femoral artery: A risk factor for major transcatheter aortic valve intervention access site complications

OBJECTIVES

We aimed to identify risk factors for major transcatheter aortic valve intervention (TAVI) access site complications based on detailed analysis of the preprocedural computed tomography angiogram (CTA).

BACKGROUND

Transfemoral TAVI has become the treatment of choice for severe aortic stenosis in elderly patients, especially with increased perioperative risk. Frailty, however, favors complications at the vascular access site due to the large bore vascular sheath devices necessary for valve deployment.

METHODS

In this monocentric study, we retrospectively analyzed the preprocedural CTA of 417 consecutive patients that received transfemoral TAVI between 2015 and 2019 to quantify vessel diameter, calcification volume and calcified plaque location in detail within 10 cm proximal to the femoral bifurcation.

RESULTS

The mean age of the study cohort was 81.4 ± 6.5 years with a STS of 8 ± 5.2 representing a population at increased periprocedural risk. 54.4% of patients were female. Major vascular access site complications occurred in 8.2% of patients. Major vascular complications correlated statistically with a sheath-to-vessel diameter (SFAR) when measured 1 cm proximal to the femoral bifurcation using a line-derived diameter and ventral calcification within the first 5 cm proximal to the bifurcation. In contrast, overall calcification volume had no influence.

CONCLUSIONS

Transfemoral TAVI harbors a considerable risk for vascular access site complications especially if vessel diameter is too small to comfortably host the sheath diameter at the area of the femoral bifurcation. For preprocedural TAVI planning and risk assessment, location of calcification, especially if located ventrally, seems to be more relevant than consideration of overall calcification alone.

Myeloid cell-specific Irf5 deficiency stabilizes atherosclerotic plaques in Apoe-/- mice

OBJECTIVE

Interferon regulatory factor (IRF) 5 is a transcription factor known for promoting M1 type macrophage polarization in vitro. Given the central role of inflammatory macrophages in promoting atherosclerotic plaque progression, we hypothesize that myeloid cell-specific deletion of IRF5 is protective against atherosclerosis.

METHODS

Female Apoe-/-LysmCre/+Irf5fl/fl and Apoe-/-Irf5fl/fl mice were fed a high-cholesterol diet for three months. Atherosclerotic plaque size and compositions as well as inflammatory gene expression were analyzed. Mechanistically, IRF5-dependent bone marrow-derived macrophage cytokine profiles were tested under M1 and M2 polarizing conditions. Mixed bone marrow chimeras were generated to determine intrinsic IRF5-dependent effects on macrophage accumulation in atherosclerotic plaques.

RESULTS

Myeloid cell-specific Irf5 deficiency blunted LPS/IFNγ-induced inflammatory gene expression in vitro and in the atherosclerotic aorta in vivo. While atherosclerotic lesion size was not reduced in myeloid cell-specific Irf5-deficient Apoe-/- mice, plaque composition was favorably altered, resembling a stable plaque phenotype with reduced macrophage and lipid contents, reduced inflammatory gene expression and increased collagen deposition alongside elevated Mertk and Tgfβ expression. Irf5-deficient macrophages, when directly competing with wild type macrophages in the same mouse, were less prone to accumulate in atherosclerotic lesion, independent of monocyte recruitment. Irf5-deficient monocytes, when exposed to oxidized low density lipoprotein, were less likely to differentiate into macrophage foam cells, and Irf5-deficient macrophages proliferated less in the plaque.

CONCLUSION

Our study provides genetic evidence that selectively altering macrophage polarization induces a stable plaque phenotype in mice.

Deficiency of Endothelial CD40 Induces a Stable Plaque Phenotype and Limits Inflammatory Cell Recruitment to Atherosclerotic Lesions in Mice

OBJECTIVES

The co-stimulatory CD40L-CD40 dyad exerts a critical role in atherosclerosis by modulating leukocyte accumulation into developing atherosclerotic plaques. The requirement for cell-type specific expression of both molecules, however, remains elusive. Here, we evaluate the contribution of CD40 expressed on endothelial cells (ECs) in a mouse model of atherosclerosis.

METHODS AND RESULTS

Atherosclerotic plaques of apolipoprotein E-deficient (Apoe -/- ) mice and humans displayed increased expression of CD40 on ECs compared with controls. To interrogate the role of CD40 on ECs in atherosclerosis, we induced EC-specific (BmxCreERT2-driven) deficiency of CD40 in Apoe -/- mice. After feeding a chow diet for 25 weeks, EC-specific deletion of CD40 (iEC-CD40) ameliorated plaque lipid deposition and lesional macrophage accumulation but increased intimal smooth muscle cell and collagen content, while atherosclerotic lesion size did not change. Leukocyte adhesion to the vessel wall was impaired in iEC-CD40-deficient mice as demonstrated by intravital microscopy. In accord, expression of vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) in the vascular endothelium declined after deletion of CD40. In vitro, antibody-mediated inhibition of human endothelial CD40 significantly abated monocyte adhesion on ECs.

CONCLUSION

Endothelial deficiency of CD40 in mice promotes structural features associated with a stable plaque phenotype in humans and decreases leukocyte adhesion. These results suggest that endothelial-expressed CD40 contributes to inflammatory cell migration and consecutive plaque formation in atherogenesis.

Self-expanding and balloon-expandable transfemoral transcatheter aortic valve replacement: in-hospital outcomes in Germany

Background

The impact of valve type used in transfemoral transcatheter aortic valve replacement (TF-TAVR) on outcomes is currently under discussion.

Purpose

We examine the in-hospital outcomes of balloon-expandable (BE) and self-expanding (SE) valves in a complete national cohort in Germany in 2018.

Methods

All 17,295 patients receiving TF-TAVR with BE (N=9,882) or SE (N=7,413) valves in Germany in 2018 were identified. Outcomes were analyzed for the endpoints in-hospital mortality, major bleeding, stroke, acute kidney injury, postoperative delirium, mechanical ventilation &gt;48h, length of hospital stay, and reimbursement. Since there was no randomization of patients to the two treatment options, logistic or linear regression models were carried out using 22 baseline patient characteristics and center-specific variables as potential confounders. Propensity score methods served as sensitivity analysis.

Results

Both valve types differed significantly in baseline characteristics with higher EuroSCORE (p&lt;0.001), age (p&lt;0.001) and rate of female sex (p&lt;0.001) in patients treated with SE valves. After risk adjustment, there were no marked differences in outcomes for in-hospital mortality (risk adjusted odds ratio (aOR) for SE instead of BE: 0.94 [95% CI 0.76; 1.17], p=0.617), major bleeding (aOR 0.91 [0.73; 1.14], p=0.400), stroke (aOR 1.13 [0.88; 1.46], p=0.347), acute kidney injury (aOR 0.97 [0.85; 1.10], p=0.621), postoperative delirium (aOR 1.09 [0.96; 1.24], p=0.184), mechanical ventilation &gt;48h (aOR 0.98 [0.77; 1.25], p=0.893), length of hospital stay (risk adjusted difference in days of hospitalization: −0.05 [−0.34; 0.25], p=0.762) and reimbursement (−€72 [−€291; €147], p=0.519). Similar results were found using propensity score methods.

Conclusion

Outcomes in contemporary TF-TAVR procedures are broadly equivalent regardless of the valve type used. Major complications rarely occur in both types of valve.

Funding Acknowledgement

Type of funding sources: None. Self- vs balloon-expanding TF-TAVR

Quantitative and qualitative composition of the innate immune response are equally important in wound healing after myocardial infarction

Background

Emergency hematopoiesis (EH) serves as the foundation of monocyte-derived and macrophage (Mφ) driven efferocytosis and ventricular remodeling after myocardial infarction (MI). Excessive myelopoiesis, however, can stipulate maladaptive wound healing and its therapeutic reduction may be a novel approach to preserve cardiac function. All-trans retinoic acid (ATRA) is a pleiotropic modulator of EH and innate immunity shielding hematopoietic stem cells from activation and driving survival and differentiation of myeloid cells.

Purpose

This study aimed to investigate this intriguing interplay of ATRA in wound healing after MI.

Methods

MI was induced by permanent coronary ligation in C57BL/6 mice and treated with daily injections of either ATRA (30mg/kg) or DMSO (vehicle) up to five days, starting 24h after ligation. Flow cytometry (FACS) was used for cell cycle analysis and immunophenotyping of leukocytes in bone marrow (BM), blood and heart. Immunohistochemistry (IH), masson trichrome (MT) staining and echocardiography evaluated inflammatory-fibrotic and functional development. Cytokine expression was analyzed by qPCR in bulk infarct and isolated, polarized Mφ-populations of BM-derived and cardiac resident origin.

Results

On day 2 after MI, EH was significantly reduced in ATRA-treated mice as compared to vehicle controls by means of cell cycle activity (n=6–13 per group; p&lt;0,01) and myeloid cells in BM, blood and infarct tissue (n=5–13; p&lt;0,05). Consequently, mRNA-expression of key inflammatory cytokines, IL-1β and TNFα, was diminished in the infarct tissue in this early phase (n=5–12; p&lt;0,05). These changes, however, failed to preserve cardiac function and ventricular remodeling, 21 days after MI (n=10–11; not significant). By qPCR, non-canonical activation of recruited ATRA-primed monocyte-derived Mφ, was found to propagate a pro-inflammatory phenotype with higher expression of MMP2 and MMP9 in sorted cardiac Mφ (n=4–5; p&lt;0,001). Furthermore, prominent IL-1β-expression in M2-polarized BM-derived Mφ indicated an impaired anti-inflammatory phenotype after ATRA treatment (n=4–6; p&lt;0,05). Strikingly, these changes also occurred in remote myocardium where IH revealed a 2-fold increase of CD11b - positive myeloid cells accompanied by increased expression of TNFα and TGFβ (n=9; p&lt;0,001). MT-staining, performed 21 days after MI, demonstrated an almost 3-fold increase in collagen deposition in remote myocardium of ATRA treated mice in contrast to vehicle controls (n=4–6; p&lt;0,0001).

Conclusion

Despite a beneficial reduction of EH after MI, short-term treatment with ATRA induced profound and persisting changes in the cytokine expression of monocyte-derived Mφ, which significantly altered their function and thus prevented improvements in cardiac function. Our data provide evidence that quantitative and qualitative changes in innate immunity are equally important for cardiac remodeling after MI.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft

Genetic Deficiency of TRAF5 Promotes Adipose Tissue Inflammation and Aggravates Diet-Induced Obesity in Mice

Objective: The accumulation of inflammatory leukocytes is a prerequisite of adipose tissue inflammation during cardiometabolic disease. We previously reported that a genetic deficiency of the intracellular signaling adaptor TRAF5 (TNF [tumor necrosis factor] receptor-associated factor 5) accelerates atherosclerosis in mice by increasing inflammatory cell recruitment. Here, we tested the hypothesis that an impairment of TRAF5 signaling modulates adipose tissue inflammation and its metabolic complications in a model of diet-induced obesity in mice. Approach and Results: To induce diet-induced obesity and adipose tissue inflammation, wild-type or Traf5-/- mice consumed a high-fat diet for 18 weeks. Traf5-/- mice showed an increased weight gain, impaired insulin tolerance, and increased fasting blood glucose. Weight of livers and peripheral fat pads was increased in Traf5-/- mice, whereas lean tissue weight and growth were not affected. Flow cytometry of the stromal vascular fraction of visceral adipose tissue from Traf5-/- mice revealed an increase in cytotoxic T cells, CD11c+ macrophages, and increased gene expression of proinflammatory cytokines and chemokines. At the level of cell types, expression of TNF[alpha], MIP (macrophage inflammatory protein)-1[alpha], MCP (monocyte chemoattractant protein)-1, and RANTES (regulated on activation, normal T-cell expressed and secreted) was significantly upregulated in Traf5-deficient adipocytes but not in Traf5-deficient leukocytes from visceral adipose tissue. Finally, Traf5 expression was lower in adipocytes from obese patients and mice and recovered in adipose tissue of obese patients one year after bariatric surgery. Conclusions: We show that a genetic deficiency of TRAF5 in mice aggravates diet-induced obesity and its metabolic derangements by a proinflammatory response in adipocytes. Our data indicate that TRAF5 may promote anti-inflammatory and obesity-preventing signaling events in adipose tissue.

Delirium in Critically Ill Patients with and without COVID-19-A Retrospective Analysis

BACKGROUND

Delirium complicating the course of Intensive care unit (ICU) therapy is a known driver of morbidity and mortality. It has been speculated that infection with the neurotrophic SARS-CoV-2 might promote delirium.

METHODS

Retrospective registry analysis including all patients treated at least 48 h on a medical intensive care unit. The primary endpoint was development of delirium as diagnosed by Nursing Delirium screening scale ≥2. Results were confirmed by propensity score matching.

RESULTS

542 patients were included. The primary endpoint was reached in 352/542 (64.9%) patients, without significant differences between COVID-19 patients and non-COVID-19 patients (51.4% and 65.9%, respectively, p = 0.07) and correlated with prolonged ICU stay in both groups. In a subgroup of patients with ICU stay >10 days delirium was significantly lower in COVID-19 patients (p ≤ 0.01). After adjustment for confounders, COVID-19 correlated independently with less ICU delirium (p ≤ 0.01). In the propensity score matched cohort, patients with COVID-19 had significantly lower delirium incidence compared to the matched control patients (p ≤ 0.01).

CONCLUSION

Delirium is frequent in critically ill patients with and without COVID-19 treated at an intensive care unit. Data suggests that COVID-19 itself is not a driver of delirium per se.

Outcomes of female and male patients suffering from coronary artery disease: A nation-wide registry of patients admitted as emergency

Presentation and mortality of coronary artery disease (CAD) substantially differs in both sexes. Most of the existing data analyzing sex differences is older than 10 years and mostly was retrieved in clinical trials, which are potentially structured with a bias against the inclusion of women, leading to a potential selection-bias. Meanwhile, with better diagnostic and therapeutic options, actual data analyzing sex differences in emergency CAD patients is rare.Data on all emergency case numbers with CAD diagnosis in Germany 2017 was retrieved from the German Institute for Medical Documentation and Information. DRG, OPS, and ICD codes were used to determine comorbidities, in-hospital course, and outcome. Competing risk regression analysis for in-hospital mortality was performed analyzing age, European System for Cardiac Operative Risk Evaluation (EuroSCORE), severity of CAD, clinical presentation type and sex.264,742 patients were included. Female patients were older and had more comorbidities. Three-vessel CAD was significantly less present in female patients (36.5% vs 47.5%; P < .001). After adjusting for age, EuroSCORE and severity of CAD, female sex was an independent predictor of lower in-hospital mortality (subdistribution hazard ratio [sHR] 0.94, 95% CI: 0.90-0.98, P = .002) in the whole cohort and in non-ST-segment elevation myocardial infarction (NSTEMI) patients (sHR 0.85, 95% CI: 0.79-0.92, P < .001), whereas in ST-segment elevation myocardial infarction (STEMI) patients, female sex was associated with a higher in-hospital mortality (sHR 1.07, 95% CI: 1.01-1.14, P = .029).In all patients admitted as emergency with CAD diagnosis and in all NSTEMI patients, female sex is protective, whereas in STEMI patients, females show a higher in-hospital mortality risk.

The impact of transcatheter aortic valve implantation planning and procedure on acute and chronic renal failure

BACKGROUND

Severe aortic valve stenosis inhibits renal perfusion, thereby potentially worsening renal function, in particular in elderly patients most often assigned to transcatheter aortic valve implantation (TAVI). Pre-TAVI diagnostics and the procedure itself may adversely impact renal function, however renal perfusion and function may also improve post-procedure. This study aimed to clarify the impact of TAVI planning and procedure on kidney function METHODS: In this retrospective study, kidney function of patients who underwent transfemoral TAVI at a tertiary university hospital between 2016 and 2019 was analyzed. The present study investigated kidney function at baseline, after computed tomography (CT) was performed for evaluation of TAVI, after TAVI, at discharge and at follow-up.

RESULTS

Among 366 patients, the prevalence of acute kidney injury (AKI) was 14.5% after TAVI. Independent predictors of AKI were arterial hypertension, baseline creatinine, AKI post CT and coronary intervention during pre-procedural diagnostics. At discharge and follow-up, 2.1% and 3.4%, respectively had sustained relevant impairment of kidney function (defined as creatinine/baseline creatinine > 1.5 or renal replacement therapy). Patients with known chronic kidney disease showed no higher rates of short- and long-term impairment, but higher rates of improvement of renal function after TAVI.

CONCLUSIONS

In most cases TAVI does not worsen renal function. A sustained impairment after TAVI was found in only a few cases. This was independent of reduced baseline kidney function. Transfemoral TAVI can thus be planned and performed even in patients with higher stages of chronic kidney disease.

The Use and Outcomes of Cerebral Protection Devices for Patients Undergoing Transfemoral Transcatheter Aortic Valve Replacement in Clinical Practice

OBJECTIVES

This study hypothesized that cerebral protection prevents strokes in patients undergoing transfemoral transcatheter aortic valve replacement (TAVR) in clinical practice.

BACKGROUND

Preventing strokes is an important aim in TAVR procedures. Embolic protection devices may protect against cardiac embolism during TAVR, but their use and outcomes in clinical practice remain controversial.

METHODS

Isolated transfemoral TAVR procedures performed in Germany with or without cerebral protection devices were extracted from a comprehensive nationwide billing dataset.

RESULTS

A total of 41,654 TAVR procedures performed between 2015 and 2017 were analyzed. The overall share of procedures incorporating cerebral protection devices was 3.8%. Patients receiving cerebral protection devices were at increased operative risk (European System for Cardiac Operative Risk Evaluation score 13.8 vs. 14.7; p < 0.001) but of lower age (81.1 vs. 80.6 years; p = 0.001). To compare outcomes that may be related to the use of cerebral protection devices, a propensity score comparison was performed. The use of a cerebral protection device did not reduce the risk for stroke (adjusted risk difference [aRD]: +0.88%; 95% confidence interval [CI]: -0.07% to 1.83%; p = 0.069) or the risk for developing delirium (aRD: +1.31%; 95% CI: -0.28% to 2.89%; p = 0.106) as a sign of acute brain failure. Although brain damage could not be prevented, in-hospital mortality was lower in the group receiving a cerebral protection device (aRD: -0.76%; 95% CI: -1.46% to -0.06%; p = 0.034).

CONCLUSIONS

In this large national database, cerebral embolic protection devices were infrequently used during TAVR procedures. Device use was associated with lower mortality but not a reduction in stroke or delirium. Future studies are needed to confirm these findings.

Cytokine adsorption in patients with severe COVID-19 pneumonia requiring extracorporeal membrane oxygenation (CYCOV): a single centre, open-label, randomised, controlled trial

Background

We sought to clarify the benefit of cytokine adsorption in patients with COVID-19 supported with venovenous extracorporeal membrane oxygenation (ECMO).

Methods

We did a single-centre, open-label, randomised, controlled trial to investigate cytokine adsorption in adult patients with severe COVID-19 pneumonia requiring ECMO. Patients with COVID-19 selected for ECMO at the Freiburg University Medical Center (Freiburg, Germany) were randomly assigned (1:1) to receive cytokine adsorption using the CytoSorb device or not. Randomisation was computer-generated, allocation was concealed by opaque, sequentially numbered sealed envelopes. The CytoSorb device was incorporated into the ECMO circuit before connection to the patient circuit, replaced every 24 h, and removed after 72 h. The primary endpoint was serum interleukin-6 (IL-6) concentration 72 h after initiation of ECMO analysed by intention to treat. Secondary endpoints included 30-day survival. The trial is registered with ClinicalTrials.gov (NCT04324528) and the German Clinical Trials Register (DRKS00021300) and is closed.

Findings

From March 29, 2020, to Dec 29, 2020, of 34 patients assessed for eligibility, 17 (50%) were treated with cytokine adsorption and 17 (50%) without. Median IL-6 decreased from 357·0 pg/mL to 98·6 pg/mL in patients randomly assigned to cytokine adsorption and from 289·0 pg/mL to 112·0 pg/mL in the control group after 72 h. One patient in each group died before 72 h. Adjusted mean log IL-6 concentrations after 72 h were 0·30 higher in the cytokine adsorption group (95% CI −0·70 to 1·30, p=0·54). Survival after 30 days was three (18%) of 17 with cytokine adsorption and 13 (76%) of 17 without cytokine adsorption (p=0·0016).

Interpretation

Early initiation of cytokine adsorption in patients with severe COVID-19 and venovenous ECMO did not reduce serum IL-6 and had a negative effect on survival. Cytokine adsorption should not be used during the first days of ECMO support in COVID-19.

Funding

None.

Outcome of acute respiratory distress syndrome requiring extracorporeal membrane oxygenation in Covid-19 or influenza: A single-center registry study

Veno‐venous extracorporeal membrane oxygenation (V‐V ECMO) is used to sustain blood oxygenation and decarboxylation in severe acute respiratory distress syndrome (ARDS). It is under debate if V‐V ECMO is as appropriate for coronavirus disease 2019 (Covid‐19) ARDS as it is for influenza. In this retrospective study, we analyzed all patients with confirmed SARS‐CoV‐2 or influenza A/B infection, ARDS and V‐V ECMO, treated at our medical intensive care unit (ICU) between October 2010 and June 2020. Baseline and procedural characteristics as well as survival 30 days after ECMO cannulation were analyzed. A total of 62 V‐V ECMO patients were included (15 with Covid‐19 and 47 with influenza). Both groups had similar baseline characteristics at cannulation. Thirty days after ECMO cannulation, 13.3% of all patients with Covid‐19 were discharged alive from our ICU compared to 44.7% with influenza (P = .03). Patients with Covid‐19 had fewer ECMO‐free days (0 (0‐9.7) days vs. 13.2 (0‐22.1) days; P = .05). Cumulative incidences of 30‐day‐survival showed no significant differences (48.6% in Covid‐19 patients, 63.7% in influenza patients; P = .23). ICU treatment duration was significantly longer in ARDS patients with V‐V ECMO for Covid‐19 compared to influenza. Thirty‐day mortality was higher in Covid‐19, but not significant.

Inhibition of macrophage proliferation dominates plaque regression in response to cholesterol lowering

Statins induce plaque regression characterized by reduced macrophage content in humans, but the underlying mechanisms remain speculative. Studying the translational APOE*3-Leiden.CETP mouse model with a humanized lipoprotein metabolism, we find that systemic cholesterol lowering by oral atorvastatin or dietary restriction inhibits monocyte infiltration, and reverses macrophage accumulation in atherosclerotic plaques. Contrary to current believes, none of (1) reduced monocyte influx (studied by cell fate mapping in thorax-shielded irradiation bone marrow chimeras), (2) enhanced macrophage egress (studied by fluorescent bead labeling and transfer), or (3) atorvastatin accumulation in murine or human plaque (assessed by mass spectrometry) could adequately account for the observed loss in macrophage content in plaques that undergo phenotypic regression. Instead, suppression of local proliferation of macrophages dominates phenotypic plaque regression in response to cholesterol lowering: the lower the levels of serum LDL-cholesterol and lipid contents in murine aortic and human carotid artery plaques, the lower the rates of in situ macrophage proliferation. Our study identifies macrophage proliferation as the predominant turnover determinant and an attractive target for inducing plaque regression.

Cardiogenic shock: incidence, survival and mechanical circulatory support usage 2007-2017-insights from a national registry

Background

A central element in the management of cardiogenic shock (CS) comprises mechanical circulatory support (MCS) systems to maintain cardiac output (CO). This study aims to quantify incidence, outcome and influence of MCS in CS over the last decade.

Methods

All patients hospitalized with CS in a tertiary university hospital in Germany between 2007 and 2017 were identified utilizing the international coding system ICD-10 with code R57.0. Application of MCS was identified via German procedure classification codes (OPS).

Results

383,983 cases of cardiogenic shock were reported from 2007 to 2017. Patients had a mean age of 71 years and 38.5% were female. The incidence of CS rose by 65.6% from 26,828 cases in 2007 (33.1 per 100,000 person-years, hospital survival 39.2%) to 44,425 cases in 2017 (53.7 per 100,000 person-years, survival 41.2%). In 2007, 16.0% of patients with CS received MCS (4.6 per 100,000 person-years, survival 46.6%), dropping to 13.9% in 2017 (6.6 per 100,000 person-years, survival 38.6%). Type of MCS changed over the years, with decreasing use of the intra-aortic balloon pump (IABP), an increase in extracorporeal membrane oxygenation (VA-ECMO) and percutaneous ventricular assist device (pVAD) usage. Significant differences regarding in-hospital survival were observed between the devices (survival: overall: 40.2%; medical treatment = 39.5%; IABP = 49.5%; pVAD = 36.2%; VA-ECMO = 30.5%; p < 0.001).

Conclusions

The incidence of CS is increasing, but hospital survival remains low. MCS was used in a minority of patients, and the percentage of MCS usage in CS has decreased. The use rates of the competing devices change over time.

Graphical Abstract

Electronic supplementary material

The online version of this article (10.1007/s00392-020-01781-z) contains supplementary material, which is available to authorized users.

Bleeding complications drive early mortality of patients with atrial fibrillation after transcatheter aortic valve replacement

Background and objectives

Atrial fibrillation is a risk factor for poor post-operative outcome after transfemoral transcatheter aortic valve replacement (TF-TAVR). The present study analyses the outcomes after TF-TAVR in patients with or without atrial fibrillation (AF) and identifies independent predictors for in-hospital mortality in clinical practice.

Methods and results

Among all 57,050 patients undergoing isolated TF-TAVR between 2008 and 2016 in Germany, 44.2% of patients (n=25,309) had AF. Patients with AF were at higher risk for unfavorable outcome after TAVR. Including all baseline characteristics for a risk-adjusted comparison, AF was an independent risk factor for in-hospital mortality after TAVR. Among patients with AF, EuroSCORE, NYHA class or renal disease had only moderate effects on mortality, while the occurrence of post-procedural stroke substantially increased in-hospital mortality (OR 3.55, 95% CI 2.77–4.56, P&lt;0.001). However, the strongest independent predictor for in-hospital mortality among patients with AF was bleeding (OR 11.04, 95% CI 9.53–12.80, P&lt;0.001). Bleeding also was by far the strongest predictor for prolonged mechanical ventilation (OR 25.36, 95% CI 21.83–29.48, P&lt;0.001).

Conclusions

The present study demonstrates that the incidence of bleeding defines the early outcome of patients with AF after TF-TAVR. Thus, the peri-procedural phase demands particular care in anti-thrombotic regimen.

Funding Acknowledgement

Type of funding source: None

Knockout of purinergic receptor Y13 (P2Y13) results in an improved outcome of metabolic syndrome in mice

 

Metabolic syndrome (MetS) clusters the main risk factors for cardiovascular diseases (CVDs) and endocrine dysfunction. The pathomechanism of MetS is described as local death of hypertrophic adipocytes releasing danger-associated molecular patterns (DAMPs) such as nucleotides (e.g. ADP). This promotes a long term inflammation of adipose tissue via activation of purinergic receptors with a gradual shift towards a pro-inflammatory environment. The ADP receptor P2Y13 is both described in metabolic and immunological processes. These combined characteristics make the P2Y13 an interesting candidate to investigate its role in MetS. Nevertheless, the role of P2Y13R in the pathogenesis of MetS is currently unknown and shall be analyzed in this study.

BMDM isolation and differentiation to Mϕ using M-CSF and subsequent stimulation with medium, LPS and IFNγ or IL4; Expression was quantified using Taqman. Male C57Bl6/J wild-type (WT) and P2Y13-deficient (KO) mice were fed a HFD for 20 weeks; body weight and food consumption were recorded weekly. GTT, ITT and metabolic cages were performed after 15 weeks with euthanization after 20 weeks. In order to distinguish the effect of hematopoetic or somatic cells, mice were lethally irradiated with 9.4Gy and reconstituted with donor bone-marrow (BM) via tail vein injection.

We observed a unique expression of P2Y13R on pro-inflammatory M1 Mϕ. After HFD feeding KO mice showed higher O2 consumption compared to WT mice (AUC of O2 consumption on 2nd day= KO:61620±2261mL/kg vs WT: 53830±916mL/kg, p&lt;0.05). Although KO mice consumed more food compared to WT littermates (KO:5.7±0.5g/d vs WT:3.1±0.1g/d, p&lt;0.0001), they showed significantly decelerated weight gain (e.g.week 15→KO:147,292±5,26% vs WT:180.8±15.9%, p&lt;0.05). Obese KO animals outperformed obese WT littermates in a peritoneal glucose tolerance test (GTT) (2h post-injection (post-i.) →KO:273.7±46.3mg/dL vs WT: 555.0±40.8mg/dL, p&lt;0.05). KO mice on HFD were protected from developing a fatty liver. HFD KO mice receiving WT BM show accelerated weight gain compared to KO mice receiving KO BM (e.g.week 10 WT in KO: 111.2±2.2% vs KO in KO: 102.2±1.2%, p&lt;0.05). In the GTT irradiated KO mice either receiving KO or WT BM are protected from HFD induced impaired glucose homeostasis (45min post-i.; KO→KO:222.1±21.2mg/dL vs WT→KO:232.8±15.9mg/dL vs WT on chow diet:240.4±18.6mg/dL). Contrary, WT mice receiving KO or WT BM developed a glucose resistance comparable to non-irradiated WT mice (45min post-i.; WT→WT:423.8±61.7mg/dL vs KO→WT:434.3±51.1 vs WT on HFD:574.4±7.9).

P2Y13 KO improves the outcome of MetS in mice with improved glucose homeostasis, decelerated weight gain, no fatty liver development and better metabolic turnover. BM transplantation experiments suggest a somatic component as possible explanation of these observations. Given these beneficial metabolic effects, we hypothesize that antagonization of P2Y13R could be a promising therapeutic tool in the field of MetS.

Funding Acknowledgement

Type of funding source: None

P2Y12-dependent regulation of emergency hematopoiesis after myocardial infarction

Introduction

Inflammation is essential for wound healing after myocardial infarction (MI). Leukocytes, especially neutrophils and monocytes, orchestrate removal of necrosis and regulation of tissue remodeling. Beside local recruitment from the blood, leukocyte supply via increased hematopoiesis is of major relevance for post-ischemic myocardial inflammation. Little is known about the pathways that carry the signals for increased demand for leukocytes from the site of injury to upstream hematopoietic stem cells (LSK) in the bone marrow (BM). In this study, we investigate the role of the P2Y12-ADP-receptor mediated regulation for emergency hematopoiesis after MI.

Methods

For standardized MI, a model of permanent coronary ligation was used in C57/Bl6 and P2Y12−/− mice. Changes in plasmatic ADP levels after MI were screened using ELISA, whereas the expression of the P2Y12-ADP-receptor in cell populations isolated from the BM was investigated by qPCR. CFU assays added further functional insight on hematopoietic proliferation in vitro. The effect of P2Y12 on the hematopoietic system after MI was investigated by inhibiting the P2Y12-receptor via prasugrel and compared to inhibition of the thromboxane pathway via acetylsalicylic acid (ASA). Proliferation of LSK in BM and leukocyte composition in blood, BM and infarct tissue after MI were assessed via FACS. Leukocyte composition in the infarcted myocardium was validated by immunohistochemistry. Finally, left ventricular function (LV-EF) and remodeling were investigated by echocardiography.

Results

24 h after MI, we found a peak of plasmatic ADP levels. LSK as upstream hematopoietic progenitors in the BM express a P2Y12-receptor, which was validated on transcriptional and protein level. Whereas ADP stimulation of LSK led to significantly larger colony growth in vitro on the one hand, percentage of cycling LSK were significantly reduced 48 h after MI in P2Y12−/− mice compared to WT mice, assessed by Ki67/DAPI cell cycle analysis. Prasugrel treatment showed similar effects, translating into reduced numbers of downstream hematopoietic progenitors GMP and MDP 72 h after MI. Treatment with ASA however had no significant effect neither on cycling LSK nor progenitor populations. Consequently, decreased medullary hematopoiesis under P2Y12-inhibition led to reduced infiltration of inflammatory cells in the infarct tissue 7 days after MI, finally resulting in significantly improved outcome in terms of LV-EF 3 weeks after MI.

Conclusion

In this study, we demonstrate that P2Y12-mediated signaling is involved in emergency hematopoiesis after MI and advocates post-MI inflammation. In turn, inhibition of P2Y12-mediated signaling contributes to improved wound healing and prevention of adverse cardiac remodeling after MI, which adds a yet unknown mechanism to the success story of modern P2Y12-receptor blockers.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft

Atlas of the immune cell repertoire in human atherosclerotic plaques characterized by single cell RNA-sequencing and multi-color flow cytometry

Rationale

Atherosclerosis is a chronic inflammatory disease that is driven by the accumulation of pro- and anti-inflammatory leukocytes in the intima of affected arteries. Yet, the cellular composition of human atherosclerotic plaques is only poorly understood. Here, we characterized immune cells to human carotid atherosclerotic plaques by multi-color flow cytometry and scRNAseq.

Methods and results

First, we compared a set of previously reported digestion protocols to liberate leukocytes from human carotid plaques after surgical thrombendarteriectomy. One digestion cocktail, containing Collagenase IV and DNase I, was superior regarding cell survival and cell surface marker preservation. Second, leukocytes from 56 surgical specimen were characterized by flow cytometry with a set of 16 parameters and cell surface markers capable of identifying principal hematopoietic leukocyte lineages. This protocol allowed to extract and analyze on average 4x103 viable CD45+ leukocytes from a mean of 988 mg plaque tissue. Surprisingly, we found that atherosclerotic plaques were dominated by T cells with 33.7±2.2% CD4+ T-helper cells and 25.6±2.5% CD8+ cytotoxic T cells. CD11b+ myeloid cells, including monocytes and macrophages, represented only 20.2±4.0% of all CD45+ leukocytes. CD19+B cells and CD56+ NK-cells accounted for 3.9±1.2 and 3.3±0.5%, respectively. TCR-g/d+ T cells and neutrophils were undetectable in atherosclerotic plaques. This cellular composition differed significantly from peripheral blood, but was not relevantly changed between different plaque locations, indicating that macrophage-rich necrotic cores mostly contain dead cells. We confirmed the principal composition of human plaques by single-cell RNA-sequencing from six patients. To allow an estimation of cellular heterogeneity independent of classical cell surface marker assignment, we performed an unsupervised cluster detection algorithm by t-distributed stochastic neighbor embedding (tSNE) and found more than 16 leukocyte clusters with unique cell surface marker expression, suggesting an unexpected high diversity of plaque leukocytes.

Conclusion

We developed an immune cell phenotyping protocol optimized for human carotid plaques. The definition of phenotypes and frequencies in atherosclerotic plaques will allow to build clinical associations between the immune cell composition and clinical outcomes in future.

Funding Acknowledgement

Type of funding source: None

Macrophage-specific IRF5 deficiency stabilizes atherosclerotic plaques in ApoE−/− mice

Background

Interferon regulatory factor (IRF) 5 is a transcription factor promoting inflammatory macrophage polarization (M1 type). Given the central role of macrophages in atherosclerotic plaque development we hypothesized that macrophage specific deletion of IRF5 will protect from atherosclerosis.

Purpose

Investigate whether intrinsic blockade of M1 macrophage polarization ameliorates atherosclerosis

Methods

Female ApoE−/−LysMCre/wtIRF5flox/floxand ApoE−/−LysMwt/wtIRF5flox/floxmice were fed a high cholesterol diet for 3 months, and atherosclerotic plaque size and compositions as well as inflammatory gene expression were analyzed. Mechanistically, IRF5-dependend bone marrow derived macrophage cytokine profiles were tested under M1 and M2 polarizing conditions. Aortic macrophage chimerism in irradiated ApoE−/− mice reconstituted with a mixture of CD45.1+ ApoE−/− (WT) and CD45.2+ ApoE−/− LysMCre/WtIRF5flox/flox(KO) bone marrow was evaluated to distinguish systemic from intra-plaque effects on monocyte/macrophage kinetics.

Results

Macrophage-specific IRF5 deficiency blunted LPS/IFNg-induced IL-1β and TNFα gene expression in vitro. In ApoE−/− mice, macrophage-specific IRF5 deficiency did not alter lesion size in the aortic root but significantly reduced macrophage and lipid contents by about 25% while increasing collagen deposition by over 30%. This was accompanied by relative reductions in gene expressions of pro-inflammatory (IL-1β, IL-6, IL-12) and increases in anti-inflammatory (Mertk, TGFβ, CD206) markers in atherosclerotic aortas of ApoE−/−LysMCre/wtIRF5flox/floxmice. When competing with IRF5 deficient cells in mixed irradiation bone marrow chimeras, IRF5 competent macrophages showed an advantage in accumulating in atherosclerotic aortas as disease progressed independent of monocyte recruitment.

Conclusion

Transcription factor IRF5 promotes a pro-inflammatory response in macrophages leading to vulnerable plaque formation and plaque destabilization, providing genetic evidence for targeting macrophage polarization in atherosclerosis.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): DFG

Deficiency of the purinergic receptor P2X4 limits atherosclerosis in mice

Introduction

Extracellular nucleotides like ATP promote inflammation as danger signals in various chronic diseases via purinergic receptors. In our previous work we identified P2X4 expression in murine atherosclerotic lesions. Therefore, we hypothesized a contribution of the ATP-P2X4 axis to vascular inflammation in atherosclerosis.

Methods

To investigate the functional role of P2X4 in atherogenesis, wild-type LDL-receptor deficient mice (LDLR−/−) and P2X4-deficient LDLR−/− mice (P2X4−/−LDLR−/−) were fed a high cholesterol diet for 16 weeks. Plaque progression in aortic arches was monitored by echography at intervals of 4 weeks, and leukocyte subsets in blood samples were analysed by flow cytometry. Atherosclerotic lesions were then assessed histologically in aortic root, arch, and abdominal aorta. In order to assess leukocyte recruitment, intravital microscopy was performed after injection of ATP in P2X4−/− or wildtype mice (WT). Regarding transferability to human disease, atherosclerotic plaque from carotid endarterectomy has been stained immunohistochemically for P2X4-receptor expression.

Results

After 16 weeks, P2X4-deficient mice showed significantly reduced atherosclerotic lesions in the aortic root (n=40, LDLR−/−: 0.47 mm2, P2X4−/−LDLR−/−: 0.39 mm2, p=0.04). Ly6C- monocyte count in peripheral blood was higher in P2X4−/−LDLR−/− (n=32, LDLR−/−: 241/μl, P2X4−/−LDLR−/−: 542/μl, p=0.0088), shifting the balance to a more anti-inflammatory subset. Memory-cell generation of CD4-T-cells is significantly higher in knockout-mice, suggesting an involvement of T-helper cells (n=25, LDLR−/−: 27%, P2X4−/−LDLR−/−: 46%, p=0.0003). Peritoneally injected ATP induced leukocyte rolling in WT, but not in P2X4-deficient mice. In human carotid arteries, atherosclerotic plaque shows higher staining for P2X4−/− receptor than not diseased areas.

Conclusion

P2X4-deficiency enhances anti-inflammatory leukocytes in peripheral blood and reduces atherosclerosis. Therefore, blocking the ATP-P2X4 axis may prevent leukocyte recruitment to atherosclerotic lesions and could present a potential new target for anti-atherogenic therapy.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This work was supported by a research grant of the German Research Foundation (DFG) to Peter Stachon. Sebastian König was supported by a research grant of the German Cardiac Society (DGK)

Use and outcomes of emergency treatment strategies in patients with aortic valve stenosis

Introduction and aim

Current emergency treatment options for severe aortic valve stenosis include surgical aortic valve replacement (SAVR), transcatheter aortic valve replacement (TAVR) and balloon valvuloplasty (BV). So far no larger patient population has been evaluated regarding clinical characteristics and outcomes. Therefore we aimed to describe the use and outcome of the three therapy options in a broad registry study.

Method and results

Using German nationwide electronic health records, we evaluated emergency admissions of symptomatic patients with severe aortic valve stenosis between 2014 and 2017. Patients were grouped according to SAVR, TAVR or BV only treatments. Primary outcome was in-hospital mortality. Secondary outcomes were stroke, acute kidney injury, periprocedural pacemaker implantation, delirium and prolonged mechanical ventilation &gt;48 hours. Stepwise multivariable logistic regression analyses including baseline characteristics were performed to assess outcome risks.

8,651 patients with emergency admission for severe aortic valve stenosis were identified. The median age was 79 years and comorbidities included NYHA classes III-IV (52%), coronary artery disease (50%), atrial fibrillation (41%) and diabetes mellitus (33%). Overall in-hospital mortality was 6.2% during a mean length of stay of 22±15 days. TAVR was the most common treatment (6,357 [73.5%]), followed by SAVR (1,557 [18%]) and BV (737 8.5%]).

Patients who were treated with TAVR or BV were significantly older than patients with SAVR (mean age 81.3±6.5 and 81.2±6.9 versus 67.2±11.0 years, p&lt;0.001), had more relevant comorbidities (coronary artery disease 52–91% vs. 21.8%; p&lt;0.001), worse NYHA classes III-IV (55–65% vs. 34.5%; p&lt;0.001) and higher EuroSCORES (24.6±14.3 and 23.4±13.9 vs. 9.5±7.6; p&lt;0.001) than SAVR patients. Patients treated with BV only had the highest in-hospital mortality compared with TAVR or SAVR (20.9% vs. 5.1 and 3.5%; p&lt;0.001).

Compared with BV only, SAVR patients (adjusted odds ratio [aOR] 0.25; 95% confidence interval [CI] 0.14–0.46; p&lt;0.001) and TAVR patients (aOR 0.37; 95% CI 0.28–0.50; p&lt;0.001) had a lower risk for in-hospital mortality.

Conclusion

In-hospital mortality for emergency patients with symptomatic severe aortic valve stenosis is high. Our results showed that BV only therapy was associated with highest mortality, which is in line with current research. Yet, there is a trend towards more TAVR interventions and this study might imply that balloon valvuloplasty alone is insufficient. The role of BV as a bridging strategy to TAVR or SAVR needs to be further investigated.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Heart Center Freiburg University, Department of Cardiology and Angiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany

Hospital volumes and the likelihood of stent implantation among patients undergoing catheterization of the left heart: more is more?

Background

Percutaneous coronary intervention (PCI) is an established procedure, but recent studies analyzing the indication for stenting are going to change clinical practice. Previous studies suggested that hospital volume is inversely related to in-hospital mortality but its impact on likelihood of stent implantation and the number of stents remains unclear.

Purpose

There is a conflict of objectives between nationwide care including short transfer and intervention times and a few large centers with maximum technology and experience. We examine the effect of hospital volume on in-hospital mortality, likelihood of stent implantation, number of stents, length of hospital stay, and reimbursement in a recent nationwide cohort from Germany.

Methods

Using German national electronic health records, all patients who underwent coronary angiography with a documented coronary artery disease were identified by ICD and OPS codes. Risk-adjustment was applied using a predefined set of patient characteristics to account for differences in the risk factor composition of the patient populations between centers.

Results

In 2017, a total of 528,188 patients with a documented coronary artery disease underwent coronary angiography in Germany. Mean age was 69.8 years and 29.3% of patients were female. 55% of all patients received PCI, with a mean number of 1.01 stents implanted per patient. In-hospital mortality was 2.9%, length of hospital stay was 6.5 days and mean reimbursement was €5,531. Multivariable regression analyses showed a positive linear association between hospital volumes and the likelihood of stent implantation (p=0.003) as well as the number of implanted stents (p=0.020). No association was found between hospital volumes and in-hospital mortality (p=0.105), length of hospital stay (p=0.201) or reimbursement (p=0.108). Inspection of the non-linear impact of procedure volumes on stent implantation practices indicates a ceiling effect in the volume-outcome relationship: implantation likelihood and number of stents per patient are lowest in centers with less than 100 procedures per year (34.4% and 0.62, respectively). Then, implantation likelihood and number of stents constantly increase until the volume category of 500 procedures per year and center. For centers with &gt;500 procedures per year, the likelihood of stent implantation and the number of implanted stents remained relatively constant (about 60% and 1.07, respectively).

Conclusion

Patients undergoing coronary angiography in low-volume centers are less frequently subject to PCI but at comparable risk for in-hospital mortality. Furthermore, the data suggest that more complex cases are treated in high volume centers with consistent mortality rates and thus constant safety is ensured in high volume hospitals. Thresholds are discussed.

Impact of hospital volumes on PCI

Funding Acknowledgement

Type of funding source: None

Impact of Preprocedural Aortic Valve Calcification on Conduction Disturbances after Transfemoral Aortic Valve Replacement

AIM

The present study analyzes in depth the impact of different calcification patterns on disturbances of the conduction system in transcatheter aortic valve replacement (TAVR) patients.

METHODS AND RESULTS

A total of 169 preprocedural TAVR multislice computed tomography scans from consecutive transfemoral (TF) TAVRs performed between 2014 and 2017 using either Edwards SAPIEN or Medtronic Evolut R valves were retrospectively evaluated. The volume, distribution, and orientation of annular and valvular aortic valve calcification were measured and their impact on postoperative conduction disturbances was determined using linear and logistic regression analyses. The total volume of calcification and distribution at the aortic annulus or valve did not influence the conduction system. Oval calcification of the left aortic cusp was independently associated with an elevated risk for an increase in atrioventricular block degree (+0.6, p = 0.03). Moreover, orthogonal calcifications at the level of the aortic annulus were associated with an increased risk for QRS prolongation (+26 ms, p = 0.004) and an increased risk for permanent pacemaker implantation (OR 4.3, p = 0.03) after TF TAVR. This was more pronounced in patients undergoing TF TAVR using a balloon-expandable Edwards SAPIEN 3 valve (QRS +38.195 ms, p < 0.001; OR permanent pacemaker 15.48, p = 0.013).

CONCLUSION

Orthogonal annular calcification confers an increased risk for conduction disturbances after TAVR. This is even more pronounced after implantation of balloon-expandable valves.

Bleeding Complications Drive In-Hospital Mortality of Patients with Atrial Fibrillation after Transcatheter Aortic Valve Replacement

Background Atrial fibrillation (AF) is a risk factor for poor postoperative outcome after transfemoral transcatheter aortic valve replacement (TF-TAVR). The present study analyses the outcomes after TF-TAVR in patients with or without AF and identifies independent predictors for in-hospital mortality in clinical practice.

Methods and Results Among all 57,050 patients undergoing isolated TF-TAVR between 2008 and 2016 in Germany, 44.2% of patients (n = 25,309) had AF. Patients with AF were at higher risk for unfavorable in-hospital outcome after TAVR. Including all baseline characteristics for a risk-adjusted comparison, AF was an independent risk factor for in-hospital mortality after TAVR. Among patients with AF, EuroSCORE, New York Heart Association classification class, or renal disease had only moderate effects on mortality, while the occurrence of postprocedural stroke or moderate to major bleeding substantially increased in-hospital mortality (odds ratio [OR] 3.35, 95% confidence interval [CI] 2.61–4.30, p < 0.001 and OR 3.12, 95% CI 2.68–3.62, p < 0.001). However, the strongest independent predictor for in-hospital mortality among patients with AF was severe bleeding (OR 18.00, 95% CI 15.22–21.30, p < 0.001).

Conclusion The present study demonstrates that the incidence of bleeding defines the in-hospital outcome of patients with AF after TF-TAVR. Thus, the periprocedural phase demands particular care in bleeding prevention.

Molecular magnetic resonance imaging of activated platelets allows noninvasive detection of early myocarditis in mice

MRI sensitivity for diagnosis and localization of early myocarditis is limited, although it is of central clinical interest. The aim of this project was to test a contrast agent targeting activated platelets consisting of microparticles of iron oxide (MPIO) conjugated to a single-chain antibody directed against ligand-induced binding sites (LIBS) of activated glycoprotein IIb/IIIa (= LIBS-MPIO). Myocarditis was induced by subcutaneous injection of an emulsion of porcine cardiac myosin and complete Freund’s adjuvant in mice. 3D 7 T in-vivo MRI showed focal signal effects in LIBS-MPIO injected mice 2 days after induction of myocarditis, whereas in control-MPIO injected mice no signal was detectable. Histology confirmed CD41-positive staining, indicating platelet involvement in myocarditis in mice as well as in human specimens with significantly higher LIBS-MPIO binding compared to control-MPIO in both species. Quantification of the myocardial MRI signal confirmed a signal decrease after LIBS-MPIO injection and significant less signal in comparison to control-MPIO injection. These data show, that platelets are involved in inflammation during the course of myocarditis in mice and humans. They can be imaged non-invasively with LIBS-MPIO by molecular MRI at an early time point of the inflammation in mice, which is a valuable approach for preclinical models and of interest for both diagnostic and prognostic purposes.

Pathogenic Autoimmunity in Atherosclerosis Evolves From Initially Protective Apolipoprotein B100-Reactive CD4+ T-Regulatory Cells

BACKGROUND

Throughout the inflammatory response that accompanies atherosclerosis, autoreactive CD4⁺ T-helper cells accumulate in the atherosclerotic plaque. Apolipoprotein B₁₀₀ (apoB), the core protein of low-density lipoprotein, is an autoantigen that drives the generation of pathogenic T-helper type 1 (T_H1) cells with proinflammatory cytokine secretion. Clinical data suggest the existence of apoB-specific CD4⁺ T cells with an atheroprotective, regulatory T cell (T_reg) phenotype in healthy individuals. Yet, the function of apoB-reactive T_regs and their relationship with pathogenic T_H1 cells remain unknown.

METHODS

To interrogate the function of autoreactive CD4⁺ T cells in atherosclerosis, we used a novel tetramer of major histocompatibility complex II to track T cells reactive to the mouse self-peptide apo B_978-993 (apoB⁺) at the single-cell level.

RESULTS

We found that apoB⁺ T cells build an oligoclonal population in lymph nodes of healthy mice that exhibit a T_reg-like transcriptome, although only 21% of all apoB⁺ T cells expressed the T_reg transcription factor FoxP3 (Forkhead Box P3) protein as detected by flow cytometry. In single-cell RNA sequencing, apoB⁺ T cells formed several clusters with mixed T_H signatures that suggested overlapping multilineage phenotypes with pro- and anti-inflammatory transcripts of T_H1, T helper cell type 2 (T_H2), and T helper cell type 17 (T_H17), and of follicular-helper T cells. ApoB⁺ T cells were increased in mice and humans with atherosclerosis and progressively converted into pathogenic T_H1/T_H17-like cells with proinflammatory properties and only a residual T_reg transcriptome. Plaque T cells that expanded during progression of atherosclerosis consistently showed a mixed T_H1/T_H17 phenotype in single-cell RNA sequencing. In addition, we observed a loss of FoxP3 in a fraction of apoB⁺ T_regs in lineage tracing of hyperlipidemic Apoe^-/- mice. In adoptive transfer experiments, converting apoB⁺ T_regs failed to protect from atherosclerosis.

CONCLUSIONS

Our results demonstrate an unexpected mixed phenotype of apoB-reactive autoimmune T cells in atherosclerosis and suggest an initially protective autoimmune response against apoB with a progressive derangement in clinical disease. These findings identify apoB autoreactive T_regs as a novel cellular target in atherosclerosis.

Prone positioning in severe ARDS requiring extracorporeal membrane oxygenation

Background

Prone positioning (PP) has shown to improve survival in patients with severe acute respiratory distress syndrome (ARDS). To this point, it is unclear if PP is also beneficial for ARDS patients treated with veno-venous extracorporeal membrane oxygenation (VV ECMO) support.

Methods

We report retrospective data of a single-centre registry of patients with severe ARDS requiring VV ECMO support between October 2010 and May 2018. Patients were allocated to the PP group if PP was performed during VV ECMO treatment or the supine positioning group. VV ECMO weaning success and hospital survival were analysed before and after propensity score matching.

Results

A total of 158 patients could be analysed, and 38 patients (24.1%) received PP. There were no significant differences in VV ECMO weaning rate (47.4% vs. 46.7%, p = 0.94) and hospital survival (36.8% vs. 36.7%, p = 0.98) between the prone and supine groups, respectively. The analysis of 38 propensity score matched pairs also showed no difference in hospital survival (36.8% vs. 36.8%, p = 1.0) or VV ECMO weaning rate (47.4% vs. 44.7%, p = 0.82). Hospital survival was superior in the subgroup of patients treated with early PP (cutoff < 17 h via Youden’s Index) as compared to late or no PP (81.8% vs. 33.3%, p = 0.02).

Conclusion

In this propensity score matched cohort of severe ARDS patients requiring VV ECMO support, prone positioning at any time was not associated with improved weaning or survival. However, early initiation of prone positioning was linked to a significant reduction of hospital mortality.