Changes in thromboinflammatory profiles across the generations of transcatheter aortic heart valves

Acquired Thrombocytopenia in Contemporary Transcatheter Aortic Valve Prosthesis

BACKGROUND

 Postprocedural thrombocytopenia is a known phenomenon following transcatheter aortic valve implantation (TAVI). The aim of this study is to evaluate whether postinterventional platelet kinetics differ when comparing the current generation of balloon-expandable valve (BEV) and self-expanding valve (SEV) prostheses.

METHODS

 We performed a retrospective analysis of patients undergoing TAVI at our facility between 2017 and 2019. Patients were stratified according to the type of prosthesis used: BEV or SEV. Hematocrit-corrected platelet counts were calculated to account for dilution. Nadir platelet counts (lowest recorded platelet count), drop platelet counts (DPC; highest relative platelet drop from baseline), and severity of thrombocytopenia during the discourse and at discharge were assessed.

RESULTS

 Of the 277 included patients, 212 received SEV and 65 BEV. BEV patients were younger (81.8 ± 4.4 years vs 79.7 ± 6.8 years, p = 0.03). Further demographic characteristics were similar between groups. Implanted SEV were larger (p < 0.001) and had shorter procedural times (p < 0.01). There were no significant differences in postprocedural discourse. Postinterventional platelet drop was more pronounced in BEV patients in several evaluated metrics: mean DPC (24.3 ± 10.9% vs 18.8 ± 14.8%, p < 0.01), patients with DPC > 30% (n = 19, 29.2%, vs n = 33, 15.6%, p = 0.02), and also when comparing platelet kinetics.

CONCLUSION

 Despite improvements in outcome, the current generation of balloon-expandable TAVI prostheses carries a predisposition for postprocedural thrombocytopenia even when the effects of dilution are accounted for.

Predictive potential of pre-procedural cardiac and inflammatory biomarkers regarding mortality following transcatheter aortic valve implantation: A systematic review and meta-analysis

BACKGROUND

Aortic stenosis (AS) is a common heart valve disease, especially in aging populations. While surgical aortic valve replacement (SAVR) is the standard treatment, many patients are ineligible. Transcatheter aortic valve implantation (TAVI) offers an alternative, especially for high-risk patients, but is not without complications. Identifying biomarkers that predict post-TAVI mortality is essential for optimizing outcomes.

OBJECTIVES

The purpose of this systematic review and meta-analysis is to evaluate the role of cardiac and inflammatory biomarkers in predicting short-term and mid to long-term mortality following TAVI.

METHODS

We searched PubMed, Scopus, Embase, and Web of Science for studies examining the impact of inflammatory and cardiac biomarkers on mortality following TAVI. Mean differences (MDs) and 95 % confidence interval (CI) were calculated using a random-effect model.

RESULTS

Twenty-eight studies involving 10,560 patients were included, with 1867 in the mortality group. Mortality was significantly associated with higher pre-procedural levels of creatinine (0.41; 95 % CI: [0.35, 0.48]), brain natriuretic peptide (0.58; 95 % CI: [0.43, 0.73]), C-reactive protein (0.55; 95 % CI: [0.45, 0.64]), and white blood cell count (0.18; 95 % CI: [0.06, 0.31]), and lower pre-procedural levels of hemoglobin (-0.49; 95 % CI: [-0.60, -0.38]) and albumin (-0.18; 95 % CI: [-0.24, -0.13]). These associations remained statistically significant in subgroup analyses for both mid to long-term mortality and short-term mortality, except for WBC levels, which were not significantly associated with short-term mortality, and Hb, for which short-term data were insufficient. Platelet count showed no significant difference.

CONCLUSION

These findings highlight the importance of inflammatory and cardiac biomarkers in risk stratification and patient management in TAVI procedures.

Thrombocytopenia Complicating Transcatheter Aortic Valve Implantation: Differences Between Two New-Generation Devices

Thrombocytopenia after TAVI is common and clinically detrimental. Retrospectively, we observed Portico recipients had a more profound platelet drop than Evolut recipients. We thus investigated periprocedural platelet damage and/orpro-inflammatory state in 64 TAVI recipients at baseline and after implantation. Platelet damage was assessed by annexin V staining and monocyte-phagocytic phenotype was assessed according to CD14/CD36 expression. Serum cytokines were measured in 20 patients. The formaldehyde-based storage solution altered platelets. When, before being loaded onto the delivery system, Portico underwent one additional flushing to those recommended, the receiving patients showed thrombocytopenia, platelet damage, and CD36-monocyte count were mitigated. A general increase in IL-6 was recorded in overall TAVI recipients, but a high serum level of IL-8, a potent thrombocytopenia inducer, was measured in Portico recipients only, including those with extra-rinsed valve. Our study suggests a platelet-injury effect by storage-solution and generates the hypothesis of a role for the biomaterial in stimulating innate-immunity. Larger prospective studies are needed. Graphical Abstract.

Transcatheter aortic valve thrombosis: a review of potential mechanisms

Transcatheter aortic valve (TAV) thrombosis has been recognized as a significant problem that sometimes occurs as early as within 30 days after valve implantation, leading to increased concerns of stroke and long-term valve durability. In this article, a critical summary of the relevant literature on identifying potential mechanisms of TAV thrombosis from the perspective of the well-known Virchow's triad, which comprises blood flow, foreign materials and blood biochemistry, is presented. Blood flow mechanisms have been the primary focus thus far, with a general consensus on the flow mechanisms with respect to haemodynamic conditions, the influence of TAV placement and expansion and the influence of coronary flow. Less attention has been paid to the influence of blood biochemistry and foreign materials (and related endothelial damage), with little consensus among studies with regards to platelet and/or microparticle levels post-TAV implantation. Finally, we discuss the future outlook for research with unanswered scientific questions.

Clinical features and significance of leukopenia occurring immediately after endovascular surgery

PURPOSE

Inflammation after stent graft surgery is known as postimplantation syndrome (PIS) and it causes leukocytosis. However, we have experienced leukopenia in the very early postoperative phase of endovascular surgery at our institution. We investigated leukopenia, an under-recognized phenomenon that occurred after transcatheter aortic valve implantation (TAVI), endovascular aortic repair (EVAR), and thoracic endovascular aortic repair (TEVAR).

METHODS

Records of patients who underwent TAVI, EVAR, and TEVAR between March 2018 and February 2019 were retrospectively reviewed. Primary outcomes were the decline rate of white blood cell count (DR-WBC) in the immediate postoperative period and its differences among surgical procedures. The secondary endpoint was the relationship between DR-WBC and infectious complications. Furthermore, the incidence of PIS and its differences among the procedures and associations with DR-WBC were evaluated.

RESULTS

A total of 108 patients (TAVI 41, EVAR 37, TEVAR 30) were included. DR-WBC immediately after surgery was higher in the TAVI group when compared with other groups (TAVI, 43.1 ± 22.6%; EVAR, 27.6 ± 17.3%; TEVAR, 25.4 ± 27.4%; P < 0.01). DR-WBC was not significantly different regardless of postoperative infection (P = 0.45) or PIS (P = 0.62). The incidence rate of PIS was higher in the EVAR group compared with the TAVI group, and was not associated with DR-WBC.

CONCLUSIONS

Leukopenia was a common phenomenon immediately after endovascular surgery, especially TAVI. It resolved a day after surgery and was not associated with PIS or infectious complications. Therefore, it seems to be a transient abnormal hematological finding and a self-limiting condition.

Transcatheter aortic valve replacement during the COVID-19 pandemic-A Dutch single-center analysis

BACKGROUND AND AIM OF THE STUDY

The coronavirus disease 2019 (COVID-19) pandemic has put an enormous strain on healthcare systems and intensive care unit (ICU) capacity, leading to suspension of most elective procedures, including transcatheter aortic valve replacement (TAVR). However, deferment of TAVR is associated with significant wait-time mortality in patients with severe aortic valve stenosis. Conversely, there is currently no data available regarding the safety and feasibility of a continued TAVR program during this unprecedented crisis. The aim of this study is to evaluate the safety and feasibility of patients undergoing TAVR during the COVID-19 pandemic in our center, with specific emphasis on COVID-19 related outcomes.

METHODS

All patients who underwent TAVR in our center between February 27, 2020, and June 30, 2020, were evaluated. Clinical outcomes were described in terms of Valve Academic Research Consortium 2 definitions. Patient follow-up was done by chart review and telephone survey.

RESULTS

A total of 71 patients have undergone TAVR during the study period. Median age was 80 years, 63% were men, and 25% were inpatients. Procedural success was 99%. After TAVR, 30% involved admission to the ICU, and 94% were ultimately discharged to the cardiac care unit on the same day. Two patients (3%) had confirmed COVID-19 a few days after TAVR, and both died of COVID-19 pneumonia within 2 weeks after hospital discharge.

CONCLUSIONS

A continued TAVR program during the COVID-19 pandemic is feasible despite limited hospital resources. However, COVID-19 related mortality after TAVR is of concern.

Subtype of atrial fibrillation and the outcome of transcatheter aortic valve replacement: The FinnValve Study

Whether the subtype of atrial fibrillation affects outcomes after transcatheter aortic valve replacement for aortic stenosis is unclear. The nationwide FinnValve registry included 2130 patients who underwent primary after transcatheter aortic valve replacement for aortic stenosis during 2008-2017. Altogether, 281 (13.2%) patients had pre-existing paroxysmal atrial fibrillation, 651 (30.6%) had pre-existing non-paroxysmal atrial fibrillation and 160 (7.5%) were diagnosed with new-onset atrial fibrillation during the index hospitalization. The median follow-up was 2.4 (interquartile range: 1.6-3.8) years. Paroxysmal atrial fibrillation did not affect 30-day or overall mortality (p-values >0.05). Non-paroxysmal atrial fibrillation demonstrated an increased risk of overall mortality (hazard ratio: 1.61, 95% confidence interval: 1.35-1.92; p<0.001), but not 30-day mortality (p = 0.084). New-onset atrial fibrillation demonstrated significantly increased 30-day mortality (hazard ratio: 2.76, 95% confidence interval: 1.25-6.09; p = 0.010) and overall mortality (hazard ratio: 1.68, 95% confidence interval: 1.29-2.19; p<0.001). The incidence of early or late stroke did not differ between atrial fibrillation subtypes (p-values >0.05). In conclusion, non-paroxysmal atrial fibrillation and new-onset atrial fibrillation are associated with increased mortality after transcatheter aortic valve replacement for aortic stenosis, whereas paroxysmal atrial fibrillation has no effect on mortality. These findings suggest that non-paroxysmal atrial fibrillation rather than paroxysmal atrial fibrillation may be associated with structural cardiac damage which is of prognostic significance in patients with aortic stenosis undergoing transcatheter aortic valve replacement.

Effect on Mortality of Systemic Thromboinflammatory Response After Transcatheter Aortic Valve Implantation

After transcatheter aortic valve implantation (TAVI) there is consistently identified decrease in platelets accompanied by a leucocyte (white blood cell, WBC) increase. We aimed to analyze the prognostic value of early platelet and WBC count changes (thromboinflammatory response) after successful TAVI. Among 432 consecutive patients [median 83.0 years of age, 63.4% women], platelets and WBCs were measured before and for 7 days post-TAVI. Follow-up was 36.9 (21.4 to 48.0) months. Platelet decrease (∆%Platelet-max) and parallel WBC increase (∆%WBC-max) were seen at days 1 to 3. Both ∆%Platelet-max ≤-37.6% and ∆%WBC-max >72.5% predicted mortality (area under the curve = 0.569 and area under the curve = 0.626). The 30-day and 1-year mortality (13.1% and 26.2%) were highest among 28% patients with a greater decrease in platelets and a greater increase in WBCs; intermediate (0.9% and 12.3%) among 52.5% patients with either a greater decrease in platelets or a greater increase in WBCs, but not both; and lowest (0% and 6.6%) among 19.5% patients with a lesser decrease in platelets and a lesser increase in WBCs (p <0.001). Estimated 4-year mortality rates were 53.7% versus 36.2% versus 24.5%, respectively, p <0.001. Bleeding, surgical wounds, acute kidney, and brain injury predicted a more intense thromboinflammatory response, whereas use of the newer generations had the opposite effect. In conclusion, substantial thromboinflammatory response identified after successful TAVI predicts a higher long-term mortality.

Lipoprotein(a) as Orchestrator of Calcific Aortic Valve Stenosis

Aortic valve stenosis (AVS) is the most prevalent valvular heart disease in the Western World with exponentially increased incidence with age. If left untreated, the yearly mortality rates increase up to 25%. Currently, no effective pharmacological interventions have been established to treat or prevent AVS. The only treatment modality so far is surgical or transcatheter aortic valve replacement (AVR). Lipoprotein(a) [Lp(a)] has been implicated as a pivotal player in the pathophysiology of calcification of the valves. Patients with elevated levels of Lp(a) have a higher risk of hospitalization or mortality due to the presence of AVS. Multiple studies indicated Lp(a) as a likely causal and independent risk factor for AVS. This review discusses the most important findings and mechanisms related to Lp(a) and AVS in detail. During the progression of AVS, Lp(a) enters the aortic valve tissue at damaged sites of the valves. Subsequently, autotaxin converts lysophosphatidylcholine in lysophosphatidic acid (LysoPA) which in turn acts as a ligand for the LysoPA receptor. This triggers a nuclear factor-κB cascade leading to increased transcripts of interleukin 6, bone morphogenetic protein 2, and runt-related transcription factor 2. This progresses to the actual calcification of the valves through production of alkaline phosphatase and calcium depositions. Furthermore, this review briefly mentions potentially interesting therapies that may play a role in the treatment or prevention of AVS in the near future.