Implementing screening for myocardial injury in non-cardiac surgery: perspectives of an ad-hoc interdisciplinary expert group

Objectives. Perioperative myocardial injury (PMI) is increasingly recognised as an important complication of non-cardiac surgery, with often clinically silent presentation, but detrimental prognosis. Active screening for PMI, involving the detection of dynamic and elevated levels of cardiac troponin, has recently been advocated by an increasing number of guidelines; however, active PMI screening has not been reflected in clinical practice. Design. As consensus on a common screening and management pathway is lacking, we synthesise the current evidence to provide suggestions on the selection of patients for screening, organisation of a screening program, and a potential management pathway, building upon a recently published perioperative screening algorithm. Results. Screening should be performed using high-sensitivity assays both preoperatively and postoperatively (postoperative Days 1 and 2) in patients at high-risk of experiencing perioperative complications. Conclusion. This expert opinion piece by an interdisciplinary group of predominantly Norwegian clinicians aims to assist healthcare professionals planning to implement guideline-recommended PMI screening at a local level in order to improve patient outcomes following non-cardiac surgery.

Cytokine pattern in patients with ST-elevation myocardial infarction treated with the interleukin-6 receptor antagonist tocilizumab

BACKGROUND

Tocilizumab improves myocardial salvage index (MSI) in patients with ST-elevation myocardial infarction (STEMI), but its mechanisms of action are unclear. Here, we explored how cytokines were affected by tocilizumab and their correlations with neutrophils, C-reactive protein (CRP), troponin T, MSI and infarct size.

METHODS

STEMI patients were randomised to receive a single dose of 280 mg tocilizumab (n=101) or placebo (n=98) before percutaneous coronary intervention. Blood samples were collected before infusion of tocilizumab or placebo at baseline, during follow-up at 24-36, 72-168 hours, 3 and 6 months. 27 cytokines were analysed using a multiplex cytokine assay. Cardiac MRI was performed during hospitalisation and 6 months.

RESULTS

Repeated measures analysis of variance showed significant (p<0.001) between-group difference in changes for IL-6, IL-8 and IL-1ra due to an increase in the tocilizumab group during hospitalisation. IL-6 and IL-8 correlated to neutrophils in the placebo group (r=0.73, 0.68, respectively), which was attenuated in the tocilizumab group (r=0.28, 0.27, respectively). A similar pattern was seen for MSI and IL-6 and IL-8 in the placebo group (r=-0.29, -0.25, respectively) in patients presenting ≤3 hours from symptom onset, which was attenuated in the tocilizumab group (r=-0.09,-0.14, respectively).

CONCLUSIONS

Tocilizumab increases IL-6, IL-8 and IL-1ra in STEMI. IL-6 and IL-8 show correlations to neutrophils/CRP and markers of cardiac injury in the placebo group that was attenuated in the tocilizumab group. This may suggest a beneficial effect of tocilizumab on the ischaemia-reperfusion injury in STEMI patients.

TRIAL REGISTRATION NUMBER

NCT03004703.

The association between circulating lipoprotein subfractions and lipid content in coronary atheromatous plaques assessed by near-infrared spectroscopy

Background

Lipid content in coronary atheromatous plaques, measured by near-infrared spectroscopy (NIRS), can predict the risk of future coronary events. Biomarkers that reflect lipid content in coronary plaques may therefore improve coronary artery disease (CAD) risk assessment.

Purpose

We aimed to investigate the association between circulating lipoprotein subfractions and lipid content in coronary atheromatous plaques in statin-treated patients with stable CAD undergoing percutaneous coronary intervention.

Methods

56 patients with stable CAD underwent three-vessel imaging with NIRS when feasible. The coronary artery segment with the highest lipid content, defined as the maximum lipid core burden index within any 4 mm length across the entire lesion (maxLCBI_4mm), was defined as target segment. Lipoprotein subfractions and Lipoprotein a (Lp(a)) were analyzed in fasting serum samples by nuclear magnetic resonance spectroscopy and by standard in-hospital procedures, respectively. Penalized linear regression analyses were used to identify the best predictors of maxLCBI_4mm. The uncertainty of the lasso estimates was assessed as the percentage presence of a variable in resampled datasets by bootstrapping.

Results

Only modest evidence was found for an association between lipoprotein subfractions and maxLCBI_4mm. The lipoprotein subfractions with strongest potential as predictors according to the percentage presence in resampled datasets were Lp(a) (78.1 % presence) and free cholesterol in the smallest high-density lipoprotein (HDL) subfractions (74.3 % presence). When including established cardiovascular disease (CVD) risk factors in the regression model, none of the lipoprotein subfractions were considered potential predictors of maxLCBI_4mm.

Conclusion

In this study, serum levels of Lp(a) and free cholesterol in the smallest HDL subfractions showed the strongest potential as predictors for lipid content in coronary atheromatous plaques. Although the evidence is modest, our study suggests that measurement of lipoprotein subfractions may provide additional information with respect to coronary plaque composition compared to traditional lipid measurements, but not in addition to established risk factors. Further and larger studies are needed to assess the potential of circulating lipoprotein subfractions as meaningful biomarkers both for lipid content in coronary atheromatous plaques and as CVD risk markers.

Associations between circulating microRNAs and lipid-rich coronary plaques measured with near-infrared spectroscopy

Lipid-rich coronary atherosclerotic plaques often cause myocardial infarction (MI), and circulating biomarkers that reflect lipid content may predict risk of MI. We investigated the association between circulating microRNAs (miRs) are lipid-rich coronary plaques in 47 statin-treated patients (44 males) with stable coronary artery disease undergoing percutaneous coronary intervention. We assessed lipid content in non-culprit coronary artery lesions with near-infrared spectroscopy and selected the 4 mm segment with the highest measured lipid core burden index (maxLCBI_4mm). Lipid-rich plaques were predefined as a lesion with maxLCBI_4mm ≥ 324.7. We analyzed 177 circulating miRs with quantitative polymerase chain reaction in plasma samples. The associations between miRs and lipid-rich plaques were analyzed with elastic net. miR-133b was the miR most strongly associated with lipid-rich coronary plaques, with an estimated 18% increase in odds of lipid-rich plaques per unit increase in miR-133b. Assessing the uncertainty by bootstrapping, miR-133b was present in 82.6% of the resampled dataset. Inclusion of established cardiovascular risk factors did not attenuate the association. No evidence was found for an association between the other analyzed miRs and lipid-rich coronary plaques. Even though the evidence for an association was modest, miR-133b could be a potential biomarker of vulnerable coronary plaques and risk of future MI. However, the prognostic value and clinical relevance of miR-133b needs to be assessed in larger cohorts.

Coronary Artery Lesion Lipid Content and Plaque Burden in Diabetic and Nondiabetic Patients: PROSPECT II

BACKGROUND

Patients with diabetes have increased rates of major adverse cardiac events (MACEs). We hypothesized that this is explained by diabetes-associated differences in coronary plaque morphology and lipid content.

METHODS

In PROSPECT II (Providing Regional Observations to Study Predictors of Events in the Coronary Tree), 898 patients with acute myocardial infarction with or without ST-segment elevation underwent 3-vessel quantitative coronary angiography and coregistered near-infrared spectroscopy and intravascular ultrasound imaging after successful percutaneous coronary intervention. Subsequent MACEs were adjudicated to either treated culprit lesions or untreated nonculprit lesions. This substudy stratified patients by diabetes status and assessed baseline culprit and nonculprit prevalence of high-risk plaque characteristics defined as maximum plaque burden ≥70% and maximum lipid core burden index ≥324.7. Separate covariate-adjusted multivariable models were performed to identify whether diabetes was associated with nonculprit lesion-related MACEs and high-risk plaque characteristics.

RESULTS

Diabetes was present in 109 of 898 patients (12.1%). During a median 3.7-year follow-up, MACEs occurred more frequently in patients with versus without diabetes (20.1% versus 13.5% [odds ratio (OR), 1.94 (95% CI, 1.14-3.30)]), primarily attributable to increased risk of myocardial infarction related to culprit lesion restenosis (4.3% versus 1.1% [OR, 3.78 (95% CI, 1.12-12.77)]) and nonculprit lesion-related spontaneous myocardial infarction (9.3% versus 3.8% [OR, 2.74 (95% CI, 1.25-6.04)]). However, baseline prevalence of high-risk plaque characteristics was similar for patients with versus without diabetes concerning culprit (maximum plaque burden ≥70%: 90% versus 93%, P=0.34; maximum lipid core burden index ≥324.7: 66% versus 70%, P=0.49) and nonculprit lesions (maximum plaque burden ≥70%: 23% versus 22%, P=0.37; maximum lipid core burden index ≥324.7: 26% versus 24%, P=0.47). In multivariable models, diabetes was associated with MACEs in nonculprit lesions (adjusted OR, 2.47 [95% CI, 1.21-5.04]) but not with prevalence of high-risk plaque characteristics (adjusted OR, 1.21 [95% CI, 0.86-1.69]).

CONCLUSIONS

Among patients with recent myocardial infarction, both treated and untreated lesions contributed to the diabetes-associated ≈2-fold increased MACE rate during the 3.7-year follow-up. Diabetes-related plaque characteristics that might underlie this increased risk were not identified by multimodality imaging.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02171065.

Small LDL subfractions are associated with coronary atherosclerosis despite no differences in conventional lipids

Lipoprotein subfractions currently represent a new source of cardiovascular disease (CVD) risk markers that may provide more information than conventional lipid measures. We aimed to investigate whether lipoprotein subfractions are associated with coronary atherosclerosis in patients without prior known CVD. Fasting serum samples from 60 patients with suspected coronary artery disease (CAD) were collected before coronary angiography and analyzed by nuclear magnetic resonance (NMR) spectroscopy. The severity of coronary atherosclerosis was quantified by the Gensini score (≤20.5 = nonsignificant coronary atherosclerosis, 20.6-30.0 = intermediate coronary atherosclerosis, ≥30.1 = significant CAD). Differences in lipoprotein subfractions between the three Gensini groups were assessed by two-way ANOVA, adjusted for statin use. Despite no differences in conventional lipid measures between the three Gensini groups, patients with significant CAD had higher apolipoprotein-B/apolipoprotein-A1 ratio, 30% more small and dense low-density lipoprotein 5 (LDL-5) particles, and increased levels of cholesterol, triglycerides, and phospholipids within LDL-5 compared with patients with nonsignificant coronary atherosclerosis and intermediate coronary atherosclerosis (P ≤ 0.001). In addition, the low-density lipoprotein (LDL) cholesterol/high-density lipoprotein cholesterol ratio, and triglyceride levels of LDL 4 were significantly increased in patients with significant CAD compared with patients with nonsignificant coronary atherosclerosis. In conclusion, small and dense lipoprotein subfractions were associated with coronary atherosclerosis in patients without prior CVD. Additional studies are needed to explore whether lipoprotein subfractions may represent biomarkers offering a clinically meaningful improvement in the risk prediction of CAD.

High intensity interval training induces beneficial effects on coronary atheromatous plaques - a randomized trial

BACKGROUND

Coronary atheroma volume is associated with risk of coronary events in coronary artery disease (CAD). Exercise training is a cornerstone in primary and secondary prevention of CAD, but the effect of exercise on coronary atheromatous plaques is largely unknown.

PURPOSE

We assessed the effect of six months supervised high intensity interval training (HIIT) on coronary plaque geometry using intravascular ultrasound in patients with stable CAD following percutaneous coronary intervention (PCI).

METHODS

Sixty patients were randomized to two sessions of weekly supervised HIIT at 85-95% of peak heart rate (n = 30) or to follow contemporary preventive guidelines (control group, n = 30). The study endpoints were change in percent atheroma volume (PAV) and total atheroma volume (TAV) normalized for segment length (TAVnorm) at six-month follow-up.

RESULTS

The change in average PAV for matched coronary segments from baseline to follow-up showed a significant between-group difference (-1.4, 95% CI: -2.7 to -0.1, p = 0.036). There was a significant reduction in the HIIT group (-1.2, 95% CI: -2.1 to -0.2, p = 0.017) while not in the control group (0.2, 95% CI: -0.7 to 1.1, p = 0.616). TAVnorm was reduced (-9 mm3, 95% CI: -14.7 to -3.4, p = 0.002) after HIIT, with a significant between-group difference (-12.0 mm3, 95% CI: -19.9 to -4.2, p = 0.003).

CONCLUSION

In patients with established CAD, a regression of atheroma volume was observed in those undergoing six months of supervised HIIT compared with patients following contemporary preventive guidelines. Our study indicates that high intensity interval training counteracts atherosclerotic coronary disease progression and reduces atheroma volume in residual coronary atheromatous plaques following PCI.

Biomarkers associated with vulnerable plaques

Background

Cardiovascular heart disease is the leading cause of mortality worldwide, with the rupture or thrombosis of an atherosclerotic plaque being the main reason behind an acute coronary syndrome. It has already been established that the morphology of atherosclerotic plaques determine their stability. A lipid rich lesion with a thin fibrous cap is more prone to rupture compared to solid fibrous lesions. In the PROSPECTII study we used Near infrared spectroscopy (NIRS) and Intravascular ultrasound (IVUS) to identify atherosclerotic plaques in the coronary arteries; NIRS-derived lipid core burden index (LCBI) and IVUS-derived plaque burden (PB) identified plaques that caused adverse cardiovascular events.

Purpose

Our aim is to find biomarkers associated with LCBI or PB, to understand the development of vulnerable plaques.

Methods

902 patients were enrolled in this study after successful percutaneous coronary intervention (PCI). A combined NIRS-IVUS catheter was then used to analyze approximately 200m of coronary arteries. Blood samples for biomarker analysis were taken before the PCI procedure and plasma levels of 182 proteins associated with cardiovascular disease were assessed using a novel method for measuring proximity extension assay. Adjusted linear regression models were calculated between the biomarkers and the outcomes of interest, followed by a false discovery rate (FDR) correction.

Results

We found 24 proteins associated with plaque burden and 28 proteins associated with LCBI after using a cut off of two tailed P value &lt;0.05. An overlap of 8 biomarkers could be seen between the two groups. After adjusting the P values with FDR, Angiopoeitin like 3 (ANGPTL3) retained its association to LCBI, and Interleukin 18 receptor 1 (IL18R1) and colony stimulating factor 1 (CSF-1) to plaque burden.

Conclusion

We were able to identify different biomarker patterns associated with plaque burden compared to lipid rich vulnerable plaques. ANGPTL3 was shown to only have an association with lipid rich plaques and not with solid fibrous lesions which further supports its role in vulnerable plaques.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Abbott Vascular, Infraredx, and The Medicines Company

Impact of high intensity interval training on coronary atheromatous plaques evaluated by IVUS – a randomized trial

Background

Coronary atheromatous plaque geometry, expressed as plaque burden (PB) or total atheroma volume (TAV) are both strongly related to the risk of acute and recurrent coronary events and outcomes in coronary artery disease (CAD). Exercise training is a cornerstone in the primary and secondary prevention of atherosclerotic complications, but the knowledge of the effect from exercise on coronary atheromatous plaques is sparse.

Purpose

We assessed the effect of six months supervised high intensity interval training (HIIT) on coronary plaque geometry using intravascular ultrasound in patients with stable CAD following percutaneous coronary intervention (PCI).

Methods

Sixty patients were randomized to two sessions weekly of supervised HIIT at 85–95% of peak heart rate (n=30) or to follow contemporary preventive guidelines (control group, n=30). The primary endpoint was change in PB and TAV normalized for segment length (TAVnorm) at six-month follow-up. All included patients were on stable lipid lowering therapy at least six weeks prior to inclusion with no further adjustments throughout the study.

Results

When comparing matched coronary segments at baseline and follow-up, there was a 1.4 percent points larger reduction in average PB (95% CI: 2.7 to 0.1, p=0.036) in the HIIT group compared to the control group. TAVnorm was reduced by 9 mm3 (95% CI: 14.7 to 3.4, p=0.002) after HIIT, with a between group difference of 12 mm3 (95% CI: 19.9 to 4.2, p=0.003). VO2peak improved more in the HIIT group with a difference in delta VO2 peak between groups of 1.7 mL kg–1 min–1 (95% CI: 0.1 to 3.3, p=0.039). There was also a significant larger reduction in body mass index and waist circumference in the HIIT group compared to the control group (both, p=0.021). In both groups a modest, although significant increase was observed for both HDL-cholesterol and ApoA1, but no significant changes in the LDL, ApoB or HbA1c levels were found.

Conclusions

In patients with established CAD, a regression of PB and TAV was observed in patients undergoing six months of supervised HIIT compared with patients following contemporary preventive guidelines. Our study indicates that exercise increasing VO2 peak counteracts atherosclerotic coronary disease progression and reduces PB and TAV in coronary atheromatous plaques following PCI.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): This study was funded by the Liaison Committee for Central Norway Regional Health Authority, the Norwegian University of Science and Technology (NTNU), and the Research Fund at St. Olavs University Hospital

Interleukin-6 inhibition in ST-elevation myocardial infarction: Immune cell profile in the randomised ASSAIL-MI trial

Background

We recently showed that interleukin (IL)-6 inhibition by tocilizumab improves myocardial salvage in ST-elevation myocardial infarction (STEMI). However, the mechanisms for this effect are not clear.

Methods

In this exploratory sub-study of the ASSAIL-MI trial, we examined leukocyte differential counts and their relation to myocardial salvage and peak troponin T (TnT) in STEMI patients randomised to tocilizumab (n = 101) or placebo (n = 98). We performed RNA-sequencing on whole blood (n = 40) and T cells (n = 20). B and T cell subpopulations were examined by flow cytometry (n = 69).

Findings

(i) STEMI patients had higher neutrophil counts at hospitalisation compared with stable angina patients. (ii) After percutaneous coronary intervention there was a gradual decline in neutrophils, which was significantly more pronounced in the tocilizumab group. (iii) The decrease in neutrophils in the tocilizumab group was associated with improved myocardial salvage and lower peak TnT. (iv) RNA-sequencing suggested that neutrophil function was also attenuated by tocilizumab. (v) B and T cell sub-populations changed only minimally after STEMI with minor effects of tocilizumab, supported as well by RNA-sequencing analyses of T cells. (vi) However, a low CD8⁺ count was associated with improved myocardial salvage in patients admitted to the hospital > 3 h after symptom onset.

Interpretation

Tocilizumab induced a rapid reduction in neutrophils and seemed to attenuate neutrophil function in STEMI patients potentially related to the beneficial effects of tocilizumab on myocardial salvage.

Funding

South-Eastern Norway Regional Health Authority (Nos. 2019067, 2017084), the Central Norway Regional Health Authority and Norwegian Research Council (No. 283867).

CENIT (Impact of Cardiac Exercise Training on Lipid Content in Coronary Atheromatous Plaques Evaluated by Near‐Infrared Spectroscopy): A Randomized Trial

Background

The effect of physical exercise on lipid content of coronary artery plaques is unknown. With near infrared spectroscopy we measured the effect of high intensity interval training (HIIT) on lipid content in coronary plaques in patients with stable coronary artery disease following percutaneous coronary intervention.

Methods and Results

In CENIT (Impact of Cardiac Exercise Training on Lipid Content in Coronary Atheromatous Plaques Evaluated by Near‐Infrared Spectroscopy) 60 patients were randomized to 6 months supervised HIIT or to a control group. The primary end point was change in lipid content measured as maximum lipid core burden index at 4 mm (maxLCBI_4mm). A predefined cutoff of maxLCBI_4mm >100 was required for inclusion in the analysis. Forty‐nine patients (HIIT=20, usual care=29) had maxLCBI_4mm >100 at baseline. Change in maxLCBI_4mm did not differ between groups (−1.2, 95% CI, −65.8 to 63.4, P=0.97). The estimated reduction in maxLCBI_4mm was −47.7 (95% CI, −100.3 to 5.0, P=0.075) and −46.5 (95% CI, −87.5 to −5.4, P=0.027) after HIIT and in controls, respectively. A negative correlation was observed between change in peak oxygen uptake (VO_2peak) and change in lipid content (Spearman’s correlation −0.44, P=0.009). With an increase in VO_2peak above 1 metabolic equivalent task, maxLCBI_4mm was on average reduced by 142 (−8 to −262), whereas the change was −3.2 (154 to −255) with increased VO_2peak below 1 metabolic equivalent task.

Conclusions

Six months of HIIT following percutaneous coronary intervention did not reduce lipid content in coronary plaques compared with usual care. A moderate negative correlation between increase in VO_2peak and change in lipid content generates the hypothesis that exercise with a subsequent increase in fitness may reduce lipid content in coronary atheromatous plaques.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02494947.

Associations between circulating microRNAs and coronary plaque characteristics: potential impact from physical exercise

Background and aims MicroRNAs (miRs) are involved in different steps in the development of atherosclerosis and are proposed as promising biomarkers of coronary artery disease (CAD). We hypothesized that circulating levels of miRs were associated with coronary plaque components assessed by radiofrequency intravascular ultrasound (RF-IVUS) before and after aerobic exercise intervention. Methods 31 patients with CAD treated with percutaneous coronary intervention (PCI) previously included in a randomized trial with aerobic interval training (AIT) or moderate continuous training (MCT) as post-PCI intervention were included. Coronary plaque characteristics by grayscale and RF-IVUS and predefined circulating candidate miRs in plasma were analysed at baseline and follow-up. Associations between miRs and coronary plaque composition, and the potential effect from exercise, were analysed using linear regression. Results Circulating levels of miR-15a-5p, miR-30e-5p, miR-92a-3p, miR-199a-3p, miR-221-3p, and miR-222-3p were associated with baseline coronary necrotic core volume. Following exercise intervention, decreased levels of miR-15a-5p, miR-93-5p, and miR-451a, and increased levels of miR-146a-5p were associated with an observed regression of coronary plaque burden. A mirPath prediction tool identified that genes regulated by miR-15a-5p, miR-199a-3p, and miR-30e-5p were significantly overrepresented in pathways related to fatty acid biosynthesis and fatty acid metabolism. Conclusion This exploratory study demonstrated six miRs associated with coronary necrotic core, a marker of plaque vulnerability. In addition, changes in four miRs were associated with a regression of coronary plaque burden following exercise intervention. These novel findings may identify potential future biomarkers of CAD and coronary plaque composition.

Drug-eluting versus bare metal stents in saphenous vein grafts compared to native coronary vessels. The NORSTENT study

BACKGROUND

Drug-eluting stents (DES) reduce target lesion revascularization (TLR) with no effect on mortality or myocardial infarction (MI) compared to bare metal stents (BMS) in native vessels. Randomized stent studies in saphenous vein grafts (SVG) are few and the reported effects are ambiguous. The NORSTENT study is the first to randomize lesions to percutaneous coronary intervention (PCI) in native vessels and SVG.

AIMS

To compare rate of mortality, MI and TLR across stent and vessel types.

METHODS

In this substudy 6087 patients with a single lesion in native vessels and 164 in SVG, were followed for 5 years.

RESULTS

MI was more frequent in SVG (subdistributional hazard ratio (SHR) 4.95 (3.75 - 6.54, p<0.001), but not affected by stent type. In the first 500 days DES reduced TLR in native vessels (SHR 0.21 ( 0.15 - 0.30)p<0.001) and SVG (SHR 0.18 (0.04 - 0.80) p=0.02). Thereafter DES and BMS were equivalent in native vessels, but DES had a higher TLR rate than BMS in SVG (SHR 3.31 (1.23 - 8.94) p=0.02). After 5 years the TLR rate was still significantly lower for DES in native vessels (3.2 % versus 7.8 %, p<0.001) but not in SVG (21.4 % vs 18. 4%).

CONCLUSION

In SVG no difference in TLR between DES and BMS was observed after 5 years in contrast to persistent benefit in native vessels. The high rate of TLR and myocardial infarction in SVG makes treatment of native vessels a preference whenever feasible and better treatment options for SVG are warranted.  .

Impact of baseline coronary flow and its distribution on fractional flow reserve prediction

Model-based prediction of fractional flow reserve (FFR) in the context of stable coronary artery disease (CAD) diagnosis requires a number of modelling assumptions. One of these assumptions is the definition of a baseline coronary flow, ie, total coronary flow at rest prior to the administration of drugs needed to perform invasive measurements. Here we explore the impact of several methods available in the literature to estimate and distribute baseline coronary flow on FFR predictions obtained with a reduced-order model. We consider 63 patients with suspected stable CAD, for a total of 105 invasive FFR measurements. First, we improve a reduced-order model with respect to previous results and validate its performance versus results obtained with a 3D model. Next, we assess the impact of a wide range of methods to impose and distribute baseline coronary flow on FFR prediction, which proved to have a significant impact on diagnostic performance. However, none of the proposed methods resulted in a significant improvement of prediction error standard deviation. Finally, we show that intrinsic uncertainties related to stenosis geometry and the effect of hyperemic inducing drugs have to be addressed in order to improve FFR prediction accuracy.

Tocilizumab increases citrullinated histone 3 in non-ST segment elevation myocardial infarction

Objective

Beyond reducing inflammation and troponin T (TnT) release, the interleukin-6 receptor antagonist tocilizumab reduces neutrophil counts in patients with non-ST segment elevation myocardial infarction (NSTEMI). It is unclear if this is related to formation of neutrophil extracellular traps (NETs), carrying inflammatory and thrombotic properties.

Methods

In a placebo-controlled trial, 117 patients with NSTEMI were randomised to a single dose of tocilizumab (n=58) or placebo (n=59) before coronary angiography. The NETs related markers double-stranded DNA (dsDNA), myloperoxidase–DNA (MPO–DNA) and citrullinated histone 3 (H3Cit) were measured at five consecutive time points during hospitalisation (days 1–3).

Results

Our major findings were: (1) H3Cit levels were significantly higher in the tocilizumab compared with the placebo group at all time points (all p<0.05), and H3Cit area under the curve (AUC) was 2.3 fold higher in the tocilizumab compared with placebo group (p<0.0001). (2) MPO–DNA and dsDNA did not differ between the groups. (3) In both treatment arms, dsDNA AUC was associated with TnT AUC. (4) Neutrophil count AUC correlated inversely to H3Cit AUC (p=0.015) in the total population.

Conclusions

In patients with NSTEMI, treatment with tocilizumab is associated with increased circulating H3Cit levels, suggesting that tocilizumab enhances NETosis. Further studies should clarify whether NETosis is a relevant side effect of tocilizumab. Regardless of tocilizumab, dsDNA associated with TnT release, indicating a link between extracellular nuclear material and myocardial injury.

Identification of vulnerable plaques and patients by intracoronary near-infrared spectroscopy and ultrasound (PROSPECT II): a prospective natural history study

BACKGROUND

Near-infrared spectroscopy (NIRS) and intravascular ultrasound are promising imaging modalities to identify non-obstructive plaques likely to cause coronary-related events. We aimed to assess whether combined NIRS and intravascular ultrasound can identify high-risk plaques and patients that are at risk for future major adverse cardiac events (MACEs).

METHODS

PROSPECT II is an investigator-sponsored, multicentre, prospective natural history study done at 14 university hospitals and two community hospitals in Denmark, Norway, and Sweden. We recruited patients of any age with recent (within past 4 weeks) myocardial infarction. After treatment of all flow-limiting coronary lesions, three-vessel imaging was done with a combined NIRS and intravascular ultrasound catheter. Untreated lesions (also known as non-culprit lesions) were identified by intravascular ultrasound and their lipid content was assessed by NIRS. The primary outcome was the covariate-adjusted rate of MACEs (the composite of cardiac death, myocardial infarction, unstable angina, or progressive angina) arising from untreated non-culprit lesions during follow-up. The relations between plaques with high lipid content, large plaque burden, and small lumen areas and patient-level and lesion-level events were determined. This trial is registered with ClinicalTrials.gov, NCT02171065.

FINDINGS

Between June 10, 2014, and Dec 20, 2017, 3629 non-culprit lesions were characterised in 898 patients (153 [17%] women, 745 [83%] men; median age 63 [IQR 55-70] years). Median follow-up was 3·7 (IQR 3·0-4·4) years. Adverse events within 4 years occurred in 112 (13·2%, 95% CI 11·0-15·6) of 898 patients, with 66 (8·0%, 95% CI 6·2-10·0) arising from 78 untreated non-culprit lesions (mean baseline angiographic diameter stenosis 46·9% [SD 15·9]). Highly lipidic lesions (851 [24%] of 3500 lesions, present in 520 [59%] of 884 patients) were an independent predictor of patient-level non-culprit lesion-related MACEs (adjusted odds ratio 2·27, 95% CI 1·25-4·13) and non-culprit lesion-specific MACEs (7·83, 4·12-14·89). Large plaque burden (787 [22%] of 3629 lesions, present in 530 [59%] of 898 patients) was also an independent predictor of non-culprit lesion-related MACEs. Lesions with both large plaque burden by intravascular ultrasound and large lipid-rich cores by NIRS had a 4-year non-culprit lesion-related MACE rate of 7·0% (95% CI 4·0-10·0). Patients in whom one or more such lesions were identified had a 4-year non-culprit lesion-related MACE rate of 13·2% (95% CI 9·4-17·6).

INTERPRETATION

Combined NIRS and intravascular ultrasound detects angiographically non-obstructive lesions with a high lipid content and large plaque burden that are at increased risk for future adverse cardiac outcomes.

FUNDING

Abbott Vascular, Infraredx, and The Medicines Company.

Analyses of Increased Mortality in New and Known Diabetes in Patients with Coronary Disease Enrolled in the NORSTENT Randomized Study

BACKGROUND

NORSTENT trial randomized 9,013 patients to percutaneous coronary intervention with drug-eluting stents (DES) or bare-metal stents (BMS) with a 5-year follow-up. Among the patients, 5,512 had measured either fasting glucose level or percent glycated hemoglobin (HbA1c) at the index procedure. That cohort constitutes the present study population analyzing mortality and evaluating treatment heterogeneity of randomized stent in diabetic versus nondiabetic subgroups.

RESULTS

The cohort consisted of 4,174 (75.7%) patients without diabetes, 716 (13.0%) with known diabetes, and 622 (11.3%) with no diabetes in history but elevated fasting glucose level >7.0 mmol/L or HbA1c >6.5% and therefore defined as new diabetes. Patients with known diabetes had a significantly increased all-cause (hazard ratio [HR] 1.99, 95% CI 1.51-2.62, p < 0.001), cardiac (subhazard ratio [SHR] 2.47, 95% CI 1.55-3.93, p < 0.001), and noncardiac (SHR 1.74, 95% CI 1.23-2.44, p = 0.002) mortality after adjustment for baseline variables. In the follow-up of 5 years, patients with new diabetes, however, had a marginally increased all-cause (HR 1.40, 95% CI 1.01-1.93, p = 0.043) and significantly increased noncardiac mortality (SHR 1.52, 95% CI 1.06-2.20, p = 0.025), but no increase in cardiac mortality (SHR 1.06, 95% CI 0.53-2.12, p = 0.86) after the same adjustment. The majority of the mortality was cardiac in the first 1-2 years after intervention; thereafter, noncardiac mortality dominated. However, the time period for when noncardiac mortality became the dominating cause varied considerably and significantly between the groups. There was no heterogeneity in mortality in response to randomized stent between diabetics and nondiabetics.

CONCLUSION

Known diabetes has increased cardiac and noncardiac mortality in contrast to new diabetes which is only associated with increased noncardiac mortality during the 5-year follow-up. Diabetic and nondiabetic patients have the same response to the treatment with BMS or DES.

Lipoprotein subfraction LDL-5 and the presence of coronary atherosclerosis

Background

Coronary artery disease (CAD) has high mortality rates and is a frequent cause of death globally. Serum lipids play a pivotal role in the development of atherosclerosis, and elevated levels of total cholesterol, low density lipoprotein (LDL) cholesterol, and triglycerides are well known risk factors of cardiovascular disease (CVD). However, there are limitations in the ability to predict CVD risk, which has led to an increased clinical interest in identifying novel risk markers. With the advances in lipidomic technology, lipoprotein subfractions may provide additional information that is missing in today's evaluation of CVD risk. Lipoprotein subfractions differ in size and density, and recent studies suggest that high density of small LDL particles provide a greater risk for CVD.

Purpose

To investigate whether lipoprotein subfractions are associated with the presence and extent of coronary atherosclerosis.

Methods

Fasting serum samples from 60 participants with suspected stable CAD were collected before scheduled coronary angiography, and analysed by nuclear magnetic resonance (NMR). The presence and extent of atherosclerosis were quantified by the Gensini Score. Participants were classified into one of three Gensini groups based on severity (&lt;20.5, normal; 20.6–30, non-significant CAD; &gt;30.1, significant CAD).

Results

A three-way ANOVA, adjusted for statin-use and sex, revealed statistically significant differences (p&lt;0.005) in LDL-5 particle number, LDL-5 triglycerides, and LDL-5 phospholipids between the Gensini groups. In addition, significant differences (p&lt;0.005) were found in the ratios apolipoprotein A/apolipoprotein B and LDL cholesterol/HDL cholesterol between the Gensini groups. All significant variables, identified by the three-way ANOVA, displayed the highest levels in the Gensini group with significant CAD.

Conclusion

Despite no difference in the traditional clinical measurements (total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides), NMR-lipidomics revealed significant differences in LDL-5 between the Gensini groups. Interestingly, our results reveal that those with significant CAD have a higher density of small LDL subfractions.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Norwegian Health Association, The Liaison Committee for Education, Research and Innovation in Central Norway

Percutaneous Coronary Intervention for Vulnerable Coronary Atherosclerotic Plaque

BACKGROUND

Acute coronary syndromes most commonly arise from thrombosis of lipid-rich coronary atheromas that have large plaque burden despite angiographically appearing mild.

OBJECTIVES

This study sought to examine the outcomes of percutaneous coronary intervention (PCI) of non-flow-limiting vulnerable plaques.

METHODS

Three-vessel imaging was performed with a combination intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) catheter after successful PCI of all flow-limiting coronary lesions in 898 patients presenting with myocardial infarction (MI). Patients with an angiographically nonobstructive stenosis not intended for PCI but with IVUS plaque burden of ≥65% were randomized to treatment of the lesion with a bioresorbable vascular scaffold (BVS) plus guideline-directed medical therapy (GDMT) versus GDMT alone. The primary powered effectiveness endpoint was the IVUS-derived minimum lumen area (MLA) at protocol-driven 25-month follow-up. The primary (nonpowered) safety endpoint was randomized target lesion failure (cardiac death, target vessel-related MI, or clinically driven target lesion revascularization) at 24 months. The secondary (nonpowered) clinical effectiveness endpoint was randomized lesion-related major adverse cardiac events (cardiac death, MI, unstable angina, or progressive angina) at latest follow-up.

RESULTS

A total of 182 patients were randomized (93 BVS, 89 GDMT alone) at 15 centers. The median angiographic diameter stenosis of the randomized lesions was 41.6%; by near-infrared spectroscopy-IVUS, the median plaque burden was 73.7%, the median MLA was 2.9 mm², and the median maximum lipid plaque content was 33.4%. Angiographic follow-up at 25 months was completed in 167 patients (91.8%), and the median clinical follow-up was 4.1 years. The follow-up MLA in BVS-treated lesions was 6.9 ± 2.6 mm² compared with 3.0 ± 1.0 mm² in GDMT alone-treated lesions (least square means difference: 3.9 mm²; 95% confidence interval: 3.3 to 4.5; p < 0.0001). Target lesion failure at 24 months occurred in similar rates of BVS-treated and GDMT alone-treated patients (4.3% vs. 4.5%; p = 0.96). Randomized lesion-related major adverse cardiac events occurred in 4.3% of BVS-treated patients versus 10.7% of GDMT alone-treated patients (odds ratio: 0.38; 95% confidence interval: 0.11 to 1.28; p = 0.12).

CONCLUSIONS

PCI of angiographically mild lesions with large plaque burden was safe, substantially enlarged the follow-up MLA, and was associated with favorable long-term clinical outcomes, warranting the performance of an adequately powered randomized trial. (PROSPECT ABSORB [Providing Regional Observations to Study Predictors of Events in the Coronary Tree II Combined with a Randomized, Controlled, Intervention Trial]; NCT02171065).

Establishing the 99th percentile of a novel assay for high-sensitivity troponin I in a healthy blood donor population

Background

The recommended cut-off of cardiac troponin (cTn) for the diagnosis of acute myocardial infarction (AMI) is the 99th percentile in a healthy reference population. We aimed to determine the 99th percentile of the novel ADVIA Centaur® High Sensitivity Troponin I assay (Siemens Healthcare Diagnostics) in fresh lithium heparin plasma samples from healthy blood donors.

Methods

A total of 1000 apparently healthy blood donors were included. High-sensitivity (hs) cTnI, hs-cTnT, creatinine and N-terminal pro b-type natriuretic peptide (NT-proBNP) were measured in fresh lithium heparin plasma samples, and glycated hemoglobin (HbA1c) was measured in ethylenediaminetetraacetic acid (EDTA)-blood. The 99th percentile was estimated for the whole population, as well as for males and females separately.

Results

For the total population the 99th percentile of ADVIA Centaur® High Sensitivity Troponin I was 96 (65-149) ng/L. The estimated value differed significantly from results published by others and was highly dependent on which values were considered statistical outliers.

Conclusions

The estimated 99th percentile for hs-cTnI in the population studied differed significantly from previously published results. There is a need for further specifications regarding how subjects used for estimating the 99th percentile of cTns in healthy populations should be recruited and how outlier values should be identified, as this can highly influence the diagnostic cut-off applied for AMI.

Acute perimyocarditis with cardiac tamponade in COVID-19 infection without respiratory disease

The COVID-19 pandemic with its severe respiratory disease has caused overflow to hospitals and intensive care units. Elevated troponins and natriuretic peptides are related to cardiac injury and poor prognosis. We present a young woman with COVID-19 infection with haemodynamic instability caused by acute perimyocarditis and cardiac tamponade. Troponin T was modestly elevated. Focused cardiac ultrasound made the diagnosis. Echocardiography revealed transient thickening of the myocardial walls. After pericardial drainage and supportive care, she improved significantly within 1 week without targeted therapy. The case illustrates the importance of cardiac diagnostic imaging in patients with COVID-19 and elevated cardiac biomarkers.

Novel Insights Into the Effects of Interleukin 6 Antagonism in Non-ST-Segment-Elevation Myocardial Infarction Employing the SOMAscan Proteomics Platform

Background Interleukin 6 concentration is associated with myocardial injury, heart failure, and mortality after myocardial infarction. In the Norwegian tocilizumab non-ST-segment-elevation myocardial infarction trial, the first randomized trial of interleukin 6 blockade in myocardial infarction, concentration of both C-reactive protein and troponin T were reduced in the active treatment arm. In this follow-up study, an aptamer-based proteomic approach was employed to discover additional plasma proteins modulated by tocilizumab treatment to gain novel insights into the effects of this therapeutic approach. Methods and Results Plasma from percutaneous coronary intervention-treated patients, 24 in the active intervention and 24 in the placebo-control arm, drawn 48 hours postrandomization were randomly selected for analysis with the SOMAscan assay. Employing slow off-rate aptamers, the relative abundance of 1074 circulating proteins was measured. Proteins identified as being significantly different between groups were subsequently measured by enzyme immunoassay in the whole trial cohort (117 patients) at all time points (days 1-3 [7 time points] and 3 and 6 months). Five proteins identified by the SOMAscan assay, and subsequently confirmed by enzyme immunoassay, were significantly altered by tocilizumab administration. The acute-phase proteins lipopolysaccharide-binding protein, hepcidin, and insulin-like growth factor-binding protein 4 were all reduced during the hospitalization phase, as was the monocyte chemoattractant C-C motif chemokine ligand 23. Proteinase 3, released primarily from neutrophils, was significantly elevated. Conclusions Employing the SOMAscan aptamer-based proteomics platform, 5 proteins were newly identified that are modulated by interleukin 6 antagonism and may mediate the therapeutic effects of tocilizumab in non-ST-segment-elevation myocardial infarction.

Polymer-free drug-coated vs. bare-metal coronary stents in patients undergoing non-cardiac surgery: a subgroup analysis of the LEADERS FREE trial

AIMS

To compare the outcomes of patients undergoing non-cardiac surgery (NCS) after PCI with either a drug-coated stent (DCS) or a bare-metal stent (BMS), followed by 1-month dual antiplatelet therapy and to explore the impact of the timing of NCS.

METHODS

This is a subgroup analysis of the LEADERS FREE trial. The primary safety end point was a composite of cardiac death, myocardial infarction, or stent thrombosis, and the primary efficacy end point was clinically driven target lesion revascularization (TLR).

RESULTS

Out of 2432 patients included in the LEADERS FREE trial, 278 (11.4%) underwent NCS within 1 year after PCI. Among NCS patients, the 1-year safety end point was numerically lower with DCS; however, this difference was not significant as compared to BMS (4.7% vs. 10.1%, HR: 0.459 [0.178-1.183], p = 0.099), clinically driven TLR was significantly lower after DCS (2.4% vs. 8.3%, HR: 0.281 [0.079-0.996], p = 0.036), and BARC 3-5 bleeding was similar with DCS vs. BMS (10.2% vs. 7.5%, p = 0.438). In patients treated with BMS, NCS within 3 months after PCI was associated with higher incidence of the safety end point than NCSs performed later: 14.9% vs. 4.4%, HR: 3.586 [1.012-12.709], p = 0.034. The timing of surgery had no impact on patients treated with DCS (4.7% vs. 4.7%, p = 0.947).

CONCLUSIONS

Among patients undergoing NCS after PCI, DCS-treated patients had a lower probability of clinically driven TLR compared with BMS. However, there was no significant difference in the occurrence of the primary composite safety end point or bleeding complications. Early NCS after BMS-PCI was associated with impaired safety, while the timing of NCS had no such influence after DCS implantation.

The Effect of Drug-Eluting Stents on Target Lesion Revascularization in Native Coronary Arteries: Results from the NORSTENT Randomized Study

BACKGROUND

The NORSTENT trial randomized 9,013 patients to percutaneous coronary intervention (PCI) with a drug-eluting stent (DES) or bare-metal stent (BMS) with 5-year follow-up. No difference was found in the composite primary outcome of death from any cause and nonfatal spontaneous myocardial infarction after a median of 5 years of follow-up. Secondary outcomes included repeat revascularizations, which were reduced by DES. We report the occurrence of target lesion revascularization (TLR) in time and across demographic and clinical subgroups in patients with lesions in native coronary arteries (n = 8,782).

RESULTS

Clinically driven TLR was performed on 488 (5.6%) of the 8,782 patients during 5 years of follow-up. Male gender, older age, visible thrombus in the lesion, and larger stent diameter were associated with less TLR; multivessel disease and longer stents were associated with a higher risk of TLR. There was a substantial and highly significant reduction of the risk of any TLR after 5 years in the DES group (hazard ratio [HR] 0.44, 95% confidence interval [CI] 0.36-0.52], p < 0.001). The effect of DES on TLR was limited in time to the first 2 years in the study with no evidence of a later rebound effect. The reduction in TLR after DES insertion was consistent across subgroups defined by gender, age, diabetes status, renal function, and lesion and stent characteristics. The number needed to treat with DES (vs. BMS) to prevent 1 TLR ranged from 4 to 110 across clinically relevant subgroups.

CONCLUSION

DES have a time-limited effect on the rate of TLR, but with a substantial and highly significant reduction in the first 2 years after the procedure. This effect was found to be consistent across all important clinical subgroups.

Treatment of ST-elevation myocardial infarction - an observational study

BACKGROUND

ST-elevation myocardial infarction is treated with reperfusion, either in the form of primary percutaneous coronary intervention (PCI) or thrombolytic therapy. The choice of treatment depends on transport time to the nearest PCI centre. Norway's geography means that thrombolytic therapy will be appropriate for many patients. Irrespective of treatment choice, it is important to avoid delays. We wished to compare the outcomes of primary PCI and thrombolytic therapy in our healthcare region and to examine whether reperfusion therapy was administered within the recommended time window.

MATERIAL AND METHOD

Using registry data and patient medical records, we compared the outcomes of primary PCI and thrombolytic therapy in cases of ST-elevation myocardial infarction in the Central Norway Regional Health Authority in the period 2015-16. The outcomes analysed were 30-day mortality, ejection fraction measured by echocardiography during the hospital stay, incidence of bleeding complications, and time from diagnosis to start of treatment.

RESULTS

The study population comprised 648 patients with ST-elevation myocardial infarction. Of these, 382 were treated with primary PCI and 266 received thrombolytic therapy. The 30-day mortality was 5.5 % in the primary PCI group and 5.6 % in the thrombolysis group (p = 1.0). There were no significant differences in ejection fraction and no cases of serious bleeding. In 45 % of the total population, reperfusion therapy was started later than recommended in guidelines.

INTERPRETATION

There was no statistically significant difference in mortality or ejection fraction when comparing primary PCI and thrombolytic therapy in an unselected population with ST-elevation myocardial infarction. Many patients experienced delayed start of treatment . It is important to take action to reduce delays at all stages of the therapeutic chain. Thrombolytic therapy should be considered when it is unclear whether transport time to a PCI centre will exceed that recommended in guidelines.

Rationale for the ASSAIL-MI-trial: a randomised controlled trial designed to assess the effect of tocilizumab on myocardial salvage in patients with acute ST-elevation myocardial infarction (STEMI)

Introduction

Interleukin-6 (IL-6) may be involved in ischaemia-reperfusion injury and myocardial remodelling after myocardial infarction (MI). We have recently shown that IL-6 inhibition by tocilizumab attenuates systemic inflammation and troponin T-release in patients with acute non-ST elevation MI (NSTEMI). Experimental studies suggest that IL-6 inhibition can limit infarct size through anti-inflammatory mechanisms, but this has not been tested in clinical studies. With the ASSessing the effect of Anti-IL-6 treatment in MI (ASSAIL-MI) trial, we aim to examine whether a single administration of the IL-6 receptor antagonist tocilizumab can increase myocardial salvage in patients with acute ST-elevation MI (STEMI).

Methods and analysis

The ASSAIL-MI trial is a randomised, double blind, placebo-controlled trial, conducted at three high-volume percutaneous coronary intervention (PCI) centres in Norway. 200 patients with first-time STEMI presenting within 6 hours of the onset of chest pain will be randomised to receive tocilizumab or matching placebo prior to PCI. The patients are followed-up for 6 months. The primary endpoint is the myocardial salvage index measured by cardiac MRI (CMR) 3–7 days after the intervention. Secondary endpoints include final infarct size measured by CMR and plasma markers of myocardial necrosis. Efficacy and safety assessments during follow-up include blood sampling, echocardiography and CMR.

Ethics and dissemination

Based on previous experience the study is considered feasible and safe. If tocilizumab increases myocardial salvage, further endpoint-driven multicentre trials may be initiated. The ASSAIL-MI trial has the potential to change clinical practice in patients with STEMI.

Registration

Clinicaltrials.gov, identifier NCT03004703.

P1547Circulating lipoprotein subfractions as new non-invasive biomarkers of coronary atherosclerosis

Objectives

Coronary artery disease (CAD) is the most common cause of death globally. In the next decade, the number of people at risk is expected to increase, due to obesity, inactivity and diabetes. Therefore, precise risk-prediction models will be increasingly important for the healthcare system, to be able to initiate cost-efficient prevention strategies. One of the first steps in CAD-development is sub-clinical atherosclerosis. Biomarkers that could reflect the presence of coronary atherosclerosis would be extremely valuable for risk prediction of myocardial infarction (MI). Serum cholesterol levels are key variables in risk prediction; however, there is growing interest for exploring the potential of other lipid subclasses. The aim of this study is to identify specific lipoprotein subfractions that are associated with the extent of coronary atherosclerosis.

Methods

60 patients with suspected CAD were enrolled. Blood samples were collected before the partiens underwent coronary angiography. The extent of coronary atherosclerosis were quantified using the Gensini score. The partients were classified into three groups based on their Gensini score (<20.5: normal, 20.6–30: non-significant CAD and >30.1: significant CAD). The blood samples were analyzed by nucelar magnetic resonance (NMR) lipidomics. Univariate and multivariate statistical tests were used to determine whether lipoprotein subfractions were associated with the extent of coronary atherosclerosis.

Results and discussion

Of the 117 lipoprotein subfractions quantified, 10 were different in patients with significant CAD compared to patients with normal vessels in non-statin users (p=0.005). Despite no difference in total cholesterol, LDL and HDL cholesterol between the three Gensini groups, NMR lipidomics revealed that patients with significant CAD had twice as many circulating LDL-5 and LDL-6 particles as patients with normal vessels. Furthermore, three types of small LDL-subfractions, called LDL-5-TG, LDL-5-ApoB and LDL-6-ApoB, were significantly increased in patients with significant CAD. Interestingly, previous studies have suggested that small LDL particles are more atherogenic than larger particles. In addition, patients with significant CAD had low levels of ApoA1 containing HDL particles, and high levels of two different small VLDL particles. Previous studies have indicated that small VLDLs are more atherogenic than larger VLDLs, and does to a greater extent penetrate the vessel intima.

Conclusions

This study reveals strong associations between serum lipoprotein subfractions and the degree of coronary atherosclerosis quantified by Gensini score. Especially, the high levels of certain types of small LDL-particles in patients with CAD, indicates that measuring lipoprotein subfractions may provide added value to risk prediction models for MI. However, these findings needs to be further explored and validated in large cohort studies.

Acknowledgement/Funding

Norwegian Health Association, the Liaison Committee between the Central Norway Regional Health Authority (RHA) and NTNU

Perioperative Factors Associated With Changes in Troponin T During Coronary Artery Bypass Grafting

OBJECTIVE

Investigate important clinical and operative variables associated with increases in cardiac troponin T (cTnT) as indicators of myocardial injury after coronary artery bypass grafting (CABG).

DESIGN

Prospective cohort study.

SETTING

Single university hospital.

PARTICIPANTS

The study comprised 626 patients undergoing isolated CABG from April 2008 through April 2010 with a validation cohort (n = 686) from 2015-2017.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Perioperative variables were registered prospectively. The extent of diffuse coronary atherosclerosis and significant stenoses were assessed with preoperative coronary angiography. Mixed model analysis was used to construct a statistical model explaining the course of cTnT concentrations. The model was adjusted for preoperative and intraoperative/postoperative myocardial infarction (MI) for independent assessment of additional variables. Clinical factors associated with increased cTnT concentrations during and after CABG were longer duration of cardiopulmonary bypass (p < 0.001), higher preoperative creatinine (p < 0.001), New York Heart Association functional classification IV (p = 0.006), reduced LVEF (p = 0.034), higher preoperative C-reactive protein (p = 0.049), and intraoperative/postoperative MI (p < 0.001). Factors associated with decreasing cTnT concentrations during CABG were higher BSA (p < 0.001) and a recent preoperative MI (p < 0.001). The extent of diffuse coronary atherosclerosis and significant stenoses were not associated with changes in cTnT (p = 0.35). Results were similar in the validation cohort.

CONCLUSIONS

Left ventricular ejection fraction, New York Heart Association classification, kidney function, inflammation status, duration of cardiopulmonary bypass, body surface area, and preoperative MI were associated with the cTnT rise-and-fall pattern related to myocardial injury after CABG. Information regarding these variables may be valuable when using cTnT in the diagnostic workup of postoperative MI.

BEtablocker Treatment After acute Myocardial Infarction in revascularized patients without reduced left ventricular ejection fraction (BETAMI): Rationale and design of a prospective, randomized, open, blinded end point study

BACKGROUND

Current guidelines on the use of β-blockers in post-acute myocardial infarction (MI) patients without reduced left ventricular ejection fraction (LVEF) are based on studies before the implementation of modern reperfusion and secondary prevention therapies. It remains unknown whether β-blockers will reduce mortality and recurrent MI in contemporary revascularized post-MI patients without reduced LVEF.

DESIGN

BETAMI is a prospective, randomized, open, blinded end point multicenter study in 10,000 MI patients designed to test the superiority of oral β-blocker therapy compared to no β-blocker therapy. Patients with LVEF ≥40% following treatment with percutaneous coronary intervention or thrombolysis and/or no clinical signs of heart failure are eligible to participate. The primary end point is a composite of all-cause mortality or recurrent MI obtained from national registries over a mean follow-up period of 3 years. Safety end points include rates of nonfatal MI, all-cause mortality, ventricular arrhythmias, and hospitalizations for heart failure obtained from hospital medical records 30 days after randomization, and from national registries after 6 and 18 months. Key secondary end points include recurrent MI, heart failure, cardiovascular and all-cause mortality, and clinical outcomes linked to β-blocker therapy including drug adherence, adverse effects, cardiovascular risk factors, psychosocial factors, and health economy. Statistical analyses will be conducted according to the intention-to-treat principle. A prespecified per-protocol analysis (patients truly on β-blockers or not) will also be conducted.

CONCLUSIONS

The results from the BETAMI trial may have the potential of changing current clinical practice for treatment with β-blockers following MI in patients without reduced LVEF. EudraCT number 2018-000590-75.

Reproducibility of optical coherence tomography in vein grafts used for coronary revascularization

BACKGROUND

Optical coherence tomography (OCT) is a high-resolution imaging modality able to provide near-histological images of vessel walls making it possible to distinguish intima and media layers of the vessel wall separately. The use of this imaging technique is increasing while data on the variability and reliability is lacking. The aim of this study was to investigate the reproducibility of frequency-domain OCT in vein grafts used for coronary revascularization.

METHODS

Five pullbacks were analyzed by the same analyst with a 1-month delay (intraobserver) and by two different analysts (interobserver). Five pairs of pullbacks from the same catheters and vein graft were also analyzed (inter pullback).

RESULTS

Optical coherence tomography showed low variability in intra- and interobserver analysis with relative differences of mean media and intima thicknesses and areas of less than 5% for most parameters. Relative differences of the same parameters in the inter pullback analysis were in the 5-15% range. Intra- and interobserver reliability was excellent (intraclass correlation coefficient [ICC] > 0.90) for intima thickness and intima, media and intima-media area measurements. Inter pullback reliability was good (ICC: 0.75-0.90) for intima and intima-media area measurements, and moderate to good for mean intima thickness measurements (ICC: 0.79; 0.7338-0.8284).

CONCLUSIONS

Optical coherence tomography provides good reproducibility for the measurements of parameters relevant for the development of atherosclerosis in vein grafts.

CLINICAL TRIAL REGISTRATION

ID NCT01834846.

Uncertainty Quantification and Sensitivity Analysis for Computational FFR Estimation in Stable Coronary Artery Disease

PURPOSE

The main objectives of this study are to validate a reduced-order model for the estimation of the fractional flow reserve (FFR) index based on blood flow simulations that incorporate clinical imaging and patient-specific characteristics, and to assess the uncertainty of FFR predictions with respect to input data on a per patient basis.

METHODS

We consider 13 patients with symptoms of stable coronary artery disease for which 24 invasive FFR measurements are available. We perform an extensive sensitivity analysis on the parameters related to the construction of a reduced-order (hybrid 1D-0D) model for FFR predictions. Next we define an optimal setting by comparing reduced-order model predictions with solutions based on the 3D incompressible Navier-Stokes equations. Finally, we characterize prediction uncertainty with respect to input data and identify the most influential inputs by means of sensitivity analysis.

RESULTS

Agreement between FFR computed by the reduced-order model and by the full 3D model was satisfactory, with a bias ([Formula: see text]) of [Formula: see text] at the 24 measured locations. Moreover, the uncertainty related to the factor by which peripheral resistance is reduced from baseline to hyperemic conditions proved to be the most influential parameter for FFR predictions, whereas uncertainty in stenosis geometry had greater effect in cases with low FFR.

CONCLUSION

Model errors related to solving a simplified reduced-order model rather than a full 3D problem were small compared with uncertainty related to input data. Improved measurement of coronary blood flow has the potential to reduce uncertainty in computational FFR predictions significantly.

Completeness and correctness of acute myocardial infarction diagnoses in a medical quality register and an administrative health register

Aims: Health registers are used for administrative purposes, disease surveillance, quality assessment, and research. The value of the registers is entirely dependent on the quality of their data. The aim of this study was to investigate and compare the completeness and correctness of the acute myocardial infarction (AMI) diagnosis in the Norwegian Myocardial Infarction Register and in the Norwegian Patient Register. Methods: All Norwegian patients admitted directly to St Olavs hospital, Trondheim University Hospital, Trondheim University Hospital from 1 July to 31 December 2012 and who had plasma levels of cardiac troponin T measured during their hospitalization ( n=4835 unique individuals, n=5882 hospitalizations) were identified in the hospital biochemical database. A gold standard for AMI was established by evaluation of maximum troponin T levels and by review of the information in the medical records. Cases of AMI in the registers were classified as true positive, false positive, true negative, and false negative according to the gold standard. We calculated sensitivity, positive predictive value (PPV), specificity, and negative predictive value (NPV). Results: The Norwegian Myocardial Infarction Register had a sensitivity of 86.0% (95% confidence interval (CI) 82.8–89.3%), PPV of 97.9% (96.4–99.3%), and specificity of 99.9% and NPV of 98.9% (98.6-99.2%) (99.8–100%). The corresponding figures for the Norwegian Patient Register were 85.8% (95% CI 82.5–89.1%), 95.1% (92.9–97.2%), and 99.7% (99.5–99.8%) and 98.9% (98.6-99.2%), respectively. Both registers had a sensitivity higher than 95% when compared to hospital discharge diagnoses. The results were similar for men and women and for cases below and above 80 years of age. Conclusions: The Norwegian Myocardial Infarction Register and the Norwegian Patient Register are adequately complete and correct for administrative purposes, disease surveillance, quality assessment, and research.

Serum PCSK9 is modified by interleukin-6 receptor antagonism in patients with hypercholesterolaemia following non-ST-elevation myocardial infarction

Objective

It is unclear if activation of inflammatory pathways regulates proprotein convertase subtilisin-kexin type 9 (PCSK9) levels.

Approach

We evaluated (1) the temporal course of serum PCSK9 during hospitalisation following acute coronary syndrome and associations with markers of inflammation (leucocyte counts, interleukin (IL)-6, C-reactive protein) and lipid levels and (2) the effect of inhibition of IL-6 signalling with the IL-6 receptor antibody tocilizumab on PCSK9 levels in a randomised, double-blind, placebo-controlled trial release in patients with non-ST-elevation myocardial infarction.

Results

Serum PCSK9 increased during the acute phase and this response was modestly associated with neutrophil counts (r=0.24, p=0.009) and presence of hypercholesterolaemia (r=0.019, p=0.045), but was not modified by tocilizumab. However, a modifying effect of tocilizumab on PCSK9 levels was observed in patients with hypercholesterolaemia (p=0.024, repeated measures analysis of variance) and this effect was strongly correlated with the decrease in neutrophils (r=0.66, p=0.004).

Conclusions

Our study suggests that patients with a more atherogenic profile may benefit from anti-IL-6 therapy with regard to PCSK9.

Trial registration number

NCT01491074.

IL-6 Receptor Inhibition by Tocilizumab Attenuated Expression of C5a Receptor 1 and 2 in Non-ST-Elevation Myocardial Infarction

Background: Elevated interleukin-6 (IL-6) and complement activation are associated with detrimental effects of inflammation in coronary artery disease (CAD). The complement anaphylatoxins C5a and C3a interact with their receptors; the highly inflammatory C5aR1, and the C5aR2 and C3aR. We evaluated the effect of the IL-6 receptor (IL-6R)-antagonist tocilizumab on the expression of the anaphylatoxin receptors in whole blood from non-ST-elevation myocardial infarction (NSTEMI) patients. Separately, anaphylatoxin receptor expression in peripheral blood mononuclear cells (PBMC) from patients with different entities of CAD was investigated.

Materials and Methods: NSTEMI patients were randomized to one dose of tocilizumab (n = 28) or placebo (n = 32) and observed for 6 months. Whole blood samples drawn at inclusion, at day 2, 3 and after 6 months were used for mRNA isolation. Plasma was prepared for analysis of complement activation measured as sC5b-9 by ELISA. Furthermore, patients with different CAD entities comprising stable angina pectoris (SAP, n = 22), non-ST-elevation acute coronary syndrome (NSTE-ACS, n = 21) and ST-elevation myocardial infarction (STEMI, n = 20) were included. PBMC was isolated from blood samples obtained at admission to hospital and mRNA isolated. Anaphylatoxin-receptor-expression was analyzed with qPCR using mRNA from whole blood and PBMC, respectively.

Results: Our main findings were (i) Tocilizumab decreased C5aR1 and C5aR2 mRNA expression significantly (p < 0.001) and substantially (>50%) at day 2 and 3, whereas C3aR expression was unaffected. (ii) Tocilizumab did not affect complement activation. (iii) In analyzes of different CAD entities, C5aR1 expression was significantly increased in all CAD subgroups compared to controls with the highest level in the STEMI patients (p < 0.001). For C5aR2 and C3aR the expression compared to controls were more moderate with increased expression of C5aR2 in the STEMI group (p < 0.05) and C3aR in the NSTE-ACS group (p < 0.05).

Conclusion: Expression of C5aR1 and C5aR2 in whole blood was significantly attenuated by IL-6R-inhibition in NSTEMI patients. These receptors were significantly upregulated in PBMC CAD patients with particularly high levels of C5aR1 in STEMI patients.

Interleukin-6 receptor inhibition with tocilizumab induces a selective and substantial increase in plasma IP-10 and MIP-1β in non-ST-elevation myocardial infarction

AIM

To evaluate the effect of interleukin-6 inhibition with tocilizumab on the cytokine network in patients with acute non-ST-elevation myocardial infarction (NSTEMI).

METHODS

117 patients with acute NSTEMI were randomised to an intravenous infusion of 280 mg tocilizumab or placebo prior to coronary angiography. Blood samples were obtained at baseline, at 6 consecutive points in time during hospitalisation, and at follow-up after 3 and 6 months. Cytokines (n = 27) were analysed with a multiplex cytokine assay.

RESULTS

Using a mixed between-within subjects analysis of variance, we observed a significant (p < 0.001) between-group difference in changes for interferon gamma-inducible protein (IP-10) and macrophage inflammatory protein-1β (MIP-1β), due to significant increases in the tocilizumab group during hospitalisation (i.e., IP-10 median change from baseline during hospitalisation (m_Δ), placebo: 3 (-60, 68) pg/ml vs tocilizumab: 209 (69, 335) pg/ml; MIP-1β m_Δ, placebo: 5 (-2, 12) pg/ml vs tocilizumab: 39 (24, 63) pg/ml). MIP-1β was inversely correlated to troponin T (r = -0.28, p < 0.05) and neutrophils (r = -0.32, p < 0.05) in the tocilizumab group. In contrast, tocilizumab had only modest or no effects on the other examined cytokines.

CONCLUSIONS

Tocilizumab led to a selective and substantial increase in IP-10 and MIP-1β during the acute phase of NSTEMI, with no or only minor effects on the other measured cytokines. ClinicalTrials.gov, NCT01491074.

Serum lipoprotein(a) is not modified by interleukin-6 receptor antagonism or associated with inflammation in non-ST-elevation myocardial infarction

BACKGROUND

The IL-6 receptor antagonist tocilizumab has been shown to attenuate the proatherogenic lipoprotein a [Lp(a)] in rheumatoid arthritis. We evaluated if a single dose of tocilizumab reduced Lp(a) in patients with non-ST-elevation myocardial infarction (NSTEMI).

METHODS

Lp(a) was assessed by immunoassay (n = 117 patients) at 7 consecutive time-points between day 1 and 3 and at 3 and 6 months follow-up.

RESULTS

Tocilizumab did not affect Lp(a) at any time-point during the study and was not associated with cardiovascular risk factors.

CONCLUSIONS

Short-time inhibition of IL-6 with tocilizumab in patients with NSTEMI did not influence Lp(a) levels.

Human cardiomyocyte calcium handling and transverse tubules in mid-stage of post-myocardial-infarction heart failure

AIMS

Cellular processes in the heart rely mainly on studies from experimental animal models or explanted hearts from patients with terminal end-stage heart failure (HF). To address this limitation, we provide data on excitation contraction coupling, cardiomyocyte contraction and relaxation, and Ca²⁺ handling in post-myocardial-infarction (MI) patients at mid-stage of HF.

METHODS AND RESULTS

Nine MI patients and eight control patients without MI (non-MI) were included. Biopsies were taken from the left ventricular myocardium and processed for further measurements with epifluorescence and confocal microscopy. Cardiomyocyte function was progressively impaired in MI cardiomyocytes compared with non-MI cardiomyocytes when increasing electrical stimulation towards frequencies that simulate heart rates during physical activity (2 Hz); at 3 Hz, we observed almost total breakdown of function in MI. Concurrently, we observed impaired Ca²⁺ handling with more spontaneous Ca²⁺ release events, increased diastolic Ca²⁺ , lower Ca²⁺ amplitude, and prolonged time to diastolic Ca²⁺ removal in MI (P < 0.01). Significantly reduced transverse-tubule density (-35%, P < 0.01) and sarcoplasmic reticulum Ca²⁺ adenosine triphosphatase 2a (SERCA2a) function (-26%, P < 0.01) in MI cardiomyocytes may explain the findings. Reduced protein phosphorylation of phospholamban (PLB) serine-16 and threonine-17 in MI provides further mechanisms to the reduced function.

CONCLUSIONS

Depressed cardiomyocyte contraction and relaxation were associated with impaired intracellular Ca²⁺ handling due to impaired SERCA2a activity caused by a combination of alteration in the PLB/SERCA2a ratio and chronic dephosphorylation of PLB as well as loss of transverse tubules, which disrupts normal intracellular Ca²⁺ homeostasis and handling. This is the first study that presents these mechanisms from viable and intact cardiomyocytes isolated from the left ventricle of human hearts at mid-stage of post-MI HF.

Pedicled Vein Grafts in Coronary Surgery: Perioperative Data From a Randomized Trial

BACKGROUND

Less-than-optimal long-term patency of the saphenous vein is one of the main obstacles for the success of coronary artery bypass grafting (CABG). Results from the IMPROVE-CABG trial has shown that harvesting the saphenous vein with a pedicle of perivascular tissue less than 5 mm while using manual distention provides comparable occlusion rates but significantly less intimal hyperplasia at early follow-up. The impact of pedicled veins on duration of operations, leg wound infections, and postoperative bleeding is unknown.

METHODS

One hundred patients undergoing first-time elective CABG were randomly assigned to conventional or pedicled vein harvesting. Perioperative and postoperative data were collected prospectively during the hospital stay and at follow-up.

RESULTS

Duration of extracorporeal circulation was significantly longer in the pedicled vein group (mean: 76 min versus 65 min, p = 0.006); however, no significant difference was found in the cross-clamp time. No significant difference was found in intraoperative vein graft flow, postoperative bleeding, or leg wound infections (4% in each group). No reoperations were due to vein graft bleeding.

CONCLUSIONS

Harvesting a pedicled vein provides comparable postoperative bleeding and leg wound infection rates in selected patients. The technique is associated with a slightly longer duration of extracorporeal circulation than harvesting conventional veins. Promising early results using the pedicled vein technique may contribute to a change in standard vein harvesting technique for CABG in selected patients.

Effect of interleukin-6 inhibition on coronary microvascular and endothelial function in myocardial infarction

OBJECTIVE

Interleukin-6 (IL-6) is a driver of inflammation and associated endothelial cell activation in acute coronary syndromes. We evaluated the effect of the IL-6 receptor antagonist tocilizumab on coronary microvascular function and endothelial dysfunction measured by coronary flow reserve (CFR) and markers of endothelial cell activation in patients with non-ST-elevation myocardial infarction (NSTEMI).

METHODS

This substudy was part of a two-centre, double-blind, randomised, placebo-controlled trial evaluating the effect of a single dose of tocilizumab in NSTEMI. Markers of endothelial cell activation (vascular cell adhesion molecule (VCAM)-1, intercellular adhesion molecule-1 and von Willebrand factor) were assessed in 117 patients. In 42 of these patients, 20 assigned to placebo and 22 to tocilizumab, we measured CFR. Blood samples were obtained at seven consecutive time points between day 1 and 3. CFR was measured by transthoracic echocardiography during hospitalisation and after 6 months.

RESULTS

Tocilizumab did not affect CFR during hospitalisation (tocilizumab: 3.4±0.8 vs placebo: 3.3±1.2, p=0.80). CFR improved significantly in both groups at 6 months. Patients in the tocilizumab group had significantly higher area under the curve for VCAM-1 (median 622 vs 609 ng/mL/hour, tocilizumab and placebo respectively, p=0.003). There were inverse correlations between VCAM-1 and CFR in the placebo (hospitalisation: r=-0.74, p<0.01, 6 months: r=-0.59, p<0.01), but not in the tocilizumab group (hospitalisation: r=0.20, p=0.37, 6 months r=-0.28, p=0.20).

CONCLUSIONS

Tocilizumab did not affect CFR during hospitalisation or after 6 months. Tocilizumab increased VCAM-1 levels during hospitalisation, but this was not associated with reduced CFR in these patients.

Drug-Eluting or Bare-Metal Stents for Coronary Artery Disease

BACKGROUND

Limited data are available on the long-term effects of contemporary drug-eluting stents versus contemporary bare-metal stents on rates of death, myocardial infarction, repeat revascularization, and stent thrombosis and on quality of life.

METHODS

We randomly assigned 9013 patients who had stable or unstable coronary artery disease to undergo percutaneous coronary intervention (PCI) with the implantation of either contemporary drug-eluting stents or bare-metal stents. In the group receiving drug-eluting stents, 96% of the patients received either everolimus- or zotarolimus-eluting stents. The primary outcome was a composite of death from any cause and nonfatal spontaneous myocardial infarction after a median of 5 years of follow-up. Secondary outcomes included repeat revascularization, stent thrombosis, and quality of life.

RESULTS

At 6 years, the rates of the primary outcome were 16.6% in the group receiving drug-eluting stents and 17.1% in the group receiving bare-metal stents (hazard ratio, 0.98; 95% confidence interval [CI], 0.88 to 1.09; P=0.66). There were no significant between-group differences in the components of the primary outcome. The 6-year rates of any repeat revascularization were 16.5% in the group receiving drug-eluting stents and 19.8% in the group receiving bare-metal stents (hazard ratio, 0.76; 95% CI, 0.69 to 0.85; P<0.001); the rates of definite stent thrombosis were 0.8% and 1.2%, respectively (P=0.0498). Quality-of-life measures did not differ significantly between the two groups.

CONCLUSIONS

In patients undergoing PCI, there were no significant differences between those receiving drug-eluting stents and those receiving bare-metal stents in the composite outcome of death from any cause and nonfatal spontaneous myocardial infarction. Rates of repeat revascularization were lower in the group receiving drug-eluting stents. (Funded by the Norwegian Research Council and others; NORSTENT ClinicalTrials.gov number, NCT00811772 .).

Angiographic and Intravascular Ultrasonographic Findings after Endovascular Stent Implantation

The study was an attempt to evaluate the benefit of intravascular ultrasound imaging (IVUS) as a supplement to follow-up angiography after endovascular stent implantation. A consecutive series of 15 patients underwent stent implantation in the peripheral or coronary arteries. Ten Palmaz stents, 3 Palmaz-Schatz stents and 2 Wallstents were used. After a period from 1 to 6 months (mean 3.2 months) follow-up angiography was performed. In 12 cases the angiography was combined with IVUS of the stent and the adjacent vessel segments. In one case IVUS failed due to the tortuous course of the vessel, in another case the stent was occluded, and in one case IVUS was considered too hazardous. In stents of diameter ≥5 mm, ultrasound (US) did not reveal more information concerning vessel and stent diameter, stent stenosis and intraluminal surface contact than angiography alone. Smaller stents were insufficiently visualized by conventional radiologic methods. In small stents only IVUS permitted an exact stent identification and differentiation between stent stenosis and stenosis of the native vessel. At US imaging artifacts, caused by the highly reflectant metallic stent struts, interfered with the native vessel wall and partly obscured its structural details.