Non-culprit MACE-rate in LRP: The influence of optimal medical therapy using DAPT and statins

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.

Association of Statins With Nonculprit Coronary Lesions and Adverse Events (from the LRP Study)

Intravascular ultrasound and near-infrared spectroscopy can identify vulnerable coronary atherosclerotic plaques. In this LRP (Lipid-Rich Plaque) substudy, we evaluated the association of statins with nonculprit lesion arterial wall lipidic content and subsequent nonculprit major adverse cardiac events. Patients from the LRP study with known statin use were included. We divided the patients into 2 cohorts-"statin therapy" and "statin-naïve"-upon presentation and then described the intravascular ultrasound and near-infrared spectroscopy analysis based on maximum 4-mm lipid core burden index (maxLCBI_4mm). At 2-year follow-up, the patients' clinical events were assessed based on their statin regimen change upon discharge. Finally, patients were stratified by statin intensity based on discharge regimen. Among the 1,526 patients, 1,120 were on a statin versus 396 who were statin-naive upon presentation. Patients on a statin at baseline had a statistically higher rate of cardiovascular risk factors, patients who were statin-naive were more likely to present with an acute coronary syndrome, and the maxLCBI_4mm did not differ between the 2 groups (315.67 ± 181.36 vs 325.55 ± 192.16; p = 0.359). These findings were consistent in a secondary analysis evaluating statin intensity. Patients who were switched from no statin to a statin had improved outcomes (nonculprit major adverse cardiac events) compared with patients who were on a statin at baseline without change. In conclusion, despite having a higher burden of nonlipid-related cardiac co-morbidities, patients on a statin at baseline had similar maxLCBI_4mm with patients who were statin-naive, regardless of intensity. Initiating a statin at discharge provides the most benefit for events related to nonculprit lesions.

Additive Effect of Multiple High-Risk Coronary Artery Segments on Patient Outcomes: LRP Study Sub-Analysis

BACKGROUND

The Lipid Rich Plaque (LRP) Study established the association between high volume of lipidic content (maximum Lipid Core Burden Index [maxLCBI_4mm] >400) in the coronary arteries and subsequent non-culprit major adverse cardiac events (NC-MACE). This analysis sought to assess the clinical impact of more than one lipid-rich plaque in the coronary tree.

METHODS

The LRP patient population was divided into four cohorts: 1) patients with all segments with maxLCBI_4mm = 0; 2) patients with all coronary segments maxLCBI_4mm < 400, but >0; 3) patients with 1 segment maxLCBI_4mm > 400; and 4) patients with 2+ coronary segments with maxLCBI_4mm > 400. Baseline characteristics, plaque-level characteristics, and follow-up outcomes were described.

RESULTS

Among 1550 patients, only 3.2 % had all segments with maxLCBI_4mm = 0; 65.1 % had segments with maxLCBI_4mm > 0 but <400; 22.5 % had one segment with maxLCBI_4mm > 400; and 9.5 % had 2+ coronary segments with maxLCBI_4mm > 400. Distribution within the coronary tree (one versus multiple arteries) did not differ. Overall, 1269 patients were allocated to follow-up (per study design). The composite of all-cause death, cardiac death, any revascularization, and NC-MACE was statistically higher in patients with 1 segment maxLCBI_4mm > 400 and numerically even higher in patients with 2+ segments with maxLCBI_4mm > 400. Patients with maxLCBI_4mm = 0 had no events within two years.

CONCLUSION

There is a stepwise increased risk of all-cause death, cardiac death, any revascularization, and NC-MACE according to the number of coronary segments with maxLCBI_4mm > 400. In contrast, maxLCBI_4mm = 0 results in a low event rate.

CLINICAL TRIAL REGISTRATION

The Lipid-Rich Plaque Study (LRP), https://clinicaltrials.gov/ct2/show/NCT02033694, NCT02033694.