Coronary Atherosclerotic Plaque Characteristics and Cardiovascular Risk Factors　- Insights From an Optical Coherence Tomography Study.

BACKGROUND: The association between cardiovascular risk factors (CVRF) and the risk of coronary events is widely acknowledged. Whether individual risk factors may be associated with distinct plaque characteristics is currently unclear. We investigated the relationship between CVRF and coronary plaque burden and phenotype.Methods and Results:We assessed coronary atherosclerotic plaque characteristics by optical coherence tomography in 67 patients with stable coronary artery disease undergoing coronary angiography. The plaque burden and the distinct plaque phenotypes were compared with regard to different CVRF. Overall plaque burden was significantly greater in patients with diabetes mellitus (P=0.010), prediabetes (P=0.035) and obesity (P=0.024), and correlated with the number of CVRF (R=0.358, P=0.003). Patients with diabetes had a greater extent of fibroatheroma (P=0.015), calcific fibroatheroma (P=0.031), thin-cap fibroatheroma (TCFA-P=0.011) and plaque erosion (P=0.002). Obese patients showed a greater extent of fibroatheroma (P=0.007), TCFA (P=0.015) and macrophage load (P=0.043). The number of CVRF correlated with fibroatheroma (R=0.425, P<0.001), calcific fibroatheroma (R=0.321, P=0.008), TCFA (R=0.347, P=0.004), macrophage load (R=0.314, P=0.010) and erosion (R=0.271, P=0.029). In the multivariate analysis, altered glycemic status and obesity were the only independent predictors of TCFA (P=0.026 and P=0.046, respectively), whereas altered glycemic status was the only independent predictor of plaque erosion (P=0.001). CONCLUSIONS: Patients with diabetes, prediabetes and obesity show more extensive coronary atherosclerosis and more vulnerable plaque phenotypes.

Transcoronary gradients of vascular miRNAs and coronary atherosclerotic plaque characteristics.

AIMS: Circulating microRNAs (miRs) may reflect pathophysiologically relevant processes in the atherosclerotically diseased coronary arterial wall. Given the unmet medical need to identify patients with an unstable plaque phenotype, we determined the relation of circulating atherosclerosis-regulatory miRs with plaque phenotypes. METHODS AND RESULTS: We assessed coronary atherosclerotic plaque burden and phenotype by optical coherence tomography in 52 patients and measured the levels of circulating miRs across the transcoronary gradient. The overall plaque load was significantly correlated with transcoronary concentration gradients of miR-126-3p (P = 0.04), miR-145-5p (P = 0.01), miR-155-5p (P < 0.01), and miR-29b-3p (P = 0.02), but not with other miRs such as miR-92a-3p. In patients with a high extent of vulnerable plaques as assessed by the presence of thin-cap fibroatheromas (TCFAs), significantly higher transcoronary gradients were observed, particularly for miR-126-3p, miR-126-5p, and miR-145-5p (all P < 0.02). Transcoronary gradients of miR-126-3p (P < 0.01), miR-126-5p (P < 0.01), miR-145-5p (P = 0.01), miR-29b-3p (P = 0.03), and miR-155-5p (P = 0.02) demonstrated a significant discriminatory power to predict the presence of TCFAs (AUC > 0.7 for all). Moreover, aortic and venous coronary sinus levels of miR-29b-3p were inversely correlated with plaque fibrosis, a finding that is consistent with the anti-fibrotic activity of miR-29b-3p. CONCLUSION: The overall plaque burden and plaque phenotypes are associated with changes in the kinetics of miR-concentrations across the transcoronary passage. Transcoronary gradients of the anti-atherosclerotic miR-126-3p and miR-145-5p correlated with the extent of TCFAs, suggesting that instable plaques may affect the local uptake or degradation of these miRs.

Estimation of Values below the Limit of Detection of a Contemporary Sensitive Troponin I Assay Improves Diagnosis of Acute Myocardial Infarction.

BACKGROUND: The limit of detection (LoD) is the minimal amount of a substance that can be consistently detected. In the diagnosis of acute myocardial infarction (AMI) many patients present with troponin concentrations below the LoD of contemporary sensitive cardiac troponin I (cs-cTnI) assays. These censored values below the LoD influence the diagnostic performance of these assays compared to highly sensitive cTnI (hs-cTnI) assays. Therefore we assessed the impact of a new approach for interpolation of the left-censored data of a cs-cTnI assay in the evaluation of patients with suspected AMI. METHODS: Our posthoc analysis used a real world cohort of 1818 patients with suspected MI. Data on cs-cTnI was available in 1786 patients. As a comparator the hs-cTnI version of the assay was used. To reconstruct quantities below the LoD of the cs-cTnI assay, a gamma regression approach incorporating the GRACE (Global Registry of Acute Coronary Events) score variables was used. RESULTS: Censoring of cs-cTnI data below the LoD yielded weaker diagnostic information [area under the curve (AUC), 0.781; 95% CI, 0.731-0.831] regarding AMI compared to the hs-cTnI assay (AUC, 0.949; CI, 0.936-0.961). Use of our model to estimate cs-cTnI values below the LoD showed an AUC improvement to 0.921 (CI, 0.902-0.940). The cs-cTnI LoD concentration had a negative predictive value (NPV) of 0.950. An estimated concentration that was to be undercut by 25% of patients presenting with suspected AMI was associated with an improvement of the NPV to 0.979. CONCLUSIONS: Estimation of values below the LoD of a cs-cTnI assay with this new approach improves the diagnostic performance in evaluation of patients with suspected AMI.