Coronary Atherosclerotic Phenotype and Plaque Healing in Patients With Recurrent Acute Coronary Syndromes Compared With Patients With Long-term Clinical Stability: An In Vivo Optical Coherence Tomography Study

IMPORTANCE At one end of the coronary artery disease (CAD) spectrum, there are patients with multiple recurrent acute coronary syndromes (rACS), and at the other end there are those with long-standing clinical stability. Predicting the natural history of these patients is challenging because unstable plaques often heal without resulting in ACS.OBJECTIVE To assess in vivo the coronary atherosclerotic phenotype as well as the prevalence and characteristics of healed coronary plaques by optical coherence tomography (OCT) imaging in patients at the extremes of the CAD spectrum.DESIGN, SETTING, AND PARTICIPANTS This is an observational, single-center cohort study with prospective clinical follow-up. From a total of 823 consecutive patients enrolled inOCTRegistry of the Fondazione PoliclinicoA. Gemelli-IRCCS, Rome, Italy, from March 2009 to February 2016, 105 patients were included in the following groups: (1) patients with rACS, defined as history of at least 3 acutemyocardial infarctions (AMIs) or at least 4ACS with at least 1 AMI; (2) patients with long- standing stable angina pectoris (ls-SAP), defined as a minimum 3-year history of stable angina; and (3) patients with a single unheralded AMI followed by a minimum 3-year period of clinical stability (sAMI). Data were analyzed from January to August 2018.EXPOSURES Intracoronary OCT imaging of nonculprit coronary segments.MAIN OUTCOMES AND MEASURES Coronary plaque features and the prevalence of healed coronary plaques in nonculprit segments as assessed by intracoronary OCT imaging.RESULTS Of 105 patients, 85 were men (81.0%); the median (interquartile range) age was 68 (63-75) years. Median (interquartile range) time of clinical stability was 9 (5.0-15.0) years in the ls-SAP group and 8 (4.5-14.5) years in the sAMI group. Patients in the rACS and sAMI groups showed similar prevalence of lipid-rich plaque and thin-cap fibroatheroma, which was significantly higher than in those with ls-SAP (lipid-rich plaque 80.0%[n = 24 of 30] vs 76.3% [n = 29 of 38] vs 37.8%[n = 14 of 37], respectively; P <.001; thin- cap fibroatheroma 40.0% [n = 12 of 30] vs 34.2%[n = 13 of 38] vs 8.1% [n = 3 of 37], respectively; P =.006). Spotty calcifications were more frequently observed in patients with rACS than in those with ls- SAP and sAMI (70.0%[n = 21 of 30] vs 40.5%[n = 15 of 37] vs 44.7%[n = 17 of 38], respectively; P =.04). Healed coronary plaques were rarely observed in patients with rACS, whereas their prevalence was significantly higher in patients with ls-SAP and sAMI (3.3%[n = 1 of 30] vs 29.7%[n = 11 of 37] vs 28.9%[n = 11 of 38], respectively; P = .01).CONCLUSIONS AND RELEVANCE Patients with rACS have a distinct atherosclerotic phenotype compared with those with ls-SAP, including higher prevalence of thin-cap fibroatheroma and lower prevalence of healed coronary plaques, suggesting that atherosclerotic profile and plaque healingmay play a role in leading the natural history of patients with CAD.