Comparison of Coronary Culprit Lesion Morphology Determined by Optical Coherence Tomography and Relation to Outcomes in Patients Diagnosed with Acute Coronary Syndrome During Winter -vs- Other Seasons.

Patients diagnosed with acute coronary syndrome (ACS) during winter have worse outcomes; however, mechanisms driving this trend are unclear. We examined coronary culprit lesion morphologies using optical coherence tomography (OCT). Features and outcomes were retrospectively compared between patients admitted with ACS in winter (W-ACS; n = 390) and in other seasons (O-ACS; n = 1,027). Angiography and OCT results were analyzed in patients who underwent OCT examination (173 patients in W-ACS and 450 in O-ACS). On initial angiography, minimum lumen diameter was smaller (median; 0.12 mm vs 0.25 mm, p = 0.021) and Thrombolysis in myocardial infarction flow grade was worse (Thrombolysis in myocardial infarction 0/1; 57% vs 44%, p = 0.005) in W-ACS. OCT performed before coronary interventions or just after intracoronary thrombectomy showed that plaque rupture (56% vs 46%) and calcified nodules (8% vs 5%) were more prevalent, and plaque erosion (37% vs 49%) was less prevalent in W-ACS (p = 0.039 for all 3 variables). At 2-year follow-up for all admitted ACS patients, Kaplan-Meier estimates showed higher cardiac mortality in W-ACS (11.8% vs 8.3%, p = 0.043). Multivariate Cox proportional hazard analysis showed that patients in W-ACS group had a 1.5-fold increased risk of cardiac death within 2 years after adjusting for traditional cardiovascular risk factors (hazard ratio, 1.54 [95% confidence interval, 1.06 to 2.23]; p = 0.024). In conclusion, patients diagnosed with ACS during winter had worse angiographic results and OCT revealed less plaque erosion (more plaque rupture or calcified nodules) at the culprit lesions, which may be partly associated with worse cardiac mortality within 2 years.