Angiographic classification and clinical outcomes of spontaneous coronary artery dissection in Japanese patients: Insights from a multicenter registry

Background Spontaneous coronary artery dissection (SCAD) is characterized by separation of the coronary arterial wall due to intramural hematoma, with or without an intimal tear, and is angiographically classified into four types (Types 1–4, Figure 1). Although this classification is widely used for diagnosis, its prognostic implications remain unclear, particularly in Asian populations. Purpose To evaluate the association between angiographic classification and clinical outcomes in Japanese patients with SCAD. Methods This multicenter registry included 175 patients with SCAD enrolled at 15 participating centers in Japan between 2021 and 2025. Patients were classified into four groups according to angiographic morphology. Baseline characteristics and in-hospital clinical outcomes were compared among angiographic types using appropriate statistical analyses. The primary endpoint was a composite of in-hospital adverse events including heart failure, cardiogenic shock, sustained ventricular tachycardia/ventricular fibrillation, recurrence of SCAD, and death. Results Among 175 patients, 148 (84.6%) were female, and the mean age was 51.6 ± 10.0 years. Angiographic classification revealed 17 patients (9.7%) with Type 1 lesions, 73 (41.7%) with Type 2a, 35 (20.0%) with Type 2b, 12 (6.9%) with Type 3, and 39 (22.3%) with Type 4 lesions (Figure 1). A composite of in-hospital adverse events occurred in 14.3% of all patients (Figure 2): 11.7% in Type 1, 20.5% in Type 2a, 8.6% in Type 2b, 16.7% in Type 3, and 7.7% in Type 4 lesions, which differed across angiographic types. Early recurrent SCAD due to extension of the original dissection occurred in 5 patients, of whom 4 (80.0%) had Type 2a lesions. Type 2a morphology showed a numerically higher rate of in-hospital composite events compared with other angiographic types (odds ratio 2.38, p=0.07). When stratified by TIMI flow grade, 76 patients had TIMI 3 flow and 93 had TIMI <3 flow (6 classified as unknown or overlapping). The in-hospital adverse events occurred in 17.1% of patients with TIMI 3 flow and 9.7% with TIMI <3 flow (odds ratio 1.93, p=0.23), indicating that preserved TIMI 3 flow did not confer a lower in-hospital risk. Conclusions Type 2a angiographic morphology may be associated with a higher propensity for lesion extension and in-hospital adverse events in patients with SCAD. Unlike acute myocardial infarction, preserved TIMI 3 flow in SCAD does not necessarily indicate a favorable in-hospital clinical course.Figure1Figure2