Abstract 14370: Significant Heterogeneity in Antiplatelet Regimen for Spontaneous Coronary Artery Dissection: A Report of the ISCAD Registry

Introduction: Dual antiplatelet therapy (DAPT) is standard for patients (pts.) with acute coronary syndrome due to atherosclerosis. Evidence to support DAPT vs single antiplatelet therapy (SAPT) for spontaneous coronary artery dissection (SCAD) is limited. Hypothesis: Prescription of DAPT vs SAPT varies among specialized centers for SCAD. Methods: Analysis of 505 pts. with complete patient questionnaire, case report form, and angiography review enrolled in the iSCAD Registry from 9 sites with > 20 pts. enrolled. Data are presented for 442 pts. with complete medication data who received DAPT or SAPT during index hospitalization (HOSP) and continued at discharge (DC). Results: Patient age 49.6 + 10.2 years, 83% were female. Presentation of SCAD: NSTEMI (55.9%), STEMI (26.9%), unstable angina (13.8%), cardiac arrest (4.3%), cardiogenic shock (0.2%). Most common SCAD location was the LAD (60.9%); 20.8% had multivessel SCAD. Management was: medical therapy (75.2%), PCI (22.5%), CABG (1.4%), or PCI + CABG (0.92%). During HOSP 70.1% (317/452) were treated with DAPT vs 29.9% SAPT (135/452). At DC, 74.7% were prescribed DAPT (339/442) vs 25.3% SAPT (112/452). In multivariable analyses, only PCI as SCAD treatment was associated with DAPT during HOSP (OR 3.57, 95% CI 1.90-6.70) or DC (OR 4.9, 95% CI 2.28-10.53). There was significant heterogeneity of antiplatelet regimen across sites ranging from 34.0%-87% DAPT during HOSP (p<0.0001) and 53.8%-83.6% DAPT at DC (p=0.0011) (Figure). There was a trend of recurrent MI among pts. treated with DAPT vs SAPT during HOSP that did not achieve statistical significance (7.1% vs 3.0%, P=0.09). Conclusion: In the iSCAD Registry, most pts. with SCAD were treated with DAPT during index HOSP and DC with significant heterogeneity across sites. PCI during index HOSP was associated with DAPT (vs SAPT) prescription. Further study of outcomes, including recurrent MI, with DAPT (vs SAPT) during hospitalization and subsequent follow-up is needed.