Why some patients with SCAD develop recurrent coronary or extra-coronary complications remains unclear. The ISCAD-CATCH multicenter observational study, published in the International Journal of Cardiology, evaluated clinical characteristics and medical therapy associated with MADCE in Japanese patients with SCAD.

Among 566 patients with SCAD followed for a median of 1,490 days, MADCE occurred in 13.4%. Events included cardiac death in 1.2%, recurrent SCAD in 10.9%, and symptomatic extra-coronary artery dissection in 1.6%. Patients who experienced MADCE were younger than those without events (47.5 ± 10.5 vs 51.0 ± 10.7 years; P = 0.006).

Differences in medical therapy were observed between groups. Calcium-channel blockers were used more frequently in patients with MADCE than in those without events (53.9% vs 39.2%; P = 0.015). β1-selective blockers were used less frequently in patients with MADCE (18.4% vs 33.7%; P = 0.008).

In multivariable analysis, younger age was independently associated with higher MADCE risk (hazard ratio [HR] 0.975; 95% confidence interval [CI] 0.953 to 0.997; P = 0.029). Use of β1-selective blockers was associated with lower risk (HR 0.520; 95% CI 0.279 to 0.967; P = 0.039), while calcium-channel blocker use was associated with higher risk (HR 1.682; 95% CI 1.051 to 2.691; P = 0.030). MADCE incidence increased to 30.6% in patients younger than 50 years who were not treated with β1-selective blockers and received calcium-channel blockers (HR 3.215; 95% CI 2.000 to 5.166; P < 0.001).