Markis type 4 coronary ectasia aligned with the lowest long-term ischemic and bleeding event rates following acute coronary syndrome. The retrospective cohort included 507 patients diagnosed with acute coronary syndrome and angiographic coronary ectasia between January 2001 and December 2021. Re-infarction and hemorrhagic events were tracked until the last clinic or emergency department visit. Event-free survival was calculated using Kaplan–Meier analysis, and the log-rank method compared risk across Markis types. The mean follow-up period was 31.4 months, ranging from 4.3 to 53.8 months.

During five years, 46 patients (9%) experienced re-infarction. Ectatic culprit vessels appeared in 34 of these cases. Compared with Markis type 1, the hazard ratio for re-infarction was 0.43 for type 2 (P = 0.12) and 0.12 for type 4 (P = 0.04). Hemorrhagic events occurred in 51 patients (10%), including 27 moderate to severe bleeds. Compared with type 1, the hazard ratio for hemorrhage was 0.33 for type 2 (P = 0.40), 1.09 for type 3 (P = 0.80), and 0.10 for type 4 (P = 0.025).

These findings indicate that the extent of coronary ectasia, as categorized by the Markis system, may support long-term risk assessment after acute coronary syndrome. Patients with Markis type 4 demonstrate a distinctly favorable ischemic and bleeding profile.