Impact of Collateral Circulation on Survival in ST-Segment Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention With a Concomitant Chronic Total Occlusion.

OBJECTIVES: This study sought to compare long-term clinical outcome in ST-segment elevation myocardial infarction (STEMI) patients with a concomitant chronic total occlusion (CTO) with well-developed versus poorly developed collaterals toward the CTO.

BACKGROUND: In STEMI patients, presence of a CTO is associated with increased morbidity and mortality. CTOs are often (partially) perfused by collateral vessels. Therefore, when the infarct-related artery (IRA) is the main donor vessel for the collateral blood supply of the CTO, infarct size may increase significantly. Well-developed collaterals to the infarct related vessel have been associated with improved clinical outcome after STEMI. However, the impact of well-developed collaterals toward a concomitant CTO in STEMI patients is unknown.

METHODS: Consecutive STEMI patients with a CTO in a non-IRA presenting for primary percutaneous coronary intervention (PCI) were divided according to the presence of angiographic, well-developed (grade 2 to 3) or poorly developed collaterals (grade 0 to 1).

RESULTS: Between 2000 and 2012 we included 413 STEMI patients with a single concomitant CTO. Well-developed collaterals to the CTO were present in 53%. Associated with poorly developed collaterals to the CTO were cardiogenic shock (hazard ratio [HR]: 1.8; 95% confidence interval [CI]: 1.11 to 3.07; p = 0.02), CTO located in the left circumflex artery (HR: 1.9; 95% CI: 1.00 to 3.43; p = 0.05), CTO diameter ≤2.5 mm (HR: 2.1; 95% CI: 1.07 to 4.12; p = 0.03), and CTO tapering (HR: 1.9; 95% CI: 1.21 to 2.85; p < 0.001). Patients with well-developed collaterals to the CTO had a better 5-year survival compared to those with poorly developed collaterals (74% vs. 63%; p = 0.01). The presence of well-developed collaterals to the CTO was independently associated with improved survival (HR: 1.5; 95% CI: 1.03 to 2.10; p = 0.04).

CONCLUSIONS: In STEMI patients with a CTO in a non-IRA, the presence of well-developed collaterals to the CTO is associated with improved survival.