Impact of coronary collaterals on in-hospital and 5-year mortality after ST-elevation myocardial infarction in the contemporary percutaneous coronary intervention era: a prospective observational study

OBJECTIVES: To evaluate the short-term and long-term prognostic impacts of acute phase coronary collaterals to occluded infarct-related arteries (IRA) after ST-elevation myocardial infarction (STEMI) in the percutaneous coronary intervention (PCI) era. DESIGN: A prospective observational study. SETTING: Osaka Acute Coronary Insufficiency Study (OACIS) in Japan. PARTICIPANTS: 3340 patients with STEMI from the OACIS database who were admitted to hospitals within 24 hours from the onset and who had a completely occluded IRA. INTERVENTIONS: Patients were divided into 4 groups according to the Rentrop collateral score (RCS) by angiography on admission (RCS-0, no visible collaterals; RCS-1, collaterals without IRA filling; RCS-2, collaterals with partial IRA filling; and RCS-3, collaterals with complete IRA filling). PRIMARY OUTCOME MEASURES: In-hospital and 5-year mortality. RESULTS: Patients with RCS-0/3 were older than patients with RCS-1/2, and the prevalence of previous myocardial infarction was highest in patients with RCS-3. Median peak creatinine phosphokinase levels decreased as RCS increases (p<0.001), suggesting the acute cardioprotective effects of collaterals. Although RCS-1 and RCS-2 collaterals were associated with better in-hospital mortality (adjusted OR 0.48, p=0.046 and 0.38, p=0.010 for RCS-1 and RCS-2, respectively) and 5-year mortality (adjusted HR 0.53, p=0.004 and 0.46, p<0.001 for RCS-1 and RCS-2, respectively) as compared with R-0, presence of RCS-3 collaterals was not associated with improved in-hospital (adjusted OR 1.35, p=0.331) and 5-year mortality (adjusted HR 0.98, p=0.920), possibly because worse clinical profiles in patients with RCS-3 may mask mortality benefit of coronary collaterals. CONCLUSIONS: Presence of acute phase coronary collaterals such as RCS-1 and RCS-2 were associated with better in-hospital and 5-year mortality after STEMI in the contemporary PCI era.