BACKGROUND: The presence of collateral circulation in the context of acute myocardial infarction (AMI) may play a protective role, leading to smaller infarction areas and improved ventricular function. This study was aimed at assessing the clinical characteristics of patients with different degrees of collateral circulation and the effect on outcomes of ST segment elevation AMI (STEMI) complicated by cardiogenic shock at hospital admission and treated by primary percutaneous coronary intervention (PCI). METHODS: Single center registry with a prospective follow-up from 2001 to 2009, including 105 patients divided into two groups, according to the degree of collateral circulation: Group 1, collateral circulation grades 0/1 (n = 83); and Group 2, collateral circulation grades 2/3 (n = 22). Clinical and angiographic characteristics and hospital outcomes were compared between groups. RESULTS: The clinical characteristics of both groups were similar, except for a lower mean age (65.9 years vs. 57.8 years; P = 0.015) and a trend to current smoking in the grade 2/3 group (15.7% vs. 31.8%; P = 0.08). As to angiographic characteristics, individuals with grades 2/3 had a higher rate of lesions per patient (1.3 vs. 1.8; P = 0.02) and more bifurcation lesions (18.5% vs. 36.4%; P = 0.03). In-hospital outcomes showed lower mortality in patients with good collateral circulation (49.4% vs. 27.3%, relative risk 0.55; P = 0.05). CONCLUSIONS: In patients with STEMI and cardiogenic shock treated by primary PCI, the presence of collateral circulation may improve in-hospital prognosis.
Angioplasty; Myocardial infarction; Shock, cardiogenic; Collateral circulation
