Background: The positive impact of coronary collateral vessels in the acute phase of myocardial infarction (AMI) is already well established. However, their impact on longterm clinical outcome of these patients is still unclear.
Aim: To study the impact of the presence of well established coronary collateral vessels on long-term clinical outcome of post-AMI patients.
Population and methods: We analyzed the clinical evolution (mean follow-up time of 15.66.8 months) of 70 patients who underwent coronary angiography shortly after AMI. According to the angiogram, the patients were divided into 2 groups: those with well developed coronary collateral vessels (n = 35) and those who did not show developed collateral circulation (n = 35).
Results: Both groups had similar baseline characteristics (regarding demography, coronary artery disease risk factors and predischarge evolution). The group with collaterals had more severe coronary disease compared with the group without collaterals (2.31 +/- 0.61 vs. 1.57 +/- 0.7; p = 0.00001). Moreover, this group more frequently showed significant lesions on the left anterior descending artery (83% vs. 74%; p = NS), left circumflex (71% vs. 43%; p = 0.02) and right coronary arteries (74% vs. 40%; p = 0.003). Primary percutaneous coronary intervention was more often performed in patients without coronary collateral vessels (58% vs. 30%; p = 0.02). Left ventricular function was similar in both groups. During follow-up, both groups underwent similar levels of revascularization by percutaneous coronary intervention and/or coronary artery bypass graft (70% vs. 76%; p = NS). Despite these characteristics, the group with collaterals showed a significantly better clinical outcome, with fewer events (combined endpoint of unstable angina, non-fatal AMI, heart failure and death) after hospital discharge (40% vs. 69%; p = 0.02) and a lower CCS functional class at the end of follow-up (1.26 +/- 0.63 vs. 1.730.71; p = 0.03).
Conclusion: After acute myocardial infarction, the presence of collateral vessels is associated with a better long-term clinical outcome.