Relationship between treatment delay and type of reperfusion therapy and mechanical complications of acute myocardial infarction

Abstract

Objectives: The incidence of mechanical complications after acute myocardial infarction has markedly declined with the advent of reperfusion. Nevertheless there is some controversy about the equal effectiveness of the different reperfusion therapies in preventing these complications. We aimed to analyse how reperfusion therapy and treatment delay relate to the incidence of mechanical complications in a population of ST-elevation myocardial infarction (STEMI) patients. Methods: We analysed all STEMI patients included in the second phase of the Portuguese Registry on Acute Coronary Syndromes, between October 2010 and July 2015. We compared both conservative medical treatment with reperfusion therapy and thrombolysis with primary percutaneous coronary intervention for mechanical complications. We also evaluated the impact of treatment delay on mechanical complications. Results: Among 5230 STEMIs we observed 77 mechanical complications (1.5%). These were significantly more frequent in the non-reperfused patients (3.3% vs. 1.1%, P<0.001) and they were numerically higher in thrombolysis than in primary percutaneous coronary intervention patients (1.6% vs. 1.0%, respectively, P=0.282). Patients with mechanical complications had higher times from symptom onset to hospitalisation and to reperfusion. In multivariate analysis performing reperfusion therapy (odds ratio 0.52, 95% confidence interval 0.29-0.93) and a time from symptom onset to hospitalisation ⩾6 hours (odds ratio 2.44, 95% confidence interval 1.37-4.33) were independent predictors of mechanical complications. The type of reperfusion did not influence the occurrence of mechanical complications. Conclusion: A longer time from symptom onset to hospitalisation was associated with an increased number of mechanical complications. Timely reperfusion therapy prevented mechanical complications and no significant difference was found between thrombolysis and primary percutaneous coronary intervention.