Background: Mechanical complications of acute myocardial infarction (MI) still contribute significantly to infarct-related mortality. Evidence regarding epidemiology, management strategies including advanced circulatory support, and surgical or catheter-based repair, outcomes, and risk factors associated with mortality is limited.
Methods: The international Mechanical complications of Acute Myocardial Infarction (MIAMI) study was conducted to analyze the clinical course and current management strategies, and to optimize risk stratification in patients with (I) MI-associated papillary muscle rupture (PMR), (II) ventricular septal rupture (VSR), and (III) ventricular free wall rupture (VFWR). Data from adult patients admitted between January 2013 and December 2023 were collected from 35 European tertiary centers. Inverse probability weights (IPW) for complication types were estimated using multinomial logistic regression models with covariate balance being assessed through standardized mean differences for weighted and unweighted comparisons. Associations of pre-specified risk factors with in-hospital mortality were assessed using a multivariable mixed-effects logistic regression model and a secondary interaction model designed to investigate variations of mortality predictors across complication types.
Results: A total of 1,003 patients with mechanical complications of acute MI were included and analyzed, including 240 with PMR, 473 with VSR, 254 with VFWR, and 36 with multiple mechanical complications. The median age in the overall study population was 69 years (interquartile range 61-77 years), 61.5% were male, and 82.8% presented with ST-elevation MI (STEMI). Patients with PMR, VSR, and VFWR differed in demographics, baseline clinical status, and management strategies – particularly in the proportions undergoing surgical correction (82.5%, 67.4%, and 49.6%, respectively), interventional repair (4.2%, 14.0%, and 0%), and mechanical circulatory support (65.4%, 71.5%, and 26.8%). The overall in-hospital mortality was 51.2%. Weighted in-hospital mortality rates of patients with PMR, VSR, and VFWR were 43.0%, 52.1%, and 52.7%, respectively (maximum standardized mean difference 0.098). Factors independently associated with mortality were age, sex, body mass index, STEMI, cardiogenic shock, and out-of-hospital cardiac arrest. The strengths of associations of age, sex, body mass index, STEMI and out-of-hospital cardiac arrest varied across complication types.
Conclusion: Mechanical complications of acute MI continue to be associated with high mortality. Substantial differences between subgroups regarding the clinical course and prognostic factors highlight the need for individualized risk stratification and further evidence to inform the orchestration of advanced treatment strategies.
