Background: Mechanical complications represent an important cause of mortality in myocardial infarction (MI) patients. This is a nationwide study performed to evaluate possible changes in epidemiology or prognosis of these complications with current available strategies.
Methods: Information was obtained from the minimum basis data set of the Spanish National Health System, including all hospitalizations for acute myocardial infarction (AMI) from 2010 to 2015. Risk-standardized in-hospital mortality ratio was calculated using multilevel risk adjustment models.
Results: A total of 241,760 AMI episodes were analyzed, MI mechanical complications were observed in 842 patients: cardiac tamponade in 587, ventricular septal rupture in 126, and mitral regurgitation due to papillary muscle or chordae tendineae rupture in 155 (there was more than one complication in 21 patients). In-hospital mortality was 59.5%. On multivariate adjustment, variables with significant impact on in-hospital mortality were: age (OR 1.06; 95% CI 1.04-1.07; p < 0.001), ST-segment elevation AMI (OR 2.91; 95% CI 1.88-4.5; p < 0.001), cardiogenic shock (OR 2.35; 95% CI 1.66-3.32; p < 0.001), cardio-respiratory failure (OR 3.48; 95% CI 2.37-5.09; p < 0.001), and chronic obstructive pulmonary disease (OR 1.85; 95% CI 1.07-3.20; p < 0.001). No significant trends in risk-adjusted in-hospital mortality were detected (IRR 0.997; p = 0.109). Cardiac intensive care unit availability and more experience with mechanical complications management were associated with lower adjusted mortality rates (56.7 ± 5.8 vs. 60.1 ± 4.5; and 57 ± 6.1 vs. 59.9 ± 5.6, respectively; p < 0.001).
Conclusions: Mechanical complications occur in 3.5 per thousand AMI, with no significant trends to better survival over the past few years. Advanced age, cardiogenic shock and cardio-respiratory failure are the most important risk factors for in-hospital mortality. Higher experience and specialized cardiac intensive care units are associated with better outcomes.
Keywords: cardiac tamponade; mechanical complications; myocardial infarction; papillary muscle rupture; ventricular septal rupture.