GENDER-BASED INCIDENCE OF MECHANICAL COMPLICATIONS AFTER ACUTE MYOCARDIAL INFARCTION AT A TERTIARY CARE HOSPITAL

Abstract

Background: Mechanical complications of acute myocardial infarction (AMI), including ventricular septal rupture (VSR), papillary muscle rupture (PMR) causing acute severe mitral regurgitation, and left ventricular free wall rupture (LVFWR), are among the most catastrophic consequences of transmural myocardial necrosis. Although their incidence has declined in high-income countries with the widespread adoption of primary percutaneous coronary intervention (PCI), these complications remain associated with extremely high short-term mortality. In low-and middle-income countries (LMICs), such as Pakistan, where reperfusion therapy may be delayed or unavailable, the burden of mechanical complications may be substantially higher. Sex differences in AMI presentation, management, and outcomes are well recognized; however, data on sex-based differences in mechanical complications from South Asian populations remain scarce. This study aimed to determine the sex-based incidence of mechanical complications among patients admitted with AMI at Lady Reading Hospital (LRH), Peshawar, a major tertiary care center in Khyber Pakhtunkhwa, Pakistan.

Methods: A descriptive cross-sectional study was conducted on 140 adult patients admitted with AMI (STEMI or NSTEMI) to the cardiology department of LRH during the data collection period. Patients aged ≥ 18 years with a confirmed AMI diagnosis based on clinical features, electrocardiographic changes, and elevated cardiac biomarkers, and with complete clinical and echocardiographic records, were included. Patients with pre-existing structural heart disease were excluded. Data were collected using a structured proforma encompassing demographic characteristics, cardiovascular risk factors, AMI type, echocardiographic findings, laboratory values, management strategies, and in-hospital outcomes. Mechanical complications were defined as new-onset VSR, PMR causing acute severe mitral regurgitation, or LVFWR occurring during the index hospitalization. Data were entered and analyzed using SPSS version 27. Descriptive statistics were used to summarize the baseline characteristics. Chi-square tests and two-proportion Z tests were used to assess the associations between categorical variables. A p-value of less than 0.05 was considered statistically significant.

Results: The study population comprised 86 men (61.4%) and 54 women (38.6%), with a mean age of 56.5 ± 11.2 years. STEMI was diagnosed in 72 patients (51.4%) and NSTEMI in 68 patients (48.6%). The most prevalent cardiovascular risk factors were hypertension (62.1%), diabetes mellitus (48.6%), and smoking (41.4%). Mechanical complications were documented in 48 patients (34.3%): papillary muscle rupture in 20 patients (41.7% of complicated cases), ventricular septal rupture in 16 patients (33.3%), and left ventricular free wall rupture in 12 patients (25.0%). Sex was not significantly associated with the occurrence of mechanical complications (χ² = 0.130, p = 0.718; Z = −0.544, p = 0.587). AMI type, diabetes, smoking, hyperlipidemia, and a family history of ischemic heart disease were also not significantly associated with mechanical complications. However, there was a strong and statistically significant association between mechanical complications and in-hospital outcomes (χ² = 25.746, p < 0.001), with substantially higher mortality among patients who developed complications.

Conclusion: The reported incidence of mechanical complications in this study (34.3%) is markedly higher than contemporary international benchmarks (<1% in the reperfusion era), potentially reflecting delayed hospital presentation, limited reperfusion access, and a high-risk case mix at a major tertiary referral center. No statistically significant sex-based difference in mechanical complication incidence was observed; however, this finding should be interpreted cautiously given the sample size and absence of multivariable adjustment. Mechanical complications were strongly associated with in-hospital mortality, underscoring their catastrophic clinical significance. These findings highlight the urgent need for early AMI recognition, rapid reperfusion therapy, routine echocardiographic surveillance, and strengthened cardiac surgical capacity at tertiary care centers in Pakistan. Future multicenter prospective studies with standardized diagnostic protocols and comprehensive reperfusion data are essential to validate these findings and inform healthcare policy.