BMI, Infarct Size, and Clinical Outcomes Following Primary PCI: Patient-Level Analysis From 6 Randomized Trials

The aim of this study was to examine the association between body mass index (BMI), infarct size (IS) and clinical outcomes.

The association between obesity, IS, and prognosis in patients undergoing primary percutaneous coronary intervention (pPCI) for ST-segment elevation myocardial infarction is incompletely understood.

An individual patient-data pooled analysis was performed from 6 randomized trials of patients undergoing pPCI for ST-segment elevation myocardial infarction in which IS (percentage left ventricular mass) was assessed within 1 month (median 4 days) after randomization using either cardiac magnetic resonance (5 studies) or ^99mTc sestamibi single-photon emission computed tomography (1 study). Patients were classified as normal weight (BMI <25 kg/m²), overweight (25 kg/m² ≤BMI <30 kg/m²), or obese (BMI ≥30 kg/m²). The multivariable models were adjusted for age, sex, hypertension, hyperlipidemia, current smoking, left main or left anterior descending coronary artery infarct, baseline TIMI (Thrombolysis In Myocardial Infarction) flow grade 0 or 1, prior myocardial infarction, symptom-to-first device time, and study.

Among 2,238 patients undergoing pPCI, 644 (29%) were normal weight, 1,008 (45%) were overweight, and 586 (26%) were obese. BMI was not significantly associated with IS, microvascular obstruction, or left ventricular ejection fraction in adjusted or unadjusted analysis. BMI was also not associated with the 1-year composite risk for death or heart failure hospitalization (adjusted hazard ratio: 1.21 [95% confidence interval: 0.74 to 1.71] for overweight vs. normal [p = 0.59]; adjusted hazard ratio: 1.21 [95% confidence interval 0.74 to 1.97] for obese vs. normal [p = 0.45]) or for death or heart failure hospitalization separately. Results were consistent when BMI was modeled as a continuous variable.

In this individual patient-data pooled analysis of 2,238 patients undergoing pPCI for ST-segment elevation myocardial infarction, BMI was not associated with IS, microvascular obstruction, left ventricular ejection fraction, or 1-year rates of death or heart failure hospitalization.