Influence of obesity on microvascular obstruction and the myocardial area at risk in patients with ST-segment elevation myocardial infarction.

Objective: To explore the influence of obesity on microvascular obstruction (MVO) and myocardial area at risk (AAR) in patients with ST-segment elevation myocardial infarction (STEMI).

Methods: A retrospective analysis was performed on patients with first-episode STEMI hospitalized at Nanjing University of Traditional Chinese Medicine between May 2020 and May 2022. Patients were categorized into normal weight, overweight, and obese groups based on their body mass index (BMI). Baseline characteristics, blood biochemical indexes and cardiac magnetic resonance (CMR) parameters were compared among the groups. Pearson correlation analysis and binary logistic regression were performed to assess the correlation between MVO ratio and BMI in each subgroup and to identify the risk factors for MVO.

Results: Of the 233 patients, 77 were of normal weight, 102 were overweight, and 54 were obese. Obese patients were younger than normal-weight and overweight patients. Both the obese and overweight groups had significantly higher rates of hypertension and hyperlipidemia compared to the normal-weight group. Hemoglobin (Hb), triglycerides (TAG), and high-density lipoprotein cholesterol (HDL-C) levels were higher in obese patients, while creatine kinase isoenzyme (CK-MB) levels were lower (all P<0.05). MVO ratio showed a negative correlation with BMI across all patients (r=-0.133, P<0.05). Binary logistic regression confirmed that BMI was an independent predictor of MVO [0.908 (0.838-0.984), P=0.019]. Additionally, the AAR ratio was significantly lower in obese patients compared to those of normal weight.

Conclusions: Overweight and obese patients are strongly associated with a reduced risk of MVO, and BMI is an independent predictor of MVO. Obesity is significantly linked to a smaller AAR in myocardial infarction.