Does Body Mass Index Affect Mortality in Coronary Surgery?

Area of Science:

• Cardiology
• Surgical Outcomes
• Nutritional Science

Background:

• Body Mass Index (BMI) is a key indicator of nutritional status, classifying individuals into weight categories.
• Obesity (BMI > 30 kg/m²), defined as excessive fat accumulation, is recognized as a complicating factor in anesthesia and surgery.
• Obesity is a known risk factor for complications such as mediastinitis following coronary artery bypass grafting (CABG).

Purpose of the Study:

• To investigate the association between Body Mass Index (BMI) categories and operative mortality in patients undergoing coronary artery bypass grafting (CABG).
• To evaluate the impact of underweight, normal weight, overweight, and varying degrees of obesity on CABG outcomes.

Main Methods:

• A literature review was conducted on studies reporting CABG mortality stratified by BMI groups.
• BMI categories included: Underweight (≤18.49 kg/m²), normal weight (18.5-24.9 kg/m²), overweight (25.0-29.9 kg/m²), mild obesity (30.0-34.9 kg/m²), moderate obesity (35.0-39.9 kg/m²), and morbid obesity (≥40.0 kg/m²).

Main Results:

• Eighteen studies encompassing 1,027,711 patients were analyzed.
• The overall cumulative mortality for CABG was 2.7%.
• Underweight patients exhibited the highest mortality rate (6.6%), followed by morbidly obese patients (3.44%). Overweight patients had the lowest mortality (2.1%).

Conclusions:

• Extreme BMI values, both underweight and morbidly obese, are associated with increased crude mortality after CABG.
• Under-nutrition and morbid obesity warrant further investigation as significant risk factors in coronary surgery.
• Nutritional status is a critical factor influencing outcomes in patients undergoing CABG.