Cardiac procedures in patients with a body mass index exceeding 45: outcomes and long-term results

Obesity has become a public health crisis. Although prior studies in obese patients undergoing cardiac surgical procedures have shown variable effects on outcomes, data are limited for extremely obese patients (body mass index [BMI] > or = 45). We undertook this study to evaluate outcomes in this cohort.

A retrospective analysis was performed on 14,571 patients in our database who underwent cardiac operations from 1992 to 2005. Patient demographics, comorbidities, and outcomes were recorded. A univariate analysis between two groups: BMI 21 to 34.9 and BMI 45 or more was performed. Logistic regression models were used to identify independent risk factors for 30-day mortality. Long-term follow-up of the extreme obese group was achieved.

We identified 128 extreme obese patients, and 480 patients with a BMI of 21.0 to 34.9 were randomly selected for comparison. Univariate analysis showed significant differences in age, gender, and multiple comorbidities, as well as in cardiopulmonary bypass and cross-clamp times, operative procedure, and transfusion requirements. Extreme obese patients had a higher incidence of infection, acute renal failure, and 30-day mortality. Logistic regression analysis showed BMI, preoperative renal insufficiency, and transfusion status to be independent risk factors for 30-day mortality. Follow-up data did not reveal significant functional improvements. Long-term survival was 33.6% at 12 years.

Extreme obese patients undergoing cardiac surgical procedures have higher perioperative morbidity and mortality compared with a lower BMI group. BMI and preoperative renal insufficiency increase mortality in both groups, whereas transfusion does so only in the extreme obese. These patients can realize acceptable outcomes from cardiac procedures, but continue to suffer from the comorbidities of obesity.