Cardiovascular evaluation and management of severely obese patients undergoing surgery: a science advisory from the American Heart Association.

Obesity is associated with comorbidities that may lead to disability and death. During the past 20 years, the number of individuals with a body mass index >30, 40, and 50 kg/m(2), respectively, has doubled, quadrupled, and quintupled in the United States. The risk of developing comorbid conditions rises with increasing body mass index. Possible cardiac symptoms such as exertional dyspnea and lower-extremity edema occur commonly and are nonspecific in obesity. The physical examination and electrocardiogram often underestimate cardiac dysfunction in obese patients. The risk of an adverse perioperative cardiac event in obese patients is related to the nature and severity of their underlying heart disease, associated comorbidities, and the type of surgery. Severe obesity has not been associated with increased mortality in patients undergoing cardiac surgery but has been associated with an increased length of hospital stay and with a greater likelihood of renal failure and prolonged assisted ventilation. Comorbidities that influence the preoperative cardiac risk assessment of severely obese patients include the presence of atherosclerotic cardiovascular disease, heart failure, systemic hypertension, pulmonary hypertension related to sleep apnea and hypoventilation, cardiac arrhythmias (primarily atrial fibrillation), and deep vein thrombosis. When preoperatively evaluating risk for surgery, the clinician should consider age, gender, cardiorespiratory fitness, electrolyte disorders, and heart failure as independent predictors for surgical morbidity and mortality. An obesity surgery mortality score for gastric bypass has also been proposed. Given the high prevalence of severely obese patients, this scientific advisory was developed to provide cardiologists, surgeons, anesthesiologists, and other healthcare professionals with recommendations for the preoperative cardiovascular evaluation, intraoperative and perioperative management, and postoperative cardiovascular care of this increasingly prevalent patient population.