Severely obese patients need careful pre-op evaluation

Clinicians face a challenge in accurately identifying severely obese patients who are at greatest risk of cardiovascular complications before, during and after surgery, according to a new advisory statement from the American Heart Association. “The physical examination and ECG often underestimate cardiac dysfunction in obese patients,” it said. “The risk of an adverse perioperative cardiac event...is related to the nature and severity of their underlying heart disease, associated comorbidities, and the type of surgery.” Relevant obesity-related comorbidities included atherosclerotic cardiovascular disease, heart failure, systemic hypertension, and pulmonary hypertension related to sleep apnoea and obesity hypoventilation. Other common problems included cardiac arrhythmias, deep vein thrombosis, a history of pulmonary embolism, and poor exercise capacity. Obesity was also associated with cardiomyopathy, in which changes in haemodynamics altered left ventricular structure and function, and ultimately caused heart failure. Severe obesity had not been associated with increased mortality in patients having cardiac surgery, but they were more likely to have a longer hospital stay, need prolonged assisted ventilation or experience renal failure. Factors predicting increased mortality included a BMI of 50 kg/m2 or more, being male or older than 45, and having comorbid hypertension or a history of pulmonary embolism. Circulation 2009; 120: published online....