Challenges in cardiac risk assessment in bariatric surgery patients.

Bariatric surgery has serious associated medical comorbidity and procedure-related risks and is thus considered an intermediate- to high-risk noncardiac surgery. Most patients referred for bariatric surgery have a low or very low functional capacity, making cardiac risk assessment imperative. Stress echocardiography has a high negative predictive value and can avoid some of the table weight and torso diameter problems associated with myocardial perfusion imaging. Echocardiograph contrast agents improve the ability to identify endocardial borders and assess ventricular wall motion and may be used with stress and nonstress imaging protocols. Single photon emission computer tomography (SPECT) imaging with attenuation correction, combined supine and prone imaging, use of technetium isotope, and positron emission tomography (PET) imaging may all provide some advantage for myocardial perfusion imaging for the obese patient.