Objective: To investigate whether weight loss after bariatric surgery (gastric bypass) is associated with changes in aortic function (an important determinant of left ventricular function) and in left ventricular function, in morbidly obese individuals 3 and 36 months after surgery.
Methods: We used echocardiography to evaluate 60 obese individuals [body mass index (BMI) > 40 kg/m2] who underwent surgery and 20 obese individuals who neither underwent surgery nor lost weight, at baseline and at 3 and 36 months of follow-up, and 40 lean individuals (BMI < 25 kg/m2) of similar age, sex and risk factors, at baseline. We measured aortic strain, distensibility, stiffness index, pressure-strain modulus and Doppler indices of left ventricular diastolic dysfunction (ratio of peak early to peak atrial flow velocities, isovolumic relaxation time and deceleration time).
Results: Baseline aortic function and Doppler diastolic indices were impaired in obese individuals compared with those who were lean (P < 0.05). During 3 and 36 months of follow-up, BMI and left ventricular diastolic diameter, volume, mass and wall thickness were reduced, and indices of aortic function and left ventricular diastolic function were normalized, in obese individuals after surgery [aortic distensibility (cm2 x dyn(-1) x 10(-6)): 1.9 before surgery, 3.4 at 3 months after surgery and 4.3 at 3 years after surgery, compared with 3.36 in lean controls; P < 0.01], but not in those who did not lose weight. The reduction in BMI after surgery was related to the concomitant improvement in indices of aortic function (P < 0.01) and isovolumic relaxation time (P < 0.05) after adjustment for age, sex and concomitant reduction in blood pressure, lipids and glucose concentrations.
Conclusion: Weight reduction after bariatric surgery normalizes aortic function, reduces left ventricular hypertrophy and, thus, improves left ventricular diastolic function in morbidly obese individuals over a 3-year period of follow-up.