The Impact of Bariatric Surgery on Cardiopulmonary Function: Analyzing VO₂ Recovery Kinetics

To assess cardiopulmonary capacity, autonomic heart function, and oxygen recovery kinetics during exercise testing before and after bariatric surgery.

This is a prospective cohort study. Symptom-limited cardiopulmonary exercise testing was performed with 24 patients, 1 week before and 4 months after bariatric surgery. The main variables were maximum oxygen uptake (VO₂ max), the time elapsed until the appearance of the first ventilatory threshold (TLV1), and VO₂ oxygen kinetics during recovery with a 50% reduction in peak oxygen uptake in the recovery period after exercise (50%VO₂RP).

The study demonstrated that the peak VO₂\kg increased significantly after bariatric surgery. When analyzed without adjusting for weight, the peak VO₂ paradoxically and significantly decreased after the surgical procedure (p = 0.007). The exercise time until the anaerobic threshold was longer after surgical procedure than before it (p = 0.001). Regarding post-exercise oxygen recovery kinetics, there was a faster reduction in the peak oxygen uptake after bariatric surgery than before the procedure (p < 0.001).

There was an obvious cardiac autonomic improvement after surgery. Despite the improvement in exercise tolerance, patients undergoing bariatric surgery had lower maximum oxygen consumption in the analysis not corrected for body weight. The mean VO₂RP before bariatric surgery was 141 s and was 111 s after the surgical procedure (p < 0.001). These results suggest an improvement in the recovery kinetics of oxygen consumption, a novel index of cardiac reserve capacity, on patients undergoing bariatric surgery.