Functional Evaluation in Obese Patients Before and After Sleeve Gastrectomy.

ABSTRACT

BACKGROUND: Although sleeve gastrectomy (SG) has become an important treatment option in severe obesity, cardiorespiratory and muscle function after SG has not adequately been investigated. METHODS: This is an observational study in 26 obese patients (BMI 45.2 ± 5.8 kg/m2), comparing physical function before and after 6 months from SG. All available patients listed for SG were here included. Incremental cardiopulmonary exercise tests, standardized strength tests, and balance analysis were performed. RESULTS: The substantial weight loss (-33.4 ± 11.0 kg) after SG led to increased peak work capacity (metabolic equivalents, METs) and relative peak oxygen uptake (VO2peak/kg) (both p < 0.001). However, the absolute VO2peak, oxygen pulse (VO2/heart rate (HR)), and the oxygen uptake efficiency slope (OUES) significantly declined after SG (all p < 0.001). Furthermore, HR/VO2-slope significantly worsened after SG (p < 0.001), whereas the HR reserve and HR recovery improved (all p ≤ 0.01). Parameters of ventilatory efficiency were not affected by SG. The time-constant (Tau τ) of the fundamental component of VO2-kinetics, reflecting oxygen metabolism in skeletal muscles, was found to be significantly worsened after SG (p < 0.05). Finally, muscle strength and balance parameters were not much affected by SG. CONCLUSIONS: The ventilatory and cardiac function do not appear negatively affected by SG; thus, we hypothesize that the decrease in aerobic capacity could be due to alterations in peripheral muscles. This might in part be due to a loss of muscle mass, although our patients' muscle strength did not decrease. Pilot results from VO2-kinetics analysis seem to support the hypothesis of a deterioration of oxidative muscle metabolism after SG.