Causes Of Exercise Intolerance And Their Role In Predicting Response To Prehabilitation In Patients Awaiting Major Digestive Surgery

PURPOSE: To explore potential causes leading to exercise intolerance in patients awaiting major digestive surgery and their role as predictive factors in responding to a preoperative exercise training program. METHODS: we retrospectively reviewed patients participating in an exercise-based prehabilitation program in whom an incremental and a steady-state cardiopulmonary exercise test (CPET) was performed at baseline and pre-surgery (n = 49, mean age 69.8 years old, 67.3% male). Causes for exercise intolerance (VO2peak < 80% of predicted) were analyzed according to available literature. Response to preoperative exercise was measured with a steady-state CPET and factors associated with a positive response (>30% increase in endurance time) were identified. RESULTS: main parameters from the incremental CPET are shown in Table 1. A total of 31 patients (63%) were classified as having exercise intolerance. Of those, 19 patients (61%) reached >85% of their predicted maximal voluntary ventilation, suggesting a ventilatory limitation. Oxygen pulse (VO2/FC) at VO2peak was decreased in 22 (71%) patients which according to the literature suggests a cardiovascular impairment related to a limitation in systolic volume. Anaerobic threshold was identified in 37 (75%) patients and was lower than 40% of VO2max in 66.7% of them. In terms of exercise response, 38 (77%) patients increased their endurance time > 30% after prehabilitation. Those who responded to exercise training achieved greater leg fatigue (5.2 vs. 3.4) during incremental CPET and had a normal VO2AT compared to non-responders (46% vs. 26.4% of VO2max). No other differences or factors were identified. CONCLUSIONS: exercise intolerance appears frequent in surgical candidates. In this cohort, response to preoperative exercise training seems to be influenced mostly by peripheral and/or cardiometabolic dysfunctions. - Results of incremental CPET at baseline (n = 49) VO2peak (mL/min) 1069 (498) VO2peak %predicted 72.4 (20.2) VO2peak (ml/kg/min) 16 (13) Watts peak 79.4 (43.4) Watts peak %predicted 64.8 (23.7) VE peak (litres) 53.9 (22.5) VE peak %predicted 106 (31) FC peak (bpm) 124 (22.8) FC peak %predicted 82 (14.7) RQ peak 1.35 (0.1) O2pulse (VO2/FC) peak 8.7 (3.9) O2 pulse peak %predicted 68.5 (23.9) VO2AT (mL/min) 724 (310) VO2_AT (percentage of VO2max) 45.5 (17.6) FIS PI00425