Comparing Cardiopulmonary Exercise Testing in End-Stage Liver Disease Patients

Poor cardiopulmonary fitness has been associated with worse outcomes in liver transplant candidates. Purpose To determine if a modified 3-minute step test (potentially office based) is feasible and equivalent to standard cardiopulmonary exercise testing (CPET) in liver transplant candidates with severe decompensation. Methods Five patients with Childs-Pugh C end-stage liver disease and severe debility awaiting liver transplantation performed both standard CPET and the modified 3-minute step test (Shape medical systems). Results All 5 patients were able to complete both tests. Mean age was 59.8 ± 9 years, mean MELD score was 20 (range 13-26), and mean BMI was 27.6 kg/m² (range 16.4-37.2). Peak Vo₂ was similar with a mean of 901 mL/min (step test) compared to 856 mL/min (cycle test), P =.64. Vo₂ at a respiratory exchange ratio (RER) of 1.0 was similar with both tests (681 mL/min (step) vs 646 mL/min (cycle), P =.69. Ve/Vco₂ slope (ventilatory efficiency) was similar (40 vs 39, P =.94). The ventilatory compensation point (i.e. anaerobic threshold) was also similar (∼80% of peak Vo₂) for both studies. Conclusion The modified 3-minute step test provides a simplified, potentially office-based assessment of cardiopulmonary exercise capacity and gas exchange measures as standard testing in patients with decompensated end-stage liver disease, with similar tolerability.