Exercise performance and ventilatory efficiency in patients with mild and moderate liver cirrhosis

1. The impact of ventilatory efficiency on reduced exercise capacity and recovery oxygen kinetics has not been addressed in cirrhotic patients. The aim of the present study was to investigate exercise performance and ventilatory efficiency in patients with mild and moderate liver cirrhosis (LC). 2. Nineteen male non-hypoxic patients with LC (age 51.3 +/- 9.1 years; body mass index (BMI) 25.6 +/- 3.6 kg/m(2)) classified by the Child-Pugh score as class A (n = 7) and class B (n = 12) and 19 age- and BMI-matched controls participated in the study. Subjects undertook maximal incremental exercise testing on a treadmill using the Bruce protocol. 3. Patients with LC showed a reduced diffusion capacity (D(L,CO)%) compared with controls (74.6 +/- 15.2 vs 95.6 +/- 12.9%, respectively; P < 0.001), but a comparable volume standardized diffusion coefficient (1.33 +/- 0.22 vs 1.45 +/- 0.18 mmol/min per kPa per L, respectively; P = 0.74). Patients with LC had a significantly lower exercise capacity compared with controls (VO(2 max) 23.8 +/- 3.8 vs 30.6 +/- 4.4 mL/min per kg, respectively; P < 0.001). Recovery oxygen kinetics were also impaired in LC patients compared with controls (104.6 +/- 19.3 vs 84.4 +/- 22.7 s, respectively; P = 0.012). The chronotropic index was significantly lower in the LC group compared with controls (0.67 +/- 0.19 vs 0.82 +/- 0.17, respectively; P = 0.030) and LC patients showed higher ventilatory equivalents (30.4 +/- 3.8 vs 26.3 +/- 2.3, respectively; P < 0.001) and lower oxygen uptake efficiency slope values (2187 +/- 445 vs 2745 +/- 473 mL/min per log(10)L, respectively; P < 0.001) compared with controls, which is indicative of decreased ventilatory efficiency. Patients with LC also had a higher standardized maximal exercise perception score (SMEPS) compared with controls (0.62 +/- 0.18 vs 0.46 +/- 0.15, respectively; P = 0.011). Moderate negative correlations were found between Child-Pugh score and VO(2 max)% (r = -0.496; P = 0.031). 4. In conclusion, patients with mild and moderate LC have reduced exercise capacity, which correlates with Child-Pugh score, as well as reduced chronotropic index and prolonged recovery oxygen uptake kinetics. The results suggest worsened ventilatory efficiency during exercise and cardiopulmonary reasons for the higher SMEPS in these patients.