Impact of percutaneous pulmonary valve implantation for right ventricular outflow tract dysfunction on exercise recovery kinetics

Abstract

The recovery of cardiopulmonary variables from peak exercise in patients with pulmonary stenosis (PS) or regurgitation (PR) is delayed, but the impact of treating PS or PR on exercise recovery kinetics is unknown. 43 patients (median age 14 years) with PS (n = 23) or PR (n = 20) after repair of congenital heart disease underwent successful percutaneous pulmonary valve implantation (PPVI). Cardiopulmonary exercise tests (CPET) were performed both before and within 1 month after PPVI. Apart from peak oxygen uptake (VO2), the constant decay of VO2, CO2 output (VCO2), minute ventilation (VE), and heart rate (HR) and oxygen pulse were calculated for the first minute of recovery as the first-degree slope of a single linear relation. PPVI led to a significant improvement in NYHA functional class in the PS and PR groups (p<0.001 and p=0.0015, respectively). On CPET, peak VO2 improved post-PPVI only in the PS (25.6 ± 6.2 vs. 27.8 ± 7.9 ml/kg/min; p = 0.01) but not PR group (29.0 ± 9.8 vs. 28.6 ± 8.9 ml/kg/min; p = 0.6). However, VO2 slope improved in the PS (0.40 ± 0.23 vs. 0.65 ± 0.27, p < 0.001) as well as in the PR group (0.56 ± 0.37 vs. 0.67 ± 0.37, p = 0.003) as did VCO2 slope (0.39 ± 0.2 vs. 0.55 ± 0.24, p = 0.002 and 0.42 ± 0.33 vs. 0.53 ± 0.35, p = 0.02: for the PS and PR groups, respectively). The VE and HR slopes did not change after PPVI. Despite the lack of improvement in exercise capacity in the PR group, treatment of PS and PR by PPVI induces significant and similar improvements in the ability of recovering from maximal exercise in the 2 groups.

Keywords: Congenital; Exercise test; Melody; Pulmonary regurgitation; Pulmonary stenosis; Right ventricular outflow tract.