Physiological consequences of percutaneous pulmonary valve implantation: the different behaviour of volume- and pressure-overloaded ventricles

Aims To investigate the early clinical and physiological consequences of relieving chronic right ventricular (RV) volume overload with percutaneous pulmonary valve implantation (PPVI). Methods and results We selected 17 patients (age 21.2 ± 8.7 years), from a total of 125 who underwent PPVI, because they had important pulmonary regurgitation (PR) [regurgitant fraction > 25% on magnetic resonance (MR)] and an echocardiographic gradient < 50 mmHg across the RV outflow tract. Cardiopulmonary exercise testing, tissue Doppler and MR were performed before and within 3 months of PPVI. Following PPVI, PR (40.7 ± 7.3 to 4.1 ± 6.1%, P < 0.001) and RV end-diastolic volume fell (115.4 ± 33.1 to 98.9 ± 32.0 mL/m2, P = 0.001); effective RV stroke volume increased (34.3 ± 7.8 to 44.4 ± 9.3 mL/m2, P < 0.001). Left ventricular end-diastolic volume (66.6 ± 18.0 to 73.4 ± 16.5 mL/m2, P = 0.014), stroke volume (38.4 ± 11.1 to 46.4 ± 10.2 mL/m2, P = 0.001) and ejection fraction (57.8 ± 8.1 to 63.5 ± 5.2 mL/m2, P = 0.001) increased. Pulmonary artery diastolic pressure (8.9 ± 4.5 to 12.5 ± 5.2 mmHg, P = 0.041) and mitral E/Ea increased (from 9.0 ± 2.0 to 11.6 ± 3.1, P = 0.003). Patients felt better, but standard measures of exercise capacity were unchanged. Conclusion PPVI relieves PR and restores compensatory cardiac performance. The lack of improvement in exercise parameters suggests that, in contrast to pressure overload, the contractile reserve of chronically volume-overloaded myocardium is limited.