Ventricular remodelling after pulmonary valve replacement: Comparison between pressure-loaded and volume-loaded right ventricles

OBJECTIVES: In patients with severe pulmonary valve regurgitation or stenosis, pulmonary valve replacement (PVR) has a favourable effect on right ventricular (RV) volume and pressure unloading. PVR thereby decreases the progression of RV dilatation and/or hypertrophy. This study investigates RV remodelling patterns after PVR in patients with either pressure, volume or combined volume- and pressure-loaded RVs.

METHODS: We evaluated 79 consecutive patients who had undergone PVR, between 1999 and 2012 beyond the age of 14 years. Comparisons were made according to the RV loading condition, i.e. isolated volume-loaded (iPR, n = 53), combined volume- and pressure-loaded (cPR/[PS] pulmonary stenosis, n = 16), and isolated pressure-loaded RVs (iPS n = 10). The main study outcome was the change of the RV end-diastolic diameter (Delta RVEDD) before and after PVR, measured on echocardiography.

RESULTS: The majority of patients (65%) had a tetralogy of Fallot. After PVR, the RVEDD decreased with 5.3 mm/m(2), body surface area (BSA) (P <0.001). In addition, the RV end-diastolic volume on cardiac magnetic resonance declines with 40 ml/m(2), BSA (P <0.001). The change in the RVEDD after PVR was different according to the loading condition (i.e. iPR: -6.6, cPR/PS: -4.7 and iPS: +0.4 mm/m(2), P <0.001). In a multivariate regression model, pressure load remained a significant predictor of decreased RVEDD (P = 0.005).

CONCLUSIONS: The current data indicate that the type of right ventricular loading (pressure versus volume) before PVR affects the RV remodelling pattern after PVR. Right ventricular pressure load has an adverse effect on early RV remodelling after PVR.