This study sought to examine the prevalence and predictors of pulmonary regurgitation (PR) following balloon dilation (BD) for pulmonary stenosis (PS) and to investigate its impact on ventricular volume and function, and exercise tolerance.

Balloon pulmonary valvuloplasty relieves PS but can cause late PR. The sequelae of isolated PR are not well understood.

Patients were at least 7 years of age and 5 years removed from BD, and had no other form of congenital heart disease or significant residual PS. Cardiac magnetic resonance imaging and exercise testing were performed prospectively to quantify PR fraction, ventricular volumes and function, and exercise capacity.

Forty-one patients underwent testing a median of 13.1 years after BD. The median PR fraction was 10%; 14 patients (34%) had PR fraction >15%; 7 (17%) had PR >30%. PR fraction was associated with age at dilation (ln-transformed, R = −0.47, p = 0.002) and balloon:annulus ratio (R = 0.57, p < 0.001). The mean right ventricular (RV) end-diastolic volume z-score was 1.8 ± 1.9; RV dilation (z-score ≥2) was present in 14/35 patients (40%). PR fraction correlated closely with indexed RV end-diastolic volume (R = 0.79, p < 0.001) and modestly with RV ejection fraction (R = 0.50, p < 0.001). Overall, peak oxygen consumption (Vo₂) (% predicted) was below average (92 ± 17%, p = 0.006). Patients with PR fraction >15% had significantly lower peak Vo₂ than those with less PR (85 ± 17% vs. 96 ± 16%, p = 0.03).

Mild PR and RV dilation are common in the long term following BD. A PR fraction >15% is associated with lower peak Vo₂, suggesting that isolated PR and consequent RV dilation are related to impaired exercise cardiopulmonary function.