Background: Despite excellent survival following Tetralogy of Fallot repair, residual right ventricular (RV) outflow tract dysfunction often persists. Pulmonary valve replacement (PVR) is commonly performed, yet its efficacy to improve cardiac parameters with time remains unclear. We performed a meta-regression to summarize the known impact of PVR on key cardiac outcomes over time.
METHODS AND RESULTS: Relevant articles reporting on at least one outcome of pulmonary regurgitation, left and RV volumes, QRS length, RV ejection fraction, VO2max, NYHA status in patients with TOF before and after PVR were retrieved. A multilevel random-effects meta-regression was conducted using time since PVR as a covariate. Local regression smoothing was used for visual exploration of outcome trajectories over time.
Seventy-six studies met the inclusion criteria. Compared to pre-PVR values, PVR was associated with absolute reductions in RV end-systolic volume (–32.5 mL/m2, 95% confidence interval (CI): –37.4 mL/m2 to –27.7 mL/m2) and end-diastolic volume (–59.6 mL/m2, 95% CI: –67.2 mL/m2 to –52.0 mL/m2) and with small increase of left ventricular end-diastolic volume (4.6 mL/m2, 95% CI 2.2 mL/m2 to 7.0 mL/m2). NYHA functional class was also immediately improved (–0.78 class, 95% CI –1.18 to –0.37). PVR had no immediate significant effect on left ventricular systolic volume, peak VO2, RV ejection fraction or QRS duration. Median follow-up time was only 12.7 months (IQR 7.3-26.0), and only 2 studies had median follow-up time longer than 5 years. The estimated change for each year after PVR for RV end-systolic volume was minimal: –0.4464 mL/m2 (see Figure 1a; 95% CI –0.9360 mL/m2 to 0.0432 mL/m2). The annual change for RV end-diastolic volume was also minimal: –0.0504 mL/m2 (see Figure 1b; 95% CI –0.7416 mL/m2 to 0.6408 mL/m2). There was limited statistical power for medium or long-term inference, and the effect of time was not statistically significant for any of the parameter. However, visual inspection of the regression curves suggested a plateau or a possible slight increase in RV volumes between 30 and 60 months.
Conclusion: The long-term impact of PVR remains uncertain. Despite many short-term post PVR studies, there was insufficient long-term data or volume trends to draw firm conclusions. Further research is needed.
