Preoperative thresholds for mid-to-late haemodynamic and clinical outcomes after pulmonary valve replacement in tetralogy of Fallot

Abstract

Aims: The right ventricle (RV) remodels early after pulmonary valve replacement (PVR) in tetralogy of Fallot (TOF) patients. Previously reported preoperative thresholds to achieve early postoperative RV normalization were consistently close to 80 mL/m(2) for end-systolic volume (ESV) and 160 mL/m(2) for end-diastolic volume (EDV). Our objective was to determine whether these thresholds were also associated with mid-to-late RV normalization and clinical events.

Methods and results: Out of a multicentre cohort of 157 TOF patients who had undergone PVR, in 65 patients (62% male, age 29 ± 8 years, homograft in 98%) cardiovascular magnetic resonance (CMR) imaging was performed preoperatively and >3 years (6.3 years, interquartile range: 4.9-9.5) postoperatively. Mid-to-late haemodynamic outcome was classified as: 'RV normalization' [RV ejection fraction (EF) > 48% and RV EDV < 108 mL/m(2)] in 14 of 65 (22%) patients, 'intermediate' in 34 of 65 (52%) patients, and 'suboptimal' (RV EF < 45% and RV EDV > 120 mL/m(2)) in 17 of 65 (26%) patients. Preoperative RV ESV < 80 mL/m(2) was strongly associated with favourable mid-to-late haemodynamic outcome in a proportional odds model [common odds ratio (OR): 0.04 for worse class, 95% confidence interval (CI): 0.01-0.17]. During 7.8 ± 4.0 years follow-up after PVR, adverse clinical events (death, sustained ventricular tachycardia, or heart failure) occurred in 18 of 106 (17%) patients with preoperative CMR available. Patients with preoperative RV ESV > 95 mL/m(2) were at increased risk for unfavourable mid-to-late haemodynamic outcome (common OR: 25.5, 95% CI: 5.35-122) and events (hazard ratio: 2.89, 95% CI: 1.03-8.11).

Conclusion: In TOF patients who had undergone PVR, the best preoperative threshold to achieve mid-to-late RV normalization was RV ESV < 80 mL/m(2). Patients with preoperative RV ESV > 95 mL/m(2) were at increased risk for suboptimal haemodynamic outcome and adverse clinical events. Our findings may assist in timing of PVR.

Keywords: Cardiovascular magnetic resonance imaging; Congenital heart disease; Pulmonary regurgitation; Pulmonary valve replacement; Tetralogy of Fallot.