Impact of residual pulmonary stenosis and right ventricular contractility on the prognosis after pulmonary valve replacement for pulmonary regurgitation in repaired tetralogy of Fallot patients

Y. Tominaga¹, S. Iwai¹, M. Taira², S. Tsumura³, S. Miyagawa^2
1Department of Pediatric Cardiac Surgery, National Cerebral and Cardiovascular Center, Suita, Osaka ²Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Suita, Osaka ³Department of Cardiovascular Surgery, Osaka Women’s and Children’s Hospital, Izumi, Osaka

Purpose: The impact of residual pulmonary stenosis (rPS) on the prognosis after pulmonary valve replacement in repaired tetralogy of Fallot patients with pulmonary regurgitation remains controversial. rPS assessment is partially dependent on RV contractility, complicating this issue. This study aimed to investigate the impact of rPS according to the RV contractility.

Methods: From 2003 to 2020, 153 patients underwent pulmonary valve replacement (PVR) late after tetralogy of Fallot (TOF) repair. This multi-center retrospective study included 116 patients after excluding 37 patients with severe PS or systolic RV pressure of more than 80 mmHg.
Regarding residual PS, the PSR group was defined as 25 to < 50 mmHg, and the PR group as < 25 mmHg. For RV ejection fraction (EF), the preserved RVEF (pEF) group was defined as ≥40%, and the reduced RVEF (rEF) group as < 40%. In each combination, patients were divided into four groups (PR-pEF48, PSR-pEF16, PR-rEF43, and PSR-rEF9).
One-way ANOVA and post hoc analysis were used to compare the parameters of each group. Postoperative adverse events incidence was evaluated, including cardiac death, prosthetic valve dysfunction, arrhythmia requiring treatment, and heart failure hospitalization. The association between adverse events and hemodynamic parameters was analyzed using Cox regression analysis.

Results: The median follow-up period was 7.2±3.7 (mean±SD) years. No cardiac-related deaths were observed. One patient had prosthetic valve dysfunction due to infective endocarditis. Thirty-one patients (27%) experienced adverse events, including 20 for atrial tachycardia, four pacemaker implantations for sinus node dysfunction or AV block, four hospitalizations for heart failure, and three for ventricular tachycardia.
The 5-year adverse event-free rate was highest in the PSR-pEF group and lowest in the PSR-rEF group (100% and 53%, Log-rank p< 0.001). The PSR-rEF group had a significantly lower adverse event-free rate than PR-pEF (53% vs. 71%, Log-rank p=0.037) and PR-rEF (53% vs. 77%, Log-rank p=0.027).
Multiple comparison tests showed PSR-rEF had the highest right ventricular end-diastolic pressure (RVEDP) among four groups (PR-pEF 7.4±2.9, PSR-pEF 8.3±3.3, PR-rEF 7.8±2.2, and PSR-rEF 12.3±2.2 mmHg). There was no significant difference in RV end-diastolic volume index (ANOVA p=0.20). RV end-systolic volume index (RVESVI) and age at PVR were significant in ANOVA, but there were no significant differences between the PSR-rEF group and the other groups.
Multivariable analysis, including RVEDVP, RVESVI, and age at PVR, revealed that only RVEDP was significantly associated with postoperative adverse events (hazard ratio 1.2 per 1mmHg, 95% confidence interval 1.0-1.3, p=0.021).

Conclusion: The cardiovascular adverse event-free rates were the highest in PSR with preserved RVEF group and the lowest in PSR with reduced RVEF group, who had the highest RVEDP among the four groups, which suggested the progression of both systolic dysfunction and diastolic dysfunction of RV. Reduced RVEF may mask the intrinsic degree of residual stenosis, delaying surgical timing and resulting in adverse RV remodeling. The association between the degree of rPS and RVEF may be better considered in deciding the cardiac catheterization and PVR timing in patients with moderate-severe PR.

Identify the source of the funding for this research project: none