Impact of Systemic Pulmonary Shunt for Tetralogy of Fallot on Pulmonary Valve Annulus Growth and Long-Term Pulmonary Valve Function

T. Hataoka¹, F. Shikata², T. Okamura³, N. Oka⁴, T. Tomoyasu⁵, M. Kaneko⁵, Y. Matsunaga¹, K. Matsui⁵, S. Horie⁶, K. Miyaji^6
1Gunma Children's Medical Center, Shibukawa, Gumma ²Kitasato University, Sagamihara City, KNG ³Gunma Children's Medical Center, Tokyo, Gumma ⁴Jichi Children's Medical Center Tochigi, Shimotsuke, Tochigi, Tochigi ⁵Jichi Children's Medical Center Tochigi, Shimotsuke, Tochigi ⁶Dept. of Cardivascular Surgery, Kitasato University School of Med, Sagamihara, Kanagawa

Purpose: This study aims to evaluate the growth of small pulmonary valve annulus (PVA) after systemic pulmonary shunt (SPS) in patients with tetralogy of Fallot (TOF) and to assess its impact on the long-term pulmonary valve function after intracardiac repair (ICR).

Methods: We conducted a retrospective review of 54 patients who underwent SPS out of 143 patients who received ICR for TOF at three institutions between 2005 and 2023. Valve-sparing repair (VSR) was considered when the PVA Z score was -3.0 or higher. We compared the VSR group (16 cases, 30%) with the transannular patch (TAP) group (38 cases, 70%) with the surgical outcomes. Right ventricular outflow tract stenosis (RVOTS) was defined as a pressure gradient of 50 mmHg or more, and pulmonary regurgitation (PR) was defined as moderate or worse, both assessed by echocardiography. Continuous variables were expressed as median and interquartile range.

Results: There were no surgical or long-term deaths. The median age at SPS was 44 days (20–101), and at ICR was 9.3 months (5.0–14.7). The follow-up period after ICR was 6.9 years (2.8–9.9). The PVA Z score significantly increased post-SPS in the VSR group (pre-SPS to pre-ICR: VSR group, -3.2 (-5.0–-2.6) to -1.9 (-3.4–-1.2); TAP group, -4.3 (-5.7–-2.7) to -3.1 (-4.9–-1.9), P=0.03). Ten years after ICR, the PR-free rate was significantly better in the VSR group (63% vs. 24%, P=0.009). The two groups had no significant differences in the RVOTS-free rate (84% vs. 93%, P=0.73) and the reintervention-free rate (65% vs. 65%, P=0.93). Multivariate analysis revealed that a pre-SPS PVA Z score (P=0.03) was a significant factor in achieving a PVA Z score of -3.0 or higher post-SPS, with a cut-off value of -4.1 (AUC: 0.76) determined by ROC analysis.

Conclusion: SPS for TOF promotes PVA growth, and long-term pulmonary valve function is favorable following VSR.

Identify the source of the funding for this research project: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.