Discussion
Since 1982[3], PBPV is a primary technique that has been extensively used for PVS treatment. Several studies have discussed the safety, effectiveness, feasibility, and practicality of this technique. We performed a retrospective review of all pediatric population definitively diagnosed with PVS, and all study participants underwent PBPV at our institution. This is one of the largest series to describe the outcomes of the pediatric population diagnosed with PVS after PBPV.
Several studies reported the immediate, short-, intermediate-, and long-term effectiveness and safety of PBPV in different centers[11,12]. A previous study conducted by Dian Hong et al.[13] reported a restenosis rate of 6.4% (10 of 158) and reintervention rate of 3.7% (6 of 158), and indicated that PBPV was the primary treatment as it was safe and minimally invasive. Recently, Hansen et al.[14]conducted a multicenter study with the longest follow-up duration of up to 25 years, in this study, 83% of the study patients (n = 207) had a significant decrease in PVS after undergoing initial PBPV, while 17% required repeat intervention.
The adverse reactions caused by chronic PR were unclear. In a previous study conducted by Merino‐Ingelmo et al.[15], which included 53 patients who underwent PBPV, the majority of patients did not experience PR before the procedure; however, none of the patients showed absence of PR at the end of the study. In a larger study, David M. Harrild et al.[16] showed that severe PR and mild RV dilation occurred after PBPV. In this study, 34% of patients had a PR fraction of >15%, and 40% had an RV end-diastolic volume z-score of ≥2. However, severe PR or RV dilation rarely occurred. In the latest multicenter research by Hansen et al.[14], which included a larger sample size (n = 248), 42% (n = 33) of them had ≥moderate PR. This study indicated that young age, low weight, higher baseline RV-PA PSEG, increased baseline RV/systemic pressure ratio, and critical PVS were the risk factors for higher PR.
Our research showed that 76 (39.4%) of the follow-up patients had ≥moderate PR. In the multivariate analysis, lower weight and higher initial RV-PA PSEG were independent risk factors for ≥moderate PR. Although the degree of PR was increasing, it was well tolerated, and none of our study patients underwent pulmonary valve replacement for severe PR.
Several studies have been conducted to determine the target BAR. In previous studies, the finding that significant PR was uncommon in patients with a BAR of <1.4 support the appropriateness of 1.2 to 1.4 as a target BAR range. In a study by David M. Harrild et al.[16], patients with a smaller pulmonary valve z-score were more likely treated with a larger BAR. However, the results showed that using a BAR of >1.4 was more likely to cause severe PR. Sagar J. Pathak et al.[17] suggested that using a BAR of <1.2 significantly decreased the PR rate than a BAR of >1.2 without affecting the procedure efficacy and increasing the need for repeat intervention for residual PVS. A latest study by Dian Hong et al.[13] showed that the choice of BAR could affect the immediate therapeutic effects and medium‑term follow-up results. The BAR they selected was 1.2–1.4, which was widely accepted and has already been widely recommended in some guidelines. Our study showed that BAR was not a risk factor for ≥moderate PR.
Some limitations exist in the present study. This study had a short follow-up duration, was retrospective in nature, and was conducted at a single center. This study had a relatively short follow-up period after initial PBPV, and the maximum follow-up time was no more than 9 years. The participants were from a single center rather than a multicenter, and a data bias may exist. Due to the retrospective cohort design of this study, the collection of clinical data was inadequate. Notwithstanding, this research can still be used as a reference for future studies. Therefore, with these limitations, a more comprehensive assessment is required for future work.