Importance of pulmonary valve morphology for pulmonary valve preservation in tetralogy of Fallot surgery: comparison of the echocardiographic parameters

BACKGROUND: The decision to use transannular patching (TAP) during tetralogy of Fallot (TOF) repair depends on the pulmonary valve annulus size; the z score of the pulmonary annulus is the most commonly used predictor. However, definitive results are not obtained with z scores as different z score data sets are used for different parameters. PURPOSE: This study aimed to identify the echocardiographic and other key factors that warranted a change in the surgical method during TOF surgery. METHODS: Sixty-two patients were enrolled and divided into a pulmonary valve (PV) preservation group and a TAP group. Their medical records were reviewed. RESULTS: The z score for PV annulus (PVA), ratio of the PVA to aortic annulus size, and ratio of PVA to descending aorta (DAO) size were significantly different between the PV preservation and TAP groups (-1.72±1.52 vs. -3.07±1.94, P=0.004; 0.62±0.12 vs. 0.50±0.14, P=0.002; and 1.32±0.32 vs. 1.07±0.36, P= 0.008, respectively). For TAP repair, the PVA z score had a sensitivity of 65.4% and specificity of 73.1%, ratio of PVA to aortic annulus size had a sensitivity of 73.1% and specificity of 65.4%, and ratio of PVA to DAO size had a sensitivity of 69.2% and specificity of 57.7%. The TAP group showed more monocuspid PVs (P=0.011), while the PV preservation group showed more tricuspid PVs (P=0.027). Commissurotomy was more frequently performed in the PV preservation group than in the TAP group (P=0.001). Of patients with commissurotomy, 58% showed a PV z score<-2. CONCLUSION: Although various echocardiographic parameters may serve as predictors for determining surgical methods for TOF patients, the PV morphology and tissue characteristics should also be considered.