Optimal Z-Score Use in Surgical Decision-Making in Pulmonary Atresia With Intact Ventricular Septum

In the surgical treatment of pulmonary atresia with intact ventricular septum, the size of the tricuspid valve annulus (as measured by z-scores) has emerged as a significant factor in deciding which repair to perform. Various tricuspid valve annulus z-scores are reported as "cutoffs" for successful biventricular repair. We aimed to determine whether the use of different z-score data sets contributed to the gross variation in "cutoffs" for successful biventricular repair reported in the literature.

A single search was made of PubMed using the "advanced" setting with the following search terms: pulmonary, atresia, intact, septum, z, and score. The filters "title" and "title/abstract" were used for the first four and last two terms, respectively; the instruction "AND" combined all terms. Articles that identified which z-score data set was used in patients with biventricular repairs were included.

From 13 articles, 1,392 patients were studied, 410 (29.5%) of which achieved biventricular repair. Three z-score data sets were quoted; mean tricuspid valve annulus z-scores in biventricular repair patients ranged between -0.53 and -5.1. After correcting for discrepancies between z-score data sets, no study reported a mean tricuspid valve annulus z-score <-2.8 in biventricular repair patients and 83.3% reported mean tricuspid valve annuli z-scores >-1.7.

The use of varied tricuspid valve annuli z-score data sets may have contributed to gross variations in reported "cutoffs" for successful biventricular repair. This could lead to inappropriate surgical pathway allocation.