A Novel Predictive Value for the Transannular Patch Enlargement in Repair of Tetralogy of Fallot.

BACKGROUND

In tetralogy of Fallot, whether relieving right ventricular outflow tract obstruction requires transannular patch enlargement (TAPE) of the pulmonary valve depends on pulmonary valvular annulus size. The z-score of pulmonary annulus is most commonly used as a predictor of the need for TAPE. However, the z-score is a complex value affected by height, body weight, body surface area, and different reference populations. Therefore, we hypothesized that the great artery annulus size ratio (pulmonary valvular annulus size to aortic valve annuls size [GA ratio]) may be a better predictor of the need for TAPE.

METHODS

We analyzed 122 patients retrospectively who had undergone total correction of tetralogy of Fallot between January 2007 and March 2015. We categorized the patients into two groups, TAPE versus non-TAPE. Great arterial annuli sizes were evaluated in each group, and the GA ratio cutoff values for TAPE were calculated.

RESULTS

In total, 40 patients (32.8%) required TAPE. Both GA ratios and z-scores were smaller in the TAPE group than in the non-TAPE group (0.51 versus 0.67, p < 0.0001, and -2.46 versus -0.85, p < 0.0001, respectively). In receiver operating characteristics analyses, the z-score and GA ratio cutoff values were -1.67 (area under the curve = 0.797) and 0.56 (area under the curve = 0.900), respectively, demonstrating that the GA ratio was a more powerful diagnostic tool as a predictor of TAPE (p = 0.014).

CONCLUSIONS

Our results suggest that the GA ratio is a useful predictor for TAPE and can be applied readily and simply in clinical practice.