Value of pulmonary annulus index in predicting transannular patch in tetralogy of Fallot repair

OBJECTIVE

It is very important to accurately assess the transannular patch (TAP) in the surgical treatment of tetralogy of Fallot (TOF). The pulmonary annulus index (PAI; the actual pulmonary annulus diameter divided by the expected pulmonary annulus diameter), GA ratio (the ratio of pulmonary annulus and aortic annulus), PAAI (the ratio of pulmonary annulus cross-section and aortic annulus cross-section), and pulmonary annulus Z score (PA Z score) were compared. This study aimed to analyze and explore the application value of PAI in predicting the need for TAP in children undergoing TOF repair.

METHODS

In total, 130 patients who were diagnosed with TOF and underwent TOF repair in Beijing Anzhen Hospital affiliated to Capital Medical University from December 2018 to December 2019 were retrospectively studied. In total, 112 cases were included in this study and 18 cases were excluded, of which 16 cases were aged above 18 years and 2 cases suffered from Down syndrome. They were divided into TAP group and no TAP group; the values of the pulmonary annulus and aortic annulus were measured. GA ratio, PAI, PAAI, the pulmonary annulus Z score, and main pulmonary artery (MPA) Z score were calculated to perform statistical analysis.

RESULTS

A total of 112 patients were included in the study, aged 4-177 months, with an average of 22.87 ± 30.21 months; 66 males and 46 females; weighing 5.3-29 kg, with an average of 9.94 ± 4.08 kg; three cases died, one case died of sepsis caused by pulmonary infection, one case died of low cardiac output syndrome, and one case died of multiple organ failure. In total, 62 cases (55.8%) did not undergo TAP and 50 cases (44.2%) underwent TAP. The pulmonary annulus Z score, main pulmonary artery Z score, and PAI in the TAP group were smaller than those in the no TAP group (p < .05). Receiver operating curve (ROC) analysis showed that when the cut-off value of pulmonary annulus was -1.98, the area under the curve (AUC) was 0.88, the sensitivity was 80%, and the specificity was 71%; when the cut-off value of PAI was 0.53, AUC was 0.85, the sensitivity was 75%, and the specificity was 80%; when the cut-off value of GA ratio was 0.55, AUC was 0.85, the sensitivity was 76%, and the specificity was 80%. The area under the PAAI curve was 0.85, the sensitivity was 76%, and the specificity was 79%. When the pulmonary valve Z score, PAI, GA ratio, PAAI, and MPA Z score were all greater than the dividing value, TAP was avoided in more than 90% of children with TOF. When the pulmonary valve Z score, PAI, GA ratio, PAAI, and the main pulmonary artery Z score were all below the dividing value, more than 90% of children with TOF needed TAP.

CONCLUSION

The predictive effect of PAI as a simple and effective predictor of TAP in TOF radical operation is the same as that of pulmonary annulus Z score, and combining it with the main pulmonary artery Z score was the most accurate method of prediction.

Accuracy of a New Echocardiographic Index to Predict Need for Trans-annular Patch in Tetralogy of Fallot

The long-term outcome after repair of tetralogy of Fallot (TOF) is critically dependent pulmonary valve competence that is compromised by trans-annular patch (TAP). We compared a new echocardiographic index [pulmonary annulus index (PAI)] to conventional methods of predicting need for TAP in infants undergoing TOF repair. Consecutive infants undergoing TOF repair were prospectively studied. Pre-operative aortic and pulmonary annuli and main pulmonary artery (MPA) diameters were measured and z scores determined. PAI was a ratio of observed to expected pulmonary annulus (PA) diameter. TAP was based on intra-operative sizing by surgeons blinded to PAI values. Receiver operator curves (ROC) were generated for all PAI, MPA z scores and pulmonary annulus z scores. Of 84 infants (8.6 ± 2.6 months; 7.5 ± 1.3 kg), 36 needed TAP (43%). All the three indices viz. PAI, Pulmonary annulus and MPA z scores performed similarly in predicting need for TAP (ROC curves ~ 80%). Combining cut-offs of MPA z scores (> - 3.83) with either PAI (> 0.73) or PA z score (> - 1.83) predicted avoidance of TAP with ~ 90% accuracy. When both PAI and MPA z scores were below the cut-offs there was an 80% likelihood of TAP. Failure to predict TAP was associated with unicommisural pulmonary valves. PAI was equal to PA z scores in predicting need for TAP during repair of TOF. Combining either with MPA z scores was the most accurate method of prediction. Failure of prediction was mainly due to presence of a unicommissural pulmonary valve.