Does patch closure of subarterial ventricular septal defect affect the growth of pulmonary valve?

Patch closure of the subarterial ventricular septal defect requires suture placement at the pulmonary annulus. We aimed to identify whether patch closure of subarterial ventricular septal defect would affect the growth of pulmonary annulus in comparison with that of perimembranous ventricular septal defect.

Of 361 patients who underwent patch closure of ventricular septal defect from January 1992 to December 1999, 98 (51 subarterial, 47 perimembranous) had echocardiographic data available for measurement of both preoperative and postoperative (more than 5 years after operation) pulmonary and aortic annular diameters. The pulmonary/aortic annular diameter ratio and their growth rates in the subarterial group were compared with those in the perimembranous group. The perioperative variables correlated with the pulmonary annular growth in subarterial group were also identified.

The mean follow-up duration was 7.2 years. Preoperative pulmonary/aortic annular diameter ratio was 1.45 (range, 0.94-2.31) in the subarterial group and 1.57 (range, 1.15-2.51) in the perimembranous group (p=0.059). The latest postoperative ratio was significantly lower in the subarterial group [subarterial: 1.02 (range, 0.77-1.41) vs perimembranous: 1.36 (range, 1.11-1.75), p<0.01]. Twenty-three patients (45%) in the subarterial group had the ratio less than 1. The pulmonary annular growth rate in the subarterial group was lower than that in the perimembranous group (subarterial: 0.34 mm/year, perimembranous: 1.03 mm/year, p<0.01). Preoperative pulmonary/aortic annular diameter ratio (r=0.885, p<0.01), age at operation (r=-0417, p<0.01), weight at operation (r=-0.357, p<0.05), and ventricular septal defect size (r=0.298, p<0.05) were found to have correlation with pulmonary annular growth in the subarterial group.

Our data show that pulmonary annular growth after patch repair of subarterial ventricular septal defect is suboptimal compared with perimembranous ventricular septal defect. Careful attention must be paid to the possible late clinical implication caused by impaired pulmonary annular growth after patch repair of subarterial ventricular septal defect.