Relationship Between Aortic Root Enlargement and Pulmonary Blood Flow in Pulmonary Atresia With Major Aortopulmonary Collateral Arteries.

BACKGROUND

Patients with pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries (PA/VSD/MAPCAs) have markedly enlarged aortas compared with standard control subjects. Previous studies have suggested that aortic enlargement may be attributable to a combination of increased flow and intrinsic aortopathy. We hypothesized that aortic sizes in patients with PA/VSD/MAPCAs would correlate with the ratio of pulmonary to systemic blood flow (Qp/Qs) values.

METHODS

This was a retrospective review of 169 patients with PA/VSD/MAPCAs who underwent a surgical procedure. Echocardiographic studies were reviewed to assess aortic root size and z-scores. The Qp/Qs values were gleaned from preoperative cardiac catheterization. Patients were divided into 3 subgroups: single-stage complete repair, unifocalization and shunt, and aortopulmonary window.

RESULTS

Median age at surgery was 6.1 months for the single-stage complete repair group, 5.9 months for the unifocalization and shunt group, and 1.9 months for the aortopulmonary window group. Patients who underwent a single-stage complete repair had higher Qp/Qs values (1.78 vs 0.94, 0.93; P < .001), higher absolute aortic root measurements (1.95 cm vs 1.66, 1.52; P < .05), and higher aortic root z-scores (5.81 vs 1.10, 2.92; P < .01) compared with patients who underwent unifocalization and shunt procedure and aortopulmonary window procedures. However, within each subgroup there was no correlation between Qp/Qs and either aortic root size or aortic root z-scores.

CONCLUSIONS

The data demonstrate that there were 3 distinct anatomic and physiologic patterns for the 3 subgroups. Within each subgroup, no correlation was found between Qp/Qs and either aortic root size or z-score. These results suggest that incremental increases in flow do not result in additional increases in aortic size.