Congenital heart disease
Pulmonary vascular disease in Down’s syndrome with complete atrioventricular septal defect

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Abstract

We sought to determine the predisposing factors of pulmonary vascular disease (PVD) in complete atrioventricular septal defect. Down’s syndrome is considered a risk factor for PVD, but the progression of PVD differs in each case. Morphometric analysis in autopsied hearts showed that Rastelli type A morphology had a narrower left ventricular outlet and a wider right ventricular outlet than did type C. In 81 consecutive patients with Down’s syndrome who underwent cardiac catheterization, we estimated the following variables: Rastelli subtypes, pulmonary vascular resistance, pulmonary-to-systemic flow ratio, patients’ age, and operative outcome. The hemodynamic variables in those <1 year old did not differ between the groups with type A and type C. However, all 5 patients with fatal pulmonary hypertension in early infancy had type A morphology. The lung histology revealed that 3 of these patients already had irreversible PVD. At ≥1 year old, those with type A showed a significantly higher pulmonary vascular resistance (p <0.001) and a lower pulmonary to systemic flow ratio (p <0.05) than did those <1 year old. In contrast, neither of these variables in the type C group differed between those ≥1 and <1 year old. Moreover, those with type A had a greater risk of being contraindicated for surgical repair (p <0.05). We suspect, therefore, that type A morphology is an independent risk factor for PVD in those with Down’s syndrome associated with this anomaly. This hemodynamic influence could become obvious once patients are ≥1 year old. It may also sometimes result in irreversible PVD even in early infancy.

Section snippets

Patients

We studied a total of 81 consecutive patients with Down’s syndrome and a complete atrioventricular septal defect, in which the pulmonary artery pressure was at or near systemic level, as evaluated by cardiac catheterization between January 1982 and September 1999 at the Sakakibara Heart Institute. Because inclusion of complicated anomalies would bias the statistical analysis, patients with aortic coarctation, left ventricular hypoplasia, or isomerism of the atrial appendages were excluded from

Results

Of the 81 patients, 43 (53%) had Rastelli type A and the remaining 38 (47%) had type C. No patient had type B morphology. As for the inferior bridging leaflet, 54 patients had an undivided morphology and 15 had a divided leaflet, but in the remaining 12 patients the precise morphology was not determined. There was a reverse correlation between the pulmonary vascular resistance and pulmonary to systemic flow ratio before the operation (r = −0.72, p <0.0001; Figure 1).

Discussion

Recent progress in the surgical techniques and perioperative care for those with complete atrioventricular septal defect has allowed us to perform corrective surgery in early infancy.8, 12, 13, 14 The first 6 months of life is considered to be the best time for definitive repair in view of the progression of PVD1, 2, 3, 4, 5 and atrioventricular valve regurgitation.13, 14 Patients with Down’s syndrome are also considered as having a higher risk for PVD,2, 3, 4, 5, 6 because they often

Acknowledgements

We thank Yoshio Obunai, MD, PhD, Japan Research Promotion Society for Cardiovascular Disease, and Teruaki Kawai and Kazuo Nitta, MD, PhD, the Mokichi Okada Association (MOA) Health Science Foundation, Tokyo, for their help with this study.

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This study was supported by research grants from the Japan Research Promotion Society for Cardiovascular Disease, Tokyo; and the Mokichi Okada Association (MOA) Health Science Foundation, Tokyo, Japan.

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