Tetralogy of Fallot: A Possible Etiology for Narrowing of the Right Pulmonary Artery

Abstract

Patients with tetralogy of Fallot have right ventricular outflow and pulmonary valve stenosis. They may also have more distal peripheral pulmonary artery stenoses. Peripheral stenosis is believed to be part of the spectrum of the genetic manifestation of tetralogy. Our hypothesis was that narrowing of the right pulmonary artery may be due to compression from the adjacent dilated ascending aorta. We identified 27 patients with tetralogy of Fallot who underwent magnetic resonance imaging scanning postoperatively, most often for evaluation of pulmonary valve stenosis and regurgitation. On the axial image at the level of the right pulmonary artery, we measured the transverse diameters of the ascending and descending aorta, and the minimum and maximum right pulmonary artery diameters. There was a significant correlation between the ratios of the ascending:descending aorta diameters and the maximum:minimum right pulmonary artery diameters. Thus, increasing ascending aorta size is associated with decreasing size of the adjacent right pulmonary artery. In our patient population with tetralogy of Fallot, right pulmonary artery narrowing is at least partly because of compression from the adjacent enlarged ascending aorta.