Augmentation of Pulmonary Arterial Growth in Single Ventricle Patients by Interim Selective Shunts

Stenosis or diffuse hypoplasia of central pulmonary arteries (PA) is common in patients with single ventricle physiology, often requiring surgical patching. Such repairs are prone to failure, particularly with low pressure venous flow (bidirectional cavopulmonary connection or Fontan). We describe our experience of disconnection of central PA and selective systemic-PA shunt to the hypoplastic vessel. Single ventricle patients (n = 12) with diffuse left pulmonary artery (LPA) hypoplasia (LPA:right pulmonary artery diameter <0.7) underwent PA disconnection (ligation clip) and selective arterial shunt to the LPA. Patients with ≤mild atrioventricular valve regurgitation, and no more than mild systolic dysfunction on echocardiogram were considered. Following systemic-LPA shunt, patients were reassessed by cardiac catheterization prior to further surgery, with follow-up catheterization later performed and description of changes observed. Increased volume loading was well tolerated with no greater than mild atrioventricular valve regurgitation and preserved systolic function (normal or mildly reduced). Selective arterial shunting increased the caliber of the LPA from 4.1 mm (1.2-5.6) to 6.5 mm (1.7-11.9) and this increase was preserved post-Fontan (6.7 mm [1.3-8.0]) (median [range]). Ventricular end diastolic pressure increased with arterial shunting but resolved after shunt takedown and Fontan completion (median +3 and -4 mm Hg respectively). Post-Fontan hospital length of stay was not prolonged (median 11 days, range 7-14). No deaths occurred. In univentricular hearts and PA hypoplasia, selective systemic-PA shunting physiologically increases the caliber of the distal vessels. In selected patients this can be done safely with maintenance of PA growth and resolution of the elevated end diastolic pressure with Fontan completion.