Pulmonary allograft conduit repair of tetralogy of Fallot. An alternative to transannular patch repair.

Cryopreserved allograft valves and valved conduits have been used in 122 patients during the past 3 years for surgical repair of congenital heart disease. In 55 of these patients, the right ventricular outflow tract was reconstructed with a pulmonary allograft conduit. Although most children requiring a conduit had complex lesions, 12 patients with tetralogy of Fallot without pulmonary atresia or absent valve syndrome have been treated in this manner since April 1985. Patients were selected for conduit therapy because of congenital or iatrogenic pulmonary artery problems (nine patients had 12 prior shunts) or increased pulmonary vascular resistance. Ages ranged from 7 months to 6 years (mean 3.1 years) and weights from 7.4 to 18.5 kg (mean 12.2 kg). Pulmonary artery conduit size ranged from 16 to 24 mm internal diameter (mean 22 mm). Distal pulmonary artery reconstruction beyond the bifurcation was required in nine patients and the proximal connection was completed with a hood-shaped patch. One operative death (8.3%) occurred at 20 days as a result of severe right ventricular dysfunction. Left pulmonary artery thrombosis was discovered postmortem. Eleven survivors observed for 3 to 37 months (mean 17 months) are without cardiac symptoms. A chronologically overlapping group of tetralogy of Fallot repairs accomplished with a transannular patch was also reviewed. Twenty-five patients aged 2 months to 4 years (mean 1.7 years) and weighing 3.6 to 14.8 kg (mean 9.2 kg) underwent this procedure from April 1983 to January 1987 (seven patients had one prior shunt each). The mortality rate in this group was 28% (six operative deaths and one late death). Of 18 survivors observed from 20 to 60 months (mean 41.4 months), five (28%) have required pulmonary artery conduit reconstruction for chronic right ventricular failure. Postrepair right ventricular/left ventricular pressure ratios were available in 19 patients, including five of seven who died and three of five who required reoperation. The ratios averaged 0.54, which indicates adequate relief of obstruction. The operative mortality rate from a number of series for transannular patch repair of tetralogy of Fallot averages 16%, ranging from 3% to 63%. However, when distal pulmonary artery problems are added as a risk factor this rate rises to 21%, and valved conduit insertion increases the mortality rate (Kirklin and Barratt-Boyes, 1986). Although not clearly superior, pulmonary artery conduit repair of tetralogy of Fallot achieves results comparable with those of transannular patch repair and is recommended as an alternative, particularly when distal pulmonary artery anatomy is abnormal or vascular resistance is elevated.