PROLONGATION OF RV-PA CONDUIT LIFE-SPAN BY PERCUTANEOUS STENT IMPLANTATION - INTERMEDIATE-TERM RESULTS

Background Right ventricle-to-pulmonary artery (RV-PA) homografts and bioprosthetic conduits are commonly used to palliate various types of complex congenital heart disease. These conduits frequently develop pr ogressive obstruction and require surgical replacement. This report re views our experience implanting balloon-expandable stents to relieve c onduit obstruction and delay reoperation. Methods and Results A retros pective review identified 44 patients who underwent placement of 48 st ents in obstructed RV-PA conduits. Median patient age was 6.9 years (r ange, 7 months to 30 years), and median follow-up time was 14.2 months (range, 0 to 48 months). Stent implantation initially decreased the R V-PA pressure gradient from 61.0+/-16.9 to 29.7+/-11.9 mm Hg (P less t han or equal to.001) and the right ventricular-to-systemic arterial pr essure ratio from 0.92+/-0.17 to 0.63+/-0.20 (P less than or equal to. 001). The diameter of the stenotic region expanded from 9.3+/-3.5 to 1 2.3+/-3.3 mm in the anteroposterior view (P less than or equal to.001) and from 6.6+/-2.9 to 10.9+/-2.5 mm in the lateral view (P less than or equal to.001). During the follow-up period, 2 patients had their st ents redilated, 7 had additional conduit stents deployed, and 14 under went surgical replacement of their conduits. Actuarial freedom from co nduit reoperation was 65% at 30 months postprocedure. Seven patients w ere found to have fractured stents on follow-up, suggesting an importa nt role for external compressive forces in conduit failure. Recatheter ization in 16 patients a median of 11.8 months (3 to 48 months) postpr ocedure demonstrated hemodynamic evidence of recurrent obstruction des pite sustained enlargement at the previously stented sites. Complicati ons included stent displacement (n=1), bacterial endocarditis (n=1), a nd false aneurysm formation (n=1). One patient died awaiting conduit r eplacement surgery. Conclusions Stent implantation in obstructed RV-PA conduits results in significant immediate hemodynamic and angiographi c improvement. In a subgroup of patients, the procedure prolongs condu it life span by several years and increases the interval between condu it reoperations. Recurrent obstruction is caused by external compressi on and progressive stenosis outside the stented region.