title: Prolongation of RV-PA conduit life span by percutaneous stent implantation. Intermediate-term results.
abstract: 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 progressive obstruction and require surgical replacement. This report reviews our experience implanting balloon-expandable stents to relieve conduit obstruction and delay reoperation.
  
  
  RESULTS
  A retrospective review identified 44 patients who underwent placement of 48 stents in obstructed RV-PA conduits. Median patient age was 6.9 years (range, 7 months to 30 years), and median follow-up time was 14.2 months (range, 0 to 48 months). Stent implantation initially decreased the RV-PA pressure gradient from 61.0 +/- 16.9 to 29.7 +/- 11.9 mm Hg (P < or = .001) and the right ventricular-to-systemic arterial pressure ratio from 0.92 +/- 0.17 to 0.63 +/- 0.20 (P < or = .001). The diameter of the stenotic region expanded from 9.3 +/- 3.5 to 12.3 +/- 3.3 mm in the anteroposterior view (P < or = .001) and from 6.6 +/- 2.9 to 10.9 +/- 2.5 mm in the lateral view (P < or = .001). During the follow-up period, 2 patients had their stents redilated, 7 had additional conduit stents deployed, and 14 underwent surgical replacement of their conduits. Actuarial freedom from conduit reoperation was 65% at 30 months postprocedure. Seven patients were found to have fractured stents on follow-up, suggesting an important role for external compressive forces in conduit failure. Recatheterization in 16 patients a median of 11.8 months (3 to 48 months) postprocedure demonstrated hemodynamic evidence of recurrent obstruction despite sustained enlargement at the previously stented sites. Complications included stent displacement (n = 1), bacterial endocarditis (n = 1), and false aneurysm formation (n = 1). One patient died awaiting conduit replacement surgery.
  
  
  CONCLUSIONS
  Stent implantation in obstructed RV-PA conduits results in significant immediate hemodynamic and angiographic improvement. In a subgroup of patients, the procedure prolongs conduit life span by several years and increases the interval between conduit reoperations. Recurrent obstruction is caused by external compression and progressive stenosis outside the stented region.
authors.affiliation: Department of Cardiology, Children's Hospital, Harvard Medical School, Boston, Mass. 02115, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Powell
authors.forename: J E
authors.initials: JE
authors.lastname: Lock
authors.forename: J F
authors.initials: JF
authors.lastname: Keane
authors.forename: S B
authors.initials: SB
authors.lastname: Perry
mesh_terms: D001705:Bioprosthesis; D001807:Blood Vessel Prosthesis; D006328:Cardiac Catheterization; D002648:Child; D004868:Equipment Failure; D005260:Female; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000628:therapy*; D006330:Heart Defects, Congenital / Q000453:epidemiology / Q000601:surgery*; D006350:Heart Valve Prosthesis; D006352:Heart Ventricles / Q000601:surgery; D006801:Humans; D008297:Male; D011651:Pulmonary Artery / Q000601:surgery*; D011859:Radiography; D012189:Retrospective Studies; D015607:Stents; D013997:Time Factors