title: Evaluation of cryopreserved homografts in the right ventricular outflow tract after the Ross procedure: intermediate-term follow up.
abstract: OBJECTIVE
  The Ross procedure involves replacing a transplanted pulmonary valve with a cryopreserved homograft in order to re-establish right ventricle-pulmonary artery continuity. This study reviews mid-term results of such surgery in children and young adults.
  
  
  METHODS
  Since November 1986, 114 patients have undergone the Ross procedure at the Children's Hospital of Oklahoma using cryopreserved pulmonary homografts (n = 113) and aortic homograft (n = 1) to reconstruct the right ventricular outflow tract. Graft size ranged from 16 to 32 mm. Ninety-three patients (mean age at implant 10.4 years (range: 0.8-22 years) have had complete mean follow up of 3.2 years (range: 5 months to 8.4 years) after surgery. Homograft evaluation included clinical reports and comparison of early post-implant and latest echocardiography. Measurements of homograft valve annulus and peak instantaneous Doppler gradient were compared; quality of valve leaflets, location of obstruction, and the degree of pulmonary regurgitation were assessed.
  
  
  RESULTS
  Compared with early postoperative data, mean homograft annulus size decreased by 15% (p < 0.0001); in 88% of patients, the decrease ranged from one to nine millimeter. Peak Doppler gradient increased significantly (from 10 to 17 mmHg, p < 0.0001); 25% of patients developed gradients > 25 mmHg, and four had gradients > 50 mmHg. Significant obstruction developed most often at the supravalvular level or in the homograft conduit itself. This usually occurred within one year of implant, and was associated with calcification and contracture of the homograft wall. Significant pulmonary regurgitation developed in 19 cases (20%), but was more than mild in only three. Leaflet integrity was maintained except in those who developed severe stenosis or regurgitation. Two patients have undergone re-operation for homograft stenosis 2.8 and 5.4 years respectively after the Ross procedure; one has developed recurrent severe stenosis in the homograft four months later.
  
  
  CONCLUSIONS
  After the Ross procedure: (i) Pulmonary homografts undergo significant annular reduction in most patients, though this is usually not associated with the development of significant obstruction. (ii) Peak Doppler gradients across the homograft increase in most patients, though only 4% develop more than mild obstruction. (iii) Mild pulmonary regurgitation is common (20%); moderate or severe regurgitation is rare and usually develops in concert with severe stenosis. (iv) Severe homograft valve degeneration usually occurs within one year of implant, and may reflect an immune-mediated response.
authors.affiliation: Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, USA.
authors.forename: K E
authors.initials: KE
authors.lastname: Ward
authors.forename: R C
authors.initials: RC
authors.lastname: Elkins
authors.forename: E D
authors.initials: ED
authors.lastname: Overholt
authors.forename: C J
authors.initials: CJ
authors.lastname: Knott-Craig
authors.forename: J D
authors.initials: JD
authors.lastname: Razook
authors.forename: M M
authors.initials: MM
authors.lastname: Lane
authors.forename: S S
authors.initials: SS
authors.lastname: Gilliland
mesh_terms: D000293:Adolescent; D000328:Adult; D001011:Aorta / Q000637:transplantation*; D002648:Child; D002675:Child, Preschool; D015925:Cryopreservation; D015150:Echocardiography, Doppler; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006085:Graft Survival; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging / Q000601:surgery*; D006352:Heart Ventricles / Q000002:abnormalities / Q000601:surgery*; D006801:Humans; D007223:Infant; D008297:Male; D011379:Prognosis; D011651:Pulmonary Artery / Q000637:transplantation*; D011665:Pulmonary Valve Insufficiency / Q000000981:diagnostic imaging / Q000209:etiology; D011859:Radiography; D012086:Reoperation; D016378:Tissue Transplantation / Q000379:methods*; D014184:Transplantation, Homologous; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery