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Objectives: Bioprosthetic pulmonary valve conduits have been reported with an increased risk of endocarditis. Thrombus formation is considered as source of these serious and life-threatening infections. We reviewed a series of explanted valved pulmonary conduits for histological evidence for thrombus formation., Materials and Methods: Explanted bioprosthetic pulmonary valves were fixed in formalin and embedded in paraffin or in methylmethacrylate. Standard staining as well as immunohistochemical staining techniques were applied. Native pulmonary valves of German domestic pigs served as controls., Results: 47 valved pulmonary conduits (Hancock n = 23, Homograft n = 7, Contegra n = 7, Melody n = 7, other n = 3) were analyzed histologically. Average time of implantation had been 63 months (6 to 342 months). Indications for explantation included significant obstruction (n = 45), regurgitation (n = 7), and/or endocarditis (n = 6). In 44/47 (93%) specimen, we found accumulation of thrombotic material at the basis of the semilunar valve sinus to a variable degree. 11 patients had been treated with antiplatelet agents, 2 had received anticoagulants at the time of explantation. There was no suspicion of thrombus formation clinically or echocardiographically prior to explantation in any of the patients. Control porcine pulmonary valves (n = 5) did not show any evidence of accumulation of thrombotic material., Conclusions: In a large series of explanted valved pulmonary conduits, formation of subclinical, mostly non-infectious thrombotic material was an almost ubiquitous finding. We speculate that high incidence of endocarditis in bioprosthetic valves may in part be explained by thrombus apposition at the basis of conduit valve sinus., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Abstract: Objective: Allograft conduits are used for reconstruction of the right ventricular outflow tract in congenital heart malformations (biventricular repair) and autograft procedures. A retrospective evaluation of allograft reconstruction of the right-ventricular-outflow-tract reconstruction was conducted and a cross-sectional quality of life study was performed. Methods: Between August 1986 and March 2009, 509 allografts (435 pulmonary and 74 aortic) were implanted in 463 pediatric and adult patients (308 right-sided congenital heart malformations and 155 autograft procedures). Perioperative and follow-up data were collected and analyzed. Kaplan–Meier analyses were done for survival, valve-related re-operation, and valve-related events. Cox regression analysis was used for evaluation of potential risk factors. In addition, the Short Form-36 was presented to patients to assess the perceived quality of life. The results of the Short Form-36 were compared to age-adjusted Dutch population norms. Results: The mean age at allograft implantation was 19 years (1 week–66 years). Mean follow-up was 9 years (2 days–22 years). Forty-eight patients died during follow-up. Patient survival was 93% at 10 years and 88% at 15 years. A total of 63 re-operations were required for allograft dysfunction in 58 patients. Freedom from valve-related re-operation was 89% at 10 years and 81% at 15 years. Freedom from valve-related events was 86% at 10 years and 74% at 15 years. Younger patient age (p =0.007) and the use of an aortic allograft (p <0.001) were identified as independent risk factors for allograft re-operation. Patients between 14 and 40 years scored significantly lower on ‘physical functioning’ and ‘general health’ subscales than the general Dutch population, but scored better on the subscales ‘emotional role functioning’ and ‘bodily pain’. Except for the subscale ‘general health’, on which patients within our study population scored lower, patients between 41 and 60 years had comparable average scores as the general Dutch population. The older patient group (61 years or older) had a better average score on the subscale ‘bodily pain’ and similar scores on other subscales with respect to the general Dutch population. Conclusions: Right-ventricular-outflow-tract reconstruction with an allograft conduit can be performed with good patient survival, acceptable long-term allograft durability, and good perceived quality of life. [Copyright &y& Elsevier]