ADAPT-treated pericardium for aortic valve reconstruction in congenital heart disease: histological analysis of a series of human explants.

OBJECTIVES: Different types of patch materials are used for aortic valve repair in children with congenital aortic valve disease to avoid early valve replacement. CardioCel© (Admedus, Toowong, QLD, Australia) consists of bovine pericardium treated with the ADAPT method (Admedus' proprietary tissue engineering process). METHODS: Our goal was to describe tissue reactions in 12 explanted aortic valve leaflet specimens (augmented or replaced with CardioCel patch material) (11 explanted surgically, 1 autopsy). Explantation was performed during reoperation after aortic valve repair, necessitated by aortic valve stenosis in 5, aortic valve insufficiency in 2, combined aortic valve lesions in 3 patients and endocarditis in 1 patient. One patient died of sudden left heart failure 28 months after aortic valve repair. At the last documented follow-up of this patient at 22 months, he showed mild aortic valve stenosis and insufficiency. Implantation time (time between implantation and explantation) of CardioCel patches was a median of 25 (range 11-47) months. Explants were examined using a uniform protocol with methylmethacrylate and/or paraffin embedding after fixation in formalin. Besides standard histological staining, von Kossa (for identification of calcifications) and immunohistochemical stains were applied with antibodies specific for muscular, inflammatory and connective tissue component antigens. Findings regarding the extent of appositional growth on top of the patch consisting of fibroblasts and extracellular matrix components, calcification, and inflammation were rated using a 4-grade scale (G0 no/G1 few/G2 moderate/G3 massive). RESULTS: Superficial endothelialization was demonstrated in all patients by immunohistochemical analysis. Nine specimens showed mild inflammatory cell infiltration (G1) (G2: n = 3). Significant appositional growth on top of the patch due to addition of fibroblasts and extracellular matrix components, was seen in all specimens (G1: n = 1; G2: n = 7; G3: n = 4). Ten of 12 samples with implant times of 23 months or longer revealed calcifications (G1: n = 6; G2: n = 3; G3: n = 1). Two specimens with the shortest implant times (11 and 20 months) showed no calcifications (G0). Thrombus apposition with granulocyte infiltration was demonstrated in the specimen of the patient with endocarditis. CONCLUSIONS: In our cohort, all CardioCel patches used for aortic valve repair in patients with congenital heart disease demonstrated appositional growth of fibroblasts and extracellular matrix components, and calcification after an implant time of at least 23 months.

Results of aortic valve repair using decellularized bovine pericardium in congenital surgery.

OBJECTIVES: The search for an optimal patch material for aortic valve reconstruction (AVR) is an ongoing challenge. In this study, we report our experience of AVR using decellularized bovine pericardial patch material in congenital heart surgery. METHODS: Data of 40 consecutive patients who underwent AVR using the CardioCel® patch (Admedus Regen Pty Ltd, Perth, WA, Australia) between February 2014 and August 2016 were retrospectively reviewed. The median age of the patients at operation was 9 (2-34) years, and 18 patients were younger than 7 years. Twenty-six patients initially presented with aortic valve insufficiency (AI) and 14 with stenosis. Clinical and echocardiographic data were available until August 2017 for a median postoperative follow-up (FU) of 22 (6-42) months. RESULTS: Nine of 40 (23%) patients experienced an event during FU (death: n = 1, 2.5%; reoperation: n = 8, 20%). Overall, the probability of freedom from reoperation or death was 97 ± 3%, 76 ± 9% and 57 ± 12% at 12, 24 and 36 months of FU, respectively. Reason for reoperation was stenosis in 3 (37.5%) patients, insufficiency in 4 (50%) patients and 1 (12.5%) patient was diagnosed with aortic valve endocarditis. Of the remaining 31 patients, 2 patients are scheduled for reoperation (aortic valve stenosis: n = 1 and AI: n = 1) and 9 patients exhibit worsening of aortic valve function with moderate AI. Freedom from developing combined end point [death/reoperation/moderate degree of aortic valve dysfunction (aortic valve stenosis, AI)] after AVR was 92 ± 5%, 55 ± 9% and 28 ± 9% at 12, 24 and 36 months, respectively. CONCLUSIONS: AVR using decellularized bovine pericardial patch material in patients with congenital aortic valve disease show unsatisfactory results within the first 3 years of FU.