Effects of cryopreservation on contractile properties of porcine isolated aortic valve leaflets and aortic wall.

AbstractHuman semilunar donor heart valves can be stored in banks, awaiting transplantation. To evaluate the result of the preservation protocols, a quantitative description of the tissue is necessary. In this study we investigated in a quantitative way the contractile properties of fresh and cryopreserved porcine isolated aortic heart valve leaflets in response to a number of endogenous vasoactive compounds. The responses of strips of the aortic wall were included for comparison. Contraction was measured isometrically in response to potassium (K+; 100 mmol/L), 5-hydroxytryptamine (1 nmol/L to 100 μmol/L), noradrenaline (1 nmol/L to 100 μmol/L), endothelin-1 (0.01 nmol/L to 0.3 μmol/L), and prostaglandin F2α (0.1 nmol/L to 10 μmol/L). The pharmacologic parameters EMAX (the maximal response expressed as a percentage of contraction to a 100 mmol/L dose of K+) and EC50 (the concentration that produces 50% of the maximal effect) were calculated for every compound (n = 6 to 7 each). We observed that all specimens contracted in response to potassium. Its magnitude in fresh leaflets equaled 1.6 ± 0.14 mN compared with 26.6 ± 2.6 mN in fresh aortic wall. Noradrenaline, endothelin-1, and prostaglandin F2α all caused contraction in valvular leaflets and aortic wall, whereas 5-hydroxytryptamine caused contraction in the valvular leaflets but relaxation in aortic wall. After cryopreservation, the response to K+ amounted to 24% of the response of the fresh specimens in valvular leaflets (n = 25) and 14% in aortic wall (n = 26). The values of EMAX and EC50 of the responses to noradrenaline, endothelin-1, and prostaglandin F2α remained unchanged. Although the physiologic relevance of contraction of valvular leaflets needs further study, its measurement may provide an additional model to verify the consequences of alternative methods of preservation. (J Thorac Cardiovasc Surg 1997;113:165-72

Degeneration of the pulmonary autograft: An explant study

ObjectiveWe sought to determine the histologic features of pulmonary autografts explanted after the Ross operation.MethodsHistologic sections of 30 explanted autografts and 8 normal heart valves were compared and semiquantitatively scored by a blinded cardiovascular pathologist.ResultsPulmonary autografts (n = 30) were explanted on average 6.1 ± 0.6 years (median, 6.6 years; range, 0.1-11.7 years) after the Ross operation (n = 28) or removed at autopsy (n = 2). Twelve (43%) of the patients undergoing reoperation had no or negligible autograft insufficiency on early transthoracic echocardiography, 12 (43%) had grade 1 autograft insufficiency, and 4 (14%) had grade 1-2 autograft insufficiency. Valve regurgitation with root dilatation was the most common indication for reoperation after root replacement (n = 26 [93%]) and regurgitation after subcoronary implanted autografts (n = 2 [7%]). Microscopy of the autograft explants revealed normal laminar architecture and cellularity. Wall specimens were characterized by reduced and fragmented elastin and increased collagen levels (fibrosis). Medial elastin changes were associated with the presence of hypertrophic smooth muscle cells. Fibrosis was most severe in the adventitia. Intimal thickening was a common finding. Valve explants showed significant thickening caused by fibrocellular tissue on the ventricular surface and marked thickening of the free margin. An autopsy explant with normal function before death showed similar features.ConclusionsPulmonary autograft explants showed severe aneurysmal degeneration of the wall, which was characterized by intimal thickening, medial elastin fragmentation, and adventitial fibrosis. Valve leaflets were thickened. The presence of these features in a nonfailing explant suggests these changes represent a common mode of remodeling

A Population-Based Analysis of Application of WHO Nomenclature in Pathology Reports of Pulmonary Neuroendocrine Tumors

Introduction: Pulmonary neuroendocrine tumors (pNETs) are difficult to classify. We performed a population-based analysis to investigate the application of pNET nomenclature in daily pathology practice. Methods: Conclusions from pathology reports (20032012) describing carcinoids, (large cell) neuroendocrine carcinomas (NECs), and carcinomas with neuroendocrine features/differentiation were retrieved from the Dutch Pathology Registry by queries on location and diagnosis and screened for terminology. Cases with a nonpulmonary or unknown origin and small cell lung cancer were excluded. Diagnoses were clustered into subgroups and the retrieved terminology was compared with the 2015 World Health Organization (WHO) diagnoses. By means of an online questionnaire, interpretation of the non-WHO nomenclature retrieved from pathology reports was evaluated (by 35 physicians and 19 pathologists). Results: A total of 3216 unique pathology report conclusions with 55 different pNET diagnoses (n = 3052) and 20 uncertain diagnoses (n = 164) were analyzed. Non-WHO nomenclature was used in 15% of diagnoses (n = 488). Diagnoses could be clustered into carcinoids (n = 1086), NEC (n = 1316), carcinomas with neuroendocrine features/differentiation (n = 624), and unspecified pNETs (n = 26). Non-WHO nomenclature within these clusters was found for 7% of carcinoids, 20% of NECs, 13% of carcinomas with neuroendocrine features/differentiation, and 100% of unspecified pNETs and was observed more often in conclusions regarding biopsy or cytological specimens (62% and 12%) compared with resection specimens (26%). Analysis of the questionnaire results revealed that 4 of 19 diagnoses based on non-WHO nomenclature were uniformly interpreted (>50% agreement) by physicians, as were 10 of 19 diagnoses by pathologists. Conclusions: In 15% of pNETs other than small cell lung cancer, a non-WHO nomenclature diagnosis was provided, more frequently on the basis of smaller specimens. The interpretation was different between physicians and pathologists. Application of uniform nomenclature among all clinicians is advocated. (C) 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved