A large spectrum of cardiac tumors is observed in the surgical pathology practice. Although the diagnosis of cardiac masses is easily attainable by routine imaging techniques, differential diagnosis between primary and secondary tumors, malignant and benign forms, and non neoplastic masses, is achievable only by a thorough microscopic study of surgical resections. The role of the cardiac pathologist is becoming crucial as in other fields of oncology.

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Two multistep extractions were achieved on porcine aortic tissues to obtain acellular matrices used for cardiac bioprostheses. The evaluation of structural modifications and the possible damage of extracellular matrix fibrous proteins were investigated by means of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Protein-water interactions and degradation temperatures were determined by TGA. DSC was used to characterize protein thermal transitions (glass transition and denaturation), which provided information on the dynamic structure of the aortic tissue components. Sodium dodecyl sulfate (SDS) extraction had a destructuring effect, while Triton and cholate treatments did not affect the structural integrity of either elastin and collagen. A DSC comparison showed that SDS destabilizes the collagen triple helical domain and swells the elastin network.

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Extracellular matrix (ECM) scaffolds isolated from valvulated conduits can be useful in developing durable bioprostheses by tissue engineering provided that anatomical shape, architecture, and mechanical properties are preserved. As evidenced by SEM, intact scaffolds were derived from porcine aortic valves by the combined use of Triton X-100 and cholate (TRI-COL) or N-cetylpyridinium (CPC) and subsequent nucleic acid removal by nuclease. Both treatments were effective in removing most cells and all the cytomembranes, with preservation of (1) endothelium basal membranes, (2) ECM texture, including the D-periodical interaction of small proteoglycans with normally D-banded collagen fibrils, and (3) mechanical properties of the treated valves. Ultrastructural features agreed with DNA, hexosamine, and uronic acid biochemical estimations. Calcification potential, assessed by a 6-week rat subdermal model, was significantly reduced by TRI-COL/nuclease treatment. This was not true for CPC only, despite better proteoglycan preservation, suggesting that nucleic acids also are involved in calcification onset. Human fibroblasts, used to repopulate TRI-COL samples, formed mono- or multilayers on surfaces, and groups of cells also were scattered within the valve leaflet framework. A biocompatible scaffolds of this kind holds promise for production of durable valve bioprostheses that will be able to undergo probable turnover and/or remodeling by repopulating recipient cells.

Mechanical valves have a low incidence of reoperation, mostly for prosthetic dehiscence. Pannus development is the next frequent complication increasing with time since implant, therefore in this series it was related to old valvular models and tilting disk prosthesis, with longer follow-up. Acute thrombosis occurs significantly earlier than pannus formation. Despite shorter follow-up we are therefore confident that bileaflet prostheses are less prone to this complication and pannus is a rare early etiologic factor. Thrombosis has very high operative risk as compared to pannus, justifying the present trend to thrombolysate selected cases.

Collectively, these findings are consistent with the contention that endothelial damage occurs in most patients with atherosclerosis and/or hypertension and that ET-1 is synthesized in VSMCs of these patients.