Influence of Cryopreservation on Structural, Chemical, and Immunoenzymatic Properties of Aortic Valve Allografts.

OBJECTIVES: The problems in preparing (including cryopreservation) and implanting aortic valve allografts (AVAs) is widely elaborated, but some issues need explanation. MATERIAL AND METHODS: Twenty AVAs cryopreserved in dimethylsulphoxide/RPMI solution under -160°C for 1-15 years and 3 controls stored at +4°C up to 2 weeks, from 19 male and 4 female donors, aged 20-51, ±30.8 years, were examined using light (LM), digital (DM), and scanning electron microscopy (SEM), energy dispersion X-ray spectroscopy (EDS), and enzyme-linked immunosorbent assay immunoenzymatic tests (PECAM1, CD34). RESULTS: All AVAs were macroscopically correct. LM revealed normal structure of leaflets but massive endothelial decellularization (±59 cells remained on the surface of 5 mm scraps). DM and SEM demonstrated generally normal collagen structures, but local alterations, probably influenced by freezing-thawing (gaps, separated plates) or being initial phase of native degeneration (grains). EDS detected a little elevated calcium amount in 1 specimen only. The mean PECAM1 and CD34 concentrations were at similar low level in all probes. CONCLUSIONS: Fresh and cryopreservation technologies did not significantly influence the basic properties of AVA leaflets; however, massive endothelial decellularization was present in both groups. Therefore, no endocardial cell activity nor signs of inflammation were observed. These results were independent of donors' age and sex, processing technology, and time of storage of cryopreserved AVAs.

Allogenic heart valve bank in the Department of Cardiovascular Surgery and Transplantology of Jagiellonian University in Cracow - 23 years experience in the treatment of aortic valve or aortic root diseases.

Allogenic aortic valves are widely used in case of native aortic valve or root disease as well as failed prosthetic valves with great success. At the Department of Cardiovascular Surgery and Transplantology of the Jagiellonian University in Cracow, aortic valve or aortic root replacement with allogenic aortic valve has been performed for 23 years. Allogenic heart valve bank was founded in 1980. In the bank we prepare both aortic allografts for adult cardiac surgical procedures and pulmonary allografts that are mostly used for repair of congenital heart disease.Allogenic aortic valves implantation was usually considered in our clinic for older patients, patients with infective endocarditis of the native or prosthetic valve, young women in reproductive age and patients with Marfan syndrome. Allografts exhibit excellent clinical performance and acceptable durability with no early failure if properly inserted. Between 1980 and 1992, allografts were obtained only from cadavers during routine autopsies. More than 10% of prepared allografts were exported to other cardiac surgery centres in Poland and foreign countries. Aortic valve replacement using allogenic aortic valves can be performed with acceptable mortality and good long-term results. The procedure although surgically more challenging has the advantage of not requiring anticoagulation therapy, hemodynamic performance of the allogenic valve is excellent, it demonstrates freedom from thromboembolism and infective endocarditis. We would like to emphasize the importance and advantages of the fact that allogenic heart valve bank is placed in the department of cardiovascular surgery and it is able to supply the department in heart valve allografts 24 h a day.