[Mechanisms of mineralization of aortic xenograft bioprostheses in young patients].

The results of mitral valve replacement with aortic xenobioprostheses in 15 patients, aged 14 to 20 years, are presented, the follow-up reaching 7 years. The bioprostheses functioned normally 1.5-2 months after the operation.

[The role of biopsy of the human myocardium in cardiological and cardiosurgical centers].

Endomyocardial puncture biopsy is practicable for elucidating etiology (nosology), differential diagnosis, the determination of activity of rheumatism or nonspecific myocarditis, the assessment of treatment efficiency and prognosis of outcome. Incision intraoperative biopsy should be used to evaluate the efficiency of myocardial protection and the specifics of metabolism and function of the myocardial cell. Open incision intraoperative myocardial biopsy is more informative than the endomyocardial puncture biopsy as it provides a heart specimen where all layers are represented, so that the number of negative results attributable to the mosaic pattern of myocardial abnormality is reduced.

[Evaluation of the efficacy of human heart protection during cardioplegia].

Materials from 546 intraoperative incision biopsies from 253 patients were studied in order to assess the effectiveness of myocardium protection during operations on the open heart. No significant ultrastructural, metabolic or functional changes develop in the myocardium upon pinching of the aorta and ischemia for 10 min, therefore myocardium protection is unnecessary. In ischemia for up to 40 min ultrastructural changes in cardiomyocytes are reversible therefore deep hypothermia proved to be sufficient for myocardium protection.

[Morphology of transplanted valves in patients with acquired heart defects].

The investigation was based on the examinations of 85 aortal valves of man and swine after conservation in 1% betapropiolactone solution, 4% formaldehyde solution, 0.6% glutaraldehyde solution and after treatment with gamma-rays preceded by freezing. Besides, 38 allo- and xenotransplants of valves preserved by the above methods which had functioned in the mitral and tricuspidal positions in patients for 1 day to 9 years were examined.