Cell Viability Assessment Using Fluorescence Vital Dyes and Confocal Microscopy in Evaluating Freezing and Thawing Protocols Used in Cryopreservation of Allogeneic Venous Grafts.

The authors present their contribution to the improvement of methods suitable for the detection of the freezing and thawing damage of cells of cryopreserved venous grafts used for lower limb revascularization procedures. They studied the post-thaw viability of cells of the wall of cryopreserved venous grafts (CVG) immediately after thawing and after 24 and 48 h culture at +37 °C in two groups of six CVG selected randomly for slow thawing in the refrigerator and rapid thawing in a water bath at +37 °C. The grafts were collected from multi-organ and tissue brain-dead donors, cryopreserved, and stored in a liquid nitrogen vapor phase for five years. The viability was assessed from tissue slices obtained by perpendicular and longitudinal cuts of the thawed graft samples using in situ staining with fluorescence vital dyes. The mean and median immediate post-thaw viability values above 70% were found in using both thawing protocols and both types of cutting. The statistically significant decline in viability after the 48-h culture was observed only when using the slow thawing protocol and perpendicular cutting. The possible explanation might be the "solution effect damage" during slow thawing, which caused a gentle reduction in the graft cellularity. The possible influence of this phenomenon on the immunogenicity of CVG should be the subject of further investigations.

Differential impact on acute kidney injury incidence between on- and off pump coronary artery bypass grafting in octogenarians.

INTRODUCTION: Acute kidney injury (AKI) following surgical myocardial revascularization is associated with high mortality and morbidity. The aim of this study was to evaluate the risk of acute kidney injury in a population of very old patients following different surgical techniques. PATIENTS AND METHODS: A retrospective study of 310 consecutive patients aged 78 to 93 years, mean 80.5±2.2, who underwent surgery at one cardiac surgery centre. Based on the surgical technique used the patients were divided into: Group I. CABG (n=134) - surgical myocardial revascularization using extracorporeal circulation and arterial and venous grafts. Group II. OPCABG (n=55) - surgical revascularization without extracorporeal circulation but using arterial and venous grafts. Group III. NOTOUCH (n=121) - no handling with the ascending aorta was performed at all. RESULTS: A statistically insignificant renoprotective trend was found in patients who underwent surgery without extracorporeal circulation regardless of technique. Comparing groups II and III vs. group I, a significantly poorer renal functioning (median difference in creatinine was 10.0 (32.9) vs 17.5 (35.0), P=0.05) was shown for patients in group I. CONCLUSION: Surgical myocardial revascularization without extracorporeal circulation in very old patients is safe. The results of this study show a renoprotective trend.