Addition of Calcium to Euro-Collins Solution Is Essential for 24-Hour Preservation of the Vasculature

Background. Genuine Euro-Collins solution is calcium free. The aim of this study was to investigate whether the addition of calcium would improve its capacity to preserve the vasculature. Methods. The infrarenal aorta of Sprague-Dawley rats was investigated in organ baths: as fresh controls, after 24 hours of cold (4°C) storage in Euro-Collins solution, or in Euro-Collins solution with the addition of calcium in amounts ranging from 0.05 to 1.5 mmol/L. The thromboxane analogue U-46619 was used to investigate contractility. Endothelium-dependent relaxation was tested by cumulative addition of acetylcholine. Papaverine was used to elicit endothelium-independent relaxation. Investigation by transmission electron microscopy was also performed. Results. Storage of rat aorta for 24 hours in genuine Euro-Collins solution almost abolished smooth muscle function, and severe edema was found in the endothelial cells. However, if calcium was added, the rat aorta could be stored for 24 hours without affecting smooth muscle function, and endothelium-dependent relaxation was only slightly reduced. Furthermore, only slight edema could be demonstrated in the endothelial cells. Conclusions. If calcium is added to Euro-Collins solution in amounts ranging from 0.4 to 1.5 mmol/L, it allows good preservation of rat aorta for 24 hours. Without calcium, this solution destroys both the function and morphology of the vessels. (Ann Thorac Surg 1997;63:408–13)