CRYOGENIC ARTERIAL THROMBOLYSIS

Twenty experiments were performed in dogs upon frozen thrombosed segments of the femoral artery. The special cryogenic technique is described. The results are demonstrated by arteriograms. The walls of major arteries have a peculiar ability to withstand the effects of extreme cold, relative to other tissues. Freezing and thawing a major artery in the dog, within the time‐temperature parameters described, has thus far not produced rupture or necrosis of the vessel, within a two‐month period of observation. Moreover, blood which is frozen solid within the artery does not clot, but rather is lysed when the vessel thaws, and is carried off as circulation is resumed. This differential effect of extreme cold upon the arterial wall and the circulating blood accounts for the fact that a relatively fresh thrombus within an artery can be lysed by freezing the artery and permitting it to thaw. These observations indicate the possible future application of cryogenic arterial thrombolysis in selected clinical situations. However, many aspects need further experimental investigation. The long‐range effects of extreme cold upon major arteries and veins remain to be elucidated. The possibility of late aneurysm formation or other anatomic changes must be objectively evaluated. The effect of extreme cold upon chronic organized thrombi needs experimental study. In addition, the possible variation of effect upon thrombi of varying etiology, some of which produce pathologic lesions in the arterial wall, must be evaluated. On the basis of our present findings, the technique of cryogenic arterial thrombolysis merits continued investigation.