Vascular freezing--a new method for immediate and permanent vasospasm relief: an experimental study in the rat

Although much work has been done on the etiology and prevention of vasospasm, a spasmolytic agent capable of firmly protecting against or reversing vasospasm has not yet been found. In this paper, we describe a new physical method of treating vasospasm. It consists of directly freezing the arterial walls. Experiments were performed on the epigastric artery of 40 female Sprague-Dawley rats. A vasospasm was created by mechanical vessel manipulation. The vasospasm was treated by freezing the vessel walls with a dermatologic hand-held liquid nitrogen spray. Vascular spasm and patency controls were made immediately after thawing and 30 minutes and 3, 10, and 120 days after freezing. Epigastric island flaps were harvested based on the frozen artery at 3, 10, and 120 days after the freezing procedure. Histologic studies also were effectuated 3, 10, and 120 days after the freezing procedure. Relief from vasospasm was instantaneous and permanent. After freezing, almost all the cells in the media and endothelium died and the adrenergic fibers degenerated. This was followed by a phagocytic debridement, complete regeneration of the endothelium, and a limited regeneration of the muscle fibers in the media. The adrenergic innervation was recovered, and no alterations in the adrenergic fibers distal to the lesion were noted at any time. None of the arteries examined underwent thrombosis, and all the flaps harvested survived very well, indicating that the vascular bed distal to the site of the freezing was normal. This vascular freezing technique may well have clinical applications for microsurgical transfers and for the prophylactic treatment of vasospasm disease. However, its indications still require clarification.