Functional and Morphological Changes of the Small Bowel after Experimental Embolic Occlusion and Local Thrombolysis of the Superior Mesenteric Artery

Abstract

Following embolization of the superior mesenteric artery with autologous blood clots, local catheter thrombolysis using streptokinase was performed in 14 pigs. In 7 animals the abdomen was kept closed during the time of obstruction (3 h) and subsequent lysis (up to 3 h) until angiography revealed patent vessels. Macroscopic and histologic examination showed small bowel distension and severe mucosal damage in all animals. In a second series of 7 pigs, lysis was performed after 1 2 and 3 h of ischemia. Angiographic and histologic findings were compared with surface oxygen tension and myoelectrical activity. Bowel wall anoxia and disappearance of slow waves were reversible after up to 4 h of ischemia (2 h occlusion, 1–2 h lysis). Persistent anoxia and irreversible disappearance of slow waves in combination with severe mucosal damage were suggestive of pregangrenous alterations of the small bowel despite a normal angiographic pattern beyond 3 h of obstruction and successful lysis. The results demonstrate that angiography alone is of poor predictive value in determining bowel viability in acute intestinal ischemia.

Acute Mesenteric Ischemia: Multidisciplinary Therapeutic Concept

“…As demonstrated in pigs, angiography alone does not prove bowel viability [ 14]. Since urokinase can induce an acute severe bowel hemorrhage, the viability of the bowel has to be controlled by an exploratory laparotomy after vasodilator therapy.…”