Case Reference No. CC-597-09 The patient is a 71-year-old woman with a history of sudden, recurrent lower gastrointestinal bleeding requiring multiple blood transfusions on her current admission. Two colonoscopies and a scintigraphic bleeding scan failed to demonstrate an etiology for the hemorrhage. Notably, two bleeding episodes occurred within hours of heparinization during cardiac catheterizations. Neither episode was massive or life-threatening. At the time of referral there was no active bleeding. We chose to perform a "provocative" heparin challenge mesenteric arteriogram to search for the bleeding site. Two hours before the arteriogram, a 5000-unit bolus of heparin was administered, followed by a 1,000 unit/hour IV drip. An active lower gastrointestinal bleed started approximately 30 minutes before the scheduled time of the arteriogram. The IMA arteriogram was normal. The SMA arteriogram demonstrated active extravasation of contrast material in the region of the cecum, indicating active gastrointestinal hemorrhage; its angiographic appearance was nonspecific. The heparin was stopped.

Fig. 1. SMA arteriogram shows early extravasation in the cecal region. Fig. 2. A later phase image shows further, more distinct, bleeding in the cecal region (arrow).

The bleeding ceased, and the patient remained clinically stable. The next day the patient underwent a right hemicolectomy. Curiously, pathological examination of the cecum failed to demonstrate a bleeding site. Questions 1) We found two articles about the use of pharmacoangiography in the diagnosis of lower gastrointestinal hemorrhage: Rosch J, et al. Pharmacoangiography in the diagnosis of recurrent massive lower gastrointestinal bleeding. Radiology 1982; 145(3):615­619. Koval G, et al. Aggressive angiographic diagnosis in acute lower gastrointestinal hemorrhage. Dig Dis Sci 1987; 32(3):248­253. Is anyone familiar with any more recent publications addressing this issue? 2) Does anyone have much experience using heparin challenges to angiographically provoke recurrent occult GI bleeding in order to diagnose it angiographically? If so, what is your technique and what are some of the technical issues involved? Is surgical emergency back-up always arranged? What doses of heparin are used, etc.? 3) Has anyone had experience with other "provocative" pharmacoangiographic methods such as systemic and/or subselective mesenteric administration of vasodilators and/or fibrinolytic agents (urokinase or tPA)?