Provocative Angiography

Abstract

Determination of the site and etiology of lower gastrointestinal (GI) bleeding may lead to frustration for internists, gastroenterologists, surgeons, diagnostic, and interventional radiologists. The intermittent nature, variable severity, and changes in patient hemodynamic status can result in multiple rounds of diagnostic imaging without an answer. This is especially true in the setting of negative upper endoscopy and limited lower endoscopy due to the amount of blood within the colon. Despite significant blood loss, traditional diagnostic examinations such as tagged red cell scans may be negative or positive without definitive localization of the responsible site. Mesenteric angiography is the definitive imaging tool for localization of the bleeding site. This can, however, lend to confusion when multiple vascular lesions are identified without visible bleeding. With the addition of super-selective microcatheter embolization, angiography has become both diagnostic and therapeutic, and in many institutions, the first-line intervention for the management of lower GI bleeding. The main limitations of angiographic detection are the temporal relation of the arteriogram to the intermittent nature of the bleed, as well as the volume of bleeding. To help improve the sensitivity of angiography, practices have combined catheter-based delivery of pharmacologic agents with intermittent angiography in hopes of increasing the yield of angiography without compromising safety or efficacy. Now, known as provocative angiography, this technique has been applied to assess fore-, mid-, and hindgut bleeding that is refractory to traditional diagnostic and therapeutic modalities.