title: Nonlocalized lower gastrointestinal bleeding: provocative bleeding studies with intraarterial tPA, heparin, and tolazoline.
abstract: OBJECTIVE
  The purpose of this study was to assess the efficacy and safety of provocative mesenteric angiography with tissue plasminogen activator (tPA), heparin, and tolazoline in patients with nonlocalized lower gastrointestinal (LGI) bleeding. Results were examined to assess the clinical impact of the study on patients who had positive or negative results from elective provocative bleeding studies.
  
  
  METHODS
  Seventeen provocative bleeding studies for occult LGI bleeding were performed in 16 patients, nine of whom were women, aged 44-79 years. All patients had negative results from previous endoscopic and angiographic studies. Patients' requirements for blood transfusion ranged from 6 to 69 units. Studies were performed electively. Blood group matching and cross-matching were performed for all patients. To provoke bleeding, a combination of intravenous heparin, intraarterial tolazoline, and intraarterial tPA was used. Doses used included 3,000-10,000 U heparin, 25-100 mg intraarterial tolazoline, and 10-50 mg intraarterial tPA (mean, 20.3 mg). Duration of follow-up was 3-34 months.
  
  
  RESULTS
  Seventeen elective provocative studies were performed in 16 patients with occult LGI bleeding, leading to provoked bleeding in six patients (37.5%). In addition, two previously undiagnosed vascular abnormalities were diagnosed, which did not bleed during provocation. Therefore, an abnormality was identified in eight of 16 patients (50%) overall. There were no procedural complications encountered during or after any of the 17 procedures. In six patients in whom bleeding was successfully provoked, four bleeding episodes occurred in the large bowel and two occurred in the small bowel. Five of the positively provoked patients had a previously positive tagged red cell scintigraphic study. Three patients had superselective embolization at the time of provoked bleeding. Two were treated with estrogen therapy, and one patient was treated palliatively. Five of these six patients required no further therapy for LGI bleeding. Ten patients (including two with vascular abnormalities) did not bleed during the provoked study with tPA. Follow-up of the group of eight patients with completely normal study results ranged from 3 to 34 months in duration, and during the follow-up period, five patients experienced repeated bleeding and one had no further bleeding. One patient was diagnosed with an ileal vascular lesion during subsequent intraoperative enteroscopy and underwent surgical resection. One patient was lost to follow-up.
  
  
  CONCLUSIONS
  Intraarterial provocative mesenteric angiography with heparin, vasodilator, and tPA identified the site of bleeding in 37.5% of patients in our study group and contributed to treatment in 50%. This small study indicates that the procedure appears to be safe, with no complications encountered in this series. Larger prospective studies are needed to fully assess the safety and efficacy of the technique and to optimize the pharmacologic protocol and patient selection.
authors.affiliation: Division of Vascular and Interventional Radiology, Duke University Medical Center, Box 3808, Erwin Road, Durham, North Carolina 27710, USA. mryan98454@yahoo.com
authors.forename: J M
authors.initials: JM
authors.lastname: Ryan
authors.forename: S M
authors.initials: SM
authors.lastname: Key
authors.forename: S A
authors.initials: SA
authors.lastname: Dumbleton
authors.forename: T P
authors.initials: TP
authors.lastname: Smith
mesh_terms: D000328:Adult; D000368:Aged; D000792:Angiography; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage*; D006471:Gastrointestinal Hemorrhage / Q000000981:diagnostic imaging*; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D007269:Injections, Intra-Arterial; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage*; D014043:Tolazoline / Q000008:administration & dosage*; D014665:Vasodilator Agents / Q000008:administration & dosage*
chemical_list: D005343:Fibrinolytic Agents; D014665:Vasodilator Agents; D006493:Heparin; D014043:Tolazoline; D010959:Tissue Plasminogen Activator