Urokinase in gastrointestinal tract bleeding

Provocative mesenteric angiography for occult gastrointestinal bleeding: a systematic review

Occult gastrointestinal bleeding (GIB) is a challenge for physicians to diagnose and treat. A systematic literature search of the PubMed and Embase databases was conducted up to January 1, 2023. Eligible studies included primary research studies with patients undergoing provocative mesenteric angiography (PMA) for diagnosis or localization of occult GIB. Twenty-seven articles (230 patients) were included in the review. Most patients (64.8%) presented with lower GIB. The average positivity rate for provocative angiography was 48.7% (58% with heparin and 46.7% in thrombolytics). Embolization was performed in 46.4% of patients, and surgical management was performed in 37.5%. Complications were rare. PMA can be an important diagnostic and treatment tool but studies with high-level evidence and standardized protocols are needed to establish its safety and optimal use.

Emerging role of LINC00461 in cancer

LINC00461 is located in the intergenic region between the protein-coding genes MEF2C and TMEM161B. LINC00461 upregulation was associated with the risk of 13 tumors and was strongly associated with clinicopathologic features and poor prognosis in 11 tumors. LINC00461 is involved in resistance to four anticancer drugs, including sunitinib for renal cell carcinoma, cisplatin for head and neck squamous cell carcinoma and rectal cancer, temozolomide for glioma, and docetaxel for breast cancer. LINC00461 can sponge 18 miRNAs to form a complex ceRNA network that regulates the expression of a large number of downstream genes. LINC00461 is involved in the MAPK/ERK signaling pathway and PI3K/AKT signaling pathway, thereby promoting tumorigenesis. Notably, knockdown of LINC00461 in exosomes antagonizes tumor cell proliferation in multiple myeloma. This article summarizes the diagnostic, prognostic, and therapeutic value of LINC00461 in various tumors, and systematically describes the ceRNA network and signaling pathways associated with LINC00461, providing potential directions for future LINC00461 research.

Use of provocative angiography to localize site in recurrent gastrointestinal bleeding

BACKGROUND

While the source of most cases of lower gastrointestinal bleeding may be diagnosed with modern radiological and endoscopic techniques, approximately 5% of patients remain who have negative endoscopic and radiological investigations [1].

CLINICAL PROBLEM

These patients require repeated hospital admissions and blood transfusions, and may proceed to exploratory laparotomy and intraoperative endoscopy. The personal and financial costs are significant.

METHOD OF DIAGNOSIS AND DECISION MAKING

The technique of adding pharmacologic agents (anticoagulants, vasodilators, fibrinolytics) during standard angiographic protocols to induce a prohemorrhagic state is termed provocative angiography. It is best employed when significant bleeding would otherwise necessitate emergency surgery.

TREATMENT

This practice frequently identifies a bleeding source (reported success rates range from 29 to 80%), which may then be treated at the same session. We report the case of a patient with chronic lower gastrointestinal hemorrhage with consistently negative endoscopic and radiological workup, who had an occult source of bleeding identified only after a provocative angiographic protocol was instituted, and who underwent succeeding therapeutic coil embolization of the bleeding vessel.

Reteplase provocative visceral arteriography

GOALS

To present the results of a new protocol for provocative visceral arteriography.

BACKGROUND

Acute lower gastrointestinal hemorrhage (LGIB) usually stops spontaneously. In the absence of an identifiable source, if bleeding is recurrent, provocative visceral arteriography has been advocated for diagnosis. Prior studies using Streptokinase, Urokinase, or tissue plasminogen activator have reported a 33% to 37.5% rate of identifying the site of hemorrhage.

STUDY

We report a retrospective analysis of 9 patients in whom provocative visceral arteriography was performed using a new protocol with Reteplase as the fibrinolytic agent. All patients had recurrent, massive LGIB without definable source. Initial arteriography did not elicit a site of bleeding. Five units of Reteplase were administered over 1 minute into the inferior mesenteric artery, the superior mesenteric artery or both vessels sequentially. Arteriography was repeated after 5 to 10 minutes.

RESULTS

Colonic hemorrhage was induced in 89% of patients. There were no procedure-related complications.

CONCLUSIONS

Reteplase may prove safe and effective as a provocative agent, stimulating bleeding to allow localization, in patients with occult, recurrent, massive LGIB.

Nonvariceal upper gastrointestinal bleeding

Nonvariceal upper gastrointestinal bleeding (NUGB) remains a major medical problem even after advances in medical therapy with gastric acid suppression and cyclooxygenase (COX-2) inhibitors. Although the incidence of upper gastrointestinal bleeding presenting to the emergency room has slightly decreased, similar decreases in overall mortality and rebleeding rate have not been experienced over the last few decades. Many causes of upper gastrointestinal bleeding have been identified and will be reviewed. Endoscopic, radiographic and angiographic modalities continue to form the basis of the diagnosis of upper gastrointestinal bleeding with new research in the field of CT angiography to diagnose gastrointestinal bleeding. Endoscopic and angiographic treatment modalities will be highlighted, emphasizing a multi-modality treatment plan for upper gastrointestinal bleeding.

Nonlocalized lower gastrointestinal bleeding: provocative bleeding studies with intraarterial tPA, heparin, and tolazoline

PURPOSE

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.

MATERIALS AND 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.

CONCLUSION

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.

Embolization as a first approach with endoscopically unmanageable acute nonvariceal gastrointestinal hemorrhage

PURPOSE

To determine technical and clinical results of embolization of endoscopically unmanageable nonvariceal gastrointestinal hemorrhage (GIH).

MATERIALS AND METHODS

Results of 40 embolizations in 91 patients who underwent arteriography for acute nonvariceal GIH were retrospectively studied. GIH was upper, lower, or transpapillar (hemobilia, pancreatic duct bleeding). Clinical parameters and embolization data were assessed for clinical success and in-hospital survival.

RESULTS

Technical success (bleeding target devascularization) was achieved in all patients except one with upper GIH (39 [98%] of 40 patients). No bowel complications occurred. One partial liver lobe and one partial spleen infarction were noted. Five (13%) of 39 patients bled again within 3 days; all had upper GIH (P =.049). Clinical success (no rebleeding after 30 days) was achieved in 32 (82%) of 39 patients. Clinical success occurred in 13 (68%) of 19 patients with upper GIH, in 10 (91%) of 11 with lower GIH, and in all with transpapillar GIH (P =.084). Mortality rate was 28% (11 of 40 patients), equally spread over upper, lower, and transpapillar GIH (P =.87). Blood loss (hemoglobin level < 80 g/L, P =.041), use of packed cells (P =.049) and fresh frozen plasma (P =.006); shock (P =.047); and corticosteroid use (P =.036) were related to rebleeding. Shock (P =.039) and use of fresh frozen plasma (P =.003) before embolization and rebleeding (P =.012), coagulopathy (P =.007), and need for surgery (P =.03) after embolization were strongly correlated with mortality.

CONCLUSION

Embolization is an effective first approach with lower and transpapillar GIH after endoscopy; it was less effective with upper GIH.

Provocative angiography in patients with gastrointestinal hemorrhage of obscure origin

OBJECTIVE

A standard diagnostic evaluation including upper and/or lower endoscopy, tagged red blood cell scintigraphy, and visceral angiography identifies the source of GI bleeding in the majority of patients who present with acute GI hemorrhage. However, in a small group of patients the source of bleeding remains obscure; this form of GI hemorrhage is uncommon but represents a considerable diagnostic challenge. Some investigators have advocated provocation of bleeding with vasodilators, anticoagulants, and/or thrombolytics in association with tagged red blood cell scans or angiography. Unfortunately, the available literature on this topic is limited. Therefore, the purpose of this study is to report our experience with provocative GI bleeding studies.

METHODS

The radiology databases at Duke University Medical Center and the Durham Veterans Administration Medical Center were reviewed from 1994 to 1999. Any patient who received a vasodilator, anticoagulant, or thrombolytic to induce bleeding during a tagged red blood cell scan or visceral angiogram was included.

RESULTS

Seven provocative bleeding studies were performed on seven patients. All patients underwent a visceral angiogram with intra-arterial administration of tolazoline (a vasodilator), heparin (an anticoagulant), and/or urokinase (a thrombolytic). Of the seven provocative studies, only two induced angiographically identifiable bleeding. Both of these patients underwent surgical therapy. There were no complications attributed to the provocative bleeding studies.

CONCLUSIONS

These results suggest that provocative GI bleeding studies can be performed safely. However, because an active bleeding source was identified in only a small proportion of patients, we believe that further study is required to optimize patient selection and to clarify the cost-effectiveness of this approach in patients with GI hemorrhage of obscure origin.

Detection of bleeding due to small bowel cholesterol emboli using helical CT examination in gastrointestinal bleeding of obscure origin

Chronic, intermittent GI bleeding is defined as obscure when routine diagnostic examinations of the GI tract, including barium and endoscopic studies, fail to reveal the cause of bleeding. Our patient had significant bleeding and extensive evaluation including upper endoscopy, small bowel enteroscopy, enteroclysis, colonoscopy, and provocative angiography with urokinase, without the source of bleeding detected. This report describes a noninvasive novel approach using helical CT scanning with water as oral contrast and rapid injection of intravenous iodinated contrast material and thin slices obtained to diagnose the site of recurrent, obscure GI bleeding related to cholesterol crystal embolization to the small intestine.

Vasodilator provocation of occult urinary tract hemorrhage

This case demonstrates the use of vasodilators to reactivate an intermittent urinary tract hemorrhage. The site of bleeding was demonstrated and treated with subselective embolization.

Acute lower gastrointestinal bleeding

Lower gastrointestinal bleeding ranges from occult blood loss to massive hemorrhage and shock. There are many causes but diverticulitis and angiodysplasia remain the most common sources of major hemorrhage. This article emphasizes the cause and evaluation of moderate to severe acute lower gastrointestinal bleeding.