Predictive value of technetium Tc 99m-labeled red blood cell scintigraphy for positive angiogram in massive lower gastrointestinal hemorrhage

The Accuracy of Computed Tomography Angiography Compared With Technetium-99m Labelled Red Blood Cell Scintigraphy for the Diagnosis and Localization of Acute Gastrointestinal Bleeding: A Systematic Review and Meta-Analysis

Imaging tests are commonly used as an initial or early investigation for patients presenting with suspected acute gastrointestinal bleeding (AGIB). However, controversy remains regarding which of two frequently used modalities, computed tomography angiography (CTA) or technetium-99m labelled red blood cell scintigraphy (RBCS), is most accurate. This systematic review and meta-analysis was performed to compare the accuracy of CTA and RBCS for the detection and localization of AGIB. Five electronic databases were searched with additional manual searching of reference lists of relevant publications identified during the search. Two reviewers independently performed screening, data extraction and methodological assessments. Where appropriate, the bivariate model was used for meta-analysis of sensitivities and specificities for the detection of bleeding and Freeman-Tukey double-arcsine transformation used for meta-analysis of proportions of correctly localized bleeding sites. Forty-four unique primary studies were included: twenty-two investigating CTA, seventeen investigating RBCS and five investigating both modalities. Meta-analysis produced similar pooled sensitivities; 0.83 (95% CI 0.74-0.90) and 0.84 (0.68-0.92) for CTA and RBCS respectively. Pooled specificity for CTA was higher than RBCS; 0.90 (0.72-0.97) and 0.84 (0.71-0.91) respectively. However, differences were not statistically significant. CTA was superior to RBCS in correctly localizing bleeding; pooled proportions of 1.00 (0.98-1.00) and 0.90 (0.83-0.96) respectively (statistically significant difference, P < 0.001). There is no evidence that CTA and RBCS have different diagnostic performance with respect to the detection of AGIB. However, CTA is superior to RBCS in terms of correctly localising the bleeding site, supporting usage of CTA over RBCS as the first line imaging investigation.

Small Bowel Gastrointestinal Bleeding Diagnosis and Management-A Narrative Review

Background: Small bowel bleeding accounts for 5-10% of all gastrointestinal bleeding. Despite advances in imaging, endoscopy and minimally invasive therapeutic techniques, its diagnosis and treatment remains a challenge and a standardized algorithm for approaching suspected small bowel bleeding remains elusive. Furthermore, the choice of investigation is subject to timing of presentation and accessibility to investigations. The aim of this study was to construct a narrative review of recent literature surrounding the diagnosis and management of small bowel bleeding. Methods: A literature review was conducted examining the database pubmed with the following key words and Boolean operators: occult GI bleed OR mesenteric bleed OR gastrointestinal hemorrhage OR GI hemorrhage AND management. Articles were selected and reviewed based on relevance to the research topic. Where necessary, the full text was sought to further assess relevance. Results: In overt GI bleeding, CT angiography and red cell scintigraphy are both feasible and reliable diagnostic imaging modalities if standard endoscopy is negative. Red cell scintigraphy may be advantageous through detection of lower bleeding rates but it is subject to availability. Overt bleeding and a positive CT angiogram or red cell scan improves the diagnostic yield of formal angiography ± embolization. Video capsule endoscopy or double balloon endoscopy can be considered in occult GI bleeding following normal upper and lower endoscopy. Conclusions: Small bowel bleeding remains a rare but significant diagnostic and therapeutic challenge. Technological advances in diagnostics have aided evaluation but have not broadened the range of therapeutic interventions.

Independent usefulness of flow phase 99mTc-red blood cell scintigraphy in predicting the results of angiography in acute gastrointestinal bleeding

OBJECTIVE:

In acute gastrointestinal bleeding, despite positive dynamic phase ⁹⁹mTc-red blood cell scintigraphy, invasive catheter angiography (CA) is frequently negative. In this study, we investigated the value of flow phase scintigraphy in predicting extravasation on CA.

METHODS:

Institutional review board approval with a waiver of informed consent was obtained for this retrospective study. A total of 173 scintigraphy procedures performed in 145 patients with GIB between January 2013 and August 2014 were analysed. Scintigraphy had two phases: flow (1 image/s for 1 min) followed by dynamic (1 image/30 s for 1 h). Patients who underwent CA within 24 hours of positive scintigraphy were assessed. Each scintigraphy phase was randomly and independently reviewed by two nuclear medicine physicians blinded to the outcomes of the other phase and of CA.

RESULTS:

A total of 42 patients (29%) had positive scintigraphy. Of these patients, 29 underwent CA, and extravasation was seen in 6 (21%). In all, dynamic phase scintigraphy was positive. 13 of the 29 patients also had positive flow phase scintigraphy. The sensitivity, specificity, positive-predictive value, and negative-predictive value of flow phase scintigraphy for extravasation on CA were 100, 70, 46, and 100%, respectively. Specificity and positive predictive value were higher when CA was performed within 4 hours of positive flow phase scintigraphy.

CONCLUSIONS:

Negative flow phase scintigraphy can identify patients who will not benefit from CA despite positive dynamic phase scintigraphy. The likelihood of extravasation on CA is higher when performed soon after positive flow phase scintigraphy.

ADVANCES IN KNOWLEDGE:

Negative flow phase scintigraphy identifies patients who will not benefit from invasive catheter angiography despite positive results on subsequent dynamic phase scintigraphy. Increasing the delay between positive red blood cell scintigraphy and catheter angiography progressively reduces the likelihood of identifying extravasation, which is required to target embolization.

Successful Localization of the Source of Hemorrhage in Patient with Post-Whipple Surgery by 99mTc-Labelled Red Blood Cell Scintigraphy

Gastrointestinal Bleeding Scintigraphy (GIBS) of ^99mTc-labelled red blood cells is a relatively simple examination to perform, with high diagnostic accuracy and a relatively lower radiation dose. A positive scan can either suggest surgery without further investigation or can indicate angiography, a more targeted procedure. Whipple pancreatoduodenectomy is most often performed for tumors of the head of the pancreas. Pancreatoduodenectomy has 30%–40% morbidity and mortality, and while post-pancreatoduodenectomy hemorrhage is seen in less than 10% of patients, it accounts for 11%–38% mortality. The role of imaging in patients to detect relative hemodynamic stability is essential. Computed tomography angiography (CTA) shows the cause, site, and nature of bleeding, while digital subtraction angiography (DSA) has a diagnostic as well as a therapeutic role. We present a patient who presented with active gastrointestinal bleeding (GI) bleeding after undergoing a Whipple procedure, to highlight the role of GIBS in the successful localization of a bleeding site and the guidance of digital DSA in the embolization and control of the active bleeding.

Accuracy of 99mTechnetium-labeled RBC Scintigraphy and MDCT With Gastrointestinal Bleed Protocol for Detection and Localization of Source of Acute Lower Gastrointestinal Bleeding

BACKGROUND

Acute lower gastrointestinal bleeding (LGIB) is a major cause of morbidity and mortality. Multidetector row computed tomography (CT) with gastrointestinal (GI) bleed protocol is a novel diagnostic technique for detecting and localizing LGIB. Being rapid and noninvasive, it may be useful as a first-line modality to investigate cases of acute LGIB.

GOALS

To assess and compare diagnostic accuracy of (99M)Technetium (Tc)-labeled red blood cell (RBC) scintigraphy and multidetector row CT with GI bleed protocol for detection and localization of source of acute LGIB.

STUDY

Requirement of informed consent was waived for this retrospective study. Seventy-six patients had undergone either RBC scintigraphy, CT with GI bleed protocol, or both, followed by conventional angiography for evaluation of acute persistent LGIB between January 2010 and February 2014 at our institution. Accuracy of both modalities was assessed using conventional angiography as reference standard and compared using the 2-tailed, Fisher exact test. A P-value of <0.05 was considered statistically significant.

RESULTS

Fifty-one, 20, and 5 patients had undergone RBC scintigraphy only, CT with GI bleed protocol only, and both modalities, respectively. Fourteen of 25 patients in the CT group had angiographic evidence of active bleeding as compared with 32 of 56 patients in the scintigraphy group. CT with GI bleed protocol had higher accuracy (96%) than (99M)Tc-labeled RBC scintigraphy (55.4%, P<0.001).

CONCLUSIONS

CT with GI bleed protocol was more accurate in detecting and localizing the source of acute LGIB as compared with (99M)Tc-labeled RBC scintigraphy.

ACG Clinical Guideline: Management of Patients With Acute Lower Gastrointestinal Bleeding

This guideline provides recommendations for the management of patients with acute overt lower gastrointestinal bleeding. Hemodynamic status should be initially assessed with intravascular volume resuscitation started as needed. Risk stratification based on clinical parameters should be performed to help distinguish patients at high- and low-risk of adverse outcomes. Hematochezia associated with hemodynamic instability may be indicative of an upper gastrointestinal (GI) bleeding source and thus warrants an upper endoscopy. In the majority of patients, colonoscopy should be the initial diagnostic procedure and should be performed within 24 h of patient presentation after adequate colon preparation. Endoscopic hemostasis therapy should be provided to patients with high-risk endoscopic stigmata of bleeding including active bleeding, non-bleeding visible vessel, or adherent clot. The endoscopic hemostasis modality used (mechanical, thermal, injection, or combination) is most often guided by the etiology of bleeding, access to the bleeding site, and endoscopist experience with the various hemostasis modalities. Repeat colonoscopy, with endoscopic hemostasis performed if indicated, should be considered for patients with evidence of recurrent bleeding. Radiographic interventions (tagged red blood cell scintigraphy, computed tomographic angiography, and angiography) should be considered in high-risk patients with ongoing bleeding who do not respond adequately to resuscitation and who are unlikely to tolerate bowel preparation and colonoscopy. Strategies to prevent recurrent bleeding should be considered. Nonsteroidal anti-inflammatory drug use should be avoided in patients with a history of acute lower GI bleeding, particularly if secondary to diverticulosis or angioectasia. Patients with established high-risk cardiovascular disease should not stop aspirin therapy (secondary prophylaxis) in the setting of lower GI bleeding. [corrected]. The exact timing depends on the severity of bleeding, perceived adequacy of hemostasis, and the risk of a thromboembolic event. Surgery for the prevention of recurrent lower gastrointestinal bleeding should be individualized, and the source of bleeding should be carefully localized before resection.

Lower Gastrointestinal Hemorrhage

Lower gastrointestinal bleeding (LGIB) is a frequent reason for hospitalization especially in the elderly. Patients with LGIB are frequently admitted to the intensive care unit and may require transfusion of packed red blood cells and other blood products especially in the setting of coagulopathy. Colonoscopy is often performed to localize the source of bleeding and to provide therapeutic measures. LGIB may present as an acute life-threatening event or as a chronic insidious condition manifesting as iron deficiency anemia and positivity for fecal occult blood. This article discusses the presentation, diagnosis, and management of LGIB with a focus on conditions that present with acute blood loss.

Gastrointestinal Bleeding Scintigraphy in the Early 21st Century

Gastrointestinal bleeding scintigraphy performed with (99m)Tc-labeled autologous erythrocytes or historically with (99m)Tc-sulfur colloid has been a clinically useful tool since the 1970s. This article reviews the history of the techniques, the different methods of radiolabeling erythrocytes, the procedure, useful indications, diagnostic accuracy, the use of SPECT/CT and CT angiography to evaluate gastrointestinal bleeding, and Meckel diverticulum imaging. The causes of pediatric bleeding are discussed by age.

New insights to occult gastrointestinal bleeding: From pathophysiology to therapeutics

Obscure gastrointestinal bleeding is still a clinical challenge for gastroenterologists. The recent development of novel technologies for the diagnosis and treatment of different bleeding causes has allowed a better management of patients, but it also determines the need of a deeper comprehension of pathophysiology and the analysis of local expertise in order to develop a rational management algorithm. Obscure gastrointestinal bleeding can be divided in occult, when a positive occult blood fecal test is the main manifestation, and overt, when external sings of bleeding are visible. In this paper we are going to focus on overt gastrointestinal bleeding, describing the physiopathology of the most usual causes, analyzing the diagnostic procedures available, from the most classical to the novel ones, and establishing a standard algorithm which can be adapted depending on the local expertise or availability. Finally, we will review the main therapeutic options for this complex and not so uncommon clinical problem.

Lower gastrointestinal bleeding

This article examines causes of occult, moderate and severe lower gastrointestinal (GI) bleeding. The difference in the workup of stable vs unstable patients is stressed. Treatment options ranging from minimally invasive techniques to open surgery are explored.

Acute lower gastrointestinal bleeding

The annual incidence of lower gastrointestinal bleeding (LGIB) is ∼20.5 in 100,000 in the general Western population and results in 1 to 2% of hospital emergencies. When medical management and endoscopic therapy are inadequate in cases of acute LGIB, endovascular intervention can be lifesaving. In these emergent situations it is important for the interventional radiologist to be well versed in the multidisciplinary preangiographic work-up, the angiographic presentations of LGIB, and the endovascular therapeutic options. We describe a case of LGIB managed with endovascular embolization and detail the angiographic techniques used, followed by a detailed discussion of the various treatment approaches to LGIB.

[Gastrointestinal bleeding: the role of radiology]

Gastrointestinal bleeding represents a diagnostic challenge both in its acute presentation, which requires the point of bleeding to be located quickly, and in its chronic presentation, which requires repeated examinations to determine its etiology. Although the diagnosis and treatment of gastrointestinal bleeding is based on endoscopic examinations, radiological studies like computed tomography (CT) angiography for acute bleeding or CT enterography for chronic bleeding are becoming more and more common in clinical practice, even though they have not yet been included in the clinical guidelines for gastrointestinal bleeding. CT can replace angiography as the diagnostic test of choice in acute massive gastrointestinal bleeding, and CT can complement the endoscopic capsule and scintigraphy in chronic or recurrent bleeding suspected to originate in the small bowel. Angiography is currently used to complement endoscopy for the treatment of gastrointestinal bleeding.

Management of diverticular hemorrhage

Diverticular hemorrhage is the most common cause of lower gastrointestinal bleeding in Westernized cultures. Fortunately, the majority of diverticular bleeds will spontaneously resolve; however, 20% of patients will require therapeutic interventions to obtain hemostasis. The diagnostic and therapeutic options for the management of diverticular hemorrhage are discussed.

Imaging of gastrointestinal bleeding

Radiological techniques are important in evaluating patients with gastrointestinal bleeding. Scintigraphic, computed tomographic angiographic, and enterographic techniques are sensitive tools in identifying the source of bleeding and may be useful in identifying patients likely to have a benign course and in selecting patients for therapeutic intervention. Angiography plays a key role in bleeding localization, and modern embolization techniques make this a viable therapeutic option. With the refining developments in body imaging and related reconstructive techniques, it is likely that radiological interventions will play an expanding and critical role in evaluating patients with gastrointestinal hemorrhage in the future.

The role of endoscopy in the management of obscure GI bleeding

This is one of a series of statements discussing the use of GI endoscopy in common clinical situations. The Standards of Practice Committee of the American Society for Gastrointestinal Endoscopy (ASGE) prepared this text. In preparing this guideline, we performed a search of the medical literature by using PubMed. Additional references were obtained from the bibliographies of the identified articles and from recommendations of expert consultants. Guidelines for appropriate use of endoscopy are based on a critical review of the available data and expert consensus at the time the guidelines were drafted. Further controlled clinical studies may be needed to clarify aspects of this guideline. This guideline may be revised as necessary to account for changes in technology, new data, or other aspects of clinical practice. The recommendations are based on reviewed studies and are graded on the strength of the supporting evidence (Table 1).(1) The strength of individual recommendations is based both upon the aggregate evidence quality and an assessment of the anticipated benefits and harms. Weaker recommendations are indicated by phrases such as "we suggest," whereas stronger recommendations are typically stated as "we recommend." This guideline is intended to be an educational device to provide information that may assist endoscopists in providing care to patients. This guideline is not a rule and should not be construed as establishing a legal standard of care or as encouraging, advocating, requiring, or discouraging any particular treatment. Clinical decisions in any particular case involve a complex analysis of the patient's condition and available courses of action. Therefore, clinical considerations may lead an endoscopist to take a course of action that varies from these guidelines.

Acute lower GI bleeding for the acute care surgeon: current diagnosis and management

Lower gastrointestinal bleeding is a common cause for hospital admission that results in significant morbidity and mortality. After initial resuscitation of the patient, the diagnosis and treatment of lower gastrointestinal bleeding remains a challenge for acute care surgeons. Identifying the source of bleeding can be difficult since many patients bleed intermittently or stop bleeding spontaneously. It is therefore important for the acute care surgeon to be familiar with the different diagnostic and therapeutic modalities and their advantages and disadvantages in order to guide the management of the acutely bleeding patient. This review summarizes the current methods available for the diagnosis and treatment of acute lower gastrointestinal bleeding and proposes an algorithm for the management of these patients.

The evaluation and management of obscure and occult gastrointestinal bleeding

Gastrointestinal (GI) bleeding is a common clinical presentation increasing in an aging population, frequently requiring hospitalization and emergent intervention, with significant morbidity, mortality, and costs. It may manifest overtly as hematemesis, melena, or hematochezia, or as an asymptomatic occult bleed. Management typically involves an esophagogastroduodenoscopy or a colonoscopy; these in combination sometimes do not identify a source of bleeding, with the source remaining obscure. Further work up to identify an obscure source frequently requires radiologically detecting the leakage of an intravascular tracer (using tagged red blood cells or angiography) with brisk bleeding or in other cases CT enterography (CTE) to detect bowel wall changes consistent with a bleeding source. Recent advances including capsule endoscopy, CTE, and double-balloon endoscopy have helped to identify bleeding sources beyond the reach of conventional endoscopy. Clinical decision-making about their use is complex and evolving. Knowing their relative merits and weaknesses including yield, contraindications, complications, and cost is essential in coming up with an appropriate management plan. This review covers the rationale for clinical management of obscure sources of GI bleeding, mentioning the approach to and the yield of conventional methods, with an emphasis on the recent advances mentioned above.

Efficacy of transarterial embolization as definitive treatment in lower gastrointestinal bleeding

Transarterial catheter embolization (TAE) is integral in the management of lower gastrointestinal bleeding (BLGIT). The efficacy of superselective embolization has reduced the need for emergent surgical resection as a treatment modality.

OBJECTIVE

To determine the outcomes of TAE in the management of BLGIT in terms of efficacy rates, recurrent bleeding rates and long term results without the need for surgical intervention.

METHOD

Patients who underwent TAE for BLGIT between September 2000 and May 2006 were analysed. Data were extracted from the records for analysis.

RESULTS

Sixty-eight patients with a mean age of 76 years and equal gender distribution were analysed. Sixty-nine per cent presented with haematochezia, 40% with malena. Sixty-three patients had a prior RBC scan performed, all of which were positive. Colonoscopy was attempted in 18 patients of which four managed to localize the bleeding site. Embolization was performed in these patients using mainly polyvinyl alcohol particles and/or microcoils. The morbidity rate was 21%, comprising mainly fever and nonspecific abdominal pain with only four ischaemic complications and one report of colonic infarction. Early recurrent bleeding occurred in six patients. Three were treated with repeat embolization and two required surgery. There were no mortalities. After a mean follow-up of 12 months, 12 (17.6%) patients developed further episodes of BLGIT, necessitating further intervention.

CONCLUSION

Transarterial catheter embolization is effective and safe in the acute management of BLGIT and reduces the need for further definitive surgery in a majority of patients.

Pediatric Gastrointestinal Nuclear Medicine

General localization of gastrointestinal bleeding through the use of labeled red blood cells may be performed in children, or (99m)Tc-pertechnetate may be used if a Meckel's diverticulum is suspected. As in adults, cholecystitis and biliary leak may be assessed in children via (99m)Tc-IDA derivatives. Gastroesophageal reflux can be evaluated by oral consumption of the child's usual diet labeled with (99m)Tc sulfur colloid. For the scintigraphic determination of pulmonary aspiration, a relatively high concentration of tracer within a drop of liquid is placed beneath the child's tongue followed by dynamic imaging of the respiratory tract. Colonic transit scintigraphy can aid in the identification and therapeutic decision-making in patients with functional fecal retention, the most common cause of chronic constipation in children. (18)F-DOPA positron emission tomography is useful for classifying pancreatic involvement in infantile hyperinsulinism as focal or diffuse, thereby differentiating between patients who should receive curative focal pancreatic resection versus those who should receive medical management. Assessment of protein-losing enteropathy can be conducted scintigraphically and, compared with fecal alpha-1 antitrypsin collection, the scintigraphic method can detect esophageal and gastric protein loss. Also, scintigraphic quantification of protein loss can be performed without the requirement for fecal collection. Intestinal inflammation in children with inflammatory bowel disease can be evaluated using (99m)Tc white blood cells. The scintigraphic method is safe, accurate, well-tolerated by children and complementary to endoscopy in most patients.

Implications of negative technetium 99m-labeled red blood cell scintigraphy in patients presenting with lower gastrointestinal bleeding

BACKGROUND

Lower gastrointestinal (GI) bleeding frequently recurs after negative technetium 99m-labeled red blood cell (RBC) scintigraphy.

METHODS

Between July 1, 1999 and July 31, 2005, 84 negative (99m)Tc-labeled RBC scintigrams were obtained for acute lower GI bleeding. Medical records were abstracted for age, gender, prior history of lower GI hemorrhage, length of hospitalization, initial hematocrit (Hct) and Hct nadir, transfusion requirements, cause of bleeding, use of anticoagulants and/or antiplatelet medications, and rebleeding episodes.

RESULTS

The overall rate of rebleeding was 27% (n = 23). There were no significant associations between any of the patient variables investigated and rebleeding.

CONCLUSIONS

Despite negative (99m)Tc-labeled RBC scintigraphy, more than 25% of patients experience recurrent lower GI bleeding. Patient age, bleeding source, use of anticoagulant/antiplatelet medications, length of stay, admission Hct, Hct nadir, transfusion requirements, and gender are not predictive of the patients who will rebleed.

Clinical variables associated with positive angiographic localization of lower gastrointestinal bleeding

BACKGROUND

Localizing the source of severe lower gastrointestinal (GI) bleeding is often difficult but is important to plan the extent of colonic resection. The purpose of the present paper was to audit the Auckland Hospital experience of selective angiography, in localizing lower GI bleeding.

METHODS

Patients admitted to Auckland Hospital with rectal bleeding and who subsequently had angiography were evaluated by reviewing their clinical notes and radiological results during a 7-year period (1997-2003). Data collected included demographic details, haemodynamic parameters, change in haemoglobin level, requirement of blood transfusion within 24 h before the procedure, site of the bleeding and pathology.

RESULTS

The notes of 88 patients (male, n = 51; median age 69 years, range 8-99 years) were available for review and analysis. The site of bleeding was localized in 38 (51%); 30 of them had bleeding in the right colon or small bowel and eight in the left colon. Positive localization correlated with: haemodynamic instability P < 0.0001; drop in haemoglobin level of > or =50 from previous admission (P = 0.02); transfusion requirement of > or =5 units of blood within 24 h (P < 0.0001). Logistic regression analysis showed transfusion requirement of > or =5 units to achieve haemodynamic stability to be the most powerful predictor of accurate localization (odds ratio, 40).

CONCLUSION

Catheter angiography for acute lower GI bleeding will successfully localize a point of bleeding in approximately 50% of patients. The most useful clinical indicator for positive angiography was haemodynamic instability particularly in those who require transfusion of > or =5 units of blood to achieve haemodynamic stability.

Obscure gastrointestinal bleeding

Obscure GI bleeding is a relatively common problem facing internists, gastroenterologists, and surgeons in a typical clinical practice. The etiology is occasionally suggested by the patient's age, history, and medications. Management is complicated and typically requires a team-oriented approach, with input from the internist, gastroenterologist, radiologist, and surgeon alike. SBFT and enteroclysis seem to have a limited role, unless there is a high suspicion of a small bowel mass lesion or Crohn's disease. Scintigraphy may be performed in patients with active bleeding in whom endoscopy has failed oris contraindicated. Angiography may be used in patients with an early positive nuclear imaging or failed endoscopic therapy. Provocative angiography probably has a lower diagnostic yield than previously reported, and should be performed only in experienced centers. Helical CT is a new and potentially important option in patients with obscure bleeding, but is currently considered experimental. All patients with obscure GI bleeding should undergo repeat upper endoscopy and perhaps colonoscopy to rule out missed lesions. SBE seems to be complementary to capsule endoscopy, and it is unknown whether this should be performed before capsule endoscopy or only if capsule endoscopy yields a positive proximal small bowel finding. Double balloon enteroscopy seems promising, but the technique requires further study. Surgery should be reserved for patients who have a positive capsule endoscopy requiring surgical therapy or patients who have persistent GI bleeding requiring recurrent blood transfusions in whom all other modalities have failed. Treatment for vascularectasias, the most common cause of obscure GI bleeding, is currently inadequate,and typically requires a combination of multiple management approaches.

Lower GI bleeding: epidemiology and diagnosis

Lower gastrointestinal bleeding is one of the most common gastrointestinal indications for hospital admission, particularly in the elderly. Diverticulosis accounts for up to 50% of cases, followed by ischemic colitis and anorectal lesions. Though most patients stop bleeding spontaneously and have favorable outcomes, long-term recurrence is a substantial problem for patients with bleeding from diverticulosis and angiodysplasia. The management of LGIB is challenging because of the diverse range of bleeding sources, the large extent of bowel involved, the intermittent nature of bleeding, and the various complicated and often invasive investigative modalities. Advances in endoscopic technology have brought colonoscopy to the forefront of the management of LGIB. However, many questions remained to be answered about its usefulness in routine clinical practice. More randomized controlled trials comparing available diagnostic strategies for LGIB are needed.

Does hemodynamic instability predict positive technetium-labeled red blood cell scintigraphy in patients with acute lower gastrointestinal bleeding? A review of 50 patients

PURPOSE

Technetium-99m-labeled red blood cell scintigraphy, commonly used in the evaluation of acute lower gastrointestinal hemorrhage, often fails to demonstrate a source of bleeding. It would be helpful to characterize a subset of patients more likely to have a positive scan. This study was undertaken to determine whether hemodynamic instability can predict tagged red blood cell scan positivity.

METHODS

The records of 50 consecutive patients who underwent tagged red blood cell scanning for the evaluation of acute lower gastrointestinal bleeding were reviewed retrospectively.

RESULTS

Patients presenting with a heart rate >100 beats per minute or a systolic blood pressure <100 mmHg up to 24 hours before undergoing tagged red blood cell scanning were considered hemodynamically unstable. Thirteen of 21 unstable patients (62 percent) had positive scans, whereas only 6 of 29 stable patients (21 percent) had positive scintigraphy (odds ratio, 6; 95 percent confidence interval, 1.79-22.1).

CONCLUSIONS

Hemodynamic instability in the setting of acute lower gastrointestinal bleeding may be a predictor of positive tagged red blood cell scanning. Incorporating this into the diagnostic algorithm used to evaluate patients with acute lower gastrointestinal bleeding may allow physicians to reserve red blood cell scintigraphy for patients who have demonstrated transient hemodynamic compromise.

The yield of bleeding scans in acute lower gastrointestinal hemorrhage

GOALS/BACKGROUND

Previous studies have demonstrated low yield and conflicting results as to the ability of technetium-99m labeled red blood cell (TRBC) scintigraphy to accurately localize the site of bleeding in acute lower gastrointestinal hemorrhage. Our objective was to evaluate the accuracy of TRBC scintigraphy in clinical day-to-day practice at our institution and to determine predictors of a positive test.

METHODS

A retrospective medical records review of all patients who underwent TRBC scintigraphy over a 5-year period was conducted at a single academic medical center. The site of bleeding found on TRBC scintigraphy was correlated with the endoscopic, angiographic, surgical, and pathologic findings in each patient.

RESULTS

A total of 127 scans were performed in 115 patients. Forty-nine scans were positive (39%) and 78 were negative (61%). Forty-two patients had further evaluation after a positive scan, and the bleeding site was confirmed to be accurate in 20 of 42 patients (48%). A contradictory bleeding site was found in 5 of 49 positive scans (10%). Patients transfused greater than 2 units of packed red blood cells within 24 hours preceding the TRBC scan were twice as likely to have a positive scan (64%) than those transfused 2 units or less (32%) (P = 0.002). Multivariate analysis demonstrated that the number of units of blood transfused within 24 hours prior to the TRBC scan and the lowest recorded hematocrit were significantly different between patients with positive and negative scans. There was no difference in the rate of endoscopy between patients with a positive or negative scan result.

CONCLUSIONS

TRBC scintigraphy has a relatively low yield in the evaluation of acute lower gastrointestinal bleeding. Objective selection criteria such as number of units of packed red blood cells transfused prior to obtaining the scan may increase the overall yield.

Embolization for major lower gastrointestinal haemorrhage: five-year experience

The management of major lower gastrointestinal haemorrhage has changed dramatically in the last 15 years. Innovations in coaxial catheter technology have allowed the interventional radiologist to reach the small peripheral mesenteric arteries and perform superselective embolization with a variety of agents. The present large series represents the 5-year experience of this technique at the Alfred Hospital, Melbourne, in a patient cohort with a high number of comorbidities. Technical success was achieved in 96% of cases. The clinical symptoms of mesenteric ischaemia developed in four patients after embolization and were managed conservatively in two. The procedure-related mortality was low when compared with the published complication rates for emergency surgery, in this clinical setting.

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Colonic diverticulosis and diverticular hemorrhage

Colonic diverticulosis predisposes individuals to lower gastrointestinal hemorrhage in up to 5% of cases. These sac-like protrusions are pseudodiverticula and arise due to a combination of anatomic, dietary, motility, and structural influences. In the setting of acute hemorrhage, patient stabilization takes priority, followed closely by maneuvers aimed at localizing and controlling blood loss. Through the use of an arsenal of tools including colonoscopy, angiography, and nuclear scintigraphy, most diverticular bleeds can be localized and subsequently controlled. When persistent and not controlled by colonoscopic or angiographic means, expeditious surgical resection serves as definitive therapy.

Obscure gastrointestinal bleeding

This is one of a series of statements discussing the utilization of GI endoscopy in common clinical situations. The Standards of Practice Committee of the American Society for Gastrointestinal Endoscopy prepared this text. In preparing this guideline, a MEDLINE literature search was performed, and additional references were obtained from the bibliographies of the identified articles and from recommendations of expert consultants. When little or no data exist from well-designed prospective trials, emphasis is given to results from large series and reports from recognized experts. Guidelines for appropriate utilization of endoscopy are based on a critical review of the available data and expert consensus. Further controlled clinical studies are needed to clarify aspects of this statement, and revision may be necessary as new data appear. Clinical consideration may justify a course of action at variance to these recommendations.

Delayed 99mTc-labeled erythrocyte scintigraphy in patients with lower gastrointestinal tract hemorrhage: effect of positive findings on clinical management

RATIONALE AND OBJECTIVES

This study was performed to determine whether the results of delayed technetium 99m (99mTc)-labeled erythrocyte scintigraphy for lower gastrointestinal tract hemorrhage resulted in different clinical management and outcome from that in cases in which the results of initial scintigraphy were negative or equivocal.

MATERIALS AND METHODS

The authors retrospectively reviewed all 398 99mTc-labeled erythrocyte scintigraphic studies obtained emergently for lower gastrointestinal tract hemorrhage at their institution between January 1, 1994, and December 7, 2001. Of 67 patients who underwent delayed studies, 37 had positive findings (average delay, 18.4 hours; range, 6-25 hours) and 30 had negative findings (average delay, 20.1 hours; range, 8-26 hours). Clinical management and outcome were compared between these two groups with respect to duration of hospitalization, volume of blood transfusion, mortality, and the percentage who were treated conservatively or referred for angiography, endoscopy, and/or surgery.

RESULTS

Patients with positive delayed studies were referred more frequently for angiography than those with negative studies (35% vs 0%, P < .01). There were no significant differences between patients with positive findings and patients with negative findings with respect to mortality (8% vs 0%, P < .32), transfusion requirements (5.6 vs 3.2 units, P < .20), hospitalization (9.5 vs 6.1 days, P < .11), the percentage treated conservatively (35% vs 37%, P < .90), or the percentages referred for endoscopy (49% vs 60%, P < .50) or for surgery (24% vs 17%, P < .64).

CONCLUSION

Positive findings at delayed scintigraphy resulted in increased referrals for angiography but had no other effect on clinical course or outcome of lower gastrointestinal tract hemorrhage.

Retrospective study of the utility of nuclear scintigraphic-labelled red cell scanning for lower gastrointestinal bleeding

BACKGROUND

The aim of the present study was to evaluate the utility of nuclear scintigraphic-labelled red cell scanning in the management of bleeding in patients with acute lower gastrointestinal haemorrhage (GIH) who require surgery.

METHODS

A prospective database was used to source data on all patients with lower GIH who underwent technetium-99m (99mTc)-labelled red cell scanning over a 10-year period. A subgroup was identified from cross-reference with the medical records identifying only those patients who continued to bleed and subsequently required laparotomy for further detailed retrospective study. One key question was asked: did the labelled red cell scan influence the type of operation performed by the operating surgeon?

RESULTS

The study identified 249 patients who underwent 287 labelled red cell scans for GIH. Forty patients (16%) underwent laparotomy for ongoing bleeding; 28/40 (70%) of the red cell scans were positive for bleeding. Six patients (15%) died postoperatively, none because of continued bleeding. The 99mTc-labelled red cell scan was deemed to have been unhelpful in 22 (55%) cases. Twelve of the 22 scans were negative and 10 of the 22 scans were positive but were ignored by the surgeon. The 99mTc-labelled red cell scan influenced the choice of operation in 18 out of 40 patients (45% of the operated group but only 7.2% of the total scanned group). Of these, 15 patients underwent colonic resection and three patients underwent small bowel resection.

CONCLUSION

The present study demonstrates that labelled red cell scanning has only a small role to play in managing lower GIH. The 99mTc-labelled red cell scanning should be used much more selectively. Its use should be limited to patients who continue to bleed after conservative management; it may allow these patients to be effectively treated by segmental bowel resection. Its most critical role, however, is probably to prevent suspected small bowel bleeding from being missed at operation.

The clinical utility of nuclear medicine imaging for the detection of occult gastrointestinal haemorrhage

Acute gastrointestinal bleeding is often intermittent and the bleeding source may be difficult to locate, resulting in delay of potentially life-saving treatment. The aim of this study was to determine the clinical utility of 99mTc labelled red blood cell imaging and [99mTc]pertechnetate (Meckel's scan) imaging in a series of 137 patients admitted over a 5 year period to hospital for management of acute gastrointestinal bleeding. Of the 137 patients, 70 had positive 99mTc red blood cell studies. Eleven of 24 patients who had imaging performed beyond 3 h had positive scans that would otherwise have been missed. Only 47 patients had a definite final diagnosis at the time of hospital discharge, of which six were negative on 99mTc red blood cell imaging. The correct site of bleeding was localized in seven of 21 patients with foregut bleeding, and 15 of 20 patients with colonic bleeding. Endoscopy yielded a diagnosis in 13 of the 47 patients (28%). Eleven patients had Meckel's scans but all were negative. Angiography was diagnostic in one of 17 patients studied. 99mTc red blood cell imaging is a useful test in the management of acute gastrointestinal bleeding. Imaging beyond 3 h may further improve the bleeding detection rate. This test, however, may be an unreliable means of localization of bleeding, particularly in the foregut.

Investigative modalities for massive lower gastrointestinal bleeding

The objective of this study was to evaluate the efficacy of various diagnostic modalities in the assessment of patients with massive lower gastrointestinal bleeding. The charts of all patients admitted to a McGill University affiliated teaching hospital with the diagnosis of lower gastrointestinal bleeding over a 25-year period were reviewed. There were 136 patients who underwent 202 admissions. The information documented included demographics on age, gender, co-morbid disease, prescribed medications, requirements for blood transfusions, orthostatic change in blood pressure, acute drop in hematocrit (to <30%), and exclusion of upper gastrointestinal bleeding. Among the 202 admitted patients there were 116 men and 86 women), with an average age of 70 years (range 16-95 years). At least one significant medical disease was found in 93% of these patients; and 20% were on aspirin and 5% on anticoagulants at the time of diagnosis. Rigid or flexible sigmoidoscopy was performed in 68 and 18 patients, respectively, with a definitive diagnosis made in 2.9% and 11.0%, respectively. Colonoscopy was performed in 152 cases, 20 of which were incomplete; a specific diagnosis was made for 59 admissions (45%). A red blood cell or colloid scan was performed on 53 patients, with extravasation noted in 13 (24.5%); a localized site of bleeding was identified in 9 cases (17%). Angiography was performed on 31 patients with bleeding sites localized in 6 (19%). Barium enemas were completed in 85 of 92 patients, and the presumptive cause of bleeding was identified in 72% of those with a complete examination. The most common causes identified were diverticulosis in 52 patients and angiodysplasia in 14. The cause of bleeding was not detected in 48 (35%). Bleeding stopped in most patients spontaneously, with only 7 requiring operation. The average number of units transfused was 3 (range 0-26). Scintigraphy and angiography were less efficacious than colonoscopy for localizing the site and etiology of the bleeding. Despite the combination of investigative modalities, a definitive diagnosis was not made in 35% of the admitted patients. The need for operative intervention in our study was lower than in most previous reports.

Gastrointestinal bleeding in the elderly

Gastrointestinal bleeding in elderly individuals is a frequent cause of consultation with a physician and of hospital admissions. Co-morbidity and greater medication use in this steadily growing patient group influence the clinical course and adversely affect outcome. Clinical presentation is often predictable and guides subsequent patient management. Due to a surprising lack of prospective controlled data in the area of gastrointestinal bleeding, the selection of diagnostic and therapeutic manoeuvres often depends more on local expertise and availability than on an algorithmic approach. Advances in endoscopic, medical, radiological and surgical treatment modalities offer promising new diagnostic and therapeutic tools, particularly in concerted applications. Outcome studies on the appropriate sequence and linking of these modalities are urgently needed. This chapter will address clinical presentation, aetiology, diagnosis and treatment of both upper and lower gastrointestinal bleeding in the elderly.

Colonoscopic management of lower gastrointestinal hemorrhage

Lower gastrointestinal bleeding is a common reason for hospitalization, especially among the elderly. Unlike that of upper gastrointestinal bleeding, the diagnostic and therapeutic approach to individuals with lower gastrointestinal bleeding is not well standardized. Recent reports indicate that early colonoscopy may be the best strategy to improve outcomes and reduce costs. However, good prospective, controlled data on the role of colonoscopy in the management of lower gastrointestinal bleeding are still required. Colonoscopy can establish a definite or probable diagnosis in greater than 80% of individuals with lower gastrointestinal bleeding. Based on the best available evidence, it appears that clinical and colonoscopic data may be combined in an effort to predict outcome and suggest optimal length of stay. It also appears that therapeutic colonoscopy can arrest or prevent bleeding in certain high-risk patients, offering the opportunity to change the natural history of the bleed.

[Role of early colonoscopy in severe acute lower gastrointestinal bleeding]

BACKGROUND

Severe acute lower gastrointestinal bleeding (SALGIB) accounts for 15% of cases of acute lower gastrointestinal bleeding (ALGIB). The incidence increases with age and comorbidity. Identification of the origin of bleeding may be difficult. Colonoscopy has been proposed as the primary investigative tool.

AIM

To assess the role of early colonoscopy as the primary method of evaluation in patients with SALGIB.

PATIENTS AND METHOD

Retrospective study based on a guideline for clinical practice approved in our institution. The study included 50 patients with SALGIB admitted to our gastrointestinal bleeding unit between January 1998 and April 2000. SALGIB was suspected when patients fulfilled two or more of the following criteria: 1) significant hemodynamic compromise, 2) decrease in hemoglobin 2 g/dl, and 3) transfusion requirement >= 2 blood units. Early colonoscopy was performed within 24 hours of onset of bleeding. An accurate endoscopic diagnosis was established if a lesion with active bleeding, visible non-hemorrhagic vessel or adherent red clot was identified. A presumptive diagnosis was made when hematochezia or fresh blood localized in a colonic segment, associated with a single, potentially hemorrhagic lesion, was observed and when the results of esophagogastroduodenoscopy were negative. Colonoscopy, esophagogastroduodenoscopy, barium studies, nuclear scan and angiography were performed.

RESULTS

Two hundred twenty-two patients were admitted for ALGIB. Fifty patients(22%) fulfilled the SALGIB criteria. The male/female ratio was 1:1. Definitive diagnosis was accurate in 20 patients. The most frequent cause was angiodysplasia (6 patients) and rectal ulcer (6 patients). Eighteen patients had a presumptive diagnosis; of these 14 had diverticulosis. In 12 patients, no cause was identified. Colonoscopy was performed in 45 patients, of which 32 were performed early and 13 electively. Accurate endoscopic diagnosis was more frequently established with early colonoscopy than with elective colonoscopy (15 [47%] vs 2 [15%], p < 0.05). The results of urgent nuclear scans contributed to accurate diagnosis in 5 out of the 10 patients in whom this technique was performed. Angiography was performed in 2 patients. Endoscopic therapy was attempted in 4 patients, all during early colonoscopy. Ten patients (20%) underwent surgery and 3 patients (6%) died.

CONCLUSIONS

In 22% of patients with ALGIB admitted to our hospital bleeding was severe. Colonoscopy is the diagnostic tool of choice. When performed within 24 hours of hospital admission, this technique provides more accurate diagnosis than when performed electively.

Lower intestinal bleeding

Lower gastrointestinal tract bleeding is a frequent cause of physician consultations and hospital admissions. Clinical presentation is predictable and significantly influences subsequent patient management. Controversy surrounding diagnosis and treatment of lower gastrointestinal bleeding results from a surprising lack of prospective controlled data. Thus, selection of diagnostic and therapeutic manoeuvres often depends more on local expertise and availability than on an algorithm approach. Advances in endoscopic, radiological and surgical equipment and techniques offer promising new diagnostic and therapeutic modalities, particularly in concerted applications. Outcome studies on the appropriate sequence and linking of these modalities are urgently needed. The present chapter will address clinical presentation, aetiology, diagnosis and treatment of lower gastrointestinal tract bleeding.

Acute gastrointestinal bleeding

Acute gastrointestinal bleeding is a significant worldwide medical problem. Despite modern measures for diagnosis and treatment, morbidity and mortality rates associated with gastrointestinal bleeding remain largely unchanged. Aggressive medical resuscitation while initiating an evaluation to localize the site of blood loss remains the key to successful management of acute gastrointestinal bleeding. A multidisciplinary approach with early involvement of a gastroenterologist, surgeon, and radiologist can be extremely helpful in the management of these patients. With the logical and direct approach to the evaluation of patients with gastrointestinal bleeding described in this article, most episodes can be managed successfully.

Surgical management of gastrointestinal bleeding

Severe gastrointestinal bleeding has historically been a clinical problem primarily under the purview of the general surgeon. Diagnostic advances made as the result of newer technologies, such as fiberoptic and video endoscopy, selective visceral arteriography, and nuclear scintigraphy, have permitted more accurate and targeted operations. More importantly, they have led to safe, effective nonoperative therapeutic interventions that have obviated the need for surgery in many patients. Today, most gastrointestinal bleeding episodes are initially managed by endoscopic or angiographic control measures. Such interventions are often definitive in obtaining hemostasis. Even temporary cessation or attenuation of massive bleeding in an unstable patient permits a safer, more controlled operative procedure by allowing an adequate period of preoperative resuscitation. Despite the less frequent need for surgical intervention, traditional operative approaches, such as suture ligation, lesion or organ excision, vagotomy, portasystemic anastomosis, and devascularization procedures, continue to be life-saving in many instances. The proliferation of laparoscopic surgery has fostered the application of minimally invasive techniques to highly selected patients with gastrointestinal bleeding. Intraoperative endoscopy has greatly facilitated the accuracy of laparoscopic surgery by endoscopic localization of bleeding lesions requiring excision. It is anticipated that the evolving technologies pertinent to the diagnosis and management of gastrointestinal bleeding will continue to promote collaboration and cooperation between gastroenterologists, radiologists, and surgeons.