Correlation of CT Angiography and 99mTechnetium-Labeled Red Blood Cell Scintigraphy to Catheter Angiography for Lower Gastrointestinal Bleeding: A Single-Institution Experience

Prediction of gastrointestinal active arterial extravasation on computed tomographic angiography using multivariate clinical modeling

AIMS

To evaluate the ability of logistic regression and machine learning methods to predict active arterial extravasation on computed tomographic angiography (CTA) in patients with acute gastrointestinal hemorrhage using clinical variables obtained prior to image acquisition.

MATERIALS AND METHODS

CT angiograms performed for the indication of gastrointestinal bleeding at a single institution were labeled retrospectively for the presence of arterial extravasation. Positive and negative cases were matched for age, gender, time period, and site using Propensity Score Matching. Clinical variables were collected including recent history of gastrointestinal bleeding, comorbidities, laboratory values, and vitals. Data were partitioned into training and testing datasets based on the hospital site. Logistic regression, XGBoost, Random Forest, and Support Vector Machine classifiers were trained and five-fold internal cross-validation was performed. The models were validated and evaluated with the area under the receiver operating characteristic curve.

RESULTS

Two-hundred and thirty-one CTA studies with arterial gastrointestinal extravasation were 1:1 matched with 231 negative studies (N=462). After data preprocessing, 389 patients and 36 features were included in model development and analysis. Two hundred and fifty-five patients (65.6%) were selected for the training dataset. Validation was performed on the remaining 134 patients (34.4%); the area under the receiver operating characteristic curve for the logistic regression, XGBoost, Random Forest, and Support Vector Machine classifiers was 0.82, 0.68, 0.54, and 0.78, respectively.

CONCLUSION

Logistic regression and machine learning models can accurately predict presence of active arterial extravasation on CTA in patients with acute gastrointestinal bleeding using clinical variables.

Emergency medicine updates: Lower gastrointestinal bleeding

INTRODUCTION

Lower gastrointestinal bleeding (LGIB) is a condition commonly seen in the emergency department. Therefore, it is important for emergency medicine clinicians to be aware of the current evidence regarding the diagnosis and management of this disease.

OBJECTIVE

This paper evaluates key evidence-based updates concerning LGIB for the emergency clinician.

DISCUSSION

LGIB is most commonly due to diverticulosis or anorectal disease, though there are a variety of etiologies. The majority of cases resolve spontaneously, but patients can have severe bleeding resulting in hemodynamic instability. Initial evaluation should focus on patient hemodynamics, the severity of bleeding, and differentiating upper gastrointestinal bleeding from LGIB. Factors associated with LGIB include prior history of LGIB, age over 50 years, and presence of blood clots per rectum. Computed tomography angiography is the imaging modality of choice in those with severe bleeding to diagnose the source of bleeding and guide management when embolization is indicated. Among stable patients without severe bleeding, colonoscopy is the recommended modality for diagnosis and management. A transfusion threshold of 7 g/dL hemoglobin is recommended based on recent data and guidelines (8 g/dL in those with myocardial ischemia), though patients with severe bleeding and hemodynamic instability should undergo emergent transfusion. Anticoagulation reversal may be necessary. If bleeding does not resolve, embolization or endoscopic therapies are necessary. There are several risk scores that can predict the risk of adverse outcomes; however, these scores should not replace clinical judgment in determining patient disposition.

CONCLUSIONS

An understanding of literature updates can improve the care of patients with LGIB.

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.

Management of Patients With Acute Lower Gastrointestinal Bleeding: An Updated ACG Guideline

Acute lower gastrointestinal bleeding (LGIB) is a common reason for hospitalization in the United States and is associated with significant utilization of hospital resources, as well as considerable morbidity and mortality. These revised guidelines implement the Grading of Recommendations, Assessment, Development, and Evaluation methodology to propose recommendations for the use of risk stratification tools, thresholds for red blood cell transfusion, reversal agents for patients on anticoagulants, diagnostic testing including colonoscopy and computed tomography angiography (CTA), endoscopic therapeutic options, and management of antithrombotic medications after hospital discharge. Important changes since the previous iteration of this guideline include recommendations for the use of risk stratification tools to identify patients with LGIB at low risk of a hospital-based intervention, the role for reversal agents in patients with life-threatening LGIB on vitamin K antagonists and direct oral anticoagulants, the increasing role for CTA in patients with severe LGIB, and the management of patients who have a positive CTA. We recommend that most patients requiring inpatient colonoscopy undergo a nonurgent colonoscopy because performing an urgent colonoscopy within 24 hours of presentation has not been shown to improve important clinical outcomes such as rebleeding. Finally, we provide updated recommendations regarding resumption of antiplatelet and anticoagulant medications after cessation of LGIB.

Oro-pharyngo-esophageal radionuclide scintigraphy predicts aspiration pneumonia risk and associated survival in post-irradiated nasopharyngeal carcinoma patients

OBJECTIVE

To demonstrate that oro-pharyngo-esophageal radionuclide scintigraphy (OPERS) not only detects tracheobronchial aspiration after swallowing, but also quantifies the amount of aspiration and subsequent clearance.

METHODS

Data collected between 2014 and 2019 were reviewed for aspiration pneumonia at 12 and 24-months after OPERS. The predictive value for aspiration pneumonia on flexible endoscopic evaluation of swallowing (FEES), videofluoroscopic swallowing study (VFSS), and OPERS, and the overall survival of patients with or without aspiration were determined.

RESULTS

Thirty-seven patients treated with radiotherapy for nasopharyngeal carcinoma (NPC) were reviewed. The incidence of aspiration detected on FEES, VFSS, and OPERS was 78.4%, 66.7%, and 44.4%, respectively. Using VFSS as a gold standard, the sensitivity and specificity of OPERS for aspiration was 73.7% and 100%. The positive and negative predictive values for aspiration were 100% and 66.7%, respectively, with an overall accuracy of 82.8%. A history of aspiration pneumonia was one factor associated with a higher chance of subsequent aspiration pneumonia within 12 months (odds ratio: 15.5, 95% CI 1.67-145.8, p < .05) and 24 months (odds ratio: 23.8, 95% CI 3.69-152.89, p < .01) of the swallowing assessment. Aspiration detected by OPERS was a significant risk factor for future aspiration pneumonia at 12 and 24 months respectively. Significantly, better survival was associated with an absence of aspiration on OPERS only, but not on FEES or VFSS.

CONCLUSION

OPERS predicts the safety of swallowing, the incidence of subsequent aspiration pneumonia, and the survival prognosis in post-irradiated NPC dysphagia patients.

LEVEL OF EVIDENCE

3.

Diagnosis and management of acute lower gastrointestinal bleeding: European Society of Gastrointestinal Endoscopy (ESGE) Guideline

1: ESGE recommends that the initial assessment of patients presenting with acute lower gastrointestinal bleeding should include: a history of co-morbidities and medications that promote bleeding; hemodynamic parameters; physical examination (including digital rectal examination); and laboratory markers. A risk score can be used to aid, but should not replace, clinician judgment.Strong recommendation, low quality evidence. 2 : ESGE recommends that, in patients presenting with a self-limited bleed and no adverse clinical features, an Oakland score of ≤ 8 points can be used to guide the clinician decision to discharge the patient for outpatient investigation.Strong recommendation, moderate quality evidence. 3 : ESGE recommends, in hemodynamically stable patients with acute lower gastrointestinal bleeding and no history of cardiovascular disease, a restrictive red blood cell transfusion strategy, with a hemoglobin threshold of ≤ 7 g/dL prompting red blood cell transfusion. A post-transfusion target hemoglobin concentration of 7-9 g/dL is desirable.Strong recommendation, low quality evidence. 4 : ESGE recommends, in hemodynamically stable patients with acute lower gastrointestinal bleeding and a history of acute or chronic cardiovascular disease, a more liberal red blood cell transfusion strategy, with a hemoglobin threshold of ≤ 8 g/dL prompting red blood cell transfusion. A post-transfusion target hemoglobin concentration of ≥ 10 g/dL is desirable.Strong recommendation, low quality evidence. 5: ESGE recommends that, in patients with major acute lower gastrointestinal bleeding, colonoscopy should be performed sometime during their hospital stay because there is no high quality evidence that early colonoscopy influences patient outcomes.Strong recommendation, low quality of evidence. 6 : ESGE recommends that patients with hemodynamic instability and suspected ongoing bleeding undergo computed tomography angiography before endoscopic or radiologic treatment to locate the site of bleeding.Strong recommendation, low quality evidence. 7 : ESGE recommends withholding vitamin K antagonists in patients with major lower gastrointestinal bleeding and correcting their coagulopathy according to the severity of bleeding and their thrombotic risk. In patients with hemodynamic instability, we recommend administering intravenous vitamin K and four-factor prothrombin complex concentrate (PCC), or fresh frozen plasma if PCC is not available.Strong recommendation, low quality evidence. 8 : ESGE recommends temporarily withholding direct oral anticoagulants at presentation in patients with major lower gastrointestinal bleeding.Strong recommendation, low quality evidence. 9: ESGE does not recommend withholding aspirin in patients taking low dose aspirin for secondary cardiovascular prevention. If withheld, low dose aspirin should be resumed, preferably within 5 days or even earlier if hemostasis is achieved or there is no further evidence of bleeding.Strong recommendation, moderate quality evidence. 10: ESGE does not recommend routinely discontinuing dual antiplatelet therapy (low dose aspirin and a P2Y12 receptor antagonist) before cardiology consultation. Continuation of the aspirin is recommended, whereas the P2Y12 receptor antagonist can be continued or temporarily interrupted according to the severity of bleeding and the ischemic risk. If interrupted, the P2Y12 receptor antagonist should be restarted within 5 days, if still indicated.Strong recommendation, low quality evidence.

Extravasation Volume at Computed Tomography Angiography Correlates With Bleeding Rate and Prognosis in Patients With Overt Gastrointestinal Bleeding

OBJECTIVE

Despite the identification of active extravasation on computed tomography angiography (CTA) in patients with overt gastrointestinal bleeding (GIB), a large proportion do not have active bleeding or require hemostatic therapy at endoscopy, catheter angiography, or surgery. The objective of our proof-of-concept study was to improve triage of patients with GIB by correlating extravasation volume of first-pass CTA with bleeding rate and clinical outcomes.

MATERIALS AND METHODS

All patients who presented with overt GIB and active extravasation on CTA from January 2014 to July 2019 were reviewed in this retrospective, institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study. Extravasation volume was assessed using 3-dimensional software and correlated with hemostatic therapy (primary endpoint) and with intraprocedural bleeding, blood transfusions, and mortality as secondary endpoints using logistic regression models (P < 0.0125 indicating statistical significance). Odds ratios were used to determine the effect size of a threshold extravasation volume. Quantitative data (extravasation volume, aorta attenuation, extravasation attenuation and time) were input into a mathematical model to calculate bleeding rate.

RESULTS

Fifty consecutive patients including 6 (12%) upper, 18 (36%) small bowel, and 26 (52%) lower GIB met inclusion criteria. Forty-two underwent catheter angiography, endoscopy, or surgery; 16 had intraprocedural active bleeding, and 24 required hemostatic therapy. Higher extravasation volumes correlated with hemostatic therapy (P = 0.007), intraprocedural active bleeding (P = 0.003), and massive transfusion (P = 0.0001), but not mortality (P = 0.936). Using a threshold volume of 0.80 mL or greater, the odds ratio of hemostatic therapy was 8.1 (95% confidence interval, 2.1-26), active bleeding was 11.8 (2.6-45), and massive transfusion was 18 (2.3-65). With mathematical modeling, extravasation volume had a direct and linear relationship with bleeding rate, and the lowest calculated detectable bleeding rate with CTA was less than 0.1 mL/min.

CONCLUSIONS

Larger extravasation volumes correlate with higher bleeding rates and may identify patients who require hemostatic therapy, have intraprocedural bleeding, and require blood transfusions. Current CTAs can detect bleeding rates less than 0.1 mL/min.

Capsule enteroscopy versus scintigraphy for the diagnosis of obscure gastrointestinal bleeding

BACKGROUND

Capsule enteroscopy (CE) and 99mTc Red blood cell (RBC) scintigraphy are frequently used tests in the investigation of obscure gastrointestinal bleeding (OGIB). There is a scarcity of data comparing both diagnostic modalities. This study aims to assess the performance of CE and scintigraphy for the diagnosis of OGIB.

METHODS

Patients who underwent CE and scintigraphy for OGIB were selected and analyzed retrospectively. The hemorrhagic potential of CE findings was rated using Saurin's classification. The concordance between both diagnostic techniques for bleeding detection and localization was analyzed.

RESULTS

Eighty-five patients (62% female), with a median age of 63 years, were included. Capsule enteroscopy identified 37 patients (43%) with high hemorrhagic potential (P2) lesions. Most scintigraphy exams were positive for gastrointestinal bleeding (82%). No concordance was found between the detection of lesions with hemorrhagic potential in CE and scintigraphy (kappa <0). The distribution of P0, P1, and P2 findings was similar in patients with positive or negative scintigraphy (p=0.526). There was no agreement regarding the location of P2 findings in CE and the bleeding detected in the scintigraphy (kappa <0). Patients with P2 lesions had significantly lower median levels of hemoglobin (p=0.002) at presentation. No significant difference was found in hemoglobin values between patients with positive or negative scintigraphy (p=0.058).

CONCLUSION

Significant diagnostic discrepancy was observed between CE and scintigraphy. The findings of CE correlated better with hemoglobin values at presentation than the scintigraphy results. Therefore, scintigraphy didn't appear to be useful in the diagnostic workup of OGIB.  .

Management of life-threatening hemoperitoneum with minimally invasive percutaneous superselective arterial embolization

The management of spontaneous hemoperitoneum centers on clinical suspicion, fluid resuscitation, appropriate early imaging, and therapeutic intervention. Traditionally, explorative laparotomy has been the treatment of choice for idiopathic spontaneous intraabdominal hemorrhage, but as less invasive percutaneous techniques have matured, superselective arterial embolization may play a critical role in emergent treatment. This case report describes a 65-year-old woman with large-volume hemoperitoneum. At angiography, a single pseudoaneurysm of the middle colic artery was identified and treated with superselective endovascular methods.