A Prospective Comparison of Capsule Endoscopy, Helical CT Angiography and Mesenteric Angiography for the Diagnosis of Obscure Gastrointestinal Bleeding (OGIB)

Abstract

The diagnosis of OGIB is often a challenge. Capsule endoscopy (CE) is superior to push enteroscopy and small bowel barium radiography in detecting the source of OGIB. However, its superiority over other conventional imaging modalities remains to be investigated. Aim: To compare the yield of CE, helical CT angiography (CTA) and mesenteric angiography (ANGIO) for the diagnosis of OGIB. Patients and Methods: From June 2004 to October 2005, consecutive patients with OGIB after a prior nondiagnostic upper and lower GI endoscopy were invited to participate in the study. After giving informed consent they underwent CE, helical CTA and ANGIO, performed blindly by separate examiners within the next 7 days. The diagnostic yield for each technique was defined as the frequency of detection of potential or actively bleeding lesions. The diagnostic yield of CE was compared to that of CTA and ANGIO. The accuracy and agreement between CE and the two other procedures [helical CTA + ANGIO] was determined. Results: Twenty-eight patients (16 men and 12 women; mean age, 74+/−2 [SEM] years) with OGIB (overt bleeding in 20 cases and chronic occult blood loss in 8), were prospectively evaluated. CE could be performed in all patients (applicability 100%) whereas the applicability of helical CTA and angiography was 89%, because of contrast allergy in 1 and chronic renal failure in 2 other patients. Overall, a definitive diagnosis was achieved in 19 out of 28 (68%) patients whereas all tests were reported as normal in the other 9. CE identified a bleeding source in a greater proportion of patients 68% (19 of 28) than CTA: 21% (6 of 28, p = 0.006 vs CE), ANGIO: 50% (14 of 28) or CTA+ANGIO: 61% (17 of 28). Likewise, CE was able to diagnose 100% of patients diagnosed by CTA and 86% of patients diagnosed by ANGIO. The most frequent CE findings were: angiodysplasia 12 patients (43%), fresh blood 2, jejunal ulcers 2, jejunal diverticular bleeding 1 and jejunal tumor 1. Capsule CTA + ANGIO CTA ANGIOEndoscopy-----------------------------Sensitivity 88.2% [95% CI: 63.6-98.5] 100% 86% Specificity 62.5% [95% CI: 24.5-91.5] 37% 45% Cohen's Kappa 0.52∗ [95% CI: 0.17-0.89] 0.22 0.32-----------------------------------∗p = 0.007. There were no serious side effects or complications with any procedure. As a result of the CE findings, therapeutic intervention was undertaken in 9 of 19 (47%) patients with positive results. Conclusion: CE is superior to CTA, increases the yield of ANGIO or CTA+ANGIO by 18% and 6% respectively, and have a positive therapeutic impact in almost half of patients with OGIB.