Long-Term Outcomes After Single-Balloon Enteroscopy: Are They Any Different from Double-Balloon Enteroscopy for Vascular Lesions?

Obscure GI bleeding is uncommon, accounting for approximately 5 % of all GI bleeding episodes [1]. With the advent of capsule endoscopy and introduction of balloon enteroscopy to the United States in 2004, endoscopic visualization of the small bowel has become feasible and successful. Double-balloon enteroscopy (DBE) is associated with diagnostic yields of approximately 50–60 %, which exceed 70 % in patients with obscure gastrointestinal bleeding (OGIB) [2]. Performance of video capsule endoscopy (VCE) prior to deep enteroscopy is associated with increased diagnostic yields. In an updated metaanalysis, the yield for DBE was 75 % when a prior VCE study was abnormal, but only 27 % after a negative VCE examination [3]. Single-balloon enteroscopy (SBE) was subsequently introduced into US clinical practice in 2008 in an effort to reduce time and complexity of the double-balloon procedure. Instead of using a second balloon on the distal end of the enteroscope as an anchor when the overtube is advanced, the tip of the enteroscope is deflected during the SBE procedure, creating a ‘‘hook’’ which functions similarly to the second balloon on the DBE enteroscope. Although less data have been published regarding SBE outcomes compared with DBE, initial studies reported somewhat lower diagnostic yields, potentially due to decreased rates of total enteroscopy [4, 5]. Higher total enteroscopy rates and therapeutic interventions with DBE compared to SBE were reported when the enteroscope balloon was removed from the Fujinon system [6]. Nevertheless, a subsequent randomized controlled trial did not confirm these results [7]. In this issue of Digestive Diseases and Sciences, Kushnir et al. [8] from Washington University School of Medicine performed a retrospective cohort study in order to determine long-term outcomes after SBE. While longterm outcomes studies have been performed for DBE and are discussed below [9, 10], this literature contribution is the first long-term outcomes assessment for SBE. Given the conflicting data regarding efficacy of SBE compared to DBE, the major question is whether recurrent bleeding rates differ post-SBE compared to published rates postDBE. In this study, the authors reviewed 147 SBE examinations performed for the evaluation of OGIB between 2008 and 2010, following 110 (75 %) patients for a mean of 24 months post-procedure. Patients who participated in the follow-up phone calls or visits were more likely to have undergone SBE with positive findings in the small bowel leading to endoscopic therapy compared with patients who were lost to follow-up post-enteroscopy (69 vs. 35 %, p \ 0.001). Seventy percent of the patients had undergone VCE studies before the enteroscopy examination. Significant lesions in the small bowel including vascular, ulcerative, and/or suspected neoplasms were detected in 91 % of the patients undergoing capsule endoscopy. A source of bleeding was identified in 95/147 (65 %) SBE examinations including vascular lesions in 54 %, ulcers or erosions in 5 %, and small bowel masses in 3 %. Endoscopic therapy was performed in 76 (52 %) patients, and an additional eight were referred to surgery. Recurrent OGIB occurred in 50/110 (45 %) patients available for follow-up. The authors were unable to find any risk factors associated with recurrent OGIB including Charlson co-morbidity index score, although the number of patients with valvular heart disease (22 %) was small. Recurrent bleeding occurred overall in 31/76 (41 %) of patients with a source found on SBE, and in 19/34 (56 %) of patients with normal L. B. Gerson (&) Stanford University School of Medicine, Stanford, CA, USA e-mail: lgersonmd@yahoo.com