Middle Gastrointestinal Bleeding

Push Enteroscopy

Push enteroscopy permits evaluation of the proximal small intestine to a distance that is approximately 50 to 100 cm beyond the ligament of Treitz. Dedicated video-enteroscopes (250 cm in length) are commercially available, but if these instruments are not available at the endoscopy site, a pediatric or standard adult colonoscope can be used with distance of insertion 40 to 50 cm beyond the ligament of Treitz. The use of an overtube, back-loaded onto the endoscope insertion tube, may help limit looping of the enteroscope within the stomach and facilitate deeper small bowel intubation. Although the use of an overtube may allow for deeper small bowel intubation, it does not appear to increase the diagnostic yield of the test. The diagnostic yield of push enteroscopy is reported to range from 3% to 70%, with most small bowel findings being vascular lesions (e.g., arteriovenous malformations). Interestingly, most of the lesions diagnosed during push enteroscopy have been found in locations accessible to standard EGD.

With the development of endoscopic tools/devices for dedicated video-enteroscopes, such as biopsy forceps, snares, thermal probes (contact and noncontact), and injection needles, push enteroscopy is preferred over radiologic diagnostic modalities because of the ability to obtain tissue, perform polypectomy or hemostasis if necessary, and mark lesion sites with an India ink tattoo or an endoscopic clip. However, push enteroscopy does not allow for the visualization of the entire small bowel, and adverse events, including perforation and mucosal laceration, have been reported with the use of an overtube. With the advent of small bowel VCE and device-assisted “deep” enteroscopy, diagnostic push enteroscopy is less commonly used today.

Video Capsule Endoscopy

VCE is an endoscopic technology that is readily available worldwide and capable of obtaining endoscopic images from the entire small bowel. VCE is easy, minimally invasive, safe, patient-friendly, and is the first-line diagnostic tool in imaging the small bowel for pathologies. With this realization, there has been rapid uptake and wide acceptance of this endoscopic technology for detecting small bowel abnormalities.

VCE allows complete evaluation of the small bowel (from the duodenum to the ileocecal valve) in 79% to 90% of patients, with a reported diagnostic yield of 38% to 83% in patients with suspected small bowel bleeding ( Figs. 17.1 and 17.2 ; Video 17.1 ). The main utility of VCE lies in its high positive (94%-97%) and negative (83%-100%) predictive values in the evaluation of GI bleeding. Findings at VCE leading to endoscopic or surgical intervention or a change in medical management have been reported in 37% to 87% of patients ( Figs. 17.3 to 17.10 ; Videos 17.2 to 17.10 ). In addition, 50% to 66% of patients have been reported to remain transfusion free without recurrent bleeding at follow-up after VCE-directed interventions. In patients who have had a negative VCE study, rebleeding occurs in 6% to 27%.

The diagnostic yield of VCE may be influenced by multiple factors, with a higher likelihood of positive findings in patients with a hemoglobin less than 10 g/dL, longer duration of bleeding (> 6 months), more than one episode of bleeding, overt as compared with occult bleeding (60% vs. 46%), and performance of VCE within 14 days of a bleeding episode (91% vs. 34%). It has also been shown that detecting a source of bleeding depends on the timing of VCE investigation. In a study by Pennazio et al (2004), evaluating 100 consecutive patients undergoing VCE, the diagnostic yield of VCE was 92% for patients with overt bleeding, 44% for occult bleeders, 67% for patients with prior overt bleeding who were studied within 10 to 14 days of their bleeding episode, and only 33% for those studied by VCE at 3 to 4 weeks after the bleeding episode.

Limitations of VCE include lack of biopsy or therapeutic capabilities, inability to perform endoscopic marking, inability to control movement of the capsule through the GI tract, and difficulty in localizing lesions. Other limitations of VCE include a lack of specificity, with 14% incidental findings in healthy volunteers and a 10% to 36% false-negative rate. Finally, VCE fails to identify the major papilla in a majority of cases and therefore may miss important duodenal lesions because of rapid transit through the duodenal loop. This deficiency may be improved to 60% if a dual camera capsule is used. There are studies to suggest that repeat VCE may be of benefit and increase the diagnostic yield, even when the first VCE study is negative . Diagnostic yield of a repeated VCE was reported to be between 35% and 75% with subsequent management change reported in 39% to 62.5% of the patients, particularly when the type of bleeding changes from occult to overt or there is a hemoglobin drop greater than 4 g/dL. In some patients, luminal debris and bubbles interfere with endoscopic viewing. Some physicians use polyethylene glycol-based preparations, prokinetic agents, simethicone, or a combination of these products before capsule ingestion; however there is no consensus as to the necessity of a pre-VCE bowel preparation.

Some patients may be considered unsuitable candidates for VCE, including patients with cardiac pacemakers, implanted defibrillators, left ventricular assist devices, and patients with suspected small bowel obstruction. Yet, multiple case series suggest that VCE, when performed with careful patient monitoring, is safe in patients with pacemakers and implanted cardiac defibrillators. Patients with swallowing disorders or an unwillingness to voluntarily swallow the capsule may have the capsule endoscopically placed into the duodenum. Historically, overtubes have been used to deliver the capsule into the stomach, whereas standard polypectomy snares and nets have been used for capsule delivery directly into the duodenum. The AdvanCE (US Endoscopy, Mentor, OH) allows endoscopic delivery of the video capsule. The system is a disposable catheter with a sheath diameter of 2.5 mm that is preloaded through the accessory channel of an endoscope. A specialized capsule cup is screwed onto its distal end, and the activated video capsule is loaded into the cup. The upper endoscope and the device are then advanced to the desired anatomical area, and the capsule is released via a deployment apparatus located at the proximal catheter. Additionally, a capsule paired with a magnetic wand (Navi Capsule, IntroMedic, Seoul, Korea) has been created to assist with mobilizing the device through the esophagus, stomach, and into the duodenum to facilitate delivery in patients with delayed gastric emptying.

Capsule retention is a potential adverse event of VCE. The reported incidence of capsule retention ranges from 0% in healthy volunteers, to 1.4% in patients with obscure GI hemorrhage, to 2.1% in patients with suspected small bowel obstruction due to neoplastic lesions, and up to 2.6% in small bowel Crohn's disease, which limits its use in patients with suspected bowel obstruction or strictures until luminal patency is documented. Pre-VCE screening small bowel radiographs have not been able to eliminate capsule retention. To address the problem of capsule retention, the Agile Patency Capsule (PC) was developed (by Given Imaging, now Medtronic, Minneapolis, MN). The PC, being the same size as a video capsule, serves as dummy to assess the patency of the small bowel prior to VCE examination. As one of the major contraindications for VCE is suspicion of small bowel stenosis, routine administration of PCs could enable safe VCE use in a larger patient population by ruling out possible stenosis. The PC system consists of two main parts: the capsule itself, with a radio frequency identification tag (RFID tag), and an external detector system to capture radio frequency signals. The PC is made of lactose and 10% barium, which dissolves when coming into contact with intestinal fluids through the window located at the edge of the capsule, also known as the timer plug. To ensure that the timer plug is not blocked by capsule impaction in a stricture, the second-generation PCs consist of two timer plugs. If PC excretion does not occur, dissolution starts at 30 hours. After 35 hours, 38% of the capsule is dissolved and is 100% dissolved within 72 hours. After dissolution, the remains of the PC encounter no difficulties in passing a small bowel stricture. One drawback of the RFID tag system is the possibility of impaction in a stricture and resultant small bowel ileus or obstruction. Recently however, the use of a “tag-less” Agile PC was reported by Nakamura et al (2014)

The PillCam SB video capsule endoscope (Medtronic) is a wireless capsule (11 mm × 26 mm) composed of a light source, lens, complementary metal oxide semiconductor imager, battery, and wireless transmitter. The PillCam SB has a battery life of approximately 7 to 8 hours, in which time the capsule captures two images per second (approximately 60,000 total images per examination) in a 140-degree field of view and 8 : 1 magnification. The smooth outer coating of the capsule allows easy ingestion and prevents adhesion of intestinal contents as the capsule moves via natural peristalsis from the mouth to the anus. Endoscopic images are transmitted via sensor arrays to a recording device worn as a belt by the patient. The recorded images are downloaded into a Reporting and Processing of Images and Data (RAPID) computer workstation and reviewed as a continuous video by the physician. The PillCam SB VCE offers advanced optics and a wider field of view for imaging the small bowel and also provides Automatic Light Control for optimal illumination of each image. The third generation of PillCam SB (Pillcam SB 3) is now available. CapsoCam by Capsovision (Saratoga, CA) renewed the concept of VCE by offering a capsule with a 360-degree view and on-board image storage, which enables the retrieval of images wire-free after interception of the capsule in the feces. The capsule contains four cameras, which offer high-resolution images and a frame rate up to 20 fps max. Furthermore, two new technologies were developed, Smart Motion Sense Technology and Auto Illumination Technology. Smart Motion Sense Technology enables the capsule to activate its cameras only during capsule motion. When the capsule is stationary, a sensor is used to compare the current frame with the previous frame to control reactivation. Auto Illumination Technology controls the 16 white LEDs to provide the optimal level of illumination. When the capsule is located near the bowel wall, a low light intensity is optimal to capture the best images. A position further away from the wall necessitates a higher light intensity. By adding these software features, battery life is extended up to 15 hours. The first clinical trial that used the CapsoCam reported its safety and efficacy in small bowel evaluation. In a French study by Pioche et al (2014), the concordance between the PillCam SB2 and CapsoCam was evaluated in terms of diagnostic yield and image quality. A kappa value of 0.63 was reported, confirming good concordance between the two capsules. Although the reading time of the CapsoCam was longer, the CapsoCam detected significantly more lesions in a per-lesion analysis. Olympus (Center Valley, PA) has also introduced a next-generation video capsule: ENDOCAPSULE EC-10. With the ENDOCAPSULE EC-10 System, there is improvement in the angle of view, 160 degrees as opposed to 145 degrees in the previous model, battery life has been extended from 8 hours to 12 hours, and there has been an improvement in image quality. Other small bowel capsules with technical features are listed in Table 17.1 .

Device-Assisted Enteroscopy

Deep evaluation of the small bowel can be accomplished with balloon-assisted or non–balloon-assisted enteroscopes coupled with a specialized overtube apparatus. The procedure can be performed via an antegrade approach (via the mouth) or via a retrograde approach (via the anus). In the United States, current options for device-assisted enteroscopes include double-balloon enteroscopy (DBE), single-balloon enteroscopy (SBE), and spiral enteroscopy. A newer, through-the-scope balloon-assisted device that allows “on-demand” enteroscopy is also available.

DBE, initially described and reported by Yamamoto et al (2004), is a novel endoscopic insertion technique that attempts to improve on currently available endoscopic insertion methods to evaluate the entire length of the small bowel. The DBE system (Fujinon Inc, Saitama, Japan), uses a high-resolution, dedicated video enteroscope that has a working length of 200 cm and two soft, latex balloons; one balloon is attached to the tip of the enteroscope, and the other is attached to the distal end of a soft, flexible overt-tube ( Fig. 17.11 ). The balloons can be inflated and deflated using an air pump that is controlled by the endoscopist while monitoring air pressure. The balloons grip the wall of the bowel, allowing the endoscope to be advanced without looping.

The procedure can be performed via an oral or anal approach with or without fluoroscopic guidance. Choice of peroral or transanal approach is usually dictated by suspicion of the location of a possible lesion as determined by preceding small bowel VCE or other small bowel imaging technique. In a peroral approach, when the two balloons reach the duodenum, the overtube balloon is inflated to fix the overtube to the small bowel wall. The overtube is held in place as the endoscope is further inserted. Once the tip of the endoscope is maximally inserted, the balloon on the tip of the endoscope is inflated, the balloon on the overtube is deflated, and the overtube is advanced over the shaft of the endoscope. When the distal end of the overtube reaches the tip of the endoscope, the overtube balloon is reinflated, again fixing the overtube to a second point on the small bowel wall. This sequence is repeated until the entire small bowel is evaluated or further advancement of the endoscope is unable to be performed.

The mean reported procedure times for DBE range from 73 to 123 minutes. The estimated depth of insertion for the peroral antegrade approach is reported to be between 220 and 360 cm and for the transanal retrograde approach between 120 and 180 cm. Reported rates of complete enteroscopy widely vary. Whereas Japanese studies have reported complete enteroscopy rates in the 70% to 86% range, Western series have generally reported much lower completion rates. Reported DBE diagnostic yields have ranged from 40% to 80%, with therapeutic yields of 15% to 55%. In a 2010 study of 200 patients with OGIB bleeding undergoing DBE, the diagnostic yield was 77% for overt bleeding, 67% for patients with occult hemorrhage, and 59% for patients with prior overt bleeding. Moreover, as compared with VCE, DBE has been shown to have similar diagnostic yields in evaluating small bowel disease. Successful performance of endoscopic therapeutic interventions has been reported in 40% to 73% of patients undergoing DBE. Urgent DBE may be better than nonurgent DBE and is associated with a lower recurrent bleeding rate. In addition, one study suggests higher diagnostic yields of DBE for patients with overt bleeding, yet higher recurrence rates in patients presenting with obscure overt bleeding. Moreover, repeat DBE from the same direction may be beneficial, particularly if the patient had a prior positive DBE.

DBE has technical nuances that require specialized training. Furthermore, two operators are needed for the procedure. The procedures are lengthy and potentially uncomfortable for the patient and may be fatiguing for the operators. It is not recommended that both antegrade and retrograde approach procedures be performed on the same day. Antegrade examinations are thought to be easier than retrograde examinations because of difficulty in intubating the terminal ileum via the retrograde approach, with reported failure rates of ileal intubation with retrograde examination ranging from 7% to 30%. Previous abdominal surgery and resultant adhesions can also make the procedure more difficult. The most commonly reported adverse events with DBE include pancreatitis, bleeding, and perforation with an overall rate ranging between 1.2% and 1.6%. Specifically, the rate of pancreatitis is reported to be 0.3% and that of perforation to be between 0.3% and 0.4%. Of note, the perforation risk seems to be higher in patients with surgically altered anatomy, and thus caution is advised in such cases ( Videos 17.11 to 17.16 ).

Single-Balloon Enteroscopy

SBE was introduced in 2007, and uses a dedicated enteroscope with an overtube (SIF-Q180; Olympus America Inc., Center Valley, PA) and a balloon inflation control device that allows automatic balloon pressure control. In contrast to DBE, only the disposable overtube has a nonlatex balloon at its distal end. The enteroscope has a working length of 200 cm, an outer diameter of 9.2 mm, and a 2.8-mm diameter working channel. The overtube (ST-SB1; Olympus) is 140 cm long with a 13.2-mm outer diameter, and its distal end has an inflatable silicone balloon ( Fig. 17.12 ). The balloon is controlled by pressing buttons on the front panel of the Olympus balloon control unit or on a remote control. The internal surface of the overtube is hydrophilic, and lubrication between the outer surface of the enteroscope and the inner surface of the overtube is facilitated by flushing the internal surface of the overtube with water.

The technique for SBE is similar to DBE. The overtube is backloaded onto the enteroscope, and the enteroscope is advanced as far as possible into the small bowel, then anchored by using its flexible tip (as opposed to enteroscope tip balloon-assisted anchoring used in DBE). Subsequently, the overtube is advanced with its balloon deflated to the tip of the enteroscope. The overtube balloon is then inflated while keeping the enteroscope tip flexed. Subsequently, the entire apparatus is withdrawn to allow pleating of the small bowel over the enteroscope and overtube. The efficacy of SBE is generally similar to DBE. Reported diagnostic yields have ranged from 41% to 65% and therapeutic yields from 7% to 50%. The reported range for depth of insertion is 130 to 270 cm for antegrade examinations and 70 to 200 cm for retrograde examinations. Studies suggest that the rate of total enteroscopy with SBE may be lower than that with DBE by up to 24%. SBE is associated with challenges similar to DBE, but overall, SBE is technically less complicated given that only a single balloon must be inflated and deflated by the endoscopist. However, it has been suggested that, due to a lack of an anchoring mechanism on the enteroscope, there can be difficulty in maintaining the enteroscope position in the small bowel as the overtube is advanced. Similar to DBE, transanal retrograde ileal intubation during SBE can be challenging. The procedure times for antegrade and retrograde approaches are similar, and the overall procedure times are comparable to those of DBE. Adverse events reported with SBE are rare and include abdominal pain, fever, mucosal tears, pancreatitis, and perforation.

Spiral Enteroscopy

Spiral enteroscopy was also introduced in 2007, with the potential to provide a simpler and faster deep enteroscopy technique compared with balloon-assisted enteroscopy ( Video 17.17 ). Spiral enteroscopy uses a disposable overtube with a soft, raised spiral ridge that is designed to pleat the small bowel. The overtube is 118 cm long with a soft, raised, spiral helix at its distal end that is either 4.5 mm (low profile) or 5.5 mm (standard profile) in height. The overtube is compatible with enteroscopes that are 200 cm in length and between 9.1 mm and 9.5 mm in diameter ( Fig. 17.13 ). Two different overtubes are available for antegrade (Endo-Ease Discovery SB, Spirus Medical LLC., West Bridgewater, MA) or retrograde (Endo-Ease Vista, Spirus Medical) examinations. The overtube has a coupling device on its proximal end that affixes itself to the enteroscope. This allows for free rotation of the overtube independent of the enteroscope but prevents independent movement of the enteroscope (advancement or withdrawal) relative to the overtube. When the overtube is uncoupled, the enteroscope can then be advanced or withdrawn independent of the overtube. A motorized spiral enteroscopy system has been developed by Olympus and early pilot data in a small group of patients was recently reported in abstract form. Spiral enteroscopy is rather simple to perform, and forward progress through the small bowel can be completed in approximately 18 minutes. Based on the prior literature, the mean procedure times for the anterograde approach have been estimated to be 79 ± 15 min for DBE (10 studies), 65 ± 16 min for SBE (5 studies), and 35 + 6 min for spiral enteroscopy (4 studies). Two operators are required to perform spiral enteroscopy: an endoscopist and an assistant to operate the overtube. Before insertion, the inner lining of the overtube is generously lubricated with the proprietary lubricant supplied with the device. The overtube is then backloaded onto the enteroscope so that approximately 20 cm of the enteroscope protrudes past the distal tip of the overtube. When the overtube and enteroscope are coupled, the overtube should be rotated clockwise for advancement and counterclockwise for withdrawal. For antegrade examination, the overtube and enteroscope are advanced slowly with clockwise rotation of the overtube until the enteroscope tip ideally reaches the ligament of Treitz.

The diagnostic yield of the initial cases of spiral enteroscopy has been reported to be only 33%. More recent prospective data (2011) suggest that the diagnostic yield in patients with a positive VCE study was 57%. Questions have been raised regarding safety concerns with bowel trauma and difficulty in rapid device removal during an emergency. However, there were no major adverse events reported in the early published literature. In a series of 75 patients, 12% reported a sore throat, 27% had superficial mucosal trauma, and 7% had moderate esophageal trauma that did not require intervention. In a retrospective registry study involving 1750 patients, the rate of severe adverse events was reported to be 0.3%, with a small bowel perforation rate of 0.3%.