The impact of wireless capsule endoscopy on gastrointestinal diseases.

The M2A video capsule endoscope (Pillcam SB, Given Imaging LTD, Yokneam, Israel) is a wireless capsule (11 mm X 27 mm) comprised of a light source, lens, CMOS imager, battery and a wireless transmitter. The capsule moves via peristalsis from the mouth to the anus. The current battery provides 7 to 8 hours of work in which the capsule photographs 2 images per second that are transmitted to a recorder, worn on a belt. The photographs are downloaded into a computer and seen as a continous video film. Since its development, additional support systems have been added: a localization system, a blood detector, a double picture viewer, and, recently, a wider picture angle and better light source, all meant to assist the interpretor.

Pillcam SB was invented to address a need for a better diagnostic tool for small bowel pathologies. In this issue of the Southern Medical Journal, Mazzarolo and Brady give a systemic review of small bowel capsule endoscopy (CE). (1) They review the data on bleeding, Crohn disease and chronic abdominal pain.

The most obvious and first indication to be tested after the capsule invention was obscure gastrointestinal bleeding (OGIB). Many peer reviewed articles compared Pillcam SB to push enteroscopy and other modalities in patients with OGIB. (1-6) The added value of enteroscopy in these patients was in the range of 25 to 30%, while that of the capsule was significantly better (50-67%). Two important take-home messages came out of these studies: 1) the closer the study is performed to the time of actual bleeding, the greater the diagnostic yield; and 2) patients with overt bleeding who required transfusions were those who benefited most. (7,8) Moreover, it was found that a second CE of patients with OGIB and a negative first study increased the diagnostic yield by 20%. (9) We have looked at Pillcam SB in real life by reviewing the charts of the first 160 patients referred for capsule endoscopy by various doctors in 4 centers in Israel and found the capsule to be of value mainly in patients with OGIB (65%). (10) Thus, we and others propose an algorithm in which Pillcam SB will be used early to evaluate the small bowel in a patient with gastrointestinal bleeding with negative gastroscopy and colonoscopy. The outcome of the test will guide the gastroenterologist as to the next invasive step--be it push enteroscopy, ileoscopy, double balloon, or intraoperative enteroscopy.

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The second most studied indication for CE is Crohn disease. CE seems to be superior to all other modalities for diagnosing nonstricturing small bowel Crohn disease, with a number needed to test of 3 to yield one additional diagnosis over small bowel follow-through and 7 for colonoileoscopy. (11) Other subsets of patients that would probably benefit from CE are patients with undetermined colitis, for assessing relapses and postsurgical recurrences, but all these need to be proven in large-scale, controlled studies.

CE has proven to be a valuable tool for the detection of small bowel tumors, follow-up of polyposis syndromes and probably complicated celiac disease. Since its FDA approval 5 years ago for the small bowel, a somewhat different, two-sided camera, 14 frames per second capsule (PillCam ESO) has received FDA approval. It was found to be valuable for the detection of esophageal pathologies, mainly Barrett esophagus and esophageal varices, (12,13) though bigger, multicenter, prospective studies are needed.

Recently, the company has developed a new capsule designed to view the colon (PillCam Colon). The first generation of this capsule has been tested in 3 prospective, blinded, controlled studies with promising results. (14) Thus, if 6 years ago we were astonished to see the performance of the SB capsule, thought to be science fiction, the day is not far in my mind when we will see a total bowel capsule ("PillCam Total Body") that would be given to patients with bleeding, iron deficiency anemia or chronic diarrhea.

The major complication with CE is capsule retention, usually proximal to a stricture. This happens many times despite normal small bowel x-rays. NSAID usage, ischemic bowel event or known Crohn disease carry a higher risk for capsule retention, necessitating surgery in less than 1% of patients. Usually, there are no clinical signs or symptoms, and it is found on a plain abdominal film. This complication was not seen in healthy volunteers.

Thus, CE is a safe, valuable, noninvasive, innovative tool for the diagnosis of small bowel pathologies. Is it perfect? No, but we are in the learning curve, and it is improving yearly. Newer versions of pills and software will allow better images and localization. Advanced versions will hopefully also allow total bowel view, therapeutic modalities and rapid reading. Are we there yet?--No, but almost.

References

1. Mazzarolo S, Brady P. Small bowel capsule endoscopy: a systemic review. South Med J 2007;100:274-280.

2. Lewis BS, Swain P. Capsule endoscopy in the evaluation of patients with suspected small intestinal bleeding: Results of a pilot study. Gastrointest Endosc 2002;56:349-354.

3. Scapa E, Jacob H, Lewkowicz S, et al. Initial experience of wireless-capsule endoscopy for evaluating occult gastrointestinal bleeding and suspected small bowel pathology. Am J Gastroenterol 2002;97:2776-2779.

4. Ell C, Remke S, May A, et al. The first prospective controlled trial comparing wireless capsule endoscopy with push enteroscopy in chronic gastrointestinal bleeding. Endoscopy 2002;34:685-689.

5. Saurin JC, Delvaux M, Gaudin JL, et al. Diagnostic value of endoscopic capsule in patients with obscure digestive bleeding: blinded comparison with video push-enteroscopy. Endoscopy 2003;35:576-584.

6. Mylonaki M, Fritscher-Ravens A, Swain P. Wireless capsule endoscopy: a comparison with push enteroscopy in patients with gastroscopy and colonoscopy negative gastrointestinal bleeding. Gut 2003;502:1122-6.

7. Pennazio M, Santucci R, Rondonotti E, et al. Outcome of patients with obscure gastrointestinal bleeding after capsule endoscopy: report of 100 consecutive cases. Gastroenterology 2004;126:643-653.

8. Estevez E, Gonzalez-Conde B, Vazquez-Iglesias JL, et al. Diagnostic yield and clinical outcomes after capsule endoscopy in 100 consecutive patients with obscure gastrointestinal bleeding. Eur J Gastroenterol Hepatol 2006;18:881-888.

9. Bar-Meir S, Eliakim R, Nadler M, et al. Second capsule endoscopy for patients with severe iron deficiency anemia. Gastrointest Endosc 2004;60:711-713.

10. Fireman Z, Eliakim R, Adler S, et al. Capsule endoscopy in real life: a four-centre experience of 160 consecutive patients in Israel. Eur J Gastroenterol Hepatol 2004;16:927-931.

11. Triester SL, Leighton JA, Leontiadis GI, et al. A meta-analysis of the yield of capsule endoscopy compared to other diagnostic modalities in patients with non-stricturing small bowel Crohn's disease. Am J Gastroenterol 2006;101:954-964.

12. Eliakim R, Sharma VK, Yassin K, et al. A prospective study of the diagnostic accuracy of PillCam ESO esophageal capsule endoscopy versus conventional upper endoscopy in patients with chronic gastroesophageal reflux diseases. J Clin Gastroenterol 2005;39:572-578.

13. Eisen G, Eliakim R, Zaman A, et al. The accuracy of PillCam ESO capsule endoscopy versus conventional upper endoscopy for the diagnosis of esophageal varices: a prospective three-center pilot study. Endoscopy 2006;38:31-35.

14. Eliakim R, Fireman Z, Adler SN. For the Colon Capsule Study Group. PillCam Colon in comparison with standard colonoscopy in the detection of polyps-results from the first prospective multi-center study. Am J Gastroenterol 2006;38:963-970.

The trouble with being in the rat race is that even if you win, you're
still a rat.
--Lily Tomlin

Rami Eliakim, MD

From the Department of Gastroenterology, Rambam Health Care Campus, Rappaport School of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.

Reprint requests to R. Eliakim, MD, Department of Gastroenterology, Rambam Health Care Campus, Bat Galim, Haifa, P.O.B. 9602, Israel 31096. Email: [e-mail]

Accepted August 24, 2006.