Capsule endoscopy improved diagnostic yield in patients with obscure gastrointestinal bleeding, but that did not translate into better outcomes in a randomized study comparing the procedure with dedicated small bowel contrast radiography, Dr. Loren A. Laine and his colleagues said in an article appearing in the May issue of Gastroenterology.
Diagnostic yield was significantly greater in 66 patients randomized to undergo capsule endoscopy than in 70 who underwent dedicated small bowel contrast radiography (30% vs. 7%), but the primary end point of further bleeding occurred in 30% of the capsule endoscopy patients, compared with 24% of the contrast radiography patients, the investigators reported (Gastroenterology 2010 May [doi: 10.1053/j.gastro.2010.01.047]).
Patients in the study had an average age of about 55 years; 54 had overt bleeding and 82 had occult bleeding at randomization. Patients who had overt bleeding at randomization were almost twice as likely as those with occult bleeding to have further bleeding during the study; 39% vs. 20% had further bleeding in the overt and occult bleeding groups, respectively.
Also, those with overt bleeding at randomization who were assigned to the capsule endoscopy group were more likely to have further bleeding, compared with those with overt bleeding assigned to the radiography group (50% vs. 29% had further bleeding, respectively).
Those with occult bleeding at randomization had similar rates of further bleeding regardless of randomization; 18% and 21% had further bleeding in the capsule endoscopy and radiography groups, respectively, the investigators noted.
No significant differences were seen between the capsule endoscopy and radiography groups in regard to the need for transfusions, subsequent hospitalization, or additional interventions for diagnosis or treatment of bleeding, said Dr. Laine of the University of Southern California, Los Angeles, and his colleagues.
The findings demonstrate that most patients with obscure GI bleeding do well regardless of whether abnormalities are detected by capsule endoscopy, and that further interventions might be necessary regardless of the success or failure of the procedure.
“In addition, merely visualizing a lesion on capsule (or radiography) does not document that the lesion is the cause of bleeding unless active bleeding or stigmata of recent hemorrhage are also identified,” they wrote.
The findings of this study have no bearing on current recommendations from the American Gastroenterological Association regarding the management of patients with obscure GI bleeding, because the study did not directly assess the AGA management algorithm, which calls for capsule endoscopy after a negative upper endoscopy and colonoscopy in those with obscure GI bleeding, subsequent interventions directed by the findings of a positive capsule endoscopy, and observation or – if warranted – further diagnostic testing in those with no bleeding source identified.
In this study, capsule endoscopy was evaluated only after patients had a negative upper endoscopy, colonoscopy, and push enteroscopy; the investigators used this approach because push enteroscopy has the ability to obtain diagnostic specimens and provide therapy, and because it is likely to identify nearly half of the abnormalities seen on capsule endoscopy, the explained.
“Future randomized trials will need to assess whether push enteroscopy or capsule should be the first test after negative upper endoscopy and colonoscopy and whether capsule endoscopy would improve outcomes if performed prior to push enteroscopy,” they said.
The findings do not rule out the possibility that some patients may benefit from capsule endoscopy, they noted, adding that future studies also should attempt to identify clinical characteristics that help stratify the use of capsule endoscopy and other interventions. However, the development of technology allowing external control in capsule endoscopy, and equipping it to perform diagnostic and therapeutic interventions, might be necessary before significant improvements in clinical outcomes associated with its use in this population become apparent, they concluded.
This study received grant support from the American Society for Gastrointestinal Endoscopy Wireless Video Capsule Endoscopy Clinical Research Award. The authors reported that they have no disclosures relevant the study.
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Loren A. Laine博士及其同事在一项随机研究中对胶囊内镜检查与小肠专用对比造影检查进行了比较，他们发现，胶囊内镜检查可提高不明原因消化道出血的诊断率，但这并不意味其可改善患者的转归。该研究发表于5月份出版的《胃肠病学》(Gastroenterology)杂志。
研究者表示，随机接受胶囊内镜检查的66例患者的诊断率显著高于接受小肠专用对比造影检查的77例患者(30%对7%)，但胶囊内镜组有30%的患者达到主要终点，即出现进一步出血，而对比造影组的这一比例为24%(Gastroenterology 2010 May [doi: 10.1053/j.gastro.2010.01.047])。
患者的平均年龄约为55岁；随机分组时，54例存在显性出血，82例存在不明原因出血。随机分组时显性出血的患者在研究期间出现进一步出血的比例是不明原因出血患者的近2倍(39%对20%)。
此外，胶囊内镜组显性出血患者的进一步出血发生率高于造影组显性出血患者(50%对29%)。
研究者指出，胶囊内镜组与造影组不明原因出血患者的进一步出血发生率相似，分别为18%和21%。
南加州大学洛杉矶分校的Laine博士及其同事表示，在是否需要输血、住院或需要采用额外的出血诊断或治疗干预措施方面，胶囊内镜组与造影组之间无显著差异。
该结果表明，不管病变是否被胶囊内镜检出，大部分不明原因消化道出血患者的状况均良好，并且不管胶囊内镜检查是否实施成功，均有必要采取进一步干预措施。
他们写道：“此外，仅在胶囊内镜或造影X线片上观察到病变并不意味该病变就是出血的原因，除非还同时检出活动性出血或近期出血征象。”
该研究结果与美国胃肠病学会(AGA)针对不明原因消化道出血患者的当前治疗建议无关，因为该研究并未直接借鉴AGA治疗法则。AGA治疗法则要求，如果不明原因消化道出血患者的上消化道内镜和结肠镜检查结果为阴性，则应对其进行胶囊内镜检查，如胶囊内镜检查结果为阳性，则应在随后采取干预措施并进行观察，或在必要情况下，对出血原因不明的患者进行进一步诊断检查。
他们解释说，在该研究中，仅在患者的上消化道内镜、结肠镜和推进式小肠镜检查结果为阴性时，才对其进行胶囊内镜检查；研究者采用此法一是因为推进式小肠镜能够获得诊断样本并提供治疗，二是因为其能够检出胶囊内镜所观察到的近半数病变。
他们说：“需要进行进一步随机试验，以确定在上消化道内镜和结肠镜检查结果为阴性后，是应该先进行推进式小肠镜检查还是胶囊内镜检查，并在胶囊内镜检查先于推进式小肠镜检查进行的情况下，评价胶囊内镜检查是否有助于改善转归。”
他们指出，该结果未排除一些患者从胶囊内镜检查中获益的可能性，并且未来研究还应设法明确有助于指导胶囊内镜和其他干预措施的应用的临床特征。他们总结说，但在得以实现显著改善该患者人群的胶囊内镜检查相关临床转归之前，有必要开发允许外部控制胶囊内镜的技术，并将该技术用于进行诊断和治疗干预。
该研究获得美国胃肠内镜协会无线视频胶囊内镜临床研究奖的资金支持。作者声明，他们没有与该研究相关的经济利益关系。
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