Indications and Limitations Associated with the Patency Capsule Prior to Capsule Endoscopy

A systematic review of capsule aspiration in capsule endoscopy

Background

Capsule endoscopy (CE) is safe and widely accepted for small bowel (SB) investigation and an alternative to colonoscopy in specific clinical circumstances. As the capsule is orally ingested, the potential risk of aspiration is undoubtedly a constant concern among clinicians. However, it is a rare occurrence and often reported as isolated cases. Therefore, this review systematically compiles all the available data on capsule aspiration in the literature with an aim to provide an update on this complication of CE.

Methods

A systematic literature search was performed on PubMed with the search terms 'capsule endoscopy' AND 'aspiration', searched as keywords and MeSH. All observational cohort studies that reported aspiration among complications/outcomes, case reports and series on capsule aspiration were included. Manual citation search was performed. Two extractors reviewed abstract and full-text and performed data extraction.

Results

We found 95 relevant articles, and cross-checking references led to the inclusion of an additional 19 articles. We removed 57 and ended with 57 references-with 63 cases of aspirated capsules. One death was reported. The median age was 78, and there was male preponderance. The most common indication for CE was anaemia, and only aspiration of small bowel CE (SBCE) was reported. 61.9% of the aspirations were symptomatic; the most common symptom was coughing. 69.8% of capsules ended in the bronchus, but only 4 cases experienced desaturation. Thirty-two patients needed intervention for retrieval; the aspiration was self-resolved in the remaining. Only four patients had a history of dysphagia. Thirteen instances of aspiration were detected due to real-time viewing, and 24 cases from reviewing the capsule data afterwards.

Conclusions

With only 63 cases of aspirated capsules reported in the literature, this event remains rare, is safely managed, and should not discourage patients from the procedure. The importance of careful patient selection is crucial to minimize the likelihood of aspiration and capsule administration should be approached with precautions.

The Future of Minimally Invasive Capsule Panendoscopy: Robotic Precision, Wireless Imaging and AI-Driven Insights

In the early 2000s, the introduction of single-camera wireless capsule endoscopy (CE) redefined small bowel study. Progress continued with the development of double-camera devices, first for the colon and rectum, and then, for panenteric assessment. Advancements continued with magnetic capsule endoscopy (MCE), particularly when assisted by a robotic arm, designed to enhance gastric evaluation. Indeed, as CE provides full visualization of the entire gastrointestinal (GI) tract, a minimally invasive capsule panendoscopy (CPE) could be a feasible alternative, despite its time-consuming nature and learning curve, assuming appropriate bowel cleansing has been carried out. Recent progress in artificial intelligence (AI), particularly in the development of convolutional neural networks (CNN) for CE auxiliary reading (detecting and diagnosing), may provide the missing link in fulfilling the goal of establishing the use of panendoscopy, although prospective studies are still needed to validate these models in actual clinical scenarios. Recent CE advancements will be discussed, focusing on the current evidence on CNN developments, and their real-life implementation potential and associated ethical challenges.

Retention of small bowel capsule endoscopy

PURPOSE OF REVIEW

Capsule endoscopy is widely recognized as a safe and effective procedure to evaluate the small bowel and/or the colon noninvasively. Although infrequent, capsule retention is the most feared adverse event related to this technique. A better knowledge of risk factors, improvement of patients' selection and precapsule patency assessment may further contribute to reducing the incidence of capsule retention, even in patients at increased risk for this complication.

RECENT FINDINGS

This review addresses the main risk factors for capsule retention, strategies for risk reduction such as patients' selection, dedicated cross-sectional imaging and rational use of the patency capsule, as well as management options and outcomes in the case of capsule retention.

SUMMARY

Capsule retention is infrequent, and it is usually manageable conservatively with favorable clinical outcomes. Patency capsules and dedicated small-bowel cross-sectional techniques such as CT or MR enterography should be used selectively and are both effective in decreasing the rate of capsule retention. However, none of them can completely eliminate the risk of retention.

Modified method of patency judgement using patency capsule prior to capsule endoscopy in clinical practice

In 2012, Japan approved the use of a tag-less patency capsule (PC), which evaluates gastrointestinal patency before small-bowel capsule endoscopy (SBCE). This study aimed to evaluate the validity of our modification on the passage criteria for this PC in clinical practice. We retrospectively enrolled 326 consecutive patients who underwent PC examination before SBCE. If X-ray could not reveal the PC in the body during the judgement time (30–33 h after ingestion), we defined it as ‘estimated patency’ and performed SBCE. We employed plain computed tomography (CT) for the second judgement, as needed. The overall patency rate was 95.1%. By X-ray, 41 (12.6%) patients were judged to have ‘estimated patency’, and SBCE could be safely performed. Plain CT judgement was necessary in 106 patients (32.5%). One PC case had a residual coating film associated with stenosis in a patient with Crohn’s disease (CD), and one (0.3%) SBCE case had capsule retention resulting from false CT judgement. Multivariate analysis revealed that established CD and inpatient were factors related to no-patency. In conclusion, PC is useful for examining gastrointestinal patency, keeping in mind CT misjudgement. If PC was not found in the body via X-ray, performing SBCE as ‘estimated patency’ seemed appropriate.