Complications in gastrointestinal endoscopy

Identification of potential complications during endoscopy and knowledge of therapeutic possibilities is of pivotal importance for optimal management of patients. Every 2 years, Peter Meier conducts a renowned endoscopy symposium with an international expert faculty from all over the world to highlight the latest concepts of complication management in gastrointestinal endoscopy.1 The 4th International Symposium on Complications in GI Endoscopy took place in the beautiful city of Hannover in Germany and was conducted to identify critical incidents and complications, to learn how to communicate unforeseen events, to develop strategies to avoid or even to minimize complications and also to demonstrate therapeutic measures for the eventuality of a complication. This editorial will highlight some of the key aspects of the symposium thereby trying to give readers a comprehensive overview of the symposium. The next International Symposium on Complications in GI Endoscopy will be held in November 2017 in the Hanseatic City of Hamburg in Germany. With James Lau from Hong Kong as one of the scientific committee chairs, the next symposium will specifically address colleagues from Asia to join the conference and to discuss management of complications regarding technical, procedural, ethical, psychological and legal aspects. Therefore, in particular, we would like to invite our colleagues from Asia to join us in the renowned city of Hamburg in Germany next year. Most endoscopic procedures in Europe and the USA are carried out under sedation, and cardiopulmonary adverse events occur in up to 11% of procedures thereby accounting for most (>60%) endoscopy-related adverse events.2 Risk factors include pre-existing cardiopulmonary diseases, age, and ASA class 3 or higher. Therefore, proper selection of patients is of paramount importance to reduce morbidity and mortality. Moreover, adequate training is required, especially when sedation is done by non-anesthesiologists. However, recent studies have highlighted that nurse-assisted propofol sedation or physician-supervised nurse administration of propofol is safe and effective for routine endoscopic procedures.3 Infectious adverse events are mostly associated with invasive procedures. High rates of bacteremia have been reported after esophageal dilation, sclerotherapy of varices and procedures of obstructed bile ducts. It seems important to highlight the high risk of infection even after percutaneous endoscopic gastrostomy (PEG) placement, which is up to 26%. One recent meta-analysis of 12 randomized trials has shown a statistically significant reduction in the incidence of peristomal infection with prophylactic antibiotics.4 Therefore, peri-interventional antibiotic prophylaxis (e.g. single dose of cephalosporin or penicillin-based prophylaxis) is strongly recommended. Moreover, new therapeutic techniques such as endoscopic full-thickness resection and endoscopic gastroenterostomy require at least a peri-interventional antibiotic prophylaxis. Exact recommendations on how to prevent infections after endoscopic procedures have recently been introduced by the American Society for Gastrointestinal Endoscopy (ASGE) Standards of Practice committee and should be followed by endoscopists in order to reduce the rate of preventable adverse events.5 Pancreatitis is a special, potential serious complication of endoscopic retrograde cholangiopancreatography (ERCP). Post-ERCP pancreatitis occurs in approximately 3.5% of patients with a wide range of up to 16%.5 Risk factors include older age, female gender, history of pancreatitis, pancreatic sphincterotomy, precut sphincterotomy, endoscopic papillary balloon dilation and experience of the endoscopist. Therefore, adequate patient selection and alternative approaches (e.g. endoscopic ultrasonography [EUS], magnetic resonance cholangiopancreatography [MRCP]) should be considered before carrying out the procedure. Of note, meta-analyses have shown that giving rectal indomethacin or diclofenac before the ERCP can significantly reduce the incidence of post-ERCP pancreatitis.6 The same effect was shown for nitroglycerin. However, as a result of the side-effect profile, the drug is not commonly recommended for prevention of pancreatitis after ERCP. Besides, temporary pancreatic duct stenting in high-risk populations and wire-guided cannulation before contrast injection have been shown to lower the risk of post-ERCP pancreatitis.6 Bleeding is common after endoscopic interventions in the gastrointestinal tract. However the authors agree that bleeding that can be managed endoscopically without changing patient management (e.g. no blood transfusion, no prolonged hospitalization) should not be considered a real complication. Most bleeding can be managed endoscopically by using standard endoscopic equipment including injection, coagulation, hemoclips or spraying agents and is more likely in patients with coagulopathies and thrombocytopenia. Accordingly, therapeutic endoscopic procedures should be done only when the platelet level is 50 000/mL, although some smaller studies suggest that a platelet count of 20 000/mL may also be sufficient.7 Other risk factors for bleeding that have been identified include hypertension, polyps >17 mm in diameter, stalks >5 mm in diameter, and sessile or malignant lesions. The recent ASGE guidelines for management of antithrombotic agents stated that the risk of bleeding while receiving antithrombotic therapy should always be weighed against the risk of thrombotic events when the antithrombotic therapy is withheld.8 Although bleeding can mostly be managed endoscopically, thrombotic events may have a devastating course for patients and continuation of antithrombotic therapy might be preferable. Multiple studies did not find aspirin use associated with post-polypectomy bleeding.2 One of the most feared complications in endoscopy is perforation. Perforation during diagnostic procedures is extremely rare and mostly associated with predisposing factors including the presence of diverticula, malignancies, strictures or severe inflammation. Mortality rate of perforation is dependent on the type and location. Mortality rates of 5% have been described for colon perforations but mortality can rise to 36% for perforations in the esophagus.2, 7 Perforation occurring during diagnostic procedures is often difficult to identify and recent data have indicated that diagnostic perforations are significantly more often associated with the need for surgery.9 In contrast, perforation occurring during endoscopic therapeutic procedures is mostly well circumscribed and often clearly visible. As the environment has also been prepared for the therapeutic procedure (e.g. adequate bowel preparation before polypectomy), the risk of infection is normally reduced. Two types of perforation include: (i) immediate-type perforation (deep resection, traumatic); and (ii) delayed-type perforation (coagulation necrosis, partial muscularis propria injury). Immediate perforation can mostly be treated by the use of hemoclips, over-the-scope-clip, the clip-and-loop technique or endoscopic suturing. Delayed perforation is mostly restricted to conservative management with i.v. hydration, food restriction, antibiotics and surgery. Accordingly, early recognition and identification of a perforation is of tremendous importance in order to decrease morbidity and mortality. In this context, the Michael Bourke group recently described the so called ‘target sign’ after endoscopic resection.10 By using interventional chromoendoscopy (adding blue dye to the injection solution), the defect should have a homogeneous blue appearance after resection. Poorly stained areas are suspicious for deep injury and should be treated endoscopically. Two types of target sign are visible, one at the resection side and one at the resected specimen. Therefore, evaluations of both sides are helpful to exclude deep injury and may expedite the decision if a potential complication needs to be treated. Endoscopic treatment of perforations is most effective in a clear environment. However, when there is visible flow of stool or fluids into the perforation side, the risk of peritonitis is very high and early surgery should be considered even when the hole could be closed. Taking the above-mentioned complications into account, the endoscopist should also be aware that a missed or inaccurate diagnosis should be considered a complication of gastrointestinal endoscopy. Recent data evaluating the benefit of new endoscopes for adenoma detection have shown that a significant number of lesions can be missed during routine endoscopic examinations. It is therefore important to develop new strategies to improve the quality of endoscopic examinations. Taken together, complications in gastrointestinal endoscopy are inevitable. Moreover, as endoscopic practice is becoming more therapeutic and now also involves the extraluminal side (e.g. for gastroenterostomy and natural orifice transluminal endoscopic surgery [NOTES]), the potential for adverse events will increase. Therefore, knowledge of potential adverse events, their frequency and risk factors, as well as knowledge on how to diagnose and treat the complication is of paramount importance for proper selection of patients, the preoperative discussion and effective therapy of our patients. Authors declare no conflicts of interest for this article.