Complications of endoscopy

Effect of short-chain fatty acids on the proliferation and differentiation of the human colonic adenocarcinoma cell line Caco-2

OBJECTIVE

Short-chain fatty acids (SCFA) in the colon may maintain colonocyte differentiation and oppose carcinogenesis. The purpose of this study was to investigate the effects of three SCFA, butyrate, propionate and acetate, on the differentiation, proliferation, and matrix interactions of the Caco-2 human colonic adenocarcinoma cell line.

METHODS

Differentiation was assessed by brush border enzyme expression and the doubling time (proliferation) was calculated directly from serial cell counts and by the logarithmic transformation method. Cell motility (migration) was quantitated by the expansion of a confluent Caco-2 monolayer (after release from a constraining fence) across bacteriologic plastic dishes precoated with saturating concentrations of type I collagen. Results were expressed as mean +/- SE and were analyzed by ANOVA and Bonferroni's modified t-test.

RESULTS

All three SCFA studied altered the Caco-2 phenotype. Treatment with 10 mmol SCFA significantly prolonged the cell doubling time, promoted brush border enzyme expression (cathepsin C), and inhibited the motility of the Caco-2 cells.

CONCLUSIONS

Butyrate, propionate and acetate inhibited the proliferation and motility of a well-differentiated human colonic cancer cell line while promoting the expression of the differentiation marker, cathepsin C. Thus the SCFA produced by bacterial fermentation of dietary fiber may exert a protective effect against the development of colon cancer.

Cost-effectiveness of photodynamic therapy for high-grade dysplasia in Barrett's esophagus

BACKGROUND

Photodynamic therapy appears to be effective in ablating high-grade dysplasia in Barrett's esophagus. Our aim was to identify the most effective and cost-effective strategy for managing high-grade dysplasia in Barrett's esophagus without associated endoscopically visible abnormalities.

METHODS

By using decision analysis, the lifetime costs and benefits of 4 strategies for which long-term data exist were estimated by us: esophagectomy, endoscopic surveillance, photodynamic therapy, followed by esophagectomy for residual high-grade dysplasia; and photodynamic therapy followed by endoscopic surveillance for residual high-grade dysplasia. It was assumed by us that there was a 30% prevalence of cancer in high-grade dysplasia patients and a 77% efficacy of photodynamic therapy for high-grade dysplasia and early cancer.

RESULTS

Esophagectomy cost 24,045 dollars, with life expectancy of 11.82 quality-adjusted life years. In comparison, photodynamic therapy followed by surveillance for residual high-grade dysplasia was the most effective strategy, with a quality-adjusted life expectancy of 12.31 quality-adjusted life years, but it also incurred the greatest lifetime cost (47,310 dollars) for an incremental cost-effectiveness of 47,410 dollars/quality-adjusted life years. The results were sensitive to post-surgical quality of life and survival, and to cancer prevalence if photodynamic therapy efficacy for cancer was less than 50%.

CONCLUSIONS

Photodynamic therapy followed by endoscopic surveillance for residual high-grade dysplasia appears to be cost effective compared with esophagectomy for patients diagnosed with high-grade dysplasia in Barrett's esophagus. Clinical trials directly comparing these strategies are warranted.

Evolving options in the management of esophageal perforation

Esophageal perforation remains a devastating event that is difficult to diagnose and manage. The majority of injuries are iatrogenic and the increasing use of endoscopic procedures can be expected to lead to an even higher incidence of esophageal perforation in coming years. Accurate diagnosis and effective treatment depend on early recognition of clinical features and accurate interpretation of diagnostic imaging. Outcome is determined by the cause and location of the injury, the presence of concomitant esophageal disease, and the interval between perforation and initiation of therapy. The overall mortality associated with esophageal perforation can approach 20%, and delay in treatment of more than 24 hours after perforation can result in a doubling of mortality. Surgical primary repair, with or without reinforcement, is the most successful treatment option in the management of esophageal perforation and reduces mortality by 50% to 70% compared with other interventional therapies.

The management of anticoagulants in the periendoscopic period for patients with atrial fibrillation: a decision analysis

PURPOSE

The management of patients who undergo endoscopy while being treated with warfarin is challenging. We used decision analysis to determine the preferred strategy to manage anticoagulants in the periendoscopic period.

METHODS

We designed a Markov model to estimate costs and quality-adjusted survival during a 10-year period in patients with nonvalvular atrial fibrillation undergoing screening colonoscopy. We compared six alternatives to the continue-warfarin strategy, which was to perform colonoscopy while the patient was taking full-dose warfarin. The hold-warfarin strategy was to stop warfarin 5 days before the colonoscopy. The repeat endoscopy strategy was to continue warfarin for a diagnostic colonoscopy, followed by a repeat procedure after cessation of warfarin if polypectomy was required. The dose-reduction strategy was to reduce the warfarin dose before colonoscopy. The low molecular weight heparin strategy was to administer subcutaneous low molecular weight heparin for 2 days before and 2 days after colonoscopy. The unfractionated heparin strategy was to administer intravenous unfractionated heparin for 2 days before and 2 days after the procedure. The vitamin K strategy was to hold warfarin for 4 days and to administer vitamin K if the international normalized ratio (INR) exceeded 2.0 the day before the procedure, or low molecular weight heparin if the INR was less than 1.5.

RESULTS

For screening colonoscopy, assuming that polyps would be removed in 35% of examinations, the hold-warfarin and dose-reduction arms were both cost-effective strategies. The hold-warfarin arm was most cost-effective if the likelihood of polypectomy exceeded 60%, or if there was a low risk of stroke despite atrial fibrillation. The continue-warfarin strategy was preferred if the probability of polypectomy was 1% or less.

CONCLUSION

Temporary warfarin cessation or halving the warfarin dose for several days before endoscopy was the preferred strategy for most patients. Periendoscopic heparin therapy was not cost-effective for patients with nonvalvular atrial fibrillation.

Laparoscopic repair of iatrogenic endoscopic perforated peptic ulcer

Iatrogenic perforation is an uncommon but inevitable complication of endoscopy. Laparotomy has been the standard treatment for pyloroduodenal perforations caused by endoscopy. Laparoscopic repair is a well-documented treatment modality for spontaneously perforated peptic ulcer. We report our successful laparoscopic suture repair of perforations sustained during upper gastrointestinal endoscopy in two high-risk elderly patients.

Percutaneous radiologic gastrostomy

Gastrostomy is a preferred method of nutrition in patients with impaired ability to eat. Although surgical gastrostomy is a well-established method and has been widely performed in the last century, beginning with early 1980s, percutaneous gastrostomy techniques, either endoscopic or radiologic, has widely gained acceptance. As percutaneous methods have been shown to be an effective, safe, easy to perform and low-cost techniques with low morbidity and mortality rates, nowadays percutaneous gastrostomy is the first method of choice in need of nutrition in patients with functioning gut. In this article authors review the technique of percutaneous radiologic gastrostomy, as well as indications, contraindications, variations of technique, ethical considerations, controversies and comparison with surgical and endoscopic methods.

Closed loop control of sedation for colonoscopy using the Bispectral Index

Sixteen patients undergoing colonoscopy were sedated with propofol using a closed-loop control system guided by the Bispectral Index (BIS). Propofol administration, via a target-controlled infusion, was controlled by a proportional-integral-differential control algorithm. The median (range) propofol target concentration during closed-loop control was 2.3 (1.7-3.6) microg.ml(-1). The performance characteristics of the system were excellent, with a median absolute performance error of 7 (1-15). Patients were drowsy yet rousable, with a median (range) BIS set-point of 80 (75-85). No patient became apnoeic, required airway support or became haemodynamically unstable whilst sedated. Eight patients moaned or moved during colonoscopy and four had recall. Median (range) time to full consciousness was 4 (2-20) min after the end of closed-loop control. Patient and surgeon satisfaction were high. We conclude that BIS may be a suitable control variable for closed-loop control of sedation with propofol.

PEG site infections: a novel use for Actisorb Silver 220

Any breach in the integrity of the skin, such as occurs in wounds and incisions, and intravascular catheters, can act as a portal for the ingress of microorganisms and thereby predispose the patient to infection. The infection, if unchecked, can put the patient at risk of bacteraemia. We have reviewed the care of percutaneous enterostomal gastrostomy (PEG) sites in our trust hospital and in the local community and have implemented practice guidelines to reduce infection risks. These include protocols for skin care around PEG sites, and the use of an antibacterial dressing - Actisorb Silver 220 - to manage local colonization. The preliminary results of this exercise indicate that patient comfort can be improved, hypergranulation reduced, and methicillin-resistant Staphylococcus aureus colonization and infection eradicated.

The role of magnetic resonance cholangiopancreatography in patients with suspected biliary obstruction

Endoscopic retrograde cholangiopancreatography (ERCP) is an accepted and accurate procedure that combines the advantage of diagnosis of biliary obstruction with possible therapeutic endobiliary intervention. However, it is an operator-dependent and invasive procedure that is associated with complications and limitations. Magnetic resonance cholangiopancreatography (MRCP) is a unique noninvasive technique for the diagnosis of biliary obstruction. It is well suited to provide the information required to plan the optimal therapeutic approach for these patients. MRCP has the potential to replace or at least precede ERCP as the first-line imaging effort in the evaluation of suspected biliary obstruction. Significant advantages and some notable limitations inherent to the modality dictate its judicious use in appropriate circumstances. The present article reviews the utility of MRCP in evaluation of biliary obstruction, with brief reference to its principles and techniques.