Histopathological effects of electrosurgical interventions in an in vivo porcine model of colonic endoscopic mucosal resection.

OBJECTIVE: Endoscopic mucosal resection (EMR) in the colon has been widely adopted, but there is limited data on the histopathological effects of the differing electrosurgical currents (ESCs) used. We used an in vivo porcine model to compare the tissue effects of ESCs for snare resection and adjuvant margin ablation techniques. DESIGN: Standardised EMR was performed by a single endoscopist in 12 pigs. Two intersecting 15 mm snare resections were performed. Resections were randomised 1:1 using either a microprocessor-controlled current (MCC) or low-power coagulating current (LPCC). The lateral margins of each defect were treated with either argon plasma coagulation (APC) or snare tip soft coagulation (STSC). Colons were surgically removed at 72 hours. Two specialist pathologists blinded to the intervention assessed the specimens. RESULTS: 88 defects were analysed (median 7 per pig, median defect size 29×17 mm). For snare ESC effects, 156 tissue sections were assessed. LPCC was comparable to MCC for deep involvement of the colon wall. For margin ablation, 172 tissue sections were assessed. APC was comparable to STSC for deep involvement of the colon wall. Islands of preserved mucosa at the coagulated margin were more likely with APC compared with STSC (16% vs 5%, p=0.010). CONCLUSION: For snare resection, MCC and LPCC did not produce significantly different tissue effects. The submucosal injectate may protect the underlying tissue, and technique may more strongly dictate the depth and extent of final injury. For margin ablation, APC was less uniform and complete compared with STSC.

Changes in gene expression of neo-squamous mucosa after endoscopic treatment for dysplastic Barrett's esophagus and intramucosal adenocarcinoma.

BACKGROUND: Endoscopic therapy, including by radiofrequency ablation (RFA) or endoscopic mucosal resection (EMR), is first line treatment for Barrett's esophagus (BE) with high-grade dysplasia (HGD) or intramucosal cancer (IMC) and may be appropriate for some patients with low-grade dysplasia (LGD). OBJECTIVE: The purpose of this study was to investigate the molecular effects of endotherapy. METHODS: mRNA expression of 16 genes significantly associated with different BE stages was measured in paired pre-treatment BE tissues and post-treatment neo-squamous biopsies from 36 patients treated by RFA (19 patients, 3 IMC, 4 HGD, 12 LGD) or EMR (17 patients, 4 IMC, 13 HGD). EMR was performed prior to RFA in eight patients. Normal squamous esophageal tissues were from 20 control individuals. RESULTS: Endoscopic therapy resulted in significant change towards the normal squamous expression profile for all genes. The neo-squamous expression profile was significantly different to the normal control profile for 11 of 16 genes. CONCLUSION: Endotherapy results in marked changes in mRNA expression, with replacement of the disordered BE dysplasia or IMC profile with a more "normal" profile. The neo-squamous mucosa was significantly different to the normal control squamous mucosa for most genes. The significance of this finding is uncertain but it may support continued endoscopic surveillance after successful endotherapy.

Endoscopic resection of subtotal or completely circumferential laterally spreading colonic adenomas: technique, caveats, and outcomes.

BACKGROUND AND STUDY AIMS: Endoscopic mucosal resection (EMR) is an established treatment for large (≥ 20 mm) laterally spreading lesions (LSLs). LSLs with complete or subtotal (> 90 %) circumferential extent (C-LSLs) are generally referred for surgery. Data on technique, efficacy, and safety of EMR for these lesions are absent. The aim of this study was to describe the technique and long-term outcomes of EMR for C-LSLs. PATIENTS AND METHODS: Prospective observational study of consecutive patients referred for EMR of LSL at a tertiary care center over 63 months to April 2015. Amongst 979 patients with LSL, 12 patients with C-LSL were seen. RESULTS: All lesions were tubulovillous adenomas with granular 0 - IIa + Is morphology. Median longitudinal extent was 95 mm (range 60 - 160), 58 % were located in the rectum, and 3 lesions (25 %) had complete circumferential involvement. EMR technical success was 100 %. There were no major adverse events. Symptomatic stricturing occurred in 2 cases (17 %) and was treated with endoscopic balloon dilation (median 4 sessions). Median follow up is 13 months. Minor residual adenoma was found in 7 (58 %) at first surveillance colonoscopy and was treated with snare excision. A total of 10 patients have completed a second surveillance colonoscopy with minor residual adenoma found in only 1 case. No patient required surgery or developed cancer in long-term follow-up. CONCLUSIONS: Endoscopic resection of C-LSL is feasible and safe. Minor residual adenoma is common but endoscopically treatable with long-term cure. Symptomatic stricturing amenable to balloon dilation may occur. Empiric surgical referral for C-LSL based on extensive circumferential involvement may be avoided.ClinicalTrials.gov NCT01368289.

Comparison of the histopathological effects of two electrosurgical currents in an in vivo porcine model of esophageal endoscopic mucosal resection.

BACKGROUND AND STUDY AIMS: Stricture formation is the main limitation of endoscopic resection in the esophagus. The optimal electrosurgical current (ESC) for endoscopic resection in the esophagus and other gastrointestinal sites is unknown. There may be a relationship between the type of ESC used and the development of post-procedure esophageal stricture. Unlike the low power coagulating current (LPCC), the microprocessor-controlled current (MCC), which alternates between short pulse cutting and coagulation, avoids high peak voltages that are thought to result in deep thermal injury. The aim of this study was to determine the histopathological variables associated with these two commonly employed ESCs used for esophageal endoscopic resection. METHODS: Standardized endoscopic resection of normal mucosa by band mucosectomy was performed by a single endoscopist in 12 adult pigs. The procedures were randomized 1 : 1 to either LPCC (ERBE 100 C at 25 W) or MCC (ERBE Endocut Q, Effect 3). Necropsy and esophagectomy were performed at 72 hours after the procedure. Two histopathologists, who were blinded to the ESC allocation, independently assessed the presence and depth of ulceration, necrosis and inflammation. RESULTS: A total of 45 resections were analyzed. In the LPCC and MCC groups, ulceration extending into the muscularis propria was present in 9/24 (37.5 %) and 1/21 (4.8 %) resected specimens, respectively (P = 0.04). Necrosis extending into the muscularis propria was present in 13/24 (54.1 %) and 1/21 (4.8 %) resected specimens, respectively (P = 0.002). One case of microperforation with muscularis propria injury was noted in the LPCC group compared with none in the MCC group. The quantified mean depth of ulceration, necrosis, and acute inflammation was significantly greater in the LPCC group.  CONCLUSIONS: In an in vivo porcine survival model of esophageal endoscopic mucosal resection, the use of MCC resulted in significantly less deep thermal ulceration, necrosis, and acute inflammation compared with LPCC. MCC should be used in preference over LPCC for esophageal endoscopic resection.

Cost Analysis of Endoscopic Mucosal Resection vs Surgery for Large Laterally Spreading Colorectal Lesions.

BACKGROUND & AIMS: Large laterally spreading lesions (LSL) in the colon and rectum can be safely and effectively removed by endoscopic mucosal resection (EMR). However, many patients still undergo surgery. Endoscopic treatment may be more cost effective. We compared the costs of endoscopic versus surgical management of large LSL. METHODS: We performed a prospective, observational, multicenter study of consecutive patients referred to 1 of 7 academic hospitals in Australia for the management of large LSL (≥ 20 mm) from January 2010 to December 2013. We collected data on numbers of patients undergoing EMR, actual endoscopic management costs (index colonoscopy, hospital stay, adverse events, and first surveillance colonoscopy), characteristics of patients and lesions, outcomes, and adverse events, and findings from follow-up examinations 14 days, 4-6 months, and 16-18 months after treatment. We compared data from patients who underwent EMR with those from a model in which all patients underwent surgery without any complications. Event-specific costs, based on Australian refined diagnosis-related group codes, were used to estimate average cost per patient. RESULTS: EMR was performed on 1489 lesions (mean size, 36 mm) in 1353 patients (mean age, 67 years; 52.1% male). Total costs involved in the endoscopic management of large LSL were US $6,316,593 and total inpatient hospitalization length of stay was 1180 days. The total cost predicted for the surgical management group was US $16,601,502, with a total inpatient hospitalization length of stay of 4986 days. Endoscopic management produced a potential total cost saving of US $10,284,909; the mean cost difference per patient was US $7602 (95% confidence interval, $8458-$9220; P < .001). Inpatient hospitalization length of stay was reduced by 2.81 nights per patient (95% confidence interval, 2.69-2.94; P < .001). CONCLUSIONS: In a large multicenter study, endoscopic management of large LSL by EMR was significantly more cost-effective than surgery. Endoscopic management by EMR at an appropriately experienced and resourced tertiary center should be considered the first line of therapy for most patients with this disorder. This approach is likely to deliver substantial overall health expenditure savings. ClinicalTrials.gov, Number: NCT01368289.

The influence of clips on scars after EMR: clip artifact.

BACKGROUND AND AIMS: Laterally spreading lesions ≥20 mm are conventionally removed by EMR. Endoscopic clips are increasingly used to mitigate the risk of delayed bleeding. Clips may alter the endoscopic appearance of the scar after EMR, interfering with the assessment of adenoma recurrence. We aimed to evaluate this. METHODS: Prospective, single-center data from the Australian Colonic Endoscopic resection study (January 2011-May 2015) were analyzed. Patients undergoing EMR of laterally spreading lesions with endoscopic clips used at the EMR defect were eligible. Data included patient and lesion characteristics and procedural, clinical, and histologic outcomes. RESULTS: Clips were used in 111 of 885 lesions (12.5%). A total of 62 of 111 clipped lesions had standardized, high-definition, white light, and narrow-band images of the scars after EMR at first surveillance colonoscopy, and the patients were enrolled. Analysis of the images showed 4 situations: a bland scar (N = 27), residual adenoma (N = 6), mucosal elevation with normal pit pattern (N = 14), or granulation tissue related to the presence of residual clips (N = 15). The latter 2 entities were termed post-EMR scar clip artifact (ESCA). Overall, 29 of 62 previously clipped EMR sites (46.8%) had ESCA at a median follow-up of 5.2 months. Twenty scars had residual clips, and 15 of 20 (75.0%) showed ESCA (P = .002). Lesions clipped for prophylaxis of bleeding were more likely to show ESCA than those clipped for deep mural injury or intraprocedural bleeding (65.5% vs 41.7%; P = .006). ESCA was associated with female sex (P = .010) and greater age (P = .011). CONCLUSIONS: ESCA is characterized by a nodular elevation of the mucosa with a normal pit pattern and can occur with or without residual clips. Prophylactic clip closure and the presence of residual clips are associated with ESCA. ( CLINICAL TRIAL REGISTRATION NUMBER: NCT01368289.).

Endoscopic mucosal resection of laterally spreading lesions involving the ileocecal valve: technique, risk factors for failure, and outcomes.

BACKGROUND AND STUDY AIMS: Endoscopic mucosal resection (EMR) of laterally spreading lesions (LSLs) involving the ileocecal valve (ICV) is technically demanding. Conventionally, these lesions are considered too challenging for endoscopic therapy and are primarily managed surgically. The aims of the study were to describe effectiveness, safety, and outcomes following EMR of LSLs at the ICV. PATIENTS AND METHODS: This was a single-center, prospective, observational, cohort study performed at an academic, tertiary referral center. Patients undergoing EMR for LSLs ≥ 20 mm involving the ICV were recruited over a 5-year period. Standard or cap-assisted colonoscopy with inject-and-resect EMR technique was performed with standardized post-EMR management. Procedural success, safety, and outcomes compared with non-ICV LSLs managed during the same period were analyzed. RESULTS: A total of 53 patients with ICV LSLs were referred for EMR (median age 69 years; median lesion size 35.0 mm; 52.8 % females). Six patients went directly to surgery because of an endoscopic diagnosis of malignancy (n = 2) or technical failure of EMR (n = 4). EMR achieved complete adenoma clearance in 44 out of 47 attempted (93.6 %). Surgery was ultimately avoided in 43/53 (81.1 %). Complications included bleeding in 6.4 %. There were no perforations or strictures. Early adenoma recurrence was detected in 7/40 patients (17.5 %), and 1/22 (4.5 %) had late recurrence. All were successfully managed endoscopically. Factors associated with failure of ICV EMR were ileal infiltration and involvement of both ICV lips. CONCLUSIONS: In the majority of cases, LSL involving the ICV can be effectively treated by EMR on an outpatient basis. In specialized centers, complications are infrequent, and  > 80 % of patients ultimately avoid surgery. Trial registered at ClinicalTrials.gov (NCT01368289).

Prophylactic endoscopic coagulation to prevent bleeding after wide-field endoscopic mucosal resection of large sessile colon polyps.

BACKGROUND & AIMS: Clinically significant postendoscopic mucosal resection bleeding (CSPEB) is the most frequent significant complication of wide-field endoscopic mucosal resection (WF-EMR) of advanced mucosal neoplasia (sessile or laterally spreading colorectal lesions > 20 mm). CSPEB requires resource-intensive management and there is no strategy for preventing it. We investigated whether prophylactic endoscopic coagulation (PEC) reduces the incidence of CSPEB. METHODS: We performed a prospective randomized controlled trial of 347 patients (mean age, 67.1 y; 55.3% with proximal colonic lesions) undergoing WF-EMR for advanced mucosal neoplasia at 3 Australian tertiary referral centers. Patients were assigned randomly (1:1) to groups receiving PEC (n = 172) or no additional therapy (n = 175, controls). PEC was performed with coagulating forceps, applying low-power coagulation to nonbleeding vessels in the resection defect. CSPEB was defined as bleeding requiring admission to the hospital. The primary end point was the proportion of CSPEB. RESULTS: Patients in each group were similar at baseline. CSPEB occurred in 9 patients receiving PEC (5.2%) and 14 controls (8.0%; P = .30). CSPEB was associated significantly with proximal colonic location on multivariate analysis (odds ratio, 3.08; P = .03). Compared with the proximal colon, there was a significantly greater number (3.8 vs 2.1; P = .002) and mean size (0.5-1 vs 0.3-0.5 mm; P = .04) of visible vessels in the distal colon. CONCLUSIONS: PEC does not significantly decrease the incidence of CSPEB after WF-EMR. There were significantly more and larger vessels in the WF-EMR mucosal defect of distal colonic lesions, yet CSPEB was more frequent with proximal colonic lesions. ClinicalTrials.gov NCT01368731.

Early metal stent insertion fails to prevent stricturing after single-stage complete Barrett's excision for high-grade dysplasia and early cancer.

BACKGROUND: Barrett's esophagus with high-grade dysplasia (HGD) or intramucosal adenocarcinoma (IMC) can be effectively treated by single-session EMR, resulting in complete Barrett's excision (CBE). CBE provides accurate histology for staging and clinical confirmation of neoplasia eradication but is limited by a high risk of esophageal stricture formation. OBJECTIVE: To evaluate the effectiveness of prophylactic temporary esophageal stenting to prevent post-CBE stricture formation. DESIGN AND SETTING: Single-center, investigator-initiated feasibility study. PATIENTS: Circumferential, short-segment Barrett's esophagus (≤C3≤M5) with HGD or IMC. INTERVENTION: Single-stage CBE and insertion of a fully covered metal esophageal stent at 10 days that was removed at 8 weeks. Patients were followed for a minimum of 2 surveillance endoscopies. MAIN OUTCOME MEASUREMENT: Symptomatic esophageal stricture formation. RESULTS: At the end of the follow-up period, 8 patients (57.1%) required esophageal dilation for symptomatic CBE-related (n = 7) or stent-related (n = 4) strictures. A median of 3 surveillance endoscopies were performed over a median endoscopic follow-up of 17 months (range 4-25 months). Single-stage CBE successfully eliminated Barrett's intestinal metaplasia and neoplasia in 71.4% and 92.9% of patients, respectively. Four patients were admitted to the hospital, and 4 patients had early stent removal because of pain or dysphagia. LIMITATIONS: Single-center feasibility study. CONCLUSIONS: In a prospective study evaluating prophylactic esophageal stent insertion after single-stage CBE, esophageal strictures formed in more than of half the study cohort, and stents were associated with significant morbidity. An alternative method to reduce stricture formation is required. ( CLINICAL TRIAL REGISTRATION NUMBER: NCT01554280.).

Long-term adenoma recurrence following wide-field endoscopic mucosal resection (WF-EMR) for advanced colonic mucosal neoplasia is infrequent: results and risk factors in 1000 cases from the Australian Colonic EMR (ACE) study.

OBJECTIVE: Wide-field endoscopic mucosal resection (WF-EMR) is an alternative to surgery for treatment of advanced colonic mucosal neoplasia up to 120 mm in size, but has been criticised for its potentially high recurrence rates. We aimed to quantify recurrence at 4 months (early) and 16 months (late) following successful WF-EMR and identify its risk factors and clinical significance. DESIGN: Ongoing multicentre, prospective, intention-to-treat analysis of sessile or laterally spreading colonic lesions ≥20 mm in size referred for WF-EMR to seven academic endoscopy units. Surveillance colonoscopy (SC) was performed 4 months (SC1) and 16 months (SC2) after WF-EMR, with photographic documentation and biopsy of the scar. RESULTS: 1134 consecutive patients were enrolled when 1000 successful EMRs were achieved, of whom 799 have undergone SC1. 670 were normal. Early recurrent/residual adenoma was present in 128 (16.0%, 95% CI 13.6% to 18.7%). One case was unknown. The recurrent/residual adenoma was diminutive in 71.7% of cases. On multivariable analysis, risk factors were lesion size >40 mm, use of argon plasma coagulation and intraprocedural bleeding. Of 670 with normal SC1, 426 have undergone SC2, with late recurrence present in 17 cases (4.0%, 95% CI 2.4% to 6.2%). Overall, recurrent/residual adenoma was successfully treated endoscopically in 135 of 145 cases (93.1%, 95% CI 88.1% to 96.4%). If the initial EMR was deemed successful and did not contain submucosal invasion requiring surgery, 98.1% (95% CI 96.6% to 99.0%) were adenoma-free and had avoided surgery at 16 months following EMR. CONCLUSIONS: Following colonic WF-EMR, early recurrent/residual adenoma occurs in 16%, and is usually unifocal and diminutive. Risk factors were identified. Late recurrence occurs in 4%. Overall, recurrence was managed endoscopically in 93% of cases. Recurrence is not a significant clinical problem following WF-EMR, as with strict colonoscopic surveillance, it can be managed endoscopically with high success rates. TRIAL REGISTRATION NUMBER: NCT01368289.

Actual endoscopic versus predicted surgical mortality for treatment of advanced mucosal neoplasia of the colon.

BACKGROUND: EMR of advanced mucosal neoplasia (AMN) (ie, sessile or laterally spreading lesions of ≥20 mm) of the colon has become an increasingly popular alternative to surgical resection. However, data regarding safety and mortality of EMR in comparison to surgery are limited. OBJECTIVE: To compare actual endoscopic with predicted surgical mortality. DESIGN: Prospective, observational, multicenter cohort study. SETTING: Academic, high-volume, tertiary-care referral center. PATIENTS: Consecutive patients referred for EMR. INTERVENTION EMR MAIN OUTCOME MEASUREMENTS: To predict hypothetical surgical mortality, the Association of Coloproctology of Great Britain and Ireland score, composed of physiological and surgical components, was calculated for each patient. Predicted surgical mortality was then compared with actual outcomes of EMR. The results were validated by an unselected subcohort by using the Colorectal Physiologic and Operative Severity Score for Enumeration of Mortality and Morbidity. RESULTS: Among 1050 patients with AMN treated by EMR, including patients with a predicted mortality rate of greater than 5% (13.8% of cohort), no deaths occurred within 30 days after the procedure. The predicted surgical mortality rate was 3.3% with the Association of Coloproctology of Great Britain and Ireland score (P < .0001). This suggests a significant advantage of EMR over surgery. The results were validated by using the Colorectal Physiologic and Operative Severity Score for Enumeration of Mortality and Morbidity in 390 patients predicting a surgical mortality rate of 3.2% (P = .0003). LIMITATIONS: Nonrandomized study. CONCLUSION: In this large multicenter study of EMR for colonic AMN, the predicted surgical mortality rate was significantly higher than the actual endoscopic mortality rate. Given that endoscopic therapy is less morbid and less expensive than surgery and can be performed as an outpatient treatment, it should be considered as the first line of treatment for most patients with these lesions.

Risk factors for intraprocedural and clinically significant delayed bleeding after wide-field endoscopic mucosal resection of large colonic lesions.

BACKGROUND & AIMS: Wide-field endoscopic mucosal resection (WF-EMR) of large sessile colonic polyps is a safe and cost-effective outpatient treatment. Bleeding is the main complication. Few studies have examined risk factors for bleeding during the procedure (intraprocedural bleeding [IPB]) or after it (clinically significant post-endoscopic bleeding [CSPEB]). We investigated factors associated with IPB and CSPEB in a large prospective study. METHODS: We analyzed data from WF-EMRs of sessile colorectal polyps ≥ 20 mm in size (mean size, 35.5 mm), which were performed on 1172 patients (mean age, 67.8 years) from June 2008-March 2013 at 7 tertiary hospitals as part of the Australian Colonic Endoscopic Resection Study. Data were collected on characteristics of patients and lesions, along with outcomes of procedures and clinical and histologic analyses. Independent predictors of IPB and CSPEB were identified by multiple logistic regression analysis. RESULTS: Of the patients studied, 133 (11.3%) had IPB. Independent predictors included increasing lesion size (odds ratio, 1.24/10 mm; P < .001), Paris endoscopic classification of 0-IIa + Is (odds ratio, 2.12; P = .004), tubulovillous or villous histology (odds ratio, 1.84; P = .007), and study institutions that performed the procedure on fewer than 75 patients (odds ratio, 3.78; P < .001). All IPB was successfully controlled endoscopically. IPB prolonged procedures and was associated with early recurrence (relative risk, 1.68; P = .011). Seventy-three patients (6.2%) had CSPEB. On multivariable analysis, CSPEB was associated with proximal colon location (odds ratio, 3.72; P < .001), use of an electrosurgical current not controlled by a microprocessor (odds ratio, 2.03; P = .038), and IPB (odds ratio, 2.16; P = .016). Lesion size and comorbidities did not predict CSPEB. CONCLUSIONS: In a prospective study of patients undergoing WF-EMR of large sessile colonic polyps, IPB is associated with larger lesions, lesion histology, and Paris endoscopic classification of type 0-IIa + Is. IPB prolongs the duration of the procedure, is a marker for recurrence, and is associated with CSPEB. CSPEB occurs most frequently in the proximal colon and less when current is controlled by a microprocessor.

Snare tip soft coagulation achieves effective and safe endoscopic hemostasis during wide-field endoscopic resection of large colonic lesions (with videos).

BACKGROUND: Wide-field EMR (WF-EMR) of large colonic lesions exposes submucosal vessels, which may result in intraprocedural bleeding (IPB). Ongoing bleeding may obscure the endoscopic field, prolonging the procedure and reducing safety and accuracy. A number of potential interventions to control bleeding exist; however, they have inherent limitations. Safe, readily applicable, inexpensive, and effective therapy to control EMR-IPB has not yet been described. OBJECTIVE: To evaluate the safety and efficacy of the snare tip soft coagulation (STSC) technique to control IPB after WF-EMR of large colonic lesions. DESIGN: Single-center, prospective cohort study. SETTING: Tertiary care referral center. PATIENTS: A total of 196 patients undergoing wide-field colonic EMR for flat and sessile lesions 20 mm or larger. INTERVENTIONS: A standard inject-and-resect EMR technique was applied. IPB was defined as bleeding obscuring the endoscopic field that persisted for 60 seconds or longer. STSC was performed by using the tip of the polypectomy snare to apply soft coagulation (80 W) to sites of IPB. MAIN OUTCOME MEASUREMENTS: Immediate hemostasis, postprocedural bleeding, and other adverse events. RESULTS: A total of 198 lesions (mean size 41.5 mm, 64% in the right colon) were removed in 196 patients (mean age 68 years, 52.5% male). STSC alone achieved effective hemostasis in 40 of 44 cases of IPB (91%). In the remaining 4 cases, additional treatment with coagulating forceps or clips was required to achieve hemostasis. There were no immediate STSC-related adverse events. There was no statistically significant difference between the IPB and non-IPB groups in relation to the use of antiplatelet (P = .2) or anticoagulation agents (P = .4), postprocedural bleeding (P = .8) and adverse event rates (P = .7). LIMITATIONS: Nonrandomized study. CONCLUSIONS: STSC is a simple and efficient first-line technique for achieving hemostasis of IPB during WF-EMR in the colon. It succeeds in the majority of cases and appears to be safe.

Topical submucosal chromoendoscopy defines the level of resection in colonic EMR and may improve procedural safety (with video).

BACKGROUND: Blue dyes such as indigo carmine have become a frequent component of the submucosal injectate for EMR. Confirmation of the correct resection plane and assessment of the resection defect are facilitated by the selective staining of the submucosal layer. Nonstained areas are more difficult to evaluate and may contain inadvertent muscularis propria (MP) injury. The use of topical submucosal chromoendoscopy (TSC) may allow rapid and accurate assessment of these unstained areas and visual recognition of MP injury. OBJECTIVE: To evaluate the utility of a novel technique in the assessment of nonstained areas within the post-EMR defect. DESIGN: Single-center prospective cohort study. SETTING: Academic, tertiary care referral center. PATIENTS: A total of 143 patients undergoing wide-field colonic EMR for sessile lesions 20 mm or larger. INTERVENTIONS: A standard inject-and-resect EMR technique was applied with indigo carmine blue dye in the injectate. Defects with areas of nonstaining were recorded and examined, and then irrigated with the submucosal injectate by using the blunt tip of the injection catheter. MAIN OUTCOME MEASUREMENTS: Detection of additional cases of MP injury by using TSC. RESULTS: A total of 147 EMRs were performed. Focal areas of defect nonstaining were seen in 25 of cases (17%), with no MP injury identified on initial examination. After TSC, 2 additional cases of MP injury were identified, and these were successfully managed endoscopically. Intraprocedural recognition of deep resection increased from 4 cases (2.8%) to 6 cases (4.1%), thereby avoiding potential delayed perforation in 2 patients. LIMITATIONS: Single-center, nonrandomized study. CONCLUSIONS: TSC is simple and effective and rapidly confirms the plane of resection and may improve detection of intraprocedural perforation.

Carbon dioxide insufflation reduces number of postprocedure admissions after endoscopic resection of large colonic lesions: a prospective cohort study.

BACKGROUND: Endoscopic resection (ER) for large colonic lesions is a safe and effective outpatient treatment. Postprocedural pain creates concern for perforation and often results in postprocedure admission (PPA). Carbon dioxide (CO(2)) insufflation has been shown to reduce pain scores after routine colonoscopy, but an influence on more critical outcomes such as PPA has not been shown. OBJECTIVE: To assess the outcomes of patients undergoing ER for large colonic lesions, comparing those having air versus those having CO(2) insufflation. DESIGN: Prospective, observational, cohort study. SETTING: Academic, high-volume, tertiary-care referral center. PATIENTS: Consecutive patients referred for ER of sessile colorectal polyps ≥20 mm. INTERVENTION: ER with air or CO(2). MAIN OUTCOME MEASUREMENTS: Rates of PPA, technical outcomes, complication rates. RESULTS: ER was performed on 575 lesions ≥20 mm, 228 with CO(2) insufflation. Mean lesion size was 36.5 mm. Lesion and patient characteristics were similar in both groups. The use of CO(2) was associated with a 62% decrease in the PPA rate from 8.9% to 3.4% (P = .01). This was mainly because of an 82% decrease in PPA for pain from 5.7% to 1.0% (P = .006). There were no significant difference in the rates of complications. Multiple logistical regression was performed. The adjusted odds ratio (OR) of PPA (OR 0.39; 95% confidence interval [CI], 0.16-0.95; P = .04) and PPA for pain (OR 0.18; 95% CI, 0.04-0.78; P = .02) in the CO(2) group remained significant. LIMITATIONS: Single center, nonrandomized study. CONCLUSION: CO(2) insufflation significantly reduces PPA after ER of large colonic lesions, primarily because of reduced PPA for pain. CO(2) insufflation should be routinely used during ER of large colonic lesions.