Validation of the Modified Location-based Resect-and-discard Strategy Requiring Pathology Examination of Sigmoid Diminutive Polyps.

BACKGROUND AND AIMS: Recently, the location-based resect-and-discard (LBRD) strategy, which does not depend on optical diagnosis, was developed and demonstrated different surveillance interval agreement with the pathology-based reference in several researches. We aimed to evaluate the performance of LBRD in our first-time colonoscopy cohort, and improve the LBRD. METHODS: The first-time colonoscopy with complete pathologic information were enrolled. The accuracy of LBRD strategy applied in diminutive polyps in different colonic segments was used as indicator to develop modified LBRD (mLBRD) strategy. Surveillance interval agreement with pathology-based reference was compared between LBRD and mLBRD. The ≥ 90% agreement with pathology was used as benchmark. RESULTS: The polyps in sigmoid colon were significantly associated with higher proportion of neoplastic compared with polyps in rectum. The accuracy of LBRD applied in polyps in sigmoid colon were only 53.5%, which was significantly lower than that applied in polyps in other colonic segments. Thus, we hypothesized that mLBRD requiring pathology examination of diminutive polyps in sigmoid colon was more efficient in clinical use. The mLBRD significantly outperformed LBRD in surveillance interval agreement with pathology-based reference (90.2% vs. 83.4%, P<0.001), had lower proportion of patients assigned a longer surveillance interval (3.6% vs. 10.5%, P<0.001) and reached the benchmark, although the proportion of patients with an immediate surveillance interval recommendations and pathology examination avoided decreased. CONCLUSIONS: The mLBRD, but not LBRD, achieved sufficient surveillance interval agreement with pathology-based surveillance interval assignment and reduced over 30% of pathology examinations.

Negative Effects of Endoscopists' Fatigue on Colonoscopy Quality on 34,022 Screening Colonoscopies.

BACKGROUND AND AIMS: There is still considerable controversy surrounding the relationship between fatigue of endoscopists and the quality of colonoscopy. The aim of this study is to comprehensively explore the association between fatigue and adenoma detection rate (ADR) and cecal intubation rate (CIR). METHODS: The mixed effects logistic regression model was used to explore the relationship between fatigue- related factors including procedure order, session of procedures and the day of week and ADR as well as CIR. RESULTS: When controlling for confounders, the day of week (Monday as reference, Friday, p=0.022; weekends, p=0.015) and session of procedures (P<0.001) were significantly associated with ADR while procedure order (<5 as reference, 6-10, p<0.001; >10, p=0.001) and session of procedures (p=0.004) were independent predictors for CIR. Additionally, there was a significant downward trend on ADR and CIR with the approaching of weekends (p=0.005) and increasing procedure orders (p<0.001), respectively. In the subgroup analysis stratified by gender, age and workload intensity, significant lower ADR was found in the afternoon in all subgroups (male, p<0.001; female, p=0.005; <40 years, p<0.001; ≥40 years, p=0.020; intensity<50 per month, p=0.017; intensity≥50 per month, p<0.001) but the downward trend on ADR as the week progressed was only found in endoscopists with male gender (p=0.011), age<40 (p=0.027) and high workload intensity (p=0.003). Moreover, a significant downward trend on CIR as the procedure order increased was found in all subgroups except endoscopists with age≥40 (male, p=0.005; female, p<0.001; <40 years, p<0.001; intensity<50 per month, p=0.001; intensity≥50 per month, p<0.001). CONCLUSIONS: Colonoscopies in the afternoon will affect ADR negatively while increasing procedure order will cause a lower CIR. Importantly, the significant negative influence of Friday and weekends on ADR was first discovered in this study. Moreover, endoscopists with female gender and advanced age (≥40) but not high workload intensity showed superiority in resistance of fatigue caused by the end of the week and increasing daily procedures.

Comprehensive evaluation of the learning curve to achieve satisfactory adenoma detection rate.

BACKGROUND AND AIM: The number of colonoscopies required to reach satisfactory adenoma detection rate (ADR) is not well established. The aim of this study was to identify the appropriate number of procedures required to attain satisfactory ADR for those well-trained endoscopists who have a cecal intubation rate (CIR) ≥ 90% and start to perform colonoscopy independently. METHODS: All endoscopists with compelete independent colonoscopy data during career in our database were enrolled. The number of procedures required to achieve ADR ≥ 20% was identified by cumulative summation (Cusum), learning curve Cusum (LC-Cusum), and moving average method. Mixed effect logistic regression model was developed to determine the relationship between endoscopist as well as patient-related factors and adenoma detection. RESULTS: A total of 24 943 procedures and 14 endoscopists were enrolled. By Cusum analysis, the interest point was at 207 procedures. By LC-Cusum analysis, 71% (10/14) and 86% (12/14) of endoscopists had attained satisfactory ADR after 200 and 300 procedures, respectively. By moving average method, endoscopists reached a mean ADR of 20% at 216 and 261 procedures over blocks of 50 and 100 procedures, respectively. The total number of procedures, number of daily procedures, patient age and gender, bowel preparation, sedation, and diverticulosis were significantly associated with adenoma detection. CONCLUSIONS: This is the first study to investigate the learning curve of ADR for those well-trained endoscopists who have a CIR ≥ 90% and start to perform colonoscopy independently. Two hundred procedures might be an optimal number required to reach an ADR ≥ 20%.

The Impact of Sedation on Adenoma Detection Rate and Cecal Intubation Rate in Colonoscopy.

PURPOSE: To explore the effect of sedation on the quality of colonoscopy. METHODS: The data collected from the Digestive Endoscopy Center of Shanghai Tongji Hospital from March 2012 to June 2019 were retrospectively analyzed. The rate of sedation and quality metrics of colonoscopy such as adenoma detection rate (ADR) and cecal intubation rate (CIR) were calculated. The logistic regression model was used to explore the relationship between sedation and quality metrics of colonoscopy. The interaction effects between experience of endoscopists and sedation on quality of colonoscopy was also investigated in subgroups stratified by total number of colonoscopies during career using the logistic regression model. RESULTS: A total of 63,417 colonoscopies including 11,417 colonoscopies without sedation and 52,000 colonoscopies with sedation were enrolled in our study. The proportion of colonoscopy with sedation was 82.0%. The ADR and CIR were all significantly higher in cases with sedation compared with cases without sedation (ADR, 22.5% vs. 17.0%, p < 0.001; CIR, 94.7% vs. 91.2%, p < 0.001). Multivariate analysis showed that the sedation was an independent factor associated with adenoma detection (OR = 1.448, 95% CI: 1.372~1.529, p < 0.001) and cecal intubation (OR = 1.560, 95% CI: 1.446~1.683, p < 0.001). A total of 14 endoscopists with complete colonoscopy data in our database and corresponding 20,949 colonoscopies data were enrolled for further analysis. The logistic regression model yielded a similar result that sedation was an independent factor on adenoma detection and cecal intubation when the factor, experience of endoscopists, was also entered into the model as a confounder (adenoma detection, OR = 1.408, 95% CI: 1.333~1.487, p < 0.001; cecal intubation, OR = 1.601, 95% CI: 1.482-1.729, p < 0.001). CONCLUSION: Colonoscopy with sedation has a positive effect on ADR and CIR in all endoscopists with different experience of colonoscopy, which makes the quality of colonoscopy better.

Amine-catalyzed (3+n) annulations of 2-(acetoxymethyl)buta-2,3-dienoates with 1,n-bisnucleophiles (n = 3-5).

A tertiary amine-catalyzed formal (3+n) annulation of 2-(acetoxymethyl)buta-2,3-dienoate with 1,n-binucleophiles has been developed, which provides a facile entry to heterocyclic compounds. The mechanism, involving tandem S(N)2'-S(N)2' substitution and Michael addition, has also been established.

2-(Acetoxymethyl)buta-2,3-dienoate, a versatile 1,4-biselectrophile for phosphine-catalyzed (4 + n) annulations with 1,n-Bisnucleophiles (n = 1, 2).

A novel PPh(3)-catalyzed (4 + n) annulation of 2-(acetoxymethyl)buta-2,3-dienoates 1c-e with 1,n-bisnucleophiles (n = 1, 2) has been developed to provide a facile synthetic method for cyclopentene and 1,2,3,6-tetrahydropyridazine derivatives. The acetate group of 2-(acetoxymethyl)buta-2,3-dienoate is crucial for the formation of 1,4-biselectrophilic intermediate C, which is recognized to be a 1,4-biselectrophile that can react with 1,n-bisnucleophiles. Deuterium studies also suggest that the reaction pathway involves a proton-transfer process.

PPh3-catalyzed reactions of alkyl propiolates with N-tosylimines: a facile synthesis of alkyl 2-[aryl(tosylimino)methyl]acrylate and an insight into the reaction mechanism.

A new PPh(3)-catalyzed synthesis of alkyl 2-[aryl(tosylimino)methyl]acrylates from propiolate and N-tosylimine has been developed. Deuterium-labelling experiments show that the reaction mechanism involves several hydrogen-transfer processes, which are not the turnover-limiting step and strongly rely on the nature of the reaction media. The stable phosphonium-enamine zwitterion, which was proven to play an important role in the catalytic cycle, has been isolated and characterised by X-ray analysis.

PPh3-catalyzed [2 + 2 + 2] and [4 + 2] annulations: synthesis of highly substituted 1,2-dihydropyridines (DHPs).

PPh(3)-catalyzed [2 + 2 + 2] annulations between two units of an activated terminal alkyne and one unit of an aryl N-tosylimine have been developed to provide a synthetic method for highly substituted dihydropyridines. On the basis of the mechanism of the [2 + 2 + 2] annulation, PPh(3)-catalyzed [4 + 2] annulations have also been discovered.