AIM:To determine which patients might benefit most from retrograde viewing during colonoscopy through subset analysis of randomized,controlled trial data.METHODS:The Third Eye Retroscope Randomized Clinical Evaluation...AIM:To determine which patients might benefit most from retrograde viewing during colonoscopy through subset analysis of randomized,controlled trial data.METHODS:The Third Eye Retroscope Randomized Clinical Evaluation(TERRACE) was a randomized,controlled,multicenter trial designed to evaluate the efficacy of a retrograde-viewing auxiliary imaging device that is used during colonoscopy to provide a second video image which allows viewing of areas on the proximal aspect of haustral folds and flexures that are difficult to see with the colonoscope's forward view.We performed a post-hoc analysis of the TERRACE data to determine whether certain subsets of the patient population would gain more benefit than others from use of the device.Subjects were patients scheduled for colonoscopy for screening,surveillance or diagnostic workup,and each underwent same-day tandem examinations with standard colonoscopy(SC) and Third Eye colonoscopy(TEC),randomized to SC followed by TEC or vice versa.RESULTS:Indication for colonoscopy was screening in 176/345 subjects(51.0%),surveillance after previous polypectomy in 87(25.2%) and diagnostic workup in 82(23.8%).In 4 subjects no indication was specified.Previously reported overall results had shown a net additional adenoma detection rate(ADR) with TEC of 23.2% compared to SC.Relative risk(RR) of missing adenomas with SC vs TEC as the initial procedure was 1.92(P = 0.029).Post-hoc subset analysis shows additional ADRs for TEC compared to SC were 4.4% for screening,35.7% for surveillance,55.4% for diagnostic and 40.7% for surveillance and diagnostic combined.The RR of missing adenomas with SC vs TEC was 1.11(P = 0.815) for screening,3.15(P = 0.014) for surveillance,8.64(P = 0.039) for diagnostic and 3.34(P = 0.003) for surveillance and diagnostic combined.Although a multivariate Poisson regression suggested gender as a possibly significant factor,subset analysis showed that the difference between genders was not statistically significant.Age,bowel prep quality and withdrawal time did not significantly affect the RR of missing adenomas with SC vs TEC.Mean sizes of adenomas detected with TEC and SC were similar at 0.59 cm and 0.56 cm,respectively(P = NS).CONCLUSION:TEC allows detection of significantly more adenomas compared to SC in patients undergoing surveillance or diagnostic workup,but not in screening patients(ClinicalTrials.gov Identifier:NCT01044732).展开更多
Hospital volume is regarded amongst many in the medical community as an important quality metric. This is especially true in more complicated and less commonly performed procedures such as structural heart disease int...Hospital volume is regarded amongst many in the medical community as an important quality metric. This is especially true in more complicated and less commonly performed procedures such as structural heart disease interventions. Seminal work on hospital volume relationships was done by Luft et al more than 4 decades ago, when they demonstrated that hospitals performing > 200 surgical procedures a year had 25%-41% lower mortality than those performing fewer procedures. Numerous volume-outcome studies have since been done for varied surgical procedures. An old adage "practice makes perfect" indicating superior operator and institutional experience at higher volume hospitals is believed to primarily contribute to the volume outcome relationship. Compelling evidence from a slew of recent publications has also highlighted the role of hospital volume in predicting superior post-procedural outcomes following structural heart disease interventions. These included transcatheter aortic valve repair, transcatheter mitral valve repair, septal ablation and septal myectomy for hypertrophic obstructive cardiomyopathy, left atrial appendage closure and atrial septal defect/patent foramen ovale closure. This is especially important since these structural heart interventions are relatively complex with evolving technology and a steep learning curve. The benefit was demonstrated both in lower mortality and complications as well as better economics in terms of lower length of stay and hospitalization costs seen at high volume centers. We present an overview of the available literature that underscores the importance of hospital volume in complex structural heart disease interventions.展开更多
This paper attempts to find out the distributed server-based dynamic spectrum allocation (DSA) within liberalized spectrum sharing regulation concept as an alternative to existing regulation based on fixed frequency s...This paper attempts to find out the distributed server-based dynamic spectrum allocation (DSA) within liberalized spectrum sharing regulation concept as an alternative to existing regulation based on fixed frequency spectrum allocation schemes towards development of cognitive radio for coverage-based analogy. The present study investigates a scenario where a block of spectrum is shared among four different kinds of exemplary air interface standards i.e., GSM, CDMA, UMTS and WiMAX. It is assumed to offer traffic in an equally likely manner, which occupy four different sizes of channel bandwidths for different air interfaces from a common pooled spectrum. Four different approaches for spectrum pooling at the instance of spectrum crunch in the designated block are considered, viz. channel occupancy through random search, existing regulation based on fixed spectrum allocation (FSA), FSA random and channel occupancy through Genetic Algorithm (GA) based optimized mechanism to achieve desired grade of service (GoS). The comparisons of all the approaches are presented in this paper for different air interfaces which shows up to 55% improvement in GoS for all types of air interfaces with GA-based approach in comparison to existing regulations.展开更多
基金Supported by A grant from Avantis Medical Systems,in part
文摘AIM:To determine which patients might benefit most from retrograde viewing during colonoscopy through subset analysis of randomized,controlled trial data.METHODS:The Third Eye Retroscope Randomized Clinical Evaluation(TERRACE) was a randomized,controlled,multicenter trial designed to evaluate the efficacy of a retrograde-viewing auxiliary imaging device that is used during colonoscopy to provide a second video image which allows viewing of areas on the proximal aspect of haustral folds and flexures that are difficult to see with the colonoscope's forward view.We performed a post-hoc analysis of the TERRACE data to determine whether certain subsets of the patient population would gain more benefit than others from use of the device.Subjects were patients scheduled for colonoscopy for screening,surveillance or diagnostic workup,and each underwent same-day tandem examinations with standard colonoscopy(SC) and Third Eye colonoscopy(TEC),randomized to SC followed by TEC or vice versa.RESULTS:Indication for colonoscopy was screening in 176/345 subjects(51.0%),surveillance after previous polypectomy in 87(25.2%) and diagnostic workup in 82(23.8%).In 4 subjects no indication was specified.Previously reported overall results had shown a net additional adenoma detection rate(ADR) with TEC of 23.2% compared to SC.Relative risk(RR) of missing adenomas with SC vs TEC as the initial procedure was 1.92(P = 0.029).Post-hoc subset analysis shows additional ADRs for TEC compared to SC were 4.4% for screening,35.7% for surveillance,55.4% for diagnostic and 40.7% for surveillance and diagnostic combined.The RR of missing adenomas with SC vs TEC was 1.11(P = 0.815) for screening,3.15(P = 0.014) for surveillance,8.64(P = 0.039) for diagnostic and 3.34(P = 0.003) for surveillance and diagnostic combined.Although a multivariate Poisson regression suggested gender as a possibly significant factor,subset analysis showed that the difference between genders was not statistically significant.Age,bowel prep quality and withdrawal time did not significantly affect the RR of missing adenomas with SC vs TEC.Mean sizes of adenomas detected with TEC and SC were similar at 0.59 cm and 0.56 cm,respectively(P = NS).CONCLUSION:TEC allows detection of significantly more adenomas compared to SC in patients undergoing surveillance or diagnostic workup,but not in screening patients(ClinicalTrials.gov Identifier:NCT01044732).
文摘Hospital volume is regarded amongst many in the medical community as an important quality metric. This is especially true in more complicated and less commonly performed procedures such as structural heart disease interventions. Seminal work on hospital volume relationships was done by Luft et al more than 4 decades ago, when they demonstrated that hospitals performing > 200 surgical procedures a year had 25%-41% lower mortality than those performing fewer procedures. Numerous volume-outcome studies have since been done for varied surgical procedures. An old adage "practice makes perfect" indicating superior operator and institutional experience at higher volume hospitals is believed to primarily contribute to the volume outcome relationship. Compelling evidence from a slew of recent publications has also highlighted the role of hospital volume in predicting superior post-procedural outcomes following structural heart disease interventions. These included transcatheter aortic valve repair, transcatheter mitral valve repair, septal ablation and septal myectomy for hypertrophic obstructive cardiomyopathy, left atrial appendage closure and atrial septal defect/patent foramen ovale closure. This is especially important since these structural heart interventions are relatively complex with evolving technology and a steep learning curve. The benefit was demonstrated both in lower mortality and complications as well as better economics in terms of lower length of stay and hospitalization costs seen at high volume centers. We present an overview of the available literature that underscores the importance of hospital volume in complex structural heart disease interventions.
文摘This paper attempts to find out the distributed server-based dynamic spectrum allocation (DSA) within liberalized spectrum sharing regulation concept as an alternative to existing regulation based on fixed frequency spectrum allocation schemes towards development of cognitive radio for coverage-based analogy. The present study investigates a scenario where a block of spectrum is shared among four different kinds of exemplary air interface standards i.e., GSM, CDMA, UMTS and WiMAX. It is assumed to offer traffic in an equally likely manner, which occupy four different sizes of channel bandwidths for different air interfaces from a common pooled spectrum. Four different approaches for spectrum pooling at the instance of spectrum crunch in the designated block are considered, viz. channel occupancy through random search, existing regulation based on fixed spectrum allocation (FSA), FSA random and channel occupancy through Genetic Algorithm (GA) based optimized mechanism to achieve desired grade of service (GoS). The comparisons of all the approaches are presented in this paper for different air interfaces which shows up to 55% improvement in GoS for all types of air interfaces with GA-based approach in comparison to existing regulations.
