The synergistic role of virtual coaching with simulation-based mastery learning for upper endoscopy

Introduction

Our simulation-based mastery learning (SBML) curriculum, delivered in person, has been shown to successfully train novices in structured esophagogastroduodenoscopy (EGD). SBML with virtual coaching (VC) has the potential to improve the effectiveness and efficiency of endoscopy training and expand access to trainees from around the world. We share our observations conducting an EGD training course using SBML with VC.

Methods

We conducted a 1-week virtual SBML course for novice trainees across seven academic centers in the USA and Asia. The cognitive component was delivered using an online learning platform. For technical skills, a virtual coach supervised hands-on training and local coaches provided assistance when needed. At the end of training, an independent rater assessed simulation-based performance using a validated assessment tool. We assessed the clinical performance of 30 EGDs using the ASGE Assessment of Competency in Endoscopy tool. We compared the trainees' scores to our cohort trained using in-person SBML training using non-inferiority t-tests.

Results

We enrolled 21 novice trainees (mean age: 30.8 ± 3.6 years; female: 52%). For tip deflection, the trainees reached the minimum passing standard after 31 ± 29 runs and mastery after 52 ± 37 runs. For structured EGD, the average score for the overall exam was 4.6 ± 0.6, similar to the in-person cohort (4.7 ± 0.5, p = 0.49). The knowledge-based assessment was also comparable (virtual coaching: 81.9 ± 0.1; direct coaching: 78.3 ± 0.1; p = 0.385). Over time, our novice trainees reached clinical competence at a similar rate to our historical in-person control.

Conclusions

VC appears feasible and effective for training novice gastroenterology trainees. VC allowed us to scale our SBML course, expand access to experts, and administer SBML simultaneously across different sites at the highest standards.

Alliance A022101: A Pragmatic Randomized Phase III Trial Evaluating Total Ablative Therapy for Patients with Limited Metastatic Colorectal Cancer - Evaluating Radiation, Ablation and Surgery (ERASur)

PURPOSE/OBJECTIVE(S)

For patients with oligometastatic colorectal cancer (CRC), aggressive local therapy of isolated metastases, particularly in the liver, has been associated with long-term progression-free survival and overall survival (OS) primarily based on retrospective evidence. However, in patients with limited metastatic CRC that is deemed inoperable or those with additional disease outside of the liver or lungs, the role of local ablative therapies, including microwave ablation (MWA) and stereotactic body radiation therapy (SBRT), to render patients disease free is less clear. Further, despite the long history of treating oligometastatic CRC with local therapy, which is provider biased and not evidence based, questions remain regarding the benefit of extending the paradigm of metastatic directed therapy to patients with more extensive disease. This trial seeks to use a pragmatic multimodality approach that mirrors the current clinical dilemma. This study is designed to evaluate the safety and efficacy of adding total ablative therapy (TAT) of all sites of disease to standard of care systemic treatment in those with limited metastatic CRC.

MATERIALS/METHODS

A022101 is a National Clinical Trials Network randomized phase III study planned to enroll 364 patients with newly diagnosed metastatic CRC (BRAF wild-type, microsatellite stable) with 4 or fewer sites of metastatic disease on baseline imaging. Liver-only metastatic disease is not permitted, and lesions must be amenable to any combination of surgical resection, MWA, and/or SBRT with SBRT required for at least one lesion. Patients receive first-line systemic therapy for 4-6 months and are then randomized 1:1, stratified by number of metastatic organ sites (1-2 vs. 3-4), timing of metastatic disease diagnosis (de novo vs. secondary), and presence of metastatic disease outside the liver and lungs in at least one site. Patients in Arm 1 will receive TAT which consists of treatment of all metastatic sites with SBRT ± MWA ± surgical resection followed by standard of care systemic therapy. Patients in Arm 2 will continue with standard of care systemic therapy alone. The primary endpoint is OS. Secondary endpoints include event-free survival, treatment-related toxicities, and local recurrence with exploratory biomarker analyses. The study needs 346 evaluable patients combined in the 2 arms to demonstrate an improvement in OS with a hazard ratio of 0.7 to provide 80% power with a one-sided alpha of 5%. The trial utilizes a group sequential design with two interim analyses (25% and 50% of events) for futility.

RESULTS

The trial activated in January 2023.

CONCLUSION

Recruitment is ongoing.

American Society for Gastrointestinal Endoscopy guideline on the role of ergonomics for prevention of endoscopy-related injury: summary and recommendations

This clinical practice guideline from the American Society for Gastrointestinal Endoscopy provides an evidence-based approach to strategies to prevent endoscopy-related injury (ERI) in GI endoscopists. It is accompanied by the article subtitled "Methodology and Review of Evidence," which provides a detailed account of the methodology used for the evidence review. This document was developed using the Grading of Recommendations Assessment, Development and Evaluation framework. The guideline estimates the rates, sites, and predictors of ERI. Additionally, it addresses the role of ergonomics training, microbreaks and macrobreaks, monitor and table positions, antifatigue mats, and use of ancillary devices in decreasing the risk of ERI. We recommend formal ergonomics education and neutral posture during the performance of endoscopy, achieved through adjustable monitor and optimal procedure table position, to reduce the risk of ERI. We suggest taking microbreaks and scheduled macrobreaks and using antifatigue mats during procedures to prevent ERI. We suggest the use of ancillary devices in those with risk factors predisposing them to ERI.

Varied Trainee Competence in Cold Snare Polypectomy: Results of the COMPLETE Randomized Controlled Trial

INTRODUCTION

Cold snare polypectomy (CSP) is strongly recommended as the optimal technique for the complete removal of small polyps. Though significant variability in polypectomy technique and quality has been established, the learning curve and impact of targeted training on CSP are unknown. Video feedback has shown promise as an effective pedagogy to improve performance among surgical trainees. We aimed to compare CSP performance between trainees who received video-based feedback and those who received conventional apprentice-based concurrent feedback. We hypothesized that video-based feedback would accelerate competence.

METHODS

We conducted a single-blinded, randomized controlled trial on competence for CSP of polyps <1 cm, comparing video-based feedback with conventional feedback. We randomly assigned deidentified consecutively recorded CSP videos to blinded raters to assess using the CSP Assessment Tool. We shared cumulative sum learning curves every 25 CSP with each trainee. The video feedback trainees also received biweekly individualized terminal feedback. Control trainees received conventional feedback during colonoscopy. The primary outcome was CSP competence. We also assessed competence across domains and change over polypectomy volume.

RESULTS

We enrolled and randomized 22 trainees, 12 to video-based feedback and 10 to conventional feedback, and evaluated 2,339 CSP. The learning curve was long; 2 trainees (16.7%) in the video feedback achieved competence, after a mean of 135 polyps, and no one in the control ( P = 0.481) achieved competence. Overall and in all steps of CSP, a higher percentage of the video feedback group met competence, increasing 3% every 20 CSP ( P = 0.0004).

DISCUSSION

Video feedback aided trainees to competence in CSP. However, the learning curve was long. Our findings strongly suggest that current training methods are not sufficient to support trainees to competency by the completion of their fellowship programs. The impact of new training methods, such as simulation-based mastery learning, should be assessed to determine whether such methods can result in achievement of competence at a faster rate; ClinicalTrials.gov : NCT03115008.

Does Manual Abdominal Pressure During Colonoscopy Put Endoscopy Staff and Patients at Risk? Experiences of Endoscopy Nurses and Technicians

Endoscopy staff suffer work-related musculoskeletal disorders at a rate greater than or comparable to nurses and technicians in other subspecialities, which may be attributable to the widespread use of manual pressure and repositioning during colonoscopy. In addition to negatively impacting staff health and job performance, colonoscopy-related musculoskeletal disorder injuries may also signal potential risks to patient safety. To assess the prevalence of staff injury and perceived patient harm relating to the use of manual pressure and repositioning techniques during colonoscopy, 185 attendees of a recent national meeting of the Society of Gastroenterology Nurses and Associates were asked to recall experiencing injuries to themselves or observing injuries to other staff or patients during colonoscopy. A majority of respondents (84.9%, n = 157) reported either experiencing or observing staff injury, whereas 25.9% ( n = 48) reported observing patient complications. Among respondents who perform manual repositioning and apply manual pressure during colonoscopy (57.3%, n = 106), 85.8% ( n = 91) reported experiencing musculoskeletal disorders from performing these tasks; 81.1% ( n = 150) reported no awareness of colonoscopy-specific ergonomics policies at their facility. Results highlight the relationship between the physical job requirements of endoscopy nurses and technicians, staff musculoskeletal disorders, and patient complications, and suggest that implementation of staff safety protocols may benefit patients as well as endoscopy staff.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Prevalence of Advanced Colorectal Neoplasia in Veterans: Effects of Age, Sex, and Race/Ethnicity

GOAL

We sought to quantify the independent effects of age, sex, and race/ethnicity on risk of colorectal cancer (CRC) and advanced neoplasia (AN) in Veterans.

STUDY

We conducted a retrospective, cross-sectional study of Veterans aged 40 to 80 years who had diagnostic or screening colonoscopy between 2002 and 2009 from 1 of 14 Veterans Affairs Medical Centers. Natural language processing identified the most advanced finding and location (proximal, distal). Logistic regression was used to examine the adjusted, independent effects of age, sex, and race, both overall and in screening and diagnostic subgroups.

RESULTS

Among 90,598 Veterans [mean (SD) age 61.7 (9.4) y, 5.2% (n=4673) were women], CRC and AN prevalence was 1.3% (n=1171) and 8.9% (n=8081), respectively. Adjusted CRC risk was higher for diagnostic versus screening colonoscopy [odds ratio (OR)=3.79; 95% confidence interval (CI), 3.19-4.50], increased with age, was numerically (but not statistically) higher for men overall (OR=1.53; 95% CI, 0.97-2.39) and in the screening subgroup (OR=2.24; 95% CI, 0.71-7.05), and was higher overall for Blacks and Hispanics, but not in screening. AN prevalence increased with age, and was present in 9.2% of men and 3.9% of women [adjusted OR=1.90; 95% CI, 1.60-2.25]. AN risk was 11% higher in Blacks than in Whites overall (OR=1.11; 95% CI, 1.04-1.20), was no different in screening, and was lower in Hispanics (OR=0.74; 95% CI, 0.55-0.98). Women had more proximal CRC (63% vs. 39% for men; P=0.03), but there was no difference in proximal AN (38.3% for both genders).

CONCLUSIONS

Age and race were associated with AN and CRC prevalence. Blacks had a higher overall prevalence of both CRC and AN, but not among screenings. Men had increased risk for AN, while women had a higher proportion of proximal CRC. These findings may be used to tailor when and how Veterans are screened for CRC.

Adenoma Detection Rate (ADR) Irrespective of Indication Is Comparable to Screening ADR: Implications for Quality Monitoring

BACKGROUND & AIMS

Adenoma detection rate (ADR) is a key measure of colonoscopy quality. However, efficient measurement of ADR can be challenging because many colonoscopies are performed for non-screening purposes. Measuring ADR without being restricted to screening indication may likely facilitate more widespread implementation of quality monitoring. We hypothesized that the ADR for all colonoscopies, irrespective of the indication, would be equivalent to the ADR for screening colonoscopies.

METHODS

We reviewed consecutive colonoscopies at two Veterans Affairs centers performed by 21 endoscopists over 6 months in 2015. We calculated the ADR for screening exams, non-screening (surveillance and diagnostic) exams, and all exams (irrespective of indication), correcting for within-endoscopist correlation. We then performed simulation modeling to calculate the ADRs under 16 hypothetical scenarios of various indication distributions. We simulated 100,000 trials with 3,000 participants, randomly assigned indication (screening, surveillance, diagnostic, and FIT+) from a multinomial distribution, randomly drew adenoma using the observed ADRs per indication, and calculated 95% confidence intervals of the mean differences in ADR of screening and non-screening indications.

RESULTS

Among 2628 colonoscopies performed by 21 gastroenterologists, the indication was screening in 28.9%, surveillance in 48.2% and diagnostic in 22.9%. There was no significant difference in the ADR, 50% (95%CI: 45-56%) for all colonoscopies vs 49% (95%CI: 43-56%) for screening exams (p=.55). ADRs were 56% for surveillance and 38% for diagnostic exams. In our simulation modeling, only one out of 16 scenarios (screening 10%, surveillance 70%, diagnostic 10% and FIT+ 10%) resulted in a significant difference between the calculated ADRs for screening and non-screening indications.

CONCLUSIONS

In our study, the overall ADR computed from all colonoscopies was not significantly different than the conventional ADR based on screening colonoscopies. Assessing ADR for colonoscopy irrespective of indication may be adequate for quality monitoring, and could facilitate the implementation of quality measurement and reporting. Future prospective studies should evaluate the validity of using overall ADR for quality reporting in other jurisdictions before adopting this method in clinical practice.

Effect of individualized feedback on learning curves in EGD and colonoscopy: a cluster randomized controlled trial

BACKGROUND AND AIMS

Gastroenterology fellowships need to ensure that trainees achieve competence in upper endoscopy (EGD) and colonoscopy. Because the impact of structured feedback remains unknown in endoscopy training, this study compared the effect of structured feedback with standard feedback on trainee learning curves for EGD and colonoscopy.

METHODS

In this multicenter, cluster, randomized controlled trial, trainees received either individualized quarterly learning curves or feedback standard to their fellowship. Assessment was performed in all trainees using the Assessment of Competency in Endoscopy tool on 5 consecutive procedures after every 25 EGDs and colonoscopies. Individual learning curves were created using cumulative sum (CUSUM) analysis. The primary outcome was the mean CUSUM score in overall technical and overall cognitive skills.

RESULTS

In all, 13 programs including 132 trainees participated. The intervention arm (6 programs, 51 trainees) contributed 558 EGD and 600 colonoscopy assessments. The control arm (7 programs, 81 trainees) provided 305 EGD and 468 colonoscopy assessments. For EGD, the intervention arm (-.7 [standard deviation {SD}, 1.3]) had a superior mean CUSUM score in overall cognitive skills compared with the control arm (1.6 [SD, .8], P = .03) but not in overall technical skills (intervention, -.26 [SD, 1.4]; control, 1.76 [SD, .7]; P = .06). For colonoscopy, no differences were found between the 2 arms in overall cognitive skills (intervention, -.7 [SD, 1.3]; control, .7 [SD, 1.3]; P = .95) or overall technical skills (intervention, .1 [SD, 1.5]; control, -.1 [SD, 1.5]; P = .77).

CONCLUSIONS

Quarterly feedback in the form of individualized learning curves did not affect learning curves for EGD and colonoscopy in a clinically meaningful manner. (Clinical trial registration number: NCT02891304.).

Impact of observational training on endoscopic mucosal resection outcomes and competency for large colorectal polyps: single endoscopist experience

Background and study aims  Endoscopic mucosal resection (EMR) is standard treatment for large colorectal polyps. However, it is a specialized technique with limited data on the effectiveness of training methods to acquire this skill. The aim of this study was to evaluate the impact of observational training on EMR outcomes and competency in an early-stage endoscopist. Patients and methods  A single endoscopist completed comprehensive EMR training, which included knowledge acquisition and direct observation of EMR cases, and proctored supervision, during the third year of gastroenterology fellowship. After training, EMR was independently attempted on 142 consecutive, large (i. e., ≥ 20 mm), non-pedunculated colorectal polyps between July 2014 and December 2017 (mean age 61.7 years; mean polyp size 30.4 mm; en-bloc resection 55 %). Surveillance colonoscopy for evaluation of residual neoplasia was available for 86 % of the cases. Three primary outcomes were evaluated: endoscopic assessment of complete resection, rate of adverse events (AEs), and rate of residual neoplasia on surveillance colonoscopy. Results  Complete endoscopic resection was achieved in 93 % of cases, the rates of AEs and residual neoplasia were 7.8 % and 7.3 %, respectively. The rate of complete resection remained stable (at 85 % or greater) with increasing experience while rates of AEs and residual neoplasia peaked and decreased after 60 cases. Conclusions  An early-stage endoscopist can acquire the skills to perform effective EMR after completing observational training. At least 60 independent EMRs for large colorectal polyps were required to achieve a plateau for clinically meaningful outcomes.

Development and validation of a video-based cold snare polypectomy assessment tool (with videos)

BACKGROUND AND AIMS

Polyps <1 cm are the most commonly found polyps during colonoscopy. Cold snare removal is preferred given the significantly higher rate of incomplete resection associated with piecemeal biopsy forceps resection. There are currently no standardized tools to assess competence in cold snare polypectomy. This study aimed to develop and validate a cold snare polypectomy assessment tool (CSPAT).

METHODS

Experts in cold snare polypectomy used a Delphi method to develop the CSPAT. Metrics with a greater than 85% agreement as being "important" or "very important" were included in the CSPAT. The tool included evaluation of polyp inspection, positioning, appropriate ensnarement of tissue to ensure a rim of normal tissue, tissue retrieval, and postpolypectomy site inspection. Experts in cold snare polypectomy used the CSPAT to evaluate preselected videos that were previously evaluated using the Direct Observation of Polypectomy Skills (DOPyS) tool. Interobserver agreement was evaluated. CSPAT scores were compared with DOPyS scores to assess content validity.

RESULTS

Sixteen experts developed the 12-item CSPAT, and 13 experts reviewed 55 videos. There was a moderate degree of agreement in 10 metrics (κ = .52-.59) and a substantial degree of agreement (κ = .61-.63) in the other 2. There was a strong correlation between the mean of individual metrics 1 to 12 compared with the global competence assessment (ρ = .88, P < .001). There was a moderate correlation between the average overall DOPyS score and the overall CSPAT competence score (ρ = .56, P < .001).

CONCLUSIONS

We have developed and validated a customized CSPAT that can be easily applied to video-based assessments to assess competence in training and among practicing endoscopists.

Endoscopic Surveillance in Long-standing Colitis

OPINION STATEMENT

There is a relative increase in the risk of colon cancer in patients with inflammatory bowel disease (IBD) affecting the colon, and endoscopic surveillance is advocated to mitigate this risk. The current standard practice is to survey this high-risk patient population using colonoscopy. Chromoendoscopy with targeted biopsies has emerged as the colonoscopy modality recommended by the major societies to optimize dysplasia detection. Studies over the past year support the improved yield from targeted as compared to random biopsies and improved dysplasia detection from chromoendoscopy as compared to white light endoscopy. Ongoing efforts should focus on the implementation of chromoendoscopy as the primary modality for colorectal cancer surveillance in IBD. Our review will describe current status and provide an update on the recent literature on surveillance colonoscopy in patients with IBD.

Multi-center colonoscopy quality measurement utilizing natural language processing

BACKGROUND

An accurate system for tracking of colonoscopy quality and surveillance intervals could improve the effectiveness and cost-effectiveness of colorectal cancer (CRC) screening and surveillance. The purpose of this study was to create and test such a system across multiple institutions utilizing natural language processing (NLP).

METHODS

From 42,569 colonoscopies with pathology records from 13 centers, we randomly sampled 750 paired reports. We trained (n=250) and tested (n=500) an NLP-based program with 19 measurements that encompass colonoscopy quality measures and surveillance interval determination, using blinded, paired, annotated expert manual review as the reference standard. The remaining 41,819 nonannotated documents were processed through the NLP system without manual review to assess performance consistency. The primary outcome was system accuracy across the 19 measures.

RESULTS

A total of 176 (23.5%) documents with 252 (1.8%) discrepant content points resulted from paired annotation. Error rate within the 500 test documents was 31.2% for NLP and 25.4% for the paired annotators (P=0.001). At the content point level within the test set, the error rate was 3.5% for NLP and 1.9% for the paired annotators (P=0.04). When eight vaguely worded documents were removed, 125 of 492 (25.4%) were incorrect by NLP and 104 of 492 (21.1%) by the initial annotator (P=0.07). Rates of pathologic findings calculated from NLP were similar to those calculated by annotation for the majority of measurements. Test set accuracy was 99.6% for CRC, 95% for advanced adenoma, 94.6% for nonadvanced adenoma, 99.8% for advanced sessile serrated polyps, 99.2% for nonadvanced sessile serrated polyps, 96.8% for large hyperplastic polyps, and 96.0% for small hyperplastic polyps. Lesion location showed high accuracy (87.0-99.8%). Accuracy for number of adenomas was 92%.

CONCLUSIONS

NLP can accurately report adenoma detection rate and the components for determining guideline-adherent colonoscopy surveillance intervals across multiple sites that utilize different methods for reporting colonoscopy findings.

Recurrence of subsquamous dysplasia and carcinoma after successful endoscopic and radiofrequency ablation therapy for dysplastic Barrett's esophagus

Barrett's esophagus with dysplasia is commonly treated with radiofrequency ablation (RFA). Despite its effectiveness, a concern of any ablative technique is the development of subsquamous intestinal metaplasia, which could have potential for future neoplastic progression. To date, 34 cases of subsquamous neoplasia have been described in the literature after various ablation therapies. However, only three cases of subsquamous neoplasia have been reported after successful RFA treatment of dysplastic Barrett's esophagus. In this case series, we report on four additional cases of subsquamous neoplasia detected after successful endoscopic resection and RFA for neoplastic and dysplastic Barrett's esophagus. All four patients were treated successfully with endoscopic resection of their recurrent subsquamous neoplastic and dysplastic lesions. This case series highlights the need for continued surveillance following successful treatment of dysplastic Barrett's esophagus with RFA.

Clinical features of acute coronary syndromes in patients with human immunodeficiency virus infection

BACKGROUND

Patients with HIV infection exhibit increased rates of coronary events; however, the clinical features of acute coronary syndromes (ACS) in HIV-infected patients have not been well defined.

METHODS AND RESULTS

Between 1993 and 2003, 68 HIV-infected patients were hospitalized with ACS. We compared the clinical features and outcome of these patients with those of 68 randomly selected control patients with ACS without HIV. HIV patients were on average more than a decade younger than controls and more likely to be male and current smokers and to have low HDL cholesterol. They were less likely than controls to have diabetes or hyperlipidemia, and their TIMI (Thrombolysis In Myocardial Infarction) risk scores on admission were significantly lower. At coronary angiography, the number of vessels with >50% stenosis was 1.3+/-1.0 in HIV patients and 1.9+/-1.2 in controls (P=0.007). Restenosis developed in 15 of 29 HIV patients who underwent percutaneous coronary intervention compared with 3 of 21 controls (52% versus 14%, P=0.006).

CONCLUSIONS

HIV patients with ACS are younger and more likely to be males and current smokers and to have low HDL cholesterol levels compared with other ACS patients. Their TIMI risk scores are lower, and they are more likely to have single-vessel disease; however, their restenosis rates after percutaneous coronary intervention are unexpectedly high.