Systematic review of carotid artery procedures and the volume-outcome relationship in Europe

Surgical Specialty Impacts Quality of Operative Training in Carotid Endarterectomy

BACKGROUND

Carotid endarterectomy (CEA) is currently performed by multiple surgical specialties. The impact of surgical specialty and operative volume on post-CEA outcomes has been well described. However, it is unclear whether trainees of different surgical specialties have similar quality of operative training.

METHODS

Data from Accreditation Council for Graduate Medical Education annual reports were collected and compared between graduating vascular surgery (VS) residents, VS fellows, and neurological surgery (NS) residents. Only cases reported as chief/senior/lead resident, surgeon junior, or surgeon fellow were included in analysis. Linear regression analysis was utilized to evaluate trends in case-mix and volume.

RESULTS

From 2013 to 2022, total CEA case volume was higher among VS residents and fellows, compared to NS residents (52.8 ± 0.8 vs. 44.3 ± 1.4 vs. 12.9 ± 0.6, P < 0.0001). Additionally, VS residents and fellows performed other carotid operations including transfemoral or transcarotid artery stenting (11.1 ± 0.9 vs. 11.2 ± 0.8 vs. 0), carotid body tumor resection (0.7 ± 0.1 vs. 0.7 ± 0.0 vs. 0), and extracranial cervical bypass (6.7 ± 0.3 vs. 6.3 ± 0.3 vs. 0) that were not reported by the NS resident cohort (P < 0.0001 each). On linear regression analysis, total CEA procedures did not change for VS residents (R2 = 0.03, P = 0.62), decreased for VS fellows (-1.29 cases/yr, R2 = 0.75, P < 0.0001), and decreased among NS residents (-0.41 cases/yr, R2 = 0.44, P = 0.01) over the study period.

CONCLUSIONS

Although residents of multiple surgical specialties are trained in CEA, vascular training offers significantly greater numbers and diversity of extracranial carotid cases. It also appears that CEA volume is decreasing among neurosurgical trainees. In light of recent reports on the volume-outcome effect in carotid surgery, these data may have implications for future practice patterns in the domain of extracranial carotid artery disease.

Assessing the volume-outcome relationship of carotid artery stenting in nationwide administrative data: a challenge of patient population bias

BACKGROUND

Studies have shown an association between surgical treatment volume and improved quality metrics. This study evaluated nationwide results in carotid artery stenting (CAS) procedural readmission rates, costs, and length of stay based on hospital treatment volume.

METHODS

We used the Nationwide Readmissions Database for carotid stenosis from 2010 to 2015. Patients receiving CAS were matched based on demographics, illness severity, and relevant comorbidities. Patients were matched 1:1 between low- and high-volume centers using a non-parametric preprocessing matching program to adjust for parametric causal inferences. Nearest-neighbor propensity score matching was performed using logit distance.

RESULTS

Low- and high-volume centers admitted a mean (SD) of 4.68 (3.79) and 25.10 (16.86) patients undergoing CAS per hospital, respectively. Comorbidities were significantly different and initially could not be adequately matched. Because of significant differences in baseline patient population characteristics after attempted matching between low- and high-volume centers, we used propensity adjustment with multivariate analysis. Using this alternative approach, no significant differences were observed between low- and high-volume centers for the presence of any complication, postoperative stroke, postoperative myocardial infarction, and readmission at 30 days.

CONCLUSION

In 1:1 nearest-neighbor matching with a high number of patients, our analysis did not result in well-matched cohorts for the effect of case volume on outcomes. Comparing analytical techniques for various outcomes highlights that outcome disparities may not be related to quality differences based on hospital size, but rather variability in patient populations between low- and high-volume institutions.

Weekend effect on 30-day mortality for ischemic and hemorrhagic stroke analyzed using severity index and staffing level

BACKGROUND AND PURPOSE

Previous studies on the weekend effect-a phenomenon where stroke outcomes differ depending on whether the stroke occurred on a weekend-mostly targeted ischemic stroke and showed inconsistent results. Thus, we investigated the weekend effect on 30-day mortality in patients with ischemic or hemorrhagic stroke considering the confounding effect of stroke severity and staffing level.

METHODS

We retrospectively analyzed data of patients hospitalized for ischemic or hemorrhagic stroke between January 1, 2015, and December 31, 2018, which were extracted from the claims database of the National Health Insurance System and the Medical Resource Report by the Health Insurance Review & Assessment Service. The primary outcome measure was 30-day all-cause mortality.

RESULTS

In total, 278,632 patients were included, among whom 84,240 and 194,392 had a hemorrhagic and ischemic stroke, respectively, with 25.8% and 25.1% of patients, respectively, being hospitalized during the weekend. Patients admitted on weekends had significantly higher 30-day mortality rates (hemorrhagic stroke 16.84%>15.55%, p<0.0001; ischemic stroke 5.06%>4.92%, p<0.0001). However, in the multi-level logistic regression analysis adjusted for case-mix, pre-hospital, and hospital level factors, the weekend effect remained consistent in patients with hemorrhagic stroke (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.00-1.10), while the association was no longer evident in patients with ischemic stroke (OR 1.01, 95% CI 0.96-1.06).

CONCLUSIONS

Weekend admission for hemorrhagic stroke was significantly associated with a higher mortality rate after adjusting for confounding factors. Further studies are required to understand factors contributing to mortality during weekend admission.

Editor's Choice - Distribution of Care and Hospital Incidence of Carotid Endarterectomy and Carotid Artery Stenting: A Secondary Analysis of German Hospital Episode Data

OBJECTIVE

This is a description of the German healthcare landscape regarding carotid artery disease, assessment of hospital incidence time courses for carotid endarterectomy (CEA) and carotid artery stenting (CAS), and simulation of potential effects of minimum hospital caseload requirements for CEA and CAS.

METHODS

The study is a secondary data analysis of diagnosis related group statistics data (2005-2016), provided by the German Federal Statistical Office. Cases encoded by German operation procedure codes for CEA or CAS and by International Classification of Diseases (ICD-10) codes for carotid artery disease were included. Hospitals were categorised into quartiles according to annual caseloads. Linear distances to the closest hospital fulfilling hypothetical caseload requirements were calculated.

RESULTS

A total of 132 411 and 33 709 patients treated with CEA and CAS from 2012 to 2016 were included. CEA patients had lower rates of myocardial infarction (1.4% vs. 1.8%) and death (1.2% vs. 4.0%), and CAS patients were more often treated after emergency admission (38.1% vs. 27.1%). Age standardised annual hospital incidences were 67.2 per 100 000 inhabitants for CEA and 16.3 per 100 000 inhabitants for CAS. The incidence for CEA declined from 2005 to 2016, with CAS rising again until 2016 after having declined from 2010 to 2013. Regarding distance from home to hospital, centres offering CEA are distributed more homogeneously across Germany, compared with those performing CAS. Hypothetical introduction of minimum annual caseloads (> 20 for CEA; > 10 for CAS) imply that 75% of the population would reach their hospital after travelling 45 km for CEA and 70 km for CAS.

CONCLUSION

Differences in spatial distribution mean that statutory minimum annual caseloads would have a greater impact on CAS accessibility than CEA in Germany. Presumably because of a decline in carotid artery disease and a transition towards individualised therapy for asymptomatic patients, hospital incidence for CEA has been declining.

Configuration of vascular services: a multiple methods research programme

Background

Vascular services is changing rapidly, having emerged as a new specialty with its own training and specialised techniques. This has resulted in the need for reconfiguration of services to provide adequate specialist provision and accessible and equitable services.

Objectives

To identify the effects of service configuration on practice, resource use and outcomes. To model potential changes in configuration. To identify and/or develop electronic data collection tools for collecting patient-reported outcome measures and other clinical information. To evaluate patient preferences for aspects of services other than health-related quality of life.

Design

This was a multiple methods study comprising multiple systematic literature reviews; the development of a new outcome measure for users of vascular services (the electronic Personal Assessment Questionnaire – Vascular) based on the reviews, qualitative studies and psychometric evaluation; a trade-off exercise to measure process utilities; Hospital Episode Statistics analysis; and the development of individual disease models and a metamodel of service configuration.

Setting

Specialist vascular inpatient services in England.

Data sources

Modelling and Hospital Episode Statistics analysis for all vascular inpatients in England from 2006 to 2018. Qualitative studies and electronic Personal Assessment Questionnaire – Vascular evaluation with vascular patients from the Sheffield area. The trade-off studies were based on a societal sample from across England.

Interventions

The data analysis, preference studies and modelling explored the effect of different potential arrangements for service provision on the resource use, workload and outcomes for all interventions in the three main areas of inpatient vascular treatment: peripheral arterial disease, abdominal aortic aneurysm and carotid artery disease. The electronic Personal Assessment Questionnaire – Vascular was evaluated as a potential tool for clinical data collection and outcome monitoring.

Main outcome measures

Systematic reviews assessed quality and psychometric properties of published outcome measures for vascular disease and the relationship between volume and outcome in vascular services. The electronic Personal Assessment Questionnaire – Vascular development considered face and construct validity, test–retest reliability and responsiveness. Models were validated using case studies from previous reconfigurations and comparisons with Hospital Episode Statistics data. Preference studies resulted in estimates of process utilities for aneurysm treatment and for travelling distances to access services.

Results

Systematic reviews provided evidence of an association between increasing volume of activity and improved outcomes for peripheral arterial disease, abdominal aortic aneurysm and carotid artery disease. Reviews of existing patient-reported outcome measures did not identify suitable condition-specific tools for incorporation in the electronic Personal Assessment Questionnaire – Vascular. Reviews of qualitative evidence, primary qualitative studies and a Delphi exercise identified the issues to be incorporated into the electronic Personal Assessment Questionnaire – Vascular, resulting in a questionnaire with one generic and three disease-specific domains. After initial item reduction, the final version has 55 items in eight scales and has acceptable psychometric properties. The preference studies showed strong preference for endovascular abdominal aortic aneurysm treatment (willingness to trade up to 0.135 quality-adjusted life-years) and for local services (up to 0.631 quality-adjusted life-years). A simulation model with a web-based interface was developed, incorporating disease-specific models for abdominal aortic aneurysm, peripheral arterial disease and carotid artery disease. This predicts the effects of specified reconfigurations on workload, resource use, outcomes and cost-effectiveness. Initial exploration suggested that further reconfiguration of services in England to accomplish high-volume centres would result in improved outcomes, within the bounds of cost-effectiveness usually considered acceptable in the NHS.

Limitations

The major source of evidence to populate the models was Hospital Episode Statistics data, which have limitations owing to the complexity of the data, deficiencies in the coding systems and variations in coding practice. The studies were not able to address all of the potential barriers to change where vascular services are not compliant with current NHS recommendations.

Conclusions

There is evidence of potential for improvement in the clinical effectiveness and cost-effectiveness of vascular services through further centralisation of sites where major vascular procedures are undertaken. Preferences for local services are strong, and this may be addressed through more integrated services, with a range of services being provided more locally. The use of a web-based tool for the collection of clinical data and patient-reported outcome measures is feasible and can provide outcome data for clinical use and service evaluation.

Future work

Further evaluation of the economic models in real-world situations where local vascular service reconfiguration is under consideration and of the barriers to change where vascular services do not meet NHS recommendations for service configuration is needed. Further work on the electronic Personal Assessment Questionnaire – Vascular is required to assess its acceptability and usefulness in clinical practice and to develop appropriate report formats for clinical use and service evaluation. Further studies to assess the implications of including non-health-related preferences for care processes, and location of services, in calculations of cost-effectiveness are required.

Study registration

This study is registered as PROSPERO CRD42016042570, CRD42016042573, CRD42016042574, CRD42016042576, CRD42016042575, CRD42014014850, CRD42015023877 and CRD42015024820.

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 9, No. 5. See the NIHR Journals Library website for further project information.

Variation in Pediatric Asthmonia Diagnosis and Outcomes among Hospitalized Children

RATIONALE

Although <5% of children hospitalized with an asthma exacerbation have pneumonia that can be radiographically confirmed, at some hospitals asthma-pneumonia co-diagnosis is so common that the term "asthmonia" is used to describe the phenomenon. High rates of asthmonia diagnosis may incur unwarranted healthcare costs and contribute to unnecessary antibiotic prescribing.

OBJECTIVE

To characterize hospital variation in rates of pediatric asthmonia diagnosis and analyze associations between hospitals' asthmonia diagnosis rates and clinical outcomes.

METHODS

We conducted a cross-sectional analysis of 274 hospitals contributing to the Premier Healthcare Database. Children and adolescents 2-17 years of age were included if they were hospitalized with an asthma exacerbation from 10/1/2015-6/30/2018. Asthmonia was defined as a discharge diagnosis of pneumonia in a patient with an asthma exacerbation. To compute hospital-level risk-standardized asthmonia rates, hierarchical generalized linear models with hospital random effects were estimated, adjusting for patient characteristics. The median odds ratio (MOR) was calculated to quantify the effect of hospital-level clustering on asthmonia diagnosis. Hospitals were stratified into quartiles based on risk-standardized asthmonia diagnosis rates to identify associated hospital characteristics. Generalized linear models, adjusting for hospital characteristics, were developed to compute associations between hospital risk-standardized rates and clinical outcomes.

RESULTS

Of 24606 asthma exacerbations, 19402 (78.9%) were diagnosed with asthma alone and 5204 (21.1%) received asthma-pneumonia co-diagnoses. The hospital median risk-adjusted asthmonia diagnosis rate was 20.9% (IQR:16.2-27.2%, range:8.4-55.9%). The MOR was 1.75 (95% CI:1.63-1.86). Compared to hospitals in the lowest quartile of asthma-pneumonia co-diagnosis, those in the highest quartile were more likely to be smaller, non-teaching, rural hospitals with minimal subspecialty support (all p<0.001). Hospitals with high rates of risk-standardized asthmonia diagnosis had greater antibiotic utilization, more prolonged lengths of stay, and higher costs, with no significant differences in risk of transfer or readmission.

CONCLUSIONS

Marked variation exists in rates of asthmonia diagnosis, and the hospital of admission is one of the strongest predictors of diagnosis. Efforts to reduce rates of unwarranted asthmonia diagnosis are needed, particularly at small, rural, non-teaching hospitals with minimal pediatric specialty support.

The Relationship Between Carotid Revascularization Procedural Volume and Perioperative Outcomes in Australia and New Zealand

Carotid endarterectomy (CEA) and carotid artery stenting (CAS) prevent stroke in selected patients. However, each intervention carries a risk of perioperative complications including stroke or death (S/D). We aimed to determine the relationship between operator volume, hospital volume, and the perioperative risk of S/D in carotid revascularization in Australia and New Zealand. Retrospective analysis was performed on prospectively collected data extracted from the Australasian Vascular Audit between 2010 and 2017. Annual caseload volume was analyzed in quintiles (Q) using multivariate regression to assess its impact on perioperative S/D. Carotid endarterectomy procedures (n = 16 765) demonstrated higher S/D rates for lower-volume operators (2.21% for Q1-Q3 [1-17 annual cases] vs 1.76% for Q4-Q5 [18-61 annual cases]; odds ratio [OR]: 1.28; 95% CI: 1.001-1.64; P = .049). Carotid artery stenting procedures (n = 1350) also demonstrated higher S/D rates for lower-volume operators (2.63% for Q1-Q3 [1-11 annual cases] vs 0.37% for Q4-Q5 [12-31 annual cases]; OR: 6.11; 95% CI: 1.27-29.33; P = .024). No significant hospital volume-outcome effect was observed for either procedure. An inverse relationship was demonstrated between operator volume and perioperative S/D rates following CEA and CAS. Consideration of minimum operator thresholds, restructuring of services and networked referral pathways of care in Australia and New Zealand, would likely result in improved patient outcomes.

Improving Quality of Carotid Interventions: Identifying Hospital-Level Structural Factors that can Improve Outcomes

BACKGROUND

"Structural factors" relating to organization of hospitals may affect procedural outcomes. This study's aim was to clarify associations between structural factors and outcomes after carotid endarterectomy (CEA) and carotid endarterectomy stenting (CAS).

METHODS

A systematic review of studies published in English since 2005 was conducted. Structural factors assessed were as follows: population size served by the vascular department; number of hospital beds; availability of dedicated vascular beds; established clinical pathways; surgical intensive care unit (SICU) size; and specialty of surgeon/interventionalist. Primary outcomes were as follows: mortality; stroke; cardiac complications; length of hospital stay (LOS); and cost.

RESULTS

There were 11 studies (n = 95,100 patients) included in this systematic review. For CEA, reduced mortality (P < 0.0001) and stroke rates (P = 0.001) were associated with vascular departments serving >75,000 people. Larger hospitals were associated with lower mortality, stroke rate, and cardiac events, compared with smaller hospitals (less than 130 beds). Provision of vascular beds after CEA was associated with lower mortality (P = 0.0008) and fewer cardiac events (P = 0.03). Adherence to established clinical pathways was associated with reduced stroke and cardiac event rates while reducing CEA costs. Large SICUs (≥7 beds) and dedicated intensivists were associated with decreased mortality after CEA while a large SICU was associated with reduced stroke rate (P = 0.001). Vascular surgeons performing CEA were associated with lower stroke rates and shorter LOS (P = 0.0001) than other specialists. CAS outcomes were not influenced by specialty but costless when performed by vascular surgeons (P < 0.0001).

CONCLUSIONS

Structural factors affect CEA outcomes, but data on CAS were limited. These findings may inform reconfiguration of vascular services, reducing risks and costs associated with carotid interventions.

Do small hospitals have lower quality? Evidence from the English NHS

We investigate the extent to which small hospitals are associated with lower quality. We first take a patient perspective, and test if, controlling for casemix, patients admitted to small hospitals receive lower quality than those admitted to larger hospitals. We then investigate if differences in quality between large and small hospitals can be explained by hospital characteristics such as hospital type and staffing. We use a range of quality measures including hospital mortality rates (overall and for specific conditions), hospital acquired infection rates, waiting times for emergency patients, and patient perceptions of the care they receive. We find that small hospitals, with fewer than 400 beds, are generally not associated with lower quality before or after controlling for hospital characteristics. The only exception is heart attack mortality, which is generally higher in small hospitals.

Association of Operator and Hospital Experience With Procedural Success Rates and Outcomes in Patients Undergoing Percutaneous Coronary Interventions for Chronic Total Occlusions

Background:

An inverse relationship has been described between procedural success and outcomes of all major cardiovascular procedures. However, this relationship has not been studied for percutaneous coronary intervention (PCI) of chronic total occlusion (CTO).

Methods:

We analyzed the data on patients enrolled in Blue Cross Blue Shield of Michigan Cardiovascular Consortium registry in Michigan (January 1, 2010 to March 31, 2018) to evaluate the association of operator and hospital experience with procedural success and outcomes of patients undergoing CTO-PCI. CTO-PCI was defined as intervention of a 100% occluded coronary artery presumed to be ≥3 months old.

Results:

Among 210 172 patients enrolled in the registry, 7389 (3.5%) CTO-PCIs were attempted with a success rate of 53%. CTO-PCI success increased with operator experience (45% and 65% in the lowest and highest experience tertiles) and was the highest for highly experienced operators at higher experience centers and the lowest for inexperienced operators at low experience hospitals. Multivariable logistic regression models (with spline transformed prior operator and institutional experience) demonstrated a positive relationship between prior operator and site experience and procedural success rates (likelihood ratio test=141.12, df=15, P <0.001) but no relationship between operator and site experience and major adverse cardiac event (likelihood ratio test=19.12, df=15, P =0.208).

Conclusions:

Operator and hospital CTO-PCI experiences were directly related to procedural success but were not related to major adverse cardiac event among patients undergoing CTO-PCIs. Inexperienced operators at high experience centers had significantly higher success but not major adverse cardiac event rates compared with inexperienced operators at low experience centers. These data suggested that CTO-PCI safety and success could potentially be improved by selective referral of these procedures to experienced operators working at highly experienced centers.

Regionalization of esophagectomy: where are we now?

The morbidity and mortality benefits of performing high-risk operations in high-volume centers by high-volume surgeons are evident. Regionalization is a proposed strategy to leverage high-volume centers for esophagectomy to improve quality outcomes. Internationally, regionalization occurs under national mandates. Those mandates do not exist in the United States and spontaneous regionalization of esophagectomy has only modestly occurred in the U.S. Regionalization must strike a careful balance and not limit access to optimal oncologic care to our most vulnerable cancer patient populations in rural and disadvantaged socioeconomic areas. We reviewed the recent literature highlighting: the justification of hospital and surgeon annual esophagectomy volumes for regionalization; how safety performance metrics could influence regionalization; whether regionalization is occurring in the US; what impact regionalization may have on esophagectomy costs; and barriers to patients traveling to receive oncologic treatment at regionalized centers of excellence.

Asymptomatic Carotid Stenosis: Intervention or Best Medical Therapy?

PURPOSE OF REVIEW

Provide a current overview regarding the optimal strategy for managing patients with asymptomatic carotid artery stenosis.

RECENT FINDINGS

Carotid endarterectomy (CEA) and carotid artery stenting (CAS) reduce long-term stroke risk in asymptomatic patients. However, CAS is associated with a higher risk of peri-procedural stroke. Improvements in best medical therapy (BMT) have renewed uncertainty regarding the extent to which results from older randomised controlled trials (RCTs) comparing outcomes following carotid intervention can be generalised to modern medical practise. 'Average surgical risk' patients with an asymptomatic carotid artery stenosis of 60-99% and increased risk of late stroke should be considered for either CEA or CAS. In patients deemed 'high risk' for surgery, CAS is indicated. Use of an anti-platelet, anti-hypertensive and statin, with strict glycaemic control, is recommended. Results from ongoing large, multicentre RCTs comparing CEA, CAS and BMT will provide clarity regarding the optimal management of patients with asymptomatic carotid artery stenosis.