Statistical modeling of the volume-outcome effect for carotid endarterectomy for 10 years of a statewide database

Higher stroke risk after carotid endarterectomy and transcarotid artery revascularization is associated with relative surgeon volume ratio

OBJECTIVE

Adoption of transcarotid artery revascularization (TCAR) by surgeons has been variable, with some still performing traditional carotid endarterectomy (CEA), whereas others have shifted to mostly TCAR. Our goal was to evaluate the association of relative surgeon volume of CEA to TCAR with perioperative outcomes.

METHODS

The Vascular Quality Initiative CEA and carotid artery stent registries were analyzed from 2021 to 2023 for symptomatic and asymptomatic interventions. Surgeons participating in both registries were categorized in the following CEA to CEA+TCAR volume percentage ratios: 0.25 (majority TCAR), 0.26 to 0.50 (more TCAR), 0.51 to 0.75 (more CEA), and 0.76 to 1.00 (majority CEA). Primary outcomes were rates of perioperative ipsilateral stroke, death, cranial nerve injury, and return to the operating room for bleeding.

RESULTS

There were 50,189 patients who underwent primary carotid revascularization (64.3% CEA and 35.7% TCAR). CEA patients were younger (71.1 vs 73.5 years, P < .001), with more symptomatic cases, less coronary artery disease, diabetes, and lower antiplatelet and statin use (all P < .001). TCAR patients had lower rates of smoking, obesity, and dialysis or renal transplant (all P < .001). Postoperative stroke after CEA was significantly impacted by the operator CEA to TCAR volume ratio (P = .04), with surgeons who perform majority TCAR and more TCAR having higher postoperative ipsilateral stroke (majority TCAR odds ratio [OR]: 2.15, 95% confidence interval [CI]: 1.16-3.96, P = .01; more TCAR OR: 1.42, 95% CI: 1.02-1.96, P = .04), as compared with those who perform majority CEA. Similarly, postoperative stroke after TCAR was significantly impacted by the CEA to TCAR volume ratio (P = .02), with surgeons who perform majority CEA and more CEA having higher stroke (majority CEA OR: 1.51, 95% CI: 1.00-2.27, P = .05; more CEA OR: 1.50, 95% CI: 1.14-2.00, P = .004), as compared with those who perform majority TCAR. There was no association between surgeon ratio and perioperative death, cranial nerve injury, and return to the operating room for bleeding for either procedure.

CONCLUSIONS

The relative surgeon CEA to TCAR ratio is significantly associated with perioperative stroke rate. Surgeons who perform a majority of one procedure have a higher stroke rate in the other. Surgeons offering both operations should maintain a balanced practice and have a low threshold to collaborate as needed.

The effect of institutional case volume on post-operative outcomes after endarterectomy and stenting for symptomatic carotid stenosis

OBJECTIVE

To investigate the effects of yearly institutional case volume for carotid endarterectomy (CEA) and stenting (CAS) among symptomatic carotid stenosis patients on the rates of postoperative stroke and inpatient mortality.

MATERIALS AND METHODS

Patients with prior stroke ("symptomatic") undergoing CEA or CAS during an inpatient stay were identified from the National Inpatient Sample for years 2012-2015. The primary variable was volume of CEA or CAS performed annually by each institution. The primary outcome was a composite variable for in-hospital death or postoperative stroke.

RESULTS

A total of 5,628 patients with symptomatic carotid stenosis underwent CEA, while 245 underwent CAS. In the symptomatic CEA population, 519 (9.2 %) patients experienced postoperative stroke or mortality, and were more likely to be treated at centers with a lower yearly institutional volume (median 10 [IQR 5-15] versus 10 [7-20] cases, p < 0.001). In the symptomatic CAS population, 32 (13.1 %) patients experienced stroke or mortality, and these patients were also more likely to undergo treatment at hospitals with a lower yearly institutional volume (median 5 [IQR 5-7] versus 5 [5-10] cases, p = 0.044). Thresholds for yearly institutional volume found differences in adverse outcome between 0-9, 10-29, and ≥30 cases/year (11.7 % vs 8.4 % vs 6.0 %, p < 0.001) for CEA, and differences in postoperative stroke between 0-9 and ≥10 cases/year for CAS (11.0 % vs 1.4 %, p = 0.028).

CONCLUSIONS

Hospitals performing higher volumes of CEA or CAS have fewer postoperative strokes. The threshold reported herein is ≥30 CEA procedures or ≥10 CAS procedures annually for appreciably improved outcomes.

Guideline Compliant Minimum Asymptomatic Carotid Endarterectomy Surgeon and Hospital Volume Cutoffs

BACKGROUND

There is a known association between volume and outcomes after carotid endarterectomy (CEA). A recent analysis suggested rates of stroke and death do not significantly reduce after a surgeon volume cutoff of 20 CEAs per year. However, these results would severely limit access. The objective here is to identify a lower optimal cutpoint for surgeon and hospital volume for asymptomatic CEA.

METHODS

We evaluated asymptomatic CEA patients using The New York Statewide Planning and Research Cooperative System database from 2000-2014. The relationship of 3-year averaged volumes for surgeons and hospitals to 30-day stroke was assessed using multiple logistic regression and included both hospital and surgeon volume in all analyses. Optimized cut points were the lowest significant volume cutoff that minimized the adjusted odds ratio of stroke.

RESULTS

We studied 32,549 CEAs performed by 271 surgeons in 136 centers by vascular surgeons. The median surgeon volume was 26.3 (interquartile range: 12.3-51.7) and the median hospital volume was 67 (interquartile range: 36.3-119.3). The surgeon volume cut point was 3 and the hospital volume cut point was 6 cases per year. There were 756 (2.3%) procedures performed by surgeons with a volume < 3 and 560 (1.7%) procedures performed by hospitals with a volume < 6. Perioperative stroke and death rates were 2.0% (95% confidence interval [CI]: 1.8-2.1) and 3.8% (95% CI: 2.6-5.5) for an average yearly surgeon volume ≥ 3 and < 3 (P = 0.070), respectively. The combined stroke and death rate was 2.0% (95% CI: 1.8-2.1) and 4.8% (95% CI: 3.2-7.0) for an average yearly center volume ≥ 6 and < 6 (P = 0.007), respectively. A combined surgeon and hospital volume variable also predicted outcomes and low-volume procedures did not meet previously proposed American Heart Association and Society for Vascular Surgery quality measures.

CONCLUSIONS

These data demonstrate an improvement in outcomes at a lower volume threshold than previously reported. These modest cutoff values should be used for asymptomatic CEA volume guideline formation and for future studies, after accounting for the impact of other important factors that may be driving volume-outcome relationships in asymptomatic CEA.

Association between Hospital Carotid Endarterectomy Procedure Volumes and In-Hospital Mortality in São Paulo State

Background

Previous studies indicate an inverse relationship between hospital volume and mortality after carotid endarterectomy. However, data at the level of Brazil are lacking.

Objectives

To assess the relationship between hospital carotid endarterectomy procedure volumes and mortality in the state of São Paulo.

Methods

Data from the São Paulo State Hospital Information System on all carotid endarterectomies performed between 2015 and 2019 were analyzed. Hospitals were categorized into clusters by annual volume of surgeries (1-10, 11-25, and ≥26). Multiple logistic regression models were used to determine whether the volume of carotid endarterectomy procedures was an independent predictor of in-hospital mortality among patients undergoing this procedure.

Results

Crude in-hospital mortality was nearly 60 percent lower in patients who underwent carotid endarterectomy at the highest volume hospitals than among those who underwent endarterectomy at the lowest volume hospitals (unadjusted OR of survival to hospital discharge, 2.41; 95% CI, 1.11-5.23; p = 0.027). Although this lower rate represents 1.5 fewer deaths per 100 patients treated, high-volume centers are more likely than low-volume centers to perform elective procedures, thus the analysis did not retain statistical significance when adjusted for admission character (OR, 1.69; 95% CI, 0.74-3.87; p = 0.215).

Conclusions

In a contemporary Brazilian registry, higher volume carotid endarterectomy centers were associated with lower in-hospital mortality than lower volume centers. Further studies are needed to verify this relationship considering the presence of symptoms in patients.

Long-term outcomes of symptomatic and asymptomatic patients undergoing carotid endarterectomy in an average-volume community hospital

BACKGROUND

Long-term benefit of carotid endarectomy has not yet been fully investigated in average volume centers. Thus our purpose is to evaluate long-term results of carotid endarterectomies at a medium-volume hospital.

METHODS

A retrospective analysis of carotid artery stenosis operated between 2008 and 2017 in a community hospital was done. Demographic and postoperative outcomes were evaluated in short and long-term by Kaplan-Meier survival analysis.

RESULTS

167 procedures in 159 patients were included. Average age was 72 years, and 65% were men. Twenty-nine percent of the patients were symptomatic and the rest asymptomatic. Median hospitalization was 3 (IQR 3-4) days and the mean follow-up was 56 months. No hospital mortality was recorded. At 120-month follow-up, freedom of stroke was 97.4%, death 97.3%, restenosis, 98.7% and all combined events 92.9% (log rank p = .042) Combined event-free survival was 84.4% in symptomatic patients, and 96.1% in asymptomatic patients (log rank p = .025).

CONCLUSIONS

In a medium-volume hospital combined event-free survival was 84.4% in symptomatic patients and 96.1% in asymptomatic at a 10-year follow-up.

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.

The Surgeon Volume-outcome Relationship: Not Yet Ready for Policy

OBJECTIVE

Increasing surgeon volume may improve outcomes for index operations. We hypothesized that there may be surrogate operative experiences that yield similar outcomes for surgeons with a low-volume experience with a specific index operation, such as esophagectomy.

BACKGROUND

The relationship between surgeon volume and outcomes has potential implications for credentialing of surgeons. Restrictions of privileges based on surgeon volume are only reasonable if there is no substitute for direct experience with the index operation. This study was aimed at determining whether there are valid surrogates for direct experience with a sample index operation-open esophagectomy.

METHODS

The Nationwide Inpatient Sample (2003-2009) was utilized. Surgeons were stratified into low and high-volume groups based on annual volume of esophagectomy. Surrogate volume was defined as the aggregate annual volume per surgeon of upper gastrointestinal operations including excision of esophageal diverticulum, gastrectomy, gastroduodenectomy, and repair of diaphragmatic hernia.

RESULTS

In all, 26,795 esophagectomies were performed nationwide (2003-2009), with a crude inhospital mortality rate of 5.2%. Inhospital mortality decreased with increasing volume of esophagectomies performed annually: 7.7% and 3.8% for low and high-volume surgeons, respectively (P < 0.0001). Among surgeons with a low-volume esophagectomy experience, increasing volume of surrogate operations improved the outcomes observed for esophagectomy: 9.7%, 7.1%, and 4.3% for low, medium, and high-surrogate-volume surgeons, respectively (P = 0.016).

CONCLUSIONS

Both operation-specific volume and surrogate volume are significant predictors of inhospital mortality for esophagectomy. Based on these observations, it would be premature to limit hospital privileges based solely on operation-specific surgeon volume criteria.

Relationship between patient safety indicator events and comprehensive stroke center volume status in the treatment of unruptured cerebral aneurysms

OBJECTIVE

The Agency of Healthcare Research and Quality (AHRQ) has defined Patient Safety Indicators (PSIs) for assessments in quality of inpatient care. The hypothesis of this study is that, in the treatment of unruptured cerebral aneurysms (UCAs), PSI events are less likely to occur in hospitals meeting the volume thresholds defined by The Joint Commission for Comprehensive Stroke Center (CSC) certification.

METHODS

Using the 2002–2011 National (Nationwide) Inpatient Sample, patients treated electively for a nonruptured cerebral aneurysm were selected. Patients were evaluated for PSI events (e.g., pressure ulcers, retained surgical item, perioperative hemorrhage, pulmonary embolism, sepsis) defined by AHRQ-specified ICD-9 codes. Hospitals were categorized by treatment volume into CSC or non-CSC volume status based on The Joint Commission’s annual volume thresholds of at least 20 patients with subarachnoid hemorrhage and performance of 15 or more endovascular coiling or surgical clipping procedures for aneurysms.

RESULTS

A total of 65,824 patients underwent treatment for an unruptured cerebral aneurysm. There were 4818 patients (7.3%) in whom at least 1 PSI event occurred. The overall inpatient mortality rate was 0.7%. In patients with a PSI event, this rate increased to 7% compared with 0.2% in patients without a PSI event (p < 0.0001). The overall rate of poor outcome was 3.8%. In patients with a PSI event, this rate increased to 23.3% compared with 2.3% in patients without a PSI event (p < 0.0001). There were significant differences in PSI event, poor outcome, and mortality rates between non-CSC and CSC volume-status hospitals (PSI event, 8.4% vs 7.2%; poor outcome, 5.1% vs 3.6%; and mortality, 1% vs 0.6%). In multivariate analysis, all patients treated at a non-CSC volume-status hospital were more likely to suffer a PSI event with an OR of 1.2 (1.1–1.3). In patients who underwent surgery, this relationship was more substantial, with an OR of 1.4 (1.2–1.6). The relationship was not significant in the endovascularly treated patients.

CONCLUSIONS

In the treatment of unruptured cerebral aneurysms, PSI events occur relatively frequently and are associated with significant increases in morbidity and mortality. In patients treated at institutions achieving the volume thresholds for CSC certification, the likelihood of having a PSI event, and therefore the likelihood of poor outcome and mortality, was significantly decreased. These improvements are being driven by the improved outcomes in surgical patients, whereas outcomes and mortality in patients treated endovascularly were not sensitive to the CSC volume status of the hospital and showed no significant relationship with treatment volumes.

Effect of Surgeon and Hospital Volume on Morbidity and Mortality After Hip Fracture

BACKGROUND

Prior studies have examined the relationship between surgeon and hospital volumes and outcome following hip fracture surgical procedures, but the results have been inconclusive. The purpose of this study was to assess the hip fracture volume-outcome relationship by analyzing data from a large, managed care registry.

METHODS

The Kaiser Permanente Hip Fracture Registry prospectively records information on surgically treated hip fractures within the managed health-care system. Using this registry, all surgically treated hip fractures in patients 60 years of age or older were identified. Surgeon and hospital volume were defined as the number of hip fracture surgical procedures performed in the preceding 12 months and were divided into tertiles (low, medium, and high). The primary outcome was mortality at 1 year postoperatively. Secondary outcomes were mortality at 30 and 90 days postoperatively as well as reoperation (lifetime), medical complications (90-day), and unplanned readmission (30-day). To determine the relationship between volume and these outcome measures, multivariate logistic and Cox proportional hazards regression were performed, controlling for potentially confounding variables.

RESULTS

Of 14,294 patients in the study sample, the majority were female (71%) and white (79%), and the mean age was 81 years. The overall mortality rate was 6% at 30 days, 11% at 90 days, and 21% at 1 year. We did not find an association between surgeon or hospital volume and mortality at 30 days, 90 days, or 1 year (p > 0.05). There was also no association between surgeon or hospital volume and reoperation, medical complications, or unplanned readmission (p > 0.05).

CONCLUSIONS

In this analysis of hip fractures treated in a large integrated health-care system, the observed rates of mortality, reoperation, medical complications, and unplanned readmission did not differ by surgeon or hospital volume. In contrast to other orthopaedic procedures, such as total joint arthroplasty, our data do not suggest that hip fractures need to be preferentially directed toward high-volume surgeons or hospitals for treatment.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Evaluation and Management of Atherosclerotic Carotid Stenosis

Medical therapies for the prevention of stroke have advanced considerably in the past several years. There can also be a role for mechanical restoration of the lumen by endarterectomy or stenting in selected patients with high-grade atherosclerotic stenosis of the extracranial carotid artery. Endarterectomy is generally recommended for patients with high-grade symptomatic carotid stenosis. Stenting is considered an option for patients at high risk of complications with endarterectomy. Whether revascularization is better than contemporary medical therapy for asymptomatic extracranial carotid stenosis is a subject of several ongoing randomized clinical trials in the United States and internationally.

Significant Association of Annual Hospital Volume With the Risk of Inhospital Stroke or Death Following Carotid Endarterectomy but Likely Not After Carotid Stenting

Background—

Associations between hospital volume and the risk of stroke or death following carotid endarterectomy (CEA) and carotid artery stenting (CAS) on a national level in Germany were analyzed.

Methods and Results—

Secondary data analysis using microdata from the nationwide statutory German quality assurance database on all surgical or endovascular carotid interventions on the extracranial carotid artery between 2009 and 2014. Hospitals were categorized into empirically determined quintiles according to the annual case volume. The resulting volume thresholds were 10, 25, 46, and 79 for CEA and 2, 6, 12, and 26 for CAS procedures. The primary outcome was any stroke or death before hospital discharge. For risk-adjusted analyses, a multilevel regression model was applied. The analysis included 161 448 CEA and 17 575 CAS procedures. In CEA patients, the crude risk of stroke or death decreased monotonically from 4.2% (95% confidence interval, 3.6%–4.9%) in low-volume hospitals (first quintile 1–10 CEA per year) to 2.1% (2.0%–2.2%) in hospitals providing ≥80 CEA per year (fifth quintile; P <0.001 for trend). The overall risk of any stroke or death in CAS patients was 3.7% (3.5%–4.0%), but no trend on annual volume was seen ( P =0.304). Risk-adjusted analyses confirmed a significant inverse relationship between hospital volume (categorized or continuous) and the risk of stroke or death after CEA but not CAS procedures.

Conclusions—

An inverse volume–outcome relationship in CEA-treated patients was demonstrated. No significant association between hospital volume and the risk of stroke or death was found for CAS.

Carotid Endarterectomy versus Carotid Artery Stenting: No Difference in 30-Day Postprocedure Readmission Rates

BACKGROUND

In the United States, ischemic stroke is a major cause of morbidity and mortality, precipitated by carotid artery stenosis in 1 of every 5 individuals who suffer a stroke. Carotid endarterectomy (CEA) and carotid artery stenting (CAS) are 2 proven means of intervening on this disease process, with similar patient outcomes. Little is known about the burden of readmission after each of these procedures. We hypothesized that no difference in readmission rates within 30 days would exist for these 2 procedures, in spite of baseline differences that might exist between the 2 patient populations.

METHODS

Using the Pennsylvania Health Care Cost Containment Council database, we identified 4,319 people who underwent CEA (n = 3,640) or CAS (n = 679) in Pennsylvania in 2011. Univariate analyses were performed to compare patient characteristics and outcomes, including reasons for readmission, between patients who underwent CEA and those who underwent CAS. Logistic regression was used to estimate the effect of intervention on 30-day readmission, after controlling for potential confounders. Time to readmission was analyzed using the Kaplan-Meier method.

RESULTS

Patients who underwent CEA and CAS differed in a few notable ways, including age, race, admission type, and comorbid conditions such as congestive heart failure, hemiplegia and paraplegia, and renal disease. The unadjusted rate of 30-day readmission was 9.37% for CEA and 10.75% for CAS (P = 0.26). After controlling for patient and procedure characteristics, differences between 30-day readmission rates were still not statistically significant (odds ratio = 1.13; P = 0.39). Finally, time to readmission was similar for those who underwent CEA and those who underwent CAS (P = 0.19). Complications associated with surgery comprised less than 10% of primary readmission diagnoses for both groups.

CONCLUSIONS

Readmission rates after CEA and CAS for carotid artery stenosis are approximately 10%. In spite of differences between patients with carotid stenosis who are selected for endarterectomy and stenting, the choice of procedure does not appear to be associated with different readmission rates or time to readmission, even after controlling for patient characteristics.

Surgeon case volume and 30-day mortality after carotid endarterectomy among contemporary medicare beneficiaries: before and after national coverage determination for carotid artery stenting

BACKGROUND AND PURPOSE

After the 2005 National Coverage Determination to reimburse carotid artery stenting (CAS) for Medicare beneficiaries, the number of CAS procedures increased and carotid endarterectomy (CEA) decreased. We evaluated trends in surgeons' past-year CEA case-volume and 30-day mortality after CEA, and their association before and after the National Coverage Determination.

METHODS

In a retrospective cohort study of patients undergoing CEA (2001-2008) and CAS (2005-2008) using Medicare data, we described yearly trends of CEA and CAS rates, patient characteristics, and 30-day mortality after CEA. We used logistic regression adjusting for patient- and surgeon-level factors to assess the effect of surgeon case volume on 30-day mortality after CEA.

RESULTS

We identified 454 717 CEA and 27 943 CAS patients. Patients undergoing CEA in recent years were older and had more comorbidities than earlier years. CEA rates per 10 000 beneficiaries declined from 18.1 in 2002 to 12.7 in 2008, whereas median surgeon past-year case-volume declined from 27 to 21. The CAS rates peaked at 2.3 per 10 000 beneficiaries in 2006 but declined to 1.8 in 2008, resulting in declining overall revascularization procedure rates during 2005 to 2008. Thirty day post-CEA mortality was 1.40% (95% confidence interval, 1.34-1.47) in 2001 to 2002 and 1.17% (1.10-1.24) in 2007 to 2008. Surgeon's past-year case-volume of <10 was associated with higher 30-day mortality consistently during 2001 to 2008.

CONCLUSIONS

The rate of CEA procedures decreased substantially during 2001 to 2008, as did surgeon past-year case-volume. The postprocedural mortality in Medicare beneficiaries was high compared with trial patients but somewhat improved over time. Those operated by lower past-year case-volume surgeons had increased mortality.

Unchanged safety outcomes in deep brain stimulation surgery for Parkinson disease despite a decentralization of care

OBJECT

Early work on deep brain stimulation (DBS) surgery, when procedures were mostly carried out in a small number of high-volume centers, demonstrated a relationship between surgical volume and procedural safety. However, over the past decade, DBS has become more widely available in the community rather than solely at academic medical centers. The authors examined the Nationwide Inpatient Sample (NIS) to study the safety of DBS surgery for Parkinson disease (PD) in association with this change in practice patterns.

METHODS

The NIS is a stratified sample of 20% of all patient discharges from nonfederal hospitals in the United States. The authors identified patients with a primary diagnosis of PD (332.0) and a primary procedure code for implantation/replacement of intracranial neurostimulator leads (02.93) who underwent surgery between 2002 and 2009. They analyzed outcomes using univariate and hierarchical, logistic regression analyses.

RESULTS

The total number of DBS cases remained stable from 2002 through 2009. Despite older and sicker patients undergoing DBS, procedural safety (rates of non-home discharges, complications) remained stable. Patients at low-volume hospitals were virtually indistinguishable from those at high-volume hospitals, except that patients at low-volume hospitals had slightly higher comorbidity scores (0.90 vs 0.75, p < 0.01). Complications, non-home discharges, length of hospital stay, and mortality rates did not significantly differ between low- and high-volume hospitals when accounting for hospital-related variables (caseload, teaching status, location).

CONCLUSIONS

Prior investigations have demonstrated a robust volume-outcome relationship for a variety of surgical procedures. However, the present study supports safety of DBS at smaller-volume centers. Prospective studies are required to determine whether low-volume centers and higher-volume centers have similar DBS efficacy, a critical factor in determining whether DBS is comparable between centers.

Online doctor reviews: do they track surgeon volume, a proxy for quality of care?

Background

Increasingly, consumers are accessing the Internet seeking health information. Consumers are also using online doctor review websites to help select their physician. Such websites tally numerical ratings and comments from past patients. To our knowledge, no study has previously analyzed whether doctors with positive online reputations on doctor review websites actually deliver higher quality of care typically associated with better clinical outcomes and better safety records.

Objective

For a number of procedures, surgeons who perform more procedures have better clinical outcomes and safety records than those who perform fewer procedures. Our objective was to determine if surgeon volume, as a proxy for clinical outcomes and patient safety, correlates with online reputation.

Methods

We investigated the numerical ratings and comments on 9 online review websites for high- and low-volume surgeons for three procedures: lumbar surgery, total knee replacement, and bariatric surgery. High-volume surgeons were randomly selected from the group within the highest quartile of claims submitted for reimbursement using the procedures’ relevant current procedural terminology (CPT) codes. Low-volume surgeons were randomly selected from the lowest quartile of submitted claims for the procedures’ relevant CPT codes. Claims were collated within the Normative Health Information Database, covering multiple payers for more than 25 million insured patients.

Results

Numerical ratings were found for the majority of physicians in our sample (547/600, 91.2%) and comments were found for 385/600 (64.2%) of the physicians. We found that high-volume (HV) surgeons could be differentiated from low-volume (LV) surgeons independently by analyzing: (1) the total number of numerical ratings per website (HV: mean = 5.85; LV: mean = 4.87, P<.001); (2) the total number of text comments per website (HV: mean = 2.74; LV: mean = 2.30, P=.05); (3) the proportion of glowing praise/total comments about quality of care (HV: mean = 0.64; LV: mean = 0.51, P=.002); and (4) the proportion of scathing criticism/total comments about quality of care (HV: mean = 0.14; LV: mean = 0.23, P= .005). Even when these features were combined, the effect size, although significant, was still weak. The results revealed that one could accurately identify a physician’s patient volume via discriminant and classification analysis 61.6% of the time. We also found that high-volume surgeons could not be differentiated from low-volume surgeons by analyzing (1) standardized z score numerical ratings (HV: mean = 0.07; LV: mean = 0, P=.27); (2) proportion of glowing praise/total comments about customer service (HV: mean = 0.24; LV: mean = 0.22, P=.52); and (3) proportion of scathing criticism/total comments about customer service (HV: mean = 0.19; LV: mean = 0.21, P=.48).

Conclusions

Online review websites provide a rich source of data that may be able to track quality of care, although the effect size is weak and not consistent for all review website metrics.

Assessing the relationship between volume and outcome in hospital services: implications for service centralization

Proposals for centralizing services are often justified on the basis of studies linking the volume of activity to the outcomes achieved. However, the evidence of such studies is far from demonstrating a causal link between volume and outcome. This article assesses the main reasons why volume and outcome studies do not in themselves demonstrate a causal link, and therefore do not provide adequate support for proposals for centralizing hospital services. It then sets out a number of precepts to guide those responsible for proposing centralization of services.

High-volume centers

Outcome from trauma, surgery, and a variety of other medical conditions has been shown to be positively affected by providing treatment at facilities experiencing a high volume of patients with those conditions. An electronic literature search was made to identify English-language articles available through March 2011, addressing the effect of patient treatment volume on outcome for patients with subarachnoid hemorrhage. Limited data were identified, with 16 citations included in the current review. Over 60% of hospitals fall into the lowest case-volume quartile. Outcome is influenced by patient volume, with better outcome occurring in high-volume centers treating >60 cases per year. Patients treated at low-volume hospitals are less likely to experience definitive treatment. Furthermore, transfer to high-volume centers may be inadequately arranged. Several factors may influence the better outcome at high-volume centers, including the availability of neurointensivists and interventional neuroradiologists.

Basal Cerebral Computed Tomography as Diagnostic Tool to Improve Patient Selection in Asymptomatic Carotid Artery Stenosis

One-hundred patients were included to evaluate the role of cerebral computed tomography (CT) to improve patient selection in asymptomatic internal carotid stenosis. Symptomatic patients were assigned to group A, asymptomatic patients to group B. A cerebral CT pattern A was observed in groups A and B in 60% and 20%, respectively ( P < .0001). Between A and B groups, type 6 plaques were found, respectively, in 26.7% and 7.5% of patients ( P = .01); a type 5 in 51.7% and 45% ( P = .32) of patients; and a type 4 in 21.7% and 47.5% of patients, respectively ( P = .006). Within B group, the association of CT pattern A and histological plaque level 4, 5, and 6 was, respectively, 25% ( P = .15), 50% ( P = .53), and 25% ( P = .16). In group B, a 7-fold risk increase in CT pattern A was found in patients with level 6 plaque. In asymptomatic patients with high-risk plaque, a basal cerebral CT scan can be used as diagnostic tool to improve patient selection for intervention.

Carotid artery stenting: relationship between experience and complication rate

To investigate the evidence for the relationship between volume and outcome for carotid artery stenting. We performed a systematic review of the literature to examine the influence of experience and/or volume on outcome for carotid artery stenting. The primary search strategy was to identify studies presenting year-on-year data. The Pubmed, Embase, Medline and the Cochrane Collaboration databases were searched. Studies with over 100 interventions were included. The main outcome measure compared across studies was all stroke/death. Where possible, comparable data were pooled and analysed using meta-regression techniques. It was not possible to perform a standard systematic review and meta-analysis because of the lack of data from randomised studies. When redundant studies were excluded, four sizeable case series and one registry met the inclusion criteria. When the case series results were pooled, the χ²-test for trend demonstrated a significant reduction in the combined stroke and death rate over time. Meta-regression analysis of case series data allowed the setting of thresholds for 'acceptable' stroke/death rates. Where year-on-year data are available, published stroke and death rates for carotid artery stenting show improvements over time. While advances in technology and pharmacology may in part be responsible, temporal improvement in outcomes demonstrated in both early and contemporary time-frames together with the consistency of the results suggests the presence of a learning curve. In active carotid artery stenting units, it may take almost 2-years before the stroke/death rates fall below an arbitrary 5% threshold.

Analysis of large databases in vascular surgery

Large databases can be a rich source of clinical and administrative information on broad populations. These datasets are characterized by demographic and clinical data for over 1000 patients from multiple institutions. Since they are often collected and funded for other purposes, their use for secondary analysis increases their utility at relatively low costs. Advantages of large databases as a source include the very large numbers of available patients and their related medical information. Disadvantages include lack of detailed clinical information and absence of causal descriptions. Researchers working with large databases should also be mindful of data structure design and inherent limitations to large databases, such as treatment bias and systemic sampling errors. Withstanding these limitations, several important studies have been published in vascular care using large databases. They represent timely, "real-world" analyses of questions that may be too difficult or costly to address using prospective randomized methods. Large databases will be an increasingly important analytical resource as we focus on improving national health care efficacy in the setting of limited resources.

Carotid Artery Stenting in the Nation: The Influence of Hospital and Physician Volume on Outcomes

Objectives: To assess national outcomes of carotid artery stenting (CAS) with respect to hospital and practitioner volume.

Methods: The 2005 to 2006 Nationwide Inpatient Sample (NIS) was used to assess CAS with respect to hospital volume, physician volume, and associated complications. Results: Eighteen thousand five hundred ninety-nine CAS interventions were identified. The top 25% was used to define high-volume hospitals (>60 CAS/2 years) and practitioners (>30 CAS/2 years). The stroke rate after CAS was significantly different between low- and high-volume hospitals (2.35% vs 1.78%, respectively; P = .0206). The stroke rate after CAS was also significantly different between low- and high-volume practitioners (2.19% vs 1.51%, P = .0243). Hospital resource use varied significantly between low- and high-volume hospitals (length of stay [LOS]: 1.64 ± 2.10 vs 1.45 ± 11.21, P = .0006; total charges: $32 261 ± 20 562 vs $30 131 ± 19 592, P = .0047) and practitioners (LOS: 1.70 ± 2.14 vs 1.36 ± 1.36; P < .0001; total charges: $33 762 ± 21 081 vs $23 957 ± 19 713; P < .0001). Conclusions: This analysis demonstrates that hospital and physician volume are associated with outcomes and utilization after CAS. High-volume hospitals and practitioners were associated with lower procedure stroke rates and decreased hospital resource utilization.

Effect of hospital volume on in-hospital mortality for renal artery bypass

BACKGROUND

A recent report determined that the nationwide mortality for renal artery bypass (RAB) is surprisingly high-10%. We hypothesized that operative mortality for RAB is related to the volume of such operations performed in each center.

METHODS

The Nationwide Inpatient Sample was analyzed to identify patients undergoing RAB for the years 2000-2005. In-hospital mortality for RAB was compared between hospitals.

RESULTS

During the study period, RAB was performed on 7413 patients with an overall in-hospital mortality of 9.6%. The multivariate logistic regression analyses revealed that after adjusting for surgical risk, increasing hospital volume was significantly associated with decreased in-hospital mortality for RAB (odds ratio 0.98; 95% confidence interval, 0.96-0.99; P=.015).

CONCLUSIONS

Patient risk profile and hospital volume are critical determinants of in-hospital mortality for RAB, which should be factored into decision making for patients requiring intervention for renovascular disease.

Thirty-Day Outcomes for Carotid Artery Stenting in 6320 Patients From 2 Prospective, Multicenter, High-Surgical-Risk Registries

Background— The American Heart Association has established guidelines for acceptable 30-day death and stroke rates for patients with severe carotid disease undergoing standard-risk carotid endarterectomy: <3% for asymptomatic lesions and <6% for symptomatic lesions. To date, carotid artery stenting has not demonstrated these outcomes in multicenter, prospective assessments of high-surgical-risk patients.

Methods and Results— Data from 2 prospective, multicenter (280 US sites, 672 operators), postmarket surveillance studies in high-surgical-risk patients were analyzed: 2145 patients from the Emboshield and Xact Post Approval Carotid Stent Trial (EX) and 4175 patients from the Carotid ACCULINK/ACCUNET Post Approval Trial to Uncover Rare Events (C2). Both studies had pre- and postprocedure neurological evaluation and independent adjudication of neurological events. The overall 30-day death and stroke rate was 4.1% (95% CI, 3.3% to 5.0%) for EX and 3.4% (95% CI, 2.9% to 4.0%) for C2. In the population comparable with American Heart Association guidelines (<80 years), the combined 30-day death and stroke rate was 5.3% (95% CI, 3.6% to 7.4%) for symptomatic patients and 2.9% (95% CI, 2.4% to 3.4%) for asymptomatic patients, independent of unfavorable risk factors (anatomic or physiologic); in patients ≥80 years, this rate was 10.5% (95% CI, 6.3% to 16.0%) and 4.4% (95% CI, 3.3% to 5.7%), respectively. In subjects with anatomic features unfavorable for surgery, the 30-day death and stroke rates were 1.7% (95% CI, 0.0% to 8.9%) and 2.7% (95% CI, 1.3% to 4.9%) for symptomatic and asymptomatic cohorts, respectively, independent of age.

Conclusions— Outcomes for carotid artery stenting in nonoctogenarian high-surgical-risk patients have improved since the pivotal Food and Drug Administration approval trials, and have achieved American Heart Association standards in both symptomatic and asymptomatic lesions.

Carotid artery stenting: Impact of practitioner specialty and volume on outcomes and resource utilization

OBJECTIVES

A variety of endovascular specialists perform carotid artery stenting (CAS), but little data exist on outcomes and resource utilization among these specialists. We analyzed differences in outcomes after CAS was performed by radiologists (RAD), cardiologists (CRD), and vascular surgeons (VAS).

METHODS

Secondary data analysis of the 2005-2006 State Inpatient Databases for New Jersey were analyzed. Patients with elective admission to the hospital who had CAS procedure <or=2 days after admission were identified. CAS outcomes were analyzed with respect to practitioner specialty and volume, associated complications, and hospital resource utilization.

RESULTS

We identified 625 CAS cases. CRD performed 378 (60.5%), VAS, 199 (31.8%); and RAD, 48 (7.7%). The overall stroke rate was 2.72% and by specialty was CRD, 3.17%; VAS, 2.01%, and RAD, 2.08% (P = .6880). The overall cardiac complication rate was 2.40% (CRD, 2.12%; VAS, 3.02%; RAD, 2.08%; P = .7899). Renal and pulmonary complications were low (0.64% and 0.32%, respectively). Mean hospital length of stay (LOS) in days was significantly shorter for VAS (1.64 +/- 1.40) compared with RAD (2.83 +/- 5.15; P = .0167) and had the same trend compared with CRD (2.14 +/- 3.37; P = .0649). Intensive care unit (ICU) LOS was shorter for VAS (0.52 +/- 0.97) and CRD (0.30 +/- 0.71) than for RAD (2.12 +/- 4.48; P < .0001). The mean total hospital cost was significantly greater for RAD ($20,987 +/- $26,603) and CRD ($18,182 +/- $16,364) than for VAS ($10,000 +/- $4947; P = .0011 and P < .0001, respectively). ICU cost for RAD ($5963 +/- $14,551) was also more than for VAS ($864 +/- $1514; P < .0001) and CRD ($473 +/- $1561; P < .0001). Medical supply costs were significantly greater for CRD ($8772 +/- $9546) than for VAS ($3354 +/- $2261; P < .0001) and RAD ($4964 +/- $2595; P = .0142). Total hospital cost, LOS, and medical supplies were significantly lower for high-volume practitioners vs low-volume practitioners (P < .0001).

CONCLUSION

Stroke rates after CAS did not vary significantly among practitioner specialties. Hospital resource utilization did vary significantly: Vascular surgeons had the lowest utilization of hospital resources for performing CAS. High practitioner volume was associated with lower hospital resource utilization. Elucidation of factors creating resource utilization disparities among endovascular practitioners may lead to improved patient outcomes and permit significant future cost savings for carotid interventions.

Improving quality of care by system change

Change based on evidence