Impact of Provider Characteristics on Outcomes of Carotid Endarterectomy for Asymptomatic Carotid Stenosis in New York State

Carotid endarterectomy surgeon volumes in contemporary practice: A comparison to randomized trial inclusion criteria

BACKGROUND

Clinical decisions regarding the utility of carotid revascularization are informed by randomized controlled trial (RCT) results. However, RCTs generally require participating surgeons to meet strict inclusion criteria with respect to procedure volume. The purpose of this study was to compare annual surgeon volume for carotid endarterectomy (CEA) in contemporary practice to RCT inclusion thresholds.

METHODS

Surgeon volume thresholds were identified in 17 RCTs evaluating the efficacy of CEA (1986-present, n = 17). Contemporary annual surgeon volumes (2012-2017) were identified by aggregating data from the Medicare Provider Utilization Database and Healthcare Cost and Utilization Project Network (HCUP), and compared to RCT inclusion thresholds. Further comparisons were performed over time, and across specialties (i.e., vascular surgeon vs. other, based on board certification associated with provider NPI).

RESULTS

Minimal surgeon volume in 17 RCTs ranged from 10 to 25 CEA annually when specific case volumes were required. From 2012 to 2017, CEA incidence in Medicare beneficiaries declined from 68,608 to 56,004 and became increasingly consolidated in fewer providers (7,331 vs. 6,626). However, in 2016 only 26.2% of surgeons performing CEA in Medicare beneficiaries would have met the least stringent volume requirement (10 CEA/year). Only 6.5% of surgeons performing CEA met the most stringent RCT volume threshold (25 cases/year) during the same time period. In 2017, 819 vascular surgeons (25.5% of those certified in the specialty) performed >10 CEA in Medicare beneficiaries.

CONCLUSIONS

The majority of surgeons performing CEA do not meet the annual volume thresholds required for participation in the RCTs that have evaluated the efficacy of carotid revascularization. Given the established volume-outcome relationship in CEA, the disparity between surgeon experience in the context of RCTs versus contemporary practice is concerning. These findings have potential implications for informed decision-making, hospital privileging, and regionalization of care.

A systematic review and meta-analysis of complication rates after carotid procedures performed by different specialties

OBJECTIVE

Different competencies and skills are required and obtained during medical specialization. However, whether these have an impact on procedural outcomes of carotid endarterectomy (CEA) or carotid artery stenting (CAS) is unclear. We assessed the reported association between operator specialization and procedural outcomes after CEA or CAS to determine whether CEA and CAS should be performed by specific specialties.

METHODS

We systematically searched PubMed and Embase up to August 21, 2017, for randomized clinical trials and observational studies that compared two or more specialties performing CEA or CAS for symptomatic and asymptomatic carotid artery stenosis. The composite primary outcome was procedural stroke or death (ie, occurring within 30 days of the procedure or before discharge). Risk estimates were pooled with a generic inverse variance random effects model.

RESULTS

A total of 35 studies (26 providing data on CEA, 8 providing data on CAS, and 1 providing data on both CEA and CAS) were included, describing 256,033 CEA and 38,605 CAS procedures. For CEA, decreased risk of procedural stroke or death for operations performed by vascular surgeons was found with pooled unadjusted relative risk (RR) of 0.63 (95% confidence interval [CI], 0.46-0.86; seven studies) compared with neurosurgeons and RR of 0.81 (95% CI, 0.66-0.99; six studies) compared with general surgeons. An increased risk of procedural stroke or death for operations performed by neurosurgeons compared with cardiothoracic surgeons was found with a pooled unadjusted RR of 1.22 (95% CI, 1.02-1.46). No studies adjusted for potential confounding, and no significant unadjusted associations were found in other comparisons of operator specialty for the primary outcome. For CAS, no differences in procedural stroke or death were found by operator specialty.

CONCLUSIONS

Studies were at high risk of bias mainly because of potential confounding by patient selection for CEA and CAS. Current evidence is insufficient to restrict CEA or CAS to specific specialties.

Reframing the Biological Basis of Neuroprotection Using Functional Genomics: Differentially Weighted, Time-Dependent Multifactor Pathogenesis of Human Ischemic Brain Damage

Background: Neuroprotection studies are generally unable to demonstrate efficacy in humans. Our specific hypothesis is that multiple pathophysiologic pathways, of variable importance, contribute to ischemic brain damage. As a corollary to this, we discuss the broad hypothesis that a multifaceted approach will improve the probability of efficacious neuroprotection. But to properly test this hypothesis the nature and importance of the multiple contributing pathways needs elucidation. Our aim is to demonstrate, using functional genomics, in human cardiac surgery procedures associated with cerebral ischemia, that the pathogenesis of perioperative human ischemic brain damage involves the function of multiple variably weighted proteins involving several pathways. We then use these data and literature to develop a proposal for rational design of human neuroprotection protocols.

Methods: Ninety-four patients undergoing deep hypothermic circulatory arrest (DHCA) and/or aortic valve replacement surgery had brain damage biomarkers, S100β and neurofilament H (NFH), assessed at baseline, 1 and 24 h post-cardiopulmonary bypass (CPB) with analysis for association with 92 single nucleotide polymorphisms (SNPs) (selected by co-author WAK) related to important proteins involved in pathogenesis of cerebral ischemia.

Results: At the nominal significance level of 0.05, changes in S100β and in NFH at 1 and 24 h post-CPB were associated with multiple SNPs involving several prospectively determined pathophysiologic pathways, but were not individually significant after multiple comparison adjustments. Variable weights for the several evaluated SNPs are apparent on regression analysis and, notably, are dissimilar related to the two biomarkers and over time post CPB. Based on our step-wise regression model, at 1 h post-CPB, SOD2, SUMO4, and GP6 are related to relative change of NFH while TNF, CAPN10, NPPB, and SERPINE1 are related to the relative change of S100B. At 24 h post-CPB, ADRA2A, SELE, and BAX are related to the relative change of NFH while SLC4A7, HSPA1B, and FGA are related to S100B.

Conclusions: In support of the proposed hypothesis, association SNP data suggest function of specific disparate proteins, as reflected by genetic variation, may be more important than others with variation at different post-insult times after human brain ischemia. Such information may support rational design of post-insult time-sensitive multifaceted neuroprotective therapies.