Regional variation in patient selection and treatment for carotid artery disease in the Vascular Quality Initiative

Regional variation in patient selection, practice patterns, and outcomes based on techniques for carotid artery revascularization in the Vascular Quality Initiative

OBJECTIVE

Significant regional variation is known with multiple surgical procedures. This study describes regional variation in carotid revascularization within the Vascular Quality Initiative (VQI).

METHODS

Data from the VQI carotid endarterectomy (CEA) and carotid artery stenting (CAS) databases from 2016 to 2021 were used. Nineteen geographic VQI regions were divided into three tertiles based on the average annual volume of carotid procedures performed per region (low-volume: 956 cases [range, 144-1382]; medium-volume: 1533 cases [range, 1432-1589]; and high-volume: 1845 cases [range, 1642-2059]). Patients' characteristics, indications for carotid revascularization, practice patterns, and outcomes (perioperative and 1-year stroke/death) of different revascularization techniques were compared between these regional groups. Regression models that adjust for known risk factors and allow for random effects at the center level were used.

RESULTS

CEA was the most common revascularization procedure (>60%) across all regional groups. Significant regional variation was observed in the practice of CEA such as variability in the use of shunting, drain placement, stump pressure and electroencephalogram monitoring, intraoperative protamine, and patch angioplasty. For transfemoral CAS, high-volume regions had a higher proportion of asymptomatic patients with <80% stenosis (30.5% vs 27.8%) in addition to higher use of local/regional anesthesia (80.4% vs 76.2%), protamine (16.1% vs 11.8%), and completion angiography (81.6% vs 77.6%) during transfemoral carotid artery stenting (TF-CAS) compared with low-volume regions. For transcarotid artery revascularization (TCAR), high-volume regions were less likely to intervene on asymptomatic patients with <80% stenosis (32.2% vs 35.8%) than low-volume regions. They also had a higher proportion of urgent/emergent procedures (13.6% vs 10.4%) and were more likely to use general anesthesia (92.0% vs 82.1%), completion angiography (67.3% vs 63.0%), and poststent ballooning (48.4% vs 36.8%). For each carotid revascularization technique, no significant differences were noted in perioperative and 1-year outcomes between low-, medium-, and high-volume regions. Finally, there were no significant differences in outcomes between TCAR and CEA across the different regional groups. In all regional groups, TCAR was associated with a 40% reduction in perioperative and 1-year stroke/death compared with TF-CAS.

CONCLUSIONS

Despite significant variation in clinical practices for the management of carotid disease, no regional variation exists in the overall outcomes of carotid interventions. TCAR and CEA continue to show superior outcomes to TF-CAS across all VQI regional groups.

Distal embolic protection use during transfemoral carotid artery stenting is associated with improved in-hospital outcomes

OBJECTIVE

Despite current guidelines recommending the use of distal embolic protection during transfemoral carotid artery stenting (tfCAS) to prevent periprocedural stroke, there remains significant variation in the routine use of distal filters. We sought to assess in-hospital outcomes in patients undergoing tfCAS with and without embolic protection using a distal filter.

METHODS

We identified all patients undergoing tfCAS in the Vascular Quality Initiative from March 2005 to December 2021 and excluded those who received proximal embolic balloon protection. We created propensity score-matched cohorts of patients who underwent tfCAS with and without attempted placement of a distal filter. Subgroup analyses of patients with failed vs successful filter placement and failed vs no attempt at filter placement were performed. In-hospital outcomes were assessed using log binomial regression, adjusted for protamine use. Outcomes of interest were composite stroke/death, stroke, death, myocardial infarction (MI), transient ischemic attack (TIA), and hyperperfusion syndrome.

RESULTS

Among 29,853 patients who underwent tfCAS, 28,213 (95%) had a filter attempted for distal embolic protection and 1640 (5%) did not. After matching, 6859 patients were identified. No attempted filter was associated with significantly higher risk of in-hospital stroke/death (6.4% vs 3.8%; adjusted relative risk [aRR], 1.72; 95% confidence interval [CI], 1.32-2.23; P < .001), stroke (3.7% vs 2.5%; aRR, 1.49; 95% CI, 1.06-2.08; P = .022), and mortality (3.5% vs 1.7%; aRR, 2.07; 95% CI, 1.42-3.020; P < .001). In a secondary analysis of patients who had failed attempt at filter placement vs successful filter placement, failed filter placement was associated with worse outcomes (stroke/death: 5.8% vs 2.7%; aRR, 2.10; 95% CI, 1.38-3.21; P = .001 and stroke: 5.3% vs 1.8%; aRR, 2.87; 95% CI, 1.78-4.61; P < .001). However, there were no differences in outcomes in patients with failed vs no attempted filter placement (stroke/death: 5.4% vs 6.2%; aRR, 0.99; 95% CI, 0.61-1.63; P = .99; stroke: 4.7% vs 3.7%; aRR, 1.40; 95% CI, 0.79-2.48; P = .20; death: 0.9% vs 3.4%; aRR, 0.35; 95% CI, 0.12-1.01; P = .052).

CONCLUSIONS

tfCAS performed without attempted distal embolic protection was associated with a significantly higher risk of in-hospital stroke and death. Patients undergoing tfCAS after failed attempt at filter placement have equivalent stroke/death to patients in whom no filter was attempted, but more than a two-fold higher risk of stroke/death compared with those with successfully placed filters. These findings support current Society for Vascular Surgery guidelines recommending routine use of distal embolic protection during tfCAS. If a filter cannot be placed safely, an alternative approach to carotid revascularization should be considered.

Increased Regional Market Competition is Associated with a Lower Threshold for Revascularization in Asymptomatic Carotid Artery Stenosis

BACKGROUND

Revascularization practices with respect to asymptomatic carotid stenosis (ACAS) are known to vary widely among proceduralists. In addition, regional market competition has been previously shown to drive more aggressive practices in a number of surgical procedures. The aim of our study was to examine the association of regional market competition with revascularization thresholds for ACAS.

METHODS

All patients undergoing carotid revascularization in the Vascular Quality Initiative carotid endarterectomy and stenting databases (2016-2020) were included. High-grade carotid stenosis was defined as ≥80%. We calculated the Herfindahl-Hirschman Index (HHI; a measure of physician market competition) for each U.S region as defined by the U.S Department of Health and Human Services. Logistic regression was used to examine the association of degree of carotid stenosis at revascularization with HHI stratified by symptomatology, adjusting for age, sex, race, insurance, and revascularization modality.

RESULTS

Of 92,243 carotid interventions, 57,094 (61.9%) were performed for ACAS and 35,149 (38.1%) were performed for symptomatic carotid stenosis (SCAS). ACAS patients undergoing revascularization for moderate-grade stenosis were significantly less likely to be aspirin (85.6% vs. 86.3%), clopidogrel (41.3% vs. 45.1%), dual anti-platelet therapy (35.9% vs. 39.2%) and systemic anticoagulants (10.9 vs. 11.7%) compared to high-grade stenosis (all P < 0.05). Multivariable analysis demonstrated that decreased local market competition was independently associated with a lower odds of revascularization for moderate versus high-grade ACAS (odds ratio OR: 0.99 per 10 point increase in HHI, 95% confidence interval CI: 0.98-0.99). There was no association of local market competition with degree of carotid stenosis at time of revascularization among patients with SCAS (OR: 1.00 per 10 point increase in HHI, 95% CI: 0.99-1.00). Among ACAS patients, patients with moderate-grade stenosis had a higher odds ratio of in-hospital stroke or death compared to patients with high-grade stenosis (OR: 1.22, 95% CI 1.03-1.45). This association was not redemonstrated in the SCAS group (OR: 0.92, 95% CI: 0.80-1.06).

CONCLUSIONS

Increased local market competition is associated with a lower threshold for revascularization of ACAS. There is no association between regional market competition and revascularization threshold for SCAS. These findings, combined with the significantly increased risk of perioperative stroke/death among moderate-grade ACAS patients, suggest that competition among proceduralists may result in a higher tolerance for increased operative risk in patients who might otherwise be reasonable candidates for surveillance.

Impact of implementing good care and management practice guidelines in carotid revascularization procedures

BACKGROUND

Studies assessing the effect of implementing good practice management guidelines (GPMG) in carotid revascularization within the same hospital are scarce. Thus, we aimed to evaluate the impact of GPMG implementation on the clinical outcomes of carotid revascularization procedures within a quaternary hospital.

METHOD

We retrospectively studied 177 patients with atherosclerotic carotid disease who underwent revascularization (carotid endarterectomy and carotid artery stenting) at a quaternary hospital between January 2012 and December 2019. The patients were divided into two groups: the pre-guideline group with 73 patients and the post-guideline group with 104 patients who underwent the procedures before and after the implementation of GPMG, respectively.

RESULTS

Twelve (16.4%) and 3 (2.9%) patients had neurological complications in the pre- and post-guideline groups, respectively (p = 0.001); most complications were cases of ischemic stroke. There were fewer complications in men than in women (OR = 0.22; 95% CI 0.06-0.77). A significant decrease in neurological complications was observed in the carotid artery stenting group (pre-guideline 25.7% vs post-guideline 13.2%; p = 0.004). Logistic regression analysis of the predisposing factors for neurological complications in carotid endarterectomy and carotid artery stenting demonstrated that the implementation of GPMG was a determining factor for the improved results (odds ratio = 0.11, 95% CI 0.02-0.59).

CONCLUSIONS

Implementing GPMG for carotid revascularization resulted in better clinical results, with decreased neurological complications in patients that underwent angioplasty and endarterectomy.

Accurate classification of carotid endarterectomy indication using physician claims and hospital discharge data

BACKGROUND AND PURPOSE

Studies of carotid endarterectomy (CEA) require stratification by symptomatic vs asymptomatic status because of marked differences in benefits and harms. In administrative datasets, this classification has been done using hospital discharge diagnosis codes of uncertain accuracy. This study aims to develop and evaluate algorithms for classifying symptomatic status using hospital discharge and physician claims data.

METHODS

A single center's administrative database was used to assemble a retrospective cohort of participants with CEA. Symptomatic status was ascertained by chart review prior to linkage with physician claims and hospital discharge data. Accuracy of rule-based classification by discharge diagnosis codes was measured by sensitivity and specificity. Elastic net logistic regression and random forest models combining physician claims and discharge data were generated from the training set and assessed in a test set of final year participants. Models were compared to rule-based classification using sensitivity at fixed specificity.

RESULTS

We identified 971 participants undergoing CEA at the Vancouver General Hospital (Vancouver, Canada) between January 1, 2008 and December 31, 2016. Of these, 729 met inclusion/exclusion criteria (n = 615 training, n = 114 test). Classification of symptomatic status using hospital discharge diagnosis codes was 32.8% (95% CI 29-37%) sensitive and 98.6% specific (96-100%). At matched 98.6% specificity, models that incorporated physician claims data were significantly more sensitive: elastic net 69.4% (59-82%) and random forest 78.8% (69-88%).

CONCLUSION

Discharge diagnoses were specific but insensitive for the classification of CEA symptomatic status. Elastic net and random forest machine learning algorithms that included physician claims data were sensitive and specific, and are likely an improvement over current state of classification by discharge diagnosis alone.

Symptom Status of Patients Undergoing Carotid Endarterectomy in Canada and United States

BACKGROUND

Previous studies have demonstrated significant geographic variations in the management of carotid artery stenosis despite standard guidelines. To further characterize these practice variations, we assessed differences in patient selection, operative technique, and outcomes for carotid endarterectomy (CEA) in Canada vs. United States.

METHODS

The Vascular Quality Initiative (VQI) was used to identify all patients who underwent CEA between 2010 and 2019 in Canada and United States. Demographic, clinical, and procedural characteristics were recorded and differences between countries were assessed using independent t-test and chi-square test. The primary outcome was the percentage of CEA performed for asymptomatic versus symptomatic disease. The secondary outcomes were 30-day and long-term stroke or death. Associations between country and outcomes were assessed using univariate/multivariate logistic regression and Cox proportional hazards analysis.

RESULTS

During the study period, 131,411 US patients and 701 Canadian patients underwent CEA in VQI sites. Patients from the US were older with more comorbidities including hypertension, diabetes, congestive heart failure, and chronic kidney disease. The use of a shunt, patch, drain, or protamine was less common in the US. Most patients had 70 - 99% stenosis, with no difference between regions. The percentage of CEA performed for asymptomatic disease was significantly higher in the US even after adjusting for demographic, clinical, and procedural characteristics (72.4% vs. 30.7%, adjusted OR 3.91 [95% CI 3.21 - 4.78], p < 0.001). Thirty-day stroke/death was low (1.8% vs. 1.9%) and 1-year stroke/death was similar between groups (HR 0.98 [95% CI 0.69 - 1.39], P = 0.89). The similarities in 1-year stroke/death persisted in asymptomatic patients (HR 0.70 [95% CI 0.37 - 1.30], P = 0.26) and symptomatic patients (HR 1.14 [95% CI 0.74 - 1.73], P = 0.56).

CONCLUSIONS

There are significant variations in CEA practice between Canada and US. In particular, most US patients are treated for asymptomatic disease, whereas most Canadian patients are treated for symptomatic disease. Furthermore, adjunctive procedures including shunting, patch use, and protamine administration are performed less commonly in the US. Despite these differences, perioperative and 1-year stroke/death rates are similar between countries. Future studies should investigate reasons for these variations and quality improvement projects are needed to standardize care.

Carotid Stenting without Embolic Protection Increases Major Adverse Events: Analysis of the National Surgical Quality Improvement Program

BACKGROUND AND PURPOSE

Published data regarding embolic protection device efficacy is mixed, and its use during carotid artery stent placement remains variable. We, therefore, examined the frequency of embolic protection device use and its association with outcomes after carotid artery stent placement using a national quality improvement data base.

MATERIALS AND METHODS

Patients undergoing carotid artery stent placement with or without embolic protection devices were identified in the American College of Surgeons National Surgical Quality Improvement Program data base. The primary outcome was the incidence of major adverse cardiovascular events (defined as death, stroke, or myocardial infarction/arrhythmia) within 30 days. Propensity scoring was used to create 2 matching cohorts of patients using demographic and baseline variables.

RESULTS

Between 2011 and 2018, among 1200 adult patients undergoing carotid artery stent placement, 23.8% did not have embolic protection devices. There was no trend toward increased embolic protection device use with time. Patients without embolic protection device use received preoperative antiplatelets less frequently (90.6% versus 94.6%, P = .02), underwent more emergent carotid artery stent placement (7.2% versus 3.6%, P = .01), and had a higher incidence of major adverse cardiovascular events (OR = 1.81; 95% CI, 1.11-2.94) and stroke (OR = 3.31; 95% CI, 1.71-6.39). After compensating for baseline imbalances using propensity-matched cohorts (n = 261 for both), carotid artery stent placement without an embolic protection device remained associated with increased major adverse cardiovascular events (9.2% versus 4.2%; OR = 2.30; 95% CI, 1.10-4.80) and stroke (6.5% versus 1.5%; OR = 4.48; 95% CI, 1.49-13.49).

CONCLUSIONS

Lack of embolic protection device use during carotid artery stent placement is associated with a 4-fold increase in the likelihood of perioperative stroke. Nevertheless, nearly one-quarter of patients in the American College of Surgeons National Surgical Quality Improvement Program underwent unprotected carotid artery stent placement. Efforts targeting improved embolic protection device use during carotid artery stent placement are warranted.

Selective Nonoperative and Delayed Management of Severe Asymptomatic Carotid Artery Stenosis

OBJECTIVES

Although intervention is generally the standard of care for severe (80-99%) asymptomatic carotid stenosis, conservative management may be appropriate for a subset of patients. Our goal was to assess reasons for and outcomes of nonoperative/delayed operative management of asymptomatic severe carotid stenosis.

METHODS

Institutional vascular laboratory data from 2010 to 2018 was queried for all patients who underwent a carotid duplex ultrasonography. Patients with severe asymptomatic carotid stenosis (80-99%) were included. Such stenosis was defined by an end diastolic velocity >140 cm/sec on duplex ultrasound in patients without transient ischemic attacks (TIA)/strokes ≤6 months prior to imaging. Nonoperative/delayed operative management was defined as not undergone carotid endarterectomy (CEA) or carotid artery stent (CAS) ≤6 months after imaging. Reasons for nonoperative management or delayed intervention as well as subsequent TIA/stroke and survival were determined. Kaplan-Meier analysis was performed to evaluate survival.

RESULTS

Among 211 patients with severe carotid stenosis, 35 (16.6%) were managed nonoperatively or with delayed operation. Mean age in this subset was 72.6 ± 11.4 years and the majority were female (57.1%), had a smoking history (74.3%), and were on statins (91.4%) at the time of index duplex ultrasound. Reasons for no/delayed intervention were classified as severe medical comorbidities (37.1%), advanced age (17.1%), no referral for intervention (14.3%), patient refusal (14.3%), other severe concomitant cerebrovascular disease (11.4%), and active/advanced cancer (5.7%). Over a median follow-up of 35.2 months, no patients experienced TIAs/strokes attributable to carotid stenosis. One patient had a multifocal bilateral stroke after a cardiac arrest and prolonged resuscitation. A subset of patients underwent delayed CEA (8.6%) or CAS (2.9%). Four-year survival after initial imaging was 79%.

CONCLUSIONS

Reasons for nonoperative and delayed operative management in our cohort of asymptomatic carotid stenosis were commonly due to comorbidities and advanced age. However, a subset of patients was never referred to vascular surgeons/interventionalists. Adverse neurologic events due to carotid stenosis were not observed during follow-up and patients had relatively high long-term survival.

Pro B-type Natriuretic Peptide and Midregional Proadrenomedullin are Associated with Incident Carotid Stenosis During Long Term Follow-up

BACKGROUND

Plasma biomarkers may be useful to detect healthy individuals at increased risk for atherosclerotic manifestations, such as carotid artery stenosis. The aim of this longitudinal cohort study was to evaluate new biomarkers in relation to C-reactive protein and conventional risk factors for carotid artery stenosis during long term follow-up METHODS: The following markers were measured in 5550 middle-aged subjects: C-reactive protein, lipoprotein-associated phospholipase A2, proneurotensin, midregional pro-adrenomedullin, midregional pro-atrial natriuretic peptide, N-terminal pro B-type natriuretic peptide, copeptin, and cystatin C. Subjects with prevalent carotid artery stenosis were excluded. Subjects were followed in national patient registers for 23.4 (interquartile range 19.5-24.3) years regarding incident carotid artery stenosis, both operated and non-operated.

RESULTS

When including conventional risk markers in Cox regression, N-terminal pro B-type natriuretic peptide (Hazard ratio 1.36; 95% confidence interval 1.12-1.65; p = 0.002) was independently associated with incident carotid artery stenosis, whereas there were trends for C-reactive protein (HR 1.20; 95% confidence interval 0.98-1.48; p = 0.071), and midregional pro-adrenomedullin (Hazard ratio 1.21; 95% confidence interval 0.99-1.47; p = 0.061). Midregional pro-adrenomedullin (Hazard ratio 1.30; 95% confidence interval 1.03-1.65; p = 0.029) was independently associated with incident surgery for carotid artery stenosis, whereas there was a trend for N-terminal pro B-type natriuretic peptide (Hazard ratio 1.31; 95% confidence interval 1.00-1.72; p = 0.052).

CONCLUSIONS

N-terminal pro B-type natriuretic peptide and midregional pro-adrenomedullin can be used as predictors for clinically detected carotid artery stenosis during long-term follow-up of healthy subjects.

Contemporary Trends in Physician Utilization Rates of CEA and CAS for Asymptomatic Carotid Stenosis among Medicare Beneficiaries

BACKGROUND

Carotid revascularization for asymptomatic carotid artery stenosis (ACAS) has become increasingly controversial in the past few decades as the best medical therapy has improved. The aim of this study was to assess and define contemporary trends in the rate of carotid revascularization procedures for ACAS in the United States and to characterize outlier physicians performing a higher rate of asymptomatic revascularization compared to their peers.

METHODS

We used 100% Medicare fee-for-service claims to identify all patients who were newly diagnosed with ACAS between 01/2011-06/2018. Patients with symptomatic carotid artery stenosis, those with prior carotid revascularization, and surgeons who performed ≤10 CEAs during the study period were excluded. We used a hierarchical multivariable logistic regression model to evaluate patient and physician characteristics associated with undergoing a carotid endarterectomy or carotid artery stent procedure within 3 months after the initial diagnosis of ACAS. We also assessed temporal trends in carotid revascularization rates over time using the Cochran-Armitage Trend Test.

RESULTS

Overall, 795,512 patients (median age 73.9 years, 50.9% male, 87.6% white) had a first-time diagnosis of ACAS during the study period, of which 23,481 (3.0%) underwent carotid revascularization within 3 months. There was a significant decline in overall carotid artery revascularization rates over time (2011: 3.2% vs. 2018: 2.1%; P < 0.001). The median and mean physician-specific carotid revascularization rates were 2.0% (IQR 0.0%-6.3%) and 4.7% ± 7.1%, respectively. Three-hundred and fifty physicians (5.2%) had carotid revascularization rates ≥19%, which was more than 2 standard deviations above the mean. After adjusting for patient-level characteristics, physician-level variables associated with carotid revascularization for newly diagnosed ACAS included male sex (adjusted OR 1.59, 95% CI 1.35-1.89), more years in practice (≥31 vs. <10 years, aOR 1.64, 95% CI 1.32-2.04), rural practice location (aOR 1.34, 95% CI 1.18-1.52), Southern region practice location (versus Northeast, aOR 1.54, 95% CI 1.39-1.69), and lower volume of ACAS patients (lower versus upper tertile, aOR 2.62, 95% CI 2.39-2.89). Cardiothoracic surgeons had a 1.52-fold higher odds of carotid revascularization compared to vascular surgeons (95% CI 1.36-1.68), whereas cardiologists and radiologists had lower intervention rates (both, P < 0.05).

CONCLUSIONS

The current early revascularization rate for newly diagnosed ACAS is <5% among proceduralists in the United States, and has been decreasing steadily since 2014. There are particular physician-level characteristics that are associated with higher rates of carotid revascularization that cannot be fully contextualized without high-level contemporary outcomes data to guide decision making in ACAS.

Risk factors and impact of postoperative hypotension after carotid artery stenting in the Vascular Quality Initiative

OBJECTIVE

Hypotension is a frequent complication of carotid artery stenting (CAS). Although common, its occurrence is unpredictable, and association with adverse events has not been well defined. The aim of this study was to identify predictors of postoperative hypotension after CAS and the association with stroke/transient ischemic attack (TIA), major adverse cardiac events (MACEs), increased length of stay (LOS), and in-hospital mortality.

METHODS

This is a retrospective analysis of all CAS procedures, including transfemoral CAS (TF-CAS) and transcarotid artery revascularization (TCAR), performed in the Vascular Quality Initiative between 2003 and 2018. The primary study end point was postoperative hypotension, defined as hypotension treated with continuous infusion of a vasoactive agent for ≥15 minutes. Secondary end points included any postoperative neurologic events (stroke/TIA), MACEs (myocardial infarction, congestive heart failure, and dysrhythmias), prolonged LOS (>1 day), and in-hospital mortality. Patients' demographics predictive of hypotension were determined by multivariable logistic regression, and a risk score was developed for correlation with outcomes.

RESULTS

During the time period of study, 24,699 patients underwent CAS; 19,716 (80%) were TF-CAS, 3879 (16%) were TCAR, and 1104 (4%) were not defined. Fifty-six percent were for symptomatic disease, 75% were for a primary atherosclerotic lesion, and 72% were performed under local or regional anesthesia. Postoperative hypotension occurred in 15% of TF-CAS and 14% of TCAR patients (P = .50). Patients with hypotension (vs no hypotension) had higher rates of stroke/TIA (7.3% vs 2.6%; P < .001), MACEs (9.6% vs 2.1%; P < .001), prolonged LOS (65% vs 28%; P < .001), and in-hospital mortality (2.9% vs 0.7%; P < .001). By multivariable analysis, risk factors associated with hypotension included an atherosclerotic (vs restenotic) lesion (odds ratio, 2.2; 95% confidence interval, 2.0-2.4; P < .001), female sex (1.3 [1.2-1.4]; P < .001), positive stress test result (1.3 [1.2-1.4]; P < .001), age 70 to 79 years (1.1 [1.1-1.3]; P < .002), age >80 years (1.2 [1.1-1.4]; P < .001), history of myocardial infarction or angina (1.3 [1.2-1.4]; P < .001), and an urgent (vs elective) procedure (1.1 [1.0-1.2]; P < .01). A history of hypertension was protective (0.9 [0.8-0.9]; P < .02). A normalized risk score for hypotension was created from the multivariable model. Increasing risk scores correlated directly with rates of adverse events, including postoperative stroke/TIA, MACEs, increased LOS, and increased in-hospital mortality.

CONCLUSIONS

Hypotension after CAS is associated with adverse neurologic and cardiac events as well as with prolonged LOS and in-hospital mortality. A scoring tool may be valuable in stratifying patients at risk. Interventions aimed at preventing postoperative hypotension may improve outcomes with CAS.

Natural History of Non-operative Management in Asymptomatic Patients with 70%-80% Internal Carotid Artery Stenosis by Duplex Criteria

OBJECTIVE

Treatment of asymptomatic internal carotid artery (ICA) stenosis, particularly for moderate to severe (70%-80%) disease, is controversial. The goal was to assess the clinical course of patients with moderate to severe carotid stenosis.

METHODS

A single institution retrospective analysis of patients with asymptomatic ICA stenosis identified on duplex ultrasound as moderate to severe (70%-80%) from 2003 to 2018 were analysed. Duplex criteria for 70%-80% stenosis was a systolic velocity of ≥325 cm/s or an ICA:common carotid artery ratio of ≥4, and an end diastolic velocity of <140 cm/s. Asymptomatic status was defined as no stroke/transient ischaemic attack (TIA) within six months of index duplex. Primary outcomes were progression of stenosis to >80%, ipsilateral stroke/TIA without documented progression, and death.

RESULTS

In total, 206 carotid arteries were identified in 182 patients meeting the inclusion criteria. Mean patient age was 71.5 years, 57.7% were male, and 67% were white. There were 19 stenoses removed from analysis except for survival analysis as they initially underwent carotid endarterectomy or carotid artery stent based on surgeon/patient preference. Documented progression occurred in 24.1% of stenoses. There were 5.3% of stenoses associated with an ipsilateral stroke/TIA without documented progression, which occurred at a mean of 26.4 months. Kaplan-Meier analysis demonstrated a 60.3% five year freedom from stenosis progression, 92.5% five year freedom from stroke/TIA without documented progression, and 83.7% five year survival. Risk factors associated with stroke/TIA without documented progression at five years were atrial fibrillation (hazard ratio [HR] 14.87, 95% confidence interval [CI] 2.72-81.16; p = .002) and clopidogrel use at index duplex (HR 6.19, 95% CI 1.33-28.83; p = .020). Risk factors associated with death at five years were end stage renal disease (HR 9.67, 95% CI 2.05-45.6; p = .004), atrial fibrillation (HR 7.55, 95% CI 2.48-23; p < .001), prior head/neck radiation (HR 6.37, 95% CI 1.39-29.31; p = .017), non-obese patients (HR 5.49, 95% CI 1.52-20; p = .009), and non-aspirin use at index duplex (HR 3.05, 95% CI 1.12-8.33; p = .030).

CONCLUSION

Patients with asymptomatic moderate to severe carotid stenosis had a low rate of stroke/TIA without documented progression. However, there was a high rate of stenosis progression reinforcing the need to follow these patients closely.

Regional variation in use and outcomes of combined carotid endarterectomy and coronary artery bypass

OBJECTIVE

In treating concomitant carotid and coronary disease, some recommend staged carotid endarterectomy (CEA) and coronary artery bypass grafting, whereas others favor the combined approach (CCAB). Pressure to reduce surgical variation and to improve quality is real, yet little is known about how geographic practice differences affect outcomes. Using the Vascular Quality Initiative (VQI), this study evaluated regional variation in use and outcomes of CCAB.

METHODS

All CCAB procedures in the VQI from 2003 to 2017 were reviewed and stratified into four regions, as defined by the United States Census Bureau. Primary outcomes included perioperative stroke, death, myocardial infarction (MI), and these as composite (SDM). A χ² analysis was performed.

RESULTS

There were 1495 CCAB procedures identified, representing 1.8% of the VQI CEAs. Regions included the following: Midwest (MW), 32%; Northeast (NE), 39%; South (S), 25%; and West (W), 4%. Most were male (70%) and white (92%). There was significant regional variation in proportional volume of CCABs to all CEAs (0.7% [W] to 2.5% [MW]; P < .001). Regional variation in patch use (78% [W] to 93% [MW]; P < .001), shunting (29% [W] to 71% [MW]; P < .001), and electroencephalography monitoring (13% [W] to 52% [NE]; P < .001) was also significant. Overall perioperative stroke was 3.6%; death, 3.0%; and SDM, 6.8%. No regional difference was seen in outcomes of mortality (1.5% [MW] to 4.2% [NE]; P = .05), stroke (2.8% [NE] to 4.4% [MW]; P = .52), and MI (0.6% [MW] to 1.8% [W]; P = .62). When the Bonferroni correction was used, there remained no difference in stroke, MI, or SDM across regions, but mortality became significant. Using the Society for Vascular Surgery guidelines for consideration of CCAB, the minority of patients fell within the symptomatic carotid stenosis (SYMP, 15%; n = 218) or severe (≥70%) asymptomatic bilateral carotid disease (BIL, 18%; n = 267) categories. The most common indication was asymptomatic unilateral severe carotid stenosis (UNI, 37%; n = 552). There were no differences in regional outcomes stratified by indication (SYMP, BIL, UNI). Overall, when SYMP and BIL were compared with UNI, UNI had lower rates of stroke (2.4% vs 4.9%; P = .03) but similar MI (0.7% vs 1.2%; P = .40) and mortality (2.2% vs 2.5%; P = .75).

CONCLUSIONS

Significant variation exists across VQI centers in the use of CCAB. Despite differences in volume and practices, regional perioperative outcomes are similar. UNI is the most commonly used indication and has lower stroke rates relative to SYMP and BIL. CCAB is performed well across the United States, but most patients fall outside of Society for Vascular Surgery guidelines.

Regional frequency variation of revascularization procedures for carotid stenosis in Germany: Secondary data analysis of DRG data from 2012 to 2014

Background

For Germany, regional variation of procedure rates of carotid endarterectomy (CEA) and carotid artery stenting (CAS) performed for carotid stenosis have so far not been analyzed at a national level. The aim of this study was to assess small area estimates of procedure rates among German regions, and to identify regional characteristics, which are associated with the regional frequency of procedures.

Methods

German diagnosis-related groups (DRG) statistics (2012-2014) were analyzed. Inclusion and exclusion criteria for procedural codes were set according to German quality assurance measures in combination with the diagnosis of carotid stenosis (I65.2). Rates of CEA and CAS were indirectly standardized for sex and age.

Results

In total, 88,182 procedures were performed (73,042 CEA; 15,367 CAS). The overall procedure rate varied between 13.2 per 100,000 (Augsburg) and 89.2 per 100,000 (Wilhelmshaven). Spatial analysis revealed that regional distribution was significantly clustered.

Conclusion

The rates of CEA, and especially of CAS showed high regional variation. The spatial distribution was significantly clustered. In addition to the regional prevalence of diabetes mellitus, smoking and obesity, socioeconomic factors, such as income and debts were correlated with the overall frequency of CEA and CAS. No significant association was found between indicators of health infrastructure (e. g. density of hospital beds, vascular surgeons and angiologists) and the overall procedure rate.

Regional variation in patient outcomes in carotid artery disease treatment in the Vascular Quality Initiative

OBJECTIVE

Quality metrics were developed to improve outcomes after carotid artery revascularization; however, few studies have evaluated regional differences in perioperative outcomes. This study aimed to evaluate regional variation in mortality and perioperative outcomes after carotid endarterectomy (CEA) and carotid artery stenting (CAS).

METHODS

We identified all patients who underwent CEA or CAS from 2009 to 2016 in the Vascular Quality Initiative. Patients were analyzed on the basis of their symptom status. We assessed variation in perioperative outcomes using χ² analysis, Fisher exact test, and t-test, where appropriate.

RESULTS

A total of 78,467 carotid interventions were identified; 85% were CEAs, with 69% of those asymptomatic. Within CAS, 39% were asymptomatic. Perioperative stroke/death varied across regions within both CAS groups (asymptomatic, 0%-5.8% [P = .03]; symptomatic, 2.4%-8.1% [P = .1]), and several regions did not meet the American Heart Association (AHA) guidelines of 3% for asymptomatic patients and 6% for symptomatic patients, which persisted after risk adjustment. For CEA, the stroke/death rates fell within the standards set by the AHA guidelines in all regions for both the unadjusted and risk-adjusted models; however, there was significant regional variation in the cohorts (asymptomatic, 0.9%-3.1% [P < .01]; symptomatic, 1.3%-4.9% [P < .01]). Variation in 30-day mortality was significant in symptomatic patients (asymptomatic: CEA, 0%-1.3% [P = .2], CAS, 0%-2.4% [P = .2]; symptomatic: CEA, 0%-1.8% [P < .01], CAS, 0%-4.6% [P = .01]). Rates of in-hospital stroke, postoperative myocardial infarction, prolonged length of stay (>2 days), and use of intravenous blood pressure medications all varied significantly across the regions. After CEA, there was significant variation in the rates of cranial nerve injuries (asymptomatic, 0.9%-4.9% [P < .01]; symptomatic, 1.5%-7.7% [P < .01]), return to the operating room (asymptomatic, 0.9%-3.4% [P < .01]; symptomatic, 0.6%-3.4% [P = .02]), and discharge on antiplatelet and statin (asymptomatic, 75%-87% [P < .01]; symptomatic, 78%-91% [P < .01]). After CAS, significant variation was found in the rates of access site complications (asymptomatic, 2.3%-18.2% [P < .01]; symptomatic, 1.4%-16.9% [P < .01]) and discharge on dual antiplatelet therapy (asymptomatic, 79%-94% [P < .01]; symptomatic, 83%-93% [P < .01]).

CONCLUSIONS

Unwarranted regional variation exists in outcomes after carotid artery revascularization across the regions of the VQI. Significant variation was seen in a number of outcomes for which quality metrics currently exist, such as length of stay and discharge medications. In addition, after CAS, several regions failed to meet the AHA guidelines for stroke and death. Given these results, quality improvement projects should be targeted to improve adherence to current guidelines to promote best practices.

Regional variation in racial disparities among patients with peripheral artery disease

OBJECTIVE

Prior studies identified significant racial disparities as well as regional variation in outcomes of patients with peripheral artery disease (PAD). We aimed to determine whether regional variation contributes to these racial disparities.

METHODS

We identified all white or black patients who underwent infrainguinal revascularization or amputation in 15 deidentified regions of the Vascular Quality Initiative between 2003 and 2017. We excluded three regions with <100 procedures. We used multivariable linear regression, allowing clustering at the hospital level to calculate the marginal effects of race and region on adjusted 30-day mortality, major adverse limb events (MALEs), and amputation. We compared long-term outcomes between black and white patients within each region and within patients of each race treated in different regions using multivariable Cox regression.

RESULTS

We identified 90,418 patients, 15,527 (17%) of whom were black. Patients underwent 31,263 bypasses, 52,462 endovascular interventions, and 6693 amputations. Black patients were younger and less likely to smoke, to have coronary artery disease, or to have chronic obstructive pulmonary disease, but they were more likely to have diabetes, limb-threatening ischemia, dialysis dependence, and hypertension and to be self-insured or on Medicaid (all P < .05). Adjusted 30-day mortality ranged from 1.2% to 2.1% across regions for white patients and 0% to 3.0% for black patients; adjusted 30-day MALE varied from 4.0% to 8.3% for white patients and 2.4% to 8.1% for black patients; and adjusted 30-day amputation rates varied from 0.3% to 1.2% for white patients and 0% to 2.1% for black patients. Black patients experienced significantly different (both higher and lower) adjusted rates of 30-day mortality and amputation than white patients did in several regions (P < .05) but not MALEs. In addition, within each racial group, we found significant variation in the adjusted rates of all outcomes between regions (all P < .01). In adjusted analyses, compared with white patients, black patients experienced consistently lower long-term mortality (hazard ratio [HR], 0.80; 95% confidence interval [CI], 0.73-0.88; P < .001) and higher rates of MALEs (HR, 1.15; 95% CI, 1.06-1.25; P < .001) and amputation (HR, 1.33; 95% CI, 1.18-1.51; P < .001), with no statistically significant variation across the regions. However, rates of all long-term outcomes varied within both racial groups across regions.

CONCLUSIONS

Significant racial disparities exist in outcomes after lower extremity procedures in patients with PAD, with regional variation contributing to perioperative but not long-term outcome disparities. Underperforming regions should use these data to generate quality improvement projects, as understanding the etiology of these disparities is critical to improving the care of all patients with PAD.