Surgery for asymptomatic carotid stenosis: a study of three patient subgroups

Relationships between 2-Year Survival, Costs, and Outcomes following Carotid Endarterectomy in Asymptomatic Patients in the Vascular Quality Initiative

BACKGROUND

Carotid endarterectomy (CEA) for asymptomatic patients with limited life expectancy may not be beneficial or cost-effective. The purpose of this study was to examine relationships among survival, outcomes, and costs within 2 years following CEA among asymptomatic patients.

METHODS

Prospectively collected data from 3097 patients undergoing CEA for asymptomatic disease from Vascular Quality Initiative VQI registry were linked to Medicare. Models were used to identify predictors of 2-year mortality following CEA. Patients were classified as low, medium, or high risk of death based on this model. Next, we examined costs related to cerebrovascular care, occurrence of stroke, rehospitalization, and reintervention within 2 years following CEA across risk strata.

RESULTS

Overall, 2-year mortality was 6.7%. Age, diabetes, smoking, congestive heart failure (CHF), chronic obstructive pulmonary disease, renal insufficiency, absence of statin use, and contralateral internal carotid artery (ICA) stenosis were independently associated with a higher risk of death following CEA. In-hospital costs averaged $7500 among patients defined as low risk for death, and exceeded $10,800 among high risk patients. Although long-term costs related to cerebrovascular disease were 2 times higher in patients deemed high risk for death compared with low risk patents ($17,800 vs. $8800, P = 0.001), high risk of death was not independently associated with a high probability of high cost. Predictors of high cost at 2 years were severe contralateral ICA stenosis, dialysis dependence, and American Society for Anesthesia Class 4. Both statin use and CHF were protective of high cost.

CONCLUSIONS

Greater than 90% of patients undergoing CEA live long enough to realize the benefits of their procedure. Moreover, the long-term costs are supported by the effectiveness of this procedure at all levels of patient risk.

Benefit of carotid endarterectomy for symptomatic and asymptomatic severe carotid artery stenosis: a Markov model based on data from randomized controlled trials. Clinical article

OBJECT

Several major randomized controlled trials of carotid endarterectomy (CEA) in patients with both symptomatic and asymptomatic carotid artery stenosis have addressed the net effects of CEA on the risk of stroke. However, because the risk of stroke among patients with asymptomatic carotid stenosis is relatively low, whether to treat their stenosis with CEA remains an important public health issue.

METHODS

The authors constructed a Markov model to evaluate the effectiveness of CEA. In modeling 4 health states, the probability of transition to another state was estimated using data from major randomized controlled trials. Adopting 3 comorbidity index values for baseline analyses, the authors expressed outcomes in terms of the expected number of quality-adjusted life years (QALYs) for a hypothetical cohort undergoing CEA and another without treatment.

RESULTS

In the authors' baseline analysis, CEA for asymptomatic stenosis yielded a very small benefit (0.07 QALY) for 70-year-old, normal-risk CEA candidates. Benefits decreased further, often becoming negative, as patient age, surgical risk, or comorbidity index increased. In patients with symptomatic stenosis, CEA was always more effective than conservative management, even considering variables such as comorbidities limiting life expectancy, advanced age, and increased perioperative risk.

CONCLUSIONS

Carotid endarterectomy for severe carotid stenosis consistently and significantly benefits patients with recent symptoms. However, surgery for asymptomatic stenosis appears justified only in carefully selected conditions: low treatment risks in relatively young individuals without any comorbidities.

Long-term survival and stroke-free survival after eversion carotid endarterectomy for asymptomatic severe carotid stenosis

BACKGROUND

Level 1 evidence supports carotid endarterectomy (CEA) as the standard treatment for severe (>70% lumen reduction) carotid stenosis in asymptomatic patients, though its safety and efficacy in high-risk patients remain controversial. Long-term survival and stroke-free survival after CEA may guide decisions concerning this procedure for asymptomatic patients, but this outcome has only been considered in few reports outside the large randomized trial setting. This study analyzed long-term survival and stroke-free survival after CEA and the impact of risk factors in a consecutive series of asymptomatic patients, including those with medical comorbidities and particular anatomical features believed to increase the perioperative morbidity and mortality of CEA.

METHODS

For over 10 years, data were prospectively collected for all patients who underwent CEA for asymptomatic severe carotid disease at our institution. All CEAs performed by the same surgeon involved eversion technique, with patients under deep general anesthesia and continuous perioperative electroencephalographic (EEG) monitoring for selective shunting. All patients had neurological follow-up and duplex ultrasound at 1, 6, and 12 months, and yearly thereafter. A complete follow-up (mean, 6.1 years; range, 0.1 to 10.6 years) was obtained in 348 patients (93%) with an overall 365 CEAs (93%). Survival analyses were performed using Kaplan-Meier life tables.

RESULTS

Among 374 patients undergoing 391 CEAs, there were no perioperative deaths or strokes. There were 17 (4.8%) late deaths, mainly cardiac-related (70%), and 2 (0.5%) non-fatal strokes. At 5 and 10 years, survival was 96.3% and 85.7%, and stroke-free survival was 95.6% and 84.8%, respectively. At multivariate analysis, diabetes mellitus (P = .002) and cardiac disease (P = .005) were independent predictors of a shorter long-term survival.

CONCLUSIONS

Eversion CEA proved safe and effective in a series of patients with asymptomatic severe carotid disease representing the typical population of daily clinical practice. Although long-term results were extremely favorable, excellent stroke-free survival was not translated into a longer patient survival.

Long-Term Survival After Carotid Endarterectomy for Asymptomatic Stenosis

BACKGROUND AND PURPOSE

Large randomized trials have demonstrated a net benefit of carotid endarterectomy (CEA) for asymptomatic carotid artery stenosis compared with best medical treatment. However, it takes years to overcome the perioperative risk and gain the reduction in stroke or death risk. Long-term survival after CEA for asymptomatic stenosis may be an important consideration in deciding on this prophylactic procedure, but is not well documented. The aim was to analyze long-term survival after CEA for asymptomatic stenosis and the impact of risk factors in a population-based study.

METHODS

The Swedish vascular registry (Swedvasc) covers all centers performing CEA. Data on all registered CEAs during 1994 to 2003 were retrieved. All patients were cross-matched with the Population-Registry for accurate data on mortality (date of death). Analyses with Kaplan-Meier curves for survival and relative odds ratio (OR) for predictors of survival were performed.

RESULTS

A total of 6169 CEAs in 5808 patients were registered, with a median time at risk of 5.1 (range, 0.1 to 11.8) years. The indication for CEA was asymptomatic stenosis in 10.8% of the patients. Survival after CEA for asymptomatic stenosis was 78.2% after 5 and 45.5% after 10 years. Previous vascular surgery (OR, 1.8; 1.1 to 3.0), cardiac disease (OR, 1.7; 1.0 to 2.8), diabetes mellitus (OR, 2.3; 1.3 to 4.1), and age (OR, 1.5; 1.1 to 2.1 per 10 years) were predictors of decreased 5-year survival.

CONCLUSIONS

In this population-based study of patients operated on for asymptomatic stenosis, a substantial reduction in long-term survival was observed. Predictors of decreased longevity were age at operation, diabetes, cardiac disease, and previous vascular surgery.

Compromised hemodynamics associated with multipedicular lesions of cerebral arteries

The purpose of this study was to demonstrate that severe multipedicular lesions involving supraaortic trunks cause compromised cerebral hemodynamics with nonhemispheric symptoms (NHS) that can be relieved by surgical treatment. A total of 11 patients were prospectively included in the study. Regional cerebral blood flow (rCBF) and cerebral blood flow reactivity (CBFR) were measured by acetazolamide single photon emission computed tomoscintigraphy scans (SPECT) before and after surgery. Seven patients presented with isolated NHS and four presented with NHS associated with hemispheric symptoms. Lesions consisted of either high-grade (>75%) bilateral carotid artery stenosis associated with vertebral or subclavian artery lesions or high-grade (>75%) bilateral vertebral or subclavian artery stenosis associated with medium-grade (>50%) carotid lesions. All patients presented with a functional circle of Willis with no significant intracranial arterial lesions and no corticosubcortical atrophy. A total of 15 procedures were performed for revascularization of 19 arteries. The cumulative morbidity/mortality rate was nil. All revascularizations were patent on postoperative controls. Results from this study show that multipedicular lesions lead to hemodynamic changes affecting hemispheric and vertebrobasilar territories. Surgical treatment can improve or normalize cerebral hemodynamic abnormalities and relieve NHS.