Predicting risk of perioperative death and stroke after carotid endarterectomy in asymptomatic patients: derivation and validation of a clinical risk score

Abstract

Background and purpose: National guidelines on carotid endarterectomy (CEA) for asymptomatic patients state that the procedure should be performed with a ≤ 3% risk of perioperative death or stroke. We developed and validated a multivariate model of risk of death or stroke within 30 days of CEA for asymptomatic disease and a related clinical prediction rule.

Methods: We analyzed asymptomatic cases in a population-based cohort of CEAs performed in Medicare beneficiaries in New York State. Medical records were abstracted for sociodemographics, neurologic history, disease severity, diagnostic imaging data, comorbidities, and deaths and strokes within 30 days of surgery. We used multivariate logistic regression to identify independent predictors of perioperative death or stroke. The CEA-8 clinical risk score was derived from the final model.

Results: Among the 6553 patients, the mean age was 74 years, 55% were male, 62% had coronary artery disease, and 22% had a history of distant stroke or transient ischemic attack. The perioperative rate of death or stroke was 3.0%. Multivariable predictors of perioperative events were female sex (odds ratio [OR] = 1.5; 95% CI, 1.1 to 1.9), nonwhite race (OR = 1.8; 95% CI, 1.1 to 2.9), severe disability (OR = 3.7; 95% CI, 1.8 to 7.7), congestive heart failure (OR = 1.6; 95% CI, 1.1 to 2.4), coronary artery disease (OR = 1.6; 95% CI, 1.2 to 2.2), valvular heart disease (OR = 1.5; 95% CI, 1.1 to 2.3), a distant history of stroke or transient ischemic attack (OR = 1.5; 95% CI, 1.1 to 2.0), and a nonoperated stenosis ≥ 50% (OR = 1.8; 95% CI, 1.3 to 2.3). The CEA-8 risk score stratified patients with a predicted probability of death or stroke rate from 0.6% to 9.6%.

Conclusions: Several sociodemographic, neurologic severity, and comorbidity factors predicted the risk of perioperative death or stroke in asymptomatic patients. The CEA-8 risk score can help clinicians calculate a predicted probability of complications for an individual patient to help inform the decision about revascularization.

Figure 1

Figure 1-A: Performance of Multivariable Model of Perioperative Death and Stroke in Training (Derivation) and Testing (Validation) Datasets Observed rates of death or stroke within 30 days of carotid endarterectomy stratified by quintiles of predicted risk derived from the final multivariable model. Quintile 1 is the lowest quintile of predicted risk and Quintile 5 the highest. Black bars are results from the training database and gray bars from the testing database. Figure 1-B: Performance of Multivariable Model of Any Stroke in Derivation and Validation Datasets Observed rates of any stroke (fatal or non-fatal) within 30 days of carotid endarterectomy stratified by quintiles of predicted risk derived from the final multivariable model. Quintile 1 is the lowest quintile of predicted risk and Quintile 5 the highest. Black bars are results from the training database and gray bars from the testing database.

Figure 1

Figure 1-A: Performance of Multivariable Model of Perioperative Death and Stroke in Training (Derivation) and Testing (Validation) Datasets Observed rates of death or stroke within 30 days of carotid endarterectomy stratified by quintiles of predicted risk derived from the final multivariable model. Quintile 1 is the lowest quintile of predicted risk and Quintile 5 the highest. Black bars are results from the training database and gray bars from the testing database. Figure 1-B: Performance of Multivariable Model of Any Stroke in Derivation and Validation Datasets Observed rates of any stroke (fatal or non-fatal) within 30 days of carotid endarterectomy stratified by quintiles of predicted risk derived from the final multivariable model. Quintile 1 is the lowest quintile of predicted risk and Quintile 5 the highest. Black bars are results from the training database and gray bars from the testing database.

Figure 2

Figure 2-A: Perioperative Death or Stroke According to CEA-8 Clinical Risk Score (8 Factors) Observed rates of death or stroke within 30 days of carotid endarterectomy according to number of risk points from the CEA-8 Clinical Risk Score (8 factor version) Figure 2-B: Perioperative Death or Stroke According to Patient Friendly Risk Score (7 Factors) Observed rates of death or stroke within 30 days of carotid endarterectomy according to number of risk points from Patient Friendly CEA-7 Risk Score (7 factor version)

Figure 2

Figure 2-A: Perioperative Death or Stroke According to CEA-8 Clinical Risk Score (8 Factors) Observed rates of death or stroke within 30 days of carotid endarterectomy according to number of risk points from the CEA-8 Clinical Risk Score (8 factor version) Figure 2-B: Perioperative Death or Stroke According to Patient Friendly Risk Score (7 Factors) Observed rates of death or stroke within 30 days of carotid endarterectomy according to number of risk points from Patient Friendly CEA-7 Risk Score (7 factor version)