Carotid endarterectomy: the "gold standard" in the endovascular era

Trends in the in-hospital stroke rate following carotid endarterectomy in California and Maryland

OBJECTIVE

We examined the outcome of carotid endarterectomy (CEA) in the state of Maryland during the last decade to identify any trends in the incidence of in-hospital stroke and mortality and compared these results with the outcome of the operation throughout the state of California as a control population.

METHOD

We performed a retrospective analysis of 10 years (1994 to 2003) of the Maryland and 5 years (1999 to 2003) of the California hospital discharge databases. The following patients were included in the analysis: (1) International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure code 38.12 (endarterectomy of the vessels of the head and neck other than intracranial vessels) in the primary coding position but not in any secondary position, or (2) the diagnosis code 433.00 to 433.91 (occlusion/stenosis, precerebral artery), or (3) the diagnosis-related group (DRG) 5 (extracranial vascular procedure). Symptomatic patients were identified by history of previous stroke (ICD-9 codes 342 or 438), transient ischemic attack (435 or 781.4), or amaurosis fugax (362.34 or 368.12). In-hospital strokes were identified by ICD-9 codes 997.0, 997.00, 997.01, and 997.09. Low-, moderate-, and high-volume surgeons were defined as performing <15, 15 to 74 and >or=75 CEAs annually. Hospital volumes were similarly classified as low for those performing <or=20 CEAs, moderate for 21 to 100, and high for >100 annually.

RESULTS

In the Maryland data, 23,237 CEA cases were identified with 169 in-hospital strokes over 10 years (0.73%), whereas the 51,331 California CEAs had 232 in-hospital strokes over 5 years (0.45%). The stroke rate in Maryland was 2.12% in 1994, 1.47% in 1995, and 0.29% to 0.65% from 1996 to 2003. The decrease in strokes was more pronounced among symptomatic patients, where the rate was 3.82% in 1994, 4.44% in 1995, and 0.90% to 2.29% from 1996 to 2003. A similar decrease was identified in the asymptomatic patient population but was less pronounced: 1.64% in 1994, 0.81% in 1995, and 0.15% to 0.44% from 1996 to 2003. The low recent stroke rates were confirmed by the California data (0.44% to 0.48% from 1999 to 2003). Changes in the death rate for CEA during this time frame have not been as pronounced, from 0.33% to 0.58% for Maryland and 0.78% to 0.91% for California.

CONCLUSIONS

A dramatic decrease in the in-hospital stroke rates in Maryland occurred around 1995. The stroke rates in Maryland in the past 5 years are similar to those in California during the same period. An analysis of data from the two states shows that the in-hospital stroke rate now for carotid endarterectomy is approximately 0.54%.

A preliminary clinical scale to predict the risk of in-hospital death after carotid endarterectomy

OBJECTIVE

Carotid endarterectomy (CEA) remains the gold standard for the treatment of carotid disease, with mortality rates generally at 0.4% to 1.7%. Controversy remains with regards to its role in the treatment of the high-risk surgical population. We developed a new clinical scale incorporating weighted risk factors into a single numerical score that correlates with the risk of in-hospital death after CEA. We propose that this tool may serve to prospectively identify the high-risk patient.

METHODS

We performed a retrospective analysis of 10 years (1994 to 2003) of the Maryland hospital discharge database. Included in the analysis were patients with (1) International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure code 38.12 (endarterectomy of the vessels of the head and neck other than intracranial vessels) in the primary coding position but not in any secondary position, or (2) Diagnosis Code 433.00 to 433.91 (occlusion/stenosis, precerebral artery), or (3) the Diagnosis-Related Group 5 (extracranial vascular procedure). ICD codes representing preoperative conditions of the patients were identified and evaluated with stepwise regression modeling techniques for association with in-hospital deaths. Different regression models were evaluated and compared by discriminative power as measured by receiver operating characteristics (ROC) and goodness-of-fit to data as measured by r(2) and the Hosmer-Lemeshow statistic. A numeric index correlating with the risk of in-hospital death was constructed by rounding the correlation coefficients for the statistically significant variables from the logistic regression.

RESULTS

We identified 23,237 cases. The mean age of patients was 70.6 years, with 54.7% male patients. There were 125 in-hospital deaths (0.54%). Patient age and four patient medical conditions emerged with significant associations with in-hospital deaths after CEA, and their relationships can be summarized in a single diagnostic scale: 1 point for age > or =75, 2 points for atherosclerosis (ICD code 440), 3 points for cardiomyopathy (ICD code 425), 4 points for iron-deficiency anemia (ICD code 280), and 5 points for cerebral degeneration (ICD code 331). This scale has moderate discriminative power (ROC = 0.67). On average, each point increase on this scale is associated with a 1.58-times increase in mortality risk, with score of 6 on the scale carrying a mortality risk >5%.

CONCLUSIONS

This new 5-item scale, based on patient age and past medical history, correlates moderately with the rate of in-hospital death after CEA. This clinical index may serve to identify high-risk patients. Future improvements to this diagnostic scale should focus on the diagnostic values of additional laboratory and demographic data.

Is the rationale for carotid angioplasty and stenting in patients excluded from NASCET/ACAS or eligible for ARCHeR justified?

PURPOSE

To compare outcome after carotid endarterectomy (CEA) in patients who would have been excluded from the North American Symptomatic Carotid Endarterectomy Trial (NASCET) or the Asymptomatic Carotid Atherosclerosis Study (ACAS) or would have been eligible for Acculink for Revascularization of Carotids in High Risk Patients (ARCHeR), a current high-risk stent registry, with outcome in a similar cohort at low risk.

METHODS

Records of all CEAs performed at our institution from July 1993 to December 2000 were reviewed. Patients were assigned to groups either eligible or ineligible for NASCET and ACAS or ARCHeR, and criteria were stratified according to whether risk was defined by anatomic or medical problems or whether patients were ineligible according to nonmedical protocol exclusion criteria only.

RESULTS

Preoperative and postoperative data were sufficient to determine risk status according to various study criteria in 857 patients. Stroke or death within 30 days, the primary end point, occurred in 2.1% of patients. Rates were similar in patients excluded from (2.7%) or included in (1.6%) NASCET and ACAS and in patients eligible (3.1%) or ineligible (2.1%) for ARCHeR. Rates did not differ according to whether exclusion or inclusion was based on anatomic risk, medical risk, or protocol exclusion, although trends favored worse outcome in the ARCHeR medical risk subgroup. A higher rate of minor complications was found in the elderly; however, stroke and death rates were similar according to age, gender, repeat procedure, or the presence of contralateral occlusion.

CONCLUSIONS

No statistically or clinically significant differences were found in combined 30-day stroke or death rates after CEA in any group defined by previous surgical trials or current ongoing high-risk stent registry. While high-risk groups may exist, the premise that operative risk is higher in patients excluded from NASCET and ACAS or eligible for ARCHeR is not supported.