Validation of a Risk Scoring System to Predict Life Expectancy after CEA in Patient with Asymptomatic Carotid Artery Stenosis

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Development and validation of a score to predict life expectancy after carotid endarterectomy in asymptomatic patients

OBJECTIVE: Recent improvement of best medical treatment for carotid stenosis has sparked a debate on the role of surgery-identification of patients who may benefit from carotid endarterectomy (CEA) is crucial to avoid overtreatment. An expected 5-year postoperative survival is one of the main selection criteria. The aim of this study was the development of a score for predicting survival of asymptomatic patients after CEA. METHODS: Our score was derived from a retrospective analysis of 648 consecutive asymptomatic patients from a single hospital. External validation of the score was then performed on a second cohort of 334 asymptomatic patients from two different hospitals in the same area. Factors associated with reduced postoperative survival within the derivation cohort (DC) were identified and tested for statistical significance. Each selected factor was assigned a score proportional to its \u3b2 coefficient: 1 point for chronic obstructive pulmonary disease, diabetes mellitus, coronary artery disease, and lack of statin treatment; 4 points for age 70 to 79 years and creatinine concentration 651.5 mg/dL; 8 points for age 6580 years and dialysis. The DC was divided into four groups based on individual scores: group 1, 0 to 3 points; group 2, 4 to 7 points; group 3, 8 to 11 points; and group 4, 6512 points. Group-specific survival curves were calculated. The validation cohort (VC) was stratified according to the score. Survival of each of the four risk groups within the VC was compared with its analogue from the DC. RESULTS: Median follow-up of the DC and VC was, respectively, 56 and 65 months. Intercohort comparison of 5-year survival was 84.7% \ub1 1.7% vs 85.2% \ub1 2% (P = .41). Group-specific 5-year survival within the DC was 97% \ub1 1.5% (group 1), 88.4% \ub1 2.2% (group 2), 69.6% \ub1 4.7% (group 3), and 48.1% \ub1 13.5% (group 4; P < .0001). Five-year survival within the VC was 95.5% \ub1 2% (group 1), 89.5% \ub1 2.7% (group 2), 65% \ub1 6.1% (group 3), and 44.8% \ub1 14.1% (group 4; P < .0001). Intercohort comparison of group-specific survival curves showed close similarity throughout the groups. CONCLUSIONS: Our score is a simple clinical tool that allows a quick and reliable prediction of survival in asymptomatic patients who are candidates for CEA. This selective approach is crucial to avoid unnecessary surgery on patients who are less likely to survive long enough to experience the benefits of this preventive procedure

10-year stroke prevention after successful carotid endarterectomy for asymptomatic stenosis (ACST-1); a multicentre randomised trial

BACKGROUND: If carotid artery narrowing remains asymptomatic (ie, has caused no recent stroke or other neurological symptoms), successful carotid endarterectomy (CEA) reduces stroke incidence for some years. We assessed the long-term effects of successful CEA. METHODS: Between 1993 and 2003, 3120 asymptomatic patients from 126 centres in 30 countries were allocated equally, by blinded minimised randomisation, to immediate CEA (median delay 1 month, IQR 0·3-2·5) or to indefinite deferral of any carotid procedure, and were followed up until death or for a median among survivors of 9 years (IQR 6-11). The primary outcomes were perioperative mortality and morbidity (death or stroke within 30 days) and non-perioperative stroke. Kaplan-Meier percentages and logrank p values are from intention-to-treat analyses. This study is registered, number ISRCTN26156392. FINDINGS: 1560 patients were allocated immediate CEA versus 1560 allocated deferral of any carotid procedure. The proportions operated on while still asymptomatic were 89·7% versus 4·8% at 1 year (and 92·1%vs 16·5% at 5 years). Perioperative risk of stroke or death within 30 days was 3·0% (95% CI 2·4-3·9; 26 non-disabling strokes plus 34 disabling or fatal perioperative events in 1979 CEAs). Excluding perioperative events and non-stroke mortality, stroke risks (immediate vs deferred CEA) were 4·1% versus 10·0% at 5 years (gain 5·9%, 95% CI 4·0-7·8) and 10·8% versus 16·9% at 10 years (gain 6·1%, 2·7-9·4); ratio of stroke incidence rates 0·54, 95% CI 0·43-0·68, p<0·0001. 62 versus 104 had a disabling or fatal stroke, and 37 versus 84 others had a non-disabling stroke. Combining perioperative events and strokes, net risks were 6·9% versus 10·9% at 5 years (gain 4·1%, 2·0-6·2) and 13·4% versus 17·9% at 10 years (gain 4·6%, 1·2-7·9). Medication was similar in both groups; throughout the study, most were on antithrombotic and antihypertensive therapy. Net benefits were significant both for those on lipid-lowering therapy and for those not, and both for men and for women up to 75 years of age at entry (although not for older patients). INTERPRETATION: Successful CEA for asymptomatic patients younger than 75 years of age reduces 10-year stroke risks. Half this reduction is in disabling or fatal strokes. Net benefit in future patients will depend on their risks from unoperated carotid lesions (which will be reduced by medication), on future surgical risks (which might differ from those in trials), and on whether life expectancy exceeds 10 years. FUNDING: UK Medical Research Council, BUPA Foundation, Stroke Association