Original title: A clinical rule (sex, contralateral occlusion, age, and restenosis) to select patients for stenting versus carotid endarterectomy: Systematic review of observational studies with validation in randomized trials. Reference: Touzé E et al. Stroke. 2013;Epub ahead of print

Compared with carotid endarterectomy, angioplasty with stent is associated with an increased risk of pre- procedural stroke especially for patients with symptomatic stenosis. However, after passing the pre-procedure, the long-term risk is similar between the two methods suggesting that both procedures may be appropriate for different patients instead of competing.

First this work was a systematic review of observational studies (170 studies) that evaluated the risk factors to present events for both carotid endarterectomy and angioplasty. We found nine key factors: age, contralateral carotid occlusion, coronary heart disease, diabetes, sex, hypertension, peripheral arterial disease and finally type and side of the obstruction. We calculated the relative risks of each factor for stroke and death by identifying those with different effect as endarterectomy or angioplasty making a rule that was validated with randomized studies.

Contralateral occlusion and female gender are associated with an increased risk of stroke and carotid endarterectomy death but have not a significant influence in angioplasty. Those with restenosis caused by endarterectomy also shown at increased risk in a second surgery unlike angioplasty. Age was associated with an increased risk for both procedures but especially for angioplasty. Thus arose the four fundamental factors that were the basis for the rule named by researchers SCAR (the acronym for the 4 factors: Sex, Contralateral occlusion, Age, and Restenosis).

The relative risk of events with angioplasty versus surgery in patients negative SCAR was 0.93 (0.49 to 1.76, P = 0.83) as opposed to those with positive SCAR was 2.44 (1.71 to 3.48, P < 0.0001).

The rule was validated in 3 large randomized studies (EVA – 3S, SPACE, and ICSS) with a total of 3049 patients. Of the total, 694 patients (22.8 %) were classified as negative SCAR meaning had contralateral occlusion, restenosis, and female less than 75 years. In those with negative SCAR the absolute risk of any stroke or death was identical between surgery or angioplasty (5.6 % ) in contrast to patients with positive SCAR where angioplasty presented twice the events compared to surgery (8.4 % versus 3.5 % ). 

Conclusion: 

The rule SCAR is potentially useful to identify those patients in whom carotid angioplasty has a similar risk of stroke or death than endarterectomy. 

Editorial comment:

While this rule may be considered useful yet to be tested prospectively and possibly refined. The results of this study are contrary to those of a recent analysis of the CREST study where women had a higher risk of events with angioplasty than men (5.5 % versus 3.7 % ) 

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