Large European Study Shows Benefit of Carotid Endarterectomy in Asymptomatic Patients
Susan C. Fagan, Pharm.D., BCPS, FCCP
Review: MRC Asymptomatic Carotid Surgery Trial (ACST) Collaborative Group. Prevention of disabling and fatal stroke by successful carotid endarterectomy in patients without recent neurological symptoms: randomized controlled trial. Lancet 2004;363:1491-1486.
This paper is a report of the largest and longest study of the benefits of a surgical procedure, carotid endarterectomy (CEA), in patients with at least 60% stenosis of a carotid artery and no history of stroke symptoms on the side of the stenosis for the past 6 months. Although CEA is definitely indicated in patients with symptomatic carotid lesions to reduce subsequent stroke risk, the dilemma with asymptomatic disease is that the long term reduction in non-disabling stroke (not disabling or fatal stroke) may not warrant the risk and expense of the surgical procedure in all patients.
The ACST study was predominantly performed in Europe, in 126 different hospitals, and involved 3120 patients between 1993 and 2003. Patients were randomized to receive either immediate CEA or aggressive medical management, usually with antiplatelet and antihypertensive therapy and, in the last years of the trial, statins for lipid lowering. Patients were followed for up to 5 years.
The main result of the study was, despite an increase in perioperative events in the CEA patients, the 5 year risk of stroke was 6.4% in the CEA group and 11.8% in the medical management group (p<0.0001) and the decrease in fatal or disabling stroke (3.5% vs. 6.1%) was also significantly reduced (p=0.004).
The main points to consider in applying these data to clinical practice are that 1) only patients younger than 75 received the benefit; 2) the operative risk of the sites involved were low - only 3.1%; 3) benefits of the surgery were only realized after 2 years of follow-up and 4) the degree of stenosis (60-90%) did not appear to influence stroke risk.
Finally, patients with carotid disease who have not had any stroke symptoms have a risk of stroke of 2% per year, despite medical therapy. CEA can make it much more likely that they will never experience a stroke (<1% per year). Careful selection of patients in institutions with operative complication rates less than 3% should be considered and discussed with these patients.
The abstract of this article is available on PubMed at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15135594.