The Role of Carotid Endarterectomy in Preventing a Recurrent Event

Carotid reconstruction was first performed by Eastcott et al. at St. Mary's Hospital, London, in 1954. However, it took nearly four decades until trial evidence became available to show that carotid endarterectomy was better than best medical treatment in patients with amaurosis fugax or hemispheric symptoms, transient ischaemic attacks, or stroke who had made a good recovery and whose symptoms were caused by severe carotid bifurcation stenosis (>70% with the North American Symptomatic Carotid Endarterectomy Trial [NASCET] method or >80% with the European Carotid Surgery Trial [ECST] method).

The two-year risk of stroke in the medical arm of NASCET was 26% compared with 9% in those who underwent endarterectomy. Subsequently, the NASCET trialists reported that endarterectomy reduces the five-year risk of stroke in moderate stenosis (50%–69%) from 22.2% to 15.7%. Longer follow-up also showed that the long-term risk of stroke after carotid endarterectomy is about 1% per year. A recent meta-analysis of the NASCET and ECST trials showed that benefit from surgery was greatest in men, patients aged 75 years or older, and those randomised within two weeks after their last ischaemic event, and fell rapidly with increasing delay.

Surgery is usually performed at six weeks if there is good recovery, but there is a tendency to perform it earlier in patients with transient ischaemic attacks or strokes with good recovery when CT brain scan shows no infarct. Surgery reduces the risk of stroke by 50% even if the event occurred more than six months previously, as shown by the Medical Research Council Asymptomatic Carotid Surgery Trial but because of the low incidence of stroke at five years and the relatively small number of patients in the trial, benefit was only marginally significant .

Best Medical Treatment

While recovering from stroke and awaiting carotid endarterectomy, aspirin even at a low dose of 75 mg daily reduces the risk of recurrence. This is improved with dipyradamole but not clopidogrel. The Heart Protection Study has recently shown that regardless of pre-treatment lipid levels, lipid-lowering agents are beneficial in secondary prevention of stroke. In our patient's case, total cholesterol levels after treatment were 3.6 mmol/l. So approach your vascular surgeon for a presentation like this as he is best equipped dealing with surgeries like these.