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Abstract

The North American Symptomatic Carotid Endarterectomy Trial-NASCET AND Asymptomatic Carotid Atherosclerosis Study-ACAS:
Why are these studies important and noteworthy?
Carotid endarterectomy was first introduced in North America in 1954 and since then surgeons were performing this procedure for stroke prevention without much evidence of its efficacy. In 1988 the NASCET investigators set out to determine if CE was beneficial in patients with carotid stenosis and TIA or partial stroke, in other words symptomatic patients.
The same questions applied to patients who had no prior history of TIA or infarction. Therefore in 1987, the ACAS investigators designed a study to find out whether the addition of CE to aspirin plus risk factor modifications will affect the incidence of TIA or infarctions in patients with asymptomatic but haemodynamically significant carotid stenosis in at least one artery.
In the Pakistani perspective, it is important to know what kind of benefits can be expected from such an invasive procedure, and what should be the acceptable risk while undertaking them.
Who were the participants?
NASCET was conducted at 50 centers across USA and Canada for severe disease and patients with moderate disease were recruited from 106 centers. The selection of these centers was based on very stringent criteria. Each center had a rate of