Leading article Br. J. Surg. 1991, Vol. 78, October. 1153-1155
Current status of carotid endarterectomy The brain receives its blood supply through four arteries, the two internal carotid and the two vertebral arteries. Occlusion of one of these vessels only affects cerebral blood flow if the circle of Willis is deficient. Consequently, the simplistic hope that relieving a partial obstruction of one carotid artery will improve cerebral blood flow and reduce the risk of stroke has never had a sound physiological basis. However, when it became clear in the 1950s' that many strokes were caused by emboli derived from atheromatous disease at the bifurcation of the carotid artery, surgeons argued strongly that removal of this disease would reduce the risk of stroke. This was not just a pipe-dream, for surgical removal of disease at the carotid bifurcation is a practical possibility because it is usually limited to the first 2-3 cm of the internal carotid artery, with healthy vessels above and below. The logic of the argument seemed undeniable, and consequently the number of carotid endarterectomies (CEs) performed throughout the world steadily increased. By the mid 1980s CE was the most common arterial operation performed in the USA'. This boom was encouraged by the publication of many individual uncontrolled series of operations which showed that the procedure could be performed with very low rates of mortality and morbidity, and further expanded by the introduction of CE for asymptomatic disease. It was this latter expansion of the indications for CE that made many surgeons, and still more neurologists, review the evidence justifying its use. In spite of the logic, and in spite of the many published personal series, the evidence was found to be inadequate and certainly not good enough to justify 100000 operations each year. Consequently, in the mid 1980s the clinical trialists moved in. Four large multicentre trials were started, two to study symptomatic disease and two to study asymptomatic disease. The first two have been reported, and to the vascular surgeons' relief and barely concealed delight show that they had been right from the beginning.
Description of trials MRC European Carotid Surgery Trial (ECSlJ3. This was designed to assess the value of CE in patients who, after having a carotid territory, non-disabling ischaemic stroke, transient ischaemic attack (TIA) or retinal infarct, are found to have a stenotic lesion in the relevant (ipsilateral) carotid artery. North American Symptomatic Carotid Endarterectomy Trial (NASCET,14. This was designed to answer the question: does CE, despite the perioperative risk of stroke or death from any cause, reduce the overall risk of fatal and non-fatal ipsilateral carotid stroke among symptomatic patients with high grade carotid stenosis (7Cb99 per cent)? Asymptomatic Carotid Atherosclerosis Study (ACA5J5. This was designed to determine whether CE plus aspirin and risk factor modification in patients without symptoms reduce the incidence of carotid-derived TIAs or cerebral infarction when compared against aspirin and risk factor modification alone. Veterans' Administration Asymptomatic Carotid Stenosis Trial6. This was designed to answer the question: does CE plus aspirin in patients without symptoms reduce the incidence of TIAs or stroke when compared with aspirin alone?
Present status of trials MRC European Trial of Symptomatic Disease3. The results of the first analysis were reported in May 1991. They show that CE confers a significant benefit in patients with severe (70-90 per cent) stenosis. Of 2518 randomized patients, 778 were in the severe category and 455 were treated surgically; 7.5 per cent had a stroke or died within 30 days of surgery, but during the next 3 years only another 2.8 per cent had strokes, compared to 16.8 per cent of the control patients, a sixfold reduction
0007-1323/91/10115343
C
1991 Butterworth-Heinemann Ltd
1153
Leading article
(P
Current status of carotid endarterectomy The brain receives its blood supply through four arteries, the two internal carotid and the two vertebral arteries. Occlusion of one of these vessels only affects cerebral blood flow if the circle of Willis is deficient. Consequently, the simplistic hope that relieving a partial obstruction of one carotid artery will improve cerebral blood flow and reduce the risk of stroke has never had a sound physiological basis. However, when it became clear in the 1950s' that many strokes were caused by emboli derived from atheromatous disease at the bifurcation of the carotid artery, surgeons argued strongly that removal of this disease would reduce the risk of stroke. This was not just a pipe-dream, for surgical removal of disease at the carotid bifurcation is a practical possibility because it is usually limited to the first 2-3 cm of the internal carotid artery, with healthy vessels above and below. The logic of the argument seemed undeniable, and consequently the number of carotid endarterectomies (CEs) performed throughout the world steadily increased. By the mid 1980s CE was the most common arterial operation performed in the USA'. This boom was encouraged by the publication of many individual uncontrolled series of operations which showed that the procedure could be performed with very low rates of mortality and morbidity, and further expanded by the introduction of CE for asymptomatic disease. It was this latter expansion of the indications for CE that made many surgeons, and still more neurologists, review the evidence justifying its use. In spite of the logic, and in spite of the many published personal series, the evidence was found to be inadequate and certainly not good enough to justify 100000 operations each year. Consequently, in the mid 1980s the clinical trialists moved in. Four large multicentre trials were started, two to study symptomatic disease and two to study asymptomatic disease. The first two have been reported, and to the vascular surgeons' relief and barely concealed delight show that they had been right from the beginning.
Description of trials MRC European Carotid Surgery Trial (ECSlJ3. This was designed to assess the value of CE in patients who, after having a carotid territory, non-disabling ischaemic stroke, transient ischaemic attack (TIA) or retinal infarct, are found to have a stenotic lesion in the relevant (ipsilateral) carotid artery. North American Symptomatic Carotid Endarterectomy Trial (NASCET,14. This was designed to answer the question: does CE, despite the perioperative risk of stroke or death from any cause, reduce the overall risk of fatal and non-fatal ipsilateral carotid stroke among symptomatic patients with high grade carotid stenosis (7Cb99 per cent)? Asymptomatic Carotid Atherosclerosis Study (ACA5J5. This was designed to determine whether CE plus aspirin and risk factor modification in patients without symptoms reduce the incidence of carotid-derived TIAs or cerebral infarction when compared against aspirin and risk factor modification alone. Veterans' Administration Asymptomatic Carotid Stenosis Trial6. This was designed to answer the question: does CE plus aspirin in patients without symptoms reduce the incidence of TIAs or stroke when compared with aspirin alone?
Present status of trials MRC European Trial of Symptomatic Disease3. The results of the first analysis were reported in May 1991. They show that CE confers a significant benefit in patients with severe (70-90 per cent) stenosis. Of 2518 randomized patients, 778 were in the severe category and 455 were treated surgically; 7.5 per cent had a stroke or died within 30 days of surgery, but during the next 3 years only another 2.8 per cent had strokes, compared to 16.8 per cent of the control patients, a sixfold reduction
0007-1323/91/10115343
C
1991 Butterworth-Heinemann Ltd
1153
Leading article
(P
![[Current status of carotid endarterectomy].](/assets/img/hold.png)
