Claes Forssell

Local Versus General Anaesthesia in Carotid Surgery. A Prospective, Randomised Study

A randomised, prospective study was performed to compare local (LA) and general anaesthesia (GA) in carotid surgery with special emphasis on complications and the need for intra-operative shunting. Fifty-six patients were randomised to LA and 55 to GA. Eight patients in the LA group required a GA for various reasons. During the same period 14 patients were not randomised. Seven perioperative neurological deficits occurred (5.6%), four in the LA group, two in the GA group, and one in the non-randomised group (NS). Selective shunting was used, in the Ga group according to stump pressure or in cases with a previous stroke and in the LA group according to the appearance of neurological symptoms. In the GA group 25 patients were shunted and in the LA group five patients (P less than 0.001) needed a shunt. If strict pressure criteria for shunting had been used in the LA patients, ten would have been shunted and three of the patients who developed symptoms during clamping would not have been shunted. During surgery the highest recorded systolic pressure was significantly higher in the LA group (210 mmHg versus 173 mmHg, P less than 0.001). LA for carotid endarterectomy is comparable with general anaesthesia regarding peroperative complications but produces significantly higher blood pressures than general anaesthesia. On the other hand it allows the possibility of neurologic monitoring of the patient and leads to significantly less use of an intra-operative shunt.

Long-term results after carotid artery surgery

This study presents the results from a follow-up after 414 carotid reconstructions performed on 352 patients during the years 1971-82. At the end of the follow-up period 267 patients were alive (75.8%) and 253 patients remained asymptomatic. The median follow-up time was 35 months (6 months-12 years). Patients with coronary artery disease (CAD) had a significantly lower survival than patients without signs of CAD. Coronary artery disease was significantly more frequent among patients with bilateral carotid lesions compared to patients with unilateral lesions. The actuarial stroke frequency, operative morbidity included, on the operated side was 2.5%/year. However, from 6 months postoperatively up to 8 years the stroke frequency was 1%/year. In the stroke frequencies all neurological deficits of more than 24 h duration are accounted for. Although there was a trend toward higher stroke rates among older patients there were no significant differences between age groups. Assuming a 10% stroke frequency during the first year after a TIA and a 6% annual stroke rate thereafter our results would cross even such a natural course curve at 18 months.

Pressure measurements as predictors for peroperative neurologic deficits in carotid surgery

Forty-eight carotid endarterectomies were performed using local anaesthesia. The need for an intra-operative shunt was estimated from the development of neurological symptoms during a test clamping period of 1 min. Two patients developed symptoms during test clamping but four others developed symptoms after 11 to 20 min of clamping. The internal carotid back pressure was 30 to 40 mmHg in all these cases and significantly lower than among patients not developing symptoms. A better prediction of the need for a shunt was developed from a combination of the stump index (SI = internal carotid artery stump pressure/systemic pressure x 100) and the carotid index (CI = carotid pressure before clamping/systemic pressure x 100). The combination of SI less than 30 and CI greater than 85 predicted in a highly significant way the need for a shunt during operation. With this method a group of patients with a higher risk of postoperative stroke may also be detected.

Risk factors in carotid artery surgery: An evaluation of 414 operations

Four hundred and fourteen carotid reconstructions performed on 352 patients during the years 1971-82 were analysed retrospectively. Fifty-eight percent of the patients were operated on because of hemispheric transient ischaemic attacks (TIA). Twenty-eight percent had suffered a stroke before surgery. The overall combined mortality and morbidity was 7.7%. The procedure mortality was 2.9% with a slightly higher mortality i.e. 5.9% in the stroke group although not significantly higher than among non-stroke patients with a mortality of 1.4%. Patients of more than 70-years had a significantly higher operative mortality (11.1%) than the rest of the patients (1.7%). Non-fatal strokes occurred in 20 patients (4.8%). No correlation was found with the degree of stenosis of the contralateral artery.