Arterial pressure and neurologic morbidity during carotid surgery under peridural anesthesia

In 163 carotid reconstructions under peridural anesthesia performed from 1988 to 1991, we routinely measured residual systemic and carotid artery pressure during clamping. Seventy-nine patients (48.5%) were asymptomatic and 84 (51.5%) had a history of neurologic manifestations in the form of transient ischemic attacks (28%) or stroke (13.5%). None of the patients died perioperatvely. Eight patients (4.9%) had strokes, with complete recovery in five. A shunt was placed in 22 patients (13.5%) because of neurologic evidence that carotid clamping was poorly tolerated. This study showed a distinct association between residual pressure in the internal carotid artery and systemic arterial pressure and intraoperative neurologic morbidity. Using a cutoff value of 35 mm Hg for residual pressure, the sensitivity was 77% and specificity 81%. Using a cutoff of 80 mm Hg, the sensitivity was 60% and specificity 86%. There was no correlation between mean systemic arterial pressure and residual carotid artery pressure. The use of a shunt was the only factor with predictive value for postoperative neurologic complications. These findings suggest that measurement of systemic arterial pressure and residual carotid artery pressure is useful during carotid surgery, but further study is needed before this information can be extrapolated to carotid surgery under general anesthesia.