BALLOON TEST OCCLUSION OF THE INTERNAL CAROTID-ARTERY WITH HYPOTENSIVE CHALLENGE

PURPOSE: To evaluate the usefulness of provocative testing with hypote nsive challenge during balloon test occlusion of the internal carotid artery before carotid sacrifice and to correlate tolerance of balloon test occlusion with clinical outcome after carotid artery sacrifice. M ETHODS: Forty-seven consecutive cases of balloon test occlusions perfo rmed at our institution during the past 4 years were retrospectively r eviewed, Occlusion was performed under normotensive conditions with di stal perfusion of heparinized saline for 20 minutes, or until a defici t was perceived. If 20 minutes of normotension was tolerated, hypotens ion was induced to two thirds of mean arterial pressure for 20 minutes , or until a deficit was perceived. RESULTS: Of 47 patients, 4 (9%) ha d deficits at normotension. Of the remaining 43 patients, 9 (21%) had deficits at hypotension. One patient with a positive hypotensive test occlusion underwent carotid artery sacrifice after extracranial-intrac ranial bypass without sequelae. In one of the 19 patients who clinical ly tolerated test occlusion with hypotension and had carotid sacrifice (surgical ligation of the intracranial carotid artery), a mild emboli c stroke developed, probably from the giant carotid wall aneurysm. Thi s patient fully recovered; MR imaging showed mild changes consistent w ith emboli distal to the aneurysm. Symptomatic complications were note d in 2 (4%) patients, and asymptomatic arterial dissections were noted in 3 (6%) patients. CONCLUSION: Balloon test occlusion with hypotensi ve challenge is safe, economical, and greatly increases the sensitivit y of balloon test occlusion. The predictive;value of a negative test i s high. However, to determine the test's specificity compared with qua ntitative imaging, controlled trials will be necessary.