Hemodynamic assessment and surgical correction of kinking of the internal carotid artery

Although kinking of the internal carotid artery has been recognized for many years, the surgical significance of this lesion has remained controversial. The present study was designed to identify hemodynamic significance of kinking of the internal carotid artery using a positional testing technique with preoperative and postoperative noninvasive data that were correlated with intraoperative electromagnetic flow measurements to establish operative criteria. A fluid-filled oculoplethysmograph (OPG) was used to assess carotid artery flow in 26 patients with cerebral ischemic symptoms who had angiographic documentation of kinking of the internal carotid artery. OPG testing was done with the patient's head positioned first in the neutral, then in the right and left rotations, and then in extension-flexion positions. Sixteen patients underwent angioplasty. At operation electromagnetic flow measurements of the internal carotid artery were determined in these 16 patients with similar positional maneuvers. A reduction of flow from 30% to 80% was found on positional testing during operation in 14 of these 16, and all 14 of these patients also had abnormal preoperative OPG testing. After angioplasty, effects of position on internal carotid artery flow were eliminated, as proved by electromagnetic flowmeter measurements and by follow-up OPG studies in all 14 patients. The other two patients who had been subjected to surgical correction had no positional effects as documented by electromagnetic flowmeter testing. A high correlation between noninvasive data and operative flow measurements suggests that positional OPG testing is helpful in identifying hemodynamically significant kinking. Symptomatic patients with kinking of the internal carotid artery and abnormal OPG testing may be candidates for corrective surgery.