A non-invasive Doppler velocity index that is specific for carotid artery stenosis is presented. The index is both non-dimensional (maximum/minimum velocity to remove within artery Doppler signal variability) and normalized (larger over smaller carotid maximum/minimum ratio to minimize between patient variability). Of 260 normal patients 94% had a maximum/minimum index between 1.00 and 1.25 and 97.5% had an index between 1.00 and 1.30. In 136 patients undergoing selective carotid arteriography the overall accuracy of the maximum/minimum index in predicting carotid stenosis was 85-87%. When 1.30 is taken as the maximum normal index value the test is 96.5% specific and 76% sensitive. The receiver operating characteristic curve indicates that patients with a maximum/minimum index greater than 1.4 have a 99% probability of significant carotid stenosis.

Blood Flow Velocity↗

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Collateral cerebral vascular resistance in patients with significant carotid stenosis.

This study tests, the hypothesis that asymptomatic patients with hemodynamically significant internal carotid artery stenosis have a lower ipsilateral collateral cerebral vascular resistance and hence greater blood flow than their symptomatic cohorts. We measured internal carotid artery blood flow and cerebral perfusion pressures intraoperatively prior to and after carotid endarterectomy in 35 symptomatic and 10 asymptomatic patients with hemodynamically significant internal carotid artery stenosis. When the stenosis produced 30% or greater reduction in blood flow the calculated nondimensional normalized ratio of collateral cerebral vascular resistance of ipsilateral hemisphere cerebral vascular resistance was 1.15 +/- 0.83 (mean +/- SD) for the 10 asymptomatic patients and 2.98 +/- 1.89 for the 35 symptomatic patients (p = 0.0044). For the subgroup of 22 patients with 50% or greater reduction in internal carotid artery blood flow the resistance ratios were 0.782 +/- 0.541 for the 5 asymptomatic patients and 3.21 +/- 2.26 for the 17 symptomatic patients (p = 0.029). These results suggest that asymptomatic patients with hemodynamically significant internal carotid artery stenoses have a lower collateral cerebral vascular resistance than their symptomatic cohorts. The low collateral resistance may provide an adequate collateral cerebral blood flow to prevent ischemia and symptoms.

Blood Pressure↗

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Prevention of early restenosis and thrombosis-occlusion after carotid endarterectomy by saphenous vein patch angioplasty.

The hypothesis that saphenous vein patch angioplasty protects against early postoperative restenosis and thrombosis-occlusion was tested by comparing the clinical outcome and carotid artery status of 100 carotid endarterectomies with and 100 without saphenous vein patch angioplasty performed by a single surgeon over a 30-month period. The patient population, selection, perioperative management, and the technical aspects of the operation, except for the vein patch, were essentially identical in both groups. Carotid artery status was assessed by direct continuous wave Doppler and Gee OPG at three to six months and again at one year postoperatively. There were two hospital deaths, both in the nonpatched group, one cardiac and the other neurologic due to internal carotid thrombosis. Two reversible neurological deficits due to thrombosis and one due to restenosis occurred in the non-patched group. Asymptomatic greater than 50% diameter restenosis occurred in four and asymptomatic occlusion in one non-patched carotids. There were no restenosis, no occlusions and no neurologic symptoms in the patched group. Morbidity, mortality, restenosis or thrombosis-occlusion occurred in 10/100 (10%) non-patched and 0/100 (0%) patched arteries (p less than 0.01 by Chi Square). Restenosis or thrombosis-occlusion occurred in 9/100 (9%) of non-patched and 0/100 (0%) patched arteries (p less than 0.01). These results support the use of saphenous vein patch angioplasty reconstruction of carotid endarterectomy to protect against early restenosis and thrombosis-occlusion.

Aged↗

PubMedDate not supplied

Restenosis after carotid endarterectomy in patients with paired vein and Dacron patch reconstruction.

This is an analysis of restenosis after bilateral carotid endarterectomy (CEA) with saphenous vein patch reconstruction on one side and Dacron patch reconstruction on the other. The possibility that differences in reconstruction geometry between vein and Dacron patched sides effected restenosis outcomes was evaluated as was the value of serial common carotid wall thickness measurements in predicting restenosis. Between 1990 and 1997, 33 bilateral CEA were performed within one year on 22 men and 11 women using a greater saphenous vein patch on one side and a knitted Dacron patch on the other. Interoperative post-CEA geometry was measured. Follow-up was by duplex scans that included wall thickness measurements in the endarterectomized common carotid bulb. Over a mean follow-up of 43 months 10 (30%) Dacron patched and one (3%) vein patched CEA developed > or = 25% restenosis (p = 0.001), seven (21%) Dacron patched and no vein patched CEA developed > or = 50% restenosis (p = 0.01) and four (12%) Dacron patched and no vein patched CEA developed > or = 70% restenosis (p = 0.11). The Kaplan-Meier cumulative > or = 25% restenosis rates for Dacron and vein patched CEA were 22% and 0% at 2 years and 41% and 5% at 5 years respectively (p = 0.002). The cumulative > or = 50% restenosis rates for Dacron and vein patched CEA were 16% and 0% at 2 years and 34% and 0% at 5 years respectively (p = 0.003). The cumulative > or = 70% restenosis rates for Dacron and vein patched CEA were 8% and 0% at 2 years and 20% and 0% at 5 years respectively (p = 0.02). For both patients with and without recurrent stenosis the mean within patient between sides differences of the diameters of the internal carotid, internal carotid bulb, common carotid bulb, and common carotid arteries and the lengths of the internal carotid and total patch segments were not significantly different and all were less than 5%. Common carotid bulb wall thickness measured at the time of identification of the nine unilateral Dacron patched CEA restenosis was 1.5 +/-0.5 mm compared to 1.4 +/-0.4 mm (m +/-1 SD) for the contralateral vein patched CEA (p = 0.45 by paired t test). Dacron patched CEA have a significantly higher incidence of mild, moderate and severe restenosis than do saphenous vein patched CEA independent of systemic risk factors. The within patient equality of Dacron and vein patched carotid reconstruction geometry in patients with unilateral restenosis indicates that patch material is the major local risk factor, not adverse hemodynamics produced by variance in geometry. Common carotid bulb wall thickness measurements after CEA are not predictors or indicators of recurrent stenosis.

Aged↗

PubMedDate not supplied

Management of the external carotid artery during routine carotid endarterectomy.

This study analyzes the results of carotid endarterectomy with a uniform technique of external carotid artery management. Aggressive blind instrument and eversion endarterectomy of the distal external carotid and its branches above the superior thyroid artery was performed during 211 standard carotid endarterectomies. This technique allows isolated external carotid artery repair if necessary after re-establishing carotid blood flow. Of these, 196 (92.9%) had normal intraoperative continuous wave Doppler ultrasonography in the external carotid. The 15 (7.1%) abnormal external carotid arteries underwent isolated completion endarterectomy with or without patch reconstruction followed by a normal Doppler study. All 15 had normal external carotid artery duplex ultrasonography 3 to 6 months after endarterectomy. However, 2 of the 196 (1.04%) intraoperative ultrasound normal external carotids had significant residual or recurrent stenosis (no occlusions) 3 to 6 months after endarterectomy for an early external carotid residual or restenosis rate of 0.95% (2/211). This was significantly less (p less than 0.05) than the 5.2% (11/211) 3- to 6-month incidence of residual or recurrent external carotid stenosis (6) and occlusion (5) in 211 carotid endarterectomies in which the external carotid artery was managed in an arbitrary manner. This study supports aggressive eversion endarterectomy of the external carotid artery during standard carotid endarterectomy with isolated repair when indicated.

Carotid Artery, External↗

PubMedDate not supplied

Cerebral revascularization by axillary-carotid bypass.

Revascularization for symptomatic proximal common carotid severe stenosis or occlusion frequently requires a bypass procedure. Subclavian-carotid bypass is probably the most frequently performed operation. In the past 5 years 13 patients underwent an alternative operation, axillary-carotid bypass, which may be technically easier than subclavian-carotid bypass and just as durable. The graft is placed under the clavicle, in an easily constructed tunnel not involving the true thoracic outlet, deep to the sternocleidomastoid muscle and internal jugular vein. Five distal anastomoses were made to the common carotid (2 greater saphenous vein, 2 Dacron and 1 Gortex grafts), 4 to the internal carotid (all vein) and 4 to the external carotid (all vein, 1 sequential with a end-side anastomosis to the ipsilateral vertebral). There were no perioperative deaths. One stroke occurred in a patient with a Dacron graft to the common carotid who also had a concomitant ipsilateral carotid endarterectomy. All grafts were open by Doppler exam at a mean follow-up of 2 1/2 years. Improved cerebral hemodynamics was confirmed in 11 patients by Gee oculoplethysmography. These early results support the use of the axillary artery as a donor for extracranial cerebral revascularization when the proximal common carotid is occluded or severely stenotic.

Aged↗

PubMedDate not supplied

Accuracy of ultrasound arteriography in symptomatic patients with carotid bruits and negative or equivocal noninvasive testing.

Twenty patients with cervical bruits and complete noninvasive workup--including Doppler ultrasonography, oculoplethysmography, and carotid phonoangiography--were further studied with ultrasound arteriography and contrast angiography. This unique group of patients who had cervical bruit and equivocal noninvasive testing results were found to have 14 abnormal angiograms. The Doppler ultrasound arteriography demonstrated 100% sensitivity and 66.7% specificity by patient, when compared to contrast angiography.

Aged↗