Shirley M. Otis

P300 latency reflects the degree of cognitive decline in dementing illness.

An auditory discrimination paradigm was employed to elicit the P3 component of the event-related brain potential (ERP) from 39 demented patients (mean age = 71 years). Component latency was longer in patients who were diagnosed as having primary degenerative dementia and other cognitive impairment disorders compared to age-matched controls. Neurologist ratings of cognitive impairment were significantly correlated with P3 latency values, although no differences in mean latency were obtained between the various categories of dementia. ERP measurement techniques and the interpretation of P3 latency as in index of dementing illness are discussed.

Propagation of deep venous thrombosis identified by duplex ultrasonography

To investigate the efficacy of anticoagulation in preventing continuing thrombosis, we prospectively evaluated 24 patients with acute deep venous thrombosis using duplex ultrasonography. All patients were hospitalized with conclusive ultrasonic evidence of deep venous thrombosis identified in one of four levels: I, calf only; II, calf-popliteal; III, calf-popliteal-femoral; or IV, calf-popliteal-femoral-iliac. Duplex scans were obtained on admission and on three subsequent occasions during therapy. Progression of thrombosis was defined as advancement of thrombus to the more proximal venous level. Demographic data, symptoms, risk factors for deep venous thrombosis, physical findings, anticoagulation regimens, and hematologic variables were ascertained. Adequacy of anticoagulation was defined as elevation of baseline activated partial thromboplastin time by 150%. Nine patients (38%) had progression of thrombosis, and 15 (62%) had stable or improving duplex scans. Progression occurred as follows: I----II (2), I----III (2), II----III (1), and III----IV (4). Of the demographic and clinical variables examined, only smoking correlated with progression of thrombus (p = 0.04). Average heparin dose in the stable group was 1214 +/- 294 units/hr and 1122 +/- 248 units/hr in the group that progressed (p = 0.8): activated partial thromboplastin time was 45.6 +/- 7 seconds in the stable group and 49.8 +/- 9 seconds in the progression group (p = 0.7). Nine patients in the stable group had consistently adequate anticoagulation, whereas six did not; six in the progression group were consistently anticoagulated, and three were not. Two patients (one with stable thrombus and one with progressive thrombus) suffered nonfatal pulmonary emboli. Clot progression as determined by duplex scanning did not predict acute complications of deep venous thrombosis.

Effect of internal carotid artery occlusion on intracranial hemodynamics. Transcranial Doppler evaluation and clinical correlation.

Neurologic deficits that occur simultaneously with or subsequent to internal carotid artery occlusion may be influenced by the adequacy of the intracerebral collateral circulation. Transcranial Doppler ultrasonography was used to evaluate mean middle cerebral artery blood velocity and blood flow in major collateral arteries in 78 patients, including 39 patients with 40 internal carotid artery occlusions and 39 control patients with less severe extracranial cerebrovascular disease, matched for age and sex distribution. Middle cerebral artery blood velocity was 38.9 +/- 17.9 cm/sec ipsilateral to an occlusion, 50.9 +/- 18.3 cm/sec contralateral to an occlusion (p less than 0.01), and 56.8 +/- 14.4 cm/sec in the controls (p less than 0.01). Pulsatility index ipsilateral to an occlusion (0.86 +/- 0.32) was reduced compared with contralateral and control pulsatility indexes (1.05 +/- 0.33 and 1.03 +/- 0.18) respectively; p less than 0.05). Major intracerebral collateral arteries were detectable in 94.9% of occlusion patients and in 53.8% of controls (p less than 0.01). A posterior communicating artery was demonstrated ipsilateral to an occlusion in 80.0% of the patients and contralateral to an occlusion in 39.5% (p less than 0.01). An ipsilateral posterior communicating artery was identified in all 10 asymptomatic occlusions and in 75.8% of the symptomatic ones. Pulsatility index was 1.02 +/- 0.34 for asymptomatic occlusions and 0.76 +/- 0.30 for symptomatic occlusions (p less than 0.01). Transcranial Doppler ultrasonography permits noninvasive quantification of the cerebral hemodynamic consequences of internal carotid artery occlusion and direct evaluation of the collateral blood supply, which can be correlated with symptomatology.

Recurrent carotid artery stenosis following endarterectomy

Spectral analysis was used to examine 257 carotid arteries in 227 patients who had undergone carotid endarterectomy at 1, 3, 6, and 12 months after surgery and annually thereafter. Routine intraoperative completion angiography ensured that the operations were technically satisfactory. Postoperative restenoses were identified in 38 patients (15%). In 23 arteries (9%), the restenosis exceeded a 50% diameter reduction while in 15 arteries (6%) the stenosis was less than 50% of the diameter. Restenosis developed in 24/96 women (25%) and 14/161 men (9%). Twenty-nine (70%) stenotic lesions occurred within 12 months. In three patients early lesions regressed. Reoperation with patch angioplasty was required in six patients. When the 219 carotid arteries that remained widely patent were compared to the 38 that restenosed, no differences were noted for age, diabetes mellitus, hypertension, smoking, or degree of preoperative stenosis. Early stenotic lesions appear to be due to myointimal hyperplasia, which is probably platelet mediated. The predominant female sex distribution may be explained by differences in platelet responsiveness in men and women.

Noninvasive assessment of cerebral collateral blood supply through the ophthalmic artery.

We assessed the potential of 2-MHz pulsed-wave transorbital Doppler ultrasonography to delineate the role of the ophthalmic artery as a source of collateral cerebral blood supply by comparing oculopneumoplethysmography, transorbital Doppler ultrasonography, periorbital continuous-wave Doppler ultrasonography, and transcranial Doppler ultrasonography in 25 patients with unilateral internal carotid artery occlusion and five controls with 10 normal internal carotid arteries. Systolic ophthalmic artery blood velocity was reduced ipsilateral to an internal carotid artery occlusion (38.2 +/- 10.2 cm/sec) compared with the contralateral and control velocities (46.0 +/- 10.3 and 47.5 +/- 6.8 cm/sec, respectively; p less than 0.05). Ophthalmic systolic pressure measured by oculopneumoplethysmography was 94.7 +/- 13.2 mm Hg ipsilateral to an internal carotid artery occlusion compared with 108.4 +/- 15.3 mm Hg on the contralateral side (p less than 0.01). Transorbital and periorbital Doppler ultrasonography detected reversed ophthalmic artery blood flow ipsilateral to an internal carotid artery occlusion in 44.0% and 40.0% of the patients, respectively. Systolic middle cerebral artery blood velocity was 55.2 +/- 22.3 cm/sec ipsilateral to an internal carotid artery occlusion compared with 79.4 +/- 23.5 cm/sec on the contralateral side (p less than 0.05) and 101.2 +/- 18.9 cm/sec in the controls (p less than 0.05). Reversed ophthalmic artery blood flow was associated with a low middle cerebral artery blood velocity and lack of major intracerebral collaterals. Transorbital Doppler ultrasonography permits noninvasive evaluation of the ophthalmic artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of cerebral collateral pathways during carotid endarterectomy.

Before surgery, we evaluated major intracranial collateral pathways using transcranial Doppler ultrasonography (TCD) in 50 patients who then underwent carotid endarterectomy with concurrent multimodality cerebral monitoring. Patients were grouped with respect to collateral pathways demonstrated preoperatively by TCD: Group 1, good collateralization with an anterior and/or posterior communicating artery ipsilateral to the operative carotid lesion (29 patients, 58%); Group 2, collateral pathways present but impeded by other proximal stenoses (nine patients, 18%); and Group 3, no collateralization identified (nine patients, 18%). Three patients (6%) could not be classified. TCD identified major collateral pathways with a sensitivity of 89% and a specificity of 80% when compared with arteriography. During carotid endarterectomy mean middle cerebral artery velocity, pulsatility index, and stump pressure were higher and the decrease in middle cerebral artery velocity with extracranial carotid artery cross clamping was significantly less among Group 1 patients than among Group 2 and 3 patients (p less than 0.05 for both groups). Group 1 patients required fewer intraoperative carotid artery shunts and developed fewer ischemic electroencephalographic abnormalities than did patients in Groups 2 and 3 (p less than 0.05 for both groups). TCD assessment of cerebral collateralization helps predict hemodynamic consequences of cross clamping during carotid endarterectomy.

Transcranial Doppler in the management of extracranial cerebrovascular disease: implications in diagnosis and monitoring

Transcranial Doppler (TCD) insonation permits quantitative noninvasive evaluation of intracerebral arterial velocity. With the use of a 2 MHz Doppler through a transtemporal approach, middle cerebral artery blood velocity (MCA-V, centimeters per second) and major collaterals were measured in 96 patients, including 15 normal control subjects, 66 patients with extracranial cerebrovascular disease (ECCVD), and 15 patients with other medical problems without ECCVD. MCA-V was higher in control subjects (62.7 ± 15.1) than in patients with ECCVD (45.0 ± 16.3, p < 0.05). There was a significant inverse correlation between MCA-V and the degree of internal carotid artery stenosis present by duplex examination. Twenty-three patients monitored during carotid endarterectomy had a mean MCA-V under anesthesia of 37.0 ± 16.9, which decreased to 22.4 ± 14.8 during cross-clamping (p < 0.01). MCA-V during cross-clamping correlated directly with stump pressure (R = 0.87) and was higher when major collaterals were identified before operation by TCD than when none were seen (31.7 ± 9.5 vs. 8.8 ± 8.5, p < 0.01). Shunt function was verified in all 11 patients shunted. Electroencephalographic changes occurred in four patients with an MCA-V of 14.7 ± 8.5 compared with an average of 24.1 ± 15.5 for patients with normal electroencephalograms. MCA-V increased from 46.6 ± 21.2 before operation to 61.0 ± 22.4 after carotid endarterectomy (p < 0.05). TCD can quantitate intracerebral blood flow in specific vessels, collateralization, the degree of cerebral ischemia caused by ECCVD, intraoperative changes in MCA-V that correlate with stump pressure and the electroencephalogram, shunt function, and the increases in cerebral blood flow resulting from carotid surgery. It is a new and important tool. (J VASC SURG 1988;7:223-31.)

Screening for abdominal aortic aneurysms during lower extremity arterial evaluation in the vascular laboratory

PURPOSE The purpose of this study was to evaluate the cost-effectiveness of screening for abdominal aortic aneurysms (AAA) during noninvasive lower extremity arterial examination in the vascular laboratory. METHODS Over 30 months we screened 531 patients who underwent lower extremity arterial evaluations in the vascular laboratory. The patients had fasted overnight, and, after the regular noninvasive lower extremity arterial examination, the abdominal aorta was screened with B-mode ultrasonography. RESULTS The aorta was adequately visualized in 475 patients (89%). Mean aortic diameter was 19.6 +/- 4.1 mm at the juxtarenal level and 18.8 +/- 7.2 mm in the lower infrarenal aorta. The aortic diameter was larger in men (p < 0.001) and in smokers (p < 0.001). AAA (diameter greater than 3.0 cm) were identified in 32 patients (6.0% of the 531 patients screened), and 15 of the aneurysms were equal to or larger than 4.0 cm. The best predictors for AAA by logistic regression analysis were male sex (p < 0.005), advanced age (greater than 65 years, p < 0.01), and a history of smoking (p < 0.01). The prevalence of AAA was 6.7% (32/475) in the population in whom the aorta was visualized and 15.2% (19/125) in male smokers over 65 years of age. Aneurysms of 4.0 cm or greater were identified in 3.2% of the entire population screened and 8.8% of male smokers over age 65. Limited aortic scanning prolonged the vascular laboratory examination by an average of 5 minutes. Thus detection of one aneurysm required 83 minutes of scanning time for the whole population studied and 36 minutes of scanning of male smokers over age 65, at a cost of

Acute effects of smoking on human cerebral blood flow: a transcranial Doppler ultrasonography study.

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Measurement of Anterior and Posterior Circulation Flow Contributions to Cerebral Blood Flow: An Ultrasound-derived Volumetric Flow Analysis

553 per aneurysm identified. CONCLUSION Screening for AAA during lower extremity arterial evaluation in the vascular laboratory addresses a high-risk population, is cost-effective, and should be considered an appropriate and valuable addition to the examination protocol.