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Biomedical subjects

E F Bernstein

Publications and source records attributed to E F Bernstein.

At least 91 records · Page 5Linked to original sources
PubMed1988

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.

Aged↗
PubMed1988

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.

Aged↗
PubMed1987

Evaluation of a new classification of cerebrovascular disease: CHAT.

A new scheme that classifies cerebrovascular disease on the basis of current and prior clinical symptoms, arteriographic findings, and target organ abnormalities has been evaluated. The scheme proved to be easy to learn and to use. Its utility was demonstrated by the previously unreported distinctions that became apparent when various patient subsets were analyzed according to the CHAT classification. These included an improved probability of stroke-free survival in patients operated on for brief strokes (transient ischemic attack) as opposed to temporary strokes (reversible ischemic neurologic deficit), and similarly improved survival probability in patients operated on for amaurosis fugax in comparison to those with carotid territory hemispheric transient ischemic attacks. The impact of multiple arterial lesions and positive computerized tomography scan findings appeared to be minimal with respect to both late stroke and survival in our preliminary observations. The simplicity and utility of the CHAT scheme make it a useful method to evaluate and report clinical experience with cerebrovascular disease.

Carotid Arteries↗
PubMed1987

The value of power frequency spectrum analysis in the identification of aortoiliac artery disease.

Prediction and localization of significant proximal occlusive disease in the lower extremities, whether in isolation or in combination with significant distal disease, still represent major problems to the noninvasive vascular laboratory. Power frequency spectrum analysis (PFSA) was done on continuous-wave Doppler signals in the common femoral artery of 86 limbs in 50 patients before and after postocclusive reactive hyperemia testing in an effort to differentiate hemodynamically significant from insignificant proximal occlusive disease, whether in isolation or in combination with hemodynamically significant distal disease. Limbs were assigned to four different categories according to their angiographic findings. With the use of a bandwidth at 50% peak amplitude (f50%) of 2000 Hz as the cut-off point between a positive and a negative examination, the test was 93% sensitive, 90% specific, and 92% accurate in distinguishing hemodynamically significant proximal lesions from hemodynamically insignificant lesions, regardless of distal disease. In addition, there exists a small group with significant disease at or close to the site of Doppler sampling, which produces f50% values of more than 3000 Hz. Diagnosis in this subgroup was much like that in carotid disorders. Finally, the predictive accuracy of standard noninvasive Doppler/segmental pressure measurement was compared with results of PFSA. In most patients, standard measurements were comparable; however, in the subgroup with hemodynamically significant proximal and distal disease, the PFSA technique accurately predicted hemodynamically significant proximal diseases in 93% of patients, where combined pressure/Doppler testing had an accuracy of only 61%. In all, spectrum analysis of common femoral artery velocity signals can greatly aid in determining the presence or absence of significant proximal disease in all situations.

Aorta, Abdominal↗
PubMed1987

Late results after carotid endarterectomy for amaurosis fugax.

Amaurosis fugax is considered an ocular transient ischemic attack with an ominous prognosis. One hundred twenty-eight patients with amaurosis fugax as the presenting symptom underwent carotid endarterectomy at the University of California, San Diego (UCSD) and Scripps Clinic between 1970 and 1985 with one death (0.8%) and one postoperative permanent stroke (0.8%). Subsequently, these patients were followed up for 6 to 160 months (mean 45.3 months). Only two subsequent late strokes were documented (at 2 and 5 years after operation). These results were significantly better (p less than 0.01) by life-table analysis than the late stroke rate after carotid endarterectomy performed to treat anterior motor transient ischemic attacks at both UCSD and Scripps Clinic, as well as the reported late follow-up for all transient ischemic attacks after carotid endarterectomy in the literature (1.8% per year, 17 publications, 1980 operations). Thus amaurosis fugax appears to be a particularly favorable indication for carotid endarterectomy. Left untreated, this event carries a high risk of stroke; after carotid endarterectomy, which has a low operative risk, there is a very low postoperative stroke rate (two strokes in 448 patient-years of follow-up).

Actuarial Analysis↗
PubMed1986

Continuous-wave versus range-gated pulsed Doppler power frequency spectrum analysis in the detection of carotid arterial occlusive disease.

Two types of ultrasonic Doppler velocity metering devices currently used in the detection of extracranial carotid artery disease, the continuous-wave (CW) and the range-gated pulsed (RP) Doppler systems, were compared in the present study. Power frequency spectrum analysis (PFSA) was performed on 130 carotid arterial bifurcations with a CW Doppler and 81 carotid arteries with an RP Doppler system. All results were compared with angiographic findings. The frequency bandwidth at 50% peak power (f50%), a quantitative index for defining spectral broadening, detected stenoses equal to or greater than 50% diameter reduction with 93% sensitivity, 92% specificity, and 92% accuracy with the CW system. With the RP Doppler, the same degree of stenosis was identified with 94% sensitivity, 93% specificity, and 93% accuracy. Compared with angiographic classification into 0-24%, 25-49%, and 50-99% diameter reduction categories, CW Doppler PFSA and an 85% overall accuracy, and the RP Doppler overall accuracy was 86%. CW Doppler also correctly identified 15 of 16 internal carotid artery (ICA) occlusions; 8 of 8 ICA occlusions were correctly identified with the RP Doppler. Thus, both techniques detected carotid artery disease with comparable results. For research and ease of operation, an RP Doppler system with a variable sampling volume appears to be most desirable. However, a standard CW system is superior if utility and cost-effectiveness are of prime importance.

Arterial Occlusive Diseases↗
PubMed1986

A comparison of B-mode real-time imaging and arteriography in the intraoperative assessment of carotid endarterectomy.

In this study we compare intraoperative B-mode imaging with arteriography in the same patient for intraoperative assessment after carotid endarterectomy. Since April 1983, 158 patients have been studied with both techniques. After a routine intraoperative arteriogram, the vessel was examined in multiple planes with a B-mode imager, and the impression of the operating surgeon was recorded before review of the arteriogram. Thirteen studies were unsatisfactory because the design of the probe did not allow examination of the high carotid bifurcation. Twelve patients had significant abnormalities (8.3%) in the internal carotid artery. Results were false negative in three intraoperative arteriograms (2.1%) and five B-mode imaging studies (3.4%). In each of the 12 cases the vessel was reopened and the abnormality confirmed and corrected. Fifty-seven patients had abnormalities (37%) in the external carotid artery. Results were false negative in eight arteriograms (5.3%) and in 12 B-mode imaging studies (7.9%). Fourteen of the 57 patients with abnormalities of the external carotid artery underwent repeat operation to correct the technical problem. Although not conclusive, the incidence of postoperative neurologic deficit as well as that of recurrent carotid stenosis seems decreased since both modalities for intraoperative assessment were used. The data suggest that neither intraoperative angiography nor B-mode imaging, when used alone, accurately detects all postoperative abnormalities. The results also suggest that a heightened sensitivity to technical details may improve both early and late postoperative morbidity.

Carotid Arteries↗
PubMed1985

Oxygen inhalation--induced transcutaneous PO2 changes as a predictor of amputation level.

Noninvasive transcutaneous PO2 (TcpO2) determinations have been developed to study peripheral arterial occlusive disease. To evaluate this technique as a predictor of amputation outcome, a blind, prospective study of 101 patients undergoing 119 amputations (23 above-knee [AK], 57 below-knee [BK], and 39 forefoot) was performed. TcpO2 measurements were obtained from the dorsum of the foot and 10 cm distal to the patella, both prior to and 10 minutes after inhalation of 100% oxygen. On the basis of preliminary results, initial TcpO2 values greater than 10 mm Hg or an increase greater than 10 mm Hg after oxygen inhalation were considered to predict a successful outcome, whereas failure was predicted when the initial TcpO2 value was less than 10 mm Hg and the increase after oxygen inhalation did not exceed the 10 mm Hg level. In the BK amputation group the test was 95% sensitive, 100% specific, and 95% accurate. Retrospective utilization of the above criteria in patients who had undergone both oxygen inhalation testing and AK amputation suggested that 9 of 17 limbs (53%) might have undergone a more distal BK amputation successfully. These results document the effectiveness of an initial TcpO2 determination coupled with the response to 100% oxygen inhalation as an excellent predictor of the outcome of lower extremity amputations.

Adult↗
PubMed1985

The contribution of spectral analysis to the diagnosis of carotid artery disease.

Pulsed and continuous-wave Doppler examinations with spectral analysis were performed on 258 carotid arteries in 220 patients and compared with multiplane contrast angiography. Each artery was examined for stenosis and assigned to one of four groups: normal to 19%, 20% to 49%, 50% to 99%, and occlusion. The incidence of disease was 70%. Diagnostic sensitivity with all noninvasive techniques varied from 76% to 90% depending on the degree of stenosis, with an overall accuracy rate of 86%. In an attempt to evaluate the diagnostic contribution of spectral analysis, stenosis classification by peak frequency alone was compared with that of the full laboratory profile, including spectral analysis. In the 147 carotid arteries in which such data were available, diagnostic sensitivity was improved with spectral analysis by 8% to 29% depending on the degree of stenosis. Detection of occlusions was unchanged. The major contribution of spectral analysis was in detecting non-flow-limiting stenoses of 20% to 49%. Spectral analysis added little to the diagnostic ability of peak frequency to detect lesions with greater than 50% stenosis. Spectral analysis of either pulsed Doppler or continuous-wave Doppler signals is an accurate noninvasive method for evaluating carotid bifurcation disease, which particularly improves the detection of non-flow-limiting stenoses.

Arterial Occlusive Diseases↗
PubMed1984

Posterior communicating artery visualization in predicting results of carotid endarterectomy for vertebrobasilar insufficiency.

Retrospectively, 51 patients who related two or more signs or symptoms of vertebrobasilar insufficiency and possessed concomitant carotid arterial disease were identified. The patient population was separated into two groups based on the presence or absence of an angiographically visualized posterior communicating artery during selective carotid artery injection. All patients had undergone unilateral or staged bilateral carotid endarterectomy. Comparison of postoperative clinical outcome with intracerebral angiographic findings exhibited statistically significant improvement in favor of those patients with at least one visualized posterior communicating artery. There was a greater likelihood of severe vertebral artery stenosis in those patients whose symptoms were not relieved by carotid endarterectomy.

Aged↗
PubMed1984

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 angio-plasty 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.

Arterial Occlusive Diseases↗
PubMed1984

Abdominal aortic aneurysm in high-risk patients. Outcome of selective management based on size and expansion rate.

Low mortality rates for elective surgical treatment of abdominal aortic aneurysms justify an aggressive approach in most patients. However, in high-risk patients with small aneurysms and no symptoms, the decision to operate remains a delicate balance of risk and benefit. Our observations include 99 high-risk patients with asymptomatic abdominal aortic aneurysms initially measuring 3 to 6 cm in the largest transverse diameter, who have been followed 1 to 9 years (average 2.4 years) with serial echographic measurements. Elective operations were performed for aneurysmal enlargement greater than 6 cm or symptom development. An additional 11 patients with aneurysms initially greater than 6 cm, whose initial evaluation did not result in elective surgery, were also followed. Serial data documented a mean expansion rate of 0.4 cm/year for aneurysms smaller than 6 cm. Forty-one of these 99 high-risk patients with small aneurysms eventually underwent an elective resection with two deaths (4.9%). Thirty-four patients (34%) died from causes unrelated to their unoperated aneurysms, and 21 patients (21%) are alive without symptoms. Three of the 99 patients suffered aneurysm rupture and emergency operation with two deaths. Thus, of the 99 high-risk patients with small aneurysms, four have died of elective aneurysm surgery or rupture (4%). A protocol of re-echo (or computerized tomography) examination at 3-month intervals appears to define which of these high-risk patients require elective aneurysm surgery, and has limited rupture to less than 5%. Improved criteria may emerge from recent advances in high-resolution computerized tomography.

Aorta, Abdominal↗
PubMed1984

Inferior vena cava bypass: experimental evaluation of externally supported grafts and initial clinical application.

Inferior vena caval obstruction is an unusual but important clinical problem for which adequate treatment previously has not been available. Recently, a polytetrafluoroethylene (PTFE) graft with external rigid spiral supports was developed that appeared particularly applicable to the venous system. In 18 dogs a 15 cm length of Impraflex was placed from the proximal right common iliac vein to the inferior vena cava (IVC) at the level of the renal veins after IVC and right iliac vein interruption. End-to-end and end-to-side iliac vein anastomoses were alternated, with and without distal femoral arteriovenous (AV) fistulas (AVFs). At 2 months, with a distal AV fistula, 11 of 12 (92%) grafts were patent, angiograms demonstrated no evidence of intraluminal clot, and there was no hind limb edema. Following AVF ligation 2 months after graft insertion, 10 grafts remained patent, but five developed some intraluminal thrombus and one of them progressed to complete occlusion. Four months after fistula ligation (6 months after graft insertion) 9 of 12 grafts (75%) remained patent. All six grafts without distal AVF were occluded within 1 week. This procedure was performed on one severely symptomatic patient who had IVC occlusion, and currently the patient shows marked improvement. Thus IVC bypass is possible when an externally supported PTFE prosthesis is complemented by a temporary AVF.

Adult↗
PubMed1983

Natural history of asymptomatic ulcerative plaques of the carotid bifurcation.

In 79 patients with 91 asymptomatic ulcerating lesions of the carotid bifurcation who were followed an average of 54 months, there were two strokes, one of which was preceded by a warning transient ischemic attack. These data suggest that asymptomatic type A and type B carotid ulcerating lesions do not carry a significant early risk of stroke and do not warrant prophylactic carotid endarterectomy. However, the effect of antiplatelet drugs and anticoagulation in enhancing the development of subintimal hemorrhagic lesions remains uncertain. Further data with serial follow-up, preferably by noninvasive means, will be necessary to define the evolution of asymptomatic ulcerating carotid plaques and eventually permit identification of those lesions that have significant stroke potential.

Angiography↗
PubMed1983

Life expectancy and late stroke following carotid endarterectomy.

A review of the UCSD experience with 456 consecutive carotid endarterectomy procedures confirms the acceptably low operative mortality and morbidity associated with this operation. Immediate complications were not different when routine or selective shunting was performed, but the patients with a low internal carotid artery back pressure had higher operative complication rates. The coexistence of atherosclerosis in other parts of the body severe-enough to warrant surgery for them was not associated with either higher early or late carotid surgery complication rates. Following both coronary bypass and carotid procedures, the late mortality was decreased, and the late incidence of stroke was particularly low in comparison to the remainder of the patient group. Late follow-up emphasized the high continuing attrition rate from all causes in these patients. Late strokes continued to occur, particularly in patients with prior strokes and severe preoperative bilateral carotid disease. The late course of patients with posterior circulation transient ischemic attacks treated by carotid endarterectomy was quite similar to that of patients treated for anterior circulation transient ischemia attacks (TIAs). Newer postoperative screening procedures may decrease the incidence of late postoperative stroke by identifying recurrent carotid stenosis while it is still in the asymptomatic stage.

Aged↗
PubMed1983

Selective streptokinase infusion: clinical and laboratory correlates.

Selective intra-arterial infusions of streptokinase (SK) were made in 50 arteries of 45 patients with a variety of acute thromboembolic conditions. The most common regimen was 5,000 units of SK/hour for 24 to 48 hours with a simultaneous heparin infusion of 250 to 500 units/hour. Significant lysis occurred in 80% of cases, with 74% of the patients benefiting clinically. Minor bleeding, usually from puncture sites, occurred in 30% of the patients. Major hemorrhages, requiring transfusion or surgery, developed in four patients (8%). No hemorrhagic strokes or fatalities were directly attributable to SK infusion. Coagulation parameters were determined before infusion, 4 and 24 hours after infusion, and every 24 hours thereafter. Significant alterations of coagulation parameters developed promptly, but were not very useful in predicting either clinical response or hemorrhage. Selective intra-arterial infusion of SK is a moderately effective and safe therapeutic technique in acute peripheral arterial thromboembolic disease. A comparison with prior reports suggests that selective low-dose infusion provides a moderate gain in benefit-risk ratio over systemic infusion.

Angiography↗