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Biomedical subjects

E F Bernstein

Publications and source records attributed to E F Bernstein.

At least 109 records · Page 6Linked to original sources
PubMed1982

Is carotid endarterectomy beneficial in prevention of recurrent stroke?

Of 456 consecutive carotid endarterectomies performed at the University of California, San Diego, 127 were in patients who had sustained a previous completed stroke and had recovered with minimal but permanent neurologic deficits (PNDs). Operative mortality for the entire series was 0.9%, but it was 3.1% for the stroke group. A postoperative PND was observed in 2.1% of patients without neurologic deficits but occurred in 3.9% of the patients after stroke. A 97% one-to-ten-year follow-up was obtained. The total early and late serious morbidity and mortality in this surgically treated series of patients after stroke was 24% at five years. We conclude that carotid endarterectomy for the prevention of recurrent stroke carries a high risk and may not be superior to nonoperative treatment.

Adult↗
PubMed1982

Should aortography be used routinely in the elective management of abdominal aortic aneurysm?

Until recently aortography was performed routinely for elective abdominal aortic aneurysm at our institution. A death resulting from this procedure prompted us to evaluate this policy by a retrospective study of 105 elective aneurysm patients. These studies identified 21 renal artery stenoses, 2 renal artery aneurysms, 2 cases of multiple renal arteries, 8 celiac stenoses, 6 superior mesenteric artery stenoses or occlusions, and a number of peripheral occlusive processes and associated iliac aneurysms. However, the impact of these findings on surgical management was limited to six renal artery reconstructions: one for reimplantation of a renal artery arising from the aneurysm, one for serious hypertension, and four in normotensive patients with severe arterial stenosis. No celiac or mesenteric reconstructions were undertaken, and no visceral complications ensured. In only one patient, the one with renal artery reimplantation, was the angiographic information unsuspected and significant for operative management. This did not appear to justify the risk and expense involved in routine preoperative aortography.

Aorta, Abdominal↗
PubMed1982

Current status of noninvasive tests in the diagnosis of peripheral arterial disease.

In this review of the current status of the vascular laboratory, the major emphasis has been upon those tests that have become well-established and documented, including resting pressure, pulse volume measurements, velocity studies, and three stress measurements--exercise ankle pressure, postocclusive reactive hyperemia, and the toe pulse reappearance time. Additional technology that may have application to peripheral arterial disease includes photoplethysmography, transcutaneous oxygen tension, laser-Doppler velocimetry, fluorescein angiography, infrared thermography, and transcutaneous electromagnetic flowmetry. These techniques, which are currently in development and experimental trial, were not discussed but are likely to provide significant additional information. The future role of the vascular diagnostic laboratory in the area of peripheral arterial occlusive disease appears clear. It has already become a standard resource of the community hospital and tertiary referral center. Its functions will become more and more generally accepted with time as newly graduating physicians who have been exposed to this technology enter the practice of medicine. It should permit obtaining an evaluation of all patients at the expert level, aid in the education of all physicians concerned with peripheral arterial disease, and play an important part in guaranteeing a higher level of patient care than has heretofore been available.

Arterial Occlusive Diseases↗
PubMed1982

Transcutaneous PO2 measurements in health and peripheral arterial occlusive disease.

Transcutaneous oxygen tensions (tcPO2) of the lower extremity were investigated in 24 control subjects and in 69 patients with various degrees of peripheral arterial occlusive disease. With a modified Clark-type oxygen electrode, tcPO2 was monitored from the right subclavicular region (position 1), upper calf (position 2), and dorsum of the foot (position 3). The tcPO2 was significantly lower in patients when compared to control subjects. The reproducibility of the method was determined from double determinations of the tcPO2 (position 2) in control subjects. The comparison of tcPO2 value between the right and left lower extremity showed no significant differences. The tcPO2 of the foot or leg showed an increase, when positioning the limb below the phlebostatic level. The response of the tcPO2 after transient arterial occlusion (4 minutes) was significantly delayed in patients compared to control subjects. Finally, preliminary results of 35 patients in whom amputations had been performed suggest that tcPO2 measurement may become a useful prognosticator for the determination of the optimal amputation level.

Adult↗
PubMed1981

The effect of sensing site on the limb segmental blood pressure determination.

The effect of the sensing site on upper-thigh blood pressure readings was studied. We used a multisensing mercury strain gauge (MSG) plethysmographic method and Doppler ultrasound to monitor the upper-thigh blood pressure from the posterior tibial artery and compared the results with those from the popliteal artery. Upper-thigh pressures were measured in 30 limbs of 15 normal subjects and in 60 limbs of 35 patients with multilevel peripheral arterial occlusive disease. Upper-thigh pressures sensed from a thigh MSG placed just distally to the pressure cuff and monitored by the popliteal artery Doppler probe were significantly higher than the upper-thigh pressure readings obtained from an MSG placed on the calf or toe and monitored by a posterior tibial artery Doppler probe in patients with multilevel arterial lesions. In the control group, no significant pressure differences were found. The importance of placing the sensor (MSG or Doppler probe) close to the pressure cuff is critical to obtain accurate thigh pressures in patients with multilevel arterial occlusive disease. Otherwise, erroneous diagnoses, such as nonexistent aortiliac or common femoral artery stenosis, may be made.

Adolescent↗
PubMed1981

Valve competence following experimental venous valve autotransplantation.

In canine experiments, venous patency and valvular competence were evaluated following transposition of a valve-containing vein segment, with an without a distal arteriovenous (AV) fistula. The effects of distal fistula size on valvular function were also examined. Autogenous valve-containing venous segment grafts were placed in the femoral position. With no adjuncts, 90% of the grafts showed either occlusion, severe extrinsic narrowing, or intraluminal filling defects on early venograms, although 75% of valves were eventually competent at death. Veins that had undergone thrombosis and recanalization were routinely incompetent. With a distal AV fistula, all veins remained patent and 86% demonstrated valve competence. With both an AV fistula and dextran 40, all veins remained patent and all valves were component. Separately, graded size of AV fistulas did not result in loss of valve competence. Following venous segment transposition, continuous venous patency appears necessary for eventual valvular function, and this is enhanced by both a distal AV fistula and dextran.

Animals↗
PubMed1981

Toe pulse reappearance time in prediction of aortofemoral bypass success.

The noninvasive vascular laboratory has a great potential to influence patient care if it can offer predictive information, which significantly adds to the clinical and angiographic assessment. To evaluate such preoperative data, 80 patients (143 symptomatic limbs) who underwent aortofemoral bypass were re-evaluated one to seven years following surgery. Preoperative vascular laboratory data (segmental pressure profile, quantitative Doppler velocity indices, postocclusive reactive hyperemia and toe pulse reappearance time [TPRT], following a four-minute cuff occlusion), angiography and clinical status were compared with the postoperative symptomatic result. Overall, 27% of the limbs were asymptomatic, 56% of the limbs markedly improved, 7% of the limbs remained unchanged or worse, and 10% of the patients died. Computer analyses of all preoperative data yielded several significant predictive indices, of which the most sensitive was the TPRT. With a TPRT of 0-10 seconds, all patients became either asymptomatic (63%) or markedly improved (37%). With increases in the TPRT, the results worsened, in stepwise fashion. Combinations of pressure and reactive hyperemic indices also permitted successful predictions in patients with multilevel disease. Such preoperative information can play a significant role in identifying the relative risks and benefits of surgery, and may significantly influence the decision for surgery in borderline situations.

Aorta, Abdominal↗
PubMed1981

Digital ischemia: angiographic differentiation of embolism from primary arterial disease.

Embolic disease is often overlooked as a cause of digital ischemia. Unilateral symptoms, in particular, should suggest the possibility of emboli arising from the subclavian or more distal upper extremity vessels. Emboli may originate in the subclavian artery as the result of atherosclerosis at its origin or arterial injury secondary to thoracic outlet compression. Arteriography can be useful in the identification of upper extremity emboli and their source, and should include studies of the aortic arch, proximal subclavian artery, and digital arteries. Retrograde subclavian injections may be required to adequately demonstrate the origin of the subclavian artery. Magnification technique is often essential in differentiating small digital artery emboli from primary arterial diseases, such as Buerger disease or scleroderma.

Adult↗
PubMed1981

Acute physiologic effects of arteriovenous anastomosis and fistula in revascularizing the ischemic canine hind limb.

In a severe, diffuse arterial occlusion model of canine hind-limb ischemia, both distal arteriovenous fistula (AVF) and arteriovenous end-to-side anastomosis (AVA) were evaluated as potential methods of revascularization. AVA reversed or minimized both hemodynamic and metabolic indices of ischemia; AVF did not. After AVA segmental blood pressures at the thigh returned to normal, and those at the calf returned to 0.8 from an ischemic level of 0. Both postocclusion toe pulse reappearance times and the toe pulse volumes partially returned toward normal. IN addition, gastrocnemium intramuscular Po2 returned from an ischemic level of 5.3 to 45.5 mm Hg, compared to a control normal of 47.6 mm Hg. Muscle surface pH returned to 7.40 from the ischemic level of 7.06. AVA appears to offer an approach to the treatment of severe, diffuse arterial disease that would utilize the distal venous tree to transport blood to the capillaries for the support of adequate tissue nutrition.

Animals↗
PubMed1981

Thigh pressure artifacts with noninvasive techniques in an experimental model.

In an experimental canine model of isolated and tandem arterial stenoses, noninvasive thigh and calf pressure measurements were evaluated against direct intra-arterial pressures. Under control circumstances, proximal iliac arterial stenosis, and high superficial femoral artery stenosis, the noninvasive measurements were highly accurate. However, when stenoses were created distal to the high pressure cuff, a significant error in the thigh pressure measurement was observed, with an underestimation of thigh pressure and subsequent false implication of a proximal lesion. Two tandem distal lesions produced a significantly more severe thigh measurement artifact. Further, the noninvasive system was incapable of detecting a moderately severe profunda stenosis, although stenoses of the iliac and femoral system were detected in a routine, accurate, and sensitive fashion.

Animals↗
PubMed1980

Prognosis of asymptomatic ulcerating carotid lesions.

To determine the proper approach to asymptomatic carotid bifurcation ulcerated plaque (UP), 79 patients with 91 asymptomatic UPs were identified angiographically, and a 96% follow-up was obtained with a mean duration of three years. The cumulative stroke rate by life-table analysis was 1% at seven years. Sixty-three UPs in 55 patients were classified as small, and of these patients, transient ischemic attacks (TIAs) that were appropriate to the lesion developed in three and stroke in one (7% cumulative symptom rate). Twenty-four UPs in 21 patients were classified as large, and a TIA developed in one patient (9%), but no strokes were observed in this group. The cumulative mortality was 17% at three years and 52% at seven years. Life-table curves of several subgroups were compared and showed no significant differences in either stroke rate or mortality between any of these groups. On the basis of these data, and particularly the seven-year stroke rate of 1%, prophylactic carotid endarterectomy is not justified for asymptomatic carotid bifurcation ulcerations.

Actuarial Analysis↗
PubMed1980

Ultrasonic imaging of the carotid arterial system.

The ability of a B-mode, real-time, high frequency ultrasonic imager to diagnose carotid arterial disease was evaluated in 81 carotid arteries. The imager was relatively sensitive in detecting the presence of significant stenosis but was relatively insensitive in its ability to quantitate the degree of stenosis. The imager was unable to detect the presence of ulcerations. The oculoplethysmograph had a greater sensitivity, specificity and accuracy than the ultrasonic imager in diagnosing carotid arterial stenosis in the same group of patients. Ultrasonic imaging appears to be useful as a screening test of cerebrovascular disease when used in combination with the oculoplethysmographic test.

Arterial Occlusive Diseases↗
PubMed1980

Hemodynamic response to exercise in the unanesthetized calf with pulseless arterial flow.

In a chronic unanesthetized calf model with a centrifugal pump inserted from left ventricle to aorta, calves were trained to perform treadmill exercise and undergo hemodynamic measurements. Resting hemodynamic changes with pulseless pumping included increases in cardiac output, aortic pressure, and heart rate, with some decrease in systemic vascular assistance. Treadmill exercise was associated with further increases in cardiac output and heart rate, which progressively increased during the 10 days of observation, with little change in mean aortic pressure. Pump autoregulation responded to the decreased systemic vascular resistance associated with exercise by increasing pump output about 15%, at constant pump rotatory speed. These experiments add further evidence regarding the ability of a centrifugal left ventricular assistance system to support the failing heart and to permit moderate degrees of exercise in the intact unanesthetized calf.

Animals↗
PubMed1979

Quantitative transcutaneous arterial velocity measurements with Doppler flowmeters.

A controlled in vitro and in vivo comparative evaluation of four Doppler ultrasonic blood velocimeters was performed to evaluate their ability to measure fluid velocity throughout a wide range of flow rates and velocity profiles, during both steady and pulsatile flow. The instruments tested were the Versatone Bidirectional Doppler M-9, the Sonicaid BV380, the Parks 806 B, and the Delalande DUD 400. All instruments responded linearly to velocities of from 5 to 70 cm/s, and were accurate to within 5% through a wide range of in vitro changes in velocity, pulse frequency, and cross-sectional velocity profile. Quantitative velocity measurements and their derivatives are an inexpensive, simple, and useful tool in the evaluation conditions of patients with peripheral vascular disease, and widespread clinical trials of their value are appropriate at this time.

Animals↗
PubMed1979

Revascularization of the ischemic canine hindlimb by arteriovenous reversal.

Arteriovenous reversal (AVR) for revascularization of ischemic tissues has previously failed to meet theoretical, experimental, and clinical expectations despite recurrent trials. The efficacy of a new staged approach to AVR was tested against a canine ischemic limb preparation in which global ligation of ipsilateral collaterals inevitably led to limb gangrene. In 12 animals the complications of direct, single-stage end-to-end femoral AVR, inevitably accompanied by the development of extreme edema, were demonstrated. However, when the ischemic preparation was accompanied by a staged AVR, in which an initial end-artery-to-side-vein arteriovenous fistula was converted 1 week later to AVR by ligation of the central venous limb, 20 of 20 animals survived, and 19 of 20 were ambulatory long-term survivors with only mild edema. Serial angiograms at 1 week, 1 month, and 4 months demonstrated patency rates of 100, 84, and 63%, respectively. Histologic examination of animals electively killed from 4 to 24 months showed normal skeletal muscle histology, venous intimal thickening, and mild edema. In the acutely ischemic canine hind limb, a staged AVR can provide both viability and function with only mild edema formation.

Animals↗