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Biomedical subjects

D E Strandness

Publications and source records attributed to D E Strandness.

At least 199 records · Page 11Linked to original sources
PubMed1982

Evaluation of extracranial carotid artery disease by ultrasonic duplex scanning: a clinical perspective.

The development of noninvasive methods of extracranial carotid artery evaluation over the past decade has led to questions as to their usefulness in daily clinical practice. They have generally been proposed for use in screening asymptomatic patients with bruits or those about to undergo major operative procedures. Since patients with focal symptoms are considered candidates for arteriography, noninvasive tests in this situation may be redundant. However, as the accuracy of the imaging and pulsed Doppler methods has improved, it is appropriate to re-examine this question. Based upon our experience, it is our current feeling that initial screening using ultrasonic Duplex scanning does have a place in symptomatic patients and can be shown to be cost effective.

Angiography↗
PubMed1982

Pitfall of venous occlusion plethysmography.

The supposition that the lower limb expands uniformly in circumference during venous occlusion has been investigated. The 3 compartments of the calf were found to be expand to differing degrees depending on the volume of muscle within the compartment. The effect of this phenomenon on the measurement of venous outflow and capacitance using an overlapping strain gauge was assessed. When using an overlapping strain gauge, the anatomical site of overlap was found to alter the measured values of outflow and capacitance by as much as 50%. These errors do not arise with strain gauges designed to fit a small range of limb circumferences, so that no overlap occurs. The reproducibility of plethysmography may be enhanced by attention to the site and degree of overlap of gauges which are designed to fit all sizes of limb. Technicians performing venous occlusion plethysmography should be aware of these variations, so that the examination technique can be standardized.

Acute Disease↗
PubMed1982

Clinical carotid measurements: present and future state.

The most satisfactory methods of evaluating the carotid artery have included Doppler imaging and ultrasonic duplex scanning. It is now recognized that these techniques are most accurate when used in combination with spectral analysis to more objectively determine the flow patterns present across this important bifurcation. In the centers where there is the most experience in their use, the sensitivity of the methods approach 90% and are most accurate for detecting high-grade stenoses (greater than 50% diameter reduction). The most promising future applications include the use of computerized pattern recognition techniques to quantitatively separate patients with varying degrees of disease.

Journal Article↗
PubMed1981

Limb hemodynamics after aortic aneurysm resection.

Preoperative ankle/arm indices were determined in 104 lower extremities from 53 patients who underwent prosthetic graft placement for abdominal aortic aneurysms. Sixty-nine percent of the limbs (group 1) had a normal index; 31% of the limbs (group 2) had indices indicative of arterial occlusive disease. Early postoperative ankle/arm indices were determined in 87 limbs (57 in group 1 and 30 in group 2). Twelve group 1 limbs exhibited a postoperative decrease in the index. In group 2, four of the five decreases were seen when the distal anastomosis was placed above the inguinal ligament, while all 17 group 2 limbs in which the index increased had the distal anastomoses performed at the common femoral level. In 1.8% of the group 1 limbs and 6.7% of the group 2 limbs, a subsequent arterial procedure below the inguinal ligament was required. An additional 1.8% of group 1 limbs and 6.7% of group 2 limbs had undergone a distal arterial procedure prior to aneurysm resection.

Aged↗
PubMed1981

Importance of noninvasive ultrasonic-Doppler testing in the evaluation of patients with symptomatic carotid bruits.

An ultrasonic Duplex scanner was used to estimate the site and degree of extracranial arterial disease in two groups of patients with asymptomatic bruits. In the first 100 patients only the extent of disease was assessed with 37% of the sides with bruits having high-grade stenoses (greater than 50% diameter reduction) and one-half having lesions which narrowed the internal carotid artery by less than 50%. Seven percent were found to be normal. The remaining 6% had occlusion of the internal carotid artery. In a second group of 81 patients, the effect of the reported findings of the Duplex scan on patient management was reviewed. Only 13 patients underwent angiography and 11 of these were in patients with high-grade stenoses. Five carotid endarterectomies were performed and in each case, the patient had bilateral high-grade lesions. The implications of this diagnostic approach are discussed as well as the need for prospective studies of patients who present with an asymptomatic bruit.

Arteriosclerosis↗
PubMed1981

Spectral analysis of Doppler velocity patterns in normals and patients with carotid artery stenosis.

A computerized pattern recognition program was utilized to assess the predictive ability of various parameters obtained from the spectra of ultrasonic pulsed Doppler signals from the carotid arteries. The most accurate features selected by linear regression analysis were the natural log (ln) of the ratio of the mean velocity in the internal carotid artery compared to that in the common carotid artery, and the ln of the maximum velocity, the ln of the maximum frequency, and the square of the fractional broadening term, all of which were measured at peak systole in the internal carotid artery. Using the combination of the velocity ratio and the fractional broadening term, the average difference in the estimated percentage stenosis, as compared to that obtained by arteriography, was 12.8%.

Arteriosclerosis↗
PubMed1981

Ultrasonic duplex scanning for disease of the carotid artery.

The duplex ultrasonic scanner combines real-time B-mode imaging with a single-gate, variable-range pulsed Doppler. The detection and categorization of the severity of carotid artery atherosclerosis is achieved by performing spectral analysis of the pulsed Doppler velocity signal obtained from vessels of interest. Using this technique, 750 patients with suspected extracranial carotid artery disease were evaluated between January 1978 and January 1980. One hundred thirty-five of these 750 patients (18%) underwent cerebral arteriography performed with biplanar views of the carotid bifurcation. The degree of stenosis was measured independently in these patients and was available for comparison with the results of duplex scanning and spectral analysis. Duplex scanning correctly detected the presence of disease in 252 of 259 carotid arteries studied (97%). The extent of involvement varied from plaques that produced less than 10% diameter reduction to those that resulted in a total occlusion. The technique was less accurate with lesions that produced less than 10% diameter reduction.

Carotid Artery Diseases↗
PubMed1981

Noninvasive detection of internal carotid artery occlusion.

Flow in the common carotid artery is normally quasisteady with flow never approaching zero during diastole. With total occlusion of the internal carotid artery, flow in the common carotid assumes the pattern observed in the external carotid, which supplies a relatively high-resistance vascular bed. In 34 instances of total internal carotid obstruction, flow went to zero in diastole in 33 cases and also demonstrated flow reversal in 22. In addition, there was a significant reduction in peak systolic velocity when the low-resistance internal carotid was obstructed. These observations, which are simple to determine using an ultrasonic duplex scanner, are of value in suspecting total occlusion of the internal carotid artery, thus obviating the need for arteriography in some cases.

Arterial Occlusive Diseases↗
PubMed1981

Carotid arterial disease in patients undergoing coronary artery bypass operations.

The occurrence of stroke associated with coronary artery bypass operations is approximately 2%. In an attempt to reduce this incidence some centers have proposed carotid thromboendarterectomy for symptomatic and asymptomatic carotid arterial disease in patients undergoing a coronary artery bypass operation. To obtain a better understanding of the incidence of carotid occlusive disease in candidates for the coronary bypass operation and to evaluate the practical use of a noninvasive method to screen patients preoperatively, we evaluated 102 patients preoperatively with an ultrasonic Duplex scanner; 24 studies were requested on the basis of either previous neurologic problems or the presence of a bruit and 78 patients were evaluated as part of a study protocol. In the unrequested group 6% (5/78) of the patients had a stenosis of 50% diameter reduction or more. In the requested group 54% (13/24) had a stenosis of 50% diameter reduction or more. In the postoperative phase one stroke and one transient ischemic attack were noted among the unrequested group and none in those suspected of having carotid disease on clinical grounds. Neither affected patient had a high-grade stenosis. There is little evidence to support the contention that noninvasive screening of patients free of symptoms or signs of carotid disease prior to coronary artery bypass operation is a valuable method of screening for patients who will sustain a focal neurologic event.

Carotid Artery Diseases↗
PubMed1980

Natural history of above- and below-knee femoropopliteal grafts.

Postoperative physiologic data were reviewed in 74 patients with 85 femoropopliteal bypass grafts. Documented progression of atherosclerosis occurred in the aortoiliac segment in 18 limbs and in the popliteal and tibioperoneal vessels in 14 limbs, although aortoiliac disease was more often responsible for graft failure. Grafts with good postoperative runoff as determined by hemodynamic measurements had a statistically significant higher patency rate than those with poor runoff. Nearly half of the limbs with a progressive postoperative decline in the ankle-arm index ultimately had graft occlusion. Rapid progression of popliteal artery atherosclerosis distal to an above-knee graft was not a significant problem.

Aneurysm↗
PubMed1980

The physiology of venous claudication.

The hemodynamic features of venous claudication are presented in a patient with chronic occlusion of the iliac vein. Exercise results in a marked venous volume overload, particularly in the thigh, which leads to pain. The syndrome develops in patients with isolated iliac vein occlusion and patent, competent veins distal to the inguinal ligament.

Adult↗
PubMed1980

The influence of limb elevation, examination technique, and outflow system design on venous plethysmography.

The effect of limb elevation and the design of the thigh cuff outflow system on venous capacitance and venous outflow, as determined by strain gauge plethysmography, was reviewed in a group of normal limbs without evidence of deep venous thrombosis. We improved the reliability of plethysmography in evaluating venous outflow, particularly in the early period after cuff deflation, by using uniform leg elevation, large diameter outflow tubing, and single rather than simultaneous limb examinations. Based on this experience, an optimum technique of examination emphasizing precise limb elevation, sequential limb examination and proper design of the cuff outflow system was used to evaluate 21 patients with acute venous thrombosis. The results obtained were compared with previously reported results of strain gauge plethysmography in patients with acute venous thrombosis. This technique significantly reduced the incidence of false-positive results.

Extremities↗
PubMed1980

Correlation of arteriographic findings and symptoms in cerebrovascular disease.

The arteriograms of 109 patients with symptomatic cerebral ischemia were analyzed to determine the distribution of extracranial and intracranial vascular abnormalities. In the 66 patients with transient hemispheric or ocular ischemia, potentially embolic lesions were more common than hemodynamically significant lesions (84% versus 50%). In the 29 patients with fixed neurologic deficits, 25% had occlusion of the internal carotid artery on the appropriate side; ulcerated lesions were again more common in the remaining patent arteries than were hemodynamically significant lesions. The major difference between the transient group and the fixed group was the 29% incidence of intracerebral disease or anomaly in the transient group, with similar lesions in 90% of the group with fixed neurologic deficit. Symptoms of cerebral ischemia are more likely to be related to ulceration than to hemodynamically significant lesions. The risk of stroke seems greatest when there is also intracerebral siphon disease or anatomic anomaly of the circle of Willis.

Brain Ischemia↗
PubMed1980

Arteriosclerosis obliterans and associated risk factors in insulin-dependent and non-insulin-dependent diabetes.

The prevalence of arteriosclerosis obliterans (ASO) of the legs was determined by a battery of noninvasive tests in 141 insulin-dependent and 289 non-insulin-dependent diabetic subjects and in 64 other subjects. The prevalence of detectable ASO ranges from 18% in the younger IDDM group to 41% in the diet-treated NIDDM group. The prevalence of ASO increases 7.5% per decade, appears to increase 6.5% in the age-adjusted IDDM group, 9% in males, 19% in those with hypertension, and 12% in smokers. No consistently significant correlations with fasting glucose, glycosylated hemoglobin, or obesity were found. After accounting for the effect of smoking, the increased risk for ASO in males becomes nonsignificant.

Adolescent↗