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Biomedical subjects

D E Strandness

Publications and source records attributed to D E Strandness.

342 records · Page 19Linked to original sources
PubMedDate not supplied

Ultrasonic demonstration of external and internal carotid patency with common carotid occlusion: a preliminary report.

Non-invasive ultrasonic imaging of the carotid bifurcation by duplex scanning and ultrasonic arteriography combined with pulsed Doppler spectrum analysis demonstrated patency of the external and internal carotid arteries distal to a common carotid occlusion in 3 patients. Common carotid occlusion is not invariably associated with thrombosis of the ipsilateral internal carotid artery. Identification of internal carotid patency by the use of ultrasonic techniques will permit surgical treatment in selected cases.

Aged↗
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Quantitative carotid phonoangiography.

One hundred and sixteen carotid artery bruits were assessed using quantitative phonoangiography (spectral bruit analysis - SBA). This technique uses the averaged break frequency of the bruit to calculate the diameter of he residual lumen at the site of stenosis. Biplanar contrast arteriography was performed on 43 (37%) of the sides. All 116 sides were also evaluated with an ultrasonic Duplex scanner. Ten (8.6%) bruits could not be analyzed by the SBA, leaving 106 sides in which the residual lumen diameter could be estimated. The diameter of the vessel at the site of stenosis estimated by SBA and arteriography were compared and found to agree within 1 mm of each other in 85% of patients. A linear relationship was demonstrated between absolute lumen diameter and percent stenosis as measured from the arteriograms, but we were unable to correlate the absolute diameter of hte residual lumen as assessed by arteriography or SBA with the assessment of the degree of the stenosis derived from spectral analysis of the pulsed Doppler signal. The significance of these findings is discussed with relevance to the clinical application of spectral bruit analysis.

Auscultation↗
PubMedDate not supplied

Computer based classification of carotid arterial disease: a prospective assessment.

A minicomputer based pattern recognition method has been used to prospectively classify the category of disease involvement of 105 carotid arteries. The system utilized spectral patterns obtained from a combined B-mode/pulsed Doppler unit. All decisions are based upon comparison of an unknown, averaged waveform with a series of vessels with known severity of disease. The variability in the computer decision as compared to arteriography is discussed.

Adult↗
PubMedDate not supplied

Observer variability in evaluating extracranial carotid artery stenosis.

One hundred twenty eight cervical carotid arteriograms were twice viewed by three readers for the evaluation of atherosclerotic disease at the carotid bifurcation. Stenoses were estimated using calipers to the nearest 5% and lesions were qualitatively characterized as smooth, irregular, or ulcerated. The intraobserver correlation coefficient between estimates of percent stenosis was .94 overall and .98 for the internal carotid artery. The average intraobserver variability in estimating percent stenosis was 5.23% for all vessels and 6.04% with a standard deviation of 8.09% for the internal carotid artery. The intraobserver percent agreement at a fixed stenosis is defined as the percent of the time one reader on two readings would read at least the fixed percent stenosis among cases that might be read as having the fixed percent stenosis. The intraobserver percent agreement rate for the internal carotid artery was 95.9% at greater than 0% stenosis, 90.4% for 50% or greater stenosis, and 96.8% for 100% stenosis (total occlusion). The interobserver correlation coefficient between readers was .92 overall and .97 for the internal carotid artery. The absolute difference in percent stenosis between readers was 7.21% for all vessels and 8.64% for the internal carotid artery with a standard deviation of 9.5%. The interobserver agreement rate for the internal carotid artery at greater than 0% stenosis was 93.0%, 85.4% for 50% or greater stenosis and 96.8% at 100% stenosis. The addition of oblique views had no statistical effect on estimates of percent stenosis but increased the frequency with which irregularity and ulceration were diagnosed in the internal carotid artery.

Carotid Arteries↗
PubMedDate not supplied

The natural history of carotid arterial disease in asymptomatic patients with cervical bruits.

A prospective study was initiated in January 1980 to follow with Duplex scanning a consecutive series of 167 asymptomatic patients with cervical bruits. Patients were seen at six month intervals for the first year and yearly thereafter. Based on previously validated criteria, disease at the carotid bifurcation was classified into 6 categories: Normal, 1-15% diameter reduction, 16-49%, 50-79%, 80-99%, and occlusion. Patients were evaluated to assess: the occurrence of new neurological symptoms, the stability of the lesions at the carotid bifurcation, and the possible role of risk indicators on disease changes. During follow-up, ten patients became symptomatic (6 with TIA's and 4 with stroke). The development of symptoms was accompanied by disease progression in 8 patients. By life table analysis, the annual rate occurrence of symptoms was 4%. The mean annual rate of disease progression to a greater than 50% stenosis was 8%. When progression in all categories was considered, 60% of the sides showed some disease aggravation. The presence of or progression to a greater than 80% stenosis was highly correlated (p = 0.00001) with either the development of a total occlusion of the internal carotid artery or new symptoms. The major risk factors associated with disease progression were cigarette smoking, diabetes mellitus, and age. Those patients under 65 years of age were most likely to show progression. Despite high rates of disease progression, this study further supports the contention that it is prudent to follow a conservative course in the management of asymptomatic patients presenting with a cervical bruit.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Operative versus nonoperative management of asymptomatic high-grade internal carotid artery stenosis: improved results with endarterectomy.

In a 4-year period, 129 asymptomatic high-grade (80-99%) internal carotid artery stenoses were identified in 115 patients. Because we previously demonstrated a strong relation between degree of carotid stenosis and subsequent development of ipsilateral related events (stroke, transient ischemic attack, and carotid occlusion), we changed our previous policy and began to offer carotid endarterectomy to good surgical risk patients referred to us with asymptomatic high-grade carotid stenosis. A total of 56 carotid endarterectomies were performed while 73 lesions were followed nonoperatively. Operated and nonoperated groups were similar with regard to age, prevalence of hypertension, cardiac disease, diabetes, and aspirin use. Life table analysis to 24 months revealed a higher rate of stroke (19 vs. 4%, p = 0.08), transient focal neurologic deficits (28 vs. 5%, p = 0.008), and carotid occlusion (29 vs. 0%, p = 0.003) in the nonoperated group. Eight of the 9 strokes in the nonoperated group occurred within 9 months of diagnosis of the high-grade lesion; none were preceded by a transient ischemic attack. There was 1 perioperative stroke (1.8%) but no in-hospital operative deaths and no difference in the late death rates of the two groups. This suggests that the preservation of neurologic status in patients with asymptomatic high-grade internal carotid artery stenosis can be improved by carotid endarterectomy.

Actuarial Analysis↗
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Clinical and duplex ultrasound follow-up after balloon angioplasty for atherosclerotic renal artery stenosis.

The purpose of this study was to investigate changes in blood pressure and renal function after percutaneous renal artery balloon angioplasty in hypertensive patients with atherosclerotic renal artery stenosis. Renal artery lesions were assessed by duplex ultrasound before and after renal artery balloon angioplasty. Renal arteries were classified as normal, < 60% stenosis, > or =60% stenosis, and occluded according to previously validated duplex criteria. Data regarding risk factors for atherosclerosis and years of hypertension were collected. Systolic and diastolic blood pressure, creatinine, and number of medications were obtained before and after intervention. The immediate technical outcome of renal artery angioplasty was classified based on the arteriographic result as follows: success (residual stenosis < or =30%), partial success (residual stenosis 31-50%), or unsuccessful (residual stenosis > 50%). For bilateral procedures, success required both renal arteries to be classified as technical successes; a technical success on one side only was classified as partial success. The blood pressure response to intervention was classified as follows: cure (diastolic blood pressure < or =95 mm Hg on no medications), improved (control of blood pressure with a significant reduction in number of medications or control of previously elevated blood pressure without a change in medications), or failed (all other responses). The study group included 28 patients (14 men, 14 women) with a mean age of 65 years. The preintervention and the first postintervention evaluations occurred within 180 days of the procedure. All patients were hypertensive, and all except one were under medical treatment. Mean duration of hypertension was 9.1 +/-8.8 years. There were 38 interventional procedures (28 unilateral, 10 bilateral) involving 41 renal arteries; seven arteries had two procedures done. Before angioplasty, all renal arteries had lesions of > or =60% diameter reduction by duplex scanning. Endovascular stents were deployed following angioplasty in 14 (34%) of the procedures. The technical result was classified as a success in 24 (63%), a partial success in 12 (32%) of the procedures, and two procedures (5%) were classed as technical failures. There were statistically significant reductions in blood pressure following successful and partially successful procedures, but cure of hypertension was achieved in only 11% of cases. There were no significant changes in creatinine in any of the technical result groups. Of the 38 renal arteries evaluated with duplex ultrasound following intervention, 39% were found to have stenosis of > or =0% involving a treated renal artery, including one postintervention occlusion. Cure of hypertension was rare in this patient population with atherosclerotic renal artery stenosis. More than one third of the treated renal arteries showed > or =0% lesions recurring after the procedure. Thirteen percent of those with technical success and 17% of those with partial technical success had creatinine improvement of at least 20% over the baseline value. Significant clinical and anatomic improvement were relatively uncommon following balloon angioplasty in this series of patients.

Aged↗
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Invasive and noninvasive techniques in the detection and evaluation of acute venous thrombosis.

There are a variety of noninvasive testing procedures which can be used to establish the diagnosis of acute venous thrombosis with a high degree of certainty. For prospective screening of patients at risk, only 125I-labelled fibrinogen is of value, but does have a false positive rate of 21%. Its greatest problem is that it must be given prior to the event and, furthermore, it is not accurate in the upper thigh or the region of the iliac veins. Doppler ultrasound, plethysmography and phleborheography are accurate methods of detecting thrombi which involve the major veins of the limb from the level of the tibial veins below the knee to the level of the iliac veins in the abdomen. If properly performed, the sensitivity and specificity should exceed 90% in experienced laboratories. Contrast phlebography remains the best method of demonstrating venous thrombosis but does have limitations with regard to costs, pain to the patient and the production of thrombosis in a small percentage of patients. Furthermore, if the injections are done at the foot level, at least 18% will have inadequate visualization of the iliac veins, a critically important venous segment. It use must be restricted to those situations in which the noninvasive tests are equivocal or the information is absolutely essential for a therapeutic decision.

Doppler Effect↗
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Diagnostic considerations in occlusive arterial disease.

The diagnostic approaches to the problem of occlusive arterial disease have been reviewed. The history and physical examination are most useful in establishing the diagnosis, localizing the most proximal level of the arterial involvement, and categorizing the patient's stage of disease. Functional evaluation of limb blood pressures and flow velocity at rest and after exercise provide useful data for estimating the degree of the arterial involvement, and this information can be used as the baseline for evaluating the effects of therapy.

Arteriosclerosis↗
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Carotid artery disease in NIDDM diabetes.

A prospective study of 135 controls, 286 non-insulin-dependent diabetic patients, and 31 subjects with an elevated fasting plasma glucose was performed to assess the prevalence of high-grade carotid artery stenosis. The carotid artery evaluation was performed using an ultrasonic duplex scanner. When those patients with an elevated fasting plasma glucose and non-insulin-dependent diabetes were considered together, the prevalence was 8.2% as compared with 0.7% for the controls (P = 0.0007). Those risk factors found to be significantly related to the higher prevalence of carotid disease in the combined groups of patients included age, ratio of systolic blood pressure to diastolic blood pressure, plasma cholesterol, and cigarette smoking. These findings may be an explanation for the greater incidence of stroke in patients with diabetes mellitus.

Adult↗
PubMedDate not supplied

Management of internal carotid artery occlusion.

Although attempts to restore patency of occluded internal carotid arteries are now rarely made, endarterectomy in the contralateral artery, external carotid endarterectomy and until recently EC/IC bypass have remained surgical options in the management of such patients. Over a four-year period at this institution 104 patients underwent carotid endarterectomy for stenosis. In this group the contralateral carotid was patent (Group A). Fifty-four patients with unilateral carotid artery occlusion underwent contralateral endarterectomy (Group B), 8 underwent ECA/ICA bypass (Group C) and 4 an ECA endarterectomy (Group D). No statistically significant difference was noted in perioperative stroke and death rates for Groups A and B were (1% and 1%) and (3.7% and 1.9%) respectively. One Group C patient died from perioperative stroke (12.5%). For late events the life table adjusted annual rates for stroke and mortality were similar, Group A (stroke 2.1% and death 5%), and Group B (stroke 1.6% and death 5%). In Group C stroke rate was 10% and death 3%. All four patients undergoing ECA endarterectomy were relieved of their symptoms. It is concluded that in patients with internal carotid artery occlusion TEA may be performed with perioperative morbidity and mortality rates comparable to those when the opposite carotid artery is patent. The late outcome for stroke compares favorably with the reported natural history of the disease and outcome for such patients treated medically in the Joint Study of Extracranial Occlusion and EC-IC Bypass Study. External carotid artery endarterectomy appears useful in the treatment of embolic events on the occluded side. ECA/ICA bypass does not appear to confer benefit.

Actuarial Analysis↗
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Duplex scanning and the vascular surgeon.

Until the development of ultrasonic duplex scanning, the only diagnostic test that was able to study vascular disease wherever it occurred was angiography. Duplex scanning found its initial place for the evaluation of the carotid bifurcation. With improvements in technology, a range of transmitting frequencies, better transducers, and computer assisted algorithms, the application of this method has been greatly extended. We now have the capability of evaluating every major vascular bed of interest to the vascular surgeon. For the first time, we can now both screen and follow patients without resorting to angiography.

Arterial Occlusive Diseases↗