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Biomedical subjects

G Szendro

Publications and source records attributed to G Szendro.

32 records · Page 2Linked to original sources

Beware of absent femoral pulse (or how to prevent major complications after minor procedures).

The following is presented to illustrate the importance of examining all peripheral pulses, especially the femoral pulse, before performing minor surgical procedures on the lower extremity, even limited toe amputation. This simple examination is a must in identifying patients at risk for severe peripheral arterial insufficiency, which can lead to major complications if underestimated or undiagnosed. We offer three examples to illustrate this point. All patients underwent successful revascularization and major lower limb amputation was avoided.

Aged↗

The relation of venous ulceration with ambulatory venous pressure measurements.

Two hundred thirty-six limbs of 220 unselected patients who were admitted with venous problems (83 with ulcers) were studied with continuous-wave Doppler ultrasonography, duplex scanning, and ambulatory venous pressure measurements. Patients with evidence of deep venous disease because of reflux or obstruction in the deep veins on Doppler and duplex ultrasonic examination or with an ambulatory venous pressure greater than 45 mm Hg despite the ankle cuff had venography. One hundred fifty-three limbs had superficial venous disease (reflux in the superficial veins with competent popliteal valves), and 83 limbs had deep venous disease (popliteal reflux on duplex examination or deep venous obstruction on venography). No ulceration occurred in limbs with ambulatory venous pressure < 30 mm Hg, and there was a 100% incidence with ambulatory venous pressure > 90 mm Hg. A linear increase occurred from 14% in limbs with ambulatory venous pressure between 31 and 40 mm Hg to 100% in limbs with ambulatory venous pressure greater than 90 mm Hg (r = 0.79). In the groups studied, an increased incidence of ulceration was associated with an increase in ambulatory venous pressure irrespective of whether the venous problem was the result of superficial or deep venous disease. Ambulatory venous pressure has both diagnostic and prognostic significance in patients with venous disease.

Blood Flow Velocity↗

Measurement of the ultrasonic intima-media complex thickness in normal subjects.

PURPOSE: The evolution of atherosclerosis can be studied before development of symptomatic plaque by evaluating morphologic changes of the intima-media (I-M) complex, seen on high-resolution ultrasonography of the arterial wall. These qualitative changes require large alterations in vessel wall appearance to recognize progression of atherosclerosis. It has been suggested that measurement of the thickness of the I-M complex may be a quantitative and more sensitive method of assessing these early atherosclerotic changes. METHODS: High-resolution ultrasonography has been used to measure the thickness of the I-M complex in 140 symptom-free subjects. RESULTS: The mean thickness of the I-M complex of the common carotid arteries was linearly related to the age (r = 0.77; p < 0.001), pack-years of smoking (r = 0.39; p < 0.05), the systolic blood pressure (r = 0.51, p < 0.01), and to the arterial ultrasound score (r = 0.85). The arterial ultrasound score has previously been shown to correlate with the presence of asymptomatic myocardial ischemia and with the development of cardiovascular symptoms. The mean thickness of the I-M complex in subjects without plaque (in the common carotid or common femoral artery bifurcations) was significantly thinner than in subjects with plaque (p < 0.001). CONCLUSION: The thickness of the I-M complex of the common carotid arteries is a measure of the risk for the development of cardiovascular symptoms in symptom-free individuals.

Adolescent↗

Asymptomatic carotid artery bifurcation disease in patients with claudication.

A study was undertaken to determine the prevalence of asymptomatic atherosclerotic carotid artery bifurcation disease in patients presenting with claudication; thus 263 consecutive patients with intermittent claudication, but without recent or old cerebrovascular symptoms were studied by routine carotid duplex scanning. Of the 263 patients, 124 (47.1%) had a C, D, D+ or E lesion in some vessels of the carotid bifurcation and 54 (20.5%) had a D, D+ or E lesion of the common or internal carotid arteries. Women had a higher prevalence of significant carotid stenosis (29.6% v. 18.2% in men) as did patients over the age of 70 years (28.6% v. 16.3% if below 70 years). It is concluded that the prevalence of clinically significant carotid bifurcation disease (greater than 50% stenosis in the common or internal carotid arteries) in patients with claudication is high (20.5%). The presence of an asymptomatic high-grade stenosis (D+ or E) in 11.8% of patients with claudication should alert the clinician that he is treating a patient who is at a high risk of developing cerebrovascular ischaemic complications.

Aged↗

The effect of elastic compression on the venous tone in patients with varicose veins.

The long term effect of elastic compression, with an emphasis on the changes in venous wall elasticity, was studied in 10 limbs with varicose veins. By simultaneously measuring venous volume, using the air plethysmograph (APG), and venous pressure, while the venous outflow was occluded, the pressure/volume (P/V) relationship of the venous system of the leg could be studied and the elastic modulus calculated. These measurements were performed prior to the application of elastic stockings and 6 weeks later, one day after the stockings had been removed. Statistically significant improvements were noted in the APG parameters studied and in the P/V curve derived elastic modulus calculations. The limbs could be divided into two groups based on the response of the P/V curves to elastic stockings and the severity of disease. Those limbs with milder disease tended to shift their P/V curves downward and to the right after compression (giving them a more normal pattern). Limbs with more severe disease showed evidence of a similar pattern of improvement at low but not at high venous pressures.

Bandages↗

Haemodynamic significance of incompetent calf perforating veins.

A total of 149 consecutive unselected patients (221 limbs) who presented with signs and symptoms of chronic venous problems (varicose veins with or without ankle oedema, skin changes and leg ulcers) have been studied by clinical examination, ascending deep to superficial venography, Doppler ultrasound and ambulatory venous pressure measurements. Of the limbs, 180 (82 per cent) had varicose veins without obstruction in the deep veins or reflux in the popliteal or femoral veins while 41 (18 per cent) had deep venous disease. Of the 180 limbs with 'primary' varicose veins 110 (60 per cent) did not have incompetent calf perforating veins (group A) while 70 (40 per cent) did (group B). On the basis of the ambulatory venous pressure after calf muscle exercise and the refilling time, the incompetent calf perforating veins of limbs in group B belonged to three subgroups of different haemodynamic significance. In 20 limbs (30 per cent) they were found to be of no haemodynamic significance, in 25 (35 per cent) of moderate haemodynamic significance and in 25 (35 per cent) of major haemodynamic significance. The last were, on clinical examination, indistinguishable from limbs with deep venous disease although they had patent deep veins with competent popliteal valves.

Humans↗

Venous reflux: quantification and correlation with the clinical severity of chronic venous disease.

Air-plethysmography has been used to measure, in ml and in ml 100 ml-1 of tissue, the blood volume that filled the leg veins on changing posture from the recumbent position to standing. The venous filling index (VFI) (average filling range) was measured in ml s-1 and in ml 100 ml-1 min-1. We studied 24 normal legs (N), 21 with primary varicose veins without chronic swelling, skin changes (liposclerosis, eczema, pigmentation) or ulceration (PVV) and 59 with chronic swelling and/or skin changes and/or ulceration; of these 59 legs, 31 had primary varicose veins (PVV/S) and 28 had popliteal reflux (PR). The classification was done according to clinical examination, Duplex scanning, ambulatory venous pressure measurements and venography. There was an increased incidence of sequelae with increasing values of VFI. The incidence of these sequelae was irrespective of whether reflux was in the deep or in the superficial veins. VFI is a practical non-invasive measurement of reflux. It should be used to study the effect of therapy and particularly to evaluate new reconstructive procedures designed to abolish reflux in the deep veins.

Adult↗

Study of the factors affecting blood viscosity in patients with thromboangiitis obliterans. A preliminary report.

Hematocrit values, plasma fibrinogen levels, and erythrocyte deformability are well-recognized factors affecting blood viscosity. We studied the incidence of abnormalities in these factors among 17 patients suffering from thromboangiitis obliterans (Buerger's disease) compared with 14 normal age- and sex-matched control subjects. Hematocrit values and fibrinogen levels were higher, whereas the erythrocyte filterability index was lower among the patients with Buerger's disease (p less than 0.001). Incubation of washed erythrocytes from these patients with control plasma of blood type AB produced an improvement of the filterability index (p less than 0.005). Our findings suggest that patients suffering from Buerger's disease show, in addition to the well-recognized arterial lesions, an abnormality in the factors affecting blood viscosity. This may contribute to a worsening of the clinical manifestations. Evidence is presented suggesting that a plasmatic factor may be responsible for the impaired erythrocyte filterability.

Blood Viscosity↗

Air-plethysmography and the effect of elastic compression on venous hemodynamics of the leg.

Leg volume changes during exercise have been measured in absolute units (milliliters) by means of a new method of air-plethysmography. Venous volume (VV), venous filling time, and venous filling index on standing from the recumbent position, ejected volume (EV) and ejection fraction (EF = EV x 100/VV) with one tiptoe movement, and residual volume (RV) and residual volume fraction (RVF = RV x 100/VV) after 10 tiptoe movements were measured in normal limbs, limbs with superficial venous incompetence, and limbs with deep venous disease. The same measurements were repeated with a graduated medium compression stocking in limbs with SVI and graduated high compression stockings in limbs with DVD. Ambulatory venous pressure was measured at the same time, with a needle in a vein in the foot. The results indicate that this method of air-plethysmography is not only of diagnostic value but offers a new and unique technique to assess and study the hemodynamic effects of different forms of elastic compression. The lower ambulatory venous pressure, produced by the elastic compression, was the result of a reduction in reflux and an improvement in the calf muscle ejecting ability during rhythmic exercise.

Adult↗

Prominent somnolence and cerebellar syndrome in subclavian artery thrombosis--a case report.

A patient suffering from acute left subclavian artery thrombosis presented with an unusual syndrome of prominent somnolence, right cerebellar signs, and left upper extremity ischemia. Clinical, angiologic, and electrophysiologic studies confirmed a brain stem and reticular formation dysfunction due to vertebrobasilar ischemia. Urgent thromboembolectomy led to neurologic improvement and satisfactory revascularization of the involved upper limb.

Acute Disease↗

Duplex scanning in the assessment of deep venous incompetence.

A noninvasive method to evaluate deep venous incompetence by duplex scanning is presented. For this test, it was decided to have the patient standing so as to make the test less dependent on the need for patient cooperation and to allow gravity to produce reflux. Results were validated against ambulatory venous pressure measurements. The method described had a sensitivity of 84% and specificity of 88%. Duplex scanning is a useful screening test for detecting the presence and site of incompetence in patients with deep venous disease.

Humans↗

Preserving the left arm vein in cases of hemodialysis access generating left internal mammary artery steal syndrome.

In patients undergoing chronic hemodialysis (HD) through an arm arteriovenous fistula (AVF), coronary insufficiency can occur if the patient undergoes a coronary artery bypass graft (CABG) using the ipsilateral internal mammary artery (1-4). Therefore, the creation of a new AVF after CABG should avoid using the arm ipsilateral to the side where the internal thoracic artery was used. In cases where coronary syndrome appears when this advice is not followed, treatment should be offered aimed at overcoming the hemodynamic interference between the diminished coronary supply through the left or right internal mammary artery by closure of the existing fistula, with or without temporary central venous line insertion until the maturation of a new fistula. We suggest a different approach by moving only the arterial inflow site of the AVF to the controlateral subclavian artery, but in addition, leaving the well functioning venous outflow tract intact. In cases of left internal mammary steal it is achieved by creating a conduit running from the right subclavian artery to the left cephalic vein; therefore, creating a new arterial inflow source, connected to the existing functioning old venous outflow tract to maintain an immediately functioning new fistula without a coronary steal.

Journal Article↗

Duplex scanning evaluation of internal carotid stenosis. Improved detection of early lesions.

New criteria for the interpretation of duplex scanning waveforms were compared with those devised by Blackshear and Strandness and revealed an improved grading of internal carotid stenosis in early lesions. The ratio of peak frequency minus first zero slope frequency divided by the peak frequency (a-b/a ratio) was found to be of no value in the discrimination between normal and any grade of carotid stenosis. The new criteria depend upon the to dental presence of spectral broadening on the upstroke of systole to differentiate between normal and abnormal, spectral broadening throughout the systolic phase above the end diastolic frequency to determine greater than 15% stenosis, peak frequency greater than 4kHz to indicate greater than 50% stenosis and the absence of a Doppler signal to indicate occlusion. Comparison with two plane selective carotid angiography revealed a Kappa statistic of 0.8 +/- 0.02 using the new criteria compared with 0.65 +/- 0.03 using the established criteria of Doppler waveform analysis.

Arteriosclerosis↗