Search PubMed⌕ Search

Biomedical subjects

N Labropoulos

Publications and source records attributed to N Labropoulos.

At least 55 records · Page 3Linked to original sources
PubMed1998

The management of venous aneurysms of the lower extremities.

Vein aneurysms have been reported in both the deep and superficial vein system of the lower extremities. In the iliofemoral area of the deep system the most common presentation is of an abdominal or iliac fossa mass while thromboembolism is not uncommon. The aneurysms are thought to result mainly from a congenital weakness of the vein wall, with an AV fistula present in over 50% of cases. Existing AV fistulae must be ligated; however, as the results of simple AV fistula or vein ligation are poor, reconstruction should always be attempted. Aneurysm excision with an end-to-end anastomosis might be feasible in the proximal iliac segment while the use of PTFE grafts or the LSV seems appropriate in cases of attempted reconstruction. In the popliteal area there is agreement on the aetiology (congenital, traumatic, post operative and after an AV fistula formation), the symptomatology (mainly thromboembolism) and the diagnosis (duplex scanning). Symptomatic cases should be treated surgically since the reported surgical results are excellent while the incidence of recurrent pulmonary embolism in patients treated conservatively exceeds 80%. Asymptomatic popliteal vein aneurysms could remain under close observation only but, if complicated with thromboembolism during the follow-up period, surgery should be performed immediately. The crural and superficial veins represent a minor danger and can be easily treated with ligation and/or excision with excellent results.

Aneurysm↗
PubMed1997

The role of venous outflow obstruction in patients with chronic venous dysfunction.

OBJECTIVE: To quantify the functional venous outflow obstruction with different location and extent of obstruction attributed to previous deep vein thrombosis. DESIGN: Case-control study. SETTING: Vascular Laboratory, St Mary's Hospital Medical School, London, England. PATIENTS: Two groups: group 1, 25 case patients and 9 control subjects, and group 2, 45 case patients and 30 control subjects. INTERVENTIONS: Ascending venography, duplex scanning, air plethysmography, and venous pressure measurements in the foot and the arm via a 21-gauge butterfly needle. MAIN OUTCOME MEASURES: Venous outflow fraction (VOF), venous outflow resistance (VOR), and arm-foot pressure differential (A-F PD) at rest and after reactive hyperemia. RESULTS: Venous outflow resistance was evaluated in group 1. Twenty-two case patients underwent VOF testing, and 16 had A-F PD measurement performed. Case patients in group 2 underwent VOF testing. Signs and symptoms of chronic venous dysfunction were associated with the anatomical extent of obstruction. Limb swelling and ache were present in most of the patients; skin changes were noted in about 30% and ulceration in 10% of patients. The results of all tests showed no evidence of obstruction in control subjects. In most case patients with popliteal vein obstruction, test results were similar to those in control subjects: the more proximal the veins involved, the more severe the obstruction. In 16 case patients, all 3 tests were performed and agreement between A-F PD and VOR test results was found in 14 of them. The VOF test results agreed with the results of A-F PD and VOR tests in 9 case patients. In group 2, 50% of the limbs with obstruction proximal to the popliteal vein had a reduced VOF, which became worst in the limbs with extensive obstruction, particularly when the iliac veins were involved. Of the 73 limbs tested for VOF in both groups, only 7 limbs (9.6%) had their venous outflow markedly reduced by occlusion of the superficial veins. CONCLUSIONS: The anatomical extent of venous obstruction and the development of collateral circulation determine the hemodynamic severity of the chronic venous obstruction. The deep collaterals seem to be more important than the superficial venous system in bypassing the obstruction. The VOR and the A-F PD tests can be used to identify those patients who have venous obstruction, whereas the use of the VOF test may reduce the need for performing the above tests in 50% of the patients.

Adult↗
PubMed1997

Where does venous reflux start?

PURPOSE: This study was designed to identify the origin of lower limb primary venous reflux in asymptomatic young individuals and to compare patterns of reflux with age-matched subjects with prominent or clinically apparent varicose veins. METHODS: Forty age- and sex-matched subjects with no symptoms (age, 15 to 35 years; 80 limbs; group A), 20 subjects (age, 19 to 32 years; 40 limbs) with prominent but nonvaricose veins (n = 26 limbs; group B), and 50 patients (age, 17 to 34 years; 100 limbs) with varicose veins (n = 64; group C) were examined with color flow duplex imaging. All proximal veins (above popliteal skin crease), superficial, perforator, and deep, in the lower limb were examined in the standing position, and all the distal veins in the sitting position. Patients who had a documented episode of superficial or deep vein thrombosis, previous venous surgery, or injection sclerotherapy were excluded from the study. RESULTS: The prevalence of reflux in group A was 14% (11 of 80), in group B 77% (31 of 40), and in group C 87% (87 of 100). In more than 80% of limbs in the three groups, reflux was confined to the superficial veins alone. Deep venous reflux or combined patterns of reflux were uncommon even in group C. Reflux was detected in all segments of the saphenous veins and their tributaries. In the 125 limbs that had superficial venous incompetence, the below-knee segment of the greater saphenous vein was the most common site of reflux (85, 68%), followed by the above-knee segment of greater saphenous vein (69, 55%) and the saphenofemoral junction (41, 32%). Nonsaphenous reflux was rare (3, 2.4%). Reflux in the lesser saphenous vein (21, 17%) was seen in all groups, whereas involvement of both greater and lesser saphenous veins (8, 6.4%) was seen in group C alone. The incidence of multisegmental reflux was significantly higher in group C (61 of 64, 95%) than in group A (two of 11, 18%) or group B (14 of 26, 54%). The prevalence of distal reflux was comparable in all groups. CONCLUSIONS: Primary venous reflux can occur in any superficial or deep vein of the lower limbs. The below-knee veins are often involved in asymptomatic individuals and in those who have prominent or varicose veins. These data suggest that reflux appears to be a local or multifocal process in addition to or separate from a retrograde process.

Adolescent↗
PubMed1997

Prevalence and clinical significance of posterolateral thigh perforator vein incompetence.

PURPOSE: Posterolateral thigh perforator (PLTP) veins are part of the lateral thigh venous system, which in most people remains undeveloped. This study was designed to determine the prevalence and clinical significance of these veins. METHODS: Over the past 6 years, 2820 lower limbs with signs and symptoms of chronic venous disease (CVD) were evaluated for venous reflux using color flow duplex imaging. Superficial, perforating, and deep veins were examined in the standing, sitting, and reversed Trendelenburg positions. PLTP veins were best identified in the standing position with the patient facing away from the examiner. RESULTS: Twenty-six incompetent PLTP veins were found in 24 limbs (0.85%) of 21 patients (mean age, 43 +/- 16 years; range, 22 to 77 years). All PLTP veins pierced the fascia lata 12 to 25 cm (mean, 16 +/- 3 cm) above the popliteal skin crease in the lateral aspect of the thigh. At this level, the PLTP veins dove posteriorly 3 to 8 cm to join primarily tributaries of the deep femoral vein, superficial femoral vein, or both. Eight PLTP veins were duplicated at 1 to 2 cm below the fascia. Seven PLTP veins gave rise to superficial tributaries that were extended to the lower lateral and posterior thigh, whereas the remaining 19 PLTP veins gave rise to tributaries alongside the lesser saphenous vein and the anterior arch of the greater saphenous vein. On nine occasions, reflux was found in the PLTP veins and their associated tributaries alone. In all of these cases, reflux was adequately controlled with a tourniquet placed distal to the fascial defect. In the remaining 17 PLTP veins, reflux was also seen in the greater saphenous vein, the lesser saphenous vein, or both. None of the limbs that had PLTP vein reflux alone exceeded CVD class 3. When PLTP vein reflux was combined with saphenous reflux, there were five limbs classified as CVD class 4 and one limb each as CVD classes 5 and 6. Twenty limbs underwent ligation and stripping of the varicosities. Three of the earlier patients in the series underwent incomplete operations, which resulted in immediate residual varicosities from the PLTP tributaries. All three patients underwent reoperation successfully within a year. CONCLUSIONS: The prevalence of PLTP vein reflux is quite low. Reflux in the PLTP veins alone is associated with mild to moderate clinical presentation. However, when it is combined with saphenous reflux skin damage can be present. Failure to recognize PLTP veins may result in an incomplete or unnecessary operation, leaving the patients with residual varicose veins.

Adult↗
PubMed1997

Carotid endarterectomy for recurrent stenosis.

PURPOSE: The purpose of this study was to report our results in the surgical management of recurrent carotid stenosis (RCS) after carotid endarterectomy (CEA). METHODS: In a 20-year period, we performed 1209 CEAs; 82 operations (6.8%) were for RCS. There were 33 men and 36 women, with an average age of 66.3 years. Nine patients underwent two redo CEAs and two patients underwent three redo CEAs for either bilateral recurrence or a second recurrence on the same side. Overall, 10 patients were identified with a second recurrence. RESULTS: The average time to presentation with RCS was 65 months (range, 3 to 361 months). The majority of patients (66%) were symptomatic, 34% had transient ischemic attacks, 17% had amaurosis fugax, 9% had strokes, and 6% had nonhemispheric symptoms. Before repair, angiograms were obtained. Patch repair was performed in 61 procedures (74%), 41 with vein, 11 with Dacron, and nine with polytetrafluoroethylene. Autogenous or synthetic bypass grafts were used in 20 procedures (24%), vein in eight, Dacron in two, and polytetrafluoroethylene in 10. In one patient, an occluded internal carotid artery was ligated and an endarterectomy of the external carotid artery was performed without a patch. The operative stroke rate was 4.8%. Minor complications included transient or permanent cranial nerve deficits in 7.3% and wound hematomas in 2.4%. CONCLUSION: Although repeat endarterectomy to treat RCS is technically more demanding, it can be performed safely. Long-term follow-up examination shows that a second recurrence may develop, and we recommend serial noninvasive testing.

Aged↗
PubMed1997

Pre-bypass quality assessment of the long saphenous vein wall with ultrasound and histology.

OBJECTIVES: Pre-existing unsuspected wall changes in saphenous vein grafts have been implicated in the graft outcome. Pre-bypass assessment of the vein may identify grafts at high risk for failure. This study was conducted to evaluate preoperatively the quality of the long saphenous vein (LSV) wall with ultrasound and histology. DESIGN: Prospective clinical study. MATERIAL AND METHODS: Three particular LSV segments, ankle, knee and mid-thigh, were evaluated preoperatively by ultrasound in 40 limbs of 38 patients, candidates for coronary artery bypass grafting. The venous wall was characterised based on its thickness and echogenicity in three categories: normal, moderately and severely fibrotic. LSV specimens taken from the above sites were also grouped into the same three categories based on their fibrotic content found on histology. RESULTS: In total, 89 vein specimens were evaluated. On ultrasound, 81 specimens were detected as normal (91%), seven as moderately (8%) and one as severely fibrotic (1%). On histology, only eight specimens were found normal (9%), 75 with moderate (84%) and six with severe fibrosis (7%). Similar wall characterisation with both examinations was found in only 19% (17/89) of the specimens. Eighty-one specimens (91%) had some degree of fibrosis on histology. Different grades of fibrosis were found on histology in different sites of the same vein. CONCLUSIONS: Pre-existing wall changes are very common in vein grafts used for bypass surgery. However, the ultrasonic characterisation of the venous wall preoperatively cannot reliably identify these changes.

Aged↗
PubMed1996

The role of venous reflux and calf muscle pump function in nonthrombotic chronic venous insufficiency. Correlation with severity of signs and symptoms.

OBJECTIVE: To determine the lower-limb venous hemodynamics in patients with varying grades of chronic venous insufficiency (CVI), not due to deep vein thrombosis, when matched for age and duration of disease. DESIGN: Case-control study. SETTING: Normal volunteers and patients with different grades of CVI referred to the vascular unit of a university hospital. MATERIALS: Fifty-one legs (40 patients) with CVI, but without a history of deep vein thrombosis, and 24 normal legs (20 volunteer subjects). These selected legs were grouped according to the severity of CVI (classes 0 - through 3) so that each class was matched for age (all study participants <60 years) and duration of signs and symptoms (<10 years). INVESTIGATIONS: Air plethysmography and color flow duplex imaging. MAIN OUTCOME MEASURES: Venous volume, venous filling index, and outflow, ejection, and residual volume fractions were assessed in all limbs with air plethysmography. The presence of reflux was confirmed by the results of color flow duplex imaging. RESULTS: Ten (42%) of 24 limbs in class 0 had no reflux. Twenty-five (57%) of the 44 limbs in classes 0 and 1 had superficial reflux alone, while all the limbs in class 1 had some degree of reflux in the superficial veins. The sites of reflux in these limbs were similar. The patterns of reflux in classes 2 and 3 were more complex. Eight (26%) of the 31 limbs had superficial reflux alone, whereas 10 (32%) had all three systems involved (superficial, deep, and perforating). The venous volume, venous filling index, and residual volume fraction worsened with progression of CVI. Significant statistical differences could, however, only be demonstrated between classes 0 and 1 vs classes 2 and 3. No changes could be found in the ejection and outflow fractions. CONCLUSIONS: Patients (age <60 years) with CVI of less than 10 years' duration and with no history of deep vein thrombosis had venous hemodynamic changes that correlated well with the clinical severity of the disease. This was owing to the increased reflux, as the ejecting ability of the calf muscle pump remained intact, and the venous outflow was normal.

Adult↗
PubMed1996

Recurrent varicose veins: investigation of the pattern and extent of reflux with color flow duplex scanning.

BACKGROUND: This study was conducted to investigate with color flow duplex imaging the patterns and the extent of venous valvular incompetence in recurrent varicose vein disease. METHODS: One hundred thirty-four limbs of 123 unselected patients who arrived in the outpatient clinic with residual or recurrent varicose veins after undergoing an operation were included. Limbs with history of compression sclerotherapy before or after the operation were excluded. The long (LSV) and short saphenous vein (SSV) systems in all limbs were examined with color flow duplex imaging for detection of the sites and the extent of reflux. RESULTS: Various patterns of recurrent valvular reflux were seen in both the LSV and SSV systems. Reflux confined to saphenofemoral junction alone or associated with reflux in the LSV system was seen in 29% of the limbs. Reflux in the whole LSV system was very common after saphenofemoral junction ligation was performed (chi-squared test, p<0.01). Most of the limbs (53%) with recurrence in the LSV system had incompetent perforating veins. Incompetent perforators in the thigh were more common after ligation (23%) than stripping (10%), but this finding was not true in the calf. After saphenopopliteal junction ligation was performed, the more common pattern was the reflux in the SSV (75%), whereas after SSV stripping was performed, it was the reflux in the SSV tributaries (64%). CONCLUSIONS: Multiple patterns of reflux develop in recurrent varicose veins. Precise mapping of the reflux and identification of the possible causes are required to instigate appropriate treatment. Color flow duplex imaging is an efficient noninvasive diagnostic technique to identify venous reflux.

Adult↗
PubMed1996

The role of the distribution and anatomic extent of reflux in the development of signs and symptoms in chronic venous insufficiency.

PURPOSE: The purpose of this study was to identify the distribution of venous reflux in patients with different patterns of reflux with each class. METHODS: Color-flow duplex imaging was used to evaluate the entire venous system from groin to ankle in 465 patients (594 limbs) belonging to different clinical CVI classes (0, 1, 2, and 3). A history of previous superficial thrombophlebitis was present in five limbs and past deep vein thrombosis in 70. RESULTS: One hundred seventy eight (30%) limbs were normal and the remaining 416 (70%) had venous incompetence. Deep reflux was present exclusively in 19 limbs (3.2%), and the perforation system alone was involved in only three limbs (0.5%). However, isolated superficial incompetence was seen in 186 limbs (31.3%) and a combination of superficial with perforating alone was involved in 45 (7.6%). Incompetence in all three systems was seen in 99 extremities (16.7%). In addition, the superficial system was involved in 390 limbs, the perforators in 151, and the deep system in 178 limbs. Only a small percentage of those in class 0 had reflux, and most of them had a single site of incompetence. In class 1 the majority of the limbs had superficial reflux (90.3%), 10.3% of the limbs had deep venous reflux, and 6.9% were competent. Reflux in the superficial system was only seen in 80.7% of the limbs in class 1 and in one fifth of the limbs in classes 2 and 3. Isolated deep or perforated incompetence was rare in all classes. Variable combined patterns of reflux were seen more often in classes 2 and 3 (p < 0.0001). In classes 2 and 3 there were no differences in the number of incompetent sites in the superficial and deep venous systems or the patterns of reflux (p > 0.1). The number of incompetent perforators in class 3 tended to be higher than that in class 2, especially in the below-knee segment, but no significant differences were seen. Distal reflux was present in the majority of the limbs in all symptomatic classes (1, 2, and 3). CONCLUSIONS: The distribution and extent of reflux is strongly associated with clinical severity of CVI through class 2. Distal venous reflux is present in at least 80% of the symptomatic limbs. Deep venous thrombosis may not be a prerequisite for the development of skin changes or ulceration in about 75% of the limbs. Superficial venous surgery could be beneficial to at least one third of patients with skin changes or ulceration.

Adult↗
PubMed1996

The role of common carotid artery end-diastolic velocity in near total or total internal carotid artery occlusion.

OBJECTIVES: To evaluate the role of the end-diastolic velocity (EDV) in the common carotid artery (CCA) as a marker of internal carotid artery (ICA) occlusion. DESIGN: Validation of retrospective data in a prospective clinical study. METHODS: The EDV in 94 patients with total ICA occlusion and in 24 patients with high grade (95-99%) unilateral ICA stenosis identified on extracranial carotid colour-flow Duplex imaging (CFDI) and arteriography was reviewed, and was retrospectively compared to the EDV of 176 normal individuals. Identification of patients with ICA occlusion was most accurate (99.3%) with an ipsilateral EDV > or = 12 cm/s and a DIFF > or = 10 cm/s (DIFF = contralateral EDV -- ipsilateral EDV). These values were then prospectively applied to all 886 patients (67 with high grade stenosis or occlusion) who underwent CFDI at our institution during 1994. RESULTS: The EDV > or = 12 had a 92% sensitivity, a 99.4% negative predictive value (NPV) and a 85% specificity in distinguishing between occluded and patent ICA's. In combination with a DIFF > or = 10 was 80.4% sensitive and 97.5% specific. The positive predictive value of the EDV > or = 12 in the distinction between 95-99% ICA stenosis and ICA occlusion was 78.3%, and that of the combination was 85.4%. The EDV was rarely zero and 10% of patients with normal or minimally diseased ICA's had an EDV > or = 12 and/or a DIFF > or = 10. CONCLUSIONS: The EDV < or = 12 cm/s is a sensitive marker of ICA occlusion with a high NPV and in combination with the DIFF > or = 10 cm/s, is specific. Nevertheless, EDV parameters are inaccurate in the distinction of 95-99% ICA stenosis from occlusion. Low EDV can be found in a number of patients with minor or no ICA disease, particularly in those with a stroke or silent cerebral infarct.

Adult↗
PubMed1996

Laser Doppler flux in normal and arteriosclerotic carotid artery wall.

The perfusion of the arterial wall was evaluated in vivo in normal sections of the carotid artery, in sections with fibrotic plaques and in sections with plaques and diffuse calcifications using laser Doppler flowmetry. Patients with carotid plaques undergoing carotid endarterectomy were studied. Using intra-operative ultrasound three different levels of atherosclerosis involvement of the arterial wall were defined: normal arterial wall where all components (intima, media and adventitia) were clearly separated and intact; wall with intima-media thickening and fibrotic plaques (without calcifications); sections with diffusely calcified plaques. In 20 patients 20 normal sections, 20 sections with fibrotic plaques and 20 sections with large plaques and diffuse calcifications were studied. Diabetic and hypertensive patients were excluded. Wall flux was measured on the external surface of the common carotid artery before complete dissection for endarterectomy. Measurements were recorded when at least 3/4 of the adventitia was intact for a length of at least 4 cm. The average flux in normal sections was higher (p < 0.05) than in sections with fibrotic plaques and in sections with calcified plaques. A significant difference in flux (p < 0.05) between fibrotic (decreased flux) and calcified areas (very low flux) was recorded. In conclusion a higher wall perfusion was observed in normal arterial sections in comparison with sections with plaques. Sections with diffuse calcifications and larger plaques had a very low flux.

Aged↗
PubMed1996

The impact of duplex scanning on vascular practice.

Duplex ultrasonography has gained enormous importance in the vascular practice over the last decade. Technological development with the colour application as well as the high resolution imaging have altered the diagnostic approach, treatment and follow-up of the vascular patients. Research on the epidemiology and natural history of atherosclerosis and thrombosis has also been founded based on the ultrasonic applications, improving our understanding in the pathophysiology of the vascular disease. This article presents an overview of the revolutionary role of the ultrasonic investigations in the arterial and venous disease and outlines the possible limitations of the technique. Financial aspects of its use in the health care system and potential advents in the near future are also discussed.

Aortic Diseases↗
PubMed1995

Venous hemodynamic abnormalities in patients with leg ulceration.

PURPOSE: Venous ulceration in the leg has been predominantly associated with deep venous insufficiency, although a few reports have implicated the superficial veins. The aim of this study was to identify the distribution of valvular incompetence in patients with active leg ulceration. PATIENTS AND METHODS: Color flow duplex imaging (CFDI) ultrasonography was used to evaluate the entire venous system--superficial, perforator and deep--from groin to ankle in 112 limbs of 94 patients with venous leg ulcers. RESULTS: Seventy two limbs (64%) had multisystem incompetence and 36 (32%) had one system involved only, whereas in 4 limbs (4%) there was no venous incompetence. Deep venous reflux exclusively was present in 7 limbs (6%) and the perforator system alone was involved only in 3 limbs (3%). However, isolated superficial incompetence was seen in 26 extremities (23%) and combination of superficial with perforator system alone in 23 (21%). In addition, reflux overall in the superficial system (alone and in combination with perforator and deep systems) was seen in 94 limbs (84%). The most common pattern (28%) of abnormality was reflux in all systems, superficial, perforator, and deep. CONCLUSIONS: The results of this study show that variable combined patterns account for over two thirds of patients with ulceration. No comprehensive surgical policy for alleviating ulceration can be justified; we suggest that a complete evaluation of all venous systems from groin to ankle with CFDI ultrasonography in patients with venous ulceration is practical on a routine basis and will be particularly valuable before surgery in order to target intervention at specific incompetent sites.

Adolescent↗
PubMed1995

New insights into the pathophysiologic condition of venous ulceration with color-flow duplex imaging: implications for treatment?

PURPOSE: This study was conducted to investigate the distribution of reflux in the veins adjacent to or within the venous ulcer (local) and to correlate it with the pattern of disease of the axial veins (all veins away from the ulcer area) of the affected limb. METHODS: Forty-three ulcers in 34 legs of 33 patients were examined with color-flow duplex imaging. The veins in the area of the ulcer were scanned with a sterile technique. RESULTS: In 17 legs (50%) there was documented past deep venous thrombosis. All of the 34 limbs had reflux in the superficial or deep axial veins either alone or in combination. Fifteen of these limbs (44%) also had perforating vein incompetence, but none had perforator incompetence alone. Six ulcers showed no evidence of reflux in the local veins when scanned through the ulcer bed despite the presence of reflux in the axial veins of the limb. In 13 limbs with 17 ulcers, either the superficial axial veins alone or the deep axial veins alone were affected (with or without associated perforator incompetence). Examination of the local veins associated with these 17 ulcers revealed a similar pattern of reflux to that seen in the axial veins in 13 cases, with the remaining 4 ulcers showing no local venous abnormality. The pattern of reflux was less predictable at the local ulcer level in limbs where both superficial and deep venous incompetence coexisted in the axial veins. Only 7 of the 26 ulcers (27%) in these limbs had similar evidence of combined superficial and deep reflux in the local ulcer veins, whereas 10 ulcers (39%) were associated with local reflux in the superficial or deep veins alone. CONCLUSIONS: These data show that 86% (37/43) of the ulcers has some degree of reflux in the local area, the pattern of which may differ from the axial vein disease. Treatment of the local hemodynamic abnormalities may be an important factor in the healing of the ulcers and in the prevention of their recurrence.

Adolescent↗