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Biomedical subjects

N Labropoulos

Publications and source records attributed to N Labropoulos.

At least 37 records · Page 2Linked to original sources
PubMed1999

Higher prevalence of abdominal aortic aneurysms in patients with carotid stenosis but without diabetes.

BACKGROUND: We compared abdominal aortic aneurysm (AAA) prevalence in 3 groups of patients at the Hines Veterans Affairs Medical Center: (1) patients with 50% or more carotid stenosis, (2) patients with less than 50% stenosis, and (3) patients screened for the Aneurysm Detection and Management (ADAM) study. METHODS: Of all the patients referred to the vascular laboratory for carotid duplex examination during a 12-month period, patients with 50% or more carotid stenosis underwent ultrasonography of the abdominal aorta unless they had a previous scan or previous aortic surgery (group 1, n = 374). Patients with less than 50% carotid stenosis who had been screened for ADAM comprised group 2 (n = 139). They were compared with all patients screened for ADAM at our center during the same time period (group 3, n = 2477). RESULTS: AAA of 3.0 cm or more were present in 18.2%, 12.2%, and 7.2% of groups 1, 2, and 3, respectively; AAA of 4.0 cm or more were present in 8.3%, 5.8%, and 2.1% of groups 1, 2, and 3, respectively. Among patients with carotid stenosis, those patients without diabetes accounted for the observed increase in prevalence (21.9 % > or = 3.0 cm and 10.2% > or = 4.0 cm vs 9.2% and 2.8% in patients with diabetes). CONCLUSIONS: The relative risk of AAA is 2 to 3 times greater in patients with carotid stenosis compared with patients undergoing routine screening. However, only patients without diabetes account for the increased prevalence. Selective AAA screening of patients who are not diabetic with carotid stenosis is recommended.

Aged↗
PubMed1998

Acute effects of intermittent pneumatic compression on popliteal artery blood flow.

OBJECTIVES: To investigate the immediate effects of intermittent pneumatic foot and calf compression (IPFCC) on popliteal artery blood flow in symptom-free volunteers and to determine the reproducibility of color flow duplex imaging in the popliteal artery. DESIGN: Cohort study. SETTING: A university associated tertiary care hospital. PATIENTS: Forty lower limbs of 30 volunteers without symptoms or noteworthy risk factors of peripheral vascular disease. INTERVENTIONS: Popliteal artery blood flow was measured in the sitting position before, during, and after the application of IPFCC using color flow duplex imaging. The interobserver, intraobserver, and between occasion within-subject variability of the popliteal artery blood flow were evaluated in 5 symptom-free volunteers who had at least 5 color flow duplex imaging measurements taken at each of the above time points on 3 different days. MAIN OUTCOME MEASURES: The arterial diameter, peak systolic, end diastolic, and reverse-flow velocities were measured, as well as the duration of forward flow during diastole before, during, and after IPFCC. The same variables were measured in 5 separate volunteers by 3 different observers, on 3 separate days, at 3 separate times to determine reproducibility. RESULTS: Including all types of variability, the popliteal artery blood flow varied from 8% to 39% with a mean value of 19%. Since the diameter of the artery was obtained with less than 5% variability, the time average mean velocity was responsible for the high variation in flow. During application of the IPFCC, the popliteal artery blood flow increased significantly in all subjects (P<.001). The mean increase in the flow was 2.4 times the baseline values. The diameter of the arteries remained unchanged while the time average velocity increased significantly (P<.001). This velocity increase was due to marked elevation in the peak systolic and end diastolic velocities and diminution of the reverse-flow component, as well as a prolongation of the forward flow during diastole. After cessation of the pump, flow returned to baseline levels (P=.41) CONCLUSIONS: Ultrasound-derived popliteal artery blood flow measurements show moderate variability. The application of IPFCC greatly enhances popliteal artery blood flow. The flow increase is due to a dramatic drop in the peripheral vascular resistance as the peak systolic and end diastolic flow velocities increase and the reverse-flow component diminishes. Its role in the treatment of lower extremity occlusive arterial disease needs to be determined.

Adult↗
PubMed1998

Compensatory arterial enlargement is a common pathobiologic response in early atherosclerosis.

BACKGROUND: Human arteries are dynamic conduits that respond to different stimuli by remodeling their structure and size. Arterial dilatation has been shown to occur in moderate and advanced atherosclerosis in studies that evaluated only one artery, either coronary, carotid, or superficial femoral artery (SFA). The purpose of this study was to quantify and compare compensatory arterial enlargement throughout the peripheral vascular system in early atherosclerosis. METHODS: Seventy-two patients (40 male, 32 female, mean age 67 +/- 12 years) underwent transcutaneous B-mode ultrasound imaging during routine examinations. Thirty-nine carotid, 19 aorta, 19 iliac, 23 common femoral (CFA), 21 SFA, and 23 popliteal arteries were longitudinally imaged. Eight healthy volunteers (6 male, 2 female, mean age 27 +/- 2.2 years) had the same arteries evaluated (n = 48). Internal diameter (ID) and external diameter (ED) were measured in disease-free areas and in paired adjacent areas exhibiting increased intima-media thickening (IMT) and small atherosclerotic plaques. The percent change in ID, ED, IMT, and plaque thickness were calculated. RESULTS: There was no observed change in ID or ED in all arteries of the healthy volunteers. When compared with normal vessel segments, all arteries demonstrated a marked decrease in ID and increase in ED in areas of small, hemodynamically insignificant plaque. The aorta had a 6.00% +/- 1.92% increase in ED, which was significantly less than the percent increase in ED observed in carotid (8.14 +/- 4.5%. P = 0.05), CFA (9.73 +/- 3.54%, P = 0.0001), SFA (9.15 +/- 4.25%, P = 0.005), and popliteal arteries (9.67 +/- 4.34, P = 0.002). In all arteries there was a strong correlation between plaque thickness and percent change in ED with the best correlation observed in the popliteal artery (R2 = 0.823, P < 0.0001). IMT was significantly increased in all normal vessel segments of the patients when compared with the healthy volunteers (P < 0.001). CONCLUSION: All peripheral arteries dilate in response to intima-media thickening and early atherosclerotic plaque formation. This adaptive response occurs at the site of the lesion to preserve luminal area. The percent change in ED is strongly related to plaque thickness and is greatest in the more distal arteries.

Adult↗
PubMed1998

Percutaneous ultrasound guided thrombin injection: a new method for treating postcatheterization femoral pseudoaneurysms.

PURPOSE: Since its introduction in 1991, ultrasound guided compression repair of postcatheterization femoral artery pseudoaneurysms has been shown to be effective. Disadvantages of ultrasound guided compression repair include patient discomfort during compression, inability to treat noncompressible pseudoaneurysms, prolonged use of ultrasound equipment and personnel, limited success with patients being treated with anticoagulants, and some early recurrences. We conducted a prospective study to evaluate a new method of treating femoral pseudoaneurysms, percutaneous ultrasound guided thrombin injection. METHODS: Under duplex ultrasound guidance, a 22- or 25-gauge needle was percutaneously positioned within the pseudoaneurysm. Without compressing the pseudoaneurysm, 0.5 to 1 ml thrombin solution (1000 U/ml) was injected to induce thrombosis. Early in the study, the procedure was modified to allow more than one injection. After successful thrombosis, the patients were kept at rest in bed for at least 1 hour. Duplex ultrasound examination was repeated in 1 to 4 days. Distal pulses and ankle-brachial indexes were measured before and after the procedure. RESULTS: Twenty of 21 consecutive pseudoaneurysms were successfully treated with thrombin injection. Fifteen pseudoaneurysms thrombosed immediately (<20 seconds) after one injection. The other five had partial thrombosis after one injection and complete thrombosis immediately after a second injection. The one failure occurred in a patient who had only one injection and then underwent subsequent ultrasound guided compression repair, which failed. No patient required sedation or analgesia during thrombin injection. There were no procedure-related complications and no recurrences. CONCLUSIONS: Percutaneous ultrasound guided thrombin injection appears to be a safe and expeditious method for treating postcatheterization femoral pseudoaneurysms. It has significant advantages with respect to ultrasound guided compression repair or surgical repair.

Adult↗
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↗