Nicos Labropoulos

Definition of venous reflux in lower-extremity veins

PURPOSE This prospective study was designed to determine the upper limits of normal for duration and maximum velocity of retrograde flow (RF) in lower extremity veins. METHODS Eighty limbs in 40 healthy subjects and 60 limbs in 45 patients with chronic venous disease were examined with duplex scanning in the standing and supine positions. Each limb was assessed for reflux at 16 venous sites, including the common femoral, deep femoral, and proximal and distal femoral veins; proximal and distal popliteal veins; gastrocnemial vein; anterior and posterior tibial veins; peroneal vein; greater saphenous vein, at the saphenofemoral junction, thigh, upper calf, and lower calf; and lesser saphenous vein, at the saphenopopliteal junction and mid-calf. Perforator veins along the course of these veins were also assessed. In the healthy volunteers, 1553 vein segments were assessed, including 480 superficial vein segments, 800 deep vein segments, and 273 perforator vein segments; and in the patients, 1272 vein segments were assessed, including 360 superficial vein segments, 600 deep vein segments, and 312 perforator vein segments. Detection and measurement of reflux were performed at duplex scanning. Standard pneumatic cuff compression pressure was used to elicit reflux. Duration of RF and peak vein velocity were measured immediately after release of compression. RESULTS Duration of RF in the superficial veins ranged from 0 to 2400 ms (mean, 210 ms), and was less than 500 ms in 96.7% of these veins. In the perforator veins, regardless of location, outward flow ranged from 0 to 760 ms (mean, 170 ms), and was less than 350 ms in 97% of these veins. In the deep veins, RF ranged from 0 to 2600 ms. Mean RF in the deep femoral veins and calf veins was 190 ms, and was less than 500 ms in 97.6% of these veins. In the femoropopliteal veins, mean RF was 390 ms, and ranged from 510 to 2600 ms in 21 of 400 segments; however, RF was less than 990 ms in 99% of these veins. Duration of RF was significantly longer in all three veins systems in patients (P <.0001 for all comparisons). With a cutoff value of more than 1000 ms rather than more than 500 ms, prevalence of abnormal RF in the femoropopliteal veins was significantly reduced, from 29% to 18% (P =.002). Thirty-seven vein segments (2.4%) had RF greater than 500 ms in the supine position, compared with less than 500 ms in 22 of these vein segments (59%) in the standing position. Of the 48 vein segments (3.1%) with RF greater than 500 ms in the standing position, RF was less than 500 ms in 6 of these vein segments (13%) in the supine position. Similar observations were noted in patient veins. There was no association between RF and peak vein velocity. Peak vein velocity had no significance in determining reflux. CONCLUSIONS The cutoff value for reflux in the superficial and deep calf veins is greater than 500 ms. However, the reflux cutoff value for the femoropopliteal veins should be greater than 1000 ms. Outward flow in the perforating veins should be considered abnormal at greater than 350 ms. Reflux testing should be performed with the patient standing.

Classification and Grading of Chronic Venous Disease in the Lower Limbs-A Consensus Statement-

Classification and grading of chronic venous disease in the lower limbs : A consensus statement

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.

EXPANDED INDICATIONS FOR ULTRASOUND-GUIDED THROMBIN INJECTION OF PSEUDOANEURYSMS

PURPOSE We previously reported preliminary data on a new procedure that we developed for the treatment of femoral pseudoaneurysms after catheterization. This study presents our current results of percutaneous ultrasound-guided thrombin injection for treating pseudoaneurysms that arise from various locations and causes. METHODS Between February 1996 and May 1999, we performed thrombin injection of 83 pseudoaneurysms in 82 patients. There were 74 femoral pseudoaneurysms: 60 from cardiac catheterization (36 interventional), seven from peripheral arteriography (four interventional), five from intra-aortic balloon pumps, and two from dialysis catheters. There were nine other pseudoaneurysms: five brachial (two cardiac catheterization, two gunshot wounds, one after removal of an infected arteriovenous graft), one subclavian (central venous catheter insertion), one radial (arterial line), and one distal superficial femoral and one posterior tibial (both after blunt trauma). Twenty-nine pseudo-aneurysms were injected while on therapeutic anticoagulation. Patients underwent repeat ultrasound examination within 5 days and after 4 weeks. RESULTS Eighty-two of 83 pseudoaneurysms had initial successful treatment by this technique, including 28 of 29 in patients who were undergoing anticoagulation therapy. The only complication was thrombosis of a distal brachial artery, which resolved spontaneously. There were early recurrences in seven patients: four patients underwent successful reinjection; reinjection failed in two patients, who underwent surgical repair; and one patient had spontaneous thrombosis on follow-up. After 4 weeks, ultrasound examinations were completely normal or showed some residual hematoma, and there were no recurrent pseudoaneurysms. CONCLUSION Ultrasound-guided thrombin injection of pseudoaneurysms has excellent results, which support its widespread use as the primary treatment for this common problem.

Superficial venous insufficiency: Correlation of anatomic extent of reflux with clinical symptoms and signs

PURPOSE The aim of this study was to assess the distribution and extent of valvular incompetence in patients with reflux confined to the superficial venous system and correlate the extent of such reflux with clinical symptoms and signs. METHODS Two hundred fifty-five limbs of 217 patients with superficial venous insufficiency and normal perforating and deep veins were examined with color-flow duplex imaging. One hundred twenty-three limbs (48.2%) of 102 patients had reflux confined to the long saphenous system, 83 limbs (32.6%) of 72 patients had reflux confined to the the short saphenous system, and 49 limbs (19.2%) of 43 patients had reflux in both long and short saphenous systems. RESULTS In the long saphenous system the commonest pattern of reflux was that which extended throughout the length of long saphenous vein (LSV) (47%). Ache, swelling, and skin changes were common in the presence of below knee reflux irrespective whether the thigh segment was involved. Ulceration (8%) was found only in limbs with reflux extending throughout the length of LSV. In the short saphenous system the most common pattern of reflux extended throughout the length of short saphenous vein (SSV) (57%) without involvement of Giacomini or gastrocnemial veins. Ache and swelling were present in 62% and 72% of the limbs, but this incidence was not related to the extent of reflux. Swelling, skin changes, and ulceration occurred only when the whole of the SSV was involved. In the limbs with reflux in both the long and short saphenous systems, the most common pattern of reflux extended throughout the length of both systems (45%). In these limbs the incidence of swelling was 80%. The incidence of skin changes went from 44% when the below-knee segment of the LSV was involved to 73% when reflux occurred throughout the LSV and SSV. Ulceration (14%) was found only in the latter situation. Variable patterns of saphenogastrocnemial termination were seen. In 57.8% of the limbs SSV joined the popliteal vein just above the popliteal crease, whereas the SSV terminated in the thigh in 26.6%. CONCLUSIONS We conclude that ache, ankle edema, and skin changes in limbs with reflux confined to the superficial venous system are predominantly associated with reflux in the below-knee veins. Ulceration is found only when the whole of the LSV is involved (8%) or when reflux is extensive in both LSV and SSV (14%).

Real-time ultrasound-guided subclavian vein cannulation versus the landmark method in critical care patients: A prospective randomized study*

Objective:Subclavian vein catheterization may cause various complications. We compared the real-time ultrasound-guided subclavian vein cannulation vs. the landmark method in critical care patients. Design:Prospective randomized study. Setting:Medical intensive care unit of a tertiary medical center. Patients:Four hundred sixty-three mechanically ventilated patients enrolled in a randomized controlled ISRCTN-registered trial (ISRCTN-61258470). Interventions:We compared the ultrasound-guided subclavian vein cannulation (200 patients) vs. the landmark method (201 patients) using an infraclavicular needle insertion point in all cases. Catheterization was performed under nonemergency conditions in the intensive care unit. Randomization was performed by means of a computer-generated random-numbers table and patients were stratified with regard to age, gender, and body mass index. Measurements and Main Results:No significant differences in the presence of risk factors for difficult cannulation between the two groups of patients were recorded. Subclavian vein cannulation was achieved in 100% of patients in the ultrasound group as compared with 87.5% in the landmark one (p < .05). Average access time and number of attempts were significantly reduced in the ultrasound group of patients compared with the landmark group (p < .05). In the landmark group, artery puncture and hematoma occurred in 5.4% of patients, respectively, hemothorax in 4.4%, pneumothorax in 4.9%, brachial plexus injury in 2.9%, phrenic nerve injury in 1.5%, and cardiac tamponade in 0.5%, which were all increased compared with the ultrasound group (p < .05). Catheter misplacements did not differ between groups. In this study, the real-time ultrasound method was rated on a semiquantitative scale as technically difficult by the participating physicians. Conclusions:The present data suggested that ultrasound-guided cannulation of the subclavian vein in critical care patients is superior to the landmark method and should be the method of choice in these patients.

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.

Asymptomatic internal carotid artery stenosis and cerebrovascular risk stratification

BACKGROUND The purpose of this study was to determine the cerebrovascular risk stratification potential of baseline degree of stenosis, clinical features, and ultrasonic plaque characteristics in patients with asymptomatic internal carotid artery (ICA) stenosis. METHODS This was a prospective, multicenter, cohort study of patients undergoing medical intervention for vascular disease. Hazard ratios for ICA stenosis, clinical features, and plaque texture features associated with ipsilateral cerebrovascular or retinal ischemic (CORI) events were calculated using proportional hazards models. RESULTS A total of 1121 patients with 50% to 99% asymptomatic ICA stenosis in relation to the bulb (European Carotid Surgery Trial [ECST] method) were followed-up for 6 to 96 months (mean, 48). A total of 130 ipsilateral CORI events occurred. Severity of stenosis, age, systolic blood pressure, increased serum creatinine, smoking history of more than 10 pack-years, history of contralateral transient ischemic attacks (TIAs) or stroke, low grayscale median (GSM), increased plaque area, plaque types 1, 2, and 3, and the presence of discrete white areas (DWAs) without acoustic shadowing were associated with increased risk. Receiver operating characteristic (ROC) curves were constructed for predicted risk versus observed CORI events as a measure of model validity. The areas under the ROC curves for a model of stenosis alone, a model of stenosis combined with clinical features and a model of stenosis combined with clinical, and plaque features were 0.59 (95% confidence interval [CI] 0.54-0.64), 0.66 (0.62-0.72), and 0.82 (0.78-0.86), respectively. In the last model, stenosis, history of contralateral TIAs or stroke, GSM, plaque area, and DWAs were independent predictors of ipsilateral CORI events. Combinations of these could stratify patients into different levels of risk for ipsilateral CORI and stroke, with predicted risk close to observed risk. Of the 923 patients with ≥ 70% stenosis, the predicted cumulative 5-year stroke rate was <5% in 495, 5% to 9.9% in 202, 10% to 19.9% in 142, and ≥ 20% in 84 patients. CONCLUSION Cerebrovascular risk stratification is possible using a combination of clinical and ultrasonic plaque features. These findings need to be validated in additional prospective studies of patients receiving optimal medical intervention alone.

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.

Ultrasonic carotid artery plaque structure and the risk of cerebral infarction on computed tomography

PURPOSE The North American and the European Symptomatic Carotid Endarterectomy Trial investigators reported a conclusive benefit of carotid endarterectomy for patients with symptomatic 70% to 99% internal carotid artery (ICA) stenosis. However, it has been suggested that plaque structure may be an even more important factor in producing stroke than the degree of stenosis. The aim of this study was to test the hypothesis that the ultrasonic characteristics of carotid artery plaques were closely related to symptoms and to the prevalence of cerebral infarcts on computed tomography (CT). METHODS One hundred five carotid artery plaques causing greater than 70% stenosis in the ICA in 83 consecutive patients who underwent brain CT were characterized into four ultrasonic types: echolucent plaques, predominantly echolucent plaques, predominantly echogenic plaques, and echogenic plaques. Patients with permanent neurologic deficit were excluded. RESULTS There was a significant ipsilateral association between type 1 plaques and symptomatic hemispheres (p < 0.002). Twenty-six of the 105 cerebral hemispheres assessed by CT had infarcts. There was an increased incidence of brain infarcts in type I plaques (37%) compared with 18% in types II, III, and IV combined (p < 0.02). CONCLUSION Our results support the hypothesis that echolucent plaques are more frequently associated with symptoms and cerebral infarctions and provide further evidence that these plaques are unstable and tend to embolize. Studies on the natural history of asymptomatic carotid artery stenosis should investigate whether plaque characterization could identify a high-risk group.