Post-thrombotic syndrome in children: a systematic review of frequency of occurrence, validity of outcome measures, and prognostic factors

Background

Post-thrombotic syndrome is a manifestation of chronic venous insufficiency following deep venous thrombosis. This systematic review was conducted to critically evaluate pediatric evidence on frequency of occurrence, validity of outcome measures, and prognostic indicators of post-thrombotic syndrome.

Design and Methods

A comprehensive literature search of original reports revealed 19 eligible studies, totaling 977 patients with upper/lower extremity deep venous thrombosis. Calculated weighted mean frequency of post-thrombotic syndrome was 26% (95% confidence interval: 23–28%) overall, and differed significantly by prospective/non-prospective analysis and use/non-use of a standardized outcome measure.

Results

Standardized post-thrombotic syndrome outcome measures included an adaptation of the Villalta scale, the Clinical-Etiologic-Anatomic-Pathologic classification, and the Manco-Johnson instrument. Data on validity were reported only for the Manco-Johnson instrument. No publications on post-thrombotic syndrome-related quality of life outcomes were identified. Candidate prognostic factors for post-thrombotic syndrome in prospective studies included use/non-use of thrombolysis and plasma levels of factor VIII activity and D-dimer.

Conclusions

Given that affected children must endure chronic sequelae for many decades, it is imperative that future collaborative pediatric prospective cohort studies and trials assess as key objectives and outcomes the incidence, severity, prognostic indicators, and health impact of post-thrombotic syndrome, using validated measures.     

The post-thrombotic syndrome

One of every three patients with deep-vein thrombosis of the lower extremities will develop, within 5 years, post-thrombotic sequelae that vary from minor signs to severe manifestations such as chronic pain, intractable edema, and leg ulceration. The post-thrombotic syndrome (PTS) develops as a result of the combination of venous hypertension due to persistent outflow obstruction or valvular incompetence and abnormal microvasculature or lymphatic function. Among factors potentially related to the development of PTS, recurrent ipsilateral thrombosis plays a major role. Whether the extent and the location of the initial thrombosis are associated with the development of PTS is still controversial. The diagnosis of PTS can be accepted on clinical grounds for patients with a history of venous thrombosis. The combination of a standardized clinical evaluation with the results of compression ultrasonography and Doppler ultrasonography helps diagnose or exclude a previous proximal-vein thrombosis. Prevention of recurrent thrombosis and use of compression elastic stockings are the cornerstones of PTS prevention. The management of this condition is demanding and often frustrating. Although several surgical procedures have been tested, conservative treatment is largely preferable, as more than 50% of patients either remain stable or improve during long-term follow-up, if carefully supervised and instructed to wear proper elastic stockings. Clinical presentation helps predict the prognosis, being the outcome of patients who refer with initially severe manifestations more favorable than that of patients whose symptoms progressively deteriorate over time.     

Venous haemodynamics of the upper extremity after subclavian vein thrombosis

Late post-thrombotic complaints after subclavian vein thrombosis are reported with highly varying frequencies (8-80% severe disability). The therapeutic approach depends partly on this frequency. With the aim to evaluate late sequelae a questionnaire was answered by 26 patients with arm-shoulder symptoms leading to arm phlebography, but where the examination did not reveal any thrombi. 65% had remaining symptoms 2-9 years after the examination. 3 had to change profession. 36 patients with phlebographically shown subclavian vein thrombosis answered the same questionnaire. Only 9 (25%) had remaining symptoms and in 4 it was classified as mild, in 4 as moderate and only in 1 patient as severe leading to change of profession. Venous haemodynamics in the upper extremity were also studied in 3 groups of patients; I) healthy volunteers (n = 16 arms), II) patients with arm-shoulder disabilities with negative arm phlebography (n = 7 disabled arms, n = 7 non-disabled arms), III) patients with phlebographically verified subclavian vein thrombi (n = 10 arms with DVT, n = 8 arms without DVT). Strain gauge plethysmography was used measuring venous capacity and maximal venous outflow. Venous pressure measurements were made both with the arms in a resting position and in a military position with and without work-load. Repeat phlebography of arms with symptoms were made. Maximal venous outflow was significantly lower in arms with previous subclavian vein thrombi (p less than 0.05) and venous pressure measurements with the arm in military position was significantly higher in those arms. However, no correlation between these measurements and the degree of arm disability was noted.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term low-molecular-weight heparin and the post-thrombotic syndrome: a systematic review

Objective

Post-thrombotic syndrome causes considerable morbidity. The Home-LITE study showed a lower incidence of post-thrombotic syndrome and venous ulcers after 3 months of treating deep vein thrombosis with the low-molecular-weight heparin tinzaparin versus oral anticoagulation. This systematic review examined whether long-term treatment of deep vein thrombosis using low-molecular-weight heparin, rather than oral anticoagulation, reduces development of post-thrombotic syndrome.

Methods

We identified 9 articles comparing treatment of deep vein thrombosis using long-term low-molecular-weight heparin with any comparator, which reported outcomes relevant to the post-thrombotic syndrome assessed ≥ 3 months post-deep vein thrombosis.

Results

Pooled analysis of 2 studies yielded an 87% risk reduction with low-molecular-weight heparin in the incidence of venous ulcers at ≥ 3 months (P = .019). One study showed an overall odds ratio of 0.77 (P = .001) favoring low-molecular-weight heparin for the presence of 8 patient-reported post-thrombotic syndrome signs and symptoms. Pooled analysis of 5 studies showed a risk ratio for low-molecular-weight heparin versus oral anticoagulation of 0.66 (P < .0001) for complete recanalization of thrombosed veins.

Conclusion

These results support the lower incidence of post-thrombotic syndrome and venous ulcers observed in Home-LITE. Long-term treatment with low-molecular-weight heparin rather than oral anticoagulation after a deep vein thrombosis may reduce or prevent development of signs and symptoms associated with post-thrombotic syndrome. Post-thrombotic syndrome and associated acute ulcers may develop more rapidly after deep vein thrombosis than previously recognized.     

Axillary-subclavian venous thrombosis. Therapeutic management

24 cases of axillary-subclavian venous thrombosis were studied according to the etiology: "intrinsic" thrombosis secondary to alteration of the endothelium (7 cases), "extrinsic" thrombosis secondary to compression at the level of the thoracic outlet (4 cases), "combined" thrombosis following a complex treatment of breast cancer (3 cases). The frequency of these thromboses, undoubtedly underestimated, seems low as compared to that of venous thromboses of the lower extremities. The frequency of pulmonary emboli is 8%. The treatment is limited to anticoagulants in case of intrinsic or combined thrombosis. In the third type, decompressive surgery is necessary, especially if there are abnormalities of the cervico-dorsal junction or associated neurological or arterial disorders.     

Rivaroxaban Versus Warfarin and Risk of Post-Thrombotic Syndrome Among Patients with Venous Thromboembolism

Background

The effectiveness of rivaroxaban to reduce post-thrombotic syndrome in patients with venous thromboembolism is largely unknown. We compared rates of post-thrombotic syndrome in patients given rivaroxaban versus warfarin in a cohort of patients with incident venous thromboembolism receiving routine clinical care.

Assessment of the patency of deep leg veins with duplex.

To evaluate the accuracy of venous duplex, results obtained in 101 patients are compared with venography. A first group consisted of 48 patients with clinically suspected deep vein thrombosis. In 30 of them a positive duplex scan was obtained and all had subsequently a positive venography. Eighteen patients with a normal duplex scan had a normal venography. Another group of 53 patients were tested preoperatively for varicose vein surgery. No obstruction of the venous system was withheld with duplex but 3 patients had an old thrombosis on venography. Thus duplex is a highly reliable method to detect proximal thrombosis in clinically suspected patients but detection of late sequelae of thrombosis may be more difficult.     

Assessment of acute and old deep venous thrombosis in upper extremity by venous strain gauge plethysmography.

The purposes of this study were to evaluate the efficiency of occlusion strain gauge plethysmography in the diagnosis of symptomatic deep venous thrombosis in upper extremities, to compare early (one month) and late clinical evolution (many years) to plethysmography data and, finally, to set up normal and pathological values. Four groups of patients were tested. Sixteen patients with confirmed acute thrombosis, 6 patients with unconfirmed thrombosis, 15 with an old thrombosis (mean follow-up: 7 years) as well as 15 healthy volunteers. The outflows measurements were significantly lowered (p less than 0.05) in the arms with acute thrombosis compared to the contralateral arms, to the affected arms of patients with thrombosis excluded and to both volunteers' arms. Pathological values for the different outflow parameters could be defined as follows: Maximum venous output less than 110 ml/100 ml/minute, Outflow after 3 seconds less than 1.2 ml/100 ml, Strandness index less than 0.16. On month after the acute episode we found a good correlation between the usually favourable clinical evolution and venous haemodynamics assessed by plethysmography. The mild late post-thrombotic syndrome of most patients with an old thrombosis was not well demonstrated by plethysmography.     

Effect of postthrombotic syndrome on health-related quality of life after deep venous thrombosis

BACKGROUND: Postthrombotic syndrome (PTS) is a frequent chronic complication of deep venous thrombosis, yet its impact on health-related quality of life has not been well characterized. We compared generic and venous disease-specific quality of life in patients with and without PTS, and assessed whether quality of life correlated with severity of PTS. METHODS: Subjects with previous deep venous thrombosis were participants in a study of the effects of exercise after deep venous thrombosis. We ascertained PTS and its severity using a validated clinical scale. Subjects completed generic (the 36-Item Short-Form Health Survey) and disease-specific (Venous Insufficiency Epidemiologic and Economic Study quality-of-life questionnaire [VEINES-QOL] and its validated subscale of 10 items on venous symptoms [VEINES-Sym]) quality-of-life measures. Age- and sex-adjusted mean quality-of-life scores were compared in patients with and without PTS, and by severity of PTS. RESULTS: Of the 41 subjects (mean age, 51.2 years), 19 (46%) had PTS. Subjects with PTS had significantly worse disease-specific quality-of-life scores than those without PTS (mean +/- SD VEINES-QOL score, 44.5 +/- 11.6 vs 54.8 +/- 5.4, respectively [P<.001]; mean +/- SD VEINES-Sym score, 45.6 +/- 11.4 vs 54.1 +/- 6.7, respectively [P =.003]), which worsened significantly with increasing severity of PTS. We found no differences in generic quality-of-life scores between subject groups. CONCLUSIONS: Postthrombotic syndrome has a significant impact on disease-specific quality of life that may not be captured by generic quality-of-life measures. Patient-based quality-of-life measures correlated well with physician-assessed PTS. Further research is indicated to assess the value of including quality of life as a routine measure of outcome in clinical studies of patients with deep venous thrombosis and PTS.     

Axillary and subclavian venous thrombosis. Prognosis and treatment

To clarify the prognosis of axillary and subclavian deep venous thrombosis and to determine which clinical factors influence its sequelae, we systematically reviewed the English-language literature published on this subject since 1950. Seventy-one case reports and 17 case series describing a total of 329 patients met our inclusion criteria for detailed review. There were major deficiencies in the quality, as well as quantity, of the available clinical data: few patients were enrolled at axillary and subclavian deep venous thrombosis inception, and outcome assessments were susceptible to bias and based on insensitive diagnostic tests. Posttreatment symptoms were reported in 34% of cases, pulmonary embolism in 9.4% (one half documented by lung scan or angiography), and death in 1.2% (three of four deaths due to pulmonary emboli). These complications occurred regardless of etiologic category (spontaneous, catheter related, or miscellaneous). Thrombolytic agents and surgery, in addition to anticoagulation, were often used to treat axillary and subclavian deep venous thrombosis, but there were no controlled trials to support any one approach. Until such trials are performed, therapy should be based on the anticoagulation regimens proved to be effective for deep venous thrombosis of the lower extremity. In selected patients, thrombolytic therapy and surgery may have important roles.     

Long-term follow-up of patients with suspected deep vein thrombosis of the upper extremity: survival, risk factors and post-thrombotic syndrome

BACKGROUND: The outcome of upper extremity thrombosis in terms of morbidity, mortality and arm functionality is virtually unknown. We investigated mortality, risk factors, recurrent thrombosis and post-thrombotic syndrome (PTS) in patients with suspected upper extremity thrombosis. METHODS: Consecutive patients suspected of having deep vein thrombosis (DVT) of the upper extremity were followed for up to 53 months (mean 21 months). Venography and/or ultrasonography was used for diagnosis. Risk factors were identified from history and thrombophilia laboratory screening. PTS was assessed using a scoring system. Death, recurrent thrombosis and PTS were primary outcome measures. RESULTS: DVT of the upper extremity was diagnosed in 50 of 116 consecutive patients (43%). Malignancy and/or central venous lines were present in 37 of 50 (74%) patients with thrombosis. Inherited thrombophilia was diagnosed in 6 of 30 (20%) and 4 of 33 (12%) of the investigated patients with and without thrombosis, respectively (not significant). Twenty-five patients (50%) with thrombosis died during the follow-up period; this was associated with cancer in 84% of the deaths. Recurrent thrombosis was observed in four patients (8%) during follow-up. Symptoms of PTS were present in 4 of 22 patients (18%) with thrombosis and in 14 of 36 patients (39%) in whom thrombosis was excluded. CONCLUSIONS: Malignancy and central venous lines are major risk factors of upper extremity thrombosis. Thrombophilia seems to be unrelated to the presence or absence of upper extremity thrombosis. Thrombosis in combination with malignancy predicts poor survival. A scoring system can be used to assess the severity of PTS, but it does not discriminate PTS from other causes of arm complaints.     

Correlation between ammonia levels and the severity of hepatic encephalopathy

PURPOSE: Because the correlation between ammonia levels and the severity of hepatic encephalopathy remains controversial, we prospectively evaluated the correlation in 121 consecutive patients with cirrhosis. METHODS: The diagnosis of hepatic encephalopathy was based on clinical criteria, and the severity of hepatic encephalopathy was based on the West Haven Criteria for grading of mental status. Arterial and venous blood samples were obtained from each patient. Four types of ammonia measurements were analyzed: arterial and venous total ammonia, and arterial and venous partial pressure of ammonia. Spearman rank correlations (r(s)) were calculated. RESULTS: Of the 121 patients, 30 (25%) had grade 0 encephalopathy (no signs or symptoms), 27 (22%) had grade 1, 23 (19%) had grade 2, 28 (23%) had grade 3, and 13 (11%) had grade 4 (the most severe signs and symptoms). Each of the four measures of ammonia increased with the severity of hepatic encephalopathy: arterial total ammonia (r(s) = 0.61, P < or = 0.001), venous total ammonia (r(s) = 0.56, P < or = 0.001), arterial partial pressure of ammonia (r(s) = 0.55, P < or = 0.001), and venous partial pressure of ammonia (r(s) = 0.52, P < or = 0.001). CONCLUSION: Ammonia levels correlate with the severity of hepatic encephalopathy. Venous sampling is adequate for ammonia measurement. There appears to be no additional advantage of measuring the partial pressure of ammonia compared with total ammonia levels.     

Patterns of venous reflux in limbs with venous ulcers. Implications for treatment.

AIM: To investigate the anatomic distribution of vein reflux in limbs with healed or active ulcers (CEAP V and VI). METHODS: Sixty limbs (58 patients) belonging to CEAP classes V and VI were identified from 798 limbs (519 patients) with ultrasonically proven chronic venous insufficiency (CVI). Age, gender, duration of the venous ulcer, and history of deep venous thrombosis were correlated to the anatomic distribution of the venous reflux. RESULTS: The prevalence of active or healed ulcers in limbs with CVI was 7.5%. Among 60 limbs with ulcers, primary CVI was present in 34 (56.7%) and post-thrombotic CVI in 26 limbs (43.3%). No difference in age and gender was found between the 2 groups (p=0.2 and p=0.8, respectively). However, the duration of the ulcer was longer in limbs with post-thrombotic CVI (p<0.05). The prevalence of perforator reflux was 41.2% (14/34) in limbs with primary CVI and 38.5% (10/26) in limbs with post-thrombotic CVI (p=0.8). Superficial venous insufficiency, with or without perforating vein reflux, was the commonest pattern in limbs with primary CVI; it was rare in limbs with post-thrombotic CVI (22/34 or 64.7% vs 2/26 or 7.7%, p<0.01). Deep vein insufficiency was present in 35.3% (12/34) of the limbs with primary CVI and in 92.3% (24/26) of the limbs with post-thrombotic CVI (p<0.01). CONCLUSION: Superficial venous insufficiency, with or without perforating vein reflux, was the commonest pattern in limbs with primary CVI, whereas, deep venous insufficiency was present in most of the limbs with post-thrombotic CVI. The prevalence of perforating vein reflux was comparable in both settings. Thus, elimination of superficial reflux is expected to result in ulcer healing of most limbs with primary CVI, whereas, the value of such treatment in post-thrombotic limbs is not clear.     

Venography in axillary-subclavian vein thrombosis.

Nineteen patients with 20 axillary-subclavian vein thromboses were examined by venography. In 70% the axillary and subclavian veins were involved in continuity. The innominate vein was seldom involved, although demonstration of this was difficult. In 50% of the patients the thrombosis was a secondary phenomenon associated with either breast carcinoma, central venous pressure lines, heroin addiction, or cervical rib.     

Evaluation of clinical signs and symptoms in active deep venous thrombosis of the calf

The diagnostic value of 16 signs and symptoms of active deep venous thrombosis of the calf (ADVTC) is analysed. Thirty-nine patients suspected of ADVTC were examined clinically using 16 symptoms and signs, the 125I-fibrinogen uptake test and X-ray phlebography. Active thrombosis was confirmed in 19 patients, in 20 patients the diagnosis of post-thrombotic syndrome was established. The pattern recognition procedure, carried out with the aid of 16 symptoms and signs only by a computer, was able to differentiate both conditions with 95% sensitivity and 90% specificity. The data do not comprise unexamined asymptomatic ADVTC, which type of ADVTC it is impossible to detect. The most important signs for recognition of ADVTC appeared to be (in the order of importance): painful calf pressure, a positive Meyer sign, asymmetrical oedema and a painful Lowenberg test between 80 and 139 mmHg, i.e. a painful calf and asymmetrical oedema.     

Subfascial endoscopic perforator vein surgery: indications and results.

Subfascial endoscopic perforator surgery (SEPS) is a new, minimally invasive technique performed in patients with advanced chronic venous insufficiency. The objective of the operation is to interrupt incompetent medial calf perforating veins to decrease venous reflux and reduce ambulatory venous hypertension in critical areas above the ankle where venous ulcers most frequently develop. Patients with stasis skin changes and healed or active venous ulcerations are potential candidates for the operation. Preoperative evaluation is performed with duplex scanning of the superficial, deep and perforator system, to diagnose both obstruction and valvular incompetence. Results of the North American SEPS Registry (NASEPS) as well as experience in several individual centers confirmed that the operation has significantly fewer wound complications than the classic open surgical techniques, and that rapid ulcer healing can be achieved. At the Mayo Clinic an ulcer recurrence rate of 12% was observed, with recurrence significantly more frequent in post-thrombotic limbs than in patients with primary venous valvular incompetence. The NASEPS Registry report confirmed a 2-year cumulative ulcer recurrence rate of 28%; ulcer recurrence was significantly more frequent in post-thrombotic limbs, especially in those with deep venous obstruction. SEPS is a new, low-risk, outpatient procedure that effectively decreases perforator reflux in patients with venous ulcerations, and should be added to our armamentarium to treat patients with advanced chronic venous disease. Long-term prospective and randomized studies are, however, still required to provide level I evidence of late efficacy.     

Valve repair at the level of the sub-inguinal deep venous plexus. Gadget technique or efficacious surgery?]

Between 1988 and 1990, the authors performed 35 valvuloplasties for major reflux syndrome involving the sub-inguinal deep venous system. Twenty two patients with a mean follow-up period of 23 months (1 year--3 years) were reviewed clinically and hemodynamically. Only one of the 10 patients with a chronic ulcer had developed a recurrence. This concerned the only postoperative thrombosis seen in this series. Results from a hemodynamic standpoint were as follows: Reflux evaluated preoperatively was Kistner type 4 with a popliteal venous reflux index (VRI) with a mean grade of 1.1. Postoperative evaluation (Duplex-Scan) showed the absence of reflux below the valvuloplasty in 86 p. cent of cases and VRI was normalised (less than 0.50) to the same extent. Mean venous filling time (PPG, peripheral pressure gradient measurement) after application of a supra-malleolar tourniquet was 8" (-8n + 4) preoperatively. It became normal in 13 patients and improved in 8 (mean of 82 p. cent). The results of valvuloplasty in this series confirm those published by other teams. They are notably superior to those offered by transposition and transplantation procedures. Unfortunately, this effective technique can only rarely be used in post-thrombotic syndromes and is useful essentially in Primary Deep Valve Insufficiency.     

Predictors of venous obstruction following pacemaker or implantable cardioverter-defibrillator implantation: a contrast venographic study on 100 patients admitted for generator change, lead revision, or device upgrade.

AIM: Venous obstruction following transvenous device implantation rarely cause immediate clinical problems. When lead revision or device upgrade is indicated, venous obstruction become a significant challenge. The aim of this study was to determine the predictors of venous obstruction after transvenous device implantation, and to asess likely effects of antiplatelet/anticoagulant drugs in preventing venous thrombosis. METHODS AND RESULTS: Between March 2005 and July 2006, contrast venography was performed in 100 patients who were candidates for generator change, lead revision, or device upgrade. Vessel patency was graded as either completely obstructed, partially obstructed (>70%), or patent. The incidence of venous obstruction was 26%, with 9% of patients having total obstruction and 17% of patients exhibiting partial obstruction. No statistically significant differences between obstructed and non-obstructed patients were seen for age, sex, indication for device implantation, atrial fibrillation, cardiothoracic ratio, insulation material, operative technique, device type, and manufacturer (all Ps > 0.05). In a univariate analysis, multiple leads (P = 0.033), and presence of dilated cardiomyopathy (P = 0.036) were associated with higher risk of venous obstruction, whereas anticoagulant/antiplatelet therapy (P = 0.047) significantly reduced incidence of venous obstruction. Multivariate logistic regression analysis showed that only number of the leads (P = 0.039, OR: 2.22, and 95% CI: 1.03-4.76) and antiplatelet/anticoagulant therapy (P = 0.044, OR: 2.79, and 95% CI: 0.98-7.96) were predictors of venous obstruction. CONCLUSION: Total or partial obstruction of the access veins occurs relatively frequently after pacemaker or ICD implantation. Multiple pacing or ICD leads are associated with an increased risk of venous obstruction, whereas antiplatelet/anticoagulant therapy appears to have a preventive effect on development of access vein thrombosis.     

Home Therapy of Venous Thrombosis with Long-term LMWH versus Usual Care: Patient Satisfaction and Post-thrombotic Syndrome

Purpose

Home-LITE compared long-term treatment at home with tinzaparin or usual care in terms of efficacy, safety, patients' treatment satisfaction, incidence of post-thrombotic syndrome, and associated venous leg ulcers.

Methods

This multicenter, randomized, controlled trial enrolled 480 patients with documented, acute, proximal deep vein thrombosis. Patients received tinzaparin 175 IU/kg subcutaneously once daily for 12 weeks, or tinzaparin for ≥5 days plus oral warfarin, commenced on day 1, international normalized ratio-adjusted, and continued for ≥12 weeks (“usual care”). Patients received 1 in-clinic injection, then home treatment.

Results

The rate of recurrent venous thromboembolism at 12 weeks was 3.3% in both groups (absolute difference 0%; 95% confidence interval −3.2-3.2), and at 1 year was 10.4%/8.3% in the tinzaparin/usual-care groups, respectively (difference 2.1%; 95% confidence interval −3.1-7.3). There were no between-group differences in deaths at 12 weeks or 1 year, or bleeding at 12 weeks. Patients in the tinzaparin group expressed significantly greater treatment satisfaction (P = .0024), particularly regarding freedom from the inconvenience of blood monitoring; were less likely to report signs/symptoms of post-thrombotic syndrome (individual odds ratios 0.66 to 0.91, overall odds ratio 0.77, P = .001); and reported fewer leg ulcers at 12 weeks: 1 (0.5%) versus 8 (4.1%) (P = .02) with usual care.

Conclusions

Long-term home treatment with tinzaparin or usual care resulted in similar rates of recurrent venous thromboembolism, death, and bleeding. The significantly lower incidence of post-thrombotic syndrome and leg ulcers observed in the tinzaparin group is a potentially important benefit and deserves further study.     

Clinical and Ultrasonographic Evaluation of Lower-extremity Vein Thrombosis in Behcet Syndrome: An Observational Study

Vascular involvement can be seen in up to 40% of patients with Behcet syndrome (BS), the lower-extremity vein thrombosis (LEVT) being the most common type. The aim of the current study was to compare venous Doppler findings and clinical features between BS patients with LEVT and control patients diagnosed as having LEVT due to other causes.All consecutive 78 patients (71 men, 7 women; mean age 38.6 ± 10.3 years) with LEVT due to BS and 50 control patients (29 men, 21 women; mean age 42.0 ± 12.5 years) who had LEVT due to other causes, or idiopathic, were studied with the help of a Doppler ultrasonography after a detailed clinical examination. Patterns of venous disease were identified by cluster analyses. Clinical features of chronic venous disease were assessed using 2 classification systems. Venous claudication was also assessed.Patients with BS were more likely to be men, had significantly earlier age of onset of thrombosis, and were treated mainly with immunosuppressives and less frequently with anticoagulants. Furthermore, they had significantly more bilateral involvement, less complete recanalization, and more frequent collateral formation. While control patients had a disorganized pattern of venous involvement, BS patients had a contiguous and symmetric pattern, involving all deep and superficial veins of the lower extremities, with less affinity for crural veins. Clinical assessment, as measured by the 2 classification systems, also indicated a more severe disease among the BS patients. In line, 51% of the BS patients suffered from severe post-thrombotic syndrome (PTS) and 32% from venous claudication, whereas these were present in 8% and 12%, respectively, among the controls. Among BS patients, a longer duration of thrombosis, bilateral femoral vein involvement, and using no anticoagulation along with immunosuppressive treatment when first diagnosed were found to be associated independently with severe PTS.Lower-extremity vein thrombosis associated with BS, when compared to LEVT due to other causes, had distinctive demographic and ultrasonographic characteristics, and had clinically a more severe disease course.