Late clinical and hemodynamic sequelae of isolated calf vein thrombosis

Central Venous Catheter as a Novel Approach to Postoperative Thrombolysis in Patients with Acute Iliofemoral Deep Venous Thrombosis

BACKGROUND AND AIMS

Percutaneous mechanical thrombectomy (PMT) along with postoperative thrombolysis (POT) has been the standard treatment for acute iliofemoral deep venous thrombosis (IFDVT). However, commonly used catheter directed thrombolysis (CDT) approaches for POT carry certain disadvantages, including the need for a sheath, inferior comfortability, and catheter-related complications. Therefore, we propose a new simplified method of POT using a central venous catheter (CVC).

METHODS

The retrospective study analyzed patients with IFDVT who underwent POT using CVC from January 2020 to August 2021. The treatment modalities included filter placement, thrombus removal, iliac vein obstruction release, postoperative CVC thrombolysis, filter retrieval, and adequate full course anticoagulation.

RESULTS

A total of 39 patients were included in this retrospective study. All patients underwent PMT surgery with a procedure success rate of 100%. In the post-PMT CVC thrombolysis, the puncture sites were located in the below-knee vein, including 58.97% in the peroneal vein. The mean duration of CVC-directed thrombolysis was 3.69 ± 1.08 days, and the total urokinase dose was 2.27 ± 0.71 MIU. A total of 37 patients (94.87%) had successful thrombolysis with a length of hospital stay of 5.82 ± 2.21 days. During CVC-directed thrombolysis, only four minor bleeding complications occurred, two of which were indwelling catheter-related. During the 12-month follow-up period, the patency rate and post-thrombotic syndrome incidences were 97.44% and 2.56%, respectively.

CONCLUSION

Thrombolysis through a CVC is a feasible, safe, and effective POT method, and could be an alternative to the conventional CDT approach for patients with IFDVT.

Prevalence of Deep Vein Thrombosis in Low-Risk Patients After Elective Foot and Ankle Surgery

BACKGROUND:

The evidence regarding the prevalence of deep vein thrombosis (DVT) after foot and ankle surgery in elective patients that need to be 6 weeks non-weight bearing postoperatively is incomplete and has limitations.

METHODS:

The prevalence of DVT in 114 procedures involving the hindfoot and midfoot was determined using ultrasonographic surveillance at 2 and 6 weeks after surgery.

RESULTS:

The prevalence of DVT was observed to be 25.4%. The majority (68.9%) of DVTs were diagnosed at the ultrasonographic scan performed 2 weeks postoperatively. The remainder (31.1%) of DVTs were diagnosed at the 6-week postoperative ultrasonographic scan. At least 75% of the patients who had early and late DVT had no clinical symptoms or signs of DVT. The prevalence of DVT in clinically detectable patients was 6%. The average age of patients with early DVT was 62.2 years, significantly higher compared to those who had no DVT. The mean tourniquet time for patients with early DVT was 68.1 minutes, significantly higher compared to those without DVT. All DVTs detected were distal to the popliteal vein.

CONCLUSIONS:

The prevalence of clinically silent DVT was significantly higher than was previously thought. We believe this increased rate is directly attributable to the use of ultrasonographic surveillance postsurgery both at 2 and 6 weeks. The risk of DVT continued after the 2-week visit, and 30% of the DVTs were detected at the ultrasonographic scan at 6 weeks.

LEVEL OF EVIDENCE:

Level II, prospective cohort.

Low molecular weight heparin for prevention of venous thromboembolism in patients with lower-limb immobilization

BACKGROUND

Immobilization of the lower limb is a risk factor for venous thromboembolism (VTE). Low molecular weight heparins (LMWHs) are anticoagulants, which might be used in adult patients with lower-limb immobilization to prevent deep venous thrombosis (DVT) and its complications. This is an update of the review first published in 2008.

OBJECTIVES

To assess the effectiveness of low molecular weight heparin for the prevention of venous thromboembolism in patients with lower-limb immobilization in an ambulatory setting.

SEARCH METHODS

For this update, the Cochrane Vascular Information Specialist searched the Specialised Register, CENTRAL, and three trials registers (April 2017).

SELECTION CRITERIA

Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that described thromboprophylaxis by means of LMWH compared with no prophylaxis or placebo in adult patients with lower-limb immobilization. Immobilization was by means of a plaster cast or brace.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed risk of bias and extracted data. The review authors contacted the trial authors for additional information if required. Statistical analysis was carried out using Review Manager 5.

MAIN RESULTS

We included eight RCTs that fulfilled our criteria, with a total of 3680 participants. The quality of evidence, according GRADE, varied by outcome and ranged from low to moderate. We found an incidence of DVT ranging from 4.3% to 40% in patients who had a leg injury that had been immobilized in a plaster cast or a brace for at least one week, and who received no prophylaxis, or placebo. This number was significantly lower in patients who received daily subcutaneous injections of LMWH during immobilization, with event rates ranging from 0% to 37% (odds ratio (OR) 0.45, 95% confidence interval (CI) 0.33 to 0.61; with minimal evidence of heterogeneity: I² = 26%, P = 0.23; seven studies; 1676 participants, moderate-quality evidence). Comparable results were seen in the following groups of participants: patients with below-knee casts, conservatively treated patients (non-operated patients), operated patients, patients with fractures, patients with soft-tissue injuries, and patients with distal or proximal thrombosis. No clear differences were found between the LMWH and control groups for pulmonary embolism (OR 0.50, 95% CI 0.17 to 1.47; with no evidence of heterogeneity: I² = 0%, P = 0.56; five studies, 2517 participants; low-quality evidence). The studies also showed less symptomatic VTE in the LMWH groups compared with the control groups (OR 0.40, 95% CI 0.21 to 0.76; with minimal evidence of heterogeneity: I² = 16%, P = 0.31; six studies; 2924 participants; low-quality evidence). One death was reported in the included studies, but no deaths due to pulmonary embolism were reported. Complications of major adverse events were rare, with minor bleeding the main adverse events reported.

AUTHORS' CONCLUSIONS

Moderate-quality evidence showed that the use of LMWH in outpatients reduced DVT when immobilization of the lower limb was required, when compared with no prophylaxis or placebo. The quality of the evidence was reduced to moderate because of risk of selection and attrition bias in the included studies. Low-quality evidence showed no clear differences in PE between the LMWH and control groups, but less symptomatic VTE in the LMWH groups. The quality of the evidence was downgraded due to risk of bias and imprecision.

Lower-extremity venous ultrasound - past, present and future

Deep vein thrombosis is a frequent clinical concern and imaging request in the pediatric population. There has been increased awareness of deep venous thrombosis in the pediatric population and sonography is now utilized more liberally and frequently to evaluate for thrombosis in the extremities. In this review the author discusses various aspects of deep vein thrombosis in the lower extremity including the pathophysiology, background, and morbidity in children. The current ultrasound guidelines and techniques, and the controversy over treatment are discussed as well.

Treatment of Isolated Below the Knee Deep Vein Thrombosis

The natural history of isolated distal deep-vein thrombosis (IDDVT) is still uncertain, as well as the real clinical risks associated with the disease and the need for its diagnosis and treatment. While more and more IDDVTs are diagnosed in everyday clinical practice, their appropriate therapeutic management is, unfortunately, far from straightforward, and different recommendations on how patients with diagnosed IDDVT should be treated are present between expert professionals and even among international guidelines. The present article aims at briefly reviewing the issue of IDDVT therapy in general, particularly focusing on the different approaches to the treatment of the disease that have been suggested by recent guidelines, those that are currently adopted in clinical practice, and necessary future directions.

Incidence and interventions for post-thrombotic syndrome

Post-thrombotic syndrome (PTS) is a venous stress disorder that develops from long-term effects from a previous deep venous thrombosis (DVT). The morbidity associated with PTS may be significant and patients can present with edema, chronic pain, swelling, skin changes, and heaviness of the affected limb. PTS can eventually lead to a decreased quality of life and to a marked burden for the healthcare system. This article elaborates on clinical aspects of PTS including the pathophysiology, diagnostic work-up and management of the disease with a particular focus on endovascular options.

Calf muscle venous thrombosis: a review of the clinical implications and therapy

Calf muscle veins have been demonstrated to be one of the most frequent areas that develop deep venous thrombosis (DVT), both as an isolated finding and in combination with proximal DVT. Calf muscle venous thrombosis (CMVT) has been shown to be more frequently associated with localized calf tenderness, and when left untreated, a proportion tend to propagate proximally and may lead to pulmonary embolism. Imaging with duplex venous scanning is fairly sensitive in the diagnosis of CMVT. Treatment recommendations for CMVT are variable with some studies showing clear clinical benefit of anticoagulation therapy and others showing no benefit.

Low molecular weight heparin for prevention of venous thromboembolism in patients with lower-leg immobilization

BACKGROUND

Immobilization of the lower leg is associated with venous thromboembolism (VTE). Low molecular weight heparin (LMWH) is an anticoagulant treatment which might be used in adult patients with lower-leg immobilization to prevent deep venous thrombosis (DVT) and its complications. This is an update of the review first published in 2008.

OBJECTIVES

To assess the effectiveness of low molecular weight heparin for the prevention of venous thromboembolism in patients with lower-leg immobilization in an ambulant setting.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched June 2013) and CENTRAL (2013, Issue 5).

SELECTION CRITERIA

Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that described thromboprophylaxis by means of LMWH compared with no prophylaxis or placebo in adult patients with lower-leg immobilization. Immobilization was by means of a plaster cast or brace.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. The review authors contacted the trial authors for additional information if required. Statistical analysis was carried out using Review Manager (RevMan 5).

MAIN RESULTS

We included six RCTs fulfilling the above criteria with a total of 1490 patients. We found an incidence of VTE ranging from 4.3% to 40% in patients who had a leg injury that had been immobilized in a plaster cast or a brace for at least one week and who received no prophylaxis, or placebo. This number was significantly lower in patients who received daily subcutaneous injections of LMWH during immobilization (event rates ranging from 0% to 37%; odds ratio (OR) 0.49; fixed 95% confidence interval (CI) 0.34 to 0.72; with minimal evidence of heterogeneity with an I(2) of 20%, P = 0. 29). Comparable results were seen in the following subcategories: operated patients, conservatively treated patients, patients with fractures, patients with soft-tissue injuries, patients with proximal thrombosis, patients with distal thrombosis and patients with below-knee casts. Complications of major bleeding events were extremely rare (0.3%) and there were no reports of heparin-induced thrombocytopenia.

AUTHORS' CONCLUSIONS

Use of LMWH in outpatients significantly reduces VTE when immobilization of the lower leg is required.

How I treat isolated distal deep vein thrombosis (IDDVT)

Thromboses limited to infrapopliteal leg deep veins (isolated distal deep vein thrombosis [IDDVT]) are frequently diagnosed in subjects with suspected pulmonary embolism or DVT and account for one-fourth to one-half of all diagnosed leg DVTs. Despite their frequency, the natural history of IDDVTs and their real risk of thromboembolic complications are still uncertain because of the scarcity of prospective, blind, nonintervention studies. Therefore it is still debated whether they warrant diagnosis and treatment. Diagnosis is based on ultrasonographic examination, which is more operator dependent and less sensitive in distal than in proximal veins. The available data seem to support the view that most IDDVTs are self-limiting and inconsequential for patients, though in some cases they can be associated with complications and warrant diagnosis and treatment. The available guidelines for treatment of IDDVTs give different indications ranging from serial imaging of the deep veins for 2 weeks to detect and treat only in case of proximal extension, to giving oral anticoagulation in all IDDVT patients for 3 months. I review this issue, focusing on possible and suggested treatments in symptomatic IDDVT patients, and describe our current therapeutic approach to these patients.

Post-thrombotic syndrome: a clinical review

Up to half of patients with proximal deep vein thrombosis (DVT) will develop post-thrombotic syndrome (PTS) despite optimal anticoagulant therapy. PTS significantly impacts upon quality of life and has major health-economic implications. This narrative review describes the pathophysiology, risk factors, and diagnosis, prevention and treatment of PTS, to improve our understanding of the disease and guide treatment. Relevant articles were identified through systematic searches of the PubMed, EMBASE and Cochrane databases between 1966 and November 2011. Studies were included for detailed assessment if they met the following criteria: published in English, human study participants, study population aged > 18 years, and lower limb post-thrombotic syndrome. All non-systematic reviews and single patient case reports were excluded. Recurrent thrombosis, thrombus location and obesity are major risk factors, whereas the importance of gender and age remain uncertain. The diagnosis of PTS is based on clinical findings in patients with a known history of DVT. Several clinical scales have been described, with the Villalta Score gaining increasing popularity. Adequate anticoagulation and use of elastic compression stockings (ECS) following DVT can reduce the incidence of PTS. Catheter-directed thrombolysis and mechanical thrombectomy of acute DVT may preserve valvular function. Studies to date of these techniques are encouraging, and have reported improved hemodynamics and a reduced incidence of PTS. The management of established PTS is challenging. Compression therapy, aimed at reducing the underling venous hypertension, remains the mainstay of treatment. This is despite a paucity of high-quality evidence to support its use. Pharmacologic and surgical treatments have also been described, with a number of studies citing symptomatic improvement.

The Anticoagulation of Calf Thrombosis (ACT) project: study protocol for a randomized controlled trial

BACKGROUND

Half of all lower limb deep vein thrombi (DVT) in symptomatic ambulatory patients are located in the distal (calf) veins. While proximal disease warrants therapeutic anticoagulation to reduce the associated risks, distal DVT often goes untreated. However, a proportion of untreated distal disease will undoubtedly propagate or embolize. Concern also exists that untreated disease could lead to long-term post thrombotic changes. Currently, it is not possible to predict which distal thrombi will develop such complications. Whether these potential risks outweigh those associated with unrestricted anticoagulation remains unclear. The Anticoagulation of Calf Thrombosis (ACT) trial aims to compare therapeutic anticoagulation against conservative management for patients with acute symptomatic distal deep vein thrombosis.

METHODS

ACT is a pragmatic, open-label, randomized controlled trial. Adult patients diagnosed with acute distal DVT will be allocated to either therapeutic anticoagulation or conservative management. All patients will undergo 3 months of clinical and assessor blinded sonographic follow-up, followed by 2-year final review. The project will commence initially as an external pilot study, recruiting over a 16-month period at a single center to assess feasibility measures and clinical event rates. Primary outcome measures will assess feasibility endpoints. Secondary clinical outcomes will be collected to gather accurate data for the design of a definitive clinical trial and will include: (1) a composite endpoint combining thrombus propagation to the popliteal vein or above, development of symptomatic pulmonary embolism or sudden death attributable to venous thromboembolic disease; (2) the incidence of major and minor bleeding episodes; (3) the incidence of post-thrombotic leg syndrome at 2 years using a validated screening tool; and (4) the incidence of venous thromboembolism (VTE) recurrence at 2 years.

DISCUSSION

The ACT trial will explore the feasibility of comparing therapeutic anticoagulation to conservative management in acute distal DVT, within a modern cohort. We also aim to provide contemporary data on clot propagation, bleeding rates and long-term outcomes within both groups. These results will inform the conduct of a definitive study if feasibility is established.

Incidence and Risk Factors of the Post-thrombotic Syndrome

Annually 1–2 in every 1000 adults will develop a deep venous thrombosis of the lower extremity. A third to half of these patients will develop the post-thrombotic syndrome (PTS). However, predicting which patients will develop the PTS remains elusive. Ipsilateral thrombosis recurrence seems to be the most important risk factor. Moreover, residual venous occlusion and valvular reflux seem to predict PTS incidence to some degree. Laboratory parameters, including D-dimers and inflammatory markers, have shown promise in predicting development of the PTS in patients and are currently under investigation. Creating a model based on all combined risk factors and patient characteristics might aid in risk stratification in individual patients.

Evaluating the Role of Compression Stockings in Preventing Post thrombotic Syndrome: A Review of the Literature

Background. Postthrombotic syndrome (PTS) is a burdensome and costly complication of deep vein thrombosis (DVT). Up to 50% of patients with DVT will develop the disease within two years following the diagnosis of acute DVT. Various risk factors for developing PTS have been identified and different modalities have been used to prevent its development. Compression stockings have been studied for the prevention of PTS in patients diagnosed with proximal DVT. Methods. MEDLINE and EMBASE databases were searched to identify relevant original articles. Results. Several trials including two metaanalyses have examined the role of compression stockings for the prevention of PTS. Although most trials showed significant reduction in the development of PTS with the use of compression stockings, limitations in study design prevent the generalizability of the data. Two studies supported an individualized tailored duration especially in patients at low risk for developing the syndrome. A randomized double-blind placebo-controlled trial involving 800 patients is currently ongoing and may confirm the results of older studies. Conclusions. Clinical trials support the use of compression stockings in patients diagnosed with proximal DVT for the prevention of PTS.

Isolated distal deep vein thrombosis: what we know and what we are doing

Thromboses that are restricted to the infra-popliteal deep veins of the lower limbs (isolated distal deep vein thrombosis, IDDVT) are frequently diagnosed in subjects with suspected pulmonary embolism (PE; 7–10%) or DVT(4–15%), accounting for 31–56% of all diagnosed leg DVTs. Despite their frequency, IDDVTs still remain one of the most debated issues in the field of venous thromboembolism (VTE). Conflicting clinical results have resulted in differing opinions on the need to test for IDDVTs and how to treat them. Due to discordant results, the real risk of IDDVT-associated PE is not well established. IDDVTs are associated with (i) lower risk of recurrence when compared with other VTEs, and (ii) fewer late sequelae than proximal DVT. Diagnosis of IDDVT is based on ultrasound examination of all calf veins, which is more operator-dependent and less sensitive than proximal vein examination. A series of studies has shown, however, that a single complete ultrasound strategy in symptomatic patients has comparable clinical results to serial proximal ultrasound, allowing approximately 15% better DVT diagnosis. Optimal treatment of IDDVT is still controversial. Guidelines recommend anticoagulation for 12 weeks, although 6 weeks may be sufficient. There is, however, insufficient data to support the diagnosis and treatment of all IDDVTs, and the necessary criteria to identify subjects at higher risk of complication are lacking. It also seems likely that different approaches may be better for unprovoked or secondary events and for deep or muscle veins. Specifically designed and adequately powered clinical studies addressing the issue of IDDVT need to be urgently undertaken.

Duplex ultrasound screening detects high rates of deep vein thromboses in critically ill trauma patients

OBJECTIVE

American College of Chest Physician (ACCP) guidelines stratify deep venous thrombosis (DVT) risk in trauma patients based on injury pattern and pharmacologic prophylaxis. Screening is only recommended for patients with high-risk injuries who are unable to receive pharmacologic prophylaxis. However, the prevalence of lower extremity DVT (LEDVT) in trauma patients may be higher than reported in previous studies as many studies on DVT screening have not investigated calf vein DVTs (CVDVT) and have not exclusively targeted critically ill patients. Given that current ACCP guidelines recommend treatment of CVDVTs, we investigated the efficacy of duplex ultrasound (DUS) screening in critically ill trauma patients for all LEDVTs, including CVDVT, regardless of injury pattern, risk factors, or pharmacologic prophylaxis.

METHODS

Medical records of 264 intensive care unit trauma patients who received DUS screening for LEDVT were retrospectively examined for the presence of injuries conferring high risk for LEDVT, patient specific DVT risk factors, and low molecular weight heparin (LMWH) prophylaxis.

RESULTS

Forty (15.2%) patients had LEDVTs found on DUS screening, 24 (60%) were CVDVT, and 30% of all DVTs were diagnosed within 1 week of admission. Patients without high-risk injuries receiving LMWH had a 13.5% DVT rate, which did not differ significantly from the 19.7% DVT rate in high-risk injury patients not receiving LMWH (P = .667).

CONCLUSIONS

Lower extremity DVT is common in critically ill trauma patients, particularly in the first week following injury, regardless of injury pattern, DVT risk factors, or pharmacologic prophylaxis. Previous studies have underestimated DVT rates by not investigating CVDVTs and not exclusively targeting critically ill patients. We recommend early and continued DUS DVT screening of all critically ill trauma patients.

The postthrombotic syndrome

Following deep vein thrombosis (DVT), one of every two patients will develop postthrombotic syndrome (PTS), which causes remarkable consequences on the socioeconomic level. Residual thrombosis is an important predictor of PTS, and severe early symptoms, old age, obesity, improper anticoagulation, recurrent thrombosis and varicose veins are major risk factors. Diagnosis of PTS is mainly based on the clinical findings for patients with a history of DVT, while in those without it, instrumental diagnosis might help in detecting a previous DVT. Prompt administration of adequate compression elastic stockings (ECS) in patients with symptomatic DVT reduces the frequency of PTS by half. Usually, the management of an established PTS is demanding, and often discouraging. However, when carefully supervised and instructed to wear proper ECS, more than 50% of patients either remain quiescent or improve during long-term follow-up.

Current prescribing patterns of elastic compression stockings post-deep venous thrombosis

Objectives

Post-thrombotic syndrome (PTS) is a complication of deep vein thrombosis (DVT) characterized by chronic pain, swelling and heaviness, and may result in ulceration. Elastic compression stockings (ECS) worn daily after DVT appear to reduce the incidence and severity of PTS. The aims of our study were to investigate practices and perceptions of DVT patients and physicians regarding the use of ECS after DVT.

Methods

Two surveys were conducted. The first was sent to 225 staff and trainee clinicians and the second was administered to 150 DVT patients.

Results

The results demonstrated that the majority of senior staff (75%) believed that ECS were effective in preventing PTS and in managing venous symptoms. However, this was in contrast with junior trainees (21%) ( P < 0.05). This resulted in only 63% of patients being prescribed ECS post-DVT. There was a lack of consensus as regards the optimal timing of initiation of ECS, duration of therapy and compression strength. Nearly all DVT patients who were prescribed ECS purchased them, 74% wore them daily, and most (61%) reported that ECS relieved swelling and symptoms. Physicians correctly predicted the main reasons for non-compliance, but misjudged the scale of patient compliance with ECS.

Conclusions

Our findings suggest that there is a lack of consensus among doctors regarding ECS use after DVT and widespread education regarding the latest evidence of the benefit of ECS after DVT.

Do not forget the distal lower limb veins in screening patients with spinal cord injuries for deep venous thromboses

In this prospective study, we aimed to document the rate and localization of deep venous thromboses in patients with spinal cord injuries. Patients with paraplegia or tetraplegia were screened by a serial color duplex sonography protocol for deep venous thrombosis within the first 36 hours after admission, at day 7, and at day 21. Sonography was performed by a complete scan including the veins below the knee. A total of 139 patients were included (19-90 years, 63.5% male). Cumulative rate of deep venous thrombosis after 3 duplex scans was 45.3% (n = 63). In 71.4% (n = 45), thromboses were localized below the knee. Because of the relevant number of distal vein thromboses, inclusion of the calf veins during screening scans is suggested. Further studies are needed to analyze the clinical benefit of diagnosing and treating distal vein thromboses.

Low molecular weight heparin for prevention of venous thromboembolism in patients with lower-leg immobilization

BACKGROUND

Immobilization of the lower leg is associated with venous thromboembolism. Low molecular weight heparin (LMWH) is an anticoagulant treatment which might be used in adult patients with lower-leg immobilization to prevent deep venous thrombosis and its complications.

OBJECTIVES

To investigate the current literature on thromboprophylactic practice for patients with lower-limb injuries who are immobilized in plaster casts or braces, to assess the need for concrete guidelines, and to assess whether it is possible to come to an evidence-based conclusion.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Disease Group searched their Specialized Register (last searched 20 May 2008) and the Central Register of Controlled Trials (CENTRAL) (last searched The Cochrane Library 2008, Issue 2). We searched MEDLINE (until May 2008) and EMBASE (until May 2008) and reference lists of articles. We contacted pharmaceutical companies of LMWHs for relevant studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that described thromboprophylaxis by means of LMWH compared with no prophylaxis or placebo in adult patients with lower-leg immobilization. Immobilization was by means of a plaster cast or brace.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. The review authors contacted the trial authors for additional information if required. Statistical analysis was carried out using Review Manager (RevMan 5).

MAIN RESULTS

We included six RCTs fulfilling the above criteria with a total of 1490 patients. We found an incidence of venous thromboembolism ranging from 4.3% to 40%, in patients who had a leg injury that had been immobilized in a plaster cast or a brace for at least one week and who received no prophylaxis, or placebo. This number was significantly lower in patients who received daily subcutaneous injections of LMWH during immobilization (event rates ranging from 0% to 37%; odds ratio (OR) 0.49; fixed 95% confidence interval (CI) 0.34 to 0.72; with minimal evidence of heterogeneity with an I(2) of 20%, P = 0. 29). Comparable results were seen in the following subcategories: operated patients, conservatively treated patients, patients with fractures, patients with soft-tissue injuries, patients with proximal thrombosis, patients with distal thrombosis and patients with below-knee casts. Complications of major bleeding events were extremely rare (0.3%) and there were no reports of heparin-induced thrombocytopenia.

AUTHORS' CONCLUSIONS

Use of LMWH in outpatients significantly reduces VTE when immobilization of the lower leg is required.

Should all patients undergo postoperative duplex imaging to detect a deep vein thrombosis after varicose vein surgery?

OBJECTIVES

Deep vein thrombosis (DVT) is a serious complication of varicose vein surgery, with attendant risks of pulmonary embolization. Prospective duplex screening identifies DVT in 5% of patients compared to clinical incidence of approximately 1%. Universal duplex screening is costly, and the benefits of diagnosing subclinical DVT are unproven. This study evaluates whether a policy of using clinical indications (leg swelling) to determine the need for duplex imaging is safe after varicose vein surgery.

METHODS

Patients undergoing varicose vein surgery over a 4-year period were studied. Postoperative venous duplex imaging was performed if leg swelling occurred within 6 weeks of surgery. Long-term follow-up was performed to detect any missed occurrence of clinical DVT or pulmonary embolism.

RESULTS

A total of 411 patients had 491 leg operations with 80 bilateral procedures (27%); 29 patients with leg swelling underwent duplex imaging, 5 of whom had duplex-proven DVT. No patient without early clinical signs went on to develop clinical DVT on long-term follow-up.

CONCLUSION

A policy of using clinical signs as a triage for duplex imaging detected all clinically significant DVTs and generated manageable workloads for our vascular laboratory.

Short-term and mid-term outcome of isolated symptomatic muscular calf vein thrombosis

BACKGROUND

Although muscular calf vein thrombosis (MCVT) is commonly seen in everyday practice, no treatment guidelines are available. This study evaluated short-term and mid-term outcome of isolated symptomatic MCVT.

METHOD

We included prospectively and consecutively all patients referred to an outpatient clinic with isolated MCVT. Clinical signs were pain or edema, or both, of the calf. Diagnosis was established with duplex ultrasound (DUS) examination. Not completely occlusive and asymptomatic MCVTs were excluded. Patients were followed up clinically and with DUS at 1, 3, and 9 months, and up to 36 months. Anticoagulant therapy at curative dosage associated with compression was prescribed for 1 month and was extended for 2 additional months in case of incomplete recanalization at 1 month or if risk factors for venous thromboembolism (VTE) were present.

RESULTS

Included were 128 patients (78 women, 50 men) presenting with 131 MCVTs. Their mean age was 57.02 +/- 15.36 years (range, 20 to 87 years). Thrombus was present in the soleal veins (SoV) in 73 patients (55.7%) and in the medial gastrocnemius veins (MGV) in 58 (44.3%). Initial symptoms were isolated pain in the calf in 90 patients, isolated edema of the calf in six, and pain plus edema in 32. Anticoagulant therapy was prescribed in 53 patients (41.4%) for 1 month, in 59 (46.1%) for 3 months, and in 13 (10.2%) for >or=6 months. At baseline, nine pulmonary embolisms (7%), complicated with MCVT, were observed in six MGV patients (10.3%) and three SoV patients (4.1%; P = .18). Two nonfatal hemorrhagic events occurred. Three patients died during the follow-up after anticoagulant therapy had been discontinued. Recanalization of MCVT was considered complete at 1, 3, and 9 months in 54.8%, 84.7%, and 96% of cases, respectively, with no significant difference between the MGV and the SoV groups. Twenty-nine VTE symptomatic recurrences (PE, n = 6; DVT including MCVT, n = 23) were observed in 24 patients (18.8%), with similar figures in both thrombosis groups: none at 3 months, 11 between 3 and 9 months and 18 between 9 and 36 months. No extension of the MCVT or a recurrence of VTE was observed in patients treated with anticoagulant therapy. Twelve cases of superficial thrombophlebitis occurred during the follow-up period.

CONCLUSION

This study confirms the place of MCVT in VTE disorders. Pulmonary embolism at the MCVT initial diagnosis was not rare, and mid-term follow-up (mean, 26.7 months) revealed that 18.8% of patients had at least one VTE recurrence. The treatment of acute MCVT needs to be standardized because no guidelines currently exist.

Late results of catheter-directed recombinant tissue plasminogen activator fibrinolytic therapy of iliofemoral deep venous thrombosis

PURPOSE

To evaluate the efficacy of catheter-directed low-dose recombinant tissue-type plasminogen activator infusion in the treatment of iliofemoral deep venous thrombosis and prevention of post-thrombotic syndrome.

METHOD

Eighteen patients (out of 260 evaluated) with acute iliofemoral deep venous thrombosis and no previous evidence of venous insufficiency were prospectively selected for thrombolytic therapy. Catheter-directed low-dose recombinant tissue-type plasminogen activator (1 mg/h) was infused into the thrombotic segments.

RESULTS

Effective fibrinolysis was achieved in 14 of 18 cases, with correlation between effective fibrinolysis and major/complete resolution of acute signs and symptoms (P <.01). There were no episodes of major complications. Four patients presented with early rethrombosis (1 to 8 weeks). Individuals were followed for a period up to 131 weeks (average, 85.2). The incidence of clinical signs and symptoms of venous insufficiency and duplex-scan findings of valvular reflux was significantly lower in the patients in which lytic therapy succeeded and patency was kept, compared with patients experiencing acute therapeutic failure or rethrombosis (P <.01).

CONCLUSIONS

Low-dose recombinant tissue-type plasminogen activator fibrinolytic therapy is safe and effective in the treatment of acute iliofemoral venous thrombosis. The late evolution as revealed clinically and by ultrasound was superior in patients for whom lytic therapy was effective.

Frequency and determinants of the postthrombotic syndrome after venous thromboembolism

PURPOSE OF REVIEW

Postthrombotic syndrome (PTS) is the most common complication of deep venous thrombosis (DVT). Identifying which patients are at high risk of developing PTS would help improve the management of patients with DVT and allow physicians to provide patients with individualized information on their expected prognosis. This review discusses the knowledge gained from key studies over the last decade on the incidence and determinants of PTS, with special emphasis on published studies from the last 2 years.

RECENT FINDINGS

About a third to half of DVT patients will develop PTS, in most cases within 1-2 years of acute DVT. Important risk factors for PTS appear to be ipsilateral recurrence of DVT, poor quality of initial anticoagulation for the treatment of DVT and increased body mass index.

SUMMARY

Preventing DVT recurrence by providing adequate intensity and duration of anticoagulation for the initial DVT and using effective thromboprophylaxis in high-risk settings is likely to reduce the frequency of PTS. Despite some advances in identifying risk factors for PTS, however, it is still not possible to reliably predict an individual patient's risk of developing PTS after an episode of DVT. Further studies of clinical determinants and biological markers of increased risk of PTS are needed to ultimately improve long-term prognosis after DVT.

The post-thrombotic syndrome: progress and pitfalls

The post-thrombotic syndrome (PTS) develops in up to one half of patients after symptomatic deep venous thrombosis (DVT) and is the most common complication of DVT. Typical features of PTS include chronic pain, swelling, heaviness, oedema and skin changes in the affected limb. In severe cases, venous ulcers may develop. The frequency of PTS is likely to be reduced by preventing DVT with the use of effective thromboprophylaxis in high-risk patients and settings and by minimising the risk of ipsilateral DVT recurrence. Use of compression stockings for 2 years after DVT appears to reduce the incidence and severity of PTS but issues remain regarding their use and effectiveness. Future research should focus on elucidating the pathophysiology and risk factors for PTS, assessing the safety and effectiveness of catheter-directed thrombolysis to prevent PTS and evaluating the optimal use of compression stockings to prevent and treat PTS. In addition, new therapies to treat PTS should be sought and evaluated.

The Post-thrombotic Syndrome: The Forgotten Morbidity of Deep Venous Thrombosis

The postthrombotic syndrome (PTS) is the most common complication of deep venous thrombosis (DVT) yet has received little attention from clinicians and researchers. Clinically, PTS is characterized by chronic pain, swelling, heaviness and other signs in the affected limb. In severe cases, venous ulcers may develop. PTS is burdensome and costly to patients and society because of its high prevalence, severity and chronicity. Preventing DVT with the use of effective thromboprophylaxis in high-risk patients and settings and minimizing the risk of ipsilateral DVT recurrence are likely to reduce the frequency of PTS. Compression stockings worn daily after DVT appear to reduce the incidence and severity of PTS but questions regarding their use and effectiveness remain. Future research should focus on identifying patients at high risk for PTS, assessing the role of thrombolysis in preventing PTS and evaluating the optimal use of compression stockings in preventing and treating PTS. In addition, new therapies to treat PTS should be sought and evaluated.

Patterns of Venous Insufficiency after an Acute Deep Vein Thrombosis

BACKGROUND

The purpose of this study was to investigate patterns of venous insufficiency during a 12-month period after an acute deep vein thrombosis.

STUDY DESIGN

Seventy limbs in 67 patients with an acute deep vein thrombosis (DVT) involving 147 anatomic segments were evaluated with duplex scanning at 1 month, 3 months, 6 months, and 1 year. Venous segments were examined whether they were occluded, partially recanalized, or totally recanalized, and the development of venous reflux was evaluated.

RESULTS

The segments investigated were the common femoral vein (38 segments), femoral vein (33 segments), popliteal vein (36 segments), and calf veins (40 segments). There were 35 limbs with isolated DVT and the remaining 35 had multisegment DVT. At 1 year, thrombi had fully resolved in 76% of the segments, 20% remained partially recanalized, and 5% were occluded. The venous occlusion was most predominant in the femoral vein (21%) at 1 year. On the contrary, rapid recanalization was obtained in calf veins than in proximal veins at each examination (p < 0.01). Deep vein insufficiency was detected as early as 1 month after development of DVT, and the reflux was most predominant in popliteal veins (56%), followed by femoral veins (18%). No reflux was found in calf veins. Multisegment DVTs had a significantly higher incidence of deep vein insufficiency than single segment DVTs at 1 year. Development of superficial venous insufficiency was found in 5 limbs (7%) and perforating vein insufficiency in 5 (7%).

CONCLUSIONS

Lower extremity venous segments showed different proportions of occlusion, partial recanalization, and total recanalization. Calf veins showed more rapid recanalization than proximal veins. Venous reflux was noted as early as 1 month. The limbs involving multisegment DVTs on initial examination had a higher incidence of deep vein insufficiency and could require much longer followup studies.

Is bilateral duplex scanning necessary in patients with symptoms of deep venous thrombosis?

BACKGROUND

Venous duplex ultrasound scanning (VDUS) has been shown to be an accurate non-invasive means to diagnose symptomatic deep venous thrombosis (DVT). The aim of our study was to determine whether bilateral VDUS is necessary in patients who present with symptoms of DVT.

METHODS

We retrospectively reviewed the results of bilateral lower extremity VDUS performed on 1029 inpatients at Royal Prince Alfred Hospital in the 24 months from 1 January 1998 to 31 December 1999.

RESULTS

Of the 1029 patients, 705 (69%) presented with unilateral symptoms and 324 (31%) with bilateral symptoms. The overall incidence of DVT was 168 (16% of 1029 patients). In 705 patients with unilateral symptoms the diagnosis of DVT was confirmed in 120 (17.0%), of whom 20 (16.7%) had unsuspected bilateral DVT. There were 12 patients (1.7% of the 705 patients) who had DVT in the asymptomatic limb, without DVT identified in the symptomatic limb. Overall there were 32 (5% of 705) patients with unilateral symptoms who had unsuspected DVT in the asymptomatic limb. Of the 20 patients with bilateral DVT, only one patient had more extensive DVT in the asymptomatic limb than in the symptomatic limb, that was therefore likely to alter treatment. Bilateral symptoms of DVT were present in 324 (31.5%) patients, 48 (14.8%) of whom were found to have DVT. Nineteen (39.6%) of these DVTs were bilateral.

CONCLUSION

Overall the diagnostic yield of VDUS was low in this study, with an incidence of 16% of DVT detected in symptomatic patients. Techniques that improve the diagnostic yield of VDUS in symptomatic patients are required. A significant proportion (23%) of the DVT detected in this study were bilateral, and a small but significant proportion (10%) of DVT found in patients presenting with unilateral symptoms were only in the asymptomatic contralateral limb. Our study supports bilateral VDUS in symptomatic inpatients, as the detection of DVT in asymptomatic limbs aids future patient management if symptoms develop in the asymptomatic limb.

Short-term natural history of isolated gastrocnemius and soleal vein thrombosis

OBJECTIVE

Lower extremity deep vein thrombosis is often isolated to the sinusoidal veins draining the gastrocnemius and soleus muscles. The purpose of this study was to establish the incidence rate of propagation of isolated gastrocnemius and soleal vein thrombosis (IGSVT) into the deep veins of the calf and thigh.

METHODS

All patients who were referred for color flow duplex ultrasonography (CFDU) for suspected deep vein thrombosis were prospectively evaluated for IGSVT. Patients with IGSVT received no systemic anticoagulation therapy and underwent serial CFDU at 5, 9, 14, 30, and 90 days after recruitment. The incidence and extent of IGSVT propagation were noted. Factors predictive of IGSVT extension were sought, including age, gender, side, symptoms, ambulatory status, and the presence of comorbid illness, including cardiac disease, cancer, hypercoagulable states, recent surgery or trauma, and previous venous disease.

RESULTS

One hundred thirty-five limbs with IGSVT were studied for 3 months, and 16.3% of cases with IGSVT extended the thrombus to the level of the adjacent tibial, or peroneal, veins or higher. Only 3% of the cases with IGSVT propagated as cephalad as the popliteal vein, and 90.9% of IGSVT propagation occurred within 2 weeks of CFDU diagnosis. No IGSVT propagated to the level of the popliteal vein beyond 2 weeks from the time of CFDU diagnosis. No IGSVT extended into the deep veins of the thigh. By the end of the 3-month study period, 45.9% of thrombi had completely resolved. Only the presence of cancer was prognostic for IGSVT progression.

CONCLUSION

During the 3-month study period, the short-term incidence rate of untreated IGSVT propagation to the level of the popliteal vein, even in the presence of cancer, was only 3%. Follow-up imaging to detect IGSVT propagation beyond 2 weeks from the time of diagnosis may not be necessary.

Incidence and natural history of below-knee deep venous thrombosis in high-risk trauma patients

BACKGROUND

Venous thromboembolic disease remains a difficult problem in the trauma patient population. The purpose of this study was to delineate the incidence and natural history of below-knee deep venous thrombosis (BKDVT) in high-risk trauma patients.

METHODS

Patients were stratified into risk categories (low, high, or very high) for deep venous thrombosis on the basis of an institutional practice management guideline and known risk factors. All at-risk patients received either sequential compression devices (SCDs) or subcutaneous heparin (SQH) compounds, and high-risk patients also underwent weekly surveillance by duplex scanning. Very-high-risk patients had prophylactic inferior vena cava (IVC) filter placement. This prospective, observational study examines the duplex results on all high-risk patients. Data regarding method of prophylaxis, the incidence of proximal propagation on serial duplex examinations, and changes in management (anticoagulation or IVC filter placement) were collected on the high-risk patients who developed a BKDVT.

RESULTS

Between March 1997 and June 2001, 601 patients were stratified into the high-risk category and underwent a total of 1,109 duplex examinations. Eighty-five patients (14.1%) had 113 BKDVTs. These patients underwent a total of 212 duplex examinations; all patients developed their BKDVTs within 34 days. Weekly incidence was 40 (47.1%), 25 (29.4%), 15 (17.6%), 1 (1.2%), and 4 (4.7%) for weeks 1 through 5, respectively. SCDs, SQH compounds, and SCDs with SQH compounds were used on 73, 3, and 9 patients, respectively. In 4 of 85 (4.7%) patients, the BKDVT propagated proximally to an above-knee location in 4 to 8 days. Two of these patients were anticoagulated, and two underwent placement of an IVC filter. One patient (1.2%) with a BKDVT that had not propagated on duplex study developed a pulmonary embolus.

CONCLUSION

Patients identified as high-risk by our practice management guideline had a 14.1% incidence of a BKDVT; 94.1% were diagnosed within the first 3 weeks of hospitalization. Proximal propagation occurred in 4.7% and led to changes in management. Serial duplex examination of the BKDVT alone, rather than systemic anticoagulation or IVC filter placement, appears to be a reasonable treatment alternative.

The post-thrombotic syndrome: current knowledge, controversies, and directions for future research

The post-thrombotic syndrome (PTS) is a long-term complication of deep venous thrombosis (DVT) that is characterized by chronic, persistent pain, swelling and other signs in the affected limb. PTS is common, burdensome and costly. It is likely to increase in prevalence, since despite widespread use of and improvements in the efficacy of thromboprophylaxis, the incidence of DVT has not decreased over time. About 20-50% of patients develop PTS within 1-2 years of symptomatic DVT, and severe PTS, which can include venous ulcers, occurs in 5-10% of cases. Although there is no gold standard for the diagnosis of PTS, the presence of typical clinical features in a patient with previous DVT provides strong supporting evidence. Objective evidence of venous valvular incompetence helps to confirm the diagnosis in symptomatic patients. Preventing ipsilateral recurrence of DVT, by ensuring an adequate duration and intensity of anticoagulation for the initial DVT and by prescribing situational thromboprophylaxis after discontinuation of oral anticoagulants, is likely to reduce the risk of developing PTS. There is no proven role for thrombolysis of the initial DVT to prevent PTS. Daily use of graduated compression stockings after DVT may reduce the risk of PTS, and may prevent worsening of established PTS. Pending the results of ongoing studies, stockings are recommended in patients with persistent symptoms or swelling after DVT. Future research should focus on standardizing criteria for PTS diagnosis, identification of DVT patients at high risk for PTS, and rigorously evaluating the effectiveness of stockings, thrombolysis, and venoactive drugs in preventing or treating PTS.

Early thrombus remodelling of isolated calf deep vein thrombosis

OBJECTIVE

this prospective study was designed to evaluate the evolution of thrombus propagation and lysis in relation to patterns and distribution of isolated calf DVT.

METHODS

fifty-two limbs in 48 patients mean age 59+/-15, range 24-78 years, with isolated calf DVT that had at least one exam within 10 days of DVT detection were included in the study. Patients with a documented episode of prior DVT or evidence of post-thrombotic changes during the initial ultrasound exam were excluded. The initial thrombus length, patterns and location of the thrombi were recorded. On follow-up the propagation and lysis patterns of the clot were studied.

RESULTS

remodelling of the thrombus, excluding echotexture and vein diameter changes on ultrasound, occurred in 23 limbs, (44%). Ascending propagation only was seen in seven limbs (13%) descending propagation only in two (4%) and in both directions in five (10%). Propagation at least to popliteal vein was detected in seven limbs (13%). Thrombus developed or extended to initially uninvolved veins in six limbs (12%). Pulmonary embolism developed only in one patient (2%; 95% CI: 0-11%). The site and the size of thrombus or the number of veins involved in the baseline exam did not correlate with the remodeling of thrombus. Soleal and gastrocnemial veins were comparable with the posterior tibial and peroneal veins in terms of thrombus propagation and lysis.

CONCLUSIONS

early thrombus remodelling occurs in 44% of limbs with isolated calf DVT. This includes ascending and descending thrombus propagation and lysis. Thrombus development or propagation to initially uninvolved calf veins is found in 12%. Thrombus remodelling does not appear to be related to size, site and patterns of thrombosis.

The effects of heparin and oral anticoagulants on thrombus propagation and prevention of the postphlebitic syndrome: a critical review of the literature

Based on a comprehensive literature search, this report aims to examine the effects of heparin and oral anticoagulants on thrombus propagation and prevention of the postphlebitic syndrome. The effects on recurrence of thromboembolic disease have not been addressed. It is concluded that published reports of serial venograms and ultrasound examinations of patients treated with conventional anticoagulant therapy for deep venous thrombosis show either no change or thrombus extension in the first few months in approximately 50% of cases. Approximately two thirds of patients will have damage to the venous valves, leading to incompetence or other hemodynamic changes. More than one third of patients so treated may have oedema, leg pain, or other severe symptoms on long-term follow-up. The consistency with which these outcomes have been observed, particularly in many large, recent, prospective trials, adds to the credibility of these figures. The results of prospective controlled trials have failed uniformly to show any significant local benefits of anticoagulant therapy for deep vein thrombosis compared with other treatments or placebo. There does not seem to be any convincing evidence that heparin exerts a favorable influence on pulmonary embolism in situ or on portal vein thrombosis. Use of anticoagulant therapy to limit thrombus propagation therefore cannot be said to be "evidence based." These generally poor outcomes with regard to postphlebitic complications should lead to an active exploration of alternative methods of management. Substantial uncertainties surrounding many fundamental aspects of the treatment of this disease remain, and further placebo-controlled trials are needed.

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 valve station changes in "primary" and postthrombotic reflux: an analysis of 149 cases

The purpose of this study was to analyze valve station changes noted during venous valve reconstruction and the associated outcome. One hundred and forty-nine valve reconstructions were available for analysis at the time of surgical exploration; the venous valve was graded according to valve station changes (VS grades) from zero through six. Ascending venography was analyzed by a similar grading system and the two methods were compared. The results of this analysis showed that valve station wall changes are frequently present in patients with deep venous reflux and pose technical challenges during valve reconstruction; the outcome, however, appears unaffected. Grade 0 to 1 valve station changes are predominantly due to "primary" reflux, with an occasional instance of postthrombotic etiology. Grade 2 or 3 valve station changes are roughly evenly divided between phlebosclerosis of primary reflux and postthrombotic etiologies. The mechanism of onset of reflux with preservation of valve cusps in the latter group of postthrombotic cases is probably different from currently accepted theories of evolution of postthrombotic changes. Postthrombotic valve damage is variable, and the valve station anatomy may be sufficiently preserved in some patients to allow direct valve repair.