Isolated Calf Vein Thrombosis Research Articles

The “legacy” of the 125I-fibrinogen test and current management of isolated calf vein thrombosis: The end of a 40-year debate

Prior to 1970 the true incidence of postoperative dep vein thrombosis (DVT) was unknown, although surgeons were aware that pulmonary embolism (PE) occurred in 1-4% of patients. The development of the 125I-Fibrinogen test in the 1970s provided a means of screening surgical patients and demonstrated that the incidence of silent DVT varied from 17-47% depending on age, type and duration of operation. Only 4-6% of the patients with DVT developed symptoms. It has now been realised that although symptomatic isolated calf DVT is rarely associated with fatal PE, it produces local damage to venous valves with the development of reflux and post-thrombotic syndrome in 10-23% of patients and has a recurrence rate of 14%. In recent systematic reviews and meta-analyses of patients with symptomatic isolated calf DVT anticoagulation therapy up to 3 months reduces the incidence of recurrent DVT from 7.9% to 1.65% (RR 0.25; 95% CI 0.10-0.67). When anticoagulation period of 3 months was compared with 6 weeks it reduced the incidence of DVT from 14.4% to 4.8% (RR 0.32; 95% CI 0.16-0.64) Current guidelines of European Society of Vascular Surgery are as follows: “For patients with symptomatic calf DVT 3 months therapy is recommended over shorter durations (Class 1, Level A).

Use of Statewide Administrative Data to Assess Clinical Outcomes: A Retrospective Cohort Study of Therapeutic Anticoagulation for Isolated Calf Vein Thrombosis.

Single-center comparative effectiveness studies evaluating outcomes that can occur posthospitalization may become biased if outcomes diagnosed at other facilities are not ascertained. Administrative datasets that link patients' records across facilities may improve outcome ascertainment. To determine whether use of linked administrative data significantly augments thromboembolic outcome ascertainment. Retrospective cohort study. Patients with an acute isolated calf deep vein thrombosis (DVT) diagnosed at 1 Californian center during 2010-2013. Proximal DVT or pulmonary embolism (PE) within 180 days. We ascertained outcomes from linked California hospitalization, emergency department, and ambulatory surgery data and compared this information to outcomes previously identified from review of the center's medical records. Among 384 patients with an isolated calf DVT, 333 could be linked to longitudinal administrative data records. Ten patients had a possible proximal DVT or PE (4 more clearly so) from administrative data; all were unknown from medical record review. Eleven patients with known outcomes from medical record review had no outcome from administrative data. The adjusted odds ratio of proximal DVT or PE with therapeutic anticoagulation attenuated from 0.33 [95% confidence interval (CI), 0.12-0.87] using only medical record review to 0.64 (95% CI, 0.29-1.40) using both medical record review and possible outcomes from administrative data. Restricting the outcome to diagnoses clearly involving proximal DVT or PE, the adjusted odds ratio was 0.46 (95% CI, 0.19-1.10). Use of linked hospital administrative data augmented detection of outcomes but imperfect linkage, nonspecific diagnoses, and documentation/coding errors introduced uncertainty regarding the accuracy of outcome ascertainment.

Pulsatility Index of Popliteal Artery in Patients with Isolated Calf Vein Thrombosis: A Novel Technique for Detecting Thrombosis.

SummaryBackgroundTo investigate the usefulness of popliteal artery spectral doppler findings as a complimentary approach to isolated calf vein thrombosis (DVT).Material/MethodsWe included consecutive patients presenting with symptomatic and sonographically proven acute isolated calf DVT. Patients with thrombosis of any other vein were excluded. We classified calf vein into into four main types. We investigated how many of these four vessels had DVT and compared them with respect to the pulsatility index (PI) value of the popliteal artery.ResultsWe evaluated spectral doppler characteristics of the popliteal artery on the same side as the isolated calf vein thrombosis as well as on the opposite side. The relationship between PI values of the popliteal artery and the number of thrombosed calf veins was investigated. In patients with 1 and/or 2 thrombosed veins, the mean PI was 6.03±0.54 on the side of cDVT and 5.68±0.39 on the opposite side (p=0.008), respectively. Inpatients with 3 and/or 4 thrombosed veins, the mean PI was 8.05±0.61 on the side of cDVT and 6.34±0.47 on the opposite side (p=0.001), respectively.ConclusionsVenous doppler sonography for the evaluation of calf DVT may be limited by patient characteristics such as obesity, edema, and tenderness., Arterial PI can be used as a complimentary technique for the detection of venous thrombosis in such of cases.

Significance of Isolated Calf Vein Thrombosis-Further Evidence.

Significance of Isolated Calf Vein Thrombosis-Further Evidence.

Rediscussing Anticoagulation in Distal Deep Venous Thrombosis.

Distal deep venous thrombosis (DVT) accounts for approximately half of all the cases of lower limb thrombosis. The impact and management of this condition is still controversial. This study aims to evaluate the incidence of pulmonary embolism (PE) in patients with distal DVT in comparison to proximal DVT and evaluate the correlation between DVT and PE extension. 100 patients with acute lower limb DVT diagnosed with whole leg Doppler ultrasound from January 2006 to December 2014 were retrospectively analyzed. Active investigation for PE was carried out in all patients using multislice computed tomography angiography. Classification of DVT and PE was based on the proximal extension of the thrombus. The overall incidence of PE in our sample patients was 72%. In the subgroup analysis, incidence of PE was equal in both the proximal and distal DVT groups (77%, p > 0.99). PE was detected in 43% of the patients with isolated calf vein thrombosis (ICVT). No statistical difference was observed between the distribution of lobar, segmental and subsegmental PE in the 3 DVT subgroups (p = 0.665); however, truncular PE was only observed in the proximal DVT group. Distal DVT is associated with a high incidence of PE compared to proximal DVT. Distal DVT and ICVT can provoke PE with involvement of proximal vessels in the pulmonary arterial tree, even in asymptomatic patients. Our study arises discussion in the controversial debate regarding the need for routine anticoagulation in distal DVT.

Management of isolated calf vein thrombosis

Objective The aim of the present study was to evaluate a protocol for managing isolated calf vein thrombosis. Background Deep vein thrombosis (DVT), which is common among the general population, can lead to fatal pulmonary embolism; therefore, its early diagnosis is essential. A recent study revealed that the reason for 10% of mortality in general hospitals in the UK was pulmonary embolism. Patients and methods Forty patients with isolated calf vein thrombosis were categorized into two groups: group A, which included 20 patients with provoked isolated calf vein thrombosis; and group B, which included 20 patients with unprovoked isolated calf vein thrombosis. Results In the provoked group, 16 patients had satisfactory resolution after 10 days of therapy (80%), four patients had no resolution (20%), and no patient had progression to the popliteal vein. On the other hand, in the unprovoked group, 14 patients had satisfactory resolution (70%), four patients had no resolution (20%), and two patients had progression to the popliteal vein (10%) ( P = 0.34). Sixteen patients in the provoked group had no recurrence at the end of 3 months (80%), three patients had recurrence of the calf thrombosis (15%), and one patient had progression to the popliteal vein (5%), whereas in the unprovoked group, 14 patients had no recurrence (70%), four patients had recurrence of calf thrombosis (20%), and two patients had progression to the popliteal vein (10%) ( P = 0.74). Conclusion Provoked calf vein thrombosis can be treated with low molecular weight heparin (LMWH) for 10 days and then the duplex should be repeated after 10 days. If there is no progression to thrombus, anticoagulation therapy is stopped and the patient is asked to use elastic stockings. Unprovoked calf vein thrombosis can be treated with LMWH for 10 days, and if there is no propagation to the thrombus, we can put the patients on low intensity warfarin dose regimen - for example, 1-2 mg to adjust INR in the range 1-1.9.

Management of isolated calf vein thrombosis in cancer patients

The treatment of isolated calf vein thrombosis remains widely debated. This study highlights the characteristics of isolated calf vein thrombosis in cancer patients and compares to isolated calf vein thrombosis in patients without history of cancer. Between July 2013 and April 2014, a retrospective chart review of consecutive patients with isolated calf vein thrombosis was performed recording patient risk factors, ultrasound characteristics of the thrombus, treatment modalities, long-term recurrence of venous-thromboembolism, incidence of bleeding, and mortality. Of 131 patients with isolated calf vein thrombosis, 53 (40.1%) had history of cancer. Isolated calf vein thrombosis occurred at an older age in cancer patients (66.7 vs 58.5 years, p = 0.004). The anatomical characteristics of isolated calf vein thrombosis on ultrasound were comparable in both groups. Isolated calf vein thrombosis in cancer patients was less likely to be treated with anticoagulation (60.4% vs 80.8%, p = 0.018). However, a trend towards higher incidence of bleeding after initiation of anticoagulation for isolated calf vein thrombosis in cancer patients (11.3% vs 6.4%, p = 0.351) was noted. Mortality in cancer patients was higher (37.7% vs 9.00%, p < 0.001) but was unrelated to isolated calf vein thrombosis or its treatment. In conclusion, the risks of bleeding seem to exceed the benefits of anticoagulation in approximately 50% of cancer patients with isolated calf vein thrombosis. The management of isolated calf vein thrombosis does not seem to impact the survival of cancer patients.

Outcomes of retrievable inferior vena cava filters in patients with deep vein thrombosis and transient contraindication for anticoagulation.

PurposeTo determine the efficacy of a retrievable inferior vena cava filter (IVCF) for patients with deep vein thrombosis (DVT) and transient contraindication for anticoagulant therapy, and to analyze the risk factors for filter thrombus in these patients.MethodsWe retrospectively reviewed the records of 70 patients who received a retrievable IVCF from January 2007 to June 2014 because of documented DVT and transient contraindication for anticoagulant therapy. The protocol for follow-up care generally consisted of anticoagulant therapy after high-risk periods, follow-up CT around 2 weeks after IVCF placement, and retrieval if possible.ResultsThe 70 patients had a mean age of 61.8 years (range, 17-88 years), and 30 were male (43%). The indications for IVCF were recent trauma including surgery in 48 patients, recent hemorrhage in 14, and planned major surgery with DVT in 8 patients. Follow-up CT of 61 patients (87%) was performed. Aggravation or new development of pulmonary embolism (PE) was not found in any patient. Filter thrombus was detected in 23% of patients with follow-up CT (14/61). Filter thrombus was not detected in patients with isolated calf vein thrombosis (ICVT) (P = 0.079). The risk factor for filter thrombus was DVT progression on follow-up CT (P = 0.007) on multivariate analysis.ConclusionFor patients with DVT and transient contraindication for anticoagulant therapy, a retrievable IVCF could prevent the aggravation or new development of PE. DVT progression on follow-up CT was associated with filter thrombus and ICVT was not related to filter thrombus in the present study.

Finding the origin of pulmonary emboli with a total-body magnetic resonance direct thrombus imaging technique

Pulmonary embolism is considered to originate from embolization of a deep-vein thrombosis, resulting in two manifestations of one disease: venous thrombosis. However, in up to 50% of patients with pulmonary embolism no deep-vein thrombosis is found with ultrasonography. An explanation for this low proportion is currently lacking. Other imaging modalities may increase the yield of detection of deep-vein thrombosis in the calf or in the abdominal region. Alternatively, not all pulmonary emboli may originate from deep-vein thromboses in the extremities. We searched for the origin of pulmonary emboli, by performing total-body magnetic resonance imaging-scans to visualize thrombi. Ninety-nine patients with a first pulmonary embolism confirmed by computed tomography underwent a magnetic resonance direct thrombus imaging-scan, a validated technique using endogenous contrast. Additionally, acquired and genetic risk factors were assessed. No thrombus was found in 55 patients, whereas a thrombus was identified in 44 patients. The commonest thrombus location was the lower leg; 12 patients had isolated calf vein thrombosis and five had isolated superficial vein thrombosis. A peripheral thrombus was found by magnetic resonance imaging in less than half of patients with pulmonary embolism. We propose several hypotheses to explain the absence of thrombi, such as a cardiac thrombus origin or embolization of the whole deep-vein thrombus. The possibility that pulmonary embolism arises de novo in the lungs, due to local inflammation-driven coagulation, needs to be considered.

Early treatment outcome of isolated calf vein thrombosis after total knee arthroplasty

PurposeIn contrast to proximal deep vein thrombosis (DVT), the treatment of isolated calf vein thrombosis (ICVT) remains controversial. This study aimed to investigate early treatment outcomes of ICVT after total knee arthroplasty (TKA).MethodsMedical records of 313 patients who underwent TKA from October 2007 to December 2009 were retrospectively reviewed. A DVT-computed tomography (CT) was performed 7 days after surgery. ICVT was identified in 76 limbs of 73 patients. Of them, follow-up DVT-CT was available in 39 limbs of 37 patients. The patients with ICVTs were categorized into two groups: oral anticoagulation group (group I, 17 patients with 18 limbs) and conservative treatment group (group II, 20 patients with 21 limbs). Group I received an oral vitamin K antagonist for 3 to 6 months following low molecular weight heparin. Change of thrombus extent and development of pulmonary embolism (PE) was assessed in follow-up DVT-CT.ResultsMean age was 68 years and 95% were female. Of 39 limbs with ICVT, 16 (41%) involved major lower leg veins (posterior tibial vein or peroneal vein), 13 (33%) involved muscular veins (soleal vein or gastrocnemius vein) and 10 (26%) involved both. During 1 to 6 months, follow-up DVT-CT revealed complete thrombus resolution in all limbs and there was no proximal propagation of thrombus or PE in both groups.ConclusionThere is no evidence of DVT propagation or newly developed PE in the conservative treatment group. This result suggests that anticoagulation therapy for ICVT patients without PE after TKA may not be mandatory.

Risk factors for delayed recanalization of calf vein thrombosis

PurposeTo determine the risk factors of delayed recanalization of isolated calf vein thrombosis (CVT).MethodsOne hundred fifty limbs of 110 patients with CVT between September 2007 and April 2010 were enrolled. We used ultrasonography for the diagnosis and follow-up examinations of CVT. We calculated recanalization rates at 1 and 3 months after initial diagnosis and analyzed the risk factors associated with delayed recanalization of CVT.ResultsCVTs were located in the muscular calf vein in 110 (73.3%), in the deep calf vein in 18 (12%), and in both in 22 cases (14.7%). Among all CVTs, 94 limbs (63%) were symptomatic. Major risk factors for CVT were orthopedic surgery (87.3%), malignancy (21.3%), and immobilization (15.3%). Sixty-seven patients (60.9%) were treated with oral anticoagulation therapy, while 43 patients by low molecular weight heparin (n = 19) or by conservative methods including elastic compression stockings and ambulation (n = 21). The cumulative recanalization rate at 1 and 3 months was 23% and 82% and it was significantly higher in patients who underwent oral anticoagulation therapy compared with patients without oral anticoagulation therapy (84% vs. 65%, P = 0.008 by log-rank test). Malignancy (odds ratio [OR], 2.789; P = 0.043) and immobilization (OR, 4.191; P = 0.029) were independent risk factors for delayed recanalization of CVT and oral anticoagulation (OR, 0.300; P = 0.020) was an independent factor in promoting recanalization in multivariate analysis.ConclusionFor patients with isolated CVT, no oral anticoagulation resulted in higher rates of delayed recanalization compared to oral anticoagulation treatment. Immobilization and having malignancy were independent risk factors for delayed recanalization.

Is Deep-Vein Thrombosis Always the Origin of Pulmonary Embolism? Imaging of Veins with a Total-Body Direct Thrombus MRI Technique

Abstract 2297 IntroductionPulmonary embolism (PE) is thought to originate from embolisation of a deep-vein thrombosis (DVT), resulting in two clinical manifestations of one disease: venous thrombosis. However, in up to 50% of patients with PE, no DVT is found with ultrasound. A new technique in diagnosing DVT is ‘MR Direct Thrombus Imaging' (MRDTI), using methaemoglobin in the thrombus as endogenous contrast. We performed total body MRIs to visualize thrombi from calf veins to subclavian veins, to assess the origin of PE. MethodsConsecutive patients with a first PE diagnosed by Multi Detector CT scan are included. All patients undergo a 1.5 T MRDTI scan. In addition, blood is sampled for determination of genetic risk factors: the Factor V Leiden (FVL) and prothrombin G20210A (FII) mutations. Results99 patients have been enrolled in the study. In 44/99 (44%) a thrombus was identified on MR images. Most thrombi originated from the left side of the body (27/44). The upper leg was involved most often (22/44), with thrombi extending into the calf in 16 of these patients. Other thrombi were present in the pelvic veins (4/44), and deep calf veins alone (12/44). 6 patients had merely thrombophlebitis. The FVL mutation was present in 14% (95% CI 6–27) of patients with a thrombus on MRI, and in 7% (95% CI 3–18) of patients without a thrombus. For FII, the prevalence in the group with a DVT on MRI was 2% (95% CI 0.4–12) and without a DVT 4% (95% CI 1–13). ConclusionIn less than half of PE patients a thrombus can be found with total body MRI. When thrombi were present, they were mainly found in the upper leg, extending into the calf veins. Interestingly, 27% of PEs with a thrombus on MRI was related to isolated calf vein thrombosis and 14% to thrombophlebitis. In PE patients with no thrombus on MRI, a local origin of PE, a thrombus from cardiac origin or complete embolisation needs to be considered.Supported by Netherlands Heart Foundation grant number 2009B050 Disclosures:No relevant conflicts of interest to declare.

Early follow-up and treatment recommendations for isolated calf deep venous thrombosis

The clinical significance of isolated calf vein thrombosis (ICVT) remains controversial. Several studies have shown that the majority of ICVT do not propagate above the knee while other studies have suggested ICVT propagation and recommend full anticoagulation. The purpose of this study was to determine the progression of ICVT, identify risk factors for clot propagation, and to evaluate further thrombotic events associated with it. This study consisted of 156 patients and a total of 180 limbs. All patients included had ICVT involving either the tibial, peroneal, gastrocnemius, or the soleal vein. After initial diagnosis, all patients were started on prophylactic dose of low molecular weight heparin (LMWH) or unfractionated heparin, unless already anticoagulated. All limbs were monitored using duplex ultrasonography scans at intervals of 2 to 3 days, 1 to 3 months, and 6 to 8 months from the initial time of diagnosis. Outcomes examined included lysis of clot, propagation to a proximal vein, and pulmonary emboli. ICVT was detected in 180 limbs of 156 patients. No significant difference was noted in the gender of the patients or limb preference. Twenty-four patents had both limbs involved. The mean age was 77 years old and the mean follow-up was 5.1 months. The soleal vein was most commonly involved. The second most common vein involved was peroneal, followed by posterior tibial and then gastrocnemius. The least commonly involved vein was the anterior tibial with only one positive result on each side. Fifteen of 180 limbs (9%) had complete resolution of the thrombus within 72 hours. Of these, six were anticoagulated to a therapeutic level. All patients had a follow-up duplex scan within 1 to 3 months' time, and none had recurrence. At the 1 to 3-month follow-up, 11 of 180 patients (7%) had propagation to a proximal vein; all of whom were in a high-risk group to develop a deep vein thrombosis (DVT), either after an orthopedic procedure, stroke, or malignancy. Nine of 156 patients developed a pulmonary emboli also diagnosed within the 1 to 3-months' time period. At the 6 to 8-month follow-up, there was no further propagation of any additional limbs and no further incidences of pulmonary emboli. ICVT can be safely observed in asymptomatic patients without therapeutic anticoagulation. In our study, patients who have had orthopedic procedures, those with malignancy, and those that were immobile seemed to have a higher incidence of clot propagation. In this group, we recommend full anticoagulation until the patient is ambulatory or the follow-up duplex scan is negative. Our data also suggest that a follow-up duplex scan is not beneficial when performed within 72 hours or after 3 months.

Clinical Characteristics of Patients with Isolated Calf Vein Thrombosis in a Large Teaching Hospital

Objective. To identify the clinical characteristics of a patient population newly diagnosed with acute isolated calf deep venous thrombosis (ICDVT) by duplex ultrasound scan (DUS). Methods. A retrospective review of the records of 100 consecutive patients diagnosed with ICDVT by DUS was conducted. Results. Patients (59% male) were predominantly Caucasian (86%) and inpatients (69%) with an average age of 53 years. The most frequent risk factors were malignancy (22%), immobility (18%), and previous DVT (13%). Thrombus was present in named tibial veins in 58% and muscular branches in 42%. The peroneal vein was most frequently involved (39/117, 33%) followed by the gastrocnemius veins (29/117, 22%) and muscular calf tributaries (14%). Conclusions. Our patient population with ICDVT was predominantly symptomatic, in-patient cohort with a high incidence of risk factors such as malignancy, immobility, previous DVT, trauma, and postoperative status. Partial or complete resolution was documented by DUS in 53%.

Isolated Calf Vein Thrombosis Should Be Treated With Anticoagulation

D-dimer levels are closely related to the clinical status of deep vein thrombosis (DVT). This study aimed to investigate the factors which were associated with the normalization of D-dimer level by vitamin K antagonist (VKA) therapy, the maintenance of normal D-dimer levels for 6 months during VKA therapy, and the recurrent elevations of D-dimer above normal level after VKA withdrawal, in DVT of the legs.The 469 consecutive patients with first-episode leg swelling were examined. All blood tests were measured from the initially sampled blood before the administration of medications.Of the 469 patients, 288 (61.4%) showed positive D-dimer test. Radiologic examinations, including Doppler ultrasound and computed tomography venography, of the 288 patients revealed positive DVT of the legs in 135 (46.9%) patients and of these, 122 with total follow-up durations of >6 months were enrolled in this study. Linear regression analysis of 100 patients who experienced D-dimer normalization revealed initial D-dimer levels were positively correlated with D-dimer normalization time during VKA therapy (P = 0.010). Logistic regression analysis showed initial D-dimer level was negatively associated with the normalization of D-dimer levels by VKA therapy (P = 0.045), and being a woman (P = 0.005) and having lower protein C (P = 0.002) level had negative impacts on the maintenance of normal D-dimer levels for 6 months during VKA therapy. Finally, after VKA withdrawal, the recurrent elevations of D-dimer above normal level were more likely to occur in women than in men (P = 0.004).From these observations, it is suggested that higher initial D-dimer level, lower protein C level, and female gender may be the adverse risk factors for the treatment of DVT of the legs using VKA.

359: Isolated Calf Vein Thrombosis: Implications for Emergency Physician-Performed Compression Ultrasonography

Calf veins are not evaluated for thrombosis by emergency physician-performed compression ultrasonography (EPPCU) to rule out lower extremity deep venous thrombosis (DVT). Emergency department (ED) patient compliance with follow-up for repeat ultrasonography (US) examinations to rule out propagation of distal DVTs after a negative EPPCU is very low. Most recent guidelines recommend treating symptomatic isolated calf vein thrombi with anticoagulation to reduce the risk of thrombus extension, recurrent DVT, post-thrombotic syndrome and chronic venous insufficiency.

Serial 2-Point Ultrasonography Plus D-Dimer vs Whole-Leg Color-Coded Doppler Ultrasonography for Diagnosing Suspected Symptomatic Deep Vein Thrombosis

Patients with suspected deep vein thrombosis (DVT) of the lower extremities are usually investigated with ultrasonography either by the proximal veins (2-point ultrasonography) or the entire deep vein system (whole-leg ultrasonography). The latter approach is thought to be better based on its ability to detect isolated calf vein thrombosis; however, it requires skilled operators and is mainly available only during working hours. No randomized comparisons are yet available evaluating the relative values of these 2 strategies. To assess if the 2 diagnostic strategies are equivalent for the management of symptomatic outpatients with suspected DVT of the lower extremities. A prospective, randomized, multicenter study of consecutive symptomatic outpatients (n = 2465) with a first episode of suspected DVT of the lower extremities who were randomized to undergo 2-point or whole-leg ultrasonography. Data were taken from ultrasound laboratories of 14 Italian universities or civic hospitals between January 1, 2003, and December 21, 2006. Patients with normal ultrasound findings were followed up for 3 months, with study completion on March 20, 2007. Objectively confirmed 3-month incidence of symptomatic venous thromboembolism in patients with an initially normal diagnostic workup. Of 2465 eligible patients, 345 met 1 or more exclusion criteria and 22 refused to participate; therefore, 2098 patients were randomized to either 2-point (n = 1045) or whole-leg (n = 1053) ultrasonography. Symptomatic venous thromboembolism occurred in 7 of 801 patients (incidence, 0.9%; 95% confidence interval [CI], 0.3%-1.8%) in the 2-point strategy group and in 9 of 763 patients (incidence, 1.2%; 95% CI, 0.5%-2.2%) in the whole-leg strategy group. This met the established equivalence criterion (observed difference, 0.3%;95% CI, -1.4% to 0.8%). The 2 diagnostic strategies are equivalent when used for the management of symptomatic outpatients with suspected DVT of the lower extremities. clinicaltrials.gov Identifier: NCT00353093.

Incidence and Distribution of Lower Extremity Deep Vein Thrombosis in Rehabilitation Patients: Implications for Screening

Patients admitted to in-patient rehabilitation programs have an increased risk for developing deep venous thrombosis (DVT). However, the utility of screening for lower extremity DVT using duplex ultrasound in this high-risk population is not well characterized. The purpose of this study is to identify whether or not screening lower-extremity duplex exams are indicated in this high-risk population. Screening lower extremity duplex exams were performed on all patients admitted to the rehabilitation center at Mt. Sinai Hospital over a 3-year period. Charts were reviewed for patient age, gender, diagnosis, date of screening and follow-up duplex exams, presence and location of venous thrombosis at each duplex exam, history of anticoagulation, and medical DVT prophylaxis. The presence of DVT at screening, the location of DVT along the lower extremity, and the outcome of calf DVT were analyzed in terms of gender, underlying diagnosis, and history of DVT prophylaxis. Lower extremity DVT was detected in 34% of patients. Twenty-three percent of patients had isolated calf vein thrombosis. Men were more likely than women to have DVT. Calf DVTs progressed in 3% of patients over an average follow-up of 2 weeks. The presence of DVT, its location along the lower extremity, and the outcome of calf vein DVT had no significant relationship to underlying diagnosis or history of prophylaxis. Screening duplex exams to detect lower extremity DVT in rehabilitation patients is useful. Screening altered management in 26% of patients, prompting either anticoagulation or repeat duplex exam.

Traveler-s Thrombosis: A Systematic Review

Anecdotal evidence suggests a possible link between travel and venous thromboembolism (VTE). We systematically evaluated the evidence from observational studies. We searched studies evaluating the risk of venous thrombosis in relation to traveling from MEDLINE and EMBASE up tp March 2004, together with a hand search of reference lists from retrieved literature, and we contacted some of the experts. Observational studies estimating the risks of VTE and isolated calf vein thrombosis were eligible. Methodologic quality was assessed based on prior criteria, and meta-analysis was considered where applicable. A total of 194 English-language publications were initially identified. Sixteen studies were included: 9 case-control, 2 prospective controlled, and 5 other observational studies. They differed drastically in study designs, selection of controls where applicable, mode and duration of travel, and subtypes of VTE under consideration. Ten studies concluded that travel, mostly through air and of prolonged duration, is a risk factor for venous thrombosis and/or pulmonary embolism, and the risk increases for passengers with preexisting venous thrombosis risk factors. Outcomes examined ranged from asymptomatic isolated calf muscle vein thrombosis to severe fatal pulmonary embolism. Current literature is controversial over any association between travel and VTE, and although the quality and power of these studies have been variable, studies of higher quality have shown a strong and significant association between prolonged air travel and VTE. No conclusions could be drawn about other modes of transportation. Since VTE is a disease of multifactorial causation, those with preexisting VTE risk factors are most vulnerable.

Current approaches and controversial issues in the diagnosis of deep vein thrombosis via duplex Doppler ultrasound

Duplex and color Doppler sonography (DUS) is currently the technique of choice for the diagnosis of deep venous thrombosis (DVT) in symptomatic patients, because it has proven safe and cost-effective, with a very high sensitivity and specificity (96% and 98%, respectively) for the diagnosis of proximal DVT. Several issues regarding its method and clinical indications remain controversial, however. Although isolated calf vein thrombosis does not seem to have a significant adverse outcome in the short term, scanning the calf only in patients with localized symptoms or signs is cost-effective. Bilateral examination is indicated in high-risk patients or when screening asymptomatic patients. When negative, a complete DUS examination of the proximal and distal veins, at least down to the level of the popliteal trifurcation, allows withholding anticoagulant therapy without the risk of major complications. This examination may be repeated if signs or symptoms worsen. Some populations of asymptomatic patients at high risk of DVT may benefit from DUS screening. Bilateral DUS examination of lower limb veins should be performed as the initial examination in the workflow of pulmonary embolism only in patients with risk factors for DVT. Recurrent thrombosis is a challenging diagnosis for all imaging modalities. A diagnostic strategy combining clinical probability score and D-dimer test may refine the selection of patients. The pitfalls and limitations of venous DUS are related to vein anatomy, flow changes, technical issues, and operator expertise.