The risk of recurrent venous thromboembolism in patients with unprovoked symptomatic deep vein thrombosis and asymptomatic pulmonary embolism

Patients with a first episode of symptomatic pulmonary embolism (PE) have a higher risk of recurrent venous thromboembolism (VTE) than patients with a first episode of proximal lower extremity deep vein thrombosis (DVT). Patients with symptomatic DVT and silent PE may have a different risk of VTE recurrence than patients that have symptomatic DVT without PE. Therefore, it was the aim of this prospective cohort study to compare the risk of recurrent symptomatic VTE in patients with proximal lower extremity DVT and silent PE to the risk in patients that only have proximal lower extremity DVT. Ninety-one consecutive outpatients presenting to the emergency department of a university hospital subsequently hospitalised with a first episode of unprovoked symptomatic proximal lower extremity DVT, and without new pulmonary symptoms were included. Standard initial treatment consisted of intravenous unfractionated heparin or subcutaneous low-molecular-weight heparin for 5-7 days, overlapped with oral vitamin-K antagonist therapy, with long-term oral vitamin-K antagonist therapy (goal INR 2.5 [2.0-3.0]). Study endpoints were: symptomatic recurrent DVT, new PE, and recurrent PE, evaluated by standard objective testing. At enrollment, 28 of 91 (31%) patients with DVT had silent PE. In the patients with DVT and silent PE, there were 3 VTE recurrences during 20 person-years of follow-up, while there were no VTE recurrences during 61 person-years of follow- up in the patients with isolated DVT. The Kaplan-Meier estimated VTE recurrence rate at 1 year after the diagnosis of DVT was 11% (95% CI: 2-28%) for patients with symptomatic DVT and silent PE, compared to 0% in patients with isolated symptomatic DVT (p=0.0045). In patients with a first episode of unprovoked symptomatic acute proximal lower extremity DVT, the risk of recurrent VTE was significantly higher in those with silent PE compared to those without PE.     

Circulating tissue factor positive microparticles in patients with acute recurrent deep venous thrombosis

Introduction

Circulating tissue factor positive microparticles (MPTF) were reported in a wide range of diseases with thrombotic tendency. Though D-dimer assay had a high negative predictive value for deep venous thrombosis (DVT) recurrence, there are currently no reliable positive predictors for recurrent DVT. We therefore quantified MPTF in patients with acute recurrent DVT to determine whether MPTF levels could be used to predict recurrent DVT.

Materials and Methods

Microparticles (MPs) were isolated from plasma of initial DVT patients (n = 25), recurrent DVT patients (n = 25) and sex- and age-matched healthy individuals (n = 25), stained with annexin V, cell-specific monoclonal antibodies (MoAbs) and a MoAb directed against tissue factor (TF), and analyzed by flow cytometry. We also determined the plasma procoagulant activity with a Human TF Chromogenic Activity Assay Kit.

Results

We found total MPTF to be elevated in recurrent DVT patients versus normal individuals (P = 0.001). The number of monocyte-derived MPTF in both initial and recurrent DVT was higher than in normal individuals (P < 0.01, respectively). The platelet and endothelial cell derived MPTF in recurrent DVT were significantly increased relative to other MPTF (P < 0.05), although there was no difference between initial DVT patients and normal individuals. We demonstrated elevated procoagulant activity of platelet-free plasma in DVT patients relative to normal individuals, and a positive correlation with MPTF.

Conclusions

The elevated MPTF could be a potentially predictor for DVT recurrence. Further studies are needed to validate its sensitivity and specificity.     

The diagnostic value of compression ultrasonography in patients with suspected recurrent deep vein thrombosis

Diagnosis of recurrent deep-vein thrombosis (DVT) is difficult because of limitations in distinguishing acute from old thrombi. In the past, an ultrasound method for diagnosis of recurrent ipsilateral DVT was developed, which relies on repeated measurements of the diameters of the common femoral and popliteal veins. To assess the safety of withholding anticoagulation from patients with improved or stable compression vein diameters, 205 consecutive patients presenting with suspected recurrent ipsilateral DVT were evaluated. The vein diameter was measured under compression with the transducer and compared with earlier ultrasound results. Patients with stable or improved ultrasound findings had repeat ultrasound assessments after 2 (+/- 1) and 7 (+/- 1) days. Patients with repeatedly normal ultrasound results were followed-up for six months to determine the incidence of symptomatic recurrent venous thromboembolism. Of the 205 patients, 153 had stable or improved ultrasound findings. Repeat ultrasound assessment became abnormal in 3, and recurrence was confirmed by venography in all. A six months follow-up was done in the remaining 150 patients with repeatedly normal ultrasound tests and showed 2 (1.3%; 95% CI, 0.02 to 4.7%) confirmed non-fatal venous thromboembolic complications. The positive predictive value of a stable or improved ultrasound was 90% (95% CI, 77 to 97%). In conclusion, it is safe to withhold anticoagulant treatment from patients with suspected recurrent ipsilateral DVT in whom compression ultrasonography showed improved or stable vein diameters.     

Predictors of residual venous obstruction after deep vein thrombosis of the lower limbs: a prospective cohort study

INTRODUCTION: Delayed thrombus regression after deep vein thrombosis (DVT) of the lower limbs is associated with increased risk of DVT recurrence. Predictors of residual venous occlusion are unknown. We hypothesized that obesity, which causes reduced fibrinolytic activity, can predict delayed thrombus regression. MATERIALS AND METHODS: In a prospective cohort study, 98 patients with objective diagnosis of DVT underwent compression ultrasonography (CUS) after 6 and 12 months. Persistent occlusion was arbitrarily defined as a thrombus occupying, at maximal point of compressibility, more than 20% of the vein area in the absence of compression. The body mass index (BMI) and waist circumference were measured at baseline and at follow up to assess individual patterns of body fat distribution. Information on antithrombotic treatment, family history of varicose veins, cigarette smoking, concomitant disorders, the presence of known risk factors for DVT, the duration of anticoagulant treatment and the use of elastic stockings was collected. RESULTS: Post-thrombotic recanalization was documented in 34 patients (34.7%) at 6 months and in 44 patients (44.9%) at 12 months. There was no difference in the mean BMI (p=0.469 at 12 months), in the prevalence of obesity (p=0.479) and visceral pattern of body fat distribution (p=0.239) between patients who did and did not show thrombus regression. The presence of a permanent risk factor for DVT was the only predictor of delayed thrombus regression (OR 11.0, 95% CI 1.359-61.978). CONCLUSIONS: Despite consistent evidence of impaired fibrinolysis, obesity is not associated with persistent venous obstruction.     

Abdominal obesity and the risk of recurrent deep vein thrombosis

BACKGROUND: Abdominal obesity has been found to be associated with an increased risk of deep vein thrombosis (DVT). Whether patients with abdominal obesity have an increased risk of recurrence is currently unknown. METHODS: Patients with objective diagnosis of DVT and a life expectancy of greater than 6 months underwent measurement of the circumference of the waist. A waist circumference of greater than 102 cm for men and greater than 88 cm for women defined abdominal obesity. Information on age, gender, and on the presence of risk factors for DVT was collected. At follow-up, all patients underwent serial compression ultrasound of the lower limbs and were clinically evaluated every 6 months. RESULTS: One hundred patients were enrolled, 58 with abdominal obesity and 42 without. Mean age was 64.5 and 57.3 years, respectively (p<0.05). Percentage of male patients was 32.8% and 81.0% (p<0.01). Unprovoked DVT and transient risk factors rates were similar in both groups. Overall, recurrent DVT was documented in 29 patients, 16 in patients with abdominal obesity (27.6%) and 13 in patients without (31.0%). At the multivariate regression analysis HR for VTE recurrence in abdominal obese patients was 1.26 (95% confidence interval=0.47-3.4). CONCLUSIONS: Abdominal obesity does not seem to modify the risk of recurrent DVT.     

A single complete ultrasound investigation of the venous network for the diagnostic management of patients with a clinically suspected first episode of deep venous thrombosis of the lower limbs

In patients clinically suspected of deep-vein thrombosis (DVT) of the lower limbs, it is safe to withhold anticoagulant therapy after a negative ultrasound (US) limited to the popliteal and the femoral veins, provided that this can either be repeated or combined with other diagnostic procedures. To assess the safety of withholding anticoagulants after a single negative complete US, we performed a multicenter, prospective, cohort study including consecutive ambulatory outpatients from institutional and private practice settings, with a clinically suspected first episode of DVT. Patients fulfilling the inclusion criteria were enrolled after careful clinical assessment. A complete US examination of the proximal and the distal veins was performed according to a standardized and detailed protocol. Anticoagulant therapy was administered in patients with proximal or isolated distal DVT and withheld in those with negative results. The main outcome measure was the occurrence of objectively documented clinical thromboembolic events during a three-month follow-up after a negative US. Out of 623 patients, 401 (64.4%) had a baseline negative US, were not anticoagulated and could be followed-up for three months. Two patients presented a calf DVT within three months. The incidence of venous thromboembolic events, including distal DVT, was 0.5% [95% confidence interval: 0.1-1.8]. No proximal DVT, or non-fatal or fatal pulmonary embolism occurred (incidence: 0.0% [95% confidence interval: 0.0-0.9]). In conclusion, it is safe to withhold anticoagulant therapy in patients with clinically suspected DVT after a single, negative, complete US. Integrating this method within diagnostic strategies for DVT could improve management and be more acceptable for patients and physicians.     

Thromboxane and prostacyclin formation in patients with deep vein thrombosis

The urinary excretion of 2,3-dinor-TxB2 and 2,3-dinor-6-keto-PGF1 alpha (the major urinary metabolites of thromboxane B2 and prostacyclin) was measured in ten patients with confirmed deep vein thrombosis, using specific methods based on gas chromatography - mass spectrometry with deuterium-labelled internal standards. Measurements of these major urinary metabolites makes it possible to monitor the in vivo formation of thromboxane A2 and prostacyclin. The results demonstrate an abnormally high and very variable excretion of 2,3-dinor-TxB2 and 2,3-dinor-6-keto-PGF1 alpha in patients with deep vein thrombosis. This indicate that both thromboxane A2 and prostacyclin are involved in the course of events associated with this disease.     

D-dimer levels in combination with residual venous obstruction and the risk of recurrence after anticoagulation withdrawal for a first idiopathic deep vein thrombosis

We assessed the predictive value of D-dimer levels in combination with residual venous obstruction (RVO) for recurrent venous thromboembolism (VTE) in a prospective cohort of outpatients after oral anticoagulant therapy (OAT) suspension for a first episode of idiopathic proximal deep vein thrombosis of the lower limbs during a 2-year follow-up. Patients (n=400) were enrolled on the day of OAT suspension when RVO was determined by compression ultrasonography (present in 48.6% of patients). D-dimer (cut-off value: 500 ng/mL) was measured 30+/-10 days afterwards (abnormal in 56.4% of patients). The overall recurrence rate was 16.7% (67/400; 95% confidence intervals - CI -: 13-21 %). The multivariate hazard ratio (HR) for recurrence was 3.32 (95% CI: 1.78-6.75; p<0.0001) for abnormal D-dimer compared to normal D-dimer and 1.2 (95% CI:0.72-2.07; p>0.05) for RVO compared to absent RVO. The recurrence rate was 5.7% (95% CI:2-13%) and 10.4% (95% CI:6-18%), respectively, for normal D-dimer either without or with RVO, 22.9% (95% CI: 14-33%) and 25.9% (95% CI: 18-35%), respectively, for abnormal D-dimer, either without or with RVO. When compared with normal D-dimer without RVO, the multivariate HR for recurrence was similar for abnormal D-dimer either with RVO (4.76 - 95% CI:1.78-12.8) or without RVO (4.3-95%:1.56-11.88). Abnormal D-dimer at one month after OAT withdrawal is an independent risk factor for recurrent VTE, while RVO at the time of OAT withdrawal, either with normal or abnormal D-dimer after one month, does not influence the risk of recurrence.     

Deficient t-PA release and elevated PA inhibitor levels in patients with spontaneous or recurrent deep venous thrombosis

The fibrinolytic system was investigated in 120 patients with spontaneous or recurrent deep vein thrombosis (DVT) without any known organic disease able to explain by itself the occurrence of a thrombosis and without any known defect of antithrombin III, Heparin Cofactor II, Protein C, or Protein S. The assays included: Euglobulin fibrinolytic activity (EFA), tissue-type plasminogen activator related antigen (t-PA-Ag) and plasminogen activator inhibitor activity (PA inhibitor), which were measured before and after 10 min of venous occlusion (V.O.). On the basis of the results, the patients could be classified in 3 groups: good responders with an at least two-fold increase of EFA after venous occlusion (n = 76), poor responders with a lesser increase of EFA due to deficient release of t-PA (n = 12), and poor responders with a normal t-PA release but an increased level of PA-Inhibitor (n = 32). The poor responders due to deficient t-PA release (10% of total) had a higher incidence of recurrence of deep vein thrombosis, than the other groups (p less than 0.01). An overall correlation was found between the level of PA-Inhibitor activity and the triglyceride level (r = 0.40, p less than 0.01), suggesting that these elevations may be due to a common cause, at least in some of the patients. It is concluded that a poor fibrinolytic response to venous occlusion occurs in 35 percent of DVT patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Poor fibrinolytic response to venous occlusion by different criteria in patients with deep vein thrombosis.

Five criteria for poor response to a 20 min venous occlusion test were applied to 58 patients 3 months or more after acute deep vein thrombosis (DVT). The criteria were arbitrarily defined as the last 5 percentiles of response distributions in an age- and sex-matched healthy control group of 51 subjects. The criteria were: 1. euglobulin clot lysis time after venous occlusion greater than or equal to 140 min; 2. t-PA activity after venous occlusion less than or equal to 0.04 IU/ml; 3. increase in t-PA antigen above resting value less than or equal to 2-fold; 4. ratio between t-PA antigen increase and resting PAI activity less than or equal to 0.5 ng/IU; 5. PAI activity after venous occlusion greater than or equal to 6 IU/ml. The last criterion of poor response was the only one that was significantly more frequently reached by patients than by controls: 28% (p less than 0.005) of all DVT patients and 35% (p less than 0.005) of the subgroup with idiopathic DVT (N = 34) were found to be poor responders. The percentage of poor responders according to the other four criteria was 7-11% in all patients and 9-15% in the subgroup with idiopathic DVT and thus was not significantly higher than in controls (5% by definition). It was concluded that residual PAI activity after venous occlusion might be a useful criterion for prospective studies on recurrence of DVT.     

Ovarian vein thrombosis: incidence of recurrent venous thromboembolism and survival

For patients with ovarian vein thrombosis (OVT), neither the rate of recurrence nor the expected survival are well established. Clarification of these natural history data would aid in defining the optimal management. We studied all female patients with OVT seen at the Mayo Clinic between 1990 and 2006. Survival, recurrent venous thrombosis rates, and prothrombotic factors were compared to a randomly selected group of 114 female patients with lower extremity venous thrombosis (DVT). Patients with OVT (n = 35; mean age 44.8 +/- 17.9 years) were significantly more likely to be under hormonal stimulation (48%), have an underlying malignancy (34%), experienced recent pelvic infection (23%) or undergone recent surgery (20%), compared to DVT patients. During a mean follow-up period of 34.6 +/- 44.3 months, three patients suffered three recurrent venous thrombi (event rate: three per 100 patient years of follow-up). This recurrence rate was comparable to patients with lower extremity DVT (2.2 per 100 patient years). Recurrent thrombosis involved the contralateral ovarian vein, left renal vein, and inferior vena cava. The five-year mortality rate for OVT patients was 43% compared to 20% for DVT patients (p = 0.08). All OVT deaths were cancer related. Survival was greater in OVT patients without cancer compared to those with active cancer (p < 0.0001). In conclusion, venous thromboembolism recurrence rates are low and comparable to lower extremity DVT. Therefore general treatment guidelines for lower extremity DVT may be applicable. Poor survival rates in OVT are principally governed by the presence of malignancy.     

Physical activity in patients with deep venous thrombosis: a systematic review

Objectives

We performed a systematic review to assess the benefits or risks of physical activity in patients with an acute or previous DVT of the leg.

Data sources

PubMed, EMBASE and Science Citation Index were searched without language restrictions up to July 2007. Bibliographies of retrieved articles and personal files were also searched.

Review methods

Randomized trials and prospective cohort studies that included patients with acute or previous DVT, described an exercise intervention or exercise exposure, and described any related clinical outcome were selected. Data were independently extracted by 2 investigators.

Results

Seven randomized trials and two prospective observational studies were included. Early exercise, compared with bed rest, was associated with a similar short-term risk of pulmonary embolism in patients with acute DVT and led to more rapid resolution of limb pain. In patients with acute DVT, a 6 month daily walking program led to similar degrees of vein recanalization and improvement in quality of life as controls. In patients with previous DVT, 30 min of vigorous treadmill exercise did not worsen venous symptoms and improved calf muscle flexibility; a 6 month exercise training program improved calf muscle strength and pump function; and high levels of physical activity at one month tended to be associated with reduced severity of postthrombotic symptoms during the subsequent 3 months.

Conclusions

Early walking exercise is safe in patients with acute DVT and may help to reduce acute symptoms. Exercise training does not increase leg symptoms acutely in patients with a previous DVT and may help to prevent or improve the postthrombotic syndrome.     

Factor VII-activating protease in patients with acute deep venous thrombosis

Factor VII-activating protease (FSAP) is involved in haemostasis and inflammation. FSAP cleaves single chain urokinase-type plasminogen activator (scu-PA). The 1601GA genotype of the 1601G/A polymorphism in the FSAP gene leads to the expression of a FSAP variant with reduced ability to activate scu-PA, without affecting the ability to activate coagulation Factor VII (FVII). Previous studies have investigated the association of the 1601GA genotype with incidence and progression of carotid stenosis and deep venous thrombosis (DVT). The present study is the first to evaluate the potential association between the FSAP phenotype and DVT.We studied the association between the 1601G/A polymorphism, FSAP activity, FSAP antigen, Factor VIIa (FVIIa), prothrombin fragment 1 + 2 (F1 + 2), and C-reactive protein (CRP) in plasmas of 170 patients suspected for DVT. FSAP genotypes were equally distributed in patients with (n = 64) and without DVT (n = 106), (P = 0.94). The 1601GA genotype was associated with significant reduction of FSAP activity (P < 0.001) and FSAP antigen levels (P = 0.04). Patients with DVT showed significantly higher FSAP activity (P = 0.008), FSAP antigen (P = 0.003), and F1 + 2 levels (P < 0.001) than patients without DVT. The association between the FSAP measures and DVT disappeared when adjusted for CRP levels. F1 + 2 correlated positively to FSAP antigen (P = 0.01), while FVIIa-levels were comparable in patients with and without DVT.We conclude that even though FSAP measures are significantly increased in patients with acute DVT, alterations in the scu-PA activating properties of FSAP are presumably not markedly involved in the development of acute DVT, and that the association between FSAP and DVT disappears after adjustment for CRP.     

Fibrinolytic variables in patients with recurrent venous thrombosis: a prospective cohort study

To determine whether fibrinolytic testing predicts recurrent venous thrombosis, we have performed a prospective cohort study in which 303 patients with a first episode of venous thromboembolism underwent comprehensive fibrinolytic testing while receiving oral anticoagulants, and after anticoagulants had been discontinued. They were then followed for up to 3 years for recurrent venous thrombosis. No systematic differences in the levels or activity of type 1 plasminogen activator inhibitor (PAI-1), tissue plasminogen activator (tPA) or euglobulin clot lysis times were detected between patients who did, or did not, suffer recurrent thrombosis. There were also no differences in these variables when patients whose initial thrombosis was idiopathic were compared to patients whose thrombosis occurred in the setting of a known thrombotic risk factor. Based on these results, neither measuring fibrinolytic parameters in patients with venous thromboembolism, nor modification of treatment based on the results of such testing, are justified. Our study also confirms that patients with idiopathic venous thromboembolism have a high risk of recurrence.     

D-dimer and residual vein obstruction as risk factors for recurrence during and after anticoagulation withdrawal in patients with a first episode of provoked deep-vein thrombosis

D-dimer and residual venous obstruction (RVO) have been separately shown to be risk factors for recurrent venous thromboembolism (VTE) after a first episode of unprovoked proximal deep-vein thrombosis (DVT). It was the objective of this study to assess the predictive value of D-dimer and residual vein obstruction (RVO), alone and in combination, for recurrence after provoked DVT of the lower limbs. A total of 296 consecutive patients with a first episode of symptomatic provoked proximal DVT were evaluated at a university hospital in Bologna, Italy. On the day of anticoagulation withdrawal (T0), RVO was determined by compression ultrasonography. D-dimer levels (cut-off: 500 ng/ml) were measured at T0 and after 30 ±10 days (T1). The main outcome was recurrent VTE during a two-year follow-up. D-dimer was abnormal in 11.6% (32/276) and 31% (85/276) of subjects at T0 and at T1, respectively. RVO was present in 44.8% (132/294) of patients. Recurrence rate was 5.1% (15/296; 95% confidence interval [CI]: 3-8%; 3% patient-years; 95% CI: 2-5 %). An abnormal D-dimer either at T0 or at T1 was associated with an adjusted hazard ratio (HR) for recurrence of 4.2 (95% CI:1.2-14.2; p=0.02) and 3.8 (95%CI: 1.2-12.1; p=0.02), respectively, when compared with normal D-dimer. The HR for recurrence associated with RVO was not significant, and RVO did not increase the recurrence risk associated with an abnormal D-dimer either at T0 or T1. In conclusion, an abnormal D-dimer during vitamin K antagonist (VKA) treatment or at one month after VKA withdrawal is a risk factor for recurrence in patients with provoked DVT, while RVO at the time of anticoagulation withdrawal is not.     

A randomized management study of impedance plethysmography vs. contrast venography in patients with a first episode of clinically suspected deep vein thrombosis

OBJECTIVES: In this randomized management study, we examined the safety of withholding anticoagulation on the basis of negative impedance plethysmography (IPG) compared to negative contrast venography (CV) in symptomatic patients with a first episode of clinically suspected deep vein thrombosis (DVT), and we determined the impact of the limitations of IPG or CV on their clinical utility. METHODS: Patients at a university teaching hospital presenting with a first episode of clinically suspected DVT were randomized to one of two management strategies at study entry: (1) IPG: if positive, confirmatory CV was performed. If CV was positive, anticoagulants were administered, if CV was negative, anticoagulants were held. If negative, IPG was repeated serially and if it remained negative, anticoagulants were held (n = 165). (2) CV: if positive, anticoagulants were administered, if negative, anticoagulants were held (n = 159). The negative predictive value (NPV) of IPG and CV, positive predictive value (PPV) of IPG, and the failure rate of each strategy were assessed. RESULTS: Among IPG patients, 28 of 37 with positive IPG initially or during serial testing and evaluable CV had confirmed DVT (PPV 76%; 95% confidence interval, CI [62%, 90%]). DVT was diagnosed during serial testing in 2.1% of patients with initially negative IPG who completed testing. The NPV overall of negative IPG was 98.3%. During follow-up, two patients in the IPG group (1.2%) and two patients in the CV group (1.3%) developed venous thromboembolism (VTE). Death during follow-up occurred in 11% of IPG patients compared to 6% of CV patients (P =.13) The investigation strategy failed in 25% of IPG patients and in 14% of CV patients. CONCLUSIONS: Our findings demonstrate that the two diagnostic strategies we studied are equivalent methods for ruling out DVT in patients with a first episode of suspected DVT. The PPV of IPG was too low to permit its use alone as a test to rule in DVT. Both strategies had surprisingly high failure rates.     

High prevalence of recurrent thrombosis in subsets of cancer patients with isolated gonadal vein thrombosis: A single center retrospective study

Purpose

Cancer patients are a high-risk population for venous thromboembolism (VTE); the natural history of gonadal vein thrombosis (GVT) occurring in cancer patients is not well described in the medical literature.

Methods

Utilizing a software program the computerized tomographic scan reports of patients at a single cancer center from January 1, 2004 to June 30, 2011 were searched for the term GVT. Patients included in this analysis had a diagnosis of cancer, an isolated GVT (i.e. no evidence of thrombosis at another site), no symptoms referable to the GVT, and at least six months of follow-up information. All subsequent recurrent VTE events were confirmed by imaging studies.

Results

196 cancer patients with GVT were identified. The majority of patients in this analysis had metastatic disease (118, 61.2%) as well as active cancer (167, 85.2%). Twenty patients (10.8%) developed recurrent VTE (median follow-up 14.5 months); median time to recurrent VTEs was 5.5 months (range 0–19 months). When considering only patients with without a recent history of gynecologic surgery, VTE recurrence rates were 14.3%. Active cancer was the only risk factor significantly associated with recurrent VTE (P = 0.047).

Conclusions

Based upon the patient’s risk factors for VTE, treatment of an incidentally detected GVT in cancer patients with anticoagulation, as per guidelines for other VTE sites, may be indicated in certain high risk subgroups, especially those patients with active cancer who have not had prior pelvic surgery.     

Clinical prediction of deep vein thrombosis in patients with leg symptoms

Symptoms and clinical signs individually are inaccurate for the diagnosis of DVT. However, when assessing patients with leg symptoms, clinicians have access to additional information, such as whether or not DVT risk factors are present that could improve the accuracy of clinical judgment. The purpose of this study was to identify which clinical variables best predict DVT, and to use these variables to create a clinical prediction index for DVT. We studied 271 university hospital patients with a first episode of symptomatic, clinically suspected DVT. The prevalence of DVT was 27%, of which 71% were proximal. At baseline, information was collected on demographic features, comorbidity, and symptoms and signs. A Bayesian model selection strategy was used to estimate the logistic regression model that best predicted DVT. Male sex [OR = 2.8 (1.5, 5.1)], orthopedic surgery [OR = 5.4 (2.2, 13.6)], warmth [OR = 2.1 (1.2, 3.9)] and superficial venous dilation on exam [OR = 2.9 (1.4, 5.7)] were independent predictors of DVT. Using the model, a clinical prediction index that categorized patients into different levels of DVT risk was created, and was useful in a theoretical strategy aimed to limit the need for contrast venography in patients with suspected DVT, such that 96% of study patients could have avoided contrast venography. This index should be evaluated prospectively in other patient populations.     

Fibrinolytic response to venous occlusion for 10 and 20 minutes in healthy subjects and in patients with deep vein thrombosis

Tissue plasminogen activator (t-PA) activity, t-PA antigen (t-PA:Ag) and t-PA inhibitor activity (PAI) were measured at rest and during venous occlusion (VO) for 10 and 20 min in 21 healthy subjects and 80 patients with venous thromboembolic disease. The expected t-PA release was seen in the controls. However, the release was found to be nonlinear and 63% of the t-PA:Ag was released during the last 10 min of VO. Defective release of t-PA:Ag and/or t-PA activity was found in 25 patients (31%). Three subgroups could be identified: 10 patients (13%) with low t-PA:Ag release (PRI), 6 patients (8%) with a high basal level of PAI (PR II) and 9 patients (11%) who had only low t-PA activity after VO. Using VO for 10 min only, 60%, 83% and 44% of the patients in PR I, PR II and PR III, respectively, were recognized. Using VO for 20 min only, the figures were 80%, 83% and 89%, respectively. The use of t-PA values corrected for the haemoconcentration during VO influenced the patients' classification as poor responders to only a minor degree. It is concluded that in screening for hypofibrinolysis VO is needed for at least 20 min, but that the sensitivity of the test increased by using VO for both 10 and 20 min.