Normal Venograms Research Articles

Intracranial Hypertension in a Transgender Man.

Case description of recurrent idiopathic intracranial hypertension (IIH) in a transgender man on gender-affirming hormone therapy. Case report. A 24-year-old transmasculine patient (assigned female at birth), with a body mass index (BMI) of 37.3, presented with headaches, transient visual obscurations (TVOs), pulsatile tinnitus, Frisén 5 papilledema, and scotomas. He was diagnosed with IIH after normal magnetic resonance imaging (MRI) and magnetic resonance venogram (MRV), an elevated opening pressure of 27 cm water, and normal cerebrospinal fluid studies. IIH resolved with acetazolamide and optic nerve sheath fenestration (ONSF). He then started gender-affirming testosterone therapy and was on this for 20 months when his headaches, pulsatile tinnitus, TVOs, and Frisén 3 papilledema recurred at a BMI of 31. Brain MRI and MRV were normal. Opening pressure was elevated at 31 cm. water. Acetazolamide 4 g/day did not improve the papilledema, thus a left ONSF was repeated resulting in eventual resolution of the IIH. Several reports have been published of IIH development in patients receiving testosterone therapy. Hormone prescribers for gender affirmation may wish to screen for visual loss and optic nerve edema in patients undergoing testosterone therapy, which may also stimulate appetite weight gain.

Abnormally hyperdense intracranial vessels on non-contrast computed tomography scan simulating dural venous sinus thrombosis in a case with high hematocrit

Abnormal hyperdensity of intracranial blood vessels on non-contrast computed tomography scan (NCCT) may be found in cases with raised hematocrit. This finding not only simulates the appearance of a contrast enhanced CT scan but also may mimic dural venous sinus thrombosis. Here we report a case of child with Fallot's tetralogy and central cyanosis who showed abnormally hyperdense intracranial vessels on NCCT of head simulating the appearance of dural venous sinus thrombosis. The absence of suggestive clinical findings in the child, hyperdensity of intracranial arteries as well as the veins and a normal magnetic resonance venogram (MRV) suggested that the raised hematocrit is responsible for such appearance.

Venous thromboembolism prophylaxis: do trial results enable clinicians and patients to evaluate whether the benefits justify the risk? proceedings of an ad hoc working group meeting

Venous thromboembolism prophylaxis: do trial results enable clinicians and patients to evaluate whether the benefits justify the risk? proceedings of an ad hoc working group meeting

Central venous obstruction and clinical predictors in patients with permanent pacemaker

This study investigated the proportion of silent venous obstruction in patients who underwent pacemaker or lead reimplantation for various reasons. We also investigated independent predictors or risk factor of venous obstruction in this patient population. Seventy-three patients who underwent pacemaker pulse generator and/or lead reimplantation in our institution between 2007 and 2010 were enrolled for this retrospective case-control study. Prior to procedure, patients underwent ipsilateral venography. Patients' venographies were classified as non-significant obstruction (stenosis ≤70%, including normal venogram), significant obstruction (stenosis >70%) and complete obstruction. Continuous and categorical data were compared with Mann-Whitney U test and Chi-square statistics respectively. Logistic regression analysis was used to identify independent predictors of venous obstruction. Complete or significant silent central venous obstruction (CVO) proportion was detected as 9.5% (n=7). Basal characteristics of patients with or without CVO were comparable. Significantly increased pacemaker pocket erosion incidence (57% vs 0%, p=0.001, in groups with and without CVO respectively) and significantly higher mean pacemaker age (15.3 ± 10.2 years vs 10.4 ± 5.1 years, p=0.047, in groups with and without CVO respectively) were found in group with CVO. Pacemaker pocket erosion (OR 3.00; 95% CI 1.024-9.302; p=0.001), higher pacemaker age (OR 1.33; 95% CI 1.026-1.733; p=0.02) were found as independent CVO predictors in multiple logistic regression analysis. Correlation analysis also revealed a significant correlation between previous or current pacemaker pocket erosion and CVO (r=0.80, p=0.001). Ipsilateral venography is a useful procedure prior to pacemaker or lead reimplantation to detect CVO. In addition to the increased pacemaker age, current or past history of erosion and infection at pacemaker pocket are probable clinical conditions related to CVO. These clinical conditions create a predisposition to CVO with unknown mechanisms, according to the results of this preliminary study.

Progression of venous pathology after pacemaker and cardioverter-defibrillator implantation: A prospective serial venographic study

Background and aims. Prospective data on development of venous obstruction after electrode implantation are limited. We performed a prospective study on 150 patients undergoing first pacemaker implantation.Methods. Venographies at base-line and 6 months postimplantation in all patients, 50 patients included into a long-term follow-up of a mean of 2.4 years after implantation.Results. At 6 months 14% had obstructions, but only 1 patient (0.7%) developed acute symptomatic upper extremity venous thrombosis. Pulmonary embolism (PE) was encountered in 5 (3.3%).After 6 months only 2 patients experienced pain in ipsilateral arm, but none had edema of arm, neck or head, or clinical PE. The 5 patients with total venous occlusion (TVO) at 6 months had no localized symptoms. Late venographic abnormalities developed in 5 (10%) patients: 4 TVOs and 1 stenosis. Two of the new lesions developed among 25 patients with normal 6-month venograms. Overall, TVO was detected in 9 of 150 patients. No factors emerged as independent predictors of total occlusion in multiple regression analysis.Conclusions. TVO is not uncommon after pacemaker implantation, and mostly occurs without any localizing symptoms. Most venous lesions seem to develop during the first months postimplantation, but late and unpredictable TVO may also occur.

Screening for Deep Vein Thrombosis and Pulmonary Embolism in Outpatients with Suspected DVT or PE by the Sequential Use of Clinical Score: A Sensitive Quantitative D-Dimer Test and Noninvasive Diagnostic Tools

The requirement for a safe diagnostic strategy should be based on an overall posttest incidence of venous thromboembolism (VTE) of less than 1% during 3-month follow-up. The negative predictive value (NPV) during 3 months of follow-up is 98.1 to 99% after a normal venogram, 97 to 98% after a normal compression ultrasonography (CUS), and > 99% after serial CUS testing. Serial CUS testing is safe but 100 CUS must be repeated to find one or two CUS positive for deep vein thrombosis (DVT), which is not cost-effective and indicates the need to improve the diagnostic workup of DVT by the use of clinical score assessment and D-dimer testing. The NPV varies from 97.6 to 99.4% for low clinical score followed by a negative SimpiRED test, indicating the need for a first CUS. The NPV is 98.4 to 99.3% for a normal rapid enzyme-linked immunosorbent assay (ELISA) VIDAS D-dimer test result (< 500 ng/mL) irrespective of clinical score. The NPV is more than 99% for a negative CUS followed by either a negative SimpiRED test or an ELISA VIDAS test result of < 1000 ng/mL without the need to repeat a second CUS within 1 week. The sequential use of a sensitive, rapid ELISA D-dimer and clinical score assessment will safely reduce the need for CUS testing by 40 to 60%. Large prospective outcome studies demonstrate that with one negative examination with complete duplex color ultrasonography (CCUS) of the proximal and distal veins of the affected leg with suspected DVT, it is safe to withhold anticoagulant treatment, with a negative predictive value of 99.5%. This may indicates that CCUS is equal to serial CUS or the combined use of clinical score, D-dimer testing, and CUS. Pulmonary angiography is the gold standard for segmental pulmonary embolism (PE) but not for subsegmental PE. A normal perfusion lung scan and a normal rapid ELISA VIDAS D-dimer test safely excludes PE. Helical spiral computed tomography (CT) detects all clinically relevant PE and a large number of alternative diagnoses in symptomatic patients with suspected PE and can replace both the ventilation perfusion scan and pulmonary angiography to safely rule in PE and to rule out PE with an NPV of > 99%. The combination of clinical assessment, a rapid ELISA VIDAS D-dimer, followed by CUS will reduce the need for helical spiral CT by 40 to 50%.

A Clinical Probability Assessment and D-dimer Measurement Should Be the Initial Step in the Investigation of Suspected Venous Thromboembolism

I access to noninvasive investigation and a declining tolerance for diagnostic uncertainty has resulted in increasing numbers of patients who are referred with suspected venous thromboembolism (VTE), all of whom require objective testing to confirm or exclude the diagnosis. Hence, the proportion of patients with suspected VTE in whom the diagnosis is confirmed has fallen progressively from 30 to 35% in the 1970s and 1980s,1–3 to around 15 to 25% in the last decade.4–6 Indeed, prevalences of 10% have been reported.7 This trend is not inappropriate for a potentially fatal disorder that can be effectively treated, but it has important resource implications. The potential value of plasma d-dimers (d-ds) as an exclusionary test for VTE in an era of increasing numbers of negative imaging test results has been appreciated for more than a decade. However, although outcome studies performed in the last 5 years have shown that a negative d-d test result can be used to minimize the need for serial ultrasound testing in patients with suspected deep vein thrombosis (DVT),8,9 and to reduce the need for additional imaging in patients with suspected pulmonary embolism (PE) and nondiagnostic ventilation/perfusion (V/Q) scan results,10,11 their role as an exclusionary first-line test has been uncertain. The clinically useful d-d tests can be divided into two main groups that have important differences in performance characteristics. Rapid enzyme-linked immunosorbent assays (ELISAs) have very high sensitivity but low specificity, while modern latex agglutination tests tend to be somewhat less sensitive but more specific. More recently, highly sensitive latex agglutination tests have been developed, but they tend to have lower specificities so that their performance characteristics tend to resemble those of the ELISA assays. In the absence of an assay that is both highly sensitive and specific, two possible strategies for the initial use of d-d as an exclusionary tool are apparent. First, an assay chosen for high specificity could be used in combination with an additional factor such as low pretest probability (PTP), which identifies a subgroup with a low disease prevalence. This strategy is based on the concept that a test that had a sensitivity of, say, 90%, could not be used by itself to exclude VTE safely, but might be perfectly adequate when targeted to a subgroup of patients with a prior probability of, for example, only 5%. Second, an assay chosen for high sensitivity could be employed either as a stand-alone exclusionary test or in combination with an additional factor that identifies the major subgroup of patients in whom prevalence of VTE is not particularly high (ie, those with low or intermediate PTP). The proper evaluation of these approaches requires clinical outcome studies that will investigate the safety of withholding imaging and treatment in patients with suspected VTE on the basis of these strategies, together with an assessment of their exclusionary efficiency. Ideally, patients categorized as being “VTE-negative” should have a 3-month event rate similar to that observed in patients with suspected DVT who have normal venogram or serial *From the Department of Haematology, Guy’s & St. Thomas’ Trust, London, UK. Received February 25, 2002; revision accepted May 29, 2003. Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (e-mail: permissions@chestnet.org). Correspondence to: James Kelly, Department of Haematology, Fourth Floor, North Wing, St. Thomas’ Hospital, London, UK SE1 7EH; e-mail: jameskelly@northbrookfm.fsnet.co.uk opinions/hypotheses

Catheter-related deep venous thrombosis in children with hemophilia

AbstractCentral venous catheters (CVCs) are a common adjunct to hemophilia therapy, but the risk of CVC-related deep venous thrombosis (DVT) in hemophiliacs is not well defined. In a previous study, 13 patients with CVCs had no radiographic evidence of DVT. However, recent abstracts and case studies demonstrate that DVT does occur. Therefore, this study sought to determine the frequency of DVT in children with hemophilia and long-term CVCs and to correlate venographic findings with clinical features. All hemophilia patients with tunneled subclavian CVCs in place for 12 months or more were candidates for evaluation. Patients were examined for physical signs of DVT and questioned about catheter dysfunction. Contrast venograms were obtained to identify DVT. Fifteen boys with severe hemophilia were evaluated, including 9 from the initially studied group of 13. Eight patients had evidence of DVT, 5 of whom previously had normal venograms. Five of 15 patients had clinical problems related to the CVC, all of whom had DVT. Four of 15 patients had suggestive physical signs; 3 had DVT. The mean duration of catheter placement for all patients was 57.5 months (range, 12-102 months). For patients with DVT, the mean duration was 66.6 ± 7.5 months, compared to 49.5 ± 7.2 months for patients without DVT (P = .06). No patient whose CVC was in place fewer than 48 months had an abnormal venogram. Many hemophilia patients with CVCs develop DVT of the upper venous system, and the risk increases with duration of catheter placement.

Evaluation of duplex ultrasonography versus other investigations in the diagnosis of ‘venous aetiology’ in patients with leg ulcers

Abstract Background The aim was to compare duplex imaging, venography, foot volumetry and air plethysmography in patients with healed leg ulcers considered to be caused by venous disease to discover whether duplex scanning alone could confirm a venous aetiology. The importance of isolated reflux in a segment of the deep system below a competent valve was assessed. Methods A total of 125 patients with 153 healed leg ulcers was examined. An Acuson (Mountain View, California, USA) scanner was used to detect reflux lasting for more than 0·5 s in the deep, superficial and calf perforating veins; the findings were compared with those obtained with ascending venography, foot volumetry and air plethysmography. Results Thirteen legs showed no reflux on duplex imaging, but ten of these had abnormal foot volumetry and 12 had abnormal plethysmography. Venography showed post-thrombotic change in 26 legs, but there was evidence of deep venous scarring in only six on duplex ultrasonography. Eight of 75 legs with a normal venogram had ‘complete’ (thigh-to-calf) deep reflux on duplex imaging. Forty-five legs showed segmental deep reflux on duplex imaging, of which 29 had associated perforating vein incompetence. Mean half-refilling times on foot volumetry were 8·46 s for femoral and 5·84 s for popliteal reflux, compared with 3·84 s in the 33 patients who had thigh-to-calf reflux (P &amp;lt; 0·05). Conclusion Absence of reflux in all venous segments on duplex imaging does not exclude a venous aetiology for ulceration. Segmental femoral and popliteal incompetence on duplex imaging is usually associated with other sites of valvular incompetence, but depresses calf function less than thigh-to-calf reflux.

Out-of-Hospital Prophylaxis With Low-Molecular-Weight Heparin in Hip Surgery: The French Study—Venographic Outcome at 35 Days

Out-of-Hospital Prophylaxis With Low-Molecular-Weight Heparin in Hip Surgery: The French Study—Venographic Outcome at 35 Days

Deep Venous Thrombosis and Lupus Anticoagulant

A definite evidence in favour of an association of deep-vein thrombosis (DVT) with lupus anticoagulant (LA) in patients free from systemic lupus erythematosus is still lacking. In a case-control study, LA was determined in 176 consecutive outpatients who underwent phlebography because of the first episode of clinically suspected DVT of lower limbs. The association between DVT and LA was described using odds ratios (OR). Contrast venography confirmed the clinical suspicion in 59 patients (33.5%). LA was detected in 5 of the 59 patients with DVT (8.5%), and in none of the 117 subjects with normal venogram (P = 0.007). The OR for having an acute DVT in patients with LA was 10.7 (95% CI: 1.2-94.2). LA is significantly associated with DVT in symptomatic patients. Further studies are needed to establish the clinical implications of this association.

Reductions in tissue plasminogen activator and thrombomodulin in blood draining veins damaged by venous access devices

A frequent complication of venous access devices (VADs) is axillary-subclavian venous thrombosis. To study this problem we have compared blood drawn through VADs with peripheral blood samples in a group of oncology patients with venographically demonstrated venous damage (N = 14) and a group with normal venograms (N = 21). The samples were assayed for a battery of proteins believed to be involved in thrombogenesis. After approximately six weeks of catheterization the venographically abnormal patients had significantly less thrombomodulin (P = 0.0055) and significantly higher PAI:tPA (P = 0.022) in catheter-drawn samples as compared with the venographically normal group. Although the data are inconclusive, it is hypothesized that these changes resulted from local endothelial injury.

Follow‐up study of patients with clinically suspected deep venous thrombosis and a normal venogram

To evaluate the clinical course in patients with clinically suspected deep venous thrombosis (DVT) of the leg and a normal venogram. Prospective study over 15 months with a follow-up of 4-12 (median 8.6) months after a normal venogram. A questionnaire survey was performed at follow-up. Information from general practitioners and medical records was reviewed. An alternative diagnosis was established at presentation and at the time of follow-up. The Department of Internal Medicine in a Danish university hospital. A total of 133 consecutive out-patients referred with clinical suspicion of DVT and a normal venogram. The state of symptoms at follow-up. The frequency of referrals to hospitals and contacts with general practitioners or medical specialists in the follow-up period. Clinical diagnoses provided at presentation and at follow-up. The follow-up response rate was 78% (n = 104). The symptoms were still present at follow-up in 53 (51%) patients. More than half of the patients had been referred to medical facilities for the same disorder. Diagnoses could be established in 93 (70%) of the 133 patients at presentation and in 119 (89%) at follow-up. The majority of patients with clinical signs and symptoms of a DVT and a normal venogram may require a follow-up surveillance programme to ensure correct diagnosis and adequate treatment. Further studies are recommended to confirm our results and to assess the cost-effectiveness.

When Can Treatment Be Withheld in Patients With Suspected Pulmonary Embolism?

OBJECTIVE TESTS are needed to confirm or exclude the diagnosis of venous thromboembolism because the accuracy of the clinical diagnosis is less than 50%.^1,2The most accurate tests available for the diagnosis of pulmonary embolism and deep venous thrombosis (DVT) are pulmonary angiography¹and contrast venographhy.³With technically adequate studies, false-negative tests are rare. Therefore, a normal pulmonary angiogram is sufficient evidence to withhold treatment in patients with suspected pulmonary embolism,⁴and a normal venogram precludes the need for therapy in patients with suspected DVT.⁵ Unfortunately, pulmonary angiography and venography are expensive, invasive tests that have associated morbidity, and are not available at all hospitals. Therefore, noninvasive tests play a critical role in the evaluation of patients with suspected venous thromboembolism. Two noninvasive tests for deep venous thromboembolism, impedance plethysmography (IPG) and ultrasonography have an excellent correlation with venograms in patients with proximal DVT of

Colour flow mapping in the diagnosis of the calf deep vein thrombosis

This prospective trial was organized to evaluate further the role of colour flow Doppler ultrasound techniques in the diagnosis of deep vein thrombosis (DVT) with particular reference to the isolated calf lesion. In 100 patients ultrasound was compared against the recognized gold standard of ascending venography. Fifty venograms were positive for DVT compared with 49 on ultrasound, a sensitivity of 98%. The specificity of ultrasound for DVT in the 50 patients without DVT on venography was 100%. Forty-five venograms demonstrated calf thrombus with varying proximal extent. Sixteen proved to be isolated calf lesions and these were all identified by ultrasound (100% sensitivity and specificity respectively for isolated calf DVT). In five of these isolated calf thrombus cases, results suggested that ultrasound better diagnosed the presence of thrombus. Ultrasound diagnosed significant pathology in 13 of the normal venogram patients giving an overall diagnostic yield of 62% as compared to 50% at venography.

Comparison of Real-Time B-Mode Ultrasonography and Doppler Ultrasound with Contrast Venography in the Diagnosis of Venous Thrombosis in Symptomatic Outpatients

In a prospective study, we compared real-time B-mode ultrasonography, using the simple criteria of common femoral and popliteal vein compressibility (Compression US), and Doppler ultrasound, using a standardized technique (Doppler US), with contrast venography in 158 consecutive outpatients symptomatic for deep-vein thrombosis of the lower limbs (DVT). For proximal vein thrombosis, the sensitivities documented for Compression US and Doppler US were 100% (95% CI: 90% to 100%) and 89% (95% CI: 76% to 96%), respectively. This difference is not statistically significant (p = 0.056). For all thrombi (including isolated calf-vein thrombosis), however, the sensitivity of Compression US was significantly higher than that of Doppler US (95% and 76%, respectively; p < 0.04). Compression US was normal in all patients with normal venogram (specificity, 100%; 95% CI: 95% to 100%), while Doppler US was abnormal in two patients with normal venogram (specificity, 98%; 95% CI: 92% to 100%). The specificities of the two tests did not differ significantly. The results of our comparison suggest that Compression US is superior to Doppler US in the detection of DVT in symptomatic outpatients.

Duplex Ultrasonography for the Detection of Deep Vein Thrombi After Total Hip or Knee Arthroplasty

The usefulness of real-time duplex ultrasonography (DU) as a screening test for deep vein thrombosis (DVT) in high-risk patients remains uncertain. To determine the sensitivity and specificity of DU for the detection of DVT, the authors prospectively studied 178 consecutive patients after total hip (n = 113) or total knee (n = 66) arthroplasty. The deep veins from the inguinal ligament to the ankle were examined first by continuous wave and then by pulsed Doppler signals as needed with real-time gray-scale ultrasound imaging using the criteria of vein noncompressibility to define DVT. Ascending contrast venography was performed within twelve hours after DU studies. Venograms and DU were interpreted independently. DU was attempted on 177 lower extremities (2 patients refused) but was judged adequate for interpretation for only 145 (82%). Venography could not be performed for 28 lower extremities and was technically inadequate for 8 studies. The primary analysis included 119 examinations for which adequate DU and ascending venograms were interpreted. DU was positive in 17 of 27 lower extremities with DVT (23 calf, 4 proximal) diagnosed by venography (sensitivity = .63; 95% confidence interval [CI] = .42 to .81), and DU was negative in 85 of 92 lower extremities with normal venograms (specificity = .92; 95% CI = .85 to .97). A secondary analysis of 81 prospectively collected anatomically complete DU studies demonstrated a sensitivity of .80 (95% CI = .56 to .94) and a specificity of .90 (95% CI = .80 to .96).(ABSTRACT TRUNCATED AT 250 WORDS)

Failure of thrombin-antithrombin III complexes in the diagnosis of deep vein thrombosis.

Plasma thrombin-antithrombin III (T-AT) complexes are reputed to be an indirect manifestation of thrombin generation, and a role for their determination in the diagnosis of deep vein thrombosis (DVT) has been advocated. In order to evaluate the accuracy of T-AT complexes assay for DVT diagnosis, in 166 consecutive outpatients with clinical suspicion of the disease, plasma concentration of T-AT complexes was measured immediately before venography by means of an enzyme-linked immunosorbent assay kit. The result of the T-AT complexes assay was elevated in 29 of the 48 patients with DVT (sensitivity, 60%). The T-AT complexes levels were within the normal range in 104 of the 118 patients with normal venograms (specificity, 88%). The positive and the negative predictive value were 67% and 85%, respectively. The authors conclude that the T-AT complexes assay is of little value for the diagnosis of DVT in outpatients.

Predictive factors of effectiveness of streptokinase in deep venous thrombosis

In a prospective study, 174 patients (118 women and 56 men, average age 44 years, range 14 to 82) with proximal extensive thrombosis received streptokinase (100,000 U/hour) for an average of 2.8 days (range 0.5 to 7) through the catheter of a temporary caval fitter. Twenty-seven of 45 (60%) patients with nonocclusive clots were completely free of clots at the second phlebography versus 17 of 116 (14%) with occlusive clots (p < 0.001). Among nonocclusive clots, proximal ones (caval, iliac and femoral) were more easily lysed than popliteal clots (88 of 116 [76%] vs 26 of 58 [45%]; p < 0.001). In 41 of 132 (31%) patients, a daily injection of contrast medium through the filter-carrying catheter enabled the observation of a clot in the filter, which was lysed by streptokinase. Seventy patients with follow-up >2 years (median 34 months) were examined clinically. Nineteen of 22 (86%) patients with venograms free of clots at discharge were free of clinical sequelae versus 16 of 48 (33%) without normal venograms (p < 0.001). It is concluded that: (1) in the case of occlusive clots, only a few patients were normalized after streptokinase; (2) proximal nonocclusive clots were most effectively lysed; (3) when venograms were free of clots at discharge, the majority of patients did not have venous sequelae at follow-up; and (4) embolie migration seems to occur frequently with streptokinase.

Prevention of Deep Vein Thrombosis following Total Hip Replacement by Low Molecular Weight Heparinoid

We assessed the safety and efficacy of the novel low molecular weight heparinoid Lomoparan (Org 10172) for the prevention of deep-vein thrombosis in patients undergoing elective total hip replacement in a randomized, placebo-controlled, double-blind trial in 197 consecutive patients. The heparinoid (750 anti-factor Xa-units, s.c., b.i.d.) was administered to 97 patients and 99 patients received placebo. Study medication was started preoperatively and continued for 10 days. Efficacy was assessed by bilateral phlebography at day 10, postoperatively. The incidence of deep-vein thrombosis was 56.6% and 15.5% respectively in the placebo and heparinoid treated patients (incidence reduction: 74%; P less than 0.001). This reduction was observed both for proximal-vein thrombosis (25% to 8%; P less than 0.005) and isolated calf-vein thrombosis (31% to 7%; P less than 0.001). No major hemorrhage was observed. The number of red-cell units transfused and drain-fluid loss were comparable for the two study groups. Six patients in the heparinoid group and none in the control group developed minor wound hematomas (P less than 0.05). During an 8-week post-discharge follow-up period three patients with a normal venogram at day 10 developed clinically apparent venous thromboembolism, which was confirmed by objective testing. All three patients belonged to the heparinoid-treated group. We conclude that 750 anti-factor Xa units Org 10172 s.c. twice daily starting preoperatively is safe and effectively reduces early deep-vein thrombosis following elective total hip replacement. Further studies on the incidence of post-discharge thromboembolism are required.