Impedance plethysmography using the occlusive cuff technique in the diagnosis of venous thrombosis.

Impedance plethysmography using the cuff technique has been compared with venography in 346 consecutive patients with suspected venous thromboembolism. The limbs were classified according to the venographic results as no thrombosis, proximal (popliteal, femoral, or iliac) vein thrombosis, and calf thrombosis. A discriminant analysis was performed. The impedance plethysmographic result was normal in 386 of 397 limbs which were normal on venography, a specificity of 97%, and abnormal in 124 of 133 limbs which showed proximal vein thrombosis, a sensitivity of 93%. Seventy-three of 88 limbs with calf vein thrombi and a normal impedance plethysmographic result. The sensitivity in 29 limbs with asymptomatic proximal vein thrombosis was 83%. Impedance plethysmography is an accurate method for detecting proximal vein thrombosis but has limitations which include the possibility of false positive results due to arterial insufficiency and muscle tension.     

Distal deep-venous thrombosis: diagnostic and therapeutic issues

PURPOSE: Compression ultrasonography is the reference test for the diagnosis of distal deep venous thrombosis of lower limbs. However, the ways it is performed and the related treatments are very heterogeneous between various countries. CURRENT KNOWLEDGE AND KEY POINTS: In USA, Canada and Netherlands, compression ultrasonography is restricted to proximal limbs considering that this test is inadequate to explore the distal veins. The strategy consisting of a clinical approach, including the clinical probability and/or a follow-up ultrasonography has demonstrated its efficacy and safety (extension rate to proximal veins of 1.2% at three months and absence of fatal pulmonary embolism). In France, Italy and Spain, lower limb ultrasonography testing includes the examination of calf veins in a so called "complete testing". This procedure leads to the diagnosis of a large number of distal deep venous thrombosis (45-56%) among the 14 to 36% of deep vein thrombosis diagnosed in the setting of clinical suspicion. Recent diagnosis strategy studies have shown that both strategies are effective, but the complete ultrasound strategy doubles the number of anticoagulation treatments. Justification of inappropriate anticoagulation is not evident owing to the relatively low risk of proximal venous-thrombosis extension, the rate of severe hemorrhagic events at three months and the cost excess. FUTURE PROSPECTS AND PROJECTS: Prospective comparative clinical trials are necessary in distal-venous thrombosis and ongoing Cactus study addresses this therapeutic dilemma.     

Value of real time B mode ultrasound imaging in the diagnosis of deep vein thrombosis of the lower limbs

In order to determine the value and the role of real time B mode ultrasound imaging (USI) in the diagnosis of deep vein thrombosis (DVT) of the lower limbs, it was compared to bilateral contrast ascending venography used as a standard of reference, prospectively and systematically on 430 patients suspected of having DVT or pulmonary embolism. A total of 854 limbs were thus studied double blindly both by the two methods. The results corresponded in 95% of the legs with a sensitivity of 98% and a specificity of 95% for USI. Isolated thrombosis of the calf were detected in 91% of the legs and proximal thrombosis were in 100% in this series whatever their topography and extent should be and whatever be the degree of obstruction of the vein. The discrepancies between the two methods are related to: (a) Vein thrombosis especially located in the calf, in the soleal sinuses and the gastrocnemius with in most cases the direct image of the thrombus detected by U.S.I. more often than by venography, provided that the technique and the equipment are appropriate. (b) The absence of visualisation of venous segments with venography which is not specific of venous thrombosis. These veins when non affected by the thrombosis are not filled by the contrast medium if located above an occluded ilio-femoral or ilio-caval junction or when they are the site of extrinsic compression. The direct imaging of the vein and the surrounding structures obtained with USI enhances the diagnostic sensitivity and specificity and provides precision of the exact extension of the thrombosis. Venous study by USI is always coupled with the Doppler.(ABSTRACT TRUNCATED AT 250 WORDS)     

Short-duration prophylaxis against venous thromboembolism after total hip or knee replacement: a meta-analysis of prospective studies investigating symptomatic outcomes

BACKGROUND: The prevalence of asymptomatic deep vein thrombosis diagnosed by venography after hip or knee replacement remains high despite 7 to 10 days of anticoagulant prophylaxis. However, the risk of symptomatic events in such patients is unclear. We performed a meta-analysis to provide reliable estimates of the risk of symptomatic venous thromboembolism occurring within 3 months of hip or knee replacement in patients who received short-duration (7-10 days) anticoagulant prophylaxis. METHODS: The MEDLINE, EMBASE, and Cochrane databases were searched from January 1993 to March 2001, supplemented by a manual search of bibliographies and conference abstracts, to identify prospective studies of patients undergoing hip or knee replacement who received short-duration prophylaxis (ie, 7-10 days of fixed-dose low-molecular-weight heparin or adjusted-dose warfarin, with a target international normalized ratio of 2.0-3.0). Studies were classified as clinical outcome studies if the outcome was symptomatic venous thromboembolism or as venographic outcome studies if the outcome was asymptomatic deep vein thrombosis diagnosed after bilateral venography. RESULTS: There were 4 clinical outcome studies with 6089 patients who had 3 months of follow-up, and 13 venographic outcome studies with 7080 patients who had venography 7 to 10 days after surgery. In clinical outcome studies, the 3-month incidence of nonfatal venous thromboembolism was 3.2% (95% confidence interval [CI], 2.0%-4.4%), and the 3-month incidence of fatal pulmonary embolism was 0.10% (95% CI, 0.02%-0.20%). The postprophylaxis incidence of nonfatal venous thromboembolism was 2.2% (95% CI, 1.4%-3.0%), and the incidence of fatal pulmonary embolism was 0.05% (95% CI, 0%-0.12%). The postprophylaxis incidence of symptomatic venous thromboembolism was higher after hip than after knee replacement (2.5% vs 1.4%; P=.02). In venographic outcome studies, the prevalence of deep vein thrombosis (total and proximal) was higher after knee than after hip replacement (total: 38.8% vs 16.4%; P<.001; proximal: 7.6% vs 3.8%; P<.001). CONCLUSIONS: In patients who undergo hip or knee replacement and receive short-duration anticoagulant prophylaxis, symptomatic nonfatal venous thromboembolism will occur in about 1 of 32 patients and fatal pulmonary embolism will occur in about 1 of 1000 patients within 3 months of the surgery. Although the prevalence of asymptomatic deep vein thrombosis is more than 2-fold higher after knee replacement than after hip replacement 7 to 10 days after surgery, in the subsequent 3 months, symptomatic venous thromboembolism is more likely to occur after hip replacement.     

Complete compression ultrasound for the diagnosis of venous thromboembolism

PURPOSE OF REVIEW: Since its first appearance in the 1980s, venous ultrasound has increasingly gained interest of both clinicians and researchers. However, a majority of authors currently are convinced that venous ultrasound has inherent limitations that preclude it from safely ruling out distal deep vein thrombosis (DVT) in symptomatic patients and from detecting proximal and distal DVT accurately in asymptomatic patients. The aim of this review is to present recent lines of evidence indicating that venous ultrasound has developed beyond these limitations. RECENT FINDINGS: The major development does not arise from technical progress of imaging but from standardizing the examination procedure. The most efficient protocols now focus on B-mode sonography only but extend the examination to the paired deep calf veins and the calf muscle veins. For such an examination protocol, the term complete compression ultrasound (CCUS) has been coined. Interobserver variability of CCUS resembles that of venography, as do the technical failure rates. By means of a CCUS protocol, the diagnostic work-up of patients with suspected DVT can be simplified significantly. Studies in asymptomatic patients indicate that CCUS has the potential to generate valid data in prevalence and incidence studies and in intervention trials. SUMMARY: Complete compression ultrasound protocols are ready for implementation into clinical practice for diagnosing patients with symptomatic DVT. Research has already benefited from CCUS and benefits further with an increasing number of CCUS-driven trial designs. However, the value of a CCUS protocol critically depends on sound training and on strict compliance with all its details.     

Thromboses veineuses profondes distales isolées des membres inférieurs : épidémiologie et prise en charge

Isolated distal deep-vein thromboses (DVT) are infra-popliteal DVT without involvement of proximal veins or pulmonary embolism (PE). They can affect deep calf (tibial anterior, tibial posterior, or peroneal) or muscular (gastrocnemius or soleal) veins. They represent half of all lower limbs DVT. Proximal and distal DVTs differ in terms of risk factor profile, proximal DVT being more frequently associated with chronic risk factors and distal DVT with transient ones. Their natural history (rate of spontaneous proximal extension) is debated leading to uncertainties on the need to diagnose and treat them with anticoagulant drugs. In the long term, the risk of venous thromboembolic recurrence is lower than that of proximal DVT and their absolute risk of post-thrombotic syndrome is unknown. French national guidelines suggest treating with anticoagulants for 6 weeks a first episode of isolated distal DVT provoked by a transient risk factor and treating for at least 3 months unprovoked or recurrent or active cancer-related distal DVT. The use of compression stockings use is suggested in case of deep calf vein thrombosis. Ongoing therapeutic trials should provide important data necessary to establish an evidence-based mode of care, especially about the need to treat distal DVT at low risk of extension with anticoagulants.     

Light reflection rheography as a noninvasive screening test for deep venous thrombosis.

STUDY OBJECTIVE: To determine if light reflection rheography is a useful screening tool for the diagnosis of proximal leg deep venous thrombosis. DESIGN: Light reflection rheography was compared with duplex ultrasonography and/or contrast venography on emergency patients being evaluated for proximal leg deep venous thrombosis. SETTING: University hospital emergency department. TYPE OF PARTICIPANTS: Seventy-five ED patients being evaluated for acute leg deep venous thrombosis. INTERVENTIONS: Seventy-five patients being evaluated for clinically suspected deep venous thrombosis had light reflection rheography performed on the involved extremity immediately before duplex ultrasonography and/or contrast venography. Duplex ultrasonography and/or contrast venography was the definitive diagnostic test. MEASUREMENTS AND RESULTS: Seventy-five patients had light reflection rheography performed, 72 had duplex ultrasonography, 19 had contrast venography, three had contrast venography alone, and 16 had both duplex ultrasonography and contrast venography. A comparison of light reflection rheography with duplex ultrasonography and/or contrast venography reveals that 39 light reflection rheography examinations were true-negative, 17 were true-positive, one was false-negative, and 18 were false-positive. The sensitivity of light reflection rheography for the detection of proximal leg deep venous thrombosis is 94.4% (95% confidence interval [CI], 72.7-99.9%), the negative-predictive value is 97.5% (95% CI, 86.8-99.9%), the specificity is 68.4% (95% CI, 54.8-80.1%), and the positive-predictive value is 48.6% (95% CI, 31.4-66%). CONCLUSION: Light reflection rheography proved to be an excellent screening tool for emergency patients with the clinical suspicion for an acute proximal leg deep venous thrombosis. A normal light reflection rheography examination was 97.5% accurate as a negative predictor. That is, a normal light reflection rheography excluded the diagnosis of proximal leg deep venous thrombosis when compared with duplex ultrasonography and/or contrast venography when the duplex ultrasonography and/or contrast venography showed no evidence of proximal leg deep venous thrombosis. An abnormal light reflection rheography does not equate to an acute leg deep venous thrombosis as the specificity was only 68.4%. An abnormal light reflection rheography mandates further diagnostic studies such as duplex ultrasonography and/or contrast venography to confirm a diagnosis of proximal leg deep venous thrombosis.     

Diagnosis of deep venous thrombosis. A prospective study comparing duplex scanning to contrast venography

Duplex scanning has been proposed as a safe alternative to contrast venography for diagnosing deep venous thrombosis, but its accuracy has not been proved. In this prospective, double-blind study of 47 patients, the sensitivity and specificity of duplex scan criteria were determined relative to contrast venography for lower extremity deep venous thrombosis. Criteria considered to show the presence of deep venous thrombosis included visualization of thrombus (T), absence of spontaneous flow by Doppler ultrasonography (F), absence of phasicity of flow with respiration (P), and incompressibility of the vein with probe pressure (VC). When analyzed individually, the variables T and F had low sensitivities (50% and 76%) but high specificities (92% and 100%). VC had low values for both (79% and 67%, respectively). The best single variable was P (sensitivity and specificity = 92%). The best combinations of variables were T+P (sensitivity = 95%, specificity = 83%), T+F+P (sensitivity = 95%, specificity = 83%), F+P (sensitivity and specificity = 92%), and F+T (sensitivity = 92%, specificity = 87%). The low specificity of vein incompressibility was secondary to cases in which normal veins were difficult to compress in the thigh. All false-negative cases were from isolated calf vein thrombi. We conclude that isolated criteria from duplex scanning should not be used to diagnose deep venous thrombosis. In cases of suspected calf vein thrombosis, repeat duplex examination should be obtained in 3-4 days to determine the most appropriate therapy. In equivocal cases of proximal vein thrombosis, a contrast venogram should be obtained.     

Serial limited versus single complete compression ultrasonography for the diagnosis of lower extremity deep vein thrombosis

The diagnostic approach to deep vein thrombosis (DVT) has evolved during the last 3 decades. Contrast venography has been replaced by noninvasive tests. Compression ultrasonography (CUS) is currently the most widely used diagnostic test. Whereas CUS has a high accuracy for proximal DVT (thrombosis of the popliteal and more proximal veins), it has been shown to lack sensitivity and specificity for distal DVT. Ultrasonography can either be limited to the proximal veins and repeated within 1 week (serial limited CUS) or extended to both proximal and distal veins and performed on one occasion (single complete CUS). Both strategies are reliable diagnostic options for the management of patients with suspected DVT. The main limitation of proximal CUS is the need to repeat the test once in patients with initial negative findings. Conversely, complete CUS detects many distal DVTs for which systematic anticoagulation therapy is debatable and exposes patients to potentially unnecessary anticoagulation. Incorporation of D-dimer testing and clinical pretest probability assessment in the diagnostic algorithm is beneficial because it allows excluding DVT without the need for diagnostic imaging in about a third of patients.     

Looking for deep vein thrombosis in suspected pulmonary embolism

Pulmonary embolism (PE) and deep vein thrombosis are two facets of the same disease, that is, venous thromboembolism (VTE). In patients with angiographically proven PE, the prevalence of proximal deep vein thrombosis by venography is around 70%. The sensitivity of compression ultrasonography (US) for the diagnosis of acute VTE in patients with a suspicion of PE is between 40 and 60%, with a high specificity (96 to 100%). Taking into account the 20 to 30% prevalence of PE in a population consulting for suspicion of this disease, the first line use of compression US will allow the diagnosis of acute VTE in half of patients with confirmed PE, that is, in 10 to 15% of patients addressed for suspicion of PE. In outpatients, the first line use of D-dimers which will exclude acute VTE in one-third of the initial population will slightly increase the reliability of compression US as a first imaging test. New tools of looking for deep vein thrombosis, such as computed tomographic venography coupled with computed tomographic pulmonary angiography, could become an interesting approach in the diagnostic strategy of PE, but require adequate evaluation in prospective studies.     

Comparison of near-infrared spectroscopy with air plethysmography in detection of deep vein thrombosis.

BACKGROUND: As a noninvasive screening test, air plethysmography (APG) is a reliable and frequently used modality in the detection of deep vein thrombosis (DVT). Although APG is highly sensitive for the diagnosis of proximal DVT, its sensitivity for identifying calf DVT is poor. Near-infrared spectroscopy (NIRS) is a new modality which can be used to evaluate venous retention during walking. The purpose of this study was to investigate the diagnostic value of NIRS for the detection of DVT, particularly isolated calf DVT, in comparison with APG. METHODS: Fifty limbs of 39 consecutive patients with clinically suspected DVT were studied. All patients were examined by venography and APG. Patients also underwent a treadmill-walking test with simultaneous NIRS. Deoxygenated hemoglobin was continuously measured by NIRS during exercise. The ambulatory venous retention index obtained from serial DeoHb changes was calculated in each patient. RESULTS: Venography demonstrated DVT in 35 limbs, confined to the calf in 9 limbs, and with the involvement of a proximal deep vein with thrombi in 26. The overall sensitivity of NIRS and APG was 97% (34/35) and 80% (28/35), respectively. NIRS was more sensitive than APG for detecting isolated calf DVT (89% [8/9] and 22% [2/9], respectively), while both tests identified proximal DVT in all limbs. CONCLUSIONS: NIRS is a highly sensitive method for the diagnosis of haemodynamically significant DVT. NIRS may become a useful screening test because of its reliability in detecting calf vein thrombi that cannot be identified by APG.     

Venous ultrasound in current angiology practice

From a 3,000 patients study, estimation of venous system by B-mode Imaging coupled with directional Doppler velocimetry is reported. Concordance in 85% of correlations between ultrasonic venography and conventional phlebography for deep vein calf thrombosis is promising. Real time venous echography provides reliable diagnosis with simple, repetitive and non-invasive control of deep veins system. Significant visualization of superficial veins system provides for non-occlusive disease or thrombotic lesions a new approach and eventual enlargement of surgical indications.     

Value and place of real-time ultrasonic diagnosis combined with continuous-wave Doppler in the diagnosis and follow-up of thromboembolic disease

The authors compared the results of real time ultrasound imaging and continuous wave Doppler (Echography-Doppler with bilateral venography and ilio-cavography in the diagnosis and the follow-up of deep venous thrombosis (D.V.T.). Diagnosis of D.V.T. The value of echography-Doppler (ED) compared to venography is studied on 297 patients (590 legs) suspected of D.V.T. (221) or pulmonary emboli (76). The two methods give concording results in 95% (563/590). Discrepancies (27) are more often located in distal veins. If we refer to venography as the gold standard, sensitivity of ED is 98% (236/242) and specificity is 95% (327/344). Other diagnosis are possible: hematoma (9), extrinsic compression (15), Baker's cyst (4), muscular problems (3)... Topographic value Sensitivity in isolated calf vein thrombosis is 90% (54/60 are detected, 22 are bilateral). 4/6 false negatives are located in the presumable healthy legs. Sensitivity in proximal D.V.T. is excellent 100% (182 D.V.T. with 28 bilateral). The upper extremity of the thrombus is located exactly by ED whatever the topography (35 in the inferior vena cava, three of them beyond the renal veins), the degree of obstruction (partially occluded veins: 32), and even if it's extended or not (27). Follow-up of D.V.T. Assessment of the results in 80 patients under treatment is identical with the two methods, whatever the topography, the degree of obstruction and the evolution of thrombosis. E.D. predictive value in therapeutic efficiency is discussed according to the evolution data in 260 patients. Screening of D.V.T. ED is compared to venography (13) and/or Fibrinogen test (15), in 23 patients (46 legs) with high risk of thrombosis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Non-invasive methods for vascular studies in the diagnosis of deep venous thrombosis

The sonographic diagnosis of deep venous thrombosis must be made up of a functional continuous wave Doppler study of the whole deep venous system of the limbs, including leg veins, as well as saphenous veins. Then, high resolution B-mode real time sonography is used for the detection of direct (echogenic thrombus) or indirect (incompressible vein) signs of thrombosis. This noninvasive approach offers a good sensitivity (about 96%) and a high level of specificity (about 98%). Moreover, B-mode sonography can ensure the differential diagnosis (hematoma, extrinsic compression...) in most cases. So, X-Ray venography is required only when an interventional therapy is planned (thrombectomy, fibrinolysis, inferior vena cava interruption...), or when the noninvasive techniques are not able to show the upper limit of the thrombosis (especially for iliac veins or inferior vena cava), or when there is still a doubt about deep venous thrombosis. Therefore, the number of X Ray venographies can be consistently reduced, thus decreasing both cost and risks.     

The diagnostic approach to deep venous thrombosis

Accurate diagnosis of deep vein thrombosis is important because untreated deep vein thrombosis can cause death or permanent impairment and because effective treatments are available. The approach to the diagnosis of deep vein thrombosis varies because of differences in local resources and expertise. Duplex ultrasonography with venous compression is the preferred initial test for the majority of outpatients who present with symptoms and signs that suggest acute deep vein thrombosis. Clinical outcome studies have shown the safety of withholding anticoagulants when two compression ultrasonography examinations are negative over a 5- to 7-day period. Alternative strategies, for example, combining clinical scores and D-dimer with compression ultrasonography, may also prove effective. In unusual circumstances, venography or even magnetic resonance imaging may be necessary.     

Real-time ultrasound in the diagnosis of acute deep venous thrombosis of the lower extremity

One hundred twenty-six patients with clinically suspected acute deep venous thrombosis of the lower extremity (DVT) were examined comparatively with ultrasound and venography. In total, 174 lower extremity venograms were obtained. Ultrasonic examinations were performed on patients in the supine position. The venous segments were evaluated almost exclusively with transversal scanning. In the thigh, the only criterion for DVT was the reduced or absent compressibility of the venous lumen when gently compressed with the transducer. In the calf, normal unobstructed veins can usually not be viewed in the supine patient, whereas thrombotic veins appear as sonolucent, incompressible channels. Eight-three of the 174 lower extremity venograms were positive for DVT. In the majority of cases (53 of 83) the thrombotic process had involved two or more segments in combination. The sites of involvement of the different venous segments were distributed as follows: 24 occlusions of the common femoral vein, 52 of the superficial femoral vein, 56 of the popliteal vein, and 71 of the calf veins. Ultrasound had a sensitivity of 100% for thrombosis of the common femoral vein, 96% for the superficial femoral veins, 98% for the popliteal vein, and 93% for the calf veins. For the entire lower extremity, in regard to the diagnosis of thrombosis, the overall sensitivity was 95%. In 90% the extension of the occlusion was foreseen correctly. In no cases were false-positive results reported. Thus the overall specificity was 100%. The authors conclude that real-time ultrasound is a highly accurate method for the diagnosis of DVT of the lower extremity. It is the only indirect method capable of evaluating the venous system of the thigh, as well as that of the calf, with high accuracy. It should be the first choice of diagnostic imaging method in the diagnosis of deep venous thrombosis of the lower extremity.     

In-Hospital Risks and Management of Deep Venous Thrombosis According to Location of the Thrombus

BackgroundWhether deep venous thrombosis involving the pelvic veins or inferior vena cava is associated with higher in-hospital mortality or higher prevalence of in-hospital pulmonary embolism than proximal or distal lower extremity deep venous thrombosis is not known.MethodsThis was a retrospective cohort study based on administrative data from the Nationwide Inpatient Sample, 2016, 2017. Patients hospitalized with a primary diagnosis of deep venous thrombosis at known locations were identified by International Classification of Diseases-10-Clinical Modification codes.ResultsIn-hospital all-cause mortality with deep venous thrombosis involving the inferior vena cava in patients treated only with anticoagulants was 2.2% versus 0.8% with pelvic vein deep venous thrombosis (p<0.0001), 0.7% with proximal deep venous thrombosis (p<0.0001) and 0.2% with distal deep venous thrombosis (p<0.0001). Mortality with anticoagulants was similar with pelvic vein deep venous thrombosis compared with proximal lower extremity deep venous thrombosis, 0.8% versus 0.7% (p=0.39). Lower mortality was shown with pelvic vein deep venous thrombosis treated with thrombolytics than with anticoagulants, 0% versus 0.8% (p<0.0001). In-hospital pulmonary embolism occurred in 11% to 23%, irrespective of the site of deep venous thrombosis.ConclusionPatients with deep venous thrombosis involving the inferior vena cava had higher in-hospital mortality than patients with deep venous thrombosis at other locations. Pelvic vein deep venous thrombosis did not result in higher mortality or more in-hospital pulmonary embolism than proximal lower extremity deep venous thrombosis. The incidence of in-hospital pulmonary embolism was considerable with deep venous thrombosis at all sites.     

腔内超声在髂静脉受压综合征中的应用及研究进展

髂静脉受压综合征(IVCS)是指髂静脉受压、且腔内存在异常黏连结构所引起的下肢和盆腔静脉回流障碍性疾病,又称May-Thurner综合征或Cockett综合征.其不仅是造成下肢静脉瓣膜功能不全和浅静脉曲张的原因之一,也是静脉血栓好发的潜在因素.目前临床中的主要检查方式包括彩色多普勒超声(CDFI)、计算机断层扫描静脉造...     

Comparison of the oral direct thrombin inhibitor ximelagatran with enoxaparin as prophylaxis against venous thromboembolism after total knee replacement: a phase 2 dose-finding study

BACKGROUND: Up to one third of patients who undergo total knee replacement develop deep vein thrombosis after surgery despite receiving low-molecular-weight heparin prophylaxis. Ximelagatran is a novel direct inhibitor of free and clot-bound thrombin. METHODS: We performed a randomized, parallel, dose-finding study of 600 adults undergoing elective total knee replacement at 68 North American hospitals to determine the optimum dose of ximelagatran to use as prophylaxis against venous thromboembolism after total knee replacement. Patients received either ximelagatran twice daily by mouth in blinded fixed doses of 8, 12, 18, or 24 mg or open-label enoxaparin sodium, 30 mg, subcutaneously twice daily, starting 12 to 24 hours after surgery and continuing for 6 to 12 days. We measured the 6- to 12-day cumulative incidence of symptomatic or venographic deep vein thrombosis, symptomatic pulmonary embolism, and bleeding. RESULTS: A total of 594 patients received at least 1 dose of the study drug; 443 patients were evaluable for efficacy. Rates of overall venous thromboembolism (and proximal deep vein thrombosis or pulmonary embolism) for the 8-, 12-, 18-, and 24-mg doses of ximelagatran were 27% (6.6%), 19.8% (2.0%), 28.7% (5.8%), and 15.8% (3.2%), respectively. Rates of overall venous thromboembolism (22.7%) and proximal deep vein thrombosis or pulmonary embolism (3.1%) for enoxaparin did not differ significantly compared with 24-mg ximelagatran (overall difference, -6.9%; 95% confidence interval, -18.0% to 4.2%; P=.3). There was no major bleeding with administration of 24 mg of ximelagatran twice daily. CONCLUSION: Fixed-dose, unmonitored ximelagatran, 24 mg twice daily, given after surgery appears to be safe and effective oral prophylaxis against venous thromboembolism after total knee replacement.     

Postthrombotic syndrome after hip or knee arthroplasty: a cross-sectional study

BACKGROUND: Although the incidence of the postthrombotic syndrome (PTS) has been addressed in patients with symptomatic deep vein thrombosis (DVT), less information is available on the incidence in patients who develop asymptomatic DVT after major hip or knee arthroplasty. OBJECTIVES: To determine whether symptomatic PTS occurs more frequently in patients who develop DVT after hip or knee arthroplasty than those who are free of DVT and to provide an estimate of the incidence of PTS in patients who had undergone major hip or knee arthroplasty and had proximal DVT, distal (calf) DVT, or no DVT. DESIGN AND SETTING: A cross-sectional study conducted at the Hamilton Health Sciences Corporation, Hamilton, Ontario, and the Academic Medical Centre, Amsterdam, the Netherlands. SUBJECTS AND METHODS: Two hundred fifty-five subjects who had undergone major hip or knee arthroplasty 2 to 7 years previously and had routine predischarge venography showing proximal DVT (n = 25), distal DVT (n = 66), or no DVT (n = 164) were enrolled from March 1993 through December 1998. The presence of symptomatic PTS confirmed by the presence of objectively confirmed venous valvular incompetence was ascertained. RESULTS: The rates of PTS were low and not significantly different among the 3 subgroups: 1 (4.0%, 95% confidence interval [CI] = 0.1%-20.4%) of 25 patients with proximal DVT, 4 (6.1%, 95% CI = 1.7%-14.8%) of 66 patients with distal DVT, and 7 (4.3%, 95% CI = 1.7%-8.6%) of 164 patients with no DVT. CONCLUSIONS: Symptomatic PTS is an uncommon complaint after major hip or knee arthroplasty. Patients who develop postoperative proximal or distal DVT and who receive 6 to 12 weeks of anticoagulant therapy are not predisposed to PTS.