Diagnostic value of compression ultrasonography and fibrinogen-related parameters for the detection of postoperative deep vein thrombosis following elective hip replacement: a pilot study

To determine their ability to diagnose postoperative deep vein thrombosis (DVT) D-dimer - by three methods -, fibrinogen degradation products (FgDP) and fibrinogen levels were measured in 68 consecutive patients before elective surgery for hip replacement and on postoperative day 1, 3, 6, and 10. All patients received prophylaxis and underwent compression real-time B-mode ultrasonography (C-US) on postoperative day 5 and 9, and bilateral ascending venography on day 10. Twenty-two out of 68 patients developed asymptomatic postoperative DVT, which was limited to the calf veins in 14 and involved the proximal veins in 8 patients. C-US was negative in all patients on day 5. On day 9, C-US sensitivity and specificity for proximal DVT were 63% (95% confidence interval: 26%-90% and 98% (89%-100%) respectively. Postoperative changes in the laboratory parameters evaluated were not different in patients with or without DVT until day 10. On day 10, mean D-dimer, FgDP and fibrinogen levels were significantly higher in patients with DVT than in those without DVT (p values between 0.006 and 0.032), but only D-dimer was higher with DVT involving two or more venous segments than with thrombosis involving one venous segment only (p < 0.05). Stepwise logistic regression analysis identified D-dimer and fibrinogen on day 10 as predictors of postoperative DVT. In a receiver operator curve and after weighing for the coefficients generated by logistic regression analysis, the combination of a latex photometric immuno-assay and of PT-derived fibrinogen yielded-at a cut-off value of 7.0 a sensitivity of 100% (73%-100%) and a specificity of 58% (39%-75%) for DVT, with a negative predictive value of 100% (78%-100%), a positive predictive value of 52% (32%-71%) and an overall accuracy of 71% (55%-83%). These results suggest that two simple, fast and reproducible tests may permit the identification of patients at low risk of having postoperative DVT and that a combination of sensitive laboratory assays and of the highly specific C-US may select patients requiring anticoagulant treatment. Efficacy and cost-effectiveness of this approach should be evaluated in large clinical management studies.     

Evaluation of a new rapid D-dimer assay for clinically suspected deep venous thrombosis (Liatest D-dimer)

In previous studies, enzyme-linked immunosorbent assays (ELISA) for plasma D-dimer analysis have demonstrated high sensitivity, suggesting their potential usefulness in excluding deep venous thrombosis (DVT). We evaluated the usefulness of a new D-dimer test (Liatest D-dimer) for suspected DVT in a prospective study of patients admitted to the hospital because of recent (not exceeding 1 week before admission) clinical signs. Contrast venography or compression ultrasonography or both were performed within 24 hours of admission. A new quantitative determination of D-dimer concentration using a suspension of microlatex particles coated with specific antibodies was tested. A standard plasma D-dimer ELISA measurement was also performed. Of 464 patients, 276 had a proven DVT (distal, 74; proximal, 202). For a cutoff level of 400 ng/mL, sensitivity of the Liatest method in the diagnosis of overall DVT was 94.6% (95% confidence interval, 92.0%-97.0%), and the specificity was 35% (95% confidence interval, 28%-42%). The sensitivity and negative predictive value were 98.5% and 95.6%, respectively, in the diagnosis of proximal DVT, but only 83.8% and 84.6%, respectively, in the diagnosis of distal DVT. This new rapid Liatest D-dimer assay seems to be highly sensitive and could replace the ELISA method in excluding patients with proximal DVT. Both methods provide lower sensitivity for distal DVT.     

Deep venous thrombosis: prediction by D-dimer?

The utility of D-dimer as an inexpensive, noninvasive method of diagnosing deep venous thrombosis (DVT) is debated. We sought to determine whether a qualitative D-dimer assay would have a high correlation with DVT in 65 hospitalized patients who were randomly referred for diagnosis of DVT by venous duplex and duplex Doppler ultrasonography. Patients were excluded from the study if they had any inflammatory, infectious, or malignant condition associated with elevation of D-dimer. The mean level of D-dimer in patients with DVT (16 of 65 patients) was 5,141 ng/mL, compared with 3,024 ng/mL in those without DVT, but there was considerable overlap between the two groups. No patients with a D-dimer level < 2,000 ng/mL had DVT. We conclude that the qualitative D-dimer assay is an excellent exclusionary test for DVT at levels less than 2,000 ng/mL. Limitations of the D-dimer assay and cost-effective issues are discussed.     

Comparison of immunofiltration assay of plasma D-dimer with diagnostic imaging in deep vein thrombosis

This prospective study was designed to assess the diagnostic sensitivity, specificity and negative predictive value of the NycoCard D-dimer plasma immunofiltration assay in patients with suspected deep vein thrombosis (DVT) confirmed by ultrasonography/venography. 84 medical patients were recruited: 43 patients (51%) had proven venous thrombosis, 33 by venography and 10 by ultrasonography. The sensitivity of NycoCard D-dimer in patients with DVT was 95.3%, the specificity was 22.0% and the negative predictive value was 81.8%. An algorithm including the NycoCard D-dimer test for the acute management of DVT is proposed. This would enable low-risk patients to be discharged early from hospital, without imaging or anticoagulant therapy.     

Minimally invasive cardiac surgery: current status and perspective

This study investigated the features of calf deep vein thrombosis (DVT) as a pulmonary embolic source. Fifty-eight lower limbs in 29 patients who were suspected of having DVT distal to the popliteal vein were screened by ultrasonography. Then, ascending venography was performed to confirm the diagnosis. Pulmonary embolism (PE) was diagnosed in suspected patients by use of pulmonary perfusion scanning or pulmonary angiography. Venography revealed calf DVT in 33 limbs in 28 patients. Of 28 patients, six had symptomatic PE. Thrombosis was found in the muscle veins in 18 limbs, the trunk veins in 11, and both veins in four. Isolated single vein thrombosis was found in the soleal vein in 14 limbs (42%), the posterior tibial vein in eight, the peroneal vein in two, and the gastrocnemius vein in two. The overall percentage of soleal vein thrombi was 61%. All six patients with symptomatic PE had isolated soleal vein thromboses. Calf DVT was a pulmonary embolic source when isolated thrombosis of the large soleal vein was more than 7 mm in diameter. Soleal veins were the most frequent and important location of calf DVT, suggesting that these were an occasional embolic source of critical PE.     

The role of venous ultrasonography in the diagnosis of suspected deep venous thrombosis and pulmonary embolism

This paper describes the role of venous ultrasonography in the diagnosis of suspected deep venous thrombosis and pulmonary embolism. Inability to compress the common femoral or popliteal vein is usually diagnostic of a first episode of deep venous thrombosis in symptomatic patients (positive predictive value of about 97%). Full compressibility of both of these sites excludes proximal deep venous thrombosis in symptomatic patients (negative predictive value of about 98%). In patients with suspected deep venous thrombosis or in those who present with suspected pulmonary embolism but have a nondiagnostic lung scan, the subsequent risk for symptomatic venous thromboembolism is very low (<2% during 6 months of follow-up) provided that ultrasonography of the proximal veins remains normal in the course of 1 week (suspected deep venous thrombosis) or 2 weeks (suspected pulmonary embolism). Anticoagulation and further diagnostic testing can usually be safely withheld in these situations. Venous ultrasonography is much less reliable for the diagnosis of asymptomatic, isolated distal, and recurrent deep venous thrombosis than for the diagnosis of a first episode of proximal deep venous thrombosis in symptomatic patients. Clinical evaluation of the probability of deep venous thrombosis or pulmonary embolism, preferably by using a validated clinical model, complements venous ultrasonographic findings and helps to identify patients who would benefit from additional (often invasive) diagnostic testing. Thus, venous ultrasonography is thought to be a very valuable test for the diagnosis and management of patients with suspected deep venous thrombosis or pulmonary embolism.     

Non-invasive diagnosis of venous thromboembolism in outpatients

BACKGROUND: We designed a simple and integrated diagnostic algorithm for acute venous thromboembolism based on clinical probability assessment of deep-vein thrombosis (DVT) or pulmonary embolism (PE), plasma D-dimer measurement, lower-limb venous compression ultrasonography, and lung scan to reduce the need for phlebography and pulmonary angiography. METHODS: 918 consecutive patients presenting at the emergency ward of the Geneva University Hospital, Geneva, Switzerland, and H?pital Saint-Luc, Montreal, Canada, with clinically suspected venous thromboembolism were entered into a sequential diagnostic protocol. Patients in whom venous thromboembolism was deemed absent were not given anticoagulants and were followed up for 3 months. FINDINGS: A normal D-dimer concentration (<500 microg/L by a rapid ELISA) ruled out venous thromboembolism in 286 (31%) members of the study cohort, whereas DVT by ultrasonography established the diagnosis in 157 (17%). Lung scan was diagnostic in 80 (9%) of the remaining patients. Venous thromboembolism was also deemed absent in patients with low to intermediate clinical probability of DVT and a normal venous ultrasonography (236 [26%] patients), and in patients with a low clinical probability of PE and a non-diagnostic result on lung scan (107 [12%] patients). Pulmonary angiography and phlebography were done in only 50 (5%) and 2 (<1%) of the patients, respectively. Hence, a non-invasive diagnosis was possible in 866 (94%) members of the entire cohort. The 3-month thromboembolic risk in patients not given anticoagulants, based on the results of the diagnostic protocol, was 1.8% (95% CI 0.9-3.1). INTERPRETATION: A diagnostic strategy combining clinical assessment, D-dimer, ultrasonography, and lung scan gave a non-invasive diagnosis in the vast majority of outpatients with suspected venous thromboembolism, and appeared to be safe.     

Reliability of five rapid D-dimer assays compared to ELISA in the exclusion of deep venous thrombosis

Studies measuring the fibrin degradation product D-Dimer (DD) using enzyme-linked immunosorbent assays (ELISA) in patients with venographically proven deep venous thrombosis (DVT) suggest that it is possible to exclude DVT when DD level is below a certain cut-off level. However, ELISA methods are time-consuming and not available in all laboratories. Different rapid latex-agglutination assays have been investigated, but their sensitivity is considerably lower. In the present study we compared the value of four novel latex DD tests (Tinaquant, Minutex, Ortho and SimpliRed) and one rapid ELISA (VIDAS) to a classical ELISA DD assay (Organon Mab Y18) in 132 patients suspected of DVT. The VIDAS, a new quantitative automated ELISA, had a sensitivity of 100% and a negative predictive value of 100% for both proximal and distal DVT at a cut-off level of 500 ng/ml. The Tinaquant assay, a new quantitative latex method, had a sensitivity of 99% and a negative predictive value of 93% for both proximal and distal DVT at a cut-off level of 500 ng/ml. For proximal DVT only, both assays had a sensitivity and negative predictive value of 100%. VIDAS and Tinaquant correlated well with ELISA (correlation of r = 0.96 and r = 0.98 respectively). Sensitivities of the semi-quantitative latex assays Minutex, Ortho and SimpliRed were considerably lower (77%, 51% and 61% respectively). These results suggest that VIDAS and Tinaquant may be used instead of ELISA DD in the exclusion of DVT. Tinaquant can be performed within 20 min and VIDAS within 35 min. Both assays might be used as a routine screening test and should be evaluated in large clinical management studies.     

Diagnosis of deep vein thrombosis in elderly hip-fracture patients by using the duplex scanning technique

To detect the incidence of preoperative and postoperative deep vein thrombosis (DVT) in elderly patients with hip fracture, 100 patients aged 65 years and older with either a subcapital or intertrochanteric hip fracture were evaluated by duplex beta-mode ultrasonography. Treatment was based on each scan result: if evidence for DVT was seen, the patient was therapeutically anticoagulated; lacking signs of DVT, patients were treated prophylactically. Before their operation, 77 patients (77%) had normal results of their scans, while DVT was diagnosed in 12 patients (12%). An additional 11 patients (11%) developed DVT after the operation. The total incidence of DVT in this series was 23%.     

Diagnosis of deep venous thrombosis and pulmonary embolism

Diagnostic evaluation in the patient with suspected deep vein thrombosis (DVT) and pulmonary embolism (PE) includes a clear correlation between clinical probability, test selection and test interpretation. Real-time B-mode ultrasound with color Doppler remains the imaging technique of choice in suspected DVT. The ventilation/perfusion (V/Q) lung scan is the preferred diagnostic modality in suspected PE. The D-dimer assay may be useful in excluding PA. New diagnostic techniques, including spiral computerized tomography may further modify the diagnostic algorithm.     

Total contact casts and removable cast walkers. Mitigation of plantar heel pressure

In this study we prospectively assessed the reliability of a new fibrin monomer assay in 106 outpatients with clinically suspected deep venous thrombosis of the lower limb. According to the results of the objective tests and using different cut-off points we calculated the sensitivity, specificity and negative predictive value of the fibrin monomer assay. The prevalence of deep vein thrombosis was 44.3% (31.1% proximal, 13.2% distal). Using a cut-off level of plasma fibrin monomer of 3.5 microg/ml, a sensitivity, specificity and negative predictive value of 100% (95% CI: 94-100%), 35.6% (95% CI: 23-48%) and 100% (95% CI: 86-100%), respectively, were obtained. The exclusion rate was 19.8% (95% CI: 12-27%) of all referred patients. These accuracy indices compared favourably with the respective results of a routine D-dimer ELISA used for comparison. Conclusion: This new fibrin monomer assay appears to be a reliable method for the exclusion of deep vein thrombosis in symptomatic outpatients.     

Pulmonary embolism in patients with intermediate probability lung scans: diagnosis with Doppler venous US and D-dimer measurement

PURPOSE: To test the usefulness of lower limb Doppler venous compression ultrasound (US) and serum D-dimer measurements in diagnosis of pulmonary embolism in patients in whom ventilation-perfusion (V-P) scans indicate intermediate probability of pulmonary embolism. MATERIALS AND METHODS: V-P scanning, pulmonary angiography, US, and D-dimer measurements were performed in 36 patients without known deep venous thrombosis but with intermediate probability of having a pulmonary embolism. RESULTS: Pulmonary angiography demonstrated pulmonary embolism in 15 (41%) of 36 patients. US demonstrated deep venous thrombosis in only two patients, both with pulmonary embolism. Sensitivity of US was only 13%, but specificity was 100%. Five (14%) of the 36 patients had normal (< 220 micrograms/L) D-dimer levels; none of the five had pulmonary embolism. Sensitivity and specificity of D-dimer values were 100% and 16%, respectively, with a negative predictive value of 100%. CONCLUSION: Combined D-dimer measurement and US were helpful in correctly diagnosing pulmonary embolism in only seven (20%) of 36 patients. Pulmonary angiography is still required to diagnose pulmonary embolism in the majority of patients.     

The development of valvular incompetence after deep vein thrombosis: a follow-up study with duplex scanning

PURPOSE: Duplex ultrasonography with distal cuff deflation was used to establish the physiologic reflux duration in different segments of the deep venous system in healthy individuals, and to document the occurrence of deep vein valve incompetence in patients after deep vein thrombosis (DVT). METHODS: Two hundred fifty-two vein segments in 42 legs of 21 healthy individuals and 160 deep vein segments in 27 patients with phlebographically documented DVT were examined with duplex scanning. RESULTS: The duration of reflux in healthy subjects was significantly shorter in distal deep vein segments. Ninety-five percent of the values were less than 0.88, 0.8, 0.8, 0.28, 0.2, and 0.12 seconds, respectively, for the common femoral, superficial femoral, deep femoral, popliteal, and posterior tibial vein (at midcalf and ankle level). The 95 percentile for reflux duration in the superficial venous system was 0.5 seconds for all vein segments, regardless of the location. No significant correlation was found between the reflux peak flow velocity and reflux duration (R = 0.6). The reflux peak flow velocity is therefore not useful as a parameter of the degree of reflux. The patient group was examined with an interval of 18 to 51 months (mean 34 months) after DVT. Forty-five percent of the initially affected segments showed valve incompetence at follow-up (n = 54); only three of 40 segments initially free from thrombus showed pathologic reflux at follow-up (p < 0.01). Reflux durations in most of the incompetent vein segments were two or more times the normal value of reflux duration. The highest prevalence of valve incompetence was found in the superficial femoral and popliteal vein segment (p < 0.01). None of the patients showed valve incompetence at all levels of the deep venous system. A significant (p = 0.04) relation was found between the extent of the initial thrombosis and the number of refluxing vein segments at follow-up, but no correlation was found between the extent of initial thrombosis and the late clinical symptoms (p = 0.16); clinical symptoms could not be related to the number of incompetent vein segments. CONCLUSIONS: Duplex scanning allows a good discrimination between physiologic and abnormal reflux duration and is an important tool in the evaluation of the postthrombotic limb. Early assessment after DVT may have prognostic value in individual patients.     

D-dimer levels in the cerebrospinal fluid: a marker of central nervous system involvement in neoplastic disease

D-dimer assay was performed on 145 cerebrospinal fluid (CSF) samples from patients with or without neoplastic diseases. Levels of D-dimers were significantly higher in carcinoma and lymphoid malignancies with clinical or biological evidence of central nervous system (CNS) involvement than in diseases without such complications. In one patient, serial determinations of D-dimers were well correlated with the appearance and disappearance of CNS involvement. Although this test is not specific for neoplastic affections, our data suggest that the measurement of D-dimers in CSF may be useful in the diagnosis of CNS involvement of neoplastic cells and in monitoring intrathecal therapy in patients with lymphoma, acute lymphoblastic leukaemia or carcinoma. In this study, the D-dimer assay was also positive in some non neoplastic diseases, but failed to differentiate subarachnoid haemorrhage from traumatic lumbar puncture.     

Rat gonadotropin-releasing hormone receptor expressed in insect cells induces activation of adenylyl cyclase

The diagnostic usefulness of measuring plasma D-dimers using the ELISA method and the latex agglutination test has been prospectively evaluated in 117 patients hospitalized for suspicion of acute venous thrombo-embolism (AVTE): pulmonary embolism was suspected in 80 patients and the remaining 37 had a suspicion of deep vein thrombosis of the lower limbs. The diagnosis of AVTE was confirmed in 50% of the patients, all of whom underwent gold standard invasive investigation i.e. pulmonary angiography and/or contrast venography. The sensitivity, specificity, negative predictive value and positive predictive value of a D-dimers plasma concentration exceeding 500 ng/ml for the diagnosis of AVTE were respectively 98, 58, 97 and 70% when using the ELISA method, and 86, 71, 84 and 75% when using the latex assay. In 47 patients whose lung scans yielded abnormalities of indeterminate probability of pulmonary embolism, the sensitivity of the ELISA method was very high (94%), but that of latex assay was low (67%). Our results demonstrate that measuring the plasma D-dimers by the latex assay should not be used in the diagnosis of AVTE. On the other hand, the ELISA method might be of great interest in the diagnostic strategy of AVTE, as a normal concentration of D-dimers rules out almost definitely the diagnosis of AVTE, and hence, spares from performing invasive investigations.     

Coagulation activation markers in the prediction of venous thrombosis after elective hip surgery

BACKGROUND: Despite prophylaxis, deep vein thrombosis (DVT) after hip surgery continues to occur frequently. Thus it would be helpful if before surgery patients at higher risk of DVT could be identified and more adequate prophylaxis given. As part of an international study on the prevention of DVT after total hip replacement, we investigated whether preoperative levels of three coagulation activation markers, prothrombin fragment F1 + 2 (F1 + 2), thrombin-antithrombin III complexes (TAT) and D-dimer, correlate with results of postoperative venography. METHODS: 159 patients undergoing total hip replacement were randomized to receive 10, 15 or 20 mg desirudin bid or 5000 IU unfractionated heparin tid immediately before surgery and then for 11 days, until bilateral venography was performed. Preoperative F1 + 2, TAT and D-dimer plasma levels were measured using ELISA procedures. As no difference among anticoagulant treatments or in the interaction between treatments and DVT was detected for any of the three variables, results are reported as pooled data. FINDINGS: The frequency of DVT was 18.8% in the low (0.75-1.33 nM) vs 65.7% in the high third of distribution (1.77-3.47 nM) of F1 + 2 (p < .001), 27.3% in the low (2.00-2.50 micrograms/l) vs 57% in the high third (5.10-61.00 micrograms/l) of TAT (p = .042), and 29.4% in the low (39-59 micrograms/l) vs 57.1% in the high third (129-651 micrograms/l) of D-dimer (p = .051). INTERPRETATION: Preoperative F1 + 2, TAT and D-dimer levels are associated with the risk of development of DVT after total hip replacement.     

How often is thrombolytic therapy of deep pelvic-leg venous thrombosis indicated?

BACKGROUND: For patients with deep vein thrombosis new thrombolytic regimes are being proposed and demand evaluation in controlled studies. We tested prospectively, how many patients in internal medicine are candidates for thrombolysis. PATIENTS AND METHODS: All available patients with the diagnosis of deep vein thrombosis (DVT) in lower extremities who were admitted to the service of internal medicine in a medium-sized hospital during one year were prospectively evaluated for the indication of fibrinolysis therapy according to the established criteria. RESULTS: A total of 62 patients were enrolled. Fibrinolysis was not proposed in 25 patients aged over 70 years nor in another 9 patients in whom the thrombosis was restricted to calf veins. Nine additional cases had a recurrence of DVT (n = 4) or a history of more than 14 days. Among the remaining 19 patients, fibrinolysis was not performed in 11 because of advanced malignomas (n =4) or other diseases (n = 3) with limited life expectance, enhanced probability of haemorrhage (n = 3) and obvious non-compliance (n = 1). Eight patients were offered thrombolytic therapy, but 5 of them denied consent after being comprehensively informed. CONCLUSION: Obviously by far most of patients admitted to internal medicine for DVT are candidates for standard heparin therapy only.     

Does this patient have deep vein thrombosis?

OBJECTIVE: To review the validity of the clinical assessment and diagnostic tests in patients with suspected deep vein thrombosis (DVT). METHODS: A comprehensive review of the literature was conducted by searching MEDLINE from 1966 to April 1997. RESULTS: Individual symptoms and signs alone do not reliably predict which patients have DVT. Overall, the diagnostic properties of the clinical examination are poor; the sensitivity of the clinical examination ranges from 60% to 96%, and the specificity ranges from 20% to 72%. However, using specific combinations of risk factors, symptoms, and physical signs for DVT, clinicians can reliably stratify patients with suspected DVT into low, moderate, or high pretest probability categories of actually suffering from DVT. This stratification process in combination with noninvasive testing, such as compression ultrasonography, simplifies the management strategies for patients with suspected DVT. CONCLUSIONS: Use of a clinical prediction guide that includes specific factors from both the history and physical examination in combination with noninvasive tests simplifies management strategies for patients with suspected DVT.     

Diagnostic imaging in deep vein thrombosis of the limbs

The clinically suspected deep vein thrombosis (DVT) should always be confirmed by instrumental procedures. In fact, about 70% of patients with clinically suspected DVT are shown to be negative on instrumental investigations. Phlebography is still the gold standard in the diagnosis of peripheral DVT. Main phlebographic findings are: persistent filling defect; abrupt interruption of contrast in a vein; lack of opacification in all or some deep veins; flow diversion with opacification of collateral branches. At present, peripheral phlebography is performed when the other noninvasive exams (Color Doppler US and Duplex Doppler) are doubtful, technically limited or when thrombosis of innominate veins or superior vena cava, is suspected. Real-time US enables direct visualization of the limb proximal veins. The venous wall, the venous valves, the thrombus and its development, the anatomic variants, the perivenous structures which may impact on the normal physiology of venous return, are depicted. However, the distal veins of the leg and arm and deep veins (the iliac veins, the superficial femoral vein in the adductor canal) are not accurately visualized. The US findings in DVT include: the presence of echoes within the vascular lumen; the veins in axial scans are not compressible. Pulsed Doppler and duplex Doppler combine the morphologic and functional study. Injury caused by DVT at the valvular level (postphlebitic syndrome) is visualized. Primary deep vein thrombosis caused by valvular disorders (valvular aplasia) is identified. Inadequate superficial and perforating veins to be treated with surgery are mapped. Color Doppler US depicts directly superficial and deep limb veins combining the morphologic with the functional assessment represented by the visualization of the map of flow velocity and direction. Recently, a new diagnostic procedure, the color Doppler Energy (CDE) or Power Doppler has been introduced. Together with mean flow velocity and spectral variance, the signal energy or power is also analyzed. The CDE is independent of the US incidence angle, it does not shows the flow direction, detects particularly slow flows, early canalization of thrombi and non occlusive thrombosis. Color Doppler diagnosis of thrombosis is prompt because an area with absence of color is visualized. Collateral vessels and flow direction within them, is well depicted. Beside the site and extension of thrombosis, color Doppler US is able to directly visualize the distal end of the thrombus, which when floating is at high risk for embolism. CT allows an adequate study of the iliocaval axis and is useful if phlebography or color Doppler US are not diagnostic. Iliocaval thrombosis represents a not infrequent finding during abdominal CT. The thrombus appears as a hypodense mass encircled by the hyperdense rim of contrast medium.     

Clinical utility of prothrombin fragment 1+2, thrombin antithrombin III complexes and D-dimer measurements in the diagnosis of deep vein thrombosis following total hip replacement

BACKGROUND: Measurements of prothrombin fragment 1+2 (F1+2), thrombin antithrombin III complexes (TAT) and D-dimer plasma levels have been proposed as non-invasive screening tests to exclude postoperative deep venous thrombosis (DVT). We investigated the diagnostic efficacy of these coagulation activation markers to rule out postoperative DVT in patients undergoing hip surgery under antithrombotic prophylaxis. METHODS: In this substudy of a randomized double-blind thrombosis prophylaxis trial comparing three doses of desirudin (10, 15 or 20 mg b.i.d.) with unfractionated heparin (5000 IU t.i.d.) we used ELISA procedures to measure F1+2, TAT and D-dimer in 159 patients undergoing total hip replacement at baseline (day 0) and on postoperative days 1, 3 and 6. Bilateral venography was performed in all cases 8-11 days after surgery. RESULTS: For the F1+2 assay sensitivity ranged from 73 to 83% in the three postoperative days investigated, and negative predictive value (NPV) from 68 to 74%. For TAT and D-dimer sensitivity ranged from 71 to 73% and from 71 to 83% and NPV from 61 to 65% and from 61 to 74% respectively. INTERPRETATION: In terms of sensitivity and NPV F1+2 and D-dimer are equivalent and are superior to TAT. However, their accuracy is too low to rule out the presence of DVT after hip surgery under antithrombotic prophylaxis.