Features of Thrombi and Diagnostic Accuracy of Impedance Plethysmography in Symptomatic and Asymptomatic Deep Vein Thrombosis

SummaryImpedance plethysmography (IPG) has high sensitivity and specificity in patients with symptomatic deep vein thrombosis (DVT) while it fails to detect asymptomatic DVT. The aim of this study was to determine whether the features of thrombi such as location, size and occlusiveness could explain the different accuracy of IPG in symptomatic and asymptomatic DVT patients. One-hundred and seventeen consecutive outpatients with a clinical suspicion of DVT and 246 consecutive patients undergoing hip surgery were admitted to the study. In symptomatic patients IPG was performed on the day of referral, followed by venography, while in asymptomatic patients IPG was performed as a surveillance programme, followed by bilateral venography.A venography proved DVT was observed in 37% of the symptomatic patients and 34% of the asymptomatic limbs. A significantly higher proportion of proximal DVTs was found in symptomatic patients than in asymptomatic patients (78% vs 46%; p = 0.001). The mean Marder score, taken as an index of thrombus size, was significantly higher in symptomatic patients than in asymptomatic patients (19.0 vs 9.6; p = 0.0001). A significantly higher proportion of occlusive DVTs was observed in symptomatic than in asymptomatic patients (69% vs 36%; p = 0.001).We conclude that the unsatisfactory diagnostic accuracy of IPG in asymptomatic DVT is due to the high prevalence of distal, small and non occlusive thrombi. Such thrombi are unlikely to cause a critical obstruction of the venous outflow and therefore to produce a positive IPG.

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Diagnosis Of Deep Vein Thrombosis - “The Case for NonInvasive Testing”

10.1055/s-0038-1652735 ◽

1981 ◽

Author(s):

R Hull ◽

J Hirsh

Keyword(s):

Deep Vein Thrombosis ◽

High Sensitivity ◽

Cost Effective ◽

Impedance Plethysmography ◽

Noninvasive Testing ◽

Vein Thrombosis ◽

Non Invasive ◽

Long Term Follow Up ◽

Deep Vein ◽

High Degree

Ascending venography, although the diagnostic standard for deep vein thrombosis (DVT), has important clinical pitfalls and shortcomings. It is invasive and thus not readily repeated: its use is associated with significant discomfort in many patients and in 3-4% of patients post-veno- graphic phlebitis is induced. A high degree of technical and interpretive skill is required and in up to 20% of patients routine ascending venography fails to visualize the external and common iliac veins. In many hospitals, outpatient access is not readily available necessitating admission to hospital for elective venography. Non-invasive testing with impedance plethysmography (IPG) is gaining increasing acceptance and use because it is objective, versatile and free of morbidity. IPG is sensitive and specific for symptomatic proximal DVT, but has the potential limitation that it is insensitive to calf DVT. Because of this, two different non-invasive approaches are currently advocated: a) serial IPG’s to detect calf vein thrombi which extend proximally (advocates of this approach suggest that calf DVT rarely lead to symptomatic pulmonary emboli unless proximal extension occurs) and b) addition of leg scanning to detect calf DVT. The effectiveness of serial IPG’s is uncertain and to resolve this issue we are currently performing a randomized trial. Multiple large studies however demonstrate that because of both high sensitivity and specificity, the combined approach of IPG and leg scanning provides a replacement for venography in the majority of symptomatic patients. Furthermore, the safety of witholding anticoagulant therapy in patients negative by combined IPG and leg scanning has been confirmed by long-term follow-up. Combined IPG and leg scanning is more cost-effective than elective venography because these non-invasive tests are readily performed in the emergency room or clinic, thus preventing unnecessary admission to hospital of patients with clinically suspected DVT who are negative by testing.

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Diagnostic Accuracy of Computerized Impedance Plethysmography in the Diagnosis of Symptomatic Deep Vein Thrombosis: A Controlled Venographic Study

Angiology ◽

10.1177/000331979004100709 ◽

1990 ◽

Vol 41 (7) ◽

pp. 559-564 ◽

Cited By ~ 7

Author(s):

Giancarlo Agnelli ◽

Mauro Longetti ◽

Benilde Cosmi ◽

Luciano Lupattelli ◽

Francesco Barzi ◽

...

Keyword(s):

Deep Vein Thrombosis ◽

Diagnostic Accuracy ◽

Impedance Plethysmography ◽

Symptomatic Deep Vein Thrombosis ◽

Vein Thrombosis ◽

Deep Vein

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Confirmation of the Failure of Computerized Impedance Plethysmography in the Diagnostic Management of Patients with Clinically Suspected Deep-Vein Thrombosis

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646500 ◽

1991 ◽

Vol 66 (06) ◽

pp. 744-744

Author(s):

Anthonie W A Lensing ◽

Harry R Büller ◽

Jan Wouter ten Cate ◽

Paolo Prandoni

Keyword(s):

Deep Vein Thrombosis ◽

Impedance Plethysmography ◽

Vein Thrombosis ◽

Diagnostic Management ◽

Deep Vein

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D-Dimers, Thrombin Antithrombin III Complexes and Prothrombin Fragments 1 + 2: Diagnostic value in Clinically Suspected Deep Vein Thrombosis

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647449 ◽

1991 ◽

Vol 65 (01) ◽

pp. 028-032 ◽

Cited By ~ 105

Author(s):

B Boneu ◽

G Bes ◽

H Pelzer ◽

P Sié ◽

H Boccalon

Keyword(s):

Deep Vein Thrombosis ◽

Antithrombin Iii ◽

High Sensitivity ◽

Diagnostic Value ◽

Predictive Values ◽

Vein Thrombosis ◽

High Negative Predictive Value ◽

Deep Vein ◽

D Dimer ◽

Mercury Strain Gauge

SummaryThis study was performed to determine the accuracy of D-Dimer fibrin derivatives, thrombin-antithrombin III (TAT) complexes and prothrombin fragments 1 + 2 (F 1 + 2) determinations for the diagnosis of deep vein thrombosis (DVT). One hundred and sixteen consecutive patients referred to the angiology unit of our hospital for a clinically suspected DVT were investigated. They were submitted to mercury strain gauge plethysmography and to ultrasonic duplex scanning examination; in cases of inconclusive results or of proximal DVT (n = 35), an ascending phlebography was performed. After these investigations were completed, the diagnosis of DVT was confirmed in 34 and excluded in 82. One half of the patients were already under anticoagulant therapy at the time of investigation. The 3 biological markers were assayed using commercially available ELISA techniques and the D-Dimer was also assayed with a fast latex method. The normal distribution of these markers was established in 40 healthy blood donors. The most accurate assay for the diagnosis of DVT was the D-Dimer ELISA which had both a high sensitivity (94%) and a high negative predictive value (95%). The D-Dirner latex, TAT complexes and F 1 + 2 were far less sensitive and provided negative predictive values which ranged between 78 and 85%. In spite of positive and significant correlations between the levels of ihe 3 markers, their association did not improve their overall accuracy for detecting D\/L Therefore, with the exception of the D-Dimer ELISA, these markers were of little value for the diagnosis of DVT in this specific population.

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Is Colour Doppler Ultrasound a Sensitive Screening Method in Diagnosing Deep Vein Thrombosis after Hip Surgery ?

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650252 ◽

1996 ◽

Vol 75 (02) ◽

pp. 242-245 ◽

Cited By ~ 20

Author(s):

Marie Magnusson ◽

Bengt I Eriksson ◽

Peter Kãlebo ◽

Ramon Sivertsson

Keyword(s):

Deep Vein Thrombosis ◽

High Risk ◽

Doppler Ultrasound ◽

Predictive Value ◽

Screening Method ◽

Colour Doppler ◽

Vein Thrombosis ◽

Colour Doppler Ultrasound ◽

Asymptomatic Patients ◽

Deep Vein

SummaryPatients undergoing orthopedic surgery are at high risk of developing deep vein thrombosis. One hundred and thirty-eight consecutive patients undergoing total hip replacement or hip fracture surgery were included in this study. They were surveilled with colour Doppler ultrasound (CDU) and bilateral ascending contrast phlebography. The prevalence of proximal and distal DVT in this study was 5.8% and 20.3% respectively.CDU has a satisfactory sensitivity in patients with symptomatic deep vein thrombosis, especially in the proximal region. These results could not be confirmed in the present study of asymptomatic patients. The sensitivity was 62.5% (95% confidence interval: C.I. 24-91%) and the specificity 99.6% (C.I. 98-100%) for proximal DVT; 53.6% (C.I. 34-73%) and 98% (C.I. 96-99%) respectively for distal thrombi. The overall sensitivity was 58.1% (C.I. 39-75%) and the specificity 98% (C.I. 96-99%). The positive predictive value was 83.3% (C.I. 36-99%) and 75% (C.I. 51-91%) for proximal and distal DVT respectively. The negative predictive value was 98.9% (C.I. 98-100%) and 94.9% (C.I. 92-98%) for proximal and distal DVT respectively. The results of this study showed that even with a highly specialised and experienced investigator the sensitivity of CDU was too low to make it suitable for screening purposes in a high risk surgical population.

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