The Use Of Non-Invasive Testing And Venography For The Diagnosis Of Acute Recurrent Deep Vein Thrombosis

1981 ◽  
Author(s):  
R Hull ◽  
C Carter ◽  
P Ockelford ◽  
J Hirsh ◽  
A Zielinsky ◽  
...  
Keyword(s):  
Deep Vein Thrombosis ◽  
Anticoagulant Therapy ◽  
Clinical Utility ◽  
Impedance Plethysmography ◽  
First Episode ◽  
Invasive Approach ◽  
Vein Thrombosis ◽  
Non Invasive ◽  
Deep Vein

Impedance plethysmography (IPG) combined with leg scanning is highly sensitive and specific for deep vein thrombosis (DVT) in patients with their first episode of clinically suspected DVT. This approach has not been evaluated in patients with suspected recurrent DVT. In this group of patients venography alone is of limited value in excluding acute DVT in the presence of previous DVT but is useful if constant intraluminal filling defects (ILFD) suggesting acute DVT are present. We have evaluated the clinical utility of IPG plus leg scanning and venography in 132 patients with clinically suspected acute recurrent DVT. If the IPG on referral was negative the patient was leg scanned daily for 72 hours and if both were negative, anticoagulant therapy was witheld. The validity and safety of this approach was tested by 3 months follow-up. If IPG was positive, venography was performed to distinguish ILFD’s from chronic DVT. If ILFD’s were detected, anticoagulant therapy was commenced. If no ILFD’s were detected the patient was leg scanned for 72 hours and if negative treatment was witheld. The clinical utility of this non-invasive approach is demonstrated by the results of this study. Of 132 patients, 82 (62%) were negative by both non-invasive tests and none died, developed pulmonary embolism or recurrent DVT during follow-up. The remaining 50 patients were positive by noninvasive testing; in 31 patients ILFD’s were detected and in 16 venography was indeterminate showing collaterals, absent segments, recanalization or inadequate visualization. The leg scan was positive in 10 of the latter 16 patients. Thus the diagnosis of recurrent acute DVT was established by the presence of ILFD’s or a positive leg scan. In 6 patients with a positive IPG, negative leg scan and indeterminate venogram the diagnosis remained uncertain. In conclusion this combined non-invasive and invasive approach provided definitive management in 126 of 132 patients (95%).

THE ROLE OF Tc-99m RED BLOOD CELL (RBC) VENOGRAPHY IN PATIENTS WITH CLINICALLY SUSPECTED DEEP VEIN THROMBOSIS

1987 ◽  
Author(s):  
J R Leclerc ◽  
T Welfson ◽  
C Rush ◽  
L Lepanto ◽  
A Arzoumanian ◽  
...  
Keyword(s):  
Deep Vein Thrombosis ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Impedance Plethysmography ◽  
First Episode ◽  
Predictive Values ◽  
Vein Thrombosis ◽  
Deep Vein

Although it has been available for a number of years, Tc-99m RBC venography has never been evaluated in an epidemiological study. We have compared Tc-99m RBC venography to impedance plethysmography (IPG) in 113 consecutive eligible patients with clinically suspected first episode of deep vein thrombosis (DVT). IPG was performed at initial presentation (day 0) and RBC venography within the next 72 hours.RBC venography was performed by labelling in vitro 5ml of patients' red blood cell with 20 millicuries of Tc-99m. Patients with an initially abnormal IPG underwent contrast venography to rule out a falsely positive test result. Patients with an initially normal IPG had the test repeated at day 1, 3, 5 to 7 and 10 to 14. Anticoagulant treatment was witheld in all patients who remained normal by serial IPG testing. All patients underwent a 3 month follow-up period. RBC venography was considered abnormal if there was a 50% or greater decrease in isotope concentration in a deep vein compared to the same vein in the other leg. The sensitivity of RBC venography was 79% with 95% confidence limits (C. L.) from 59% to 92%. Specificity was 61% (95% C. L. from 51% to 71%). Positive and negative predictive values were 37% (95% C. L. from 25% to 51%) and 91% (95% C. L. from 81% to 96%) respectively. None of the patients who remained normal by serial IPG testing died from or had objectively documented venous thromboembolism during the follow-up period. We conclude that : 1)RBC venography is non-specific and, 2) a decision to treat should not be made on the basis of the results of this test alone in view of its low positive predictive value.

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

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.

The Diagnosis of Established Deep Vein Thrombosis

1979 ◽  
Author(s):  
R. Hull ◽  
J. Hirsh
Keyword(s):  
Deep Vein Thrombosis ◽  
Doppler Ultrasonography ◽  
Clinical Symptoms ◽  
Reference Method ◽  
Impedance Plethysmography ◽  
Vein Thrombosis ◽  
Non Invasive ◽  
Patient Morbidity ◽  
Low Sensitivity ◽  
Deep Vein

It is now generally accepted that the clinical diagnosis of deep venous thrombosis (DVT) is inaccurate both because of low sensitivity and specificity. Because more than 50% of symptomatic patients fail to show thrombi on venography, anticoagulant therapy on the basis of clinical symptoms of DVT is not acceptable. Venography has been the standard reference method for the diagnosis of DVT but is invasive and consequently associated with patient morbidity. Impedance plethysmography (IPG) and Doppler ultrasonography (Doppler) are both non-invasive and, in patients with clinically suspected DVT, are sensitive and specific tests for proximal DVT. Both tests are relatively insensitive to calf DVT. IPG has the advantage of being an objective technique whereas Doppler is subjective and its accuracy may suffer in inexperienced hands. 125I fibrinogen leg scanning (leg scanning) is an inappropriate test when used alone in patients with clinically suspected DVT as it is insensitive in the upper thigh, may be negative in 30% of patients with established DVT and may take up to 72 hours to become positive. The combination, however, of IPG and leg scanning provides an accurate approach for the detection of both proximal and calf DVT in patients with established DVT. This approach is not associated with patient morbidity and offers the clinician an alternative to venography.

COMPUTERIZED IMPEDANCE PLETHYSMOGRAPHY, A NEW PLETHYSMOGRAPHIC METHOD TO DETECT DEEP VEIN THROMBOSIS

1987 ◽  
Author(s):  
P Prandoni ◽  
M Vigo ◽  
M V Huisman ◽  
J Jonker ◽  
H R Büller ◽  
...  
Keyword(s):  
Deep Vein Thrombosis ◽  
Discriminant Analysis ◽  
Impedance Plethysmography ◽  
Single Test ◽  
Vein Thrombosis ◽  
Non Invasive ◽  
Impedance Plethysmograph ◽  
Deep Vein ◽  
Center Study ◽  
Sensitive Method

Since the clinical diagnosis of deep vein thrombosis (DVT) is unreliable, several invasive and non-invasive methods have been developed recently. Of these, impedance plethysmography (IPG) is a widely employed technique based on measurement of changes in blood volume produced by temporary obstruction. IPG has been shovn in large prospective studies in symptomatic patients to be a safe and effective alternative to contrast venography, if used either in combination with 1251-fibrinogen legscanning or serially as a single test. Currently available impedance plethysmographs are limited by several technical and operational problems. Therefore, a new computerized impedance plethysmograph (CIP) was developed, having the following characteristics: portability, battery operated and fully automated. A prospective two-center study in 299 consecutive outpatients was done to compare the efficacy of CIP vs. venography in patients with symptomatic DVT. Using a blind design i.e. care was taken to insure that CIP and venography were performed and interpreted independently. The results in patients without venography proven thrombosis and those with proximal vein thrombosis were subjected to a discriminant analysis producing a line of best discrimination between normal and proximal vein thrombosis. In 14 patients it was not possible to obtain an adequate CIP tracing. 12 patients were not entered because of refusal to undergo venography and 15 patients were excluded from analysis because of poor opacification of the proximal veins. On the basis of discriminant analysis 138 of the CIP results were classified as normal and 120 as abnormal. 175 patients were normal on venography and 83 had proximal thrombosis. The sensitivity of CIP for proximal vein thrombosis was thus 95% while the speci-+ ficity was 77%. It is concluded that computerized impedance plethysmography is a potentially sensitive method to detect proximal vein thrombosis in patients with clinically suspected deep vein thrombosis.

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