daignosis and investigation of DVT

1. Acute Deep Venous
Thrombosis: Clinical and
Diagnostic Evaluation
by
Mohammed Salah
Ass .lecturer –vas .surgery department

2. Introduction
 DVT is one of the most significant public health
problems.
 Economic impact is very huge .
 Early diagnosis of acute DVT is necessary for
achieving the best outcomes

3. Introduction
 detection of this disease is challenging as its early
stages are frequently subclinical.
 To address this challenge, strategies have been
developed that include risk assessment as the first
diagnostic step.
 Adaptation of these strategy make clinical diagnosis
of acute DVT is more accurate .

4. Cost -effectiveness
 producing optimum results for the expenditure.
 continuous shift toward early treatment of the
majority of the patients based on the clinical
information, reserving more expensive diagnostic
tests for patients who require invasive treatment.

5. CLINICAL
ASSESSMENT

6. Clinical picture
 The clinical manifestations of acute DVT varies
greatly.
 About 50% of cases may be asymptomatic.
 Broad variation is a result of multiple pathologic
processes

7.  Such pathological processes include
1.Timing of presentation …… severity
2.Anatomic distribution……degree of occlusion
3.Functional state of lymphatic system
4. preexisting venous and lymphatic insufficiency
 all these factors lead to varieties in C/P from mild edema
to phlegmasia cerulae or venous gangrene.

8. Signs and symptoms
Common symptoms of DVT include:
 Leg pain and tenderness
 Oedema (swelling)
 Redness

9. C/P
 The most common symptoms and signs of DVT are dull
ache or pain in the leg, tenderness, swelling, erythema,
cyanosis, and fever.
 Edema, cyanosis, and pain are features of phlegmasia
cerulea
 Venous gangrene is a rare condition that occurs usually
in patients with cancer, can occur with heparin-induced
thrombocytopenia with thrombosis, and is generally
associated with warfarin-mediated protein C depletion

10. Phlegmasia cerulea dolens
Venous gangrene

11. C/P
 The most common symptom of calf pain variable
sensitivity and specificity due to high prevalence of
the same signs and symptoms in patients without
DVT.
 Withholding treatment on the basis of clinical
evaluation in primary care settings leads to
inadequate management of more than 10% of
patients with DVT.
 High variability and lack of specificity limit the role of
clinical examination in patients with suspected DVT

12. Signs and Symptoms of
DVT’s
Recognize and report
signs/symptoms of a DVT
including:
 Unilateral edema
 Erythema
 Calf tenderness
 Pale leg & cool with diminished
arterial pulse

13.  Pratt's test: Squeezing of posterior calf elicits pain.
 Homan’s sign (discomfort in the calf muscles on
forced foot dorsiflexion w/ knee straight; NOTE:
Homan’s sign is neither sensitive nor specific;
Present in <1/3 of patients with confirmed DVT;
Found in >50% of patients without DVT) (Schreiber,
2009)

14. DIAGNOSTIC
TESTS

15. D-dimers: what is the role?
 D-dimer is a product of fibrin proteolysis by
plasmin; therefore, its elevated levels signify
that fibrinolysis of complexed fibrin is taking
place
 In other words D-dimer: degradation product
of cross-linked fibrin
 The appeal: a simple blood test .

16. D-dimers
 The concentration of D-dimer in plasma has become
a widely used marker for the diagnosis of DVT its
elevated levels signify that fibrinolysis of complexed
fibrin is taking place.
 High sensitivity, low specificity
• Quantitative D-dimer < 500 ng/ml makes PE less
likely.

17. D-dimers
 Elevated d-dimer common w/o clot - especially as
part of the response to injury
1.Pathological as surgery patient , Trauma
Cancer patient ,patient with thrombotic disorders
2.Physiological as pregnancy

18. D-dimers
 The degree of D-dimer elevation in patients with
DVT varies with the size and extent of the thrombus,
the time from its onset, and the use of
anticoagulation.
 Different types for assay most accurate one for DVT
is ELISA but most laborious and slow. Rapid point
of- care assays are probably the most practical as
the results are obtainable within minutes and their
sensitivity is comparable to that of the enzyme-
linked immunosorbent assay

19. D-dimers
 concentration of D-dimer below the cutoff value
indicates a very low probability of DVT, it does not
exclude it with sufficient accuracy, especially in
cases of distal thrombi, use of anticoagulation, or
long duration between the onset of thrombosis and
testing
 Similar to clinical evaluation, the use of D-dimer as a
single diagnostic tool may result in inadequate
management of more than 15% of patients with
suspected DVT.

20. Duplex ultrasonography
 Duplex ultrasonography remains the dominant
diagnostic test of choice for the detection of DVT.
 accuracy, lack of radiation, portability,
noninvasiveness, and relative cost-effectiveness. In
addition, ultrasound has the ability to distinguish
among nonvascular pathologic processes, such as
inguinal adenopathy, Baker’s cyst, abscess, and
hematoma

21. Pitfalls of Duplex
 Misidentification of veins
 missing of duplicate venous systems;
 systemic illness or hypovolemia resulting in decreased venous
distention
 suboptimal imaging in obese or edematous patients; and
areas not amenable to compression, such as the iliac veins,
the femoral vein at the adductor canal, and the subclavian
veins.
 As with most ultrasound-based imaging studies, the quality of
the examination depends on the skill of the technologist
performing the study.

22. diagnostic criteria for DVT
in Duplex
 Duplex ultrasound diagnostic criteria for DVT
 1.increased intraluminal echogenicity,
 2. increased venous diameter,
 3.inability of the vein to collapse under a moderate
pressure from the transducer,
 4.absence of spontaneous blood flow,
 5. and absence of flow augmentation with distal
compression

23. Color duplex scan of DVT

24. diagnostic criteria for DVT
in Duplex
 Among these factors, inability to compress the vein
is the most widely used objective criterion for the
diagnosis of DVT.
 limitation of compression ultrasound is its lack of
accuracy in the evaluation of calf veins
 evaluation of venous flow with color Doppler and
spectral Doppler can improve the accuracy of
compression ultrasonography

26. Plethysmography
 Plethysmography is a noninvasive method of
estimating changes in volume in an extremity.
 Because all other tissues maintain constant volume
during the short period of testing, any recorded
volumetric differences reflect changes in blood
volume.

27. Plethysmography
 Several plethysmographic techniques with different
sensors have been used to measure changes in blood
volume
 strain-gauge plethysmography (SGP) primarily been
used in the past for the diagnosis of deep venous
thrombosis(DVT),
 impedance plethysmography (IPG),
 Photoplethysmography (PPG),
 and air plethysmography (APG).

28. Plethysmography
 assess thrombus resolution and recanalization.
 Because the occlusive cuff is placed on the thigh,
plethysmographic diagnosis of calf DVT is especially
problematic.

29. Limitation of Plethysmography
 Successful recordings from SGP require full cooperation
from the patient.
 It cannot be performed on patients;
 who are unable to lie flat. Prolonged recumbency, muscle
wasting, and cardiac failure may result in measurement
errors.
 Patients with limb injuries, bandages, casts, or severe
edema
are unsuitable candidates for SPG

30. CT VENOGRAPHY
 Computed tomographic arteriography is an excellent
technique for the diagnosis of pulmonary embolism.
 (CTV), has yet to gain traction for the diagnosis of
acute DVT in the lower or upper extremities.
 The diagnostic capabilities of CTV are remarkable in
the thigh and pelvis compared with duplex
ultrasound

31. CT VENOGRAPHY
 In addition, when CTV is used in conjunction for
evaluation of PE, it adds only 3 to 5 minutes to the
examination, making it an attractive option as the
sole diagnostic modality for acute lower extremity
DVT
 CTV has not been well studied for acute calf vein
 less cost-effective than duplex ultrasound.
 involves the use of contrast material, and it uses
radiation

32. Imaging
MRV

33. Advantages of MRV
 MRV is less expensive than contrast venography but
more expensive and less operator dependent than
duplex ultrasound.
 Non–contrast-enhanced techniques include time-of-
flight imaging.
 Contrast enhanced MRV. such gadolinium.

34. MRV
 MRV used to diagnose acute DVT in larger venous
segments, but less sensitivities when smaller
diameter veins are evaluated.
 vessel wall enhancement can be visualized with
acute thrombus, allowing the examiner a crude
detection of thrombus age

35. Disadvantages of MRV
 demands a nonmoving patient and long imaging
times that, when paired, can be a significant hurdle.
 The below-knee segments of venous anatomy are
often paired, accounting for significant artifact during
post processing of the images
 gadolinium can be toxic in patients with renal
dysfunction

36. Conclusion
MRV
 MRV can be preserved for detection of thrombus in
centrally located venous structures not always
accessible to duplex ultrasonography.
 MRV useful for detection of hypogastric venous
thrombosis
 a remarkable 27% of patients without a detectable
source of thrombus by duplex ultrasound who have
sustained a PE had thrombus identified by MRV.

37. Contrast venography
 Contrast venography for the sole purpose of diagnosing DVT is
largely of historical interest.
 It is expensive and inconvenient compared with other
diagnostic modalities and potentially causes patient discomfort.
 Complications of the examination include nephrotoxicity,allergy,
phlebitis, and the need for intravenous access.
 Nevertheless, contrast venography can be useful when other
studies have not produced a solid diagnosis, making it
important to retain this technology for diagnosis and
therapeutics.

38. Contrast venography
 The Rabinov-Paulin technique uses spot film, and
the long-leg technique uses cine film.
 contrast venography should be used as the “golden
backup” when the diagnosis of acute DVT remains
in question after a venous duplex examination

39. Venogram
shows DVT

40. 18F-FDG
 18F-labeled fluorodeoxyglucose positron emission
tomography/computed tomography (18F-FDG
PET/CT) .18F-FDG is a glucose analogue that is
actively and avidly absorbed by tissues and cells
with rapid metabolism. Among these are tumor cells,
endothelial cells, macrophages, and lymphocytes

41. 18F-FDG PET/CT
 18F-labeled fluorodeoxyglucose positron emission
tomography/computed tomography (18F-FDG
PET/CT) has been shown to:
 detect acute DVT, to determine thrombus age.
 differentiate acute thrombus from tumor thrombus.

42. DIAGNOSTIC STRATEGIES
DIAGNOSTIC STRATEGIES

43. DIAGNOSTIC STRATEGIES
 In the absence of a single reliable, accurate, and
inexpensive diagnostic test, stratification of patients
based on their risk of DVT substantially enhances clinical
decision making.
 strategies have been developed that include risk
assessment as the first diagnostic step.
 The result is a continuous shift toward early treatment of
the majority of the patients based on the clinical
information, reserving more expensive diagnostic tests
for patients who require invasive treatment.

44. Two-level DVT Wells score
Clinical feature Points
Active cancer (treatment ongoing, within 6 months, or palliative) 1
Paralysis, paresis or recent plaster immobilisation of the lower
extremities
1
Recently bedridden for 3 days or more or major surgery within
12 weeks requiring general or regional anaesthesia
1
Localised tenderness along the distribution of the deep
venous system
1
Entire leg swollen 1
Calf swelling at least 3 cm larger than asymptomatic side 1
Pitting oedema confined to the symptomatic leg 1
Collateral superficial veins (non-varicose) 1
Previously documented DVT 1
An alternative diagnosis is at least as likely as DVT −2
Clinical probability simplified score
DVT likely 2 points or more
DVT unlikely 1 point or less
a Adapted with permission from Wells PS et al. (2003) Evaluation of D-dimer in the diagnosis of suspected deep-vein
thrombosis. New England Journal of Medicine 349: 1227–35

45. DIAGNOSTIC STRATEGIES
 It is increasingly recognized that the optimal
approach to DVT diagnosis includes risk
stratification based on the Wells score and D-dimer
assay, followed by diagnostic testing in high-risk
patients and in patients who require advanced
treatment modalities.
 In low and intermediate risk patients, the
combination of a Wells score and negative D-dimer
result reaches a negative predictive value
approaching 100%.

47. DIAGNOSTIC STRATEGIES
 Evaluation of patients with a high probability of DVT
is more problematic. Negative D-dimer results in
these patients are associated with PE rates of up to
15%.
 So, treatment should be started before additional
testing is completed. When anticoagulation is
initiated, delay in definitive diagnostic studies has
been shown to be safe.

49. DVT during pregnancy
 The risk of bleeding complications limits the use of
anticoagulation to cases with confirmed DVT.
 D-dimer levels have been known to increase during
the course of a normal pregnancy and are of
unproven utility during pregnancy.
 For these reasons, ultrasound remains the preferred
diagnostic test for detection of DVT in pregnancy.

50. Thrombophilia screening
Factor V leiden, Prot C/S deficiency
Antithrombin III deficiency
• Idiopathic DVT < 50 years
• Family history of DVT
• Thrombosis in an unusual site
• Recurrent DVT

51. Patient with suspect symptomatic
Acute lower extremity DVT
Venous duplex scan negative Low clinical probability observe
High clinical probability
Repeat scan /
Venography
negativepositive
Evaluate coagulogram /thrombophilia/ malignancy
Anticoagulant therapy
contraindication
yes IVC filter
No
pregnancy LMWH
OPD LMWH
hospitalisation UFH
+ warfarin
Compression treatment