Deep Vein Thrombosis Guide

DEEP VENOUSDEEP VENOUS
THROMBOSISTHROMBOSIS
DR.FAZAL HUSSAIN KHALILDR.FAZAL HUSSAIN KHALIL

DefinitionDefinition
 Deep vein thrombosis is theDeep vein thrombosis is the
formation of a blood clot in one offormation of a blood clot in one of
the deep veins of the body, usuallythe deep veins of the body, usually
in the legin the leg

ETIOLOGYETIOLOGY
 DVT ususally originates in the lower extremityDVT ususally originates in the lower extremity
venous level ,starting at the calf vein level andvenous level ,starting at the calf vein level and
progressing proximally to involve poplitealprogressing proximally to involve popliteal
,femoral ,or iliac system. .80 -90 % pulmonary,femoral ,or iliac system. .80 -90 % pulmonary
emboli originates here .emboli originates here .

Virchow triedVirchow tried
 More than 100 years ago, Virchow described aMore than 100 years ago, Virchow described a
triad of factors oftriad of factors of
 venous stasis,venous stasis,
 endothelial damage, andendothelial damage, and
 hypercoagulable statehypercoagulable state

Venous stasisVenous stasis
 prolonged bed rest (4 days or more)prolonged bed rest (4 days or more)
 A cast on the legA cast on the leg
 Limb paralysis from stroke or spinal cord injuryLimb paralysis from stroke or spinal cord injury
 extended travel in a vehicleextended travel in a vehicle

HypercoagulabilityHypercoagulability
 Surgery and trauma responsible for up to 40% of allSurgery and trauma responsible for up to 40% of all
thromboembolic diseasethromboembolic disease
 MalignancyMalignancy
 Increased estrogen (due to a fall in protein ‘S) IncreasedIncreased estrogen (due to a fall in protein ‘S) Increased
estrogen occurs duringestrogen occurs during
 all stages of pregnancy—all stages of pregnancy—
 the first three months postpartum,the first three months postpartum,
 after elective abortion, andafter elective abortion, and
 during treatment with oral contraceptive pillsduring treatment with oral contraceptive pills

Inherited disorders of coagulationInherited disorders of coagulation
 deficiencies of protein ‘S,deficiencies of protein ‘S,
 ’’ protein ‘C,’ andprotein ‘C,’ and
 antithrombin III.antithrombin III.

Acquired disorders of coagulationAcquired disorders of coagulation
 nephrotic syndrome results in urinary loss ofnephrotic syndrome results in urinary loss of
antithrombin III, this diagnosis should beantithrombin III, this diagnosis should be
considered in children presenting withconsidered in children presenting with
thromboembolic diseasethromboembolic disease
 Antiphospholipid antibodies accelerateAntiphospholipid antibodies accelerate
coagulation and include the lupus anticoagulantcoagulation and include the lupus anticoagulant
and anticardiolipin antibodies.and anticardiolipin antibodies.

Inflammatory processes, such asInflammatory processes, such as
• systemic lupus erythematosus (SLE),systemic lupus erythematosus (SLE),
• sickle cell disease, andsickle cell disease, and
•inflammatory bowel disease (IBD),inflammatory bowel disease (IBD),
also predispose to thrombosis, presumably due toalso predispose to thrombosis, presumably due to
hypercoagulabilityhypercoagulability

Endothelial InjuryEndothelial Injury
 Trauma,Trauma,
 surgery, andsurgery, and
 invasive procedure may disrupt venous integrityinvasive procedure may disrupt venous integrity
 Iatrogenic causes of venous thrombosis areIatrogenic causes of venous thrombosis are
increasing due to the widespread use of centralincreasing due to the widespread use of central
venous catheters, particularly subclavian andvenous catheters, particularly subclavian and
internal jugular lines. These lines are aninternal jugular lines. These lines are an
important cause of upper extremity DVT,important cause of upper extremity DVT,
particularly in children.particularly in children.

Clinical PathophysiologyClinical Pathophysiology
 The nidus for a clot is often an intimal defectThe nidus for a clot is often an intimal defect
 When a clot forms on an intimal defect, theWhen a clot forms on an intimal defect, the
coagulation cascade promotes clot growthcoagulation cascade promotes clot growth
proximally. Thrombus can extend from theproximally. Thrombus can extend from the
superficial veins into the deep system fromsuperficial veins into the deep system from
which it can embolize to the lungs.which it can embolize to the lungs.

 Opposing the coagulation cascade is theOpposing the coagulation cascade is the
endogenous fibrinolytic system. After the clotendogenous fibrinolytic system. After the clot
organizes or dissolves, most veins will recanalizeorganizes or dissolves, most veins will recanalize
in several weeks. Residual clots retract asin several weeks. Residual clots retract as
fibroblasts and capillary development lead tofibroblasts and capillary development lead to
intimal thickening.intimal thickening.
 Venous hypertension and residual clot mayVenous hypertension and residual clot may
destroy valves, leading to the postphlebiticdestroy valves, leading to the postphlebitic
syndrome, which develops within 5-10 yearssyndrome, which develops within 5-10 years

 Edema, sclerosis, and ulceration characterize thisEdema, sclerosis, and ulceration characterize this
syndrome, which develops in 40-80% of patients withsyndrome, which develops in 40-80% of patients with
DVT.DVT.
 patients also can suffer exacerbations of swelling andpatients also can suffer exacerbations of swelling and
pain, probably as a result of venous dilatation andpain, probably as a result of venous dilatation and
hypertensionhypertension
 Pulmonary embolism (PE) is a serious complicationPulmonary embolism (PE) is a serious complication
of DVT. Many episodes of pulmonary embolism goof DVT. Many episodes of pulmonary embolism go
unrecognized, and at least 40% of patients with DVTunrecognized, and at least 40% of patients with DVT
have clinically silent PE on VQ scanninghave clinically silent PE on VQ scanning

Presentation and PhysicalPresentation and Physical
ExaminationExamination
 Calf pain or tenderness, or bothCalf pain or tenderness, or both
 Swelling with pitting oedemaSwelling with pitting oedema
 Swelling below knee in distal deep veinSwelling below knee in distal deep vein
thrombosis and up to groin in proximal deepthrombosis and up to groin in proximal deep
vein thrombosisvein thrombosis
 Increased skin temperatureIncreased skin temperature
 Superficial venous dilatationSuperficial venous dilatation
 Cyanosis can occur with severe obstructionCyanosis can occur with severe obstruction

 Palpate distal pulses and evaluate capillary refillPalpate distal pulses and evaluate capillary refill
to assess limb perfusion.to assess limb perfusion.
 Move and palpate all joints to detect acuteMove and palpate all joints to detect acute
arthritis or other joint pathology.arthritis or other joint pathology.
 Neurologic evaluation may detect nerve rootNeurologic evaluation may detect nerve root
irritation; sensory, motor, and reflex deficitsirritation; sensory, motor, and reflex deficits
should be notedshould be noted
 Homans'’ sign: pain in the posterior calf or kneeHomans'’ sign: pain in the posterior calf or knee
with forced dorsiflexion of the footwith forced dorsiflexion of the foot

 Search for stigmata of PE such as tachycardiaSearch for stigmata of PE such as tachycardia
(common), tachypnea or chest findings (rare),(common), tachypnea or chest findings (rare),
andand
 exam for signs suggestive of underlyingexam for signs suggestive of underlying
predisposing factors.predisposing factors.

Wells Clinical Prediction GuideWells Clinical Prediction Guide
 The Wells clinical prediction guide incorporates riskThe Wells clinical prediction guide incorporates risk
factors, clinical signs, and the presence or absence offactors, clinical signs, and the presence or absence of
alternative diagnosesalternative diagnoses
 .. Wells Clinical Prediction Guide for DVTClinicalWells Clinical Prediction Guide for DVTClinical
ParameterScoreParameterScore
 Active cancer (treatment ongoing, or within 6 monthsActive cancer (treatment ongoing, or within 6 months
or palliative)1or palliative)1
 Paralysis or recent plaster immobilization 1Paralysis or recent plaster immobilization 1
 Recently bedridden for >3 days or major surgery <4Recently bedridden for >3 days or major surgery <4
weeks1weeks1

 Localized tenderness along the distribution of the deepLocalized tenderness along the distribution of the deep
venous system1venous system1
 Entire leg swelling1Entire leg swelling1
 Calf swelling >3 cm compared to the asymptomatic legCalf swelling >3 cm compared to the asymptomatic leg
11
 Pitting edema (greater in the symptomatic leg)1Pitting edema (greater in the symptomatic leg)1
 Collateral superficial veins (nonvaricose)1Collateral superficial veins (nonvaricose)1
 Alternative diagnosis (as likely or > that of DVT)Alternative diagnosis (as likely or > that of DVT)

 Total of Above ScoreTotal of Above Score
High probability: Score ³3High probability: Score ³3
Moderate probability: Score = 1 or 2Moderate probability: Score = 1 or 2
Low probability: Score £0Low probability: Score £0
 Adapted from Anand SS, et al.Adapted from Anand SS, et al. JAMAJAMA. 1998;. 1998;
279 [14];1094279 [14];1094

Diagnostic StudiesDiagnostic Studies
 Clinical examination alone is able to confirm only 20-Clinical examination alone is able to confirm only 20-
30% of cases of DVT30% of cases of DVT
 Blood TestsBlood Tests
 the D-dimerthe D-dimer
 INR.INR.
 Current D-dimer assays have predictive value for DVT,Current D-dimer assays have predictive value for DVT,
and theand the
 INR is useful for guiding the management of patientsINR is useful for guiding the management of patients
with known DVT who are on warfarin (Coumadin)with known DVT who are on warfarin (Coumadin)

D-dimerD-dimer
 D-dimer is a specific degradation product ofD-dimer is a specific degradation product of
cross-linked fibrin. Because concurrentcross-linked fibrin. Because concurrent
production and breakdown of clot characterizeproduction and breakdown of clot characterize
thrombosis, patients with thromboembolicthrombosis, patients with thromboembolic
disease have elevated levels of D-dimerdisease have elevated levels of D-dimer
 three major approaches for measuring D-dimerthree major approaches for measuring D-dimer
 ELISAELISA
 latex agglutinationlatex agglutination
 blood agglutination test (SimpliREDblood agglutination test (SimpliRED

 False-positive D-dimers occur in patients withFalse-positive D-dimers occur in patients with
 recent (within 10 days) surgery or trauma,recent (within 10 days) surgery or trauma,
 recent myocardial infarction or stroke,recent myocardial infarction or stroke,
 acute infection,acute infection,
 disseminated intravascular coagulation,disseminated intravascular coagulation,
 pregnancy or recent delivery,pregnancy or recent delivery,
 active collagen vascular disease, or metastaticactive collagen vascular disease, or metastatic
cancercancer

Imaging StudiesImaging Studies
 InvasiveInvasive
 venography,venography,
 radiolabeled fibrinogen and.radiolabeled fibrinogen and.
 noninvasivenoninvasive
 ultrasound,ultrasound,
 plethysmography,plethysmography,
 MRI techniquesMRI techniques

venographyvenography
 gold standard” modality for the diagnosis ofgold standard” modality for the diagnosis of
DVTDVT
 AdvantagesAdvantages
 Venography is also useful if the patient has aVenography is also useful if the patient has a
high clinical probability of thrombosis and ahigh clinical probability of thrombosis and a
negative ultrasound,negative ultrasound,
 it is also valuable in symptomatic patients with ait is also valuable in symptomatic patients with a
history of prior thrombosis in whom thehistory of prior thrombosis in whom the
ultrasound is non-diagnostic.ultrasound is non-diagnostic.

side effectsside effects
 phlebitisphlebitis
 anaphylaxisanaphylaxis

Nuclear Medicine StudiesNuclear Medicine Studies
 Because the radioactive isotope incorporatesBecause the radioactive isotope incorporates
into a growing thrombus, this test caninto a growing thrombus, this test can
distinguish new clot fromdistinguish new clot from an old clotan old clot

PlethysmographyPlethysmography
 Plethysmography measures change in lowerPlethysmography measures change in lower
extremity volume in response to certain stimuli.extremity volume in response to certain stimuli.

UltrasonographyUltrasonography
 color-flow Duplex scanning is the imaging testcolor-flow Duplex scanning is the imaging test
of choice for patients with suspected DVTof choice for patients with suspected DVT
 inexpensive,inexpensive,
 noninvasive,noninvasive,
 widely availablewidely available
 Ultrasound can also distinguish other causes ofUltrasound can also distinguish other causes of
leg swelling, such as tumor, popliteal cyst,leg swelling, such as tumor, popliteal cyst,
abscess, aneurysm, or hematoma. abscess, aneurysm, or hematoma.

clinical limitationsclinical limitations
 expensiveexpensive
 reader dependentreader dependent
 Duplex scans are less likely to detect non-Duplex scans are less likely to detect non-
occluding thrombi.occluding thrombi.
 During the second half of pregnancy, ultrasoundDuring the second half of pregnancy, ultrasound
becomes less specific, because the gravid uterusbecomes less specific, because the gravid uterus
compresses the inferior vena cava, therebycompresses the inferior vena cava, thereby
changing Doppler flow in the lower extremitieschanging Doppler flow in the lower extremities

Magnetic Resonance ImagingMagnetic Resonance Imaging
 It detects leg, pelvis, and pulmonary thrombiIt detects leg, pelvis, and pulmonary thrombi
and is 97% sensitive and 95% specific for DVT.and is 97% sensitive and 95% specific for DVT.
 It distinguishes a mature from an immature clot.It distinguishes a mature from an immature clot.
 MRI is safe in all stages of pregnancy.MRI is safe in all stages of pregnancy.

DIFFERENTIAL DIAGNOSISDIFFERENTIAL DIAGNOSIS
o CellulitisCellulitis
ThrombophlebitisThrombophlebitis
o ArthritisArthritis
Asymmetric peripheral edema secondary to CHF, liverAsymmetric peripheral edema secondary to CHF, liver
disease, renal failure, or nephrotic syndromedisease, renal failure, or nephrotic syndrome
lymphangitislymphangitis
Extrinsic compression of iliac vein secondary to tumor,Extrinsic compression of iliac vein secondary to tumor,
hematoma, or abscesshematoma, or abscess
HematomaHematoma
LymphedemaLymphedema

 Muscle or soft tissue injuryMuscle or soft tissue injury
Neurogenic painNeurogenic pain
Postphlebitic syndromePostphlebitic syndrome
Prolonged immobilization or limb paralysisProlonged immobilization or limb paralysis
Ruptured Baker cystRuptured Baker cyst
Stress fractures or other bony lesionsStress fractures or other bony lesions
Superficial thrombophlebitisSuperficial thrombophlebitis
Varicose veinsVaricose veins

ManagementManagement
 Using the pretest probability score calculatedUsing the pretest probability score calculated
from the Wells Clinical Prediction rule, patientsfrom the Wells Clinical Prediction rule, patients
are stratified into 3 risk groups—high, moderate,are stratified into 3 risk groups—high, moderate,
or low.or low.
 The results from duplex ultrasound areThe results from duplex ultrasound are
incorporated as follows:incorporated as follows:
 If the patient is high or moderate risk and theIf the patient is high or moderate risk and the
duplex ultrasound study is positive, treat forduplex ultrasound study is positive, treat for
DVT.DVT.

 If the duplex study is negative and the patient isIf the duplex study is negative and the patient is
low risk, DVT has been ruled out.low risk, DVT has been ruled out.
• When discordance exists between the pretestWhen discordance exists between the pretest
probability and the duplex study result, furtherprobability and the duplex study result, further
evaluation is required.evaluation is required.
 If the patient is high risk but the ultrasoundIf the patient is high risk but the ultrasound
study was negative, the patient still has astudy was negative, the patient still has a
significant probability of DVTsignificant probability of DVT

 a venogram to rule out a calf vein DVTa venogram to rule out a calf vein DVT
 surveillance with repeat clinical evaluation andsurveillance with repeat clinical evaluation and
ultrasound in 1 week.ultrasound in 1 week.
 results of a D-dimer assay to guide managementresults of a D-dimer assay to guide management
 If the patient is low risk but the ultrasoundIf the patient is low risk but the ultrasound
study is positive, some authors recommend astudy is positive, some authors recommend a
second confirmatory study such as a venogramsecond confirmatory study such as a venogram
before treating for DVTbefore treating for DVT

EMERGENCY DEPARTMANTEMERGENCY DEPARTMANT
CARECARE
 The primary objectives of the treatment of DVTThe primary objectives of the treatment of DVT
are toare to
 prevent pulmonary embolism,prevent pulmonary embolism,
 reduce morbidity, andreduce morbidity, and
 prevent or minimize the risk of developing theprevent or minimize the risk of developing the
postphlebitic syndrome.postphlebitic syndrome.

 AnticoagulationAnticoagulation
 Thrombolytic therapy for DVTThrombolytic therapy for DVT
 Surgery for DVTSurgery for DVT
 Filters for DVTFilters for DVT
 Compression stockingsCompression stockings

AnticoagulationAnticoagulation
 Heparin prevents extension of the thrombusHeparin prevents extension of the thrombus
 Heparin's anticoagulant effect is related directlyHeparin's anticoagulant effect is related directly
to its activation of antithrombin III.to its activation of antithrombin III.
Antithrombin III, the body's primaryAntithrombin III, the body's primary
anticoagulant, inactivates thrombin and inhibitsanticoagulant, inactivates thrombin and inhibits
the activity of activated factor X in thethe activity of activated factor X in the
coagulation process.coagulation process.

 Heparin is a heterogeneous mixture ofHeparin is a heterogeneous mixture of
polysaccharide fragments with varying molecularpolysaccharide fragments with varying molecular
weights but with similar biological activity. Theweights but with similar biological activity. The
larger fragments primarily interact withlarger fragments primarily interact with
antithrombin III to inhibit thrombin.antithrombin III to inhibit thrombin.
 The low molecular weight fragments exert theirThe low molecular weight fragments exert their
anticoagulant effect by inhibiting the activity ofanticoagulant effect by inhibiting the activity of
activated factor X. The hemorrhagicactivated factor X. The hemorrhagic
complications attributed to heparin are thoughtcomplications attributed to heparin are thought
to arise from the larger higher molecular weightto arise from the larger higher molecular weight
fragmentsfragments..

 The optimal regimen for the treatment of DVTThe optimal regimen for the treatment of DVT
is anticoagulation with heparin or an LMWHis anticoagulation with heparin or an LMWH
followed by full anticoagulation with oralfollowed by full anticoagulation with oral
warfarin for 3-6 monthswarfarin for 3-6 months
 Warfarin therapy is overlapped with heparin forWarfarin therapy is overlapped with heparin for
4-5 days until the INR is therapeutically elevated4-5 days until the INR is therapeutically elevated
to between 2-3.to between 2-3.

 After an initial bolus of 80 U/kg, a constantAfter an initial bolus of 80 U/kg, a constant
maintenance infusion of 18 U/kg is initiated.maintenance infusion of 18 U/kg is initiated.
The aPTT is checked 6 hours after the bolus andThe aPTT is checked 6 hours after the bolus and
adjusted accordingly. .adjusted accordingly. .
 The aPTT is repeated every 6 hours until 2The aPTT is repeated every 6 hours until 2
successive aPTTs are therapeutic. Thereafter, thesuccessive aPTTs are therapeutic. Thereafter, the
aPTT is monitored every 24 hours as well as theaPTT is monitored every 24 hours as well as the
hematocrit and platelet count.hematocrit and platelet count.

Advantages of Low-Molecular-
Weight Heparin Over
Standard Unfractionated Heparin
 Superior bioavailability
 Superior or equivalent safety and efficacy
 Subcutaneous once- or twice-daily dosing
 No laboratory monitoring*
 Less phlebotomy (no monitoring/no intravenous line)
 Less thrombocytopenia
 Earlier/facilitated

At the present time, 3 LMWH preparations,At the present time, 3 LMWH preparations,
 Enoxaparin,Enoxaparin,
 Dalteparin, andDalteparin, and
 ArdeparinArdeparin

warfarinwarfarin
 Interferes with hepatic synthesis of vitamin K-Interferes with hepatic synthesis of vitamin K-
dependent coagulation factorsdependent coagulation factors
 Dose must be individualized and adjusted toDose must be individualized and adjusted to
maintain INR between 2-3maintain INR between 2-3
 2-10 mg/d PO2-10 mg/d PO
 caution in active tuberculosis or diabetes;caution in active tuberculosis or diabetes;
patients with protein C or S deficiency are at riskpatients with protein C or S deficiency are at risk
of developing skin necrosisof developing skin necrosis

Thrombolytic therapy for DVTThrombolytic therapy for DVT
 Advantages includeAdvantages include
 prompt resolution of symptoms,prompt resolution of symptoms,
 prevention of pulmonary embolism,prevention of pulmonary embolism,
 restoration of normal venous circulation,restoration of normal venous circulation,
 preservation of venous valvular function,preservation of venous valvular function,
 and prevention of postphlebitic syndrome.and prevention of postphlebitic syndrome.

Thrombolytic therapy does not preventThrombolytic therapy does not prevent
 clot propagation,clot propagation,
 rethrombosis, orrethrombosis, or
 subsequent embolization.subsequent embolization.
 Heparin therapy and oral anticoagulant therapyHeparin therapy and oral anticoagulant therapy
always must follow a course of thrombolysis.always must follow a course of thrombolysis.

 Thrombolytic therapy is also not effective once theThrombolytic therapy is also not effective once the
thrombus is adherent and begins to organizethrombus is adherent and begins to organize
 The hemorrhagic complications of thrombolyticThe hemorrhagic complications of thrombolytic
therapy are formidable (about 3 times higher),therapy are formidable (about 3 times higher),
including the small but potentially fatal risk ofincluding the small but potentially fatal risk of
intracerebral hemorrhage.intracerebral hemorrhage.
The uncertainty regarding thrombolytic therapy likelyThe uncertainty regarding thrombolytic therapy likely
will continuewill continue

Surgery for DVTSurgery for DVT
 indicationsindications
 when anticoagulant therapy is ineffectivewhen anticoagulant therapy is ineffective
 unsafe,unsafe,
 contraindicated.contraindicated.
 The major surgical procedures for DVT are clotThe major surgical procedures for DVT are clot
removal and partial interruption of the inferiorremoval and partial interruption of the inferior
vena cava to prevent pulmonary embolism.vena cava to prevent pulmonary embolism.

 These pulmonary emboli removed at autopsy look likeThese pulmonary emboli removed at autopsy look like
casts of the deep veins of the leg where they originated.casts of the deep veins of the leg where they originated.


This patient underwent a thrombectomy. The thrombus has beenThis patient underwent a thrombectomy. The thrombus has been
laid over the approximate location in the leg veins where itlaid over the approximate location in the leg veins where it
developed.developed.

Filters for DVTFilters for DVT
 Indications for insertion of an inferior venaIndications for insertion of an inferior vena
cava filtercava filter
 Pulmonary embolism with contraindication toPulmonary embolism with contraindication to
anticoagulationanticoagulation
 Recurrent pulmonary embolism despiteRecurrent pulmonary embolism despite
adequate anticoagulationadequate anticoagulation

 Controversial indications:Controversial indications:
 Deep vein thrombosis with contraindication toDeep vein thrombosis with contraindication to
anticoagulationanticoagulation
 Deep vein thrombosis in patients with pre-Deep vein thrombosis in patients with pre-
existing pulmonary hypertensionexisting pulmonary hypertension
 Free floating thrombus in proximal veinFree floating thrombus in proximal vein
 Failure of existing filter deviceFailure of existing filter device
 Post pulmonary embolectomyPost pulmonary embolectomy

 Inferior vena cava filters reduce the rate ofInferior vena cava filters reduce the rate of
pulmonary embolism but have no effect on thepulmonary embolism but have no effect on the
other complications of deep vein thrombosis.other complications of deep vein thrombosis.
Thrombolysis should be considered in patientsThrombolysis should be considered in patients
with major proximal vein thrombosis andwith major proximal vein thrombosis and
threatened venous infarctionthreatened venous infarction

Compression stockings (routinelyCompression stockings (routinely
recommendedrecommended

Further Inpatient CareFurther Inpatient Care
 Most patients with confirmed proximal vein DVT mayMost patients with confirmed proximal vein DVT may
be treated safely on an outpatient basis. Exclusionbe treated safely on an outpatient basis. Exclusion
criteria for outpatient management are as follows:criteria for outpatient management are as follows:
 Suspected or proven concomitant pulmonary embolismSuspected or proven concomitant pulmonary embolism
 Significant cardiovascular or pulmonary comorbiditySignificant cardiovascular or pulmonary comorbidity
 Morbid obesityMorbid obesity
 Renal failureRenal failure
 Unavailable or unable to arrange close follow-up careUnavailable or unable to arrange close follow-up care

 Patients are treated with a low molecular weightPatients are treated with a low molecular weight
heparin and instructed to initiate therapy with warfarinheparin and instructed to initiate therapy with warfarin
5 mg PO the next day. Low molecular weight heparin5 mg PO the next day. Low molecular weight heparin
and warfarin are overlapped for about 5 days until theand warfarin are overlapped for about 5 days until the
international normalized ratio (INR) is therapeutic.international normalized ratio (INR) is therapeutic.
 If inpatient treatment is necessary, low molecularIf inpatient treatment is necessary, low molecular
weight heparin is effective and obviates the need forweight heparin is effective and obviates the need for
IV infusions or serial monitoring of the PTT.IV infusions or serial monitoring of the PTT.
 With the introduction of low molecular weightWith the introduction of low molecular weight
heparin, selected patients qualify for outpatientheparin, selected patients qualify for outpatient
treatment only if adequate home care and closetreatment only if adequate home care and close
medical follow-up care can be arranged.medical follow-up care can be arranged.

 Platelets also should be monitored and heparinPlatelets also should be monitored and heparin
discontinued if platelets fall below 75,000.discontinued if platelets fall below 75,000.
 While on warfarin, the prothrombin time (PT) mustWhile on warfarin, the prothrombin time (PT) must
be monitored daily until target achieved, then weeklybe monitored daily until target achieved, then weekly
for several weeks. When the patient is stable, monitorfor several weeks. When the patient is stable, monitor
monthly.monthly.
 Significant bleeding (ie, hematemesis, hematuria,Significant bleeding (ie, hematemesis, hematuria,
gastrointestinal hemorrhage) should be investigatedgastrointestinal hemorrhage) should be investigated
thoroughly since anticoagulant therapy may unmask athoroughly since anticoagulant therapy may unmask a
preexisting disease (eg, cancer, peptic ulcer disease,preexisting disease (eg, cancer, peptic ulcer disease,
arteriovenous malformation).arteriovenous malformation).

Duration of anticoagulation in patientsDuration of anticoagulation in patients
with deep vein thrombosiswith deep vein thrombosis
 Transient cause and no other risk factors: 3 monthsTransient cause and no other risk factors: 3 months
 Idiopathic: 3-6 monthsIdiopathic: 3-6 months
 Ongoing risk for example, malignancy: 6 -12 monthsOngoing risk for example, malignancy: 6 -12 months
 Recurrent pulmonary embolism or deep veinRecurrent pulmonary embolism or deep vein
thrombosis: 6-12 monthsthrombosis: 6-12 months
 Patients with high risk of recurrent thrombosisPatients with high risk of recurrent thrombosis
exceeding risk of anticoagulation: indefinite durationexceeding risk of anticoagulation: indefinite duration
(subject to review)(subject to review)

Further Outpatient Care:Further Outpatient Care:
 Patients with suspected or diagnosed isolatedPatients with suspected or diagnosed isolated
calf vein DVT may be discharged safely on acalf vein DVT may be discharged safely on a
nonsteroidal anti-inflammatory drug (NSAID)nonsteroidal anti-inflammatory drug (NSAID)
or aspirin with close follow-up care and repeator aspirin with close follow-up care and repeat
diagnostic studies in 3-7 days to detect proximaldiagnostic studies in 3-7 days to detect proximal
extension.extension.
 At certain centers, patients with isolated calfAt certain centers, patients with isolated calf
vein DVT are admitted for full anticoagulantvein DVT are admitted for full anticoagulant
therapy.therapy.

 Patients with suspected DVT but negativePatients with suspected DVT but negative
noninvasive studies need to be reassessed bynoninvasive studies need to be reassessed by
their primary care provider within 3-7 days.their primary care provider within 3-7 days.
 Patients with ongoing risk factors may need toPatients with ongoing risk factors may need to
be restudied at that time to detect proximalbe restudied at that time to detect proximal
extension because of the limited accuracy ofextension because of the limited accuracy of
noninvasive tests for calf vein DVT.noninvasive tests for calf vein DVT.

ComplicationsComplications
 Acute pulmonary embolismAcute pulmonary embolism
 Hemorrhagic complicationsHemorrhagic complications
 Chronic venous insufficiencyChronic venous insufficiency

Prognosis:Prognosis:
 All patients with proximal vein DVT are at long-All patients with proximal vein DVT are at long-
term risk of developing chronic venousterm risk of developing chronic venous
insufficiency.insufficiency.
 About 20% of untreated proximal (above theAbout 20% of untreated proximal (above the
calf) DVTs progress to pulmonary emboli, andcalf) DVTs progress to pulmonary emboli, and
10-20% of these are fatal. With aggressive10-20% of these are fatal. With aggressive
anticoagulant therapy, the mortality is decreasedanticoagulant therapy, the mortality is decreased
5- to 10-fold.5- to 10-fold.
 DVT confined to the calf virtually never causesDVT confined to the calf virtually never causes
clinically significant emboli and thus does notclinically significant emboli and thus does not
require anticoagulationrequire anticoagulation

Patient Education:Patient Education:
 Advise women taking estrogen of the risks andAdvise women taking estrogen of the risks and
common symptoms of thromboembolic disease.common symptoms of thromboembolic disease.
 Discourage prolonged immobility, particularlyDiscourage prolonged immobility, particularly
on plane rides and long car tripson plane rides and long car trips

PROPHYLAXISPROPHYLAXIS
 Ideidentify any patiant who is at risk.Ideidentify any patiant who is at risk.
 Prevent dehydration.Prevent dehydration.
 During operation avoid prolonged calf compression.During operation avoid prolonged calf compression.
 Passive leg exercises should be encourged whilst patientPassive leg exercises should be encourged whilst patient
on bed.on bed.
 Foot of bed should be elevated to increase venousFoot of bed should be elevated to increase venous
return.return.
 Early mobilization should be rule for all surgical patients.Early mobilization should be rule for all surgical patients.

Deep Vein Thrombosis Guide

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