DEEP VENOUS DEEP VENOUS THROMBOSISTHROMBOSIS

DR.FAZAL HUSSAIN KHALILDR.FAZAL HUSSAIN KHALIL

Definition Definition

Deep vein thrombosis is the Deep vein thrombosis is the formation of a blood clot in formation of a blood clot in one of the deep veins of the one of the deep veins of the body, usually in the legbody, usually in the leg

ETIOLOGY ETIOLOGY

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

Virchow tried Virchow tried

More than 100 years ago, Virchow More than 100 years ago, Virchow described a triad of factors of described a triad of factors of

venous stasis, venous stasis, endothelial damage, andendothelial damage, and hypercoagulable statehypercoagulable state

Venous stasis Venous stasis

prolonged bed rest (4 days or more) prolonged bed rest (4 days or more) A cast on the leg A cast on the leg Limb paralysis from stroke or spinal Limb paralysis from stroke or spinal

cord injury cord injury extended travel in a vehicle extended travel in a vehicle

Hypercoagulability Hypercoagulability

Surgery and trauma responsible for up to Surgery and trauma responsible for up to 40% of all thromboembolic disease 40% of all thromboembolic disease

Malignancy Malignancy Increased estrogen (due to a fall in protein Increased estrogen (due to a fall in protein

‘S) Increased estrogen occurs during ‘S) Increased estrogen 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 during treatment with oral contraceptive

pills pills

Inherited disorders of Inherited disorders of coagulation coagulation

deficiencies of protein ‘S,deficiencies of protein ‘S, ’ ’ protein ‘C,’ andprotein ‘C,’ and antithrombin III. antithrombin III.

Acquired disorders of Acquired disorders of coagulation coagulation

nephrotic syndrome results in nephrotic syndrome results in urinary loss of antithrombin III, this urinary loss of antithrombin III, this diagnosis should be considered in diagnosis should be considered in children presenting with children presenting with thromboembolic disease thromboembolic disease

Antiphospholipid antibodies Antiphospholipid antibodies accelerate coagulation and include accelerate coagulation and include the lupus anticoagulant and the lupus anticoagulant and anticardiolipin antibodies.anticardiolipin antibodies.

Inflammatory processes, such asInflammatory processes, such as• systemic lupus erythematosus (SLE),systemic lupus erythematosus (SLE),

• sickle cell disease, and sickle cell disease, and •inflammatory bowel disease (IBD), inflammatory bowel disease (IBD),

also predispose to thrombosis, presumably also predispose to thrombosis, presumably due to hypercoagulability due to hypercoagulability

Endothelial Injury Endothelial Injury Trauma,Trauma, surgery, andsurgery, and invasive procedure may disrupt venous invasive procedure may disrupt venous

integrity integrity Iatrogenic causes of venous thrombosis Iatrogenic causes of venous thrombosis

are increasing due to the widespread use are increasing due to the widespread use of central venous catheters, particularly of central venous catheters, particularly subclavian and internal jugular lines. subclavian and internal jugular lines. These lines are an important cause of These lines are an important cause of upper extremity DVT, particularly in upper extremity DVT, particularly in children. children.

Clinical Pathophysiology Clinical Pathophysiology

The nidus for a clot is often an The nidus for a clot is often an intimal defect intimal defect

When a clot forms on an intimal When a clot forms on an intimal defect, the coagulation cascade defect, the coagulation cascade promotes clot growth proximally. promotes clot growth proximally. Thrombus can extend from the Thrombus can extend from the superficial veins into the deep superficial veins into the deep system from which it can embolize system from which it can embolize to the lungs. to the lungs.

Opposing the coagulation cascade is the Opposing the coagulation cascade is the endogenous fibrinolytic system. After endogenous fibrinolytic system. After the clot organizes or dissolves, most the clot organizes or dissolves, most veins will recanalize in several weeks. veins will recanalize in several weeks. Residual clots retract as fibroblasts and Residual clots retract as fibroblasts and capillary development lead to intimal capillary development lead to intimal thickening.thickening.

Venous hypertension and residual clot Venous hypertension and residual clot may destroy valves, leading to the may destroy valves, leading to the postphlebitic syndrome, which develops postphlebitic syndrome, which develops within 5-10 years within 5-10 years

Edema, sclerosis, and ulceration Edema, sclerosis, and ulceration characterize this syndrome, which characterize this syndrome, which develops in 40-80% of patients with DVT.develops in 40-80% of patients with DVT.

patients also can suffer exacerbations of patients also can suffer exacerbations of swelling and pain, probably as a result of swelling and pain, probably as a result of venous dilatation and hypertension venous dilatation and hypertension

          Pulmonary embolism (PE) is a serious Pulmonary embolism (PE) is a serious complication of DVT. Many episodes of complication of DVT. Many episodes of pulmonary embolism go unrecognized, pulmonary embolism go unrecognized, and at least 40% of patients with DVT and at least 40% of patients with DVT have clinically silent PE on VQ scanninghave clinically silent PE on VQ scanning

Presentation and Physical Presentation and Physical Examination Examination

Calf pain or tenderness, or both Calf pain or tenderness, or both Swelling with pitting oedema Swelling with pitting oedema Swelling below knee in distal deep vein Swelling below knee in distal deep vein

thrombosis and up to groin in proximal thrombosis and up to groin in proximal deep vein thrombosis deep vein thrombosis

Increased skin temperature Increased skin temperature Superficial venous dilatation Superficial venous dilatation Cyanosis can occur with severe Cyanosis can occur with severe

obstructionobstruction

Palpate distal pulses and evaluate Palpate distal pulses and evaluate capillary refill to assess limb perfusion. capillary refill to assess limb perfusion.

Move and palpate all joints to detect Move and palpate all joints to detect acute arthritis or other joint pathology. acute arthritis or other joint pathology.

Neurologic evaluation may detect Neurologic evaluation may detect nerve root irritation; sensory, motor, nerve root irritation; sensory, motor, and reflex deficits should be noted and reflex deficits should be noted

Homans'’ sign: pain in the posterior Homans'’ sign: pain in the posterior calf or knee with forced dorsiflexion of calf or knee with forced dorsiflexion of the foot the foot

Search for stigmata of PE such as Search for stigmata of PE such as tachycardia (common), tachypnea or tachycardia (common), tachypnea or chest findings (rare), and chest findings (rare), and

exam for signs suggestive of exam for signs suggestive of underlying predisposing factors.underlying predisposing factors.

Wells Clinical Prediction Wells Clinical Prediction GuideGuide

The Wells clinical prediction guide The Wells clinical prediction guide incorporates risk factors, clinical signs, and incorporates risk factors, clinical signs, and the presence or absence of alternative the presence or absence of alternative diagnosesdiagnoses

. . Wells Clinical Prediction Guide for Wells Clinical Prediction Guide for DVTClinical ParameterScoreDVTClinical ParameterScore

Active cancer (treatment ongoing, or within Active cancer (treatment ongoing, or within 6 months or palliative)16 months or palliative)1

Paralysis or recent plaster immobilization 1Paralysis or recent plaster immobilization 1 Recently bedridden for >3 days or major Recently bedridden for >3 days or major

surgery <4 weeks1surgery <4 weeks1

Localized tenderness along the distribution of Localized tenderness along the distribution of the deep venous system1the deep venous system1

Entire leg swelling1Entire leg swelling1 Calf swelling >3 cm compared to the Calf swelling >3 cm compared to the

asymptomatic leg 1asymptomatic leg 1 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 Alternative diagnosis (as likely or > that of

DVT)DVT)

Total of Above ScoreTotal of Above Score

High probability: Score ³3High probability: Score ³3Moderate probability: Score = 1 or 2Moderate probability: Score = 1 or 2Low probability: Score £0 Low probability: Score £0

Adapted from Anand SS, et al. Adapted from Anand SS, et al. JAMAJAMA. . 1998; 279 [14];10941998; 279 [14];1094

Diagnostic Studies Diagnostic Studies

Clinical examination alone is able to Clinical examination alone is able to confirm only 20-30% of cases of DVT confirm only 20-30% of cases of DVT

Blood Tests Blood Tests the D-dimerthe D-dimer INR. INR. Current D-dimer assays have predictive Current D-dimer assays have predictive

value for DVT, and thevalue for DVT, and the INR is useful for guiding the management INR is useful for guiding the management

of patients with known DVT who are on of patients with known DVT who are on warfarin (Coumadin) warfarin (Coumadin)

D-dimer D-dimer D-dimer is a specific degradation product D-dimer is a specific degradation product

of cross-linked fibrin. Because concurrent of cross-linked fibrin. Because concurrent production and breakdown of clot production and breakdown of clot characterize thrombosis, patients with characterize thrombosis, patients with thromboembolic disease have elevated thromboembolic disease have elevated levels of D-dimer levels of D-dimer

three major approaches for measuring D-three major approaches for measuring D-dimer dimer

ELISA ELISA latex agglutination latex agglutination blood agglutination test (SimpliRED blood agglutination test (SimpliRED

False-positive D-dimers occur in patients False-positive D-dimers occur in patients withwith

recent (within 10 days) surgery or recent (within 10 days) surgery or trauma,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 active collagen vascular disease, or

metastatic cancer metastatic cancer

Imaging Studies Imaging Studies

InvasiveInvasive venography, venography, radiolabeled fibrinogen and.radiolabeled fibrinogen and. noninvasive noninvasive ultrasound, ultrasound, plethysmography, plethysmography, MRI techniques MRI techniques

venographyvenography

gold standard” modality for the gold standard” modality for the diagnosis of DVT diagnosis of DVT

Advantages Advantages Venography is also useful if the patient Venography is also useful if the patient

has a high clinical probability of has a high clinical probability of thrombosis and a negative ultrasound, thrombosis and a negative ultrasound,

it is also valuable in symptomatic it is also valuable in symptomatic patients with a history of prior patients with a history of prior thrombosis in whom the ultrasound is thrombosis in whom the ultrasound is non-diagnostic. non-diagnostic.

side effects side effects

phlebitis phlebitis anaphylaxis anaphylaxis

Nuclear Medicine Nuclear Medicine Studies Studies

Because the radioactive isotope Because the radioactive isotope incorporates into a growing incorporates into a growing thrombus, this test can distinguish thrombus, this test can distinguish new clot fromnew clot from an old clot an old clot

Plethysmography Plethysmography

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

Ultrasonography Ultrasonography

color-flow Duplex scanning is the imaging color-flow Duplex scanning is the imaging test of choice for patients with suspected test of choice for patients with suspected DVT DVT

inexpensive,inexpensive, noninvasive, noninvasive, widely available widely available Ultrasound can also distinguish other Ultrasound can also distinguish other

causes of leg swelling, such as tumor, causes of leg swelling, such as tumor, popliteal cyst, abscess, aneurysm, or popliteal cyst, abscess, aneurysm, or hematoma.     hematoma.     

clinical limitations clinical limitations

expensive expensive reader dependent reader dependent Duplex scans are less likely to detect Duplex scans are less likely to detect

non-occluding thrombi. non-occluding thrombi. During the second half of pregnancy, During the second half of pregnancy,

ultrasound becomes less specific, ultrasound becomes less specific, because the gravid uterus compresses because the gravid uterus compresses the inferior vena cava, thereby changing the inferior vena cava, thereby changing Doppler flow in the lower extremities Doppler flow in the lower extremities

Magnetic Resonance Magnetic Resonance Imaging Imaging

It detects leg, pelvis, and pulmonary It detects leg, pelvis, and pulmonary thrombi and is 97% sensitive and 95% thrombi and is 97% sensitive and 95% specific for DVT.specific for DVT.

It distinguishes a mature from an It distinguishes a mature from an immature clot.immature clot.

MRI is safe in all stages of MRI is safe in all stages of pregnancy. pregnancy.

DIFFERENTIAL DIFFERENTIAL DIAGNOSISDIAGNOSIS

o Cellulitis ThrombophlebitisThrombophlebitis

o ArthritisArthritisAsymmetric peripheral edema secondary to Asymmetric peripheral edema secondary to CHF, liver disease, renal failure, or CHF, liver disease, renal failure, or nephrotic syndromenephrotic syndrome lymphangitis lymphangitisExtrinsic compression of iliac vein secondary Extrinsic compression of iliac vein secondary to tumor, hematoma, or abscessto tumor, hematoma, or abscessHematomaHematomaLymphedemaLymphedema

Muscle or soft tissue injuryMuscle or soft tissue injuryNeurogenic painNeurogenic painPostphlebitic syndrome Postphlebitic syndrome Prolonged immobilization or limb Prolonged immobilization or limb paralysisparalysisRuptured Baker cystRuptured Baker cystStress fractures or other bony lesionsStress fractures or other bony lesionsSuperficial thrombophlebitisSuperficial thrombophlebitisVaricose veins Varicose veins

ManagementManagement

Using the pretest probability score Using the pretest probability score calculated from the Wells Clinical calculated from the Wells Clinical Prediction rule, patients are Prediction rule, patients are stratified into 3 risk groups—high, stratified into 3 risk groups—high, moderate, or low. moderate, or low.

The results from duplex ultrasound The results from duplex ultrasound are incorporated as follows: are incorporated as follows:

If the patient is high or moderate If the patient is high or moderate risk and the duplex ultrasound study risk and the duplex ultrasound study is positive, treat for DVT. is positive, treat for DVT.

If the duplex study is negative and the If the duplex study is negative and the patient is low risk, DVT has been ruled patient is low risk, DVT has been ruled out. out.

• When discordance exists between the When discordance exists between the pretest probability and the duplex study pretest probability and the duplex study result, further evaluation is required. result, further evaluation is required.

If the patient is high risk but the If the patient is high risk but the ultrasound study was negative, the ultrasound study was negative, the patient still has a significant probability patient still has a significant probability of DVTof DVT

a venogram to rule out a calf vein DVT a venogram to rule out a calf vein DVT surveillance with repeat clinical surveillance with repeat clinical

evaluation and ultrasound in 1 week. evaluation and ultrasound in 1 week. results of a D-dimer assay to guide results of a D-dimer assay to guide

managementmanagement If the patient is low risk but the If the patient is low risk but the

ultrasound study is positive, some authors ultrasound study is positive, some authors recommend a second confirmatory study recommend a second confirmatory study such as a venogram before treating for such as a venogram before treating for DVT DVT

EMERGENCY EMERGENCY DEPARTMANT CAREDEPARTMANT CARE

The primary objectives of the The primary objectives of the treatment of DVT are to treatment of DVT are to

prevent pulmonary embolism, prevent pulmonary embolism, reduce morbidity, andreduce morbidity, and prevent or minimize the risk of prevent or minimize the risk of

developing the postphlebitic developing the postphlebitic syndrome. syndrome.

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

AnticoagulationAnticoagulation

Heparin prevents extension of the Heparin prevents extension of the thrombus thrombus

Heparin's anticoagulant effect is Heparin's anticoagulant effect is related directly to its activation of related directly to its activation of antithrombin III. Antithrombin III, antithrombin III. Antithrombin III, the body's primary anticoagulant, the body's primary anticoagulant, inactivates thrombin and inhibits the inactivates thrombin and inhibits the activity of activated factor X in the activity of activated factor X in the coagulation process. coagulation process.

Heparin is a heterogeneous mixture of Heparin is a heterogeneous mixture of polysaccharide fragments with varying polysaccharide fragments with varying molecular weights but with similar molecular weights but with similar biological activity. The larger fragments biological activity. The larger fragments primarily interact with antithrombin III to primarily interact with antithrombin III to inhibit thrombin.inhibit thrombin.

The low molecular weight fragments The low molecular weight fragments exert their anticoagulant effect by exert their anticoagulant effect by inhibiting the activity of activated factor inhibiting the activity of activated factor X. The hemorrhagic complications X. The hemorrhagic complications attributed to heparin are thought to arise attributed to heparin are thought to arise from the larger higher molecular weight from the larger higher molecular weight fragmentsfragments. .

The optimal regimen for the The optimal regimen for the treatment of DVT is anticoagulation treatment of DVT is anticoagulation with heparin or an LMWH followed with heparin or an LMWH followed by full anticoagulation with oral by full anticoagulation with oral warfarin for 3-6 months warfarin for 3-6 months

Warfarin therapy is overlapped with Warfarin therapy is overlapped with heparin for 4-5 days until the INR is heparin for 4-5 days until the INR is therapeutically elevated to between therapeutically elevated to between 2-3. 2-3.

After an initial bolus of 80 U/kg, a After an initial bolus of 80 U/kg, a constant maintenance infusion of 18 constant maintenance infusion of 18 U/kg is initiated. The aPTT is checked 6 U/kg is initiated. The aPTT is checked 6 hours after the bolus and adjusted hours after the bolus and adjusted accordingly. .accordingly. .

The aPTT is repeated every 6 hours The aPTT is repeated every 6 hours until 2 successive aPTTs are until 2 successive aPTTs are therapeutic. Thereafter, the aPTT is therapeutic. Thereafter, the aPTT is monitored every 24 hours as well as the monitored every 24 hours as well as the hematocrit and platelet count. hematocrit and platelet count.

Advantages of Low-Molecular-Weight Heparin

OverStandard 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 At the present time, 3 LMWH preparations, preparations,

Enoxaparin,Enoxaparin, Dalteparin, andDalteparin, and Ardeparin Ardeparin

warfarin warfarin

Interferes with hepatic synthesis of Interferes with hepatic synthesis of vitamin K-dependent coagulation factors vitamin K-dependent coagulation factors

Dose must be individualized and Dose must be individualized and adjusted to maintain INR between 2-3 adjusted to maintain INR between 2-3

2-10 mg/d PO 2-10 mg/d PO caution in active tuberculosis or caution in active tuberculosis or

diabetes; patients with protein C or S diabetes; patients with protein C or S deficiency are at risk of developing skin deficiency are at risk of developing skin necrosis necrosis

Thrombolytic therapy for Thrombolytic therapy for DVTDVT

Advantages include Advantages include prompt resolution of symptoms, prompt resolution of symptoms, prevention of pulmonary embolism, prevention of pulmonary embolism, restoration of normal venous restoration of normal venous

circulation, circulation, preservation of venous valvular preservation of venous valvular

function, function, and prevention of postphlebitic and prevention of postphlebitic

syndrome. syndrome.

Thrombolytic therapy does not Thrombolytic therapy does not prevent prevent

clot propagation,clot propagation, rethrombosis, orrethrombosis, or subsequent embolization.subsequent embolization. Heparin therapy and oral Heparin therapy and oral

anticoagulant therapy always must anticoagulant therapy always must follow a course of thrombolysis. follow a course of thrombolysis.

Thrombolytic therapy is also not effective Thrombolytic therapy is also not effective once the thrombus is adherent and once the thrombus is adherent and begins to organize begins to organize

The hemorrhagic complications of The hemorrhagic complications of thrombolytic therapy are formidable thrombolytic therapy are formidable (about 3 times higher), including the (about 3 times higher), including the small but potentially fatal risk of small but potentially fatal risk of intracerebral hemorrhage.intracerebral hemorrhage.

The uncertainty regarding thrombolytic The uncertainty regarding thrombolytic therapy likely will continue therapy likely will continue

Surgery for DVT Surgery for DVT

indicationsindications when anticoagulant therapy is when anticoagulant therapy is

ineffectiveineffective unsafe, unsafe, contraindicated. contraindicated. The major surgical procedures for The major surgical procedures for

DVT are clot removal and partial DVT are clot removal and partial interruption of the inferior vena cava interruption of the inferior vena cava to prevent pulmonary embolism. to prevent pulmonary embolism.

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

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

Filters for DVT Filters for DVT

Indications for insertion of an Indications for insertion of an inferior vena cava filterinferior vena cava filter

Pulmonary embolism with Pulmonary embolism with contraindication to anticoagulation contraindication to anticoagulation

Recurrent pulmonary embolism Recurrent pulmonary embolism despite adequate anticoagulation despite adequate anticoagulation

Controversial indications:Controversial indications: Deep vein thrombosis with Deep vein thrombosis with

contraindication to anticoagulation contraindication to anticoagulation Deep vein thrombosis in patients with Deep vein thrombosis in patients with

pre-existing pulmonary hypertension pre-existing pulmonary hypertension Free floating thrombus in proximal vein Free floating thrombus in proximal vein Failure of existing filter device Failure of existing filter device Post pulmonary embolectomyPost pulmonary embolectomy

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

Compression stockings Compression stockings (routinely recommended (routinely recommended

Further Inpatient Care Further Inpatient Care Most patients with confirmed proximal vein DVT Most patients with confirmed proximal vein DVT

may be treated safely on an outpatient basis. may be treated safely on an outpatient basis. Exclusion criteria for outpatient management are as Exclusion criteria for outpatient management are as follows: follows:

Suspected or proven concomitant pulmonary Suspected or proven concomitant pulmonary embolism embolism

Significant cardiovascular or pulmonary Significant cardiovascular or pulmonary comorbidity comorbidity

Morbid obesity Morbid obesity Renal failure Renal failure Unavailable or unable to arrange close follow-up Unavailable or unable to arrange close follow-up

carecare

Patients are treated with a low molecular Patients are treated with a low molecular weight heparin and instructed to initiate weight heparin and instructed to initiate therapy with warfarin 5 mg PO the next day. therapy with warfarin 5 mg PO the next day. Low molecular weight heparin and warfarin are Low molecular weight heparin and warfarin are overlapped for about 5 days until the overlapped for about 5 days until the international normalized ratio (INR) is international normalized ratio (INR) is therapeutic. therapeutic.

If inpatient treatment is necessary, low If inpatient treatment is necessary, low molecular weight heparin is effective and molecular weight heparin is effective and obviates the need for IV infusions or serial obviates the need for IV infusions or serial monitoring of the PTT.monitoring of the PTT.

With the introduction of low molecular weight With the introduction of low molecular weight heparin, selected patients qualify for outpatient heparin, selected patients qualify for outpatient treatment only if adequate home care and close treatment 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 Platelets also should be monitored and heparin discontinued if platelets fall below heparin discontinued if platelets fall below 75,000. 75,000.

While on warfarin, the prothrombin time While on warfarin, the prothrombin time (PT) must be monitored daily until target (PT) must be monitored daily until target achieved, then weekly for several weeks. achieved, then weekly for several weeks. When the patient is stable, monitor When the patient is stable, monitor monthly. monthly.

Significant bleeding (ie, hematemesis, Significant bleeding (ie, hematemesis, hematuria, gastrointestinal hemorrhage) hematuria, gastrointestinal hemorrhage) should be investigated thoroughly since should be investigated thoroughly since anticoagulant therapy may unmask a anticoagulant therapy may unmask a preexisting disease (eg, cancer, peptic preexisting disease (eg, cancer, peptic ulcer disease, arteriovenous malformation). ulcer disease, arteriovenous malformation).

Duration of anticoagulation in Duration of anticoagulation in patients with deep vein patients with deep vein

thrombosisthrombosis Transient cause and no other risk factors: Transient cause and no other risk factors:

3 months 3 months Idiopathic: 3-6 months Idiopathic: 3-6 months Ongoing risk for example, malignancy: 6 -Ongoing risk for example, malignancy: 6 -

12 months 12 months Recurrent pulmonary embolism or deep vein Recurrent pulmonary embolism or deep vein

thrombosis: 6-12 months thrombosis: 6-12 months Patients with high risk of recurrent thrombosis Patients with high risk of recurrent thrombosis

exceeding risk of anticoagulation: indefinite exceeding risk of anticoagulation: indefinite duration (subject to review)duration (subject to review)

Further Outpatient Care: Further Outpatient Care:

Patients with suspected or diagnosed Patients with suspected or diagnosed isolated calf vein DVT may be isolated calf vein DVT may be discharged safely on a nonsteroidal discharged safely on a nonsteroidal anti-inflammatory drug (NSAID) or anti-inflammatory drug (NSAID) or aspirin with close follow-up care and aspirin with close follow-up care and repeat diagnostic studies in 3-7 days repeat diagnostic studies in 3-7 days to detect proximal extension.to detect proximal extension.

At certain centers, patients with At certain centers, patients with isolated calf vein DVT are admitted isolated calf vein DVT are admitted for full anticoagulant therapy.for full anticoagulant therapy.

Patients with suspected DVT but Patients with suspected DVT but negative noninvasive studies need to negative noninvasive studies need to be reassessed by their primary care be reassessed by their primary care provider within 3-7 days.provider within 3-7 days.

Patients with ongoing risk factors Patients with ongoing risk factors may need to be restudied at that may need to be restudied at that time to detect proximal extension time to detect proximal extension because of the limited accuracy of because of the limited accuracy of noninvasive tests for calf vein DVT.noninvasive tests for calf vein DVT.

Complications Complications

Acute pulmonary embolismAcute pulmonary embolism Hemorrhagic complications Hemorrhagic complications Chronic venous insufficiencyChronic venous insufficiency

Prognosis: Prognosis:

All patients with proximal vein DVT are All patients with proximal vein DVT are at long-term risk of developing chronic at long-term risk of developing chronic venous insufficiency.venous insufficiency.

About 20% of untreated proximal About 20% of untreated proximal (above the calf) DVTs progress to (above the calf) DVTs progress to pulmonary emboli, and 10-20% of these pulmonary emboli, and 10-20% of these are fatal. With aggressive anticoagulant are fatal. With aggressive anticoagulant therapy, the mortality is decreased 5- therapy, the mortality is decreased 5- to 10-fold.to 10-fold.

DVT confined to the calf virtually never DVT confined to the calf virtually never causes clinically significant emboli and causes clinically significant emboli and thus does not require anticoagulationthus does not require anticoagulation

Patient Education: Patient Education:

Advise women taking estrogen of the Advise women taking estrogen of the risks and common symptoms of risks and common symptoms of thromboembolic disease.thromboembolic disease.

Discourage prolonged immobility, Discourage prolonged immobility, particularly on plane rides and long particularly on plane rides and long car tripscar 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 During operation avoid prolonged calf

compression.compression. Passive leg exercises should be encourged Passive leg exercises should be encourged

whilst patient on bed.whilst patient on bed. Foot of bed should be elevated to increase Foot of bed should be elevated to increase

venous return.venous return. Early mobilization should be rule for all Early mobilization should be rule for all

surgical patients.surgical patients.