dvt_2 faiza

8/4/2019 dvt_2 faiza

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DR FAIZA GHUMAN

RESIDENT, MED 4,CHK.



37 yo moderately obese female onOCP presents to ER with a two dayhistory of painless R leg swelling.She’s been elevating her leg several

days after a severe ankle sprain duringa mother-daughter soccer game.

No prior medical history, recentsurgery or weight loss. She is a non-smoker and drinks rarely.

Exam is notable for R ankle splint andpitting edema in R calf, which is 1.5 cmlarger than the L.





Deep vein thrombosis is theformation of a blood clot in one ofthe deep veins of the body, usually

in the leg



DVT ususally originates in the lowerextremity venous level ,starting at the calf

vein level and progressing proximally toinvolve popliteal ,femoral ,or iliac system. .80-90 % pulmonary emboli originates here .



More than 100 years ago, Virchow described atriad of factors of

venous stasis, endothelial damage, and hypercoagulable state



General- Age- Immobilization > 3d- Pregnancy / post-partum

- Major surgery < 4 weeks- Trip (>4h) in past 4 weeks

Medical- Cancer- Previous DVT

- CHF- Sepsis- Nephrotic syndrome

Trauma- CNS / spinal cord injury- Burns- Lower extremity fractures

Hematologic- Thrombocytosis- Anti-thrombin III deficiency- Protein C deficiency- Protein S deficiency

- Factor V Leiden Drugs

- OCP- Estrogens



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

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

also predispose to thrombosis, presumably due tohypercoagulability



Trauma, surgery, and invasive procedure may disrupt venous

integrity Iatrogenic causes of venous thrombosis are

increasing due to the widespread use of

central venous catheters, particularlysubclavian and internal jugular lines. Theselines are an important cause of upperextremity DVT, particularly in children.



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

thrombosis and up to groin in proximal deepvein thrombosis

Increased skin temperature

Superficial venous dilatation Cyanosis can occur with severe obstruction



Palpate distal pulses and evaluate capillaryrefill to assess limb perfusion.

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

Neurologic evaluation may detect nerve rootirritation; sensory, motor, and reflex deficits

should be noted Homans'’ sign: pain in the posterior calf or

knee with forced dorsiflexion of the foot



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

and exam for signs suggestive of underlying

predisposing factors.



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Clinical Parameter Score

Active cancer +1

Paralysis or recent immobilization of extremities +1

Recently bedridden for > 3 days or major surgery <4 weeks +1

Tenderness along distribution of deep venous system +1

Entire leg swollen +1

Calf swelling > 3cm circumference difference from unaffected leg +1

Pitting edema +1

Previous DVT +1

Collateral superficial veins +1

Alternative diagnosis as likely or more likely than DVT -2

High Probability ≥ 3

Moderate Probability 1 or 2

Low Probabillity 0



D-dimer is a specific degradation product of cross-linked fibrin. Because concurrentproduction and breakdown of clot

characterize thrombosis, patients withthromboembolic disease have elevated levelsof D-dimer

three major approaches for measuring D-

dimer ELISA latex agglutination blood agglutination test (SimpliRED



False-positive D-dimers occur in patients with recent (within 10 days) surgery or trauma, recent myocardial infarction or stroke, acute infection, disseminated intravascular coagulation, pregnancy or recent delivery,

active collagen vascular disease, ormetastatic cancer





Study Notes

Contrast Venography - “Gold standard”, 99% sensitive- Allergic reaction, availability,IV contrast, costly

- Good for calf, iliac veins, IVC

MRI - Useful in pregnancy- Can distinguish acute from chronic- Good for calf, iliac veins- Cost, accessibility

CT - Can do PE study at same time

- Good for calf, iliac veinsDuplex Ultrasonography - No radiation, bedside, cost

- Non-occlusive thrombi- Cannot distinguish acute from chronic- Poor visualization of calf, iliac veins



Invasive venography,

radiolabeled fibrinogen and. noninvasiveultrasound,plethysmography,MRI techniques



gold standard” modality for the diagnosis of DVT

Advantages Venography is also useful if the patient has a

high clinical probability of thrombosis and anegative ultrasound,

it is also valuable in symptomatic patientswith a history of prior thrombosis in whomthe ultrasound is non-diagnostic.



phlebitis anaphylaxis






Because the radioactive isotope incorporatesinto a growing thrombus, this test candistinguish new clot from an old clot



Plethysmography measures change in lowerextremity volume in response to certain

stimuli.



color-flow Duplex scanning is the imagingtest of choice for patients with suspected

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

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





expensive reader dependent

Duplex scans are less likely to detect non-occluding thrombi. During the second half of pregnancy,

ultrasound becomes less specific, becausethe gravid uterus compresses the inferiorvena cava, thereby changing Doppler flow inthe lower extremities



It detects leg, pelvis, and pulmonary thrombiand is 97% sensitive and 95% specific for DVT. It distinguishes a mature from an immature

clot. MRI is safe in all stages of pregnancy.



Cellulitis Thrombophlebitis Arthritis

Asymmetric peripheral edema secondary to CHF,liver disease, renal failure, or nephrotic syndromelymphangitis

Extrinsic compression of iliac vein secondary to

tumor, hematoma, or abscess Hematoma Lymphedema

http://www.emedicine.com/EMERG/topic88.htm

http://www.emedicine.com/EMERG/topic88.htm



Muscle or soft tissue injury Neurogenic pain Postphlebitic syndrome Prolonged immobilization or limb paralysis

Ruptured Baker cyst Stress fractures or other bony lesions

Superficial thrombophlebitis Varicose veins



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

The results from duplex ultrasound areincorporated as follows:

If the patient is high or moderate risk and theduplex ultrasound study is positive, treat forDVT.



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

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

If the patient is high risk but the ultrasound

study was negative, the patient still has asignificant probability of DVT



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

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

management If the patient is low risk but the ultrasound

study is positive, some authors recommend asecond confirmatory study such as avenogram before treating for DVT



The primary objectives of the treatment of DVT are to

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

the postphlebitic syndrome.



Anticoagulation Thrombolytic therapy for DVT

Surgery for DVT Filters for DVT Compression stockings



Heparin prevents extension of the thrombus Heparin's anticoagulant effect is related

directly to its activation of antithrombin III.Antithrombin III, the body's primaryanticoagulant, inactivates thrombin andinhibits the activity of activated factor X in

the coagulation process.

Heparin is a heterogeneous mixture of



Heparin is a heterogeneous mixture of polysaccharide fragments with varyingmolecular weights but with similar biological

activity. The larger fragments primarilyinteract with antithrombin III to inhibitthrombin.

The low molecular weight fragments exerttheir anticoagulant effect by inhibiting theactivity of activated factor X. The

hemorrhagic complications attributed toheparin are thought to arise from the largerhigher molecular weight fragments.



The optimal regimen for the treatment of DVT is anticoagulation with heparin or an

LMWH followed by full anticoagulation withoral warfarin for 3-6 months Warfarin therapy is overlapped with heparin

for 4-5 days until the INR is therapeutically

elevated to between 2-3.



After an initial bolus of 80 U/kg, a constantmaintenance infusion of 18 U/kg is initiated.

The aPTT is checked 6 hours after the bolusand adjusted accordingly. . The aPTT is repeated every 6 hours until 2

successive aPTTs are therapeutic. Thereafter,

the aPTT is monitored every 24 hours as wellas the hematocrit and platelet count.



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, Enoxaparin,

Dalteparin, and Ardeparin



Interferes with hepatic synthesis of vitaminK-dependent coagulation factors

Dose must be individualized and adjusted tomaintain INR between 2-3 2-10 mg/d PO caution in active tuberculosis or diabetes;

patients with protein C or S deficiency are atrisk of developing skin necrosis



Advantages include prompt resolution of symptoms,

prevention of pulmonary embolism, restoration of normal venous circulation, preservation of venous valvular function, and prevention of postphlebitic syndrome.



Thrombolytic therapy does not prevent clot propagation,

rethrombosis, or subsequent embolization. Heparin therapy and oral anticoagulant

therapy always must follow a course of

thrombolysis.



Thrombolytic therapy is also not effective once the

thrombus is adherent and begins to organize The hemorrhagic complications of thrombolytic

therapy are formidable (about 3 times higher),

including the small but potentially fatal risk of intracerebral hemorrhage.



indications when anticoagulant therapy is ineffective

unsafe, contraindicated. The major surgical procedures for DVT are

clot removal and partial interruption of the

inferior vena cava to prevent pulmonaryembolism.



These pulmonary emboli removed at autopsy look

like casts of the deep veins of the leg where theyoriginated.





Indications for insertion of an inferior venacava filter

Pulmonary embolism with contraindicationto anticoagulation Recurrent pulmonary embolism despite

adequate anticoagulation



Controversial indications: Deep vein thrombosis with contraindication

to anticoagulation Deep vein thrombosis in patients with pre-

existing pulmonary hypertension Free floating thrombus in proximal vein

Failure of existing filter device Post pulmonary embolectomy



Inferior vena cava filters reduce the rate of pulmonary embolism but have no effect on

the other complications of deep veinthrombosis. Thrombolysis should beconsidered in patients with major proximalvein thrombosis and threatened venous

infarction

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Most patients with confirmed proximal vein DVTmay be treated safely on an outpatient basis.Exclusion criteria for outpatient management are as

follows: Suspected or proven concomitant pulmonary

embolism Significant cardiovascular or pulmonary

comorbidity Morbid obesity Renal failure

Unavailable or unable to arrange close follow-up

Patients are treated with a low molecular weight






















Patients are treated with a low molecular weightheparin and instructed to initiate therapy withwarfarin 5 mg PO the next day. Low molecular

weight heparin and warfarin are overlapped forabout 5 days until the international normalizedratio (INR) is therapeutic.

If inpatient treatment is necessary, low molecularweight heparin is effective and obviates the needfor IV infusions or serial monitoring of the PTT.

With the introduction of low molecular weightheparin, selected patients qualify for outpatienttreatment only if adequate home care and closemedical follow-up care can be arranged.

Platelets also should be monitored and heparin




















Platelets also should be monitored and heparindiscontinued if platelets fall below 75,000.

While on warfarin, the prothrombin time (PT) must

be monitored daily until target achieved, thenweekly for several weeks. When the patient isstable, monitor monthly.

Significant bleeding (ie, hematemesis, hematuria,gastrointestinal hemorrhage) should beinvestigated thoroughly since anticoagulant

therapy may unmask a preexisting disease (eg,cancer, peptic ulcer disease, arteriovenousmalformation).

















Transient cause and no other risk factors: 3 months Idiopathic: 3-6 months Ongoing risk for example, malignancy: 6 -12 months Recurrent pulmonary embolism or deep vein

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

exceeding risk of anticoagulation: indefiniteduration (subject to review)
















Patients with suspected or diagnosedisolated calf vein DVT may be dischargedsafely on a nonsteroidal anti-inflammatory

drug (NSAID) or aspirin with close follow-upcare and repeat diagnostic studies in 3-7 daysto detect proximal extension.

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














Patients with suspected DVT but negativenoninvasive studies need to be reassessed bytheir primary care provider within 3-7 days.

Patients with ongoing risk factors may needto be restudied at that time to detectproximal extension because of the limited

accuracy of noninvasive tests for calf veinDVT.













Acute pulmonary embolism Hemorrhagic complications Chronic venous insufficiency









All patients with proximal vein DVT are at

long-term risk of developing chronic venousinsufficiency.

About 20% of untreated proximal (above thecalf) DVTs progress to pulmonary emboli,and 10-20% of these are fatal. Withaggressive anticoagulant therapy, the

mortality is decreased 5- to 10-fold. DVT confined to the calf virtually never

causes clinically significant emboli and thusdoes not require anticoagulation


















Advise women taking estrogen of the risks

and common symptoms of thromboembolicdisease.

Discourage prolonged immobility,particularly on plane rides and long car trips











Ideidentify any patiant who is at risk. Prevent dehydration. During operation avoid prolonged calf compression. Passive leg exercises should be encourged whilst

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

return.

Early mobilization should be rule for all surgicalpatients.




















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