DEEP VEIN DEEP VEIN THROMBOSISTHROMBOSIS

Prepared by : Maria Devi Adlin

Supervisor : Dr Hasmali

OUTLINEOUTLINE Definition Epidemiology Anatomy Pathophysiology Risk factor Approach to DVT Management complication Prevention Take home message

DefinitionDefinitionDeep venous thrombosis (DVT) is

a formation of blood clots or thrombus in the deep vein of legs or pelvic.

Anatomy of deep Anatomy of deep veinsveins

In the lower leg, three pairs of deep veins exist:

anterior tibial vein (ATV), draining the dorsum of the foot;

posterior tibial vein (PTV), draining the medial aspect of the foot;

the peroneal vein, draining the lateral aspect of the foot.

Just below the knee, all the deep veins joint to become the single large popliteal vein.

In the proximal thigh, the FV and the DFV join together to form the common femoral vein (CFV), which passes upward and form the iliac vein.

Superficial Vein :Superficial Vein :The Great Saphenous Vein originates from

the dorsal venous arch of the foot.After passing anterior to the 

medial malleolus, it runs up the medial side of the leg.

At the knee, it runs over the posterior border of the medial epicondyle of the femur bone.

The great saphenous vein then courses medially to lie on the anterior surface of the thigh before entering the saphenous opening.

It joins with the femoral vein in the region of the femoral triangle at the saphenofemoral junction.

AetiologyAetiology

Virchow’s triad:

a) Endothelial injuryb) Stasis or turbulence of blood flowc) Hypercoagulability of the blood

ENDOTHELIAL INJURY

Reduced or stagnant blood flow HYPERCOAGULABILITY

THROMBOSIS

Virchow’s triadVirchow’s triad

In extremely sluggish flow ,thrombus formationin the vein valve pockets is. Thrombus formation occurswhen the natural antithrombotic mechanisms are overcome.By production of• prostacyclin, nitric oxide and tissue plasminogen activator• cell-surface glycosaminoglycans (e.g. heparin sulphate)• the physiological inhibitors of clotting (e.g. antithrombin,proteinC, protein S, see below).

Endothelial damage (due to directtrauma and/or damage to endothelial cells by hypoxia causedby stasis) in the presence of activated clotting factors initiatesthrombosis

there are four main anticoagulant mechanismsin the coagulation cascade that maintain blood flow and restrict thrombosis only to site of injury:• antithrombin• protein C and protein S• tissue factor pathway inhibitor• the fibrinolytic system

Risk FactorsRisk FactorsSTASIS/ENDOTHELIAL INJURY

THROMBOPHILIA MEDICAL CONDITION

DRUGS OTHER

Indwelling venous device

Surgery (most common pelvic and orthopedic)

Major trauma, fracture

Prolonged travel

Paralysis (including anaesthesia > 30 min)

Varicose vein

Activated protein C resistance

Prothrombin gene mutation

Factor V Leiden

Dysfibrinogenemia

Dysplasminogenemia

Hyperhomocysteinemia

Anticardiolipin antibodies

Lupus anticoagulant

Elevated factor VIII level

Protein C deficiency

Protein S deficiency

Malignancy (solid tumor & myeloproliferative disorder)

Pregnancy

MI

CHF

Stroke

Obesity

IBD

Nephrotic syndrome

History of DVT

Heparin-induced thrombocytopenia

Paroxysmal nocturnal hemoglobinuria

Oral contraceptive use

Hormone replacement therapy

Chemotherapy (inclding Tamoxifen)

Increasing age

How to Approach DVTHow to Approach DVT• History

• Presenting complaint – pain, swelling• Time of onset• Is it both legs?• Has there been any trauma?• Is there any pain? (65% below knee DVT are

asyptomatic)• Is there any swelling? How recent?• Have there been any skin changes?• Any odema anywhere else?• Is the patient mobile?• Recent surgery or trauma/fractures• Paralysis/paresis• Plaster immobilisation of lower limb• Recently bedridden for >3 days or major surgery

<4 weeks.

• Look for Symptoms of PE– Pleuritic, sharp chest pain– Acute onset of breathlessness– Haemoptysis

• Previous Medical History– DVT or PE. Arthritis. Malignancy (ongoing treatment, within 6 months or

palliative)– Thrombophilia. Recurrent miscarriages. Diabetes. MI. AF. CVA

• Family History– DVT or PE. Cardiac problems. CVA. Clotting disorders

• Risk Factors– Age, smoker, pregnancy, long haul travel, obesity, immobility

• Drug history & Allergies– Immunosuppressant drugs. Contraceptive pill. Warfarin. IV drug user

Clinical featuresClinical featureshalf of all DVT cases do not cause

symptoms depend on the location and size

swellingrednessTendernessmuscle indurationMild pyrexia

Homan’s sign - tenderness during passive dorsiflexion of foot.

Pratt’s sign - Squeezing of posterior calf elicits pain

Phlegmasia alba dolens - pale, pulseless cold limb due to concurrent arterial spasm

Phlegmasia caerulea dolens - cyanosed limb due to obstructed vein

Clinical PresentationClinical Presentation

Phlegmasia alba dolens Phlegmasia caerulea dolens

DiagnosisDiagnosis• InvestigationsInvestigations

»Complete blood count – Hb, PCV, Platlet count and White cell count»Primary coagulation study»Liver enzymes»Renal function and electrolytes»D – Dimer – fibrin degradation product) is increasingly being used as a screening adjunct. It has a sensitivity of >90% and a specificity of 30–40%.»ECG

• ImagingImaging– Chest radiograph– B-mode ultrasound

–is the first-line non-invasive investigation–a non-compressible thrombus in the thigh and popliteal veins can be diagnosed with 97% sensitivity and 94% specificity

– Venography–invasive, uncomfortable and requires injection of contrast.

– Spiral CT and CT pulmonary angiography –investigations to diagnose pulmonary embolism.

Well’s CriteriaWell’s CriteriaClinical feature PointsActive cancer (treatment within 6 months, or palliation)

1

Paralysis, paresis, or immobilization of lower extremity

1

Bedridden for more than 3 days because of surgery (within 4 weeks)

1

Localized tenderness along distribution of deep veins

1

Entire leg swollen  1Unilateral calf swelling of greater than 3 cm (below tibial tuberosity)

1

Unilateral pitting edema 1Collateral superficial veins 1Alternative diagnosis as likely as or more likely than DVT

-2

Total points  

Wells Clinical Prediction Rule for Deep Venous Thrombosis (DVT) Risk score interpretation (probability of DVT): •>/=3 points: high risk (75%); •1 to 2 points: moderate risk (17%);•<1 point: low risk (3%).

• not universally used, still debatable

ComplicationsComplications• Pulmonary Embolism

»The clot from lower limb become detached & passes via IVC & right heart to the pulmonary arteries and may totally occlude the perfusion to part or all of one or both lungs

• Post-thrombotic Limb»Valves in the deep venous channels of the

lower leg have been damaged by thrombotic process

» Recanalized deep veins are functionally inadequate because of the damaged valve.

» bidirectional flow & abnormally high ambulatory venous pressure in the deep vein→ transmitted to subcutaneous vein→ edema, pigmentation, edema, pigmentation, fibrosis, and later, dermatitis, cellulitis fibrosis, and later, dermatitis, cellulitis and ulcerationand ulceration

TAKE HOME MESSAGES :TAKE HOME MESSAGES : DVT is one of those things that has a number of predisposing

causes, so it is in fact mostly preventable Clinical predictive rule : Well’s criteria