VTE Prophylaxis by Dr.Hiwa M.Tofeq 13/4/2014

Annual mortality due to VTE in Europe (25 countries)Mortality due to VTE1

in hospital 261,477ambulatory 108,535

Combined mortality due to :AIDS 5,8602

Breast cancer 86,8312

Prostate cancer 63,6362

Traffic accidents 53,5992

209,926

1Cohen AT. Presented at the 5th Annual Congress of the European Federation of Internal Medicine; 2005.2Eurostat statistics on health and safety 2001. Available from: http://epp.eurostat.cec.eu.int

Venous thrombosisVenous thrombosis is the formation of a semi-solid coagulum within the venous circulation, manifests as deep vein thrombosis (DVT) or pulmonary embolism (PE).

Pathologically thrombus formed initially by platelet aggregation, then fibrin …. From clot factors…. Red cell.. Thrombus formation.. Venous lumen occlusion… extend to the large veins.

Three factors described by Virchow

Risk factors*:

* according to the Nice guideline for prevention of VTE

Weak Risk Factors Moderate Risk Factors Strong Risk Factors

• Increasing Age > 60 yr.• Obesity BMI > 30

kg/m2• Bed rest >3 days• Immobility due to sitting• Laparoscopic Surgery• Pregnancy/ Antepartum• Varicose Veins• polycythemia

• Arthroscopic Knee Surgery

• Central Venous Lines• Chemotherapy• CHF or Respiratory

Failure• Hormone Replacement

Therapy• Malignancy• Oral Contraceptive

Therapy• Paralytic Stroke• Pregnancy/ Postpartum• Previous VTE• Thrombophilia• Smoking

• Hip or Leg Fracture• Hip or Knee

Replacement• Major General Surgery• Major Trauma• Spinal Cord Injury

Risks* according to the types of surgical

operation

VTE is more common with GA than with SA..

* Bialy and love short practice

Low risk (10-20%) Medium risk (15-40%) High risk (40-60%)

• Maxillofacial surgery• Neurosurgery• Cardiothoracic surgery

• Inguinal Hernial repair• Urological surgery• Gynecological surgery• Abdominal surgery

• Pelvic surgery .. Both elective and trauma surgery

• Total hip and knee replacement

Clot formation:Most important step is

action of clot factors and formation of fibrin…

Prevention of VTE

Mechanical:

Several methods are available:

Graduated compression stockings: are effective in decreasing the risk of DVT.

contra-indicated (egg in patients with established peripheral arterial disease, massive leg edema or diabetic neuropathy).

Skin destruction and limb ischemia are regarded as complications of GCS.

The stocking compression profile should be equivalent to the Sigel profile (a pressure profile for elastic stockings) and approximately:

18 mm Hg at the ankle

14 mm Hg at the mid-calf

8 mm Hg at the upper thigh

Intermetent pneumatic compression (IPC):

calf length pneumatic compression devices seem to offer the same protection for VTE as LMWH or low dose heparin.

With pneumatic compression devices there is no increased risk of bleeding and therefore little limitation of use.There are no data to support the use of PCDs on only one extremity or the upper extremities during surgery.Contra-indications are (dermatitis, recent skin graft, ischemic vascular disease, severe leg edema, suspected preexisting DVT, and extreme leg deformity)

Complications from pneumatic compression devices include nerve compression leading to neuropathy and rare incidences of allergies to the component materials.

PROPHYLACTIC METHODS: Unfractionated heparin (low dose UH):

The dose is 5000 U given subcutaneously which reduces the risk of venous thrombosis and fatal PE by 60% to 70%. This should be started within two hours of operation and then every 8 or 12 hours, (Every 8 hours is probably more effective at preventing VTE with similar risk of major bleeding). Duration…

It produces its major anticoagulant effect by inactivating thrombin and activated factor X (factor Xa).

Low molecular weight heparin:(LMWH) the dose and frequency for LMWH depends on the manufacturer, and should be used according to their recommendations, although patient weight may also be a factor.

LMWH is at least as effective as low dose UH with a similar risk of major bleeding. There is decreased dosing schedule and decreased risk of heparin induced thrombocytopenia with LMWH compared to UH.

Most polices start dosing the night before surgery with no other preoperative dosing to decrease the risk of operative bleeding.

Special consideration needs to be given when using LMWH with epidural or spinal anesthesia because of the risk of causing hematoma during placement or removal of the catheter.

Complication of heparin:-Type II heparin-induced thrombocytopenia (HIT) is an immune-mediated complication of heparin therapy, which may be associated with significant morbidity and mortality.. HIT can occur with any dosage or type of heparin administered. However, the incidence of HIT increases with higher dosages and longer duration of therapy, and with the use of unfractionated heparin versus low molecular weight heparin (LMWH).

-Hemorrhage…. Adrenal hemorrhage, Ovarian and Retroperitoneal hemorrhage..

Contra-indication:

. Active bleeding, egg intracranial bleeding.

. High risks of bleeding (hemophilia, thrombocytopenia)

. History of upper GI bleeding.

. Severe hepatic failure (INR > 1.3)

. Allergy to heparin

IVC filters: These have been used for high risk

patients. Patients with venous stasis disease, BMI>59, and hypoventilation syndrome or sleep apnea undergoing surgical procedures which classified as a high risk for VTE. Duration.. Follow up..

Study point:

- VTE is killer inside the hospitals.

- VTE is a preventable catastrophe.

- Each hospital should have VTE prophylaxis policy.

- IPC nearly has similar efficacy in prevention of VTE like heparin.

- GA increase the risk of VTE by 5 folds, in comparing with SA.

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References:

Baily and Love’s Short Practice of Surgery.. 26th Edition

NICE guideline for reducing the risk of venous thrombosis.. 2012

Australia guideline for prevention of venous thrombosis .. 4th Edition

Thank You