Anticoags ppt

Presented by,

Dr Saqba Alam

J of IMAB. 2013, vol. 19, issue 4

The aim of oral anticoagulant therapy is

to reduce blood coagulability to an

optimal therapeutic range within which

the patient is provided some degree of

protection from thromboembolic events.

This is achieved at the cost of a minor risk

of haemorrhage.

Oral anticoagulant therapy is prescribed for :

prophylaxis and treatment of pulmonary embolism

venous thromboembolism

deep vein thrombosis, DVT

For the prevention of postoperative venous thromboembolism after orthopaedic surgical procedures as hip fracture and prosthetic total hip or knee joint replacement,thromboembolic complications associated with atrial fibrillation and/or prosthetic replacement of cardiac valves.

INDIRECT ACTING ANTICOAGS (Coumarin derivatives)

Acenocoumarol - derivative of coumarin

MOA vitamin K antagonist

Peak of action with oral intake occurs 12 h

after administration. After discontinuation, the action persists for 48 - 72 h.

Atrial fibrillation and mitral stenosis

history of embolism

age over 65

hypertension; diabetes or expressed left ventricular hypertrophy

intramural thrombus of the heart after a infarction or aneurysm (3-6 months)

artificial heart valves, with a limited left ventricular function

Coumarin derivative

MOA : Acts on extrinsic clotting pathway by preventing the reduction of vitamin K into its active form.

Depending on the reason for the anticoagulation (cardiovascular thrombo-embolic risk), the patient’s target INR therapeutic ranges will be different.

Patients with atrial fibrillation, DVT, or stroke have a target INR of 2.0 to 3.0, whereas after undergoing cardiac valve replacement surgery, patients have a target range of 2.5 to3.5.

Patients taking warfarin may require bridging anticoagulation around the time of major surgery.

This involves replacing the warfarin with unfractionated or low molecular weight heparin. Consultation with a cardiologist is particularly recommended if a patient with a coronary stent requires surgery.

Bridging anticoagulation refers to giving a short-acting blood thinner, usually low-molecular-weight heparin given by subcutaneous injection for 10 to 12 days around the time of the surgery/procedure, when warfarin is interrupted and its anticoagulant effect is outside a therapeutic range.

Bridging anticoagulation aims to reduce patients' risk for developing blood clots, such as stroke, but may also increase patients' risk for developing potentially serious bleeding complications after surgery.

Dabigatran is a selective, reversible

direct thrombin inhibitor currently used in Europe and North America for stroke prevention in nonvalvular AF and in Europe for VTE prophylaxis in orthopedic patients.

Rapid onset of action.

It is able to provide stable anticoagulation at a fixed dose without the need for routine laboratory monitoring of INR and associated dosage adjustments.

No specific antidote or reversal agent exists.

However, owing to dabigatran’s short half-life (12-14 hours (14-17 hours in the elderly)), merely discontinuing the administration of the drug is thought to be sufficient to resolve minor bleeding in most circumstances.

Rivaroxaban is approved in Europe and North America as a highly selective Direct Factor Xa a Inhibitor.

MOA- Rivaroxaban interrupts the intrinsic and extrinsic pathway of the blood coagulation cascade, inhibiting both thrombin formation and development of thrombi. Rivaroxaban does not inhibit thrombin and no effects on platelets have been demonstrated.

It also provides stable anticoagulation at a fixed dose without the need for routine INR monitoring.

There is no specific reversal agent or antidote for rivaroxaban, but its short half-life means that the discontinuation of the drug is likely be adequate to correct most bleeding problems caused by its use.

Tests for anticoagulation assessment

The prothrombin time ratio (PTR), defined as the patient’s prothrombin time (PT) was used to monitor anticoagulant therapy for many years.

INR as an (ISI )index.

PT INR ratio INR =(PT test/PT normal)ISI

BY ( the International Committee on Thrombosis and Homeostasis 1985)

It is now widely used for monitoring anticoagulant therapy and dosage planning. The INR for a healthy patient is 1 and the therapeutic INR for those on anticoagulant therapy typically ranges from 2 to 4, depending on the reason for anticoagulation.

BCSH (British Committee for Standards in Haematology), the British Society for Haematology Committee, the British Dental Association (BDA), the National Patient Safety Agency (NPSA) presented a guideline in after reviewing in the year 2011, whose summary was…….

In pts with INR <4 (LOW) no need to discontinue oral

anticoags as the risk of thrombosis is increased.

GRADE A (LEVEL IB)

For patients stably anticoagulated on warfarin (INR

2-4) and who are prescribed a single dose of

antibiotics as prophylaxis against endocarditis,

there is no necessity to alter their anticoagulant

(grade C, level IV).

For patients who are stably anticoagulated on

warfarin, a check INR is recommended 72 hours

prior to dental surgery.

PTS with co-existing medical problems e.g. liver

disease, renal disease, thrombocytopenia .Such

patients may have an increased risk of bleeding.

NONE of these approaches is risk free

for the pt and the surgeon must make

a clinical judgement of the risk benefit

ratio between management

strategies and adverse complications.

Wahl reviewed 26 papers comprising 2014

dental surgical procedures in 774 patients

receiving continuous warfarin therapy,

THE CONCLUSION WAS….

Twelve patients (<2%) had postoperative

bleeding problems that were not controlled

by local measures

Major bleeding was rare (4/2012, 0.2%) for

patients with a therapeutic INR (<4)

undergoing dental surgery.THERE WERE NO

DEATHS……

The risk for FATAL pulmonary embolism

after discontinuing anticoagulant

therapy is 0.19 to 0.49 events per 100

person years for patients undergoing

anticoagulant therapy.

The case fatality rate from recurrent PE is

4% TO 9%

Specific consideration must be

given to the issue of whether oral

anticoagulant treatment should

be unaltered,modified, or

stopped according to possible

bleeding complications.

Hong C. et al. reported a study with 122

patients who had a total of 240 dental

extractions. 35 patients (29%) were on

concomitant medications thought to

potentate bleeding.7 patients were on

multiple antithrombotic

medications(excluding warfarin); 2 were

taking a combination of aspirin,cilastazol,

and nonsteroidal analgesic medication; 3

were on a combination of aspirin and

clopidogrel; and 2 were on acombination

of aspirin and enoxaparin.

The results of this retrospective study

suggest that the overall prevalence of

persistent bleeding after dental

procedures in patients on warfarin

therapy is low (2%).

Additionally, most complications

experienced were controlled with local

hemostatic measures

INR values should be obtained within 24 hours before the dental procedure. For patients with INR in the therapeutic range 2-4 or below, therapy need not be modified or discontinued for simple single dental extractions. More complicated and invasive oral surgical procedures for patients with an INR on the high end of the scale or greater than 3.5 should be referred to physician for dose adjust mentor therapy alteration before invasive dental procedures

(Ref : OCT 24,2003 GRACE REGISTRY EUR.HEART.J)

Local hemostatic measures are shown to

suffice to control the possible bleeding

secondary to dental treatments.

The risk of bleeding may be minimized by:

a.Pressure and Packing !!!....

b.The use of oxidized cellulose (Surgical) or collagen sponges and

c.sutures (grade B, level IIb).

d. 5% tranexamic acid mouthwashes used four times a day for 2 days (grade A, level Ib).

Ref : (Sept 2011Guidelines for the management of patients on oral anticoagulants requiring dental surgery

British Committee for Standards in Haematology)

.

BLEEDING

VS

THROMBOSIS

It is necessary to carefully evaluate the

bleeding risk of the planned

treatment, as well as the thrombotic

risk of suppressing the anticoagulant

or antiplatelet medication, on an

individualized basis for each patient,

with a view to providing optimum and

personalized care.

THANK YOU !!