Present by: Maryam AL-Qahtani

Week3

Introduction

Is when one or more pulmonary arteries in lungs become blocked.

Caused by blood clots that TRAVEL to the lungs from the legs or rarely other parts of the body (deep vein thrombosis).

Pulmonary embolism

Objectiv

es: What are the specific investigation to be done for a PE patient ?

What are the anticoagulation agent which can be given in pulmonary embolism as a prophylactic or therapeutic ?

What are the different types of heparin ?

What are the

specific

investigation to be

done for a PE

patient ?

The choice and order of investigations will depend on

The clinical likelihood of PE.

How ill the patient is (stable or unstable).

Availability of the test.

D-dimer test

Degradation product of cross-linked fibrin.

Elevated in plasma in the presence of clot

because of the activation of coagulation and

fibrinolysis.

A sensitivity of >95% and effectively

excludes PE.

Qualitative d-dimer tests are less reliable, but

they have been used safely in the primary care

setting with the wells rule in excluding PE.

The specific investigation :Computed tomographic pulmonary

angiography.

Isotope lung scanning (V/Q scan;Ventilation-

perfusion lung scintigraphy).

Leg ultrasound.

Computed tomographic pulmonary

angiography.

CTPA has become the method of choice for imaging the pulmonary vasculature in patients with suspected PE

Why ?

Its wider availability

Ability to demonstrate alternative causes of symptoms.

Fast and generally well tolerated

Has superior sensitivity for the detection of small

subsegmental emboli (detects clots in smaller vessels.)

Isotope lung scanning (V/Q scan)

to evaluate the circulation of air and blood within a patient's lungs, in order to determine the

ventilation/perfusion ratio.

The ventilation part of the test looks at the ability of air to reach all parts of the lungs-while the perfusion part evaluates how well blood circulates within the lungs.

A ventilation/perfusion lung scan(a V/Q lung scan)

VQ or CTPA?

Both accurateCTPA :widespread availability VQ scanning: may not be available outside working hours. Radiation dose of VQ is significantly less than CTPA, which makes VQ preferable for young women.There is a higher risk of contrast-induced nephropathy with intravenous contrast for CTPA in patients with moderate-to-severe renal impairment and VQ is preferable in these patients.

Leg ultrasound

Why ?

High sensitivity for detection of proximal deep vein thrombosis

(DVT), which is the source of PE in 90% of patients.

A positive lower limb us is present in 30–50% of patients with

PE.

Useful where tests using ionising radiation are less desirable,

for example in pregnancy.

What are the anticoagulation agent

which can be given in pulmonary

embolism as a prophylactic or

therapeutic ?

An

tico

agu

lati

on

Anticoagulants work by increasing the

time it takes a blood clot to form. They

also prevent a clot from getting bigger.

Immediate therapeutic anticoagulation

should be initiated for patients in whom

DVT or pulmonary embolism (PE)

Anticoagulation therapy reduces

mortality rates from 30% to less than

10%

Prophylactic anticoagulation agents:

• Most hospitalized patients developed VTE.

• The estimated risk factor is high as 50% when thromboporphylaxis is not used.

Prophylaxis measurements

• Early mobilization.• Elevation of the legs.• Compression stocking.• Intermittent compression device.• Use of drug such as : LMWH , and Anti-thrombin.

Therapeutics anticoagulation agents:

Aim of Treatment:

prevent further thrombosis and PE while resolution of venous thrombi occur by natural fibrinolytic activity.

1. Start w. : Heparin as its produced direct effect, For 5 Days

2. LMWH e.g. (Tinzaparine 175 U/kg daily, Delteparin 200 U/kg daily,

Enoxaprain 1.5 mg/kg daily) is effective and safe for immediate treatment as

unfractionated heparin.

3. At the follow up : For Long –term medication will use warfarin to maintain a

target INR of 2.0-3.0

• 6 weeks for isolated calf vein thrombosis.

• 3 months after participated proximal DVT or PE in

patient with temporary risk factors.

• 3 to 6 months in idiopathic VTE or permanent risk

factors.

Length of Anti-Coagulation

Outpatient

• Best to be supervised in anticoagulant clinics.

• IVC filters are an important tool to prevent PE in patients that have a contraindication to anticoagulation.

Summary :

• Start the therapy by Heparin or low molecular

weight heparin (LMWH) followed by …

• 6 months Warfarin with an international normal

ratio of 2 to 3.

What are the

different types

of heparin ?

Heparin

An anticoagulant or a medication that prevents clots from forming

Attaches to antithrombin III

Antithrombin III is a protein that breaks up substances that will

form a clot.

With heparin attached to it, antithrombin III is 1,000 times more

effective

Types of heparin

Heparin (standard Unfractionated)

Low-Molecular-Weight Heparins

Heparin (standard Unfractionated)

• Mixture of polysaccharides.

• Consist of components with molecular weight varying from 5000-35000.

• Inactivates several coagulation enzymes, including Factors IIa(thrombin), Xa, IXa, XIa, and XIIa.

Low-Molecular-Weight Heparins

• Producing fractions with molecular weight in the range of 2000-8000.

• It has greater activity against factor Xa than against factor IIa.

Mechanism

Differenc

esBioavailability:

LMWH is better than that of unfractionated heparin.

Activity against factor: Inactivates several coagulation enzymes while LMWH greater activity against factor Xa than against factor IIa, suggesting that they may produce an equivalent anticoagulant effect to standard heparin.

Side effect:LMWH have a lower risk of bleeding and less inhibition of platelet function.

half-life:LMWH have a longer half-life than standard heparin andso can be given as a once-daily subcutaneous injectioninstead of every 8–12 h.

Fondaparinux

• Inhibits activate factor X, similar to the LMW heparins.

• Binds to AT with a higher affinity

• Cannot bind to and inactivate thrombin (factor IIa)

• Not expected to induce thrombocytopenia

• 100 percent bioavailable after subcutaneous injection

• The half-life of this agent is much longer (15 to 17 hours)

Side effect• >10%Heparin-induced thrombocytopenia, possibly delayed (10-30% )

Frequency Not Defined• Mild pain• Hematoma

• Hemorrhage• Local irritation• Erythema• Injection site ulcer (after deep SC injection)• Increased liver aminotransferase• Anaphylaxis• Immune hypersensitivity reaction• Osteoporosis (long-term, high-dose use)

Physicians decide which type of

heparin to use based upon:

Effectiveness

Safety

Cost.

Merck Manual.

.Up to data.website

Kumar and Clark book http://atvb.ahajournals.org/content/21/7/1094.long http://www.livestrong.com/article/252722-types-of-

heparin/ http://www.thrombosisadviser.com/en/vte-

prevention/heparins/ http://emedicine.medscape.com/article/300901-treatment http://reference.medscape.com/drug/calciparine-

monoparin-heparin-342169#4

References