Anticoagulation and antiplatelet therapy

Question 1

Unfractionated Heparin action is monitored by:

Answer 1

aPTT, activated partial thromboplastin time. target 30-50s. Measures intrinsic and common pathway

(partial, excluding TF, including an activator-cilica)

Question 2

thromboplastin

Answer 2

phospholipids calcium, and Tissue factor.

Question 3

Partial thromboplastin

Answer 3

phospholipids and calcium

Question 4

LMWH difference from Unfractionated heparin

Answer 4

Still binds AT3, but only inhibits factor Xa and doesnt inhibit thrombin directly.

Its effect is not reliably measured by aPTT.

Question 5

When is heparin used?

Answer 5

In acute anticoagulation, PCI, onset of warfarin, bridging.

Also during pregnancy, it doesn’t cross placenta

Question 6

What are the direct thrombin inhibitors

Answer 6

DABIGATRAN -oral

Bivalirudin - IV during PCI.

Question 7

What are the direct factor Xa inhibitors

Answer 7

(The ones that have XA in their names)

Apixaban

Rivaroxaban

Question 8

What does warfarin inhibit

What factors does it decrease activity for

Answer 8

Vitamin K Epoxide Reductase

Thrombin, factors 7, 9, and 10

Question 9

What test is used to monitor warfarin effect

When is it contraindicated

Answer 9

INR, prothrombin test, (uses factor 7, measures extrinsit and common pathway.

Contra’d in pregnancy

Question 10

What test determines anticoagulation treatment

Answer 10

CHA2DS2=VASC

1 point - warfarin or aspirin
more than 1 point - warfarin

Question 11

Thrombolytics and the mechanism of action

Answer 11

tPA. activates plasminogen to plasmin, but only has activity when the plasminogen is bound to a fibrin clot.

Streptokinase. activates plasminogen independently of fibrin.

Question 12

Antiplatelet drugs

Answer 12

Aspirin, irreversibly inhibits COX enzymes, decreases TXA2 levels and platelet activation.

gp2b3a inhibitors, abciximab.

Clopidogrel, Prasugrel

Inhibit ADP receptor on platelets

Dipyridamole - PDE inhibitor, elevating cAMP and cGMP. causes platelet inhibition and some vasodilation.

Question 13

What class is Dipyridamole

Answer 13

Phosphodiesterase inhibitor.

Question 14

Important Statin side effects

Answer 14

Elevated liver enzymes, need to be monitored at 3, 6, and 12 months, then once per year.

If they increase by 3 times the baseline drugs need to be stopped, and the damage is reversible.