Page 594 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

578 PART 7 ■ Principles and Disorders of Hemostasis and Thrombosis

■ A e ciency o actor IX is known as he o hi ia B or ■ Acquire inhibitors o c otting roteins, a so known as
Christ as isease. circu ating anticoagu ants, inactivate or inhibit the usua

■ A e ciency o actor XI is re erre to as he o hi ia C. rocoagu ant activity o coagu ation actors.

■ Fibrinogen e ciency as a genetic isor er ay re resent ■ S eci c inhibitors against actors II, V, VII, VIII, IX, XII,
a e ect o ro uction or ys unctiona o ecu es. an XIII an vWF have been etecte in atients with

■ Here itary e ciencies o the other coagu ation actors are in ivi ua actor e ciencies.
re ative y rare. ■ So e inhibitors o actors II, V, VII, IX, an XII an vWF

have been observe in atients having no e ciencies o
Disorders of Destruction and Consumption coagu ation actors.

■ B oo coagu ation actors can be estroye in vivo by
enzy atic egra ation or by atho ogica activation o Anticoagulant Therapy

coagu ation with excessive uti ization o the c otting ac-

tors. Enzy atic estruction can resu t ro bites by cer- ■ Most c inica aboratories are accusto e to onitoring

tain s ecies o snakes whose veno contains an enzy e atients who are receiving war arin (Cou a in) or he a-

that egra es brinogen to a e ective brin ono er. rin anticoagu ant thera y

■ In vivo activation o coagu ation by tissue thro bo as- ■ In recent years, new ora anticoagu ants (NOAs) ac-
tin– ike ateria s can ro uce excessive uti ization o tor Xa inhibitor a ixaban (E iquis, P zer an Bristo -

c otting actors. Con itions that can cause this consu - Myers Squibb), thro bin inhibitor abigatran (Pra axa,

tion o coagu ation actors inc u e obstetrica co ica- Boehringer Inge hei )), an actor Xa inhibitor rivaroxa-

tions, trau a, burns, rostatic an e vic surgery, shock, ban (Xare to, Bayer Hea thcare AG an Janssen Research

a vance a ignancy, se tice ia, an intravascu ar & Deve o ent LLC, a Johnson & Johnson Co any),

he o ysis. an actor Xa inhibitor e oxaban have revo utionize

■ Pri ary an secon ary brino ysis are recognize as anticoagu ation thera y.
extre e co ications o a variety o intravascu ar an ■ War arin rugs are vita in K antagonists that inter ere

extravascu ar isor ers an ay have i e-threatening with the nor a synthesis o actors II, VII, IX, an X as

consequences. we as roteins Protein C an Protein S.

■ Pri ary brino ysis is associate with con itions in ■ He arin has no anticoagu ant activity o its own but acts as
which gross activation o the brino ytic echanis with an anticoagu ant by acce erating the bin ing o antithro -

subsequent brinogen an coagu ation actor consu - bin antithro bin to target enzy es (e.g., thro bin an

tion occurs. actor Xa). He arin is ter e an antithro bin antithro -

■ A though the sa e c inica con itions ay a so in uce bin because it he s to revent new thro bus or ation
secon ary brino ysis or DIC, the istinction between the an buys ti e or en ogenous brino ytic echanis s to

two is essentia y in the e onstration o brin or ation. yse the c ot.

In secon ary brino ysis, excessive c otting an brino- ■ Te search to re ace war arin, the anticoagu ant “go

ytic activity occur. stan ar ,” was triggere because o the i cu ty o sta-

bi izing atients in the thera eutic internationa nor a -

ize ratio (INR) range o 2.0- to 3.0. Regu ar onitoring
The Hypercoagulable State (Thrombophilia)
o war arin is require to avoi the risks o both b ee ing

■ An increase in the ike ihoo o b oo to c ot is re erre to ro excee ing the thera eutic range oran un ertreat-

as the hy ercoagu ab e state. ent that ay not a ow the reso ution o a b oo c otting

■ Hy ercoagu ab e states inc u e various inherite an rob e or ay a ow c ots to or

acquire c inica isor ers characterize by an increase ■ War arin has been the on y ora anticoagu ants or the

risk or thro boe bo is . treat ent o venous thro boe bo is or eca es. T e

■ T e ajor inherite inhibitor isease states inc u e anti- ajor i itations o treat ent with war arin areis a nar-

thro bin e ciency, rotein C e ciency, an rotein S row thera eutic win ow, that is, i.e. INR, an the s ow

e ciency. onset o e ects an o set o action.