Coagulation Disorders Flashcards
Hereditary deficiencies include
Hemophilia A
Hemophilia B
Von Willebrand disease
Acquired coagulation deficiencies include
vitamin K deficiency- antibiotics, intestinal malabsorption, impaired nutrition
liver disease- parenchymal disease
disseminated intravascular coagulation
autoantibodies
Treatment of a single-factor deficiency depends on
the severity of the deficiency
For surgical purposes, individual clotting factor levels of
20-25% provide adequate hemostasis
List the products available to treat single deficiencies.
factor concentrates
recombinant factors
gene therapy
FFP- 15-20 mL/kg of FFP is needed to obtain a 20% to 30% increase in the level of any clotting factor
Duration of effect for replacement therapy depends on
the turnover time of each factor
Hemophilia A is a result of
Factor VIII gene deficiency
very large gene on the X chromosome
affects 1 in 5,000 males- can be inherited or gene mutation
Severe hemophilia is the
inversion or deletion of major portions of the Factor VIII gene
Clinical severity of hemophilia A is best correlated with the
factor VIII activity level
Describe severe hemophilia A.
<1% factor VIII activity
- diagnosed in childhood- spontaneous hemorrhage into joints, muscles, and vital organs
- requires factor VIII concentrates
Describe mild hemophilia A.
6-30% factor VIII activity- may go undiagnosed until adulthood & they undergo major surgery
Diagnosis of hemophilia A is through
prolonged aPTT, specific factor testing, and gene testing
Anesthetic considerations for the patient with Hemophilia A include
HEMATOLOGY CONSULT
factor VIII level should be brought to at least >50% prior to surgery
mild hemophilia A- DDAVP 30-90 minutes prior to surgery
Moderate to severe hemophilia A- Factor VIII concentrate
FFP & cryo
Consider TXA as an adjunct
Factor VIII concentrate half-life is
approximately 12 hours in adults (short as 6 hours in children)
may require replacement therapy for days to weeks after surgery
Describe hemophilia B
similar clinical picture as hemophilia A
-1:30,000 males (also X-linked & less common)
How is hemophilia B diagnosed?
prolonged aPTT, specific factor testing, and gene testing
Describe mild vs. severe hemophilia B.
Factor IX levels below 1% are associated with severe bleeding
-mild disease (levels between 5-40%) often not detected until surgery or dental procedure
Describe the anesthesia implications for hemophilia B
similar to hemophilia A HEMATOLOGY consult Replacement therapy- recombinant F-IX, purified F-IX, prothrombin complex concentrate contain II, VII, IX, and X, increased risk of thrombotic events- especially in orthopedic surgery -continue replacement therapy Consider tranexamic acid as adjunct
Describe the different anesthesia implications for hemophilia A versus hemophilia B
With continuance of replacement therapy, factor IX half-life is 18-24 hours so not dosed as frequently
absorbed into collagen & vasculature
The most common congenital bleeding disorder in the world is
Von Willebrand’s disease
- more prevalent in person of European descent
Von Willebrand disease is
a family of disorders caused by quantitative and/or qualitative defect
Von Willebrand factor mediates
platelet adhesion and prolong factor VIII’s half-life
Von Willebrand is synthesized and stored in
endothelial cells & platelets
Describe the action of Von Willebrand.
dual role in hemostasis affecting both platelet function & coagulation
- platelet adhesion- vascular site of injury to PLT’s GIb receptor
- platelet aggregation- PLT GIIb/IIIa receptor to PLT GIIB/IIIa receptor
- Carrier molecule for factor VIII and cofactor for factor IX
Describe type 1 of Von Willebrand disease
most common 60-70% of patients-
mild-moderate REDUCTION in level of vWF
mild bleeding symptoms- easing bruising, nosebleeds
Describe type 2 of Von Willebrand disease
9-30% of patients
QUALITATIVE DEFECT OF VWF
4 subtypes
Describe type 3 of Von Willebrand disease
<1% of patients
nearly undetectable, severe quantitative phenotype
Describe platelet pseudo type Von WIllebrand disease
defect in the platelet’s GIb receptor
What determines the approach to treatment in Von Willebrand’s disease?
the specific type of von Willebrand disease & the location and severity of bleeding
Describe the replacement therapy goals in von Willebrand disease.
Major surgery- maintain factor VIII level >50% for 1 week
minor surgery- maintain factor VIII level >50% for 1-3 days
Dental extraction- single infusion to achieve factor VIII level >50%, desmopressin prior to procedure for type I
spontaneous or posttraumatic bleeding- usually single infusion of 20-40 units/kg
Describe the difference in treatment for factor VIII & IX deficiency
FFP, factor concentrates, & cryo
FFP PCC, factor concentrates
cryo only works for factor VIII
In normal hemostasis, thrombin stays at
the site of vascular injury
In DIC, thrombin is
generated in response to an insulting factor
Insulting factors for DIC can be
endotoxins in sepsis or amniotic fluid embolism
In DIC, the generation of thrombin leads to
intravascular clotting which then disseminates through the body causing end-organ dysfunction
coagulation factors depleted ad platelets are used up or become dysfunctional
fibrinolysis is also activated and results in bleeding
Describe the symptoms of DIC
related to widespread clot formation
-chest pain, SOB, leg pain, problems speaking or moving
patients may present with either clotting or bleeding or both
With DIC hemorrhages occur simultaneously from distant sites
where there is ongoing thrombosis in the microcirculation
-IV sites, catheters, & drains
Causes of DIC include
sepsis- bacterial, viral, fungal surgery trauma cancer- more chronic, insidious onset, often leukemias pregnancy complications- amniotic fluid embolism, HELLP syndrome snake bites- venom frostbite burns transfusion reaction
acute DIC is when the processes of
coagulation & fibrinolysis are dysregulated
Acute DIC causes
widespread clotting with resultant bleeding
- fibrin deposits as thrombosis in the circulation
- depletion of platelets & clotting factors
Regardless of the triggering event of DIC, once initiated, the pathophysiology of DIC
is similar in all conditions
With acute DIC, tissue factor
may be present in many cell surfaces (endothelial, macrophages, monocytes) and tissues (lung, brain, placenta)
tissue factor is exposed & released
binds with FVIIa and activates IX and X to form thrombin and fibrin in the common final pathway
Fibrinolysis creates fibrin degradation products that
inhibit platelet aggregation
have antithrombin activity
impair fibrin polymerization
all of these contribute to bleeding
The paradoxical effect is when
coagulation inhibitors are also consumed
decreased inhibitor levels will permit more clotting
increased clotting leads to more clotting
thrombocytopenia occurs due to platelet consumption
dysfunctional platelets occur due to inflammatory processes
Blood tests in DIC include
DIC panel- these labs in isolation are not helpful
-low platelets (93% of cases)- but also platelet dysfunction
-low fibrinogen
- high INR & PT
-high PTT
-high D-dimer (FDP) (Variable)
TEGs & ROTEMs
Excess thrombin in DIC results in
lots and lots of clotting
- -> depletion of platelets and clotting factors
- -> fibrin degradation products (FDP)
Excess and unregulated thrombin generation causes
consumption of coagulation factors and increased fibrinolysis which in conjunction with platelet dysfunction can lead to bleeding
Consumption of anticoagulant proteins with high antifibrinolytic activity and platelet aggregation also induced by thrombin can lead to
thrombotic complications
Summarize the role of excess thrombin in DIC.
increased coagulation consumption–> bleeding
increased fibrinolysis
decreased platelets–> platelet dysfunction & platelet aggregation
decreased anticoagulant leading to thrombosis
decreased antifibrinolysis
Treatment of DIC includes:
recognition
treat the underlying condition- infection give abx or trauma resus or removal of insult
& supportive
Describe the supportive treatments of DIC
platelets cryo fibrinogen concentrate FFP heparin, TX PCCs (contain fewer natural anticoagulants than FFP)
Throbomodulin binds to
thrombin and decreases the proinflammatory response
limited clinical trials
Thrombin is a
potent proinflammatory protein & platelet aggregator
neutralizing thrombin effect is crucial
can give throbomodulin
direct thrombin inhibitors- no RCTs yet
The use of heparin in DIC is
used historically with variable outcomes
reserved for early or highly prothrombotic states
high risk of additive bleeding
has been shown to reduce end-organ dysfunction
often discontinued if/when overt bleeding starts
difficult to monitor because PTT is already prolonged due to coagulation factor consumption
In severe trauma, excessive _____ is generated to rescue the host from excessive bleeding
thrombin
Early hyperfibrinolysis may be treated with
tranexamic acid
-consider single upfront bolus during acute period as later the balance is tipped toward thrombosis
In a severe trauma while thrombin is being generated, ______ is also generated
plasmin which breaks down the microvascular clot
unfortunately it is not able to isolate leading to widespread hemorrhage
Blood product support for DIC includes
platelets–> cryo or fibrinogen concentrate–>FFP
In presenting procoagulant DIC- consider
anticoagulation first & blood product support for bleeding or invasive procedures
-LMWH (thrombomodulin trial stages only)
In presenting hyperfibrinolysis over procoagulant process is anticipated provide
TXA along with blood product support
once bleeding has been controlled, consider anticoagulant treatment to control the ongoing thrombin generation
A thorough history for patients with clotting disorders should include
excessive bleeding after dental extraction?, medications such as ASA, NSAIDs, or gingko, family history of inherited bleeding disorders
Some healthy individuals may have
abnormal lab values and patients with mild hemophilia or vWD may not display abnormal values
