heparin-induced thrombocytopenia - …williams.medicine.wisc.edu/dic.ppt · ppt file · web...
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DISSEMINATED INTRAVASCULAR DISSEMINATED INTRAVASCULAR COAGULATIONCOAGULATION
SOLUBLE FIBRIN IN DICSOLUBLE FIBRIN IN DIC
MONKEY (E. COLI INJECTION) HUMAN (ACUTE LEUKEMIA)
→Non-adherent/soluble fibrin, no platelets
• Blood exposed to excess tissue factor Endothelial damageTissue factor expression by monocytesMassive tissue/organ injuryCancerObstetric catastrophe
• Activation of fibrinolysisSecondary to thrombin formation (t-PA)Cancer/leukemia (t-PA, u-PA, other)Cardiopulmonary bypass
• Other procoagulant or profibrinolytic substancesCancer cellsVenoms
CAUSES OF DICCAUSES OF DIC
VASCULAR SUBENDOTHELIUM AND VASCULAR SUBENDOTHELIUM AND CIRCULATING MONOCYTES ARE POTENTIAL CIRCULATING MONOCYTES ARE POTENTIAL
SOURCES OF TISSUE FACTORSOURCES OF TISSUE FACTOR
LARGE VESSEL MONOCYTEMONOCYTE
+ ENDOTOXIN
SMALL VESSEL
Am J Pathol 1989; 134:1087-97
INFLAMMATORY CYTOKINES INDUCE GAPS IN INFLAMMATORY CYTOKINES INDUCE GAPS IN ENDOTHELIAL MONOLAYERENDOTHELIAL MONOLAYER
J Exp Med 1989;169:1977-91
Control 5 nM TNF x 90 min 5 nM TNF x 24h
Cytokine-induced endothelial damage in the microcirculation exposes blood to a large pool of subendothelial tissue factor
BACTERIAL LIPOPOLYSACCHARIDE INDUCES TISSUE BACTERIAL LIPOPOLYSACCHARIDE INDUCES TISSUE FACTOR mRNA EXPRESSION IN HEALTHY VOLUNTEERSFACTOR mRNA EXPRESSION IN HEALTHY VOLUNTEERS
Franco et al, Blood 2000;96:554-9
Tissue factor mRNA Thrombin
Dvorak et al, 1981
Cancer cells shed tissue factor-rich membrane Cancer cells shed tissue factor-rich membrane vesiclesvesicles
Fibrin deposits around tumor cells
Intravascular fibrin
LEUKEMIC CELLS EXPRESS A VARIETY OF LEUKEMIC CELLS EXPRESS A VARIETY OF PROCOAGULANT AND PROFIBRINOLYTIC PROCOAGULANT AND PROFIBRINOLYTIC
SUBSTANCESSUBSTANCES
Tissue factor
Urokinase
tPA
ElastaseCytokines
Annexin II
• Inflammation (TNF, IL-1, IL-6, etc) Upregulation of procoagulant pathways Downregulation of profibrinolytic pathways Effects on endotheliumIncreased risk of tissue damage/organ failure
• Liver disease Inhibitor deficiency (antithrombin,
antiplasmin, protein C, etc) Diminished clotting factor production Delayed clearance of FDPIncreases severity of DIC, may increase
bleeding risk
INFLAMMATION AND LIVER DISEASE PROMOTE DICINFLAMMATION AND LIVER DISEASE PROMOTE DIC
ANTIPRO
ANTI
PRO
ANTIPRO
Normal
Inflammation Liver disease
A tipped scale An unstable balance
Bacterial lipopolysaccharide (LPS) induces fibrin deposition in rat Bacterial lipopolysaccharide (LPS) induces fibrin deposition in rat kidney more efficiently than tissue factor (TF)kidney more efficiently than tissue factor (TF)
Asakura et al, Crit Care Med 2002;30:161
TNF levels correlate strongly with mortality in TNF levels correlate strongly with mortality in children with infectious purpura fulminanschildren with infectious purpura fulminans
NEJM 1988;319:397-400
TNF level (ng/ml)0
20
40
60
80
100
Mor
talit
y (%
)
Under 0.15
0.15-0.50
0.50-1.00
Over 1.00
•Bleeding
•Thrombosis
•Tissue necrosis
COMPLICATIONS OF DICCOMPLICATIONS OF DIC
• Clotting factor consumption
• High levels of FDP (inhibit fibrin formation)
• Endothelial damage
• Increased fibrinolytic activity
CAUSES OF BLEEDING IN DICCAUSES OF BLEEDING IN DIC
FIBRINOLYSISFIBRINOLYSIS
Plasminogen
Plasmin
TPA UK
Fibrin FDP Fibrinogen
2PI 2PI
Fibroblasts
Macrophage
Liver
Platelets
Fibrin catalyzes its own destruction
PAI-1
Endothelial cell
Depletion of platelets & antiplasmin increases systemic fibrinolysis
Bleeding severity correlates with low antiplasmin activityBleeding severity correlates with low antiplasmin activity
< 50% 50-75% > 75%Antiplasmin activity
0
20
40
60
80
100
% o
f pat
ient
s
0-2+ bleeding
3-4+ bleeding
Arch Intern Med 1989;149:1769
• Acute leukemia (particularly promyelocytic)• Metastatic cancer (esp. prostate)• Cardiopulmonary bypass• Liver disease or transplantation
DIC WITH HYPERFIBRINOLYSISDIC WITH HYPERFIBRINOLYSISExamples
• Large vessel thrombosis uncommon Disordered clotting Increased fibrinolysis
• More common in "chronic DIC" e.g., Trousseau syndrome
• Clots may form around intravascular catheters, etc
THROMBOSIS IN DICTHROMBOSIS IN DIC
TISSUE INJURY IN DIC:TISSUE INJURY IN DIC:PUPURA FULMINANSPUPURA FULMINANS
Pneumococcal sepsis in a splenectomized patient
NEJM 2001;344:1593
High level bacteremia
NEJM 2004;351:2636
PURPURA FULMINANS IN MENINGOCOCCEMIAPURPURA FULMINANS IN MENINGOCOCCEMIA
NEJM 2001;344:1372
Blood 2005;105:11
High level bacteremia
ADRENAL GLAND(Waterhouse-Friderichsen syndrome)
NEJM 2005;353:1245
RENAL CORTEX
PURPURA FULMINANS IS OFTEN ASSOCIATED PURPURA FULMINANS IS OFTEN ASSOCIATED WITH MULTIPLE ORGAN FAILUREWITH MULTIPLE ORGAN FAILURE
Hum Pathol 1972;3:327
• Intravascular fibrin• Endothelial damage• Downregulated fibrinolysis• Hypotension• Pressor administration• Acquired protein C deficiency
TISSUE NECROSIS AND DICTISSUE NECROSIS AND DIC(PURPURA FULMINANS)(PURPURA FULMINANS)
Contributing factorsContributing factors
• Physiologic anticoagulant Vitamin K-dependent Destroys factors Va, VIIIa (Protein S is cofactor)
• Activated by thrombin bound to endothelium Activation downregulated by inflammatory cytokines
• Protective effect on endothelium Protein C receptor on endothelial cells Activated protein C modulates endothelial response to
inflammation and hypoxia
Severe deficiency of protein C can cause tissue necrosis
PROTEIN CPROTEIN C
ACTIVATED PROTEIN C HAS ANTICOAGULANT ACTIVATED PROTEIN C HAS ANTICOAGULANT AND CYTOPROTECTIVE EFFECTSAND CYTOPROTECTIVE EFFECTS
Blood 2007; 109:3161
HOMOZYGOUS PROTEIN C DEFICIENCY WITH HOMOZYGOUS PROTEIN C DEFICIENCY WITH NEONATAL PURPURA FULMINANSNEONATAL PURPURA FULMINANS
WARFARIN-INDUCED SKIN NECROSIS IN WARFARIN-INDUCED SKIN NECROSIS IN A PROTEIN C-DEFICIENT PATIENTA PROTEIN C-DEFICIENT PATIENT
PURPURA FULMINANS IN A PATIENT WITH PURPURA FULMINANS IN A PATIENT WITH AN ACQUIRED INHIBITOR OF APCAN ACQUIRED INHIBITOR OF APC
With normally lethal dose of E. coli:Activated protein C prevents DIC, tissue
necrosis and deathAnother inhibitor of thrombin formation blocks
DIC but not tissue necrosis and death
With normally sublethal dose of E. coli:Monoclonal antibodies to either protein C or its
endothelial receptor promote DIC, tissue necrosis and death
PROTEIN C IN BACTERIAL SEPSISPROTEIN C IN BACTERIAL SEPSISBaboon model
F.B. Taylor et al, J Clin Invest 1987; Blood 1991; Blood 2000
Protein C levels predict ICU survival as well as the Protein C levels predict ICU survival as well as the APACHE II or SAPS II scoreAPACHE II or SAPS II score
Anesthesiology 2007;107:15
• Excess tissue factor + flowing blood = DIC• Inflammatory cytokines set the stage for DIC and
contribute to tissue damage• Excessive fibrinolysis associated with higher
bleeding risk• Acquired protein C deficiency associated with high
risk of tissue necrosis/purpura fulminans
DIC PATHOPHYSIOLOGYDIC PATHOPHYSIOLOGYSummary
DIC is likely when there is:
1. A condition known to cause DIC2. Evidence of accelerated fibrinolysis and
clotting factor consumption
DIAGNOSIS OF DICDIAGNOSIS OF DIC
LABORATORY TESTS IN DICLABORATORY TESTS IN DIC
DIAGNOSISDIAGNOSIS GUIDE GUIDE TREATMENTTREATMENT
FDP or D-Dimer PT/INR
Fibrinogen Fibrinogen
PT/INR Platelet count
Platelet count Alpha2-antiplasmin
Fibrin monomer
DDeatheath
IIss
CComingoming
SEVERE DIC IS ASSOCIATED WITH A HIGH SEVERE DIC IS ASSOCIATED WITH A HIGH MORTALITY RATEMORTALITY RATE
• 346 patients with overt DIC• 77% bled excessively• 68% died
– 72% with bleeding– 63% without bleeding
Most deaths from underlying disease, not bleeding
Thromb Haemost 1980; 43:28-33
TREATMENT OF DICTREATMENT OF DIC• TREAT UNDERLYING DISEASE!
• Clotting factor & inhibitor replacementFresh frozen plasmaCryoprecipitatePlateletsAntithrombin III concentrate?Activated protein C concentrate
• Pharmacologic inhibitorsHeparin Antifibrinolytics
REPLACEMENT THERAPY IN DICREPLACEMENT THERAPY IN DIC
Product Content Indication Risk
FFP All clotting factors and inhibitors INR > 1.6 Volume
virus transmission
Cryoprecipitate Fibrinogen, VIII, VWF Fibrinogen < 50-100 "Feed the fire"?
Platelets Platelets < 30-50K
Antithrombin Purified antithrombin ? ?
Activated protein C* Recombinant APC Severe sepsisPurpura fulminans? Bleeding
*Withdrawn from market - 2011
IS THERE A ROLE FOR ANTICOAGULANT OR IS THERE A ROLE FOR ANTICOAGULANT OR ANTIFIBRINOLYTIC DRUGS IN DIC?ANTIFIBRINOLYTIC DRUGS IN DIC?
• No controlled trials have shown any benefit• Anecdotal evidence suggests these drugs
may help selected patients• Consider using such treatment in patients
with life-threatening bleeding that persists despite aggressive replacement therapy
HEPARIN IN DICHEPARIN IN DICRationale: Prevent thrombin/fibrin formation
and secondary fibrinolysis
Indications: Cancer-associated DICAcute leukemia and DICChronic DIC with aneurysm, etcOvert thrombosis (full dose heparin)Adjunct to antifibrinolytic Rx
Risks: Exacerbate bleeding (unlikely w/low dose)
Low dose (eg, 500 U/hr) of unfractionated heparin usually adequate
ANTIFIBRINOLYTIC DRUGS
Lysine analogs block binding of tPA and plasminogen to lysine residues on fibrin
ANTIFIBRINOLYTIC THERAPY IN DICANTIFIBRINOLYTIC THERAPY IN DIC
Rationale: Inhibit activation of plasminogen/clot lysisPrevent bleeding
Indications: DIC in promyelocytic leukemiaDIC with severe bleeding, low antiplasmin
Risk: Thrombosis uncommon (give w/heparin)Blanket contraindication in DIC unjustified
Amicar, 1 gram/hour i.v. with low dose heparin
COMBINED ANTICOAGULANT AND ANTIFIBRINOLYTIC COMBINED ANTICOAGULANT AND ANTIFIBRINOLYTIC TREATMENT OF DIC ASSOCIATED WITH PROSTATE CARCINOMATREATMENT OF DIC ASSOCIATED WITH PROSTATE CARCINOMA
60 yo man post XRT for spine mets with diffuse bleeding60 yo man post XRT for spine mets with diffuse bleeding
1 2 3 4 5 6 7 8DAY
0
50
100
150
200
250
300
Fibr
inog
en, m
g /dl
0
50
100
150
200
250
Platelets
• Subjects: 36 patients with meningococcemia, shock and purpura fulminans Mean age = 12 (3 months-72 yrs) Mean protein C activity 18%
• Intervention: Protein C concentrate, 100 IU/kg loading dose and 10 IU/kg/hr, adjusted to keep protein C activity in 80-120% range Two patients also received antithrombin concentrate
PROTEIN C REPLACEMENT IN PURPURA PROTEIN C REPLACEMENT IN PURPURA FULMINANSFULMINANS
A prospective, open-label clinical trialA prospective, open-label clinical trial
Blood 2000;96:3719
OUTCOME OBSERVED PREDICTED
Death 8% 50%
Amputation 12% 30%
• Subjects: 1690 patients with severe sepsis• Method: randomized, double-blind, placebo-
controlled multicenter trial• Intervention: rAPC infusion vs placebo• Outcomes:
Mortality lower in treated pts (24.7% vs 30.8%, p=.005)Serious bleeding more common in treated pts (3.5% vs
2%, p=.06)Subgroup analysis suggests greatest benefit in patients
with more severe sepsis & DIC
RECOMBINANT ACTIVATED PROTEIN C RECOMBINANT ACTIVATED PROTEIN C INFUSION IN SEVERE SEPSISINFUSION IN SEVERE SEPSIS
NEJM 2001;344:699
Effects of rAPC infusion on survival and D-dimer Effects of rAPC infusion on survival and D-dimer levels in patients with severe sepsislevels in patients with severe sepsis
NEJM 2001;344:699
Survival D-dimer