Disseminated Intravascular Coagulation (DIC) in Pregnancy A NOVA SCOTIAN PERSPECTIVE

Disseminated Intravascular
Coagulation (DIC) in Pregnancy
A NOVA SCOTIAN
PERSPECTIVE
DARRIEN RATTRAY PGY4
DR THOMAS BASKETT
SEPT 29, 2010
Obstetrical DIC
De Lee JB. Am J Obstet Dis Women Child (1901) 44: 785-92
De Lee 1901
 “Mrs H, 35 years of age, IV para, German”
 “At 2 AM of the 13th she awoke with a pain in the
abdomen…she sent for me about 7 and I arrived at
8:20”
 “The pulse was full and bounding, but the patient
was pale…the uterus…now very hard, large,
symmetrical, and tender. No heart tones”
 “Diagnosed premature detachment of the
placenta…the flow soon became profuse”
 “With the help of the husband alone I put her on the
table and prepared the parts…”
De Lee 1901
 “…gave a hypodermic of strychnine and a large,
bloody infiltration of the skin and subcutaneous
tissue took place…”
 “…salt solution, one quart, was injected…Deep blue
ecchymoses appeared around the puncture and
extended up into the axilla, blood oozing persistantly
from the hole and not to be stopped with plaster”
 “…I tried to do a version, but the hands, tired with
two hours’ hard operating, were paralyzed”
De Lee 1901
 “Placenta was loose in the cavity, which was filled
with old, dark, firm, almost black clots…dark, thin,
almost lake-coloured blood followed”
 “There was no atony here…”
 “…before we could retampon with gelatin gauze she
became unconscious and died. It was three hours
from the time I started and ten hours from the onset
of first symptoms”
De Lee 1901
 “Is there such a disease as acquired hemophilia?”
 “The causes of this are unknown; consanguinity of
marriage, tuberculosis, gout, maternal mental shock
during gestation…”
 “Does the loss of blood favor further hemorrhage per
se?...the blood that is lost is light and watery, not
dark”
 “…I believe…there is such an affection as a
temporary hemophilia, but the demonstration of the
same, I admit, presents no little difficulty”
Objectives
 Provide an overview of coagulation
 Describe the pathophysiology & etiology of DIC in
obstetrics
 Discuss approach to treatment of DIC in pregnancy
 Review 30 years of obstetrical DIC in the IWK
Coagulation 101
• PRIMARY HAEMOSTASIS
Coagulation
•
Formation of platelet plug at site
of endothelial injury
• SECONDARY HAEMOSTASIS
•
Formation of Fibrin clot
Intrinsic pathway
• Extrinsic pathway
• Common pathway
• FIBRINOLYSIS
•
Primary Haemostasis
 Interaction between
platelets, vWF, and the
vessel wall

Endothelium important
 Platelet plug is unstable
 Requires formation of
organized fibrin clot
 Important in
pathogenesis of DIC



Sepsis
Preeclampsia
Hypovolemic shock
Secondary Haemostasis
Scanning Electron Microscopy of a
cross-linked fibrin clot
Haemostasis and the Lab
 PT (Prothrombin Time)
 Reflection of the extrinsic & common pathway
TF, Factor VII
 Prothrombin, Factors V and X, Fibrinogen
 Normal 9.0-11.0 sec at IWK


Play Tennis outside (extrinsic)
 aPTT (Activated Partial Thromboplastin Time)
 Reflection of the intrinsic & common pathways
All factors except VII
 Normal 24.1 – 31.6 sec at IWK


Play Table Tennis inside (intrinsic)
Fibrin Degradation Products & D-Dimers
 Measurements of Fibrinolysis
 May be measured with Fibrin Degradation Products
(FDPs)


Do not discriminate between products of cross-linked fibrin
and fibrinogen (limits specificity)
Newer assays for cross-linked fibrin degradation products (Ddimers)
 Many other conditions have ↑ D-dimers
 Trauma
 Recent surgery
 Venous thromboembolism
 Pregnancy
What is DIC?
S Y S T E M I C T H R OBleeding
M B O H E&M
Clotting
ORRHAGIC DISORDER
SEEN IN ASSOCIATION WITH WELL-DEFINED
CLINICAL SITUATIONS AND LABORATORY
EVIDENCE OF:
1.
2.
3.
4.
Procoagulant activation
Fibrinolytic activation
Inhibitor consumption
Biochemical evidence of end-organ damage or failure
Bick RL. Hematol Oncol Clin N Am (2003) 17: 149-76
Processes in DIC
Levi et al. Br J Haematology (2009) 145: 24-33.
Objective Approach
 Multitude of tests with multiple variables affecting
results makes diagnosis confusing
 Analysis of 900 pts with DIC (non-pregnant)

Thrombocytopenia > Elevated FDP > prolonged PT >
prolonged aPTT > low fibrinogen
 International Society for Thrombosis and
Haemostasis (ISTH) developed a more objective
scoring system for the diagnosis of DIC

Compared to blinded “expert” assessments for DIC, found to
be 91% sensitive and 97% specific
Bakhtiari et al. Crit Care Med (2004) 32: 2416-21
What is Obstetrical DIC?
PROBLEMS WITH DIC IN PREGNANCY
1.
2.
3.
No universally accepted definition of DIC
Great spectrum of manifestations
Normal pregnancy state is hypercoagulable
Pathogenesis of DIC in Pregnancy
 Three main triggers



Endothelial injury
Thromboplastin release
Phospholipid exposure
 End result = generation
of thrombin with ↑ fibrin
deposition
 Many pathologies
overlap…
Letsky EA. Best Pract Res Clin Obs Gynecol (2001) 15: 623-44.
Diagnosis of Obstetrical DIC
 Almost all coagulation factors are elevated in
pregnancy



Marked shortening of PT and aPTT
Consumption of coagulation factors may elevate the PT and
aPTT but be still within normal non-pregnant ranges
Important to assess serial changes in PT and aPTT
 Similar problem with platelet count
 Fibrinogen levels can double in pregnancy
 Not all cases of DIC have low fibrinogen
Thachil et al. Blood Reviews 23 (2009) 167-176.
Spectrum of DIC in Obstetrics
Severity of DIC
In vitro Findings
Obstetric Conditions
Commonly Associated
Stage 1: Low-grade
compensated
↑ FDPs
↓ Platelets
Pre-eclampsia and related
syndromes
Stage 2: Uncompensated As above plus:
but no haemostatic
↓↓ Platelets
↓ Fibrinogen
failure
↓ Factors V and VIII
Small Abruptio
Severe Pre-eclampsia
Stage 3: Rampant with
haemostatic failure
Abruptio placentae
Amniotic Fluid Embolism
Eclampsia
As above plus:
↓↓ Platelets
Gross depletion of
coagulation factors
(particularly fibrinogen)
↑↑ FDPs
***Rapid progression may occur if underlying cause not treated
Adapted from Letsky EA. Best Pract Res Clin Obs Gynecol (2001) 15: 623-44.
Thrombocytopenia
 Feature of ~98% of DIC cases
 Platelet count <50 x 109 in ~50%
 Correlates to Thrombin generation

Thrombin-induced platelet aggregation is mainly responsible for
platelet consumption
 Low or decreasing platelet count not very specific for DIC
as many conditions that are associated w/ DIC have low
platelets




Gestational Thrombocytopenia
HELLP
Sepsis
Leukemia
aPTT and PT
 Prolonged in 50-75% of cases of DIC at some point in
their illness
 Several causes



Consumption of coagulation factors
Abnormal synthesis in the liver
Loss of proteins with massive bleeding
 Times may actually be shortened initially (~50%)
 ↑ activated circulating clotting factors
FDP & D-Dimers
 Elevated in 85-100% of patients with DIC
 Non-specific
 Problems in pregnancy
 Nishii et al (2009)
 Examined levels of D-dimers in 1131 pregnancies
1.1 ± 1.0 µg/ml in 1st trimester
 2.2 ± 1.1 µg/ml in 3rd trimester

Nishii et al. J Obstet Gynaecol Res (2009) 35:689-93
FDP…not just a marker
 Fibrin degradation products also implicated in the
pathophysiology of obstetrical DIC



Impair fibrin monomer polymerization (i.e. prevent crosslinking of fibrin and formation of new clots)
Coat platelet membranes resulting in decreased platelet
function
Impairs myometrial contractility


May be cardiotoxic


Worsens atonic PPH
Low cardiac output and blood pressure = ↓ organ perfusion
Induce synthesis of inflammatory cytokines
Bick RL. Hem Onc Clin North Am (2000) 14: 999-1034.
Fibrinogen in Obstetrical DIC
 Elevated as part of normal pregnancy
 Can be used as a predictor of PPH severity (often
linked with DIC)



Data from 128 women with PPH analyzed
Analyzed serial coagulation tests
Fibrinogen was the only marker associated with the occurrence
of severe PPH
NPV of FG > 4g/L = 79%
 PPV of FG < 2g/L = 100%

Charbit et al. J Thromb Haemost (2007) 5: 266-73
Treatment of Obstetrical DIC
1. TREAT THE OBSTETRICAL ABNORMALITY!!
2. REPLACE BLOOD PRODUCTS
•
Massive Transfusion Protocol
3. TREAT ACIDOSIS, HYPOTHERMIA, AND
HYPOCALCEMIA
4. THERAPY HIGHLY INDIVIDUALIZED
Mercier et al. Curr Opin Anaest (2010) 22: 310-16.
Blood Products
 PRBCs


Improve O2 carrying capacity
Transfuse based on physical exam, vitals, and ongoing loss
 FFP


Contains all plasma proteins and clotting factors
Transfuse if microvascular bleeding from clotting factor deficiency
 Cryoprecipitate


Contains clotting factors and high concentrations of fibrinogen
Use if fibrinogen <1.0 g/L and volume status is a concern
 Platelets


1 adult dose should ↑ plt count by 25-30
Use if microvascular bleeding and plt count <50
Mercier et al. Curr Opin Anaest (2010) 22: 310-16.
IWK Massive Transfusion Protocol
 Guiding Principles
 Volume resuscitation with PRBCs as soon as available
 Little evidence for standardized ratios in pregnant women but
ratio of 2:1:1 (PRBC:FFP:Plts) may be beneficial
 Maintain low-normal BP and prevent hypothermia & acidosis
 Use PRBCs <14 days old
 Balance is key (avoid large volumes of crystalloid)
 Use O- until ABO/Rh type are confirmed
 Early contact with Blood Bank
IWK Massive Transfusion Protocol
 Activate MTP if:
 Request for emergency PRBCs
 Expecting to lose one blood volume within first 24 hours (~5L
in 70 kg patient)
 Predicting loss of >50% blood volume within a 3 hour period
 Ongoing loss of >15ml/kg/hr
 Concern by the Medical Lead
IWK Massive Transfusion Protocol
 Identify MTP co-ordinator
 Facilitate transfusions and records use of products
 Assigns associated tasks
 Notifies blood bank and provides patient info
BLEED order set in Meditech
 Arterial Blood Gases
 Ionized calcium
 Lactate
 Electrolytes
 BCP (CBC without WBC differential)
 INR, PTT, fibrinogen
 Collect every 30-60 min depending on clinical situation

IWK Massive Transfusion Protocol
 Counter the complications of massive transfusion





Ionized Calcium >1.13 mmol/L
Urine output >30 cc/hr (>0.5cc/kg/hr)
SBP low-normal for age or stability
Temperature >35 °C
pH >7.10
 Consider the use of adjuvant Tx

Antifibrinolytics (Cyklokapron)


Recombinant Factor VIIa


10mg/kg IV (max 1g/dose)
20 – 50 µg/kg/dose IV
Prohemostatic drugs (DDAVP)

10µg/m2 IV (max 20 µg)
IWK Massive Transfusion Protocol
 May discontinue MTP if:
 Hgb > 70
 INR < 1.7
 Platelet count >50
 Fibrinogen > 1.0
 Resolution of shock and no evidence of bleeding
The Silver Bullet of PPH?
Recombinant Factor VIIa
 Produced from
hamster kidney cells
 Involves extrinsic &
intrinsic pathways
 Results in a “thrombin
burst” to form a strong
stable clot at the site of
vessel injury
rFVIIa
 Approved for use in congenital coagulation
deficiencies and inherited platelet disorders


First off-label use in a wounded soldier in 1999 with no
bleeding disorder
First off-label use in obstetrics was in 2001 following PPH after
C-section
 Largest meta-analysis in non-OB cases in 2008
 22 RCTs; 3184 patients
 Reduction in # of blood transfusions (OR 0.54)
 Possible reduction in mortality (OR 0.88; CI 0.71-1.09)
 No increased risk of VTE (1% in both groups)
 Mild increased risk of arterial thrombosis (OR 1.50)
Hsia CC et al. Ann Surg (2008) 248: 61-68.
Risks of rFVIIa
 FDA’s Adverse Event Reporting System (AERS)
reviewed (1999-2004)

431 AE reports for rFVIIa; 185 thromboembolic events




Used ~9000 times in timeframe studied
35% in unlabeled indications (most with active bleeding)
CVA (39), MI (34), arterial thrombosis (26), PE (32), DVT
(42), clotted devices (10)
50 reported deaths (72% due to thromboembolic event)
Registry Safety Data
 Northern Europe Factor VIIa in Obstetric Hemorrhage
Registry




9 European countries (2000-2004)
Reported use in 128 patients
4 cases of DVT
One MI (had cardiac arrest prior to rFVIIa)
 Australian and New Zealand Registry


27 cases of rFVIIa in obstetrical hemorrhage
No adverse effects reported
 Italian Registry on use of rFVIIa in severe PPH


35 cases
No adverse effects reported
rFVIIa & PPH
 Franchini et al (2010)
 9 studies; 272 patients; Median age 31; Median dose 81.5
µg/kg
 Efficacy in stopping or reducing bleeding = 85%




Failures attributed to inadequate dosages, unrecognized surgical
bleeding, and severe metabolic abnormalities
Adverse events in 2.5% of cases (all thrombotic episodes)
Should not be considered a substitute for performing invasive
procedures (embolization, conservative surgery)
Could consider use before hysterectomy
Franchini M et al. Clin Obstet Gynecol (2010). 53: 219-27.
rFVIIa & PPH with DIC
 Franchini et al (2007)
 32 cases from 15 studies
 Median age 33.3 years
 Uterine atony #1 cause of PPH
 Majority delivered via C/Section (76%)
 Hysterectomy in 56%
 Single dose of rFVIIa successful in 81%


Cessation or significant reduction in blood loss
No reports on safety
Franchini et al. Blood Coag Fibrin (2007) 18: 589-93.
Proposed
Algorithm for
rFVIIa in PPH
Franchini et al. “The
Use of Recombinant
Activated FVII in
Postpartum
Hemorrhage”. Clin
Obstet Gynecol. 2010.
53: 219-227.
Committee Opinions on rFVIIa
 Conservative use is currently endorsed by:
 The French health safety agency (AFSSAPS)
 Several European and Australian-New Zealand
multidisciplinary expert panels
Suggest giving 90 µg/kg after all definitive procedures attempted,
and 8-12 U PRBCs given but before hysterectomy
 May repeat dose after 20 min if still bleeding
 If still no response, proceed to hysterectomy

 SOGC 2009 PPH guidelines
 “Evidence for the benefit of recombinant activated factor
VII has been gathered from very few cases of massive PPH.
Therefore this agent cannot be recommended as part of
routine practice. (II-3L)”
Welsh A et al. (2008) Aust NZ J Obstet Gynaecol. 48: 12-16.
Practical rFVIIa tips
 Produced under trade name Niastase
 Available in glass vials of 1.2, 2.4, or 4.8 mg
 White lyophilized powder needs to be reconstituted in




sterile water
Store at 2-8 °C
Administer within 3 hours of reconstitution
Give as IV bolus over 3-5 minutes
Soon coming in vials of 1, 2, & 5 mg at concentration of 1
mg/ml

Can store at room temp
 ***$1 per µg!...average dose ~$6300***
Tranexamic Acid (Cyklokapron™)
 Cochrane review (2007) for non-OB surgery



Reduced risk of blood transfusion (RR 0.61; CI 0.54-0.69)
Reduced need for re-operation from bleeding (RR 0.67; CI 0.41-1.09)
No increased risk of VTE
 3 RCTs on PPH prevention



461 patients
Reduction in PPH incidence (RR 0.4; CI 0.32-0.64)
No VTE
 WHO guidelines state that tranexamic acid may be used
in PPH if other measures fail

Acknowledge low quality of evidence
 Two large prospective trials of Tranexamic acid and PPH
currently underway
Mercier et al. Curr Opin Anaest (2010) 23: 310-16.
The Nova Scotian Experience
Atlee Database &
Chart Review
(1980-2009)
• 72 cases
identified by
Atlee
Database
• 62 charts
reviewed
• DIC likely in
48 cases
•
ISTH and
Letsky
criteria
 Demographics
 Average age = 28.1 years
 Nulliparous = 27
 Multiparous = 21
 Average gestational age = 35.4 weeks
 Average stay in hospital = 11.7 days
 Average pre-pregnancy wt = 65.6 kg
 14 cases excluded
 Miscoded
 Other coagulopathies
 Other thrombocytopenias with no
coagulation abnormalities
Mode of Delivery
C/S = 46%
SVD
SVD = 40 %
6
1
Operative vaginal
delivery = 14%
19
C/S (labor)
C/S (no labor)
11
11
FAVD
Vacuum
Causes of DIC
Abruptio
Placentae
•
#1 = Abruption
•
3
38%
4
•
•
18
#2 = PPH
•
29%
7
15%
Preeclampsia
AFLP
#3 = Preeclampsia
•
PPH
2
14
Sepsis
AFE
PPH Associations
Atony
• PPH
documented in
38 cases
3
9
21
• Causes of PPH
often overlap
Genital Tract
Trauma
RPOC
11
Accreta
PPH
Management
Surgical
Management
1
3
3
9
Hysterectomy
Compression
sutures
4
Vessel Ligation
Note high rate of
emergency
hysterectomy
(24%)
Embolization
Tamponade
Medical
Management
Misoprostol
8
0
10
14
19
20
Ergot
Hemabate
Blood Products
 PRBCs

0 – 23 units (avg 7.5)
 FFP

0 – 5600 cc
 Cryoprecipitate

0 – 20 units (avg 9.5)
 Platelets

0 – 30 units (avg 11.2)
 Albumin

0 – 2000 cc
 rFVIIa

Used in 1 case (2 units)
Morbidity & Mortality
 ICU stay


18 patients
Range 1-8 days
 ATN requiring dialysis

3 patients
 Emergency Hysterectomy

9 patients (3/9 primiparous)
 Maternal mortality

3 patients (6.25%)
1 fulminant DIC w/ uncontrollable hemorrhage
 1 fulminant DIC refusing blood products
 1 intracerebral hemorrhage

Neonatal Outcomes
Total of 52
infants born to
48 mothers
•
4 sets of twins
•
69% lived
•
25% died in utero
•
6% died as neonates
•
28 NICU admissions
•
Gestational Ages
•
•
•
< 33 weeks = 15
34-36 weeks = 14
37+ weeks = 23
3
13
36
Living
Fetal Death
Neonatal Death
Birthweights
• VLBW = 500 -
Normal
<1500g
•
10
1 infant <500g
• LBW = 1500 -
25
<2500g
• Normal = 2500g
and above
17
LBW (but not
VLBW)
VLBW
Conclusions
 DIC is a rare but serious entity in modern obstetrics
 High morbidity and mortality (6.25%)
 DIC is difficult to diagnose and we must have a high
index of suspicion when dealing with pathologies
known to cause DIC

Mild untreated DIC can rapidly progress to fulminant
haemostatic failure
 Treatment of DIC is aimed at the underlying cause
plus supportive therapy

Proposed role for rFVIIa prior to hysterectomy
Thank You
QUESTIONS?