Transcript Pathophysiology, prophylaxis, treatment DVT and PE Anton Sharapov

DVT and PE
Pathophysiology,
prophylaxis, treatment
Anton Sharapov
Cases to consider
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38
65
65
25
25
75
65
yom for elective IHR
yom for elective IHR
yom, obesity/CHF/prev DVT for IHR
yof post severe head injury
yom post trauma/abdo/chest
yof post hip #
yom post THA, obese
Scope of the problem
P Common postop complication
P Asymptomatic > symptomatic
P Difficult to study
P Most studies evaluate asymptomatic pts
Epidemiology
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VTE 48:100,000
PE 69:100,000
Incidence – 20-70% surgery pts
½ begin in OR
Epidemiology
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DVT and PE – different stages of same
disease process
10% proximal DVTs progress to
symptomatic PE
25% distal DVTs become proximal
Outcomes
P Most asymptomatic VTE recover
sans treatment and complications
P Less then 1 in 8 confirmed clots
progress to symptomatic
thromboembolic disease
P Important to observe clots over a
period of time
Outcomes of PE
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Outcomes of PE are difficult to assess
Registry estimates are always higher
then in clinical studies (7% vs 2%)
Mortality is a function of RV function,
clot burden, and comorbidities
Risk of fatal PE greatest 3-7 postop
Asymptomatic PE are common
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40% of asymptomatic prox DVTs
Assessment
P Assess risk of DVT and risk of
bleeding
P Assess duration of prophylaxis
P Assess Virchov triad
P Venous stasis
P Endothelial injury
P hypercoagulability
Risk factors: venous stasis
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P
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P
P
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Immobility & tourniquet application
Institutionalization
CVA
Paralysis
CHF
Travel >4 hours
Obesity
Respiratory failure
Varicose veins
Duration/extent of postop immobilization
Risk factors: endothelial injury
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Trauma
Atherosclerosis
Perioperative
Malignancy
Post-phlebitic syndrome
Prior DVT
CV catheter
Inflamatory condition
Hyperhomocysteinemia
Risk factors:
hypercoagulability, Acquired
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Post op
Malignancy
Hormone replacement
Estrogen therapy
Risk factors:
hypercoagulability, Acquired:
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Antiphospholipid antibody
Lupus anticoagulant – 5-10 fold risk
Myeloproliferative d/o
Paroxysmal nocturnal hemoglobinuria
Nephrotic syndrome
Pn loosing enteropathy
Risk factors:
hypercoagulability, Inherited:
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Factor V leiden – APC resistance
B Absolute risk post op VTE is small - 1/100
B Relative risk increased (3-5 fold)
B Screening not recommended
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Antithrombin, pn C/S deficiency
Fibrinogen/TPA defects
Prothrombin gene mutation
Risk factors: Miscelaneous
P Use/nonuse of thrombopophylactic
measures
 Age - rises linearly after 40
P Ethnicity:
 Asian/South Pacific - threefold lower
 African American - slightly higher
 Latin - slightly lower
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Site/extent traumatic injury
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Knee/spine=major trauma>hip>uro/gyny>
neuro>general/thoracic
Risk of DVT, miscellaneous
P Surgical procedure - most important
Neurosurgery & ortho - 6% & 3%
Major vascular
Bowel, bladder, gastric bypass and kidney
transplant
Radical neck, IHR, lap chole (0.3%),TURP,
thyroid/parathyroid - lowest risk
Need for global integrative
assessment
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American College of Chest Physicians
Risk stratification tool
Problems:
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What defines major vs minor surgeries?
No weighting of Risk Factors
Why age 40 and 60 important?
Patient RF
low
Age<40
No RF
mod Age>40
Immobilization
Obesity
Malignancy
high Hx of DVT
Thrombophilia
Surgical
DVT
procedure
PE
minor
2%
0.2%
General
Neuro
Uro/gyn
20%
30%
40%
2-3%
Hip
Knee
Spine
Trauma
50%
60%
60%
60%
5%
Risk of bleeding
P Bleeding d/o
P Use of antiplatelet meds
P Previous GI bleed
P Cancer
P Hepatic/renal insufficiency
P ?age
VTE prophylaxis: what’s
available?
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Intermittent compression devise
Stockings
ASA 80-325 mg
UF heparin 5000 bid, tid
LMW bid
Warfarin
Anti – Xa pentasaccharide (fondaparinix)
Efficacy of mechanical VTE
prophylaxis
Mode
↧ VTE
↥bleeding
Stockings
IPC boots
IVC filter
50-60%
50-60%
↧PE,↥DVT
None
None
Procedure related
Early ambulation
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Routine for all pts
Acceptable as sole mode for low risk
Useful adjunct esp post knee/hip
surgery
Elastic stockings
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First shown to work in 1952
Decrease venous pooling
Evidence of benefit for mod/high risk,
but used only as adjunct
Harmful if not work correctly
ICD
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Work very well
Not useful form BMI >25
Only effective if used correctly and
continuously when pt not ambulating
Have potential to reduce ambulation
Recommended in mod-high risk gyn surgery
as solo
Not recommended as sole mode in
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Highest risk – except neurosurgery
High risk urological
Hip and knee surgery
IVC
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For absolute contraindication of
anticoagulation
For life-threatening hem on AC
For failure of AC
Used to prevent fatal PE
Temporary filters preferred
If left in place, cause DVTs
Efficacy of pharmacological
VTE prophylaxis
mode
↧ VTE
↥bleeding
ASA
UF heparin
LMW heparin
Warfarin
0-50%
40-75%
50-75%
20-60%
50%
60-70%
50-100%
<10%
Aspirin
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Not recommended as sole prophylaxis
Beneficial post hip-fracture
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160 mg OD, 5/52, 13,000 pts
Combined with routine prophylaxis
PE – 0.7 vs 1.2
Fatal PE 18 vs 43
UF heparin
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Good for moderate risk gen surgery
Modest increase in bleeding
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Compared to LMWH (2.65% vs 1.8%)
Additive effect of stockings and ICD]
Risk of HIT
warfarin
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For very high risk with lower extremity
orthopedic and neuro surgery
For gen surgery other methods work just as
well…
Good for extended prophylaxis
Delayed onset of action, may start preop!
Recommended for
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Hip #, THA, TKA
LMW heparin and
Pentasaccharideds
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Preferential inhibition of factor Xa
FDA approved for DVT prophylaxis
Not FDA approved as of yet for DVT
prophylaxis in pregnancy, spinal cord
injury, trauma, neurosurgery… but are
being used
LMW heparin and
Pentasaccharideds cont’d
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Effective for mod risk general surgery
Gyn/obs
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Trauma
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second line to mechanical
Method of choice only if risk of bleeding is not
significant. If it is – stocking+/-ICD
Recommended for ortho lower extremity
surgery
Fondoparinix reduces asymptomatic DVTs
only…
LMW heparin and
Pentasaccharideds cont’d
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Risk of epidural hematoma
Strategies
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Avoid regional anesth in those prone to bleed
Needle in 12 h after onset of LMWH
Single dose anesthetic better then infusion
D/c cath in 12 h
No dosing of LMWH within 2 h of cath d/c
Direct thrombin inhibitors
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Effective in initial studies
Comparable to LMWH
For HIT pts
Duration of prophylaxis
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Start immediately after or prior to surgery
7-10 days post
Warfarin may be started 10/7 prior but INR
should be less then 1.5
Argument for prolonged (30 day) prophylaxis
for high risk. DVT incidence
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sympt – 3% vs 1% on treatment
Asympt – 19% vs 9% on treatment
Prolonged prophylaxis
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Orthopedics
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Post THA for 4-6 weeks with LMWH or
warfarin, especially with Risk Factors
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Obesity, sedentary, prior DVT
General surgery
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Prolonged treatement with LMWH prevents
out-pt DVTs but at a marginal cost that
was deemed inappropriate
Screening for DVT?
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Not in the asymptomatic pts….
Diagnostic strategy of DVT
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Suspect
Dupplex
For proximal or ANY symptomatic –
treat
For distal AND asymptomatic – follow
with serial duplex US
Accuracy of Tests for
Diagnosis of PE
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Clinical suspicion is paramount
test
sensitivity
specificity
High Prob
VQ
Spiral CT
41%
97%
91%
93%
D-Dimer
90-100%
25-60%
Diagnostic strategy for PE
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Suspect
VQ
If normal AND D-Dimer low – ruled out
If high probability – start treatment
If indeterminate/nondiagnostic – angio,
angio CT
Treatment
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IV heparin, aPTT 1.5- 2.3 normal 5/7
May use LMW
Coumadin INR 2-3
Overlap heparin and warfarin 4/7
On warfarin 3-6/12
Consider ECHO/trop to evaluate RVF for
PE to id High Risk pts.
Treatment
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Hemodynamically unstable PE may
require pressure support, fluid status
monitoring, and/or thromolysis /
surgery
Cases to consider
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38 yom for elective IHR
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65 yom for elective IHR
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None, low risk
Moderate risk, Consider UN heparin pre-op, ambulation,
stockings post op
50 yom, obesity/CHF/prev DVT for IHR
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High risk, consider LMWH preop/post op. Conisder
warfarin
Cases concluded
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25 yof post severe head injury
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25 yom post trauma/abdo/chest
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High risk, mechanical initially, consider LMWH when risk of
bleeding is low
75 yof post hip #
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High risk, mechanical,
High, consider LMWH periop, warfarin or aspirin post op
65 yom post THA, obese
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High, consider LMWH periop, warfarin or aspirin post op