Deep vein thrombosis is the formation of a blood clot in one of
the deep veins of the body, usually in the leg
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History
Susruta (Ayurveda physician and surgeon, 600-1000B.C), Patients with a
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"swollen and painful leg that was difficult to treat"
First description of pulmonary embolism by Giovani Battista Morgagni in
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1761, described large blood clots in the pulmonary vessels of patients whodied suddenly
History
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"Discovered" PE in 1846 ? "the detachment of larger or smallerfragments from the end of a softening thrombus which are carried
along the current of blood and driven into remote vessels.
This gives rise to the very frequent process on which I have
bestowed the name Embolia
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In 1856, Rudolf Virchow published a collection
titled "Collective Treatises on Scientific Medicine,"
which contained his detailed studies of embolization
following venous thrombosis.
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Virchow's triadNeurologically impaired patients-
moderate to high risk for VTE
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Paresis/Paralysis Venous stasisProlonged duration of depressed consciousness/coma
Brain neoplasm/Rheumatological/inflammatory disorders Hypercoagulability
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Prolonged duration of surgery
Aneurysmal SAH ? Vessel injury/ Endothelial activation
DVT in neurologically impaired patients
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Large variation in the statistics- overall incidence of DVT
Incidence of DVT ranges from 21-34%- among pts who underwent cranial or
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spinal surgeries without any DVT prophylaxisHigher incidence seen (~50%)- in pts with spinal cord injury and ischemic
stroke
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Incidence of DVT in aneurysmal SAH is 1.5-24%
Symptomatic deep vein thrombosis is
"tip of the iceberg"
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The presence or absence of clinical symptoms of DVT is as unreliablemarker
Signs and symptoms of DVT
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Pain or tenderness in the leg
Swelling of the leg or along a vein in the leg
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Red or discoloured skin on the legIncreased warmth in the area of the leg that's swollen or is in pain
Homan;s sign- pain in posterior calf with forced dorsiflexion of foot
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Moses sign- gentle squeezing of the lower part of calf from side to side causes severe pain
Diagnosis of DVT
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D- Dimer Assay125-labelled fibrinogen test
Impedance plethysmography
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Doppler ultrasound of femoral veins
Venography
DVT risk assessment score
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DVT prophylaxis methods
Graduated
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Pharmacologicalcompression
Neuromuscular
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prophylaxis
stockings
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electrical stimulationMechanical
Methods
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UFH
LMWH Warfarin
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Intermittentpneumatic
Venous foot pump
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compression
DVT prophylaxis methods
Early and frequent ambulation- historically used to prevent DVT
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Not feasible for critically ill, neurologically impaired patients
Largest no. of thromboembolic events occurred after pts started to ambulate
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Ambulation ?counteracts only one component of Virchow;s triad- venous stasisMechanical methods
Graduated compression stockings:
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Graded circumferential pressure from distal to periphery
Greatest degree of compression at the ankle, with the level of compression gradually
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decreasing up the garmentPressure gradient ensures, blood moves from limb towards heart
Reduces diameter of veins
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Improves venous flow velocity
Avoid venous stasis
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Less efficacious in immobile patientsIn CLOTS trial 1, symptomatic and asymptomatic deep vein thrombosis
occurred in 126 (10.0%) patients wearing graduated compression stockings
and in 133 (10.5%) not wearing them, for a nonsignificant absolute
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reduction in risk of 0.5% (95% confidence interval [CI] ?1.9% to 2.9%).Intermittent pneumatic compression:
Cycles of compression and relaxation of pumped air
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Inflates first at ankle with higher pressure
Inflates last at thigh at lower pressure
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Deep veins are compressed and displaces blood proximallyVein refill from distal flow when cuff deflates
Simulating pulsatile blood flow
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Useful as a solo measure in neurosurgical patients where anticoagulants are to be avoided
LIMITATIONS: Improper fitting/neurovascular compression/iatrogenic DVT
CLOTS-3 trial, concluded that with the use of thigh length sequential IPC, in
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patients with acute stroke leads to signifcant reduction in the
development of DVT.
Venous foot pump:
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An alternate to IPC/compression stockings
Higher compression force
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Neuromuscular electrical stimulation:Muscle contractions decrease stasis improve venous return
Comatose/neurologically impaired patient unable to contract muscle
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Deliver pulses of electric current, via electrode on skin over selected muscle groups or
nerves to induce involuntary contractions
Pharmacological methods
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Low dose unfrationed heparin (LDUH)- S/C heparin 5,000 IU 8 Hourly (high risk)or 12 hourly
(moderate risk)
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Low molecular weight heparin (LMWH)- e.g. S/C enoxaparin 40mg daily when creatinineclearance > 30ml/min or 30mg daily when creatinine clearance <30ml/min
Warfarin- high risk patient to keep INR between 2-3
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Newer antithrombotic drugs
Agent
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MOA/RADuration of action
fondaparinaux
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Factor Xa inhibitor /S.C
36-48hr
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RivaroxabanDirect factor Xa inhibitor/oral
2-3 day
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Apixaban
Direct factor Xa inhibitor/oral
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2-3 dayEdoxaban
Direct factor Xa inhibitor/oral
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One day
Dabigatran
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Direct thrombin factor/oral2-3 day
Desirudin
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Direct thrombin factor/oral
7-9 hrs
VTE prophylaxis for the patient who
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underwent craniotomyACS-NSQIP data (2011-2012)- 10477craniotomy patients- VTE-3.2%
Smith et al-1148 patient who underwent craniotomy for brain neoplasm,
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incidence of DVT- 14% and PE 3%
Risk factors for postoperative venous thromboembolism in neurosurgery
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Its recommended to use IPC+LMWH or IPC+UFH after 24-48 hr followingcraniotomy to minimize risk of VTE
Intracranial bleeding occurs in approximately 1-1.5% of craniotomy patients who
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do not receive anticoagulant prophylaxis
The use of anticoagulant thromboprophylaxis may be associated with a small
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increase in the risk of intracranial; haemorrhageThe timing of initiation of anticoagulant thromboprophylaxis appears to
influence postoperative bleeding risk
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Bleeding risk higher in the patients where prophylaxis given prior or soon after the
craniotomy as compared to when administered after 24 hrs
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Decision should be made based on patient's bleeding and thrombosis riskVTE prophylaxis for patients with
aneurysmal SAH
Patients with a SAH are at increased risk of developing VTE,
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Incidence of DVT ranges from 1.5 to 24% and the incidence of PE 1.2-2.0%
Worse clinical status at presentation, longer hospital stay and blood transfusion are
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associated with higher risk of VTE in this patient populationDetermining appropriate VTE pharmacoprophylaxis is challenging in presence acute bleed
Initiating IPC as VTE prophylaxis as soon as patient with aSAH is admitted
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Initiating VTE prophylaxis with UFH at least after 24 hr after aneurysm has been clipped or
coiled.
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LMWH has shown higher risk of bleeding in this patient groupVTE prophylaxis for patients with
traumatic brain injury (TBI)
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Incidence of DVT in severe TBI patient ranges 13 to 17%Initiating IPC within 24hrs of presentation of TBI or completion of craniotomy
Initiating LMWH or UFH after 24-48 hr of presentation with TBI and ICH
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LMWH OR LDUH in combination of mechanical prophylaxis may be used however there
is increased risk of expansion of intracranial hemorrhage (Level-III evidence, BTF 2016)
Parkland's protocol
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VTE prophylaxis for patient with spinal cord
injury
Spinal cord injury- independent risk factor for DVT
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Reported incidences of DVT in paralytic spinal cord injuries ranges from 18 % to 100% within first
12 weeks of injury
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Risk of DVT highest during first 2 weeks post injuryInitiating VTE prophylaxis as early as possible within 72hrs of injury or once bleeding is controlled
Mechanical prophylaxis alone in not enough
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LMWH or LDUH with or without IPC is recommended
VTE prophylaxis for the patient who
underwent spinal surgeries
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Generally at lower risk for VTEIncidence ranges from 0.4% to 1.1%
Higher risk seen in patient with associated carcinoma, limited preoperative
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/postoperative mobility, complex or multilevel and prolonged procedure and
advanced age
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Almost 50% of thromboembolic events in spinal surgery occur after hospitaldischarge
Early mobilization
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Inhospital thromboprophylaxis startring with IPC followed by delayed use of
LMWH (after 24 hr)
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Reported rates of epidural hematoma associated with thromboprophylaxis isvery low (~0.2%)
VTE prophylaxis in critically ill patients
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with ischemic strokePulmonary embolism accounts for 10% of deaths in AIS patients
With thromboprophylaxis there is concern of haemorrhagic transformation of
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ischemic stroke
Various randomised trials and metaanalysis are in favour pharmacological
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thromboprophylaxisVTE prophylaxis should be started as soon as possible
Patients with AIS with restricted mobility, LMWH in combination with IPC
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Stroke patients who undergo hemicraniotomy or endovascular procedure,
UFH/LMWH and/or IPC should be used in the immediate postsurgical epoch,
except when r TPA is administered, in that case it should be delayed for 24hr
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VTE prophylaxis in critically ill patientwith intracranial haemorrhage
In few prospective studies incidence of DVT detected by venous
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ultrasonography was 20-40%Risk of VTE in patients with ICH has been estimated 2-4 times as high as
patients with AIS
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Its recommended to use IPC/GCS over no prophylaxis at the time of
hospital admission
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Using LDUH/LMWH to prevent VTE in patients with stable hematomawithout ongoing coagulopathy, after 48 h of admission
Mechanical prophylaxis can be continued once pharmacological
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prophylaxis started
VTE prophylaxis in critically ill patients
with neuromuscular disease
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Patients who are critically ill with neuromuscular diseases like GBS, MG are
at high risk of VTE
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VTE prophylaxis is the key element of the care of these patientsLMWH or LDUH or Fondaparinaux as the preferred method of VTE
prophylaxis
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Mechanical prophylaxis where risk of bleeding is significant
VTE prophylaxis should be continued for extended period, at a minimum
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for th eduration of acute hospitalization or until the ability to ambulatereturns
VTE prophylaxis in critically ill patient
with intracranial haemorrhage
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In few prospective studies incidence of DVT detected by venousultrasonography was 20-40%
Risk of VTE in patients with ICH has been estimated 2-4 times as high as
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patients with AIS
Its recommended to use IPC/GCS over no prophylaxis at the time of
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hospital admissionUsing LDUH/LMWH to prevent VTE in patients with stable hematoma
without ongoing coagulopathy, after 48 h of admission
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Mechanical prophylaxis can be continued once pharmacological
prophylaxis started
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