IC4&5 Flashcards
what are the three factors in the Virchows triad
1) hypercoagulability = blood
2) circulatory stasis = flow
3) vascular damage = vessel
what are the risk factors for hypercoagulability?
- major trauma or surgery
- pregnancy post partum
- IBD
- sepsis or infection
- autoimmunity
- malignancy
- dehydration
- inflmamation
- estrogen drug therapy
- antiphospholipid syndrome
what are the risk factors for circulatory stasis?
- varicose veins
- bradycardia or hypotension
- obstruction of venous flow = obesity, pregnancy, tumors
- immobility
what are the risk factors for vascular damage?
- atherosclerosis
- cellulitis
- venous catheter
- heart valves
- physical trauma, strain, injury
what are the other risk factors for VTE?
age (older = more risk, esp if >75y/o)
prior history to VTE.
what are the symptoms of DVT?
UNILATERAL LL swelling, redness, pain.
what are the signs of DVT
1) pain behind the knee upon dorsiflexion of feet of affected limb
2) dilated superficial veins of the affected limb
what are the symptoms of PE? state the reasons for these symptoms
1) SOB, palpitations, cough, chest pain, chest tightness.
2) hemoptysis
3) dizzy, lightheaded
embolism/clot flows to the vessels at the lungs, obstructing blood flow. this reduces gaseous exchange and transport of o2 to the other parts of the body = may result in circulatory collapse.
what are the signs of PE?
1) dilated neck veins
2) tachypnoea, tachycardia, diaphoretic
3) hypotension, cyanotic, LOW SPO2
4) possible cardiogenic shock leading to death
differential diagnosis of DVT?
1) cellulitis = also presents with erythema and pain
2) lymph odema, fluid retention = may present with swelling.
what are the signs of hemodynamic instability in PE?
1) cardiac arrest
2) obstructive shock
- systolic bp <90mmhg or require vasopressors to >90mmhg
- end organ failure: cold clammy skin, altered mental status, oliguria/anuria
3) persistent hypotension
- systolic bp <90mmhg or drop of >40mmhg (last more than15min).
differential diagnosis for PE?
myocardial infarction, angina?
other classification for high-risk PE?
RV dysfunction on tte/ctpa and elevated troponin levels
pesi class iii-iv (includes age, hx of hf, cancer, chronic lung disease, hr, altered mental status, bp, rr, temp… etc)
what is the wells DVT scoring
1) active cancer
2) bedridden >3 days, major surgery last 4 weeks
3) calf diff >3cm
4) entire leg swollen
5) collateral superficial veins (non-varicose)
6) pitting edema
7) localised tenderness distributed across the deep venous system
8) paralysis or immobility of the lower limb
9) diff diagnosis that exclude = -2
more than 2 than send for imaging (CUS, compression ultrasound)
what is the PE wells scoring
1) s/sx of DVT = 3pt
2) other diff diagnosis unlikely = 3pt
3) malignancy = 1pt
4) hemoptysis = 1pt
5) bedridden >3 days, major surgent last 4 wks = 1.5 pts
6) HR >100 = 1.5pts
7) previous vte/pe = 1.5pts
if >4 points = likely diagnosis for PE = send for CTPA/VQscan.
treatment algorithm for PE (high or mod risk)
if high risk:
- initiate either bolus UFH or thrombolytic therapy = weight risk vs benefit
- UFH recommended due to shorter half life = less bleeding risk esp for hemodynamically unstable patients.
- if thrombolytic therapy c/i, consider surgical pulmonary embelectomy.
if mid-low risk
- if parenteral, recommend LMWH eg enoxaparin over UFH.
- parenteral recommended due to faster onset and reliability while hospitalised (nurse administration)
if oral, recommend DOACs over VKA.
recommendation for treatment is 3 months
when to extend therapy for dvt/pe longer than 3 months
if unprovoked vte
check patient adherence
renal and hepatic impairment
weigh bleeding risk vs benefit of permanent/long term treatment
at least yearly monitoring is required eg rechecked bleeding risk
FYI conditions include medically ill eg sepsis and major surgery eg THR/TKR.
when is VKA recommended over DOACs for DVT PE
antiphospholipid syndrome
- should be on indefinite treatment with VKA eg warfarin
left ventricular thrombus
if patient has severe renal impairment crcl <30
- unable to use DOACs
- must be combined with UFH/LMWH that is dose adjusted for severe renal impairment
what happens if patient has active bleeding or current contraindication to anticoagulants
initiate on IVC (inferior vena cava; used to prevent the clot from travelling to lungs) filter first and start anticoagulants once bleeding is stopped or contraindication is resolved.
when to consider LMWH monotherapy
1) active cancer
- treat for 6 months then reassess
2) liver disease and coagulopathy
- warfarin not suitable as iNR may not reflect antithrombotic effect.
3) pregnancy
- vka contraindicated in first trimester
- doacs not well studied
what are the treatment algorithms for DVT
1) apixaban 10mg BD x 7 days > 5mg BD > 2.5mg BD
2) rivaroxaban 15mg BD x21 days > 20mg OM > 10mg OM
3) LMWH/UFH/fondaparinux x 5days then either dabigatran 150mg BD or edoxaban 60mg OD
4) LMWH/UFH/fondaparinux + PO warfarin for atleast 5 days and INR>2 (for 2 readings or 2 days in a row) THEN warfarin dose adjusted to maintain INR 2-3.
edoxaban VTEP dose and dose modification?
60mg PO OD
if crcl 30-50 or BW <60kg
= 30mg/day
compare the renal clearance of the DOACs
A < R < E < D
25 33 50 80
compare the metabolism of DOACs
edoxaban is minimally hepatic, (<4% by 3a4)
dabigatran is metabolised by plasma esterases (also minimally hepatic, 80% excreted unchanged as urine)
rivaroxaban (also 2j2) and apixaban undergo cyp3a4 metabolism
ALL are affected by PGP transporters.
(VTE) what is the renal adjustment for dabigatran?
crcl <50 and concomitant pop inhibitors
= avoid
(VTE) what is the renal adjustment for apixaban?
15-29 caution
hd AVOID
(VTE) what is the renal adjustment for rivaroxaban?
<30 avoid
(VTE) what is the renal adjustment for edoxaban?
> 95 = not recommended
difference between the moa of the 4 doacs
only dabigatran is a direct factor iia antagonist, other three are direct factor xa inhibitors
what is the vtep dosing for dabigatran?
hemostasis achieved, start within 1-4h post surgery
TKR: 220mg/day x 10 days
THR: 220mg/day x 28-35days
if crcl30-50, caution, reduce to 150mg/day
what is the vtep dosing for rivaroxaban?
hemostasis achieved, start within 6-10h post surgery
TKR: 10mg/day x 2 weeks
THR: 10mg/day x 5 weeks
if medically ill, reduce dose to 10mg/day for up to 31-39 days
what is the vtep dosing for apixaban?
hemostasis achieved, start within 12-24h post surgery
TKR: 25mg BD x 10-14 days
THR: 25mg BD x 32-35days