venous thromboembolism Flashcards
virchow’s triad for why blood clots when it shouldn’t
- activation of coag
- venous stasis
- injury to vessel wall
2 main types of VTEs
- PE
- DVT
- same disease, different course
most common location of DVT
legs»»arms
3 classes of DVT
- proximal - pop>iliac>IVC - 90% of PEs
- distal/calf - below knee - rarely PE
- superficial - not a DVT, never PE
what is key component leading to PE
proximal DVT
what is epi of VTE
- age dep.
- most common preventable cause of death in hosp.
**9 acute risk factors for VTE
- major surg.
- trauma
- CA
- CA treatments
- immobilization
- acute medical illness
- acute infection
- inflammation
- E, preg, post-partum
5 other risk factors for VTE
- previous VTE
- fam Hx
- inherited
- age
- obesity
where are most VTE aquired
hospital
3 major risk surgeries
- spinal cord
- trauma
- ortho
how long is VTE risk for
up to 12 weeks out of hospital
what is role of immobilozation
alone not a factor, but in combination with other factors
what is relation to CA
25x in CA
- often first manifestation of CA
3 E related risks for VTE
- OCP - 4x
- HRT - 4X
- preg
why does a VTE develop
generally multifactorial with a number of factors
S and Sx of DVT (4)
- leg swelling
- leg pain
- warmth
- purple-blue colot
many have no Sx
S and Sx of PE
- SOB
- chest pain
- desaturation
- tachycard
- unexplained fever
- blood in sputum
- feeling faint
investigations for VTE
D-dimer - not a very good test
DVT - doppler US
PE - CXR
what is d-dimer
formed by plasmin effect on fibrin
- increased in VTE
what is seen on doppler
can’t collapse the vein
3 tests for PE
- CT pulm angio
- look for DVTs
- V/Q scan - rules out PE if perfusion normal
4 possible treatments
- IV heparin
- LMWH
- oral warfarin
- directo oral anticoags
MOA, adv. and dis of IV hep
MOA: - inhibs factors 2, 10, 9, 11, 12 adv: - good control of coag cascade - rapidly reversed dis: - IV -in patient - frequent PTT tests - possible HIT
MOA, adv. and dis of LMWH
MOA: - inhibs factor 10 and 2 adv: - sub-cut - predictable - can vary dose dis: - needle phobia - renal accum - costly
MOA, adv. and dis of IV warfarin
MOA: - inhib vit K factors: 10, 9, 7, 2 adv: - 60 years - not renal - labmonitoring - cheap dis - lab monitoriing - unpredictable - 50 fold varitation in dose
MOA, adv. and dis of direct oral anti-coag
MOA - 10a or 2a inhibs adv - fixed dose - few interaction - no labs dis - uncertain doses - renal accum - cost
3 basic VTE treatment options
- LMWH q1d for 5-7 days, + warfarin
- LMWH q1d for fll time
- direct oral anti-coag
2 clot reduction therapies for massive PE
- cath. endo therapy
2. tPA
therapy for massive DVT
tPA
how long for anti-coag
3 months + continue if at risk of recurrence (unprovoked, active factors)
what is natural VTE history
slowly go away
3 outcomes
- recur in 30%
- post-thrombotic syndrome - 20-50%
- chronic pulm hypertension - 2-5%
