coagulation cascade — damage: TF release that activates cascade—— prothrombin—- thrombin - thrombin cleaves fibrinogen to fibrin stabilize clots

VTE Patho + Prophylaxis Flashcards by Alanna Parker

3 Fxns of endothelial in BVs

1) barrier: hide shit in sub-endo
2) Antithrombotic + antiplatelet secretions
3) Fibrinolytic secretions

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Primary Hemostasis

Platelet aggregation + activation
- damage to BV— collagen + vWF —- bind to cells + activate —- release serotonin, thromboxane A2, ADP—- binds to IIa/IIb receptors === activation of platelets + conformation change
— can bind to fibrinogen to clump together

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Secondary hemostasis

coagulation cascade
— damage: TF release that activates cascade—— prothrombin—- thrombin

thrombin cleaves fibrinogen to fibrin

stabilize clots

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What is the 3 fxns of thrombin

1) cleave fibrinogen to fibrin
2) recruit + activate platelets
3) increase thrombin release (+ feedback)

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What are some examples of inhibitors of coagulation

antithrombin , heparin, Protein C + S

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What is thrombosis

process that occurs with inappropriate or over-activation of hemostasis in an not injured or slightly injured BV

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Arterial thrombus vs venous thrombus

Arterial: results from ruptured plaque (atherosclerotic) in arteries —- causes MI, stroke, PAD

Venous: forms from slowing /decrease BF in venous system —- DVT or PE (normally result of trauma or surgery)

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T or F: most PEs start from thrombus formed in deep veins of legs that travel to LS of heart + go to lungs

F- RS of heart

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Why do DVTs and PEs not cause HAs

—- clots that form in venous system ; they gets stuck in lungs before getting into the LS of the heart + impact BF to the heart itself

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Which type of DVT have a higher risk of thrombus embolization

Deep veins —- specifically we care more about the proximal ones (closer to the lungs)
—- aka anything about the knee—-scary

Superficial ones: smaller + closer to surface

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T or F: VTEs are the 2nd most common cause of CVD in Canada

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T or F: 1/3 of people with VTE will get recurrent episodes

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T or F: 50% of VTEs occur in pts without RFs

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What is Virchow’s triad

Stasis of BF: slow turbulent BF (not laminar)
— increase conc of shit near BV surface + increase change of interaction

Hypercoagulability: more likely to clot

BV injury : activation of primary + secondary hemostasis

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What are conditions that increase clotting risk (hypercoagulability)

Protein C or S deficiency
Prothrombin gene mutation
Anthiphospholipid Ab
Antithrombin deficiency
Factor V Leiden
Pregnancy
Estrogen therapy
Malignancy

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What are Strong RF of VTE

fracture of hip or leg
hip or knee surgery
major trauma /surgery
SC injury

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Moderate RF of VTE

Chemo
HF
RF
pregnancy (postpartum)
previous VTE
malignancy
hormone replacement therapy
thrombophilia

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Weak RF of VTE

bed rest > 3 days
immobility for LT (prolonged travel)
age
obesity
pregnancy
varicose veins

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SS of DVT

unilateral swelling, pain, cramping, warm

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T or F: if have DVT/PE, you may have elevated D dimer

T- D dimer is breakdown product of fibrin

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SS of PE

cough, chest tightness, SoB, dizzy, palpitations, tachypnea, tachycardia, hypoxemia, fever, distended neck veins

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What is the Wells Criteria

Study These Flashcards

Scoring system to determine what type of test to use
—- gives risk of VTE —- and what to do for there

If pt low risk of VTE based on Well’s criteria, what test do we do

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D dimer test
—- high sensitivity but low specificity
—- good at ruling OUT (if - : don’t have VTE)

If pt moderate to high risk of VTE based on wells criteria, what do we do next

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Use more specific testing

DVT: compression ultrasonography

PE
- spiral CT: use more often (use X rays to look into body)
- ventilation perfusion scan : give radioactive shit to see if mismatch bw ventilation + perfusion around body

How does compression ultrasonography work

apply transducer behind leg + groin — healthy vein: when apply P will collapse - if DVT: won’t collapse with pressure

T or F: in distal DVTs, 3/4 will stay below knee + dissolve themselves

T - 1/4 will go proximal + cause symptoms (don’t treat until now) ** most symptomatic DVTs start here

T or F: 50 of symptomatic DVTS will cuase PE within 3 mths

T —- why we treat (increase PE risk)

What is one of the most common complications in pt after having a DVT

PTS - 20-50% get — leftover shit after clot dissolves /leftover BV damage —- impaired BF still

SS of PTS

pain, heaviness, swelling, itching or tingling of leg —- can come + go

Is there a treatment for PTS

NO — best option is to prevent DVT — compression stockings can help with symptoms

____ % of symptomatic cases of PE are fatal within hour of symptom onset

10%

_____% of people with symptomatic PE die within year of diagnosis

25% — highest risk in 1st mth

What is chronic thromboembolic pulmonary HTN

1-3% get this complication after surviving PE —- leftover shit from PE causes increase in P in RV—- enlarges—- RS HF

What is the risk of recurrence of provoked VTE after finishing 3 mths of treatment

1-3% year

Risk of recurrence for unprovoked VTE after 3 mth therapy

10%

___% of VTE occur due to hospital

60%: current hospitalization or hospitalization in previous 6 wks —- PEs are one of the most common preventable hospital related deaths

what percentage of fatal PEs occur in non-surgical pts

70-80%

Anticoagulation prophylaxis can reduce VTE incidence by ____ %

What are the 2 approaches for VTE prophylaxis therapy

1) individual base: estimate risk of VTE, bleed etc for each pt 2) group based: standardized set of orders for all pts within one set group/service —— easier + systematic (requires every MD to think about risk for that pt when admitted) —- disadvantage: may lead to over treatment of low risk pt

Methods to estimate VTE risk

1) Statistically validated risk tool (modified Caprini model): use different points for different RF to give general score + then interpret score —- risk 2) Clinical gestalt/pattern recognition: HCP recognize set traits that influence risk + use their knowledge /experience to determine what to do

What is defined as major bleeding

fatal bleeding, symptomatic bleeding into critical care, or bleeding that causes drop in Hg by 20g/L or requires 2 units of blood

T or F: there is a set score we can use to determine bleeding risk

F—- no set score, have to look at CI and relative risks of bleeding etc

Absolute CI of anticoagulation

active clinically important bleed, platelets < 30 x 10^9 and major bleeding disorder

relative CI to anticoagulation

intracranial bleeding past 3 mths, recent perispinal bleed, recent high bleeding risk surgery (cardiac, spinal ,trauma)

General treatment approach for prophylaxis in pt with absolute CI + most relative CI to anticoagulation

mechanical (IPC or GCS) — some relative CI with high VTE risk : get a specialized team in

T or F: everyone should be encouraged to have early + frequent ambulation to prevent VTE

What is IPC

Intermittent pneumatic compression: put these things on your calves/full legs — inflate + deflate to improve venous return/ BF — Harms: discomfort, skin breakage, nerve damage (rare) — avoid if PAD or leg ulcers

What are GCS

graduated compression stockings - calf or thigh highs — evidence to help with DVT (no PE) harms — similarly to IPC, likely to worsen arterial BF in those with PAD

What are the general therapeutic options for VTE prophylaxis

UFH, LMWH, Fonda

What is our go to option for VTE prophylaxis

LMWH unless CrCl< 30 OR HIT history OR Cost issue

Duration of VTE prophylaxis

Generally until hospital discharge (NOT ONCE START MOVING) — can consider LT therapy up to 30 days after discharge if pt had major abdominal pelvic cancer surgery

T or F: People in LTC homes are at an increased risk of VTE due to immobility and would benefit from VTE prophylaxis

F- increase risk but don’t treat

Preferred prophylaxis treatment for cancer pts

LMWH, apixaban or riva — only give it high risk + no RF for bleeds/CI

What is the recommendations for VTE prophylaxis in high risk pt undergoing long distance travelling (> 4 hours)

LMWH or GCS (preferred) — high risk: recent surgery, postpartum, active malignancy

VTE Patho + Prophylaxis Flashcards

(54 cards)