Therapeutics - VTE (Hughes) Flashcards
define DVT (deep vein thrombosis)
blood clot in 1 of large veins (usually in les of arm)
can partly or completely block flow of blood thru the vein
if DVT is not treated, what can happen
it can move or break off into the lungs, causing a pulmonary embolism - can die from it
thrombus vs embolus
thrombus - clot that stays in blood vessels
embolus - when clot breaks off and travels to another part of the body
what is “virchow’s triad”
risk factors for thrombo embolism
stasis
vessel wall injury
hypercoaguability
clotting factors form a clot in a __
vein
why are clots typically in veins and not arteries?
lot less pressure in veins
primary complication of DVT
PE
DVT and PE are a concern after….
hip and knee replacements
there is a reimbursement penalty from medicare if the pt gets one
NEED PROPHYLAXIS
factor II vs IIa
II - prothrombin
IIa- thrombin
name some clotting inhibitors
antithrombin
protein C and protein S
plasminogen
plasmin
factor I and Ia
I - fibrinogen
Ia - fibrin
are antiplatelets used to treat DVT
NO - used for ARTERY clots
for vein thrombi — anti coagulation factors (anticoagulants)
true or false
if someone has high levels of proteinC and proteinS, there are less likely to get blood clots
TRUE
these prevent blood from clotting too much
a deficiency is called “hypercoagulability
surfaces that contact the blood can cause clotting
name 2
catheters, a tumor
RAMS
risk assessment models for clots
symptoms of pulmonary embolism
fast breathing and heart rate, pain when breathing cough
name a specific drug that is a risk factor for clots
estrogen
symptoms of deep vein thrombosis
leg swelling (1 side), heat, pain, tenderness
but lot of clots are asymptomatic!
tests for DVT
D-dimer (blood test) tells us if there’s fragments of a clot
GOLD STANDARD is duplex/doppler ultrasound
true or false
patients with deep vein thrombosis are always treated inpatient
FALSE - can be treated outpatient
true or false
PE’s are generally treated as inpatient
TRUE
gold standard for diagnosing PE
CT angiography
but bad thing is you need contrast dye – may have SE and potential allergic reaction
_____ should be evaluated for the risk of VTE
every hospitalized patient
nonpharmacologic ways to prevent VTE
graduated compression stockings (move leg around), leg exercises
NOT VERY EFFECTIVE - “may” work
when may a patient only be given nonpharm prophylaxis for VTE
when bleeding risk is too high
true or false
pharmacologic prophylaxis for VTE is generally very effective
TRUE
guideline recommendation for acutely medically ill patient for VTE prophylaxis
-pharmacologic better than mechanical prophylaxis over no parenteral
according to the guidelines, which pharmacologic class is recommended for VTE prophylaxis
LMWH is recommended over DOAC
(unless there’s some reason you can’t use a LMWH - then u may use a doac)
name 3 LMWH
enoxaparin (lovenox)
dalteparin (fragmin)
tinzaparin (INNOHEP)
name 4 DOACs
eliquis (apixaban)
xarelto (rivaroxaban)
dabigatran (pradaxa)
edoxaban (savaysa)
heparin can be used for prophylaxis of VTE
what does this mean
any safety concern?
LOW DOSE unfractionated heparin
5,000 units SUBQ Q8-12 HOURS
it’s available as lot of diff concentrations - so have to be very careful
disadvantage of LMWH vs low dose unfrac. heparin for VTE prophylaxis
more expensive per dose
dosing of lovenox for VTE prophylaxis
what about if crcl less than 30mL/min?
normal - 30mg SUBQ Q12 OR 40mg SUBQ QD
CrCl less than 30 - 30mg SUBQ QD
dosing of fragmin (dalteparin) for VTE prophylaxis
2500-5000 units subq QD
true or false
fondaparinux cannot be used for VTE prophylaxis
FALSE - it can, just not in CrCl less than 30 or if they weigh less than 50kg
dose of fondaparinux for VTE prophylaxis
2.5mg subq qd (as prefilled syringe)
ONLY doac indicated for generally medically ill patients for VTE prevention
rivaroxaban
10mg PO QD 31-39 days
which DOAC is LEAST dependent on the kidneys for elimination
apixaban!
no dose adjustment necessary
can edoxaban be used for prophylaxis of VTE
NO - not approved
can warfarin be used for VTE prophylaxis
if so, what is goal INR
YES - for hip or knee replacement surgery
goal INR is 2-3
3 general indications in which we can use DOACs for VTE prevention
-exented prevention for recurrent VTE
-acut medically ill (only xarelto)
-post op for hip/knee replacement (MAIN(
true or false
xarelto must be taken with meals
false - doesnt matter
route administration dabigatran
PO
frequency xarelto and eliquis and dabigatran
xarelto - QD
eliquis - BID
dabigatran - QD
monitoring for VTE prevention therapy:
they do not affect any coagulation labs - not reason to check them
except warfarin - need to monitor INR
just monitor for signs of bleeding, and make sure it’s working by pt not getting clot!
as mentioned, for VTE prophylaxis, we do not need to monitor for signs of efficacy. however,,,
we need to monitor for toxicity
what number is “normal” INR?
what is goal INR for warfarin?
1 is normal
for warfarin - 2.5 – range of 2-3
may need higher to have efficacy in certain conditions like mitral valve replacement
formula for INR
PT (prothrombin time) of patient /PT of reference plasma
the lab value of anti-xa activity can be used to monitor the extent of antithrombitic effect for………..
is it done routeinely?
LMWH’s
not done routinely - only in obesity or pregnancy
which drug do we monitor APTT
heparin, and ONLY for the treatment dosing - not the low dose for prevention
true or false
aPTT is not standardized across all labs
true
each lab must calibrate – have nomograms to achieve
true or false
INR is used for warfarin only
TRUE
aPTT monitoring is used for ___ and ____ ONLY
heparin and IV thrombin inhibitors
thrombolytics, went used for treatment of VTE, are given how often?
only once
3 different general approaches to VTE treatment
- initial therapy and long term therapy using a single agent
- initial therapy and long term therapy using DIFFERENT agents (bridge when changing to warfarin - temp overlap)
- initial therapy and then long term therapy using DOACs
explain the bridged therapy in treating VTE
start with parenteral + warfarin
(parenteral can be heparin, LMWH, or fondaparinux) for at LEAST 5 days, and then drop the parenteral, and continue just the warfarin for months
explain the strategy for VTE treatment of using initial therapy and then DOACs but with NO bridge
start with parenteral (heparin, LMWH, fondaparinux) and then switch to either dabigatran or edoxaban
explain the 1st of the 3 VTE treatment strategies
can just use xarelto or eliquis or fondaparinux or LMWH for months
guidelines for long term agents for patients that do NOT have cancer
what if they DO have cancer
1st - DOAC, then warfarin, then LMWH
have cancer - DOAC, LMWH, warfarin or unfrac heparin
the duration of therapy for VTE treatment depends on…..
the risk of recurrence
for example, was it unprovoked? – would need long therapy (but if high bleeding risk - only 3 months)
was it provoked by durgery or a period of stasis? - just give for 3 months
give 3 scenarios in which the duration of VTE treatment would be EXTENDED
-unprovoked and low bleeding risk
recurrence
active cancer
in anyone that stops getting anticoagulation treatment for VTE, what should be considered?
giving aspirin
*****when do we not give fondaparinux
creatinine clearance less than 30!
true or false
fondaparinux can be used for both initial AND long term therapy for VTE treatment
true
what is the general monitoring when administering any anticoagulant
bleeding, periodic CBC, platelet, serum creatinine
should we check the coagulation panel when administering fondaparinux
no need to, but does elevate anti-xa if we do check
true or false
fondaparinux is NOT associated with HIT
true
black box warning fondaparinux and what can be done to rpevent
hematoma/bleeding when used during and after a lumbar puncture, epidural, or spinal anasthesia — have to space out before procedure!!!!
fondaparinux can cause thrombocytopenia
it should be discontinued and not used if the platelets fall below….
100,000
can heparin be used for long term therapy for VTE treatment
no – only for initial and bridge therapy
heparin can be used as bridge therapy with warfarin
to take the heparin off and continue just the warfarin, what criteria MUST be met
must be given for both:
5 or more days
INR must be 2 or more
when giving heparin for TREATING vte, the dose must be titrated to meet…….
what is route of administration in this case
the goal aPTT
given as bolus dose IV and then by continuous infusionbased on WEIGHT
use the nomogram!!! simplified titrating and dosing instructions to minimize errors
name 5 AE of heparin when given at therapeutic, weight based dosing
HIT
hemorrhage
osteoporosis (only with long term use - 6 or more months - rare - chronic effect)
hyperkalemia
hypersensitivty rxns
prolonged aPTT
blood is taking too long to clot - can be a side effect of heparin - risk of bleeding
pt is on heparin and aPTT is prolonged. what to do if:
-no suspicion of bleeding
-evidence of bleeding
no suspicion - discontinue the heparin and monitor
bleeding - discontinue and give volume replacement as needed — fluid, blood, plasma, clotting factor concentrates
can also use protamine!
protamine is used as the reversal agent for heparin
it can be administered if heparin caused bleeding
1mg of protamine neutralizes ______ of heparin BUT
100 units
it has a half life of 7 minutes
using heparin to TREAT VTE:
-bolus dose
-continuous infusion dose
bolus - 80 units/kg (round to nearest 500 units)
18 uinits/kg/hr (round to nearest 100 units)
