Anticoagulation I Flashcards
Signs and Sx of DVT and PE
DVT
-Unilateral leg swelling (warmth, tender, discoloration)
-Pain behind knee/calf when flexing foot (+ Homan’s)
-Palpable cord
PE
-Dyspnea
-Tachycardia/tachypnea
-Chest pain/tightness
Diagnosis of DVT and PE
DVT
-US (+ dopple/b mode)
-Dimer 240+ (elevated)
-Wells score 2+
PE
-V/Q scan (+)
-Spiral CT
-Dimer 240+
-Wells PE score >4
Wells Score: DVT and PE
DVT
-Low: =< 0
-Mod: 1-2
-High: >= 3
PE
-Likely: > 4
-Unlikely: =< 4
General Approach: Treatment of VTE
- Cardiopulmonary compromise or high risk of limb loss = FIBrinolytic + UFH/LMWH
- Active bleeding or CI and lower extremity = IVC filter, initiate AC when cleared
- Poor prognosis/can’t tx output = hospitalize
-CrCl < 30 = UFH x 5 overlap warfarin
-CrCl 30+ = UFH x 5 overlap warfarin or UFH with DOAC transition OR vvv - Outpt tx = Riva/Apix/LMWH with fonda x 5 then dab/edox or LMWH x 5 overlap warfarin (RALF DWEL)
Risk Factors for Major Bleeding While Taking Anticoagulation Therapy
-65+
-NSAID use
-Hx of GI bleed
-Recent surgery/trauma
-Heavy alcohol use
-Renal failure
-Malignancy
-Initiation of tx
Fibrinolytic Drugs Potential
-Alteplase (t-PA)
-Tenecteplase (TNK)
-Streptokinase
-Urokinase
Potential to dissolve not only pathologic thrombi but physiologically appropriate fibrin clots
– could lead to hemorrhage of varying severity
*bc not site specific
Fibrinolytic Drugs: Indications/CI
Indications
1) Massive ileo-femoral DVT at risk for limb gangrene due to venous occlusion
2) Hemodynamically unstable PE patients (ie. SBP < 90, shock)
CI
-Active bleeding, hemorrhage hx
-Ischemic stroke within 3 months
-Cancer/vascular lesion
-Aortic dissection
-Trauma/surgery (head)
-Severe uncon HTN
(BIHH VCAT)
Fibrinolytic Drugs: Dosing
Before fibrinolytic therapy begins, administer IV heparin in full therapeutic doses (then suspend during fib tx)
Altepase
-PE: 100 mg IV infusion over 2 hours x 1 dose
-Cardiac arrest: 50 mg IV bolus x 1 dose
Initial Acute Phase Treatment
Rapid-acting (FULAR)
-UFH (IV/SC)
-SC LMWH
-SC Fondaparinux
-Oral rivaroxaban or apixaban
-Dab/edox not used bc need 5-10 days of parenteral tx first
Transition from parenteral therapy to orals:
–5 days and until INR 2-3 for at least 24 hr, then continue on PO warfarin alone = BEST PRACTICE
– No overlap is necessary if switching from parenteral therapy to rapid acting DOAC (rivaroxaban or apixaban)
Heparin: Monitoring
PREFERRED IN RENALLY IMPAIRED PTS = not renally excreted
Baseline Labs
* CBC with platelets
* PT/INR
* aPTT
* BUN
* Serum creatinine
Ongoing Labs
* aPTT or anti-Xa
– 6 hours after initial bolus
– every 6 hours until 2 consecutive aPTT / anti-Xa values are therapeutic, then daily
* CBC with platelets
– Daily if pretx < 100,000
– Every 72 hours if > 100,000
Heparin: Dosing
IV: 80 u/kg (max 10,000) followed by 18 u/k/hr (max rate 2,150 u/hr)
- goal aPTT 50-77 seconds
- goal anti-Xa 0.3-0.7 IU/mL
Heparin: Precautions and Side Effects
-Narrow therapeutic window
-Heparin induced thrombocytopenia
-Hemorrhage
-Hypersensitivity rxn
-Hyperkalemia
-Osteoporosis
(HHHHON)
LMWH: Enoxaparin/Dalteparin
Dosing/Monitoring
Enoxaparin
1mg/kg SC BID or 1.5-2.0 mg/kg SC daily
*renal adj req for both
Higher risk patients that may require monitoring: CCEO at 30
– obese pts
– renal, CrCl <30
– elderly/children
– cancer
Use anti-factor Xa
- labs: hemoglobin, hematocrit, platelet count
Heparin Induced Thrombocytopenia
- Platelet count drop of 50% from baseline
- Venous or arterial thrombosis
- Skin lesions at heparin injection sites
- Acute systemic reactions that occur after a bolus of IV heparin
*Prompt DC of ALL heparin products
-Initiation of argatroban/bivalirudin (ICU) or fondaparinux (= if stable) as alt
-Platelet count usually recovers in 4-7 days
4 Ts (thrombocyto/time/thrombosis/other)
- ≤3: low for HIT
– 4-5: intermediate
– 6-8: high for HIT
Fondaparinux (Arixtra®)
- < 50 kg: 5 mg SC daily
- 50-100 kg: 7.5 mg SC daily
- > 100 kg: 10 mg SC daily
CLcr < 30 mL/min: CONTRAINDICATED
Bivalirudin: DTI
Indications: CHC
– as alternative to heparin when undergoing coronary angioplasty or CABG
– as alternative to heparin in HIT
*renal adj
Normal dose: 0.15 mg/kg/hr
Argatroban: DTI
Used as alternative to heparin in patients with or at risk of developing HIT
*hepatic adj
Normal dose: 2 mcg/kg/min IV
ARG the pirate’s liver is 2 HIT
Dabigatran: DOAC
ONLY (dabi is 30 but acts 150, GRH she’s a B)
-Requires UFH/LMWH/Fonda beforehand
-CLcr > 30 after 5- 10 days of parenteral therapy:
= 150 mg PO BID
CLcr ≤ 30 mL/min: NO
For CLcr < 50 mL/min with concomitant use of P-gp inhibitors: avoid co- administration
AE:
-Bleeding, GI distress, rash, hives
Rivaroxaban: DOAC
ONLY (BOB goes down the river at 15 15 x2 x21 20)
CLcr ≥ 15 mL/min:
15 mg PO BID x 21 days then 20 mg PO qPM
CLcr < 15 mL/min: NO
To reduce risk of recurrence:
CLcr > 15 mL/min: 10 mg PO daily after at least 6 mo
AE:
-Bleeding, back pain, osteoarthritis
Apixaban: DOAC
10 mg PO BID x 7 days, then 5 mg PO BID thereafter
Reduce recurrence:
2.5 mg PO BID after at least 6 months of standard dosing
AE: bleeding
Edoxaban: DOAC
CLcr > 50 and after 5-10 days of parenteral therapy:
-Weight > 60 kg: 60 mg PO daily
For CLcr 15-50 mL/min or weight ≤ 60 kg or who use certain P-gp inhibitors1: 30 mg PO daily
CLcr < 15 mL/min: NO
AE: bleeding
Pt Education for DOAC’s
-Do not abruptly stop taking your blood thinner (risk of thrombotic events)
-Report any bleeding (unexpected/lasts long/uncontrolled)
-May have higher risk of bleeding if you take aspirin, NSAIDs, warfarin
*Rivaroxaban with evening meal
*Dabigatran: use within 4 mo of opening bottle, keep capsules in original bottle at RT
Warfarin: Monitoring
INR: 2-3
*2.5-3.5 for high-risk mechanical prosthetic heart valves
Get baseline labs (PT/INR, CBC, liver panel, albumin)
70+
-AA: 7.5
-CH: 5
-As: 2.5
=<70
-AA: 5
-CH: F 2.5, M 5
-As: 2.5
Warfarin: Drugs and Herbal Interactions
SAM CAP
-Pheny/Pheno
-Amiodarone
-Carb/cim/cipro
-Mycin
-Azoles
-SJW/sulf
Warfarin: Raising/Lowering Factors
Reduce starting dose by 2.5 mg or 50% (whichever is less) or increase starting dose by 2.5 mg or 50% (whichever is less)
Dose Lowering Factors
* Weight < 45 kg
* Baseline INR > 1.3
* Malnourishment
* Albumin < 3
* Liver disease
* Catabolic conditions (recent surgery, hyperthyroidism, ADHF, pneumonia)
* Taking azole antifungals, metronidazole, Septra, amiodarone
Dose Raising Factors
* Weight > 90 kg
* Untreated hypothyroidism
* Receiving enteral feeds
* Taking rifampin, carbamazepine, dicloxacillin, phenobarbital, bosentan
Warfarin: Toxicities
-Bleeding
-Birth defects (Cat X/D)
-Skin necrosis
-Purple toe
Warfarin: Patient Education
-Never skip a dose or take a double dose
-INR is the blood test used to determine how thin your blood is, will get it checked regularly
-Too much = bleeding, too little = clots
-AE: bleeding, bruising
-If you sustain an injury or fall OR you hit your head at any time, seek medical attention
-Food can affect it (green leafy veg) = keep diet consistent
-Alcohol limit 1 d/d
Transitioning to Warfarin
- When treating DVT/PE, overlap UFH/LMWH treatment with warfarin
– Must treat with both for at least 5 days
– Must have therapeutic INR for 2 consecutive days
Protamine sulfate
Reverses Heparin
- 1 mg protamine : 100 units circulating heparin
- t 1⁄2 60 minutes
- Administration: slow IV push over 1-3 minutes
- No more than 50 mg should be administered in a 10-minute period
– 1 mg protamine : 1 mg enoxaparin (if enox. given < 8 hours ago)
– 0.5 mg protamine : 1 mg enoxaparin (if enox. given > 8 hours ago)
AE:
– Dyspnea, wheezing, cyanosis
– Flushing, urticaria
– Chills
– Chest pain
– Nausea / vomiting
– Bradycardia, hypotension, anaphylactoid rxn
Vitamin K
PO preferred
reverse the effects of warfarin
4-factor prothrombin complex concentrates (KcentraTM)
Must be given with Vitamin K
Idarucizumab (PraxbindTM)
Only for dabigatran
FOR
1. emergency surgery / urgent surgical procedures
2. life-threatening or uncontrolled bleeding
DOSE: 2.5g/50mL IV bolus x 2 (total dose=5g)
RISK: possible thromboembolic complications
Andexanet Alfa (AndexXaTM)
- INDICATION:
– indicated for patients treated with rivaroxaban or apixaban, when reversal of anticoagulation is needed due to life-threatening or uncontrolled bleeding
RISK: possible thromboembolic complications
Fresh Frozen Plasma (FFP)
- 10-20 mL/kg will increase factor levels by 20-30%
- 1-unit FFP = 200 mL
