Pulmonary Embolism Flashcards
1
Q
Pulmonary embolism
A
An obstruction of the pulmonary artery or one of its branches, caused by material (thrombus, tumor, air, or fat) which traveled from another location of the body.
2
Q
Virchow’s Triad
A
- Hypercoagulability (cancer, thrombophilia, inflammatory disease).
- Vessel wall injury (surgery, chemical irritation, inflammation)
- Stasis of blood
3
Q
Risk Factors
A
- pregnancy
- malignancy
- central venous catheter
- surgery
- trauma
- heart failure
- immobilization
- oral contraceptives
- hormone therapy
- congenital heart disease
- severe liver disease
- IBD
- Inherited thrombophilia (factor V, antithrombin deficiency)
4
Q
Location of embolism
A
- Saddle (inner)
- Lobar
- Segmental
- subsegmental
- moving distally
5
Q
Clinical presentation of PE
A
- Dyspnea on exertion or at rest
- pleuritic chest pain
- calf or thigh pain/swelling
- orthopnea
- hemoptysis
- wheezing
6
Q
Signs of PE
A
- Tachypnea(54%)
- Edema, erythema, tenderness or a palpable cord in the calf or thigh(47%)
- Tachycardia(24%)
- Rales(18%)
- Decreased breath sounds(17%)
- Accentuated P2(15%)
- Jugular venous distention(14%)
- Fever
7
Q
Lab tests
A
- CBC: can have leukocytosis
- ESR: elevated
- LDH: elevated
- AST: elevated
- Metabolic Panel: evaluate renal function to determine ability to give contrast
- Troponin, BNP or NT-proBNP: used for risk stratification
8
Q
EKG
A
- Sinus tachycardia
- Nonspecific ST segment and T-wave changes
- Atrial arrhythmias
- New right bundle branch block
- S1Q3T3
9
Q
Chest Xray with PE
A
- Usually non-specific findings
- -cardiomegaly
- -pleural effusion
- -elevated hemidiaphragm
- -pulmonary artery enlargement
- -atelectasis
- Can also be normal in up to 22% of patients
10
Q
Chest CT
A
- Gold standard in diagnosing PE
- CT angiogram with contrast to visualize pulmonary arteries and assess for filling defect
- Contrast contraindicated in renal impairment (CrCl <30)
11
Q
Ventilation perfusion scan
A
- Need to have “normal” chest Xray, otherwise may have false positive
- Most are read as “indeterminate”
12
Q
Assessing RV
A
- Evaluation of right ventricular (RV) function is an important tool for risk assessment
- Screening can occur with either echocardiogram or prognostic biomarkers (troponin, BNP,) even if the PESI score is low
13
Q
Initial treatment
A
- hemodynamic stability
- Supple O2
- IV fluids or vasopressors
- if diagnostic testing is delayed empiric anticoagulation is often initiated
14
Q
Is anticoagulation appropriate?
A
- Determine pts bleeding risk
- absolute contraindications: hemorrhagic stroke, recent surgery, intracranial/spinal cord tumors, active bleeding
- Alternative tx: IVC filter or embolectomy
15
Q
Thrombolytics
A
-TNKase (tenecteplase) and Retavase (reteplase)
=Reserved for hemodynamically unstable patients
-RV strain without hypotension is not an indication for thrombolytics
-“Possible” indications:
Presence of severe hypoxemia, Extensive clot burden, Free floating intracardiac clot
16
Q
Contraindications for lytics: Absolute/major
A
Intracranial neoplasm or lesion
- Recent intracranial or spinal surgery/trauma (<2 months)
- History of hemorrhagic stroke
- Active bleeding
- Nonhemorrhagic stroke within last 3 months
- -Suspected aortic dissection
17
Q
Relative contraindications for lytics
A
-Uncontrolled hypertension (SBP> 200, DBP >110)
-Nonhemorrhagic stroke >3 months
-Surgery within the past 3 weeks
-Pregnancy
>75 years old
-Current anticoagulation use
18
Q
Alternative tx: These are considered if thrombolytics are contraindicated or has failed
A
- Catheter directed thrombolysis
- Surgical embolectomy
19
Q
Catheter directed thromboylysis
A
- Thrombolytics delivered directly to pulmonary arteries
- Usually reserved for patients who remain unstable after systemic thrombolytics
- Benefit: utilizes lower dose of lytic which reduces risk of bleeding
20
Q
Initial anticoagulation
A
- DOAC (apixaban and rivaroxaban can be used on day 1 of treatment, edoxaban and dabigatran requires 5-10 days pf bridging)
- LMWH
- UFH
21
Q
Unfractionated Heparin
A
- Mechanism of Action: Binds to antithrombin, resulting in structural change and increase ability to inactivate factor Xa and thrombin
- Half life ½- 2 hours
- Can be used in pregnancy and renal impairment
- Reversal: Protamine
22
Q
Low Molecular Weight Heparin (Lovenox)
A
- Same mechanism of action as UFH
- Contraindicated if creatinine clearance is <30 mL/min
- Half life approx 12 hours
- Reversal: Protamine
23
Q
Heparin Induced Thrombocytopenia
A
-Defined as platelet count falling by ≥50%
-4 T’s Criteria (MD Calc)
-Must be confirmed by heparin antibody assay (PF4), if confirmed, list heparin as allergy
-Alternative anticoagulants should be utilized:
Argatroban, bivalrudin, fondaparinux
-If HIT is confirmed, once platelet counts have recovered (typically >50k), can initiate warfarin as there is increased risk of clotting with HIT
24
Q
DOAC
A
- Rivaroxaban, apixaban, edoxaban, dabigatran
- Currently no generic in the US
- All DOACs have overall lower all cause mortality related to bleeding when compared to warfarin
- Apixaban and low dose edoxaban have lower GI bleeding rates compared to warfarin
25
DOAC MOA
- Oral direct factor Xa inhibitors include apixaban, rivaroxaban, and edoxaban and they work by preventing factor Xa from attaching prothrombin to thrombin.
- Oral direct thrombin inhibitors (dabigatran) works by preventing thrombin from attaching fibrinogen to fibrin
26
Pros to DOACS
- No dietary restrictions
- No monitoring
- Does not require bridging (apixaban and rivaroxaban)
- Fewer drug-drug interactions
- Lower rates of bleeding when compared to warfarin
27
Cons to DOACS
- Unclear dosing with obesity
- Reversal not readily available at smaller institutions
- Limited research in severe renal impairment
- Some require twice daily dosing
- Cost
28
DOAC drug-drug interactions: Increases DOAC blood levels
-Clarithromycin/erythromycin
-Verapamil/diltiazem
-Amiodarone
Fluconazole/ketoconazole/itraconazole
-Cyclosporine/tacrolimus
29
DOAC drug-drug interactions: Decreases DOAC blood levels
- Aniepileptics (Phenytoin, Phenobarbital, Carbamazepine)
- Rifampin
- St. John’s Wart
30
DOAC reversals: Dabigatran (Pradaxa)
-Idarucizumab (Praxbind); initial dose: 5 grams
31
DOAC Reversals: Apixaban (Elliquis), Betrixaban (Bevyxxa), Edoxaban (Lixiana, Savaysa), Rivaroxaban (Xarelto)
-Andexanet alfa (AndexXa) if available: initial dose depends on the dose of the factor Xa inhibitors and the interval since the last dose
OR
-4-factor PCC (Kcentra, Octapiex) if andexanet alfa is not available; initial dose 50 units per kg
32
Warfarin
- Mechanism of action: Blocks the conversion of inactive vitamin K to its active form within the liver resulting in non-functioning clotting factors
- Active clotting factors need to be depleted before fully anticoagulated
- Full therapeutic affect is usually achieved in 5-7 days
- Half life 12-72 hours
- Reversals: Vitamin K, FFP
33
Warfarin Pros
- Inexpensive
- Several reversal agents, easily accessible
- Able to monitor for compliance
- No renal restrictions
- Once daily dosing
34
Warfarin Cons
- Requires bridging
- Requires monitoring
- Dietary restrictions
- Higher rates of bleeding compared to DOACs
- Several drug-drug interactions
- Usually only therapeutic 65% of time
35
Warfarin Bridging
-When transitioning to warfarin from LMWH or UFH:
LMWH or UFH should have been used for at least 5 days
-INR should be ≥2.0 for 2 days before discontinuing LMWH or UF
-Does not require hospitalization if patient is stable
36
Duration of therapy
- Provoked VTE should be treated for typically 3 months
- Malignancy related PE should continue treatment while they have active cancer
- Unprovoked VTE, after 3 months should be assessed for bleeding risk, but should be considered for prolonged secondary prevention
- Consider Thrombophilia follow up for guidance on duration of therapy for special circumstances
37
Provoked
-Surgery with general anesthesia
-Cesarean section
-Confined to bed for at least 3 days
-Estrogen therapy
-Pregnancy
-Active cancer
-Inflammatory bowel disease
-Reduced mobility >3 days
Inheritable thrombophilia
38
Primary Prevention for VTE
- Heparin (5,000 units subQ every 8 hours)
| - Lovenox, typical dose is 40 mg daily
39
IVC Filter
Used for patients who anticoagulation is contraindicated, anticoagulation has failed, or complication from anticoagulation has occurred
40
Treatment w/ concurrent malignancy
-Prior to 2019, recommendation for treatment of VTE in the setting of malignancy was LMWH, research has shown superior efficacy with apixaban
