Pulmonary Circulation Disorders - Exam 2 Flashcards
What is the MC source of PEs? What do fat PEs arise from? What do septic emboli arise from?
thrombus arising from the deep veins of the lower extremities
long bone fractures
acute infective endocarditis
_______ occurs most often when small emboli lodge distally where there is a little collateral blood flow
infarction
What are the 3 pathophysiological response from pulmonary vascular obstruction?
infarction
impaired gas exchange leading to hypoxia
cardiovascular compromise
What does impaired gas exchange leading to hypoxia lead to?
altered ventilation to perfusion ratio
Inflammation → Surfactant dysfunction → Atelectasis → Functional intrapulmonary shunting
Stimulation of the respiratory drive → hypocapnia and respiratory alkalosis
What is the pathophys behind cardiovascular compromise?
Obstruction of the vascular bed → Increased pulmonary vascular resistance → Right heart and intraventricular septal strain
Less blood returning to the left ventricle → Reduced cardiac output → Hypotension
**What is Virchow’s triangle? What does it increase your risk for?
venous stasis
injury to the vessel wall
hypercoagulability
increased risk for PE
What are the risk factors for venous stasis?
immobility
hyperviscosity
increased central venous pressures (low cardiac output states and pregnancy)
What are the risk factors for hypercoagulability?
medications
disease: malignancy or surgery
inherited gene defects: factor V leiden, protein C, S and antithrombin deficiency, prothrombin gene mutation, hyperhomocysteinemia, antiphospholipid antibodies
What is the MC inherited gene defect that leads to hypercoagulability?
Factor V leiden
What are the MC s/s of PE? What does significant pain indicate? _____ is the most reliable physical exam finding
dyspnea, pleuritic chest pain, cough
small PEs that result in infarction
tachypnea
What are s/s of DVT?
Lower leg pain or “charley horse” in the calf
Associated symptoms DVT: swelling, warmth and/or erythema
What is the scale of Wells criteria for PE tell you? **What are the ranges of the scale?
determines the pre-test probability of the s/s being a PE
Determine “pre-test” probability
>6 points = high risk (78.4%)
2–6 points = moderate risk (27.8%)
<2 points = low risk (3.4%)
When are the PERC rules used? What are the PERC rules? **What does it stand for?
PERC rules are only used if Well’s risk is low risk
PERC Rules (Pulmonary Embolism Rule-Out Criteria)
What do you do if the pt is low risk and no PERC rules criteria are met?
no testing is needed
What do you do if the pt is low risk and there is at least 1 positive PERC rule?
move on to plasma D-dimer
Normal → no imaging
Elevated d-dimer → imaging
What do you do if the pt is intermediate risk?
D- dimer
Normal → no imaging
Elevated d-dimer → imaging
What do you do if the pt is high risk?
Imaging (no D-dimer)
What does a positive D-dimer indicate? What is normal?
A protein fragment from a broken down blood clot
normal is less than 500 ng/ml
**What is the equation for age adjusted d-dimer? What age do you need to adjust?
Adults over age 50 use an age-adjusted threshold (age × 10 ng/mL)
T/F: All elevated d-dimer are diagnostic for a PE/DVT
False!!! there are lots of false positive aka non-PE reasons why the d-dimer would be elevated
What are some reasons why the d-dimer would be elevated?
age >50 years, recent surgery or trauma, acute illness, PREGNANCY or postpartum state, rheumatologic disease, renal dysfunction and sickle cell disease
What is the first line imaging modality in PE? Does it require contrast? What will the radiologist report find?
CTA
YES! requires IV contrast (need to order BUN/Cr before)
**positive filling defect
What are the cautions for a CTA?
pregnancy, metformin and allergy to contrast dye
What is the preferred imaging of choice for PE when a pt is pregnant? Name some additional indications.
V/Q scan
pregnancy, renal insufficiency or adverse reaction to contrast
When a PE is present, what will the V/Q results say?
PE is likely when there is reduced perfusion with normal ventilation
** _____ is the gold standard for diagnosing PE. When is it indicate?
pulmonary angiography
Indicated when there is high pre-test probability and inconclusive CTA results
____ and ____ are elevated in up to 25-50% of patients. What are they related to?
troponin and BNP
related to size of PE causing acute right ventricular myocardial stretch
**What are the MC EKG findings associated with PE?
sinus tachycardia
non-specific ST segment and T-wave changes affecting R precordial leads V1-3 +/- V4
S1Q3T3 pattern +/- new incomplete RBBB
**What are 2 rare CXR findings that are associated with PEs?
westermark’s sign and hampton’s hump
**______ is an area of lung oligemia, usually from complete lobar artery obstruction
Westermark’s sign
**______ is a dome-shaped dense opacification in the periphery of the lung - indicative of pulmonary infarction
Hampton’s hump
Why is a lower extremity venous doppler ordered?
to look for evidence of DVT and helps to determine the etiology of the PE
What qualifies as a high risk PE?
hypotension (SBP < 90 mmHg for > 15 minutes)
drop in SBP > 40 mmHg below baseline
hypotension requiring vasopressors
causing a cardiac arrest
What qualifies as an intermediate risk PE?
Hemodynamic stability with signs of R sided heart strain/dysfunction via CTA, echo, elevated troponin or BNP.
aka right heart strain
What qualifies as a low-risk PE?
Normotension without signs of right ventricular dysfunction
aka no signs of right heart strain
What is the initial management of PE in ALL patients? What do you need to avoid?
supplemental oxygen
ventilatory support
hemodynamic support
avoid excessive IV fluids → increased risk of right sided heart failure
What are the 3 primary forms of therapy in a PE?
Anticoagulation - mainstay
Fibrinolysis
Thrombectomy
What is the MOA of unfractionated heparin?
Binds to and accelerates the activity of antithrombin, preventing additional thrombus formation
**What is the UFH dosing?
80 units/kg/dose IV bolus x 1 (or 5000 U) followed by 18 units/kg/hour (max 2000 u/hr)
What is the monitoring requirements for UFH?
Monitoring required: obtain aPTT at baseline and every 6 hours during tx with a goal of 60-80 seconds, signs of bleeding, H/H, plt
**When is UFH used? Who is it reserved for?
in high risk patients! anticoag may be given before imaging confirms dx
Reserved for unstable patients, severe renal insufficiency
**What is the reversal agent for UFH? What is a normal aPTT?
Protamine sulfate
normal aPTT 25-30 seconds
**What is the dosing for LMWH? When is LMWH preferred?
enoxaparin (Lovenox) 1 mg/kg SC q12h
Preferred over other injectable agents in those who can not take oral anticoagulants
When do you need to monitor LMWH?
Monitoring only in obese, underweight (<45 kg) or renal impairment
**What is the reversal agent for LMWH?
Protamine sulfate - reverses effects of heparin
Indicated for life-threatening or intracranial hemorrhage
What are the 3 factor Xa inhibitors? What are the dosing for each? Which requires bridging with heparin?
rivaroxaban (Xarelto), apixaban (Eliquis), edoxaban (Savaysa)
xarelto starts at BID dosing then decreases to QD
apixaban and edoxaban are BID dosing
savaysa requires bridging therapy with LMWH or UFH
What is the reversal agent for factor Xa inhibitors?
andexxa
_____ is the direct thrombin inhibitor. Does it require UFH/LMWH bridging? What is the reversal agent?
dabigaran (pradaxa)- BID dosing
Requires 5-10 days of bridging with UFH/LMWH
Praxbind
_____ is the only injectable factor Xa inhibitor. What is the dosing?
fondaparinux (Arixtra)
once daily, subq dosing
____ is a Vitamin K antagonist prevents activation of coagulation factors II, VII, IX, and X. How long does it take to reach its full effect? What is the ideal INR?
Warfarin
5 days to reach full effect
requires bridging with LMWH until INR is 2-3
_____ is used in high risk PE patients. How is it given to pts?
Tissue Plasminogen Activator (tPA) - Alteplase
100 mg IV infused over 2 hours
**What are the CI to tPA?
intracranial disease (active tumor or hx of bleed)
uncontrolled HTN (>220/110) at presentation
recent major surgery or trauma (past 3 weeks)
ischemic CVA in last 3 months
metastatic cancer
When is embolectomy used in PE management? What is commonly injected during the procedure?
Hemodynamically unstable patients with a contraindication or failure to respond to tPA
Catheter-directed procedure offers the benefit of locally injecting tPA at a lower dose decreasing bleeding risk
_____ is used to prevent PE recurrence and is indicated in active bleeding that prevents anticoag and/or recurrent VTE despite intensive anticoag
IVC filter
Where is an IVC filter placed?
below the renal arteries in the inferior VC
What are the indications for inpt PE treatment?
Severe illness or presence risk factors
Associated DVT
Educational needs (eg, lack of knowledge about PE and its management)
Problematic social situations (eg, prior noncompliance with follow-up care)
What are the risk factors that indicate admission for PE?
What is the longterm management for PE? What is the minimum?
anticoag therapy for a minimum for 3-6 months but can be indefinite
What do you need to do if there is no obvious cause of VTE is identified?
consult hematology
What is the normal mean pulmonary arterial pressure?
10-18mmHg
systolic pressure around 25mmHg
diastolic pressure around 10mmHg
What is the pathophys behind pulmonary hypertension? What is the mPap?
Increase in pulmonary vascular resistance, typically due to vasoconstriction, remodeling, and thrombosis of the small pulmonary arteries and arterioles leading to hyperplasia and hypertrophy of the vessels.
Pulmonary hypertension is defined by (mPAP) >20 mmHg
according to WHO, what are the 5 classifications of pulmonary hypertension?
group 1: idiopathic, hereditary, drug induced, connective tissue disease, congenital heart, HIV
group 2: LEFT sided heart disease
group 3: chronic hypoxia
group 4: chronic PE
group 5: catch all
What are the 3 MC symptoms of pulmonary hypertension?
malaise, fatigue and dyspnea
What does hemoptysis indicate in pulmonary hypertension?
rare - life threatening - results from rupture of pulmonary artery
What will late disease pulmonary hypertension present like? What additional heart sounds may be heard?
right sided heart failure
Accentuated P2¹ (pulmonic valve closure)
3rd heart sound (“Kentucky”)
tricuspid regurg murmur
What does cyanosis in pulmonary hypertension indicate?
consider open patent foramen ovale
What will the EKG of a pt with pulmonary hypertension show? What will TTE with doppler show?
signs of RVH
Elevated estimated pulmonary artery systolic pressure (ePASP)
Tricuspid regurgitation, RV enlargement, wall thickness or dysfunction may be seen
**What is the gold standard dx test for pulmonary hypertension? What will it show?
Right-sided heart catheterization (aka Swan-Ganz catheter)
mPAP ≥ 20 mmHg diagnostic for PH
What does a pulmonary capillary wedge pressure assess? What happens if it is increased?
LEFT sided heart disease
≤15 mm Hg = no left sided heart disease
Elevated PCWP usually indicates left sided heart disease and should be confirmed with a left heart cath
What is the vasodilator response?
After injection of a vasodilator, pressures are remeasured
Drop of mPAP of 10-40 mmHg indicative of positive acute vasodilator response
What is the diagnostic approach to pulmonary hypertension?
What are some general management measures for pulmonary hypertension?
What are the New York Heart Association system for classifying pulmonary hypertension?
What are the NYHA symptoms for pulmonary hypertension?
NYHA Symptoms: dyspnea, fatigue, chest pain, or near syncope with exertion.
What is the step wise treatment for pulmonary hypertension?
When are CCB used in pulmonary hypertension? Which ones specifically?
NYHA class I-III
High dose diltiazem and nifedipine most commonly used
What is the MOA for endothelin receptor antagonist?
reduces endothelin release leading to vasodilation
aka decrease in endothelin leads to decrease in vasorestriction so more dilation
ambrisentan (Volibris)
bosentan (Tracleer)
macitentan(Opsumit)
What drug class?
Endothelin receptor antagonists
What is the MOA for PDE5 inhibitors? What are the 2 medications in this class?
inhibition of PDE5 leads to vasodilation
sildenafil (Viagra, Revatio)
tadalafil (Cialis, Adcirca)
What is the MOA of Soluble guanylate cyclase stimulators? What is the drug in this class?
stimulates the activity of guanylate cyclase which increases CAMP in the lungs as a response to nitric oxide, which causes the arteries to vasodilate
riociguat (Adempas) -> only available PO
What is the MOA of prostanoid agents?
potent pulmonary vasodilation by acting on prostaglandin receptors with an additional benefit of inhibiting platelet aggregation
epoprostenol (Flolan)
treprostinil
iloprost
What drug class?
prostanoid agents
What is the MOA of prostacyclin receptor agonists? what form?
attaches to and activates prostacyclin receptors in the lung resulting in vasodilation
available IV and PO: IV only for short term if unable to take PO
Prostacyclin receptor agonists are more selective for the _____ than the ______
prostacyclin receptor
prostanoid agents
What is the tx of pulmonary hypertension based on the NYHA categories?
What is the additional management for pulmonary hypertension?
**What are the 2 MC EKG abnormalities on the MAJORITIES of PE’s?
sinus tachycardia
non-specific ST segment and T wave changes affecting R precordial leads V1-3 +/- V4
