Flashcards in CM- Pulmonary Vascular Diseases Deck (65):
Where do most pulmonary emboli originate? How do they get to the pulmonary arteries?
Most originate in deep veins of the leg:
But they can also come from:
5. upper extremity veins
They dislodge from the wall of the vein, travel through the great veins and lodge in pulmonary arteries
How do most DVT develop?
1. Venous stasis- recent paralysis, cast, +/- bedrest
2. Injury to vein wall - catheter, physical trauma, minor injury
3. Hypercoagulable state - inherited/acquired
More than half of individuals with a first-diagnosis of venous thromboembolism have one of what 4 risk factors withoin the prior 90 days?
4. major trauma
In addition to hospital admission, trauma, malignancy, and surgery, what are the other important risk factors for DVT/PE?
3. immobility of lower limbs
4. acute infectious disease
5. older age
6. family history of hypercoagulable state
What are the 3 most common physical exam findings of DVT?
1. unilateral leg swelling
2. palpable venous cord in thigh/calf
3. Homan's sign- pain with foot dorsiflexion
A meta-analysis on DVT found that the only significantly helpful INDIVIDUAL physical exam finding for predicting PE occurrence was:
Difference in calf diameters by 3 cm
How is the Wells Rules scored?
What is the only thing that gives "negative" points?
High probability = >3
Moderate score = 1-2
Low score <0
Alternative diagnosis as likely or greater than DVT gives -2 points
What is the most common diagnostic test used to confirm a DVT?
What are the 2 parts of the test?
Where is this test highly sensitive and specific for DVT?
What veins can it NOT be used for?
Non-invasive compression Duplex ultrasonography:
1. compression - shows areas of the vein that are non compressible due to clot
2. Doppler- confirms lack of blood flow
It is highly sensitive and specific for DVT below the inguinal ligament (legs) but cannot image clots in the iliac vein or IVC
When compression duplex ultrasonography is inconclusive or cannot be performed (pelvic vein or IVC) what test would be ordered?
Venography - invasive test that is the Gold Standard for DVT but not frequently used due to invasive nature and use of contrast (a cause of allergic reactions or renal failure)
What is the gold standard test overall for DVT?
Why is it not commonly used?
Venography- it is not commonly used because it is invasive and requires contrast which can cause allergic reaction and renal failure in patients with renal disease.
When is a CT scan a good choice for looking for pelvic vein DVTs?
When you are already doing a CT angiogram on the chest for PE.
It is invasive and requires contrast, but imaging the pelvic veins requires no EXTRA contrast from what was being used in the chest to look for PE
Congenital deficiencies in what 3 factors and mutations in what 2 factors are thought to increase the risk for DVT?
How would you know to look for inherited hypercogulable states?
The following are natural anticoagulants that decrease clot formation by inhibiting/degrading clotting factors. Deficiencies cause thrombus formation
1. Protein C
2. Protein S
3. Antithrombin III
Gene mutations can lead to abnormal:
2. factor V (Leiden)
The conditions are autosomal dominant so when taking the family history, note if a parent or sibling has DVT or PE history.
What is the most common of the inherited anticoagulable states?
Factor V Leiden - resists protein C mediation which increases the risk for thrombus formation
Patients with inherited hypercoagulable states have DVT at a _______ age, without _____________, and thrombus form in ____________________.
Younger age, without clinical risk factors, and thrombus form in unusual locations like arms or mesenteric veins
What are acquired deficiencies that lead to hypercoagulable states?
1. lupus anticoagulant
2. Anti-cardiolipin antibodies
Is hyperhomocystinemia acquired or inherited?
What can lead to increased levels?
It can be acquired, inherited or both as a common genetic variant.
Deficiencies in folate, B12, or B6 can lead to hyperhomocystenemia which increases risk for DVT
What preventable risk increases the relative risk of a heterozygous with Factor V Leiden from 7 to 35?
Who has a higher risk for developing a DVT, a person with homozygous Factor V Leiden or someone in their first year off anticoagulation after an idiopathic DVT?
Off anticoagulant = 7-8% incidence per year
Factor V Leiden = 0.5-1% incidence per year
Who has the highest risk for developing a DVT?
What are the pros and cons of genetic testing for patients with venous thrombus at young age?
Factor V Leiden patients can avoid going on birth control or estrogen pills
-Most patients will not have different treatment based on testing
-asymptomatic carriers do not require anticoagulation
The effect of a pulmonary embolism on a patient depends on what two factors?
What % of pulmonary circulation needs to be occluded to result in sudden death or profound cardiogenic shock?
1. size of the clot
2. amount of pre-existant cardiopulmonary disease
75% occlusion can lead to sudden death/cardiogenic shock
Most PE do not cause infarction of the lung because the lung has _______________.
However, in the 1/3 of cases where there is infarction, what are the clinical signs?
Lung has dual blood supply so it usually will not infarct.
If it does, the patient will present with:
3. pleural friction rub
and a wedge shaped infarct, often mistaken for pneumonia
What are the most common symptoms of a common PE?
1. tachypnea- because perfusion is blocked but ventilation is fine. Breath faster/deeper due to increased dead space
2. acute dyspnea- (most other dyspnea is gradual)
3. Chest pain
What are the 3 most common symptoms associated with a large PE?
What are the three symptoms suggestive of a PE causing an infarct?
1. Pleural Rub
What are the 3 basic diagnostic tests done for PE?
1. ABG- hypoxemic with large A-a gradient and acute respiratory alkalosis due to tachypnea. PaO2 <1.5mg/L in a low suspicion person = no extra tests
What are the ABG findings for PE?
1. wide A-a gradient
2. hypoxemic with PaO2 <80mmHG
3. respiratory alkalosis due to tachypnea
What are the 3 potential findings on a CXR for a person with PE?
List from "least bad" to worst scenario.
1. No changes on CXR except slight atelectasis
2. Segmental oligemia- decreased blood vessels to a lobe of the lung (Westermark's sign)
3. Hampton's Hump - wedge shaped density in the periphery suggests infarcted lung
What 2 things score a 3 on Wells Rules for PE?
1. no alternative diagnosis more likely than PE
2. clinical signs/symptoms of DVT
What 3 things score a 1.5 on Wells Rules for PE?
1. Heart rate >100
2. immobilization/surgery in last month
3. previous DVT or PE
What 2 things score a 1 on Wells Rules for PE?
2. cancer in the last 6 months
What is low, moderate and high score on wells rules for PE?
What are the 3 tests that are necessary to confirm the diagnosis of PE?
Which is the preferred test in patients with normal renal function? Why?
1. CT angiogram- preferred test if they have normal renal function bc it has good specificity/sensitivity and can diagnose other causes of dyspnea/chest pain (pneumonia, pleural effusion, aortic dissection)
2. VQ lung scan
3. pulmonary angiogram
What are D-dimer tests used for as a diagnostic for PE?
When and where are they performed?
A negative test is sufficient to rule out a low-suspicion patient. However, false + are common
They are done in an outpatient setting when the risk of PE is low
When are CT angiograms performed?
What are the pros and cons?
They are done when there is a high suspicion for PE.
1. allow direct visualization of the vessels/PE and can report as + or - for PE.
2. can diagnose alternative causes of chest pain/dyspnea
1. require IV contrast
2. Shouldn't be done in people with poor renal function
3. false + and false - with smaller emboli
When are VQ lung scan performed?
How is it done?
What are the pros and cons?
They are nuclear medicine tests performed when there is a high suspicion for PE
1.Patient inhales radioactive xenon that is distributed through open airways to normally ventilated lungs.
2. Radiolabeled albumin is injected IV
3. albumin clumps in well perfused pulmonary capillaries
4. Area with PE will have absence of perfusion but not ventilation
1. can use in patients unable to receive contrast (allergic or poor renal function)
2. first choice for CHRONIC PE
Reported as low, medium, high risk for PE so not as definitive as the CT angiogram
What are the pros and cons of using pulmonary angiography for diagnosing PE?
It is the gold standard for acute/chronic PE
1. requires interventional radiologist to perform it
2. invasive- requires insertion of femoral/internal jugular central access
3. requires contrast
Findings of VQ perfusion scans must be interpreted in the context of pre-test clinical suspicion.
What is the change of PE if :
1. completely normal scan
2. low clinical suspicion (80%) and high probability scan
What if there is a situation that does not match on of the above three, for instance, low clinical suspicion, but high probability scan?
1. rules out PE
2. effectively rules out PE
3. PE diagnosed
If the clinical suspicion and VQ perfusion scan do not match, you must do a pulmonary angiography to confirm suspicions.
What is therapy for PE?
2. Thrombolytics if life threatening
What is the normal resistance of pulmonary circulation?
What are the normal pressures of systolic and diastolic pulmonary circulation?
Why are the resistance and pressure normally low?
Resistance : 20-120 dynes
Systolic pressure = 15-30mmHg
Diastolic pressure = 3-12mmHg
Resistance and pressure are low due to highly compliant thin walled arteries
What is the definition of pulmonary hypertension?
-mean pulmonary artery pressure >25mmHg
- systolic pulmonary artery pressure of 40mmHg
What causes acute pulmonary hypertension?
Acute = pulmonary embolism
Chronic = left heart failure, lung disease
What are the effects of pulmonary hypertension on the heart?
Increased pressure causes RV hypertrophy and dilation.
What are the 3 main ways pulmonary hypertension develop?
1. increased pulmonary vascular resistance
2. increased pulmonary venous pressure
3. increased flow = need to maintain gradient (hard to get but mainly with ASD, VSD)
What are the earliest symptoms of pulmonary hypertension?
1. Dyspnea on exertion
2. chest pain
What are the 5 main signs/symptoms of RH failure?
1. dependent edema
2. orthopnea, DOE
3. elevated jugular venous pressure
4. loud P2, S3 gallop of RV that gets louder with inspiration, RV heave
5. TR murmur
What are the 5 clinical classifications of pulmonary hypertension?
1. PAH (arterial- small vessels)
2. pulmonary venous hypertension due to LH
3. pulmonary hypertension from hypoxia/lung disease
4. Chronic pulmonary emboli
5. Miscellaneous/uncommon conditions
What 3 diseases are included under group 1 PH?
What does catheterization show of PA pressure and capillary wedge pressure?
How do you make the diagnosis for group 1?
What is treatment?
Pulmonary arterial hypertension:
1. idiopathic PAH
2. connective tissue disease (lupus, scleroderma)
3. congenital heart disease
Catheterization shows PA mean pressure >25 and a pulmonary capillary wedge pressure <15
Diagnosis : exclusion of LH disease, lung disease, chronic thromboembolism
Treatment: only group with specific approved medicine
What are the diseases of group 2 pulm. hypertension?
What does wedge pressure show?
Pulmonary venous hypertension due to left heart failure:
Elevated capillary wedge pressure above 15mmHg caused by elevated pressures in the LV and LA
What is the most common cause of PH overall?
Group 2 PH- pulm. venous hypertension due to left heart failure
What are the 3 major diseases associated with group 3 pulmonary hypertension?
What can prevent it?
Pulmonary hypertension due to hypoxia/lung disease:
Interstitial lung disease
severe sleep apnea
Oxygen therapy in COPD can prevent this, but once PH develops, oxygen doesnt help/reverse the changes
What is the major cause of group 4 pulmonary hypertension?
What is the required treatment?
Chronic pulmonary emboli- that either the clot doesnt resolve or there are multiple separate PEs.
Require surgical treatment but often still can't cure
For group 3 pulmonary hypertension, the pulmonary arterial pressures correlate best with _______________ rather than _________________.
PA pressure correlates best with oxygen saturation rather than other measures of severity such as lung function testing (spirometry)
What is treatment chronic thromboembolic disease?
How is it distinguished from idiopathic PAH?
Medical therapy is considered in patients with distal disease who are not candidates for surgery
Distinguish it from PAH by doing a VQ perfusion test.
The most common cause of pulmonary arterial hypertension is ___________________.
Pulmonary venous hypertension
What are things that can increase vascular resistance and lead to pulmonary hypertension?
2. vascular cell growth or destruction (emphysema)
3. hypoxia which causes vasoconstriction and vascular growth
In what clinical situation would you see a plexiform lesion?
Idiopathic PAH- an abnormal increase in vasoconstriction combined with vascular growth causes obliteration and plexiform lesions with vascular resistance 3-15x normal
What are common causes of increased flow through pulmonary circulation?
VSD, ASD, PDA
Describe the relationship between flow, pressure, and venous pressure using the equation for PVR/
PVR = (mean PA pressure- PCWP)/ CO
What are the CXR findings for pulmonary hypertension?
What would be the findings for pulmonary VENOUS hypertension?
- enlarged pulmonary arteries
- RV dilation
- azygous vein distention
1. kerley B lines, intestitial edema
2. cephalization of pulm veins
3. alveolar edema
The diameter of the right descending pulmonary artery can be measured on X-ray and a diameter of _________ predicts pulmonary hypertension.
diameter >2cm indicates pulmonary hypertension
Venous hypertension shows graded series of radiographic changes. What is seen if the pressure is elevated by:
1. upper lobe veins appear more prominent which is called cephalization
2 interstitial edema with Kerley B lines (abutting the pleural surface of lower lobes)
3. fluffy, ill-defined nodules due to pulmonary edema in the alveolar space
What is the best screening test for pulmonary hypertension?
echocardiogram because it gives information about:
1. pulmonary arterial systolic pressure can be estimated in most (upper limit of normal is 40mmHg)
2. RV size and systolic function (pressure will be within 10 of actual pressure) can be estimated
3. LH function, valvular disease, and congenital heart disease can be seen
After getting an echo, non-invasive testing is done first. What is the major purpose of non-invasive testing?
Identifying and excluding group II-IV
1. Heart disease- echo
2. lung disease- CXR, O2 sat, PFTs
3. chronic pulm emboli- VQ