9/23- Pulmonary Vascular Diseases Flashcards
(54 cards)
1
Q
What are the systolic/diastolic/mean BP for pulmonary arteries?
Characteristics of pulmonary circulation?
A
Pulmonary circulation is high flow, low pressure, highly compliant system (low resistance)
- Systolic: 30 mmHg
- Diastolic: 10 mmHg
- Mean: 15 mmHg
2
Q
What regulates vascular tone in pulmonary circulature?
A
Vascular endothelium
- NO (dilator)
- Endothelin (constrictor)
Autonomic nervous system
- a1 adrenergic receps (constriction)
- B2 adrenergic receps (dilation)
3
Q
What is the mechanism of NO dilation of vasculature?
A
- Secreted by endothelial cells
- Activates guanylate cyclase (GC) to increase cGMP levels
- Also activates Ca dependent K channels in vascular smooth muscle
- Dilates both venous > arterial
- NO is a gas, which can be inhaled to result in primary pulmonary vasodilation
4
Q
What are the determinants of pulmonary artery pressure?
A
- Blood volume
- Rate of fluid flow through system (CO, viscosity, vessel size)
- Pressure inhibiting flow across cap bed (left atrial pressure)
- PAP = CO x (PVRa + PVRcaps + PVRv)
5
Q
What are some pulmonary vascular disorders?
A
- Pulmonary hypertension
- Pulmonary embolism
- Pulmonary vasculitides
- Pulmonary arteriovenous malformation
6
Q
What is the cutoff for pulmonary HTN?
A
Mean PA pressure > 25 mmHg
(recall, normal is 15 mmHg)
7
Q
How is Pulmonary HTN classified?
A
1. Pulmonary arterial hypertension (PAH)
- Toxin/drug use
- HIV
- Portal hypertension, liver cirrhosis
- Sickle Cell Disease
- Group 1 disease have specific targeted treatments*
2. Left heart disease
3. Lung diseases and/or hypoxia
- Obstructive
- Restrictive
- Chronic hypoxemia
4. Chronic thromboembolic pulmonary HTN (CTEPH)
- Persistent elevation of pulmonary P -> symptoms and heart failure
5. Unclear multifactorial mechanisms
- Sarcoidosis
8
Q
What are the structural and functional changes in pulmonary HTN?
A
Increased PVR
- Sustained vasoconstriction (muscle layer hypertrophy and permeation into other layers)
- Vascular remodeling
- In-situ thrombosis
- Increased arterial wall stiffness
9
Q
What is idiopathic Pulmonary Arterial HTN?
- Epidemiology
- Pathology
A
Epidemiology
- Uncommon
- More in women
- Mean age = 50 yo
Pathology
- Hypertrophy/fibrosis vascular bed
- In situ thrombosis
10
Q
What is the prognosis for idiopathic Pulmonary Arterial HTN?
A
- Variable
- Mean survival 2-3 yrs from time of diagnosis
- Depends on severity, cardiac function, exercise tolerance, response to vasodilators
- Non-responders: 9-18 months
- Responders w/ preserved function:- >50% for 5 yrs
11
Q
What are the clinical features of PAH?
A
- Shortness of breath
- Atypical chest pain
- Palpitations
- Cough
- Syncope (if advanced; developing RHF)
- Hemoptysis
- Hypotension
- Tachycardia
- Atrial arrhythmias
- Loud P2
- Tricuspid regurgitation murmur
- JVD
- Signs and symptoms of cor pulmonale (RHF)
12
Q
Case)
- 45 yo female with worsening SOB
- Chest pain, orthopnea, PND What is seen on her CXR?
A
- Don’t see infiltrate, pneumonia, fibrosis
- Preserved lung structure/anatomy
Heart seems somewhat abnormal:
- Large pulmonary artery indicative of pulmonary HTN
13
Q
What is seen of echocardiogram of pulmonary HTN?
A
- Small LV cavity; normal LV ejection fraction
- Severe RV dilatation, severely reduced RV global systolic function
- PA systolic pressure estimate 105-110 mmHg
- No interatrial septal defect
14
Q
What does the evaluation of suspected pulmonary HTN look like?
A
- ECHO to screen for PH and r/o primary cardiac disease
- PFT to r/o primary lung disease (esp. COPD) and restrictive lung disease
- Spiral CT (possible angiogram) to r/o pulmonary vascular disease (thromboembolic disease, vasculitis)
- Right heart cath: Pulmonary artery pressure, PCWP, hemodynamics
15
Q
What is the treatment for PAH (pulmonary HTN in general?) ?
A
- Optimize therapy for related diseases
- Supportive (O2, anticoagulation, diuretics, digoxin)
- Targeted therapy - Surgical
16
Q
What are targeted therapies for PAH?
A
- Prostacyclins
- Endothelin receptor antagonist
- NO pathway drugs
- Soluble guanylate cyclase stimulators
17
Q
What are characteristics of prostacyclins for PAH treatment?
Examples (probably don’t need to name)?
A
Vasodilatory, antiplatelet, antiproliferative
- Berapost (PO)
- Epoprostenol (IV)
- Iloprost (inhaled)
- Treprostinil (SQ, IV, inhaled, PO)
18
Q
What are characteristics of endothelin receptor antagonists for PAH treatment?
Examples (probably don’t need to name)?
A
Blocks receptor for ET-1, a potent vasoconstrictor and mitogen
- Bosentan (PO)
- Ambrisentan (PO)
- Sitaxsentan
19
Q
What are examples of NOs for PAH treatment (probably don’t need to name)?
A
- Phosphodiesterase inhibitors: Sildenafil/Tadalafil
- Inhaled NO
- Dipyridamole
20
Q
Name soluble guanylate cyclase stimulators (probably don’t need to name)?
A
Riociguat
21
Q
What are surgical therapies for PAH?
A
Lung transplantation
- Double lung transplantation typically
- Heart-lung if PAH secondary to congenital heart disorders
Atrial septostomy
- Reduces RVEDP, improves cardiac index at expense of decreased PaO2
- Bridge to transplantation
Pulmonary endarterectomy for CTEPH
22
Q
What is cor pulmonale?
- Cause
- Signs
A
- RV hypertrophy (and ultimately resulting in right heart failure) 2ndary to increased PVR
- Most commonly results from chronic pulmonary diseases (esp. COPD) that affect pulmonary vasculature.
- Signs:
- Hepatojugular reflux
- Lower extremity edema
- Pulsatile liver
- Tricuspid regurgitation
- Ascites
23
Q
What is the treatment for cor pulmonale?
A
- Treat underlying cause(COPD, etc.)
- Minimize vasoconstriction, vasodilate (O2),
- Improve cardiac output w/rhythm control and contraction
24
Q
Epidemiology of PE/DVT?
A
- Venous thromboembolism is a major medical problem
- > 5 million DVT cases annually
- Of these, 650,000 develop pulmonary embolism (PE)
- Of pts with PE, 100,000 die annually
- Not uncommon cause of death in acute care hospital setting
- > 70% of pts that die of PE are not suspected before death; maintain a high index of suspicion and pursue the diagnosis when warranted
25
What are causes of pulmonary embolism?
- Thrombus
- Fat (occurs in long bone fractures)
- Tumors
- Trophoblast
- Air (catheter placement, scuba diving)
- Amniotic fluid
26
What is VIrchow's triad?
1. Venous stasis
2. Intimal injury
3. Altered coagulation
27
What are the risk factors for thrombosis?
- Age \> 70 yo
- Obesity
- Sedentary/Bed rest
- Trauma
- Chronically ill
- Pelvic surgery/trauma
- Prolonged anesthesia (\>1 hour)
- Surgery of lower extremities
- Hip fracture/replacement
- Pregnancy/postpartum
- Right ventricular failure
- Oral contraceptives (5-10 fold increase)
- Underlying malignancy (Trousseau’s syndrome)
- Inherited/acquired deficiency of naturally
* occurring anticoagulants:resistance to activated protein C (Factor V Leiden)
* Prothrombin gene mutation
* protein C deficiency
* protein S deficiency
* Antiphospholipid antibody syndrome
* Anti-thrombin III deficiency
* Hyperhomocysteinemia
28
What are symptoms of DVT?
- Pain
- Tenderness
- Swelling
- (+) Homan's sign: dorsiflexion of foot/ankle -\> pain
29
What are the symptoms and findings of pulmonary embolism?
_Symptoms_
- Dyspnea
- Impending doom
- Palpitations (tachycardia)
- Hemoptysis and pleuritic chest pain are signs of infarction (uncommon, 20% of patients with significant cardiopulmonary disease)
_Findings_
- Tachypnea
- Tachycardia
- Low grade fever
- With massive embolism
- fixed split of S2, and S3 or S4, dilated neck veins, and cyanosis, hypotension
30
What is the diagnostic process of DVT?
**- Contrast venography**: Gold standard, only accurate method in asymptomatic individuals.
**- IPG**: Serial negative IPG or US is comparable in accuracy to negative venography in patients with suspected DVT
**- Compression ultrasonagraphy\***: Often the diagnostic modality of choice. The sensitivity and specificity approach 97%-98% for symptomatic patients.
- **MRI**: High sensitivity and specificity, expensive
**- D-dimer:** Low levels of plasma D-dimer (under 500 ng/mL) by ELISA technique may have a high negative predictive value
31
**T/F:** You can get DVT in upper extremity veins?
True!
32
What is seen on CXR for someone with DVT?
- Localized oligemia -\> Westermark sign:
- Hampton's hump
- Consolidation (infarct)
- Usual report is "normal"
33
What is seen on EKG for someone with DVT?
- Tachycardia
- Right axis deviation (right sided strain)
- New onset atrial fib
34
What is S1Q3T3?
The classic finding; "not common, but always talked about"
35
What are the diagnostic tests on PE of someone with DVT?
**ABG’s: increased A-a difference;**
**Pa02 may be above 80;**
**C02 usually decreased**
Remember to calculate the A-a diff
- A-a difference is usually increased
- Alveolar gas equation
- [FIO2(PB-PH20) – PaC02/R] – Pa02
- [150-PaC02/0.8] - Pa02
36
What is the Wells Diagnostic Scoring? Considerations?
_Predicts clinical likelihood of PE_
- Signs/symptoms of DVT (3)
- Another diagnosis less likely than DVT (3)
- HR \> 100 (1.5)
- Immobilization/surgery within 4 wks (1.5)
- Previous DVT/PE (1.5)
- Hemotpysis (1)
- Malignancy (active or treated within 6 mo) (1)
**Pre test probability: ≤ 2 low; 2-6 Moderate; \>6 High**
37
What is the diagnostic approach?
- Chest CT with contrast, PE protocol
- Less commonly VQ scan
- Rarely, pulmonary angiogram
- If negative or inconclusive and clinical suspicion present….
--\>further diagnostic testing
- Evaluate for DVT or perform other diagnostic test.
38
Pros/cons of diagnosing PE with helical/spiral CT?
**Helical/spiral CT:**
_Advantages_
- Specificity
- Availability
- Safety
- Relatively rapid
- Other diagnosis
- Advancing technology
_Limitations:_
- Expense
- Not portable
- Need contrast
- Poor visualization in some areas
- Contraindication: renal insufficiency/allergy
- Reader expertise
39
What is a ventilation perfusion scan (VQ scan)?
- Nuclear medicine test to evaluate ventilation (V) and perfusion (Q)
- “Matched” defects
- non-diagnostic, compare to x-ray
- “Unmatched” defects
- suggestive of perfusion abnormality
40
Describe Pulmonary Angiogram
- Process
- Purpose
- Commonality
- Intra-arterial dye
- Directly assesses vasculature
- Rarely used now
41
What do each of these gross pictures show?
1- Embolus with infarct
2- Saddle embolus
3- Infarct
42
How can DVT be prevented?
Based on level of risk and risk of bleeding
- **Low**: (under 10% VTE without prophylaxis) early ambulation only
- **Moderate**: (risk of VTE 40%): most general surgical pts or med pts at bedrest; give LMWH, LDUH, fondaparinux or mechanical if bleeding risk high
- **High**: orthopedic, major trauma, spinal cord injury; give LMWH, fondaparinux, rivoroxaban, Vit K antagonist; mechanical if bleeding risk high
43
How to treat PE?
**Anticoagulation**
- Acute
* Weight-adjusted heparin IV
* LMWH
- Long term
* Warfarin
* Oral factor XA inhibitors
* LMWH Thrombolysis
**Embolectomy**
**IVC Filter**
44
What is HIT?
- Mechanism
- Labs
Heparin Induced Thrombocytopenia
- Immune-mediated drug reaction
- Results in platelet removal -\> **thrombocytopenia** (most common, 90%)
- Results in platelet aggregation and release of procoagulant microparticles (**thrombosis**)
- Defined by presence of heparin-reactive antibodies to **platelet factor 4** (HIT Abs)
45
What are complications of HIT?
- Deep vein thrombosis
- Pulmonary embolism
- Myocardial infarction
- Occlusion of limb arteries (possibly resulting in amputation)
- Cerebrovascular accidents (stroke, TIA)
- Skin necrosis
- End-organ damage (e.g., adrenal, bowel, spleen, gallbladder or hepatic infarction; renal failure)
- Death
46
What is Warfarin?
- Mechanism
- Dynamics/activity
- Metabolism
- ASEs
- Management
- Reversal
- Antagonizes Vitamin K dependent factors (Factors 2, 7, 9, and 10 as well as protein C and protein S)
- Delayed effect based on the shortest 1/2 life (Factor 7: 6 hrs); 18-24 hrs
- Crosses placenta; CONTRAINDICATED in pregnancy
- Numerous drug-drug, drug-disease (liver), and drug-food (Vit K) interactions
- Careful monitoring of INR (standardized msmt of PT); usual targeted range is 2-3
- Reversal with Vitamin K (mild) or FFP
47
What things diminish Warfarin effect? INR level?
**INR** level will be **low**
- **Inhibits drug absorption**: Cholestyramine
- **Increases metabolism (enhance p450)**: Barbiturates, Carbamazepine, Phenytoin, Rifampin
- **Vitamin K**: foods, esp leafy greens
48
What things enhance Warfarin effect? INR level?
**INR** will be **high**
**- Displaces from albumin:** choral hydrate
**- Decreased metabolism (inhibits p450)**: Amiodarone, clopidogrel, ethanol, fluconazole, fluoxetine, metronidazole, sulfamethoxazole
**- Eliminate gut bacteria and decrease K**: Broad-spectrum antibiotics
49
What should the duration of therapy be for ?? (HIT?) (PE?)
- 3 months in patients with transient risk factors
- May be life long in patients with recurrent thrombosis or continued risk factors (e.g. malignancy, hypercoagulable state)
50
What is an IVC filter? What is it used to treat?
IVC filter: treatment of PE
- Patients with **massive PE who could not tolerate a recurrence**
- Patients with c**ontraindications to anticoagulation**
- Recommended for repeat PE despite anticoagulation or when anticoagulation is contraindicated
- Filter is a wire apparatus inserted through a catheter in the inferior vena cava to prevent PE
- Filter may be removed
51
What are other therapies for PE?
- **Thrombolytic**: reserved for patients with massive PE (clinically severe, severe cardio pulmonary compromise, i.e. hemodynamic instability, hypoxemia, RV dysfunction despite resuscitative efforts).
- **Embolectomy**
52
Summary of Pulmonary HTN
- Various causes and important to classify based on WHO grouping
- Treatment will be guided by etiology
- Progressive shortness of breath, loud P2
- Idiopathic Pulmonary Arterial HTN pathology is medial hypertrophy and intimal fibrosis
- Treatment with pulmonary vasodilators and lung transplant
53
Summary of DVT/PE
- Risk factors of prolonged immobility, hypercoagulable states etc.
- Symptoms of leg swelling, pain in DVT
- Sudden onset SOB+- pleuritic chest pain with hypoxemia in PE
- DVT diagnosed with venous compression ultrasonography
- PE diagnosed by spiral CT or V/Q scan
54
Summary of Pulmonary Vascular Disorders
- Treatment with anticoagulation (UFH, LMWH or Warfarin); Less commonly IVC filter, thrombolysis, embolectomy
- Major complications of heparin is Heparin induced thrombocytopenia
- Major complication of Warfarin is drug-drug interactions
