Pulmonary Vascular Diseases and Cor Pulmonale Flashcards
Major Role of Pulmonary Circulation:
Bring blood into close proximity with air so that gas exchange can occur
Consists of arteries, capillaries, and veins
It is a High Volume, Low Pressure System
Pulmonary Circulation
Major Role of bronchial circulation
Supply blood to airways
1/3 blood flow through the bronchial circulation empties into the azygos vein
2/3 of blood flow through the bronchial circulation empties into the pulmonary capillaries
Low Volume; High Pressure system
Bronchial Circulation
Venous Thromboembolic Disease
Includes deep vein thrombosis and pulmonary emboli
abrupt onset of dyspnea, Right pleuritic pain
Diagnosis of DVT
Venography
Impedance plethysmography
Compression ultrasonagrophy
Standard diagnostic tool, injection of dye
Venography
Non invasive, sensitive and specific
Impedence plethysmography
Non-invasive, sensitive and specific. Test of choice for diagnosis of DVT
Compression Ultasonography
Most common pulmonary disorder among hospitalized patients
Pulmonary Embolism
Pathogenesis of Pulmonary Embolism
Most often detached portions of venous thrombi that dislodge andbtravel through the central veins to the pulmonary arteries
Major sources of clinically imporatant pulmonary emboli (>50% originate below the knee)
Femoral, iliac, and pelvic veins
Virchows triad
Endothelial injury
Stasis of flow
Activation of clotting
Pulmonary embolism is most frequent in…..
Lower lobes, and right lung
Emboli obstruct blood flow
Alveolar dead space Bronchoconstriction Decreased surfactant production Hypoxemia Pulmonary hypertension Shock (saddle embolus)
VE
equal to the sum of alveolar ventilation and dead space ventilation
Clinical features of Pulmonary Embolism
No specific signs or symptoms
Anticoagulation is started on suspicion of PE and stopped only when PE is ruled out
Most common symptom of PE
Dyspnea
calf pain on dorsiflexion of foot
Homan’s sign
Effects of pulmonary Embolism
Increased pulmonary vascular resistance
Impaired gas exchange
alveolar hyperventilation
Increased airway resitance
Decreased pulmonary compliance
Increased pulmonary vascular resistance
vascular obstruction or neurohumoral agents like serotonin
Impaired gas exchange
increase alvolar dead space from vascular obstruction and hypoxemia from alveolar hypoventilation in non-obstructive lung
Alveolar hyperventilation
reflex stimulation or irritant receptors
Increased airway resistance
Bronchoconstriction
Decreased pulmonary compliance
Lung edema, lung hemorrhage or loss of surfactant
CXR of PE
Hampton’s Hump
Peripheral wedge-shaped opacification abutting the pleura. SIgnifying pulmonary infarction distal to a pulmonary embolism
Westermark’s sign
-dilatation of pulmonary vessels proximal to embolism along with collapse of distal with a sharp cut-off
Ventilation Perfusion Scans
useful if Normal
Angiogram of PE
Pulmonary angiography is the gold standard
CT angiography
detect alternative pulmonary abnormalities that may explain the patient’s symptoms and signs
Pulmonary Embolism ECG and ABG
ECG rules out other inflammatory lefe threathening conditions
Tachycardia, ST depression most common
ABG findings most commonly show hypoxemia and hypocapnia
15-25% have PO2 >80mmHg
D-dimers
Level <500 mg/L rules out PE
Physiologic Effects of Pulmonary Embolism
Hypoxemia
- INcreased blood flow through regions of physiologic shunt or poor V/Q matching
Landmark study in the clinical probability of venous thromboembolism occuring
PIOPED study
V/Q scan
IV push of radioisotope-tagged albumin and radio-labeled gas in inhaled
Gamma radiation produced by radioisotopes show distribution of blood flow and ventilation
Pulmonary Embolism Management
Use Knee-high 30-400 mm elastic stocking on affected legs
Prevents further clot formation and clot being brought further into the system
Pulmonary Embolism and DVT management
Continue injected anticoagulant and hospitalization until patient is saafely assured
Prophylaxis of DVT
Heparin or fondaparinux is most commonly used
What type of heparin is used?
unfractionated
Management DVT
Heparin
Thrombolytic Agents
Management of PE
Preserving oxygenation and circulation are paramount. If circulation is impaired, consider clot lysis, drug or mechanical
Similar regimen to DVT
-first line heparin followed by oral coumarin
Supportive measures include:
Oxygen therapy
Analgesia
Hypotension and shock are treated with vasopressors and fluids
If patients are stable within 3 days of PE
they can be safely transferred out, as long as the condition that led to clot formation has been resolved
Mean pulmonary artery pressure >25 mmHg at rest or MPAP >30mmHg with exercise, with increased pulmonary vascular resistance and normal left ventricular function
Pulmonary arterial hypertension
Associated with congenital heart disease, collagen vascular disease, liver cirrhosis
Pulmonary Hyertension
Increased BP in the pulmonary arteries
PAH
Increased BP in the pulmonary veins
PVH
A blood clot breaks off from a deep vein
PE
A progressive disorder, primarly affects small pulmonary arterioles, Proliferation and remodeling of endothelial and smooth muscle cells
PAH
mPAP >25 mmHg
mPAP >30 mmHg
Devolopment of IPAH
Genetic Predisposition probably required
Follows insult to arterial endothelium
Damage results in vasoconstriction
Maybe caused by abnormal transport of potassium and calcium
Clinical Features of PAH
Dyspnea (60%)
Angina (50%)
Syncope (8%)
Others: Cough, hemoptysis, hoarseness and reynaud’s phenomenon
Management of PAH
Supplemental Oxygen (SaO2>90%)
Anticoagulation with coumadin
Adjust to keep INR-2
Vasodilators (Ca Channel Blockers)
May usedigoxin and diuretics to manage side effects
NO is preferred
Very short half life
Does not affect CO
Enhances V/Q mismatching
Pulmonary Hypertension COPD
Alveolar hypoxia causes vasoconstriction and eventually medial hypertrophy, fibrosis and lumen narrowing
Leads to HPN
Severity of COPD with severity of HPN
Symptoms of PAH
Slowly progressive shortness of breath
As the condition worsens, chest pain or fainting (syncope) with exertion can occur
Pulmonary Venous Hypertension
Shortens of breath, due to the CHF - shortness of breath may be worse while lying flat, when BP is uncontrolled, or when extra fluid is present
Clinical Classification of Pulmonay Hypertension
Group 1: Pulmonary arterial hypertension
Group 2: Pulmonary hypertension due to left heart disease
Group 3: Pulmonary hypertension due to lung disease and/or hypoxia
Group 4:
Chronic thromboembolic pulmonary hypertension (CTEPH)
Group 5: Pulmonary hypertension with unclear multifactorial mechanism
hypertrophy of the RV resulting from diseases affecting the function and or structure of the lung, except when these pulmonary alterations are the result of diseaealterations are the result of disease that primarily affect the left side of the heart or congenital heart disease
COR PULMONALE
Etiologies of PAH
Lungs and Airways
Vascular Occlusion
Abnormal Respiratory Control
Etiology of Cor pulmonale (Thoracic Cage)
Kyphosis >180 degrees
Scoliosis >120 degrees
Thoracoplasty
Pleural fibrosis
Pathologic features of Cor Pulmonale
Lung: consistent with specific diseases
Common feature: Microvascular hypertrophy
Hallmark: RVH
- 60-200 g>0.5 cm
- RV/LV <2.5
LVH
Carotid body hypertrophy
Diagnostic Tests for Cor Pulmonale
CXR: depends on underlying lung condition but usually shows enlarged main PA segment (>16mm)
ECG: P pulmonale (peaked p wave), RA enlargement, RVH
Doppler Echocardiography: RVH, poor RV contactility with low EF, evidences of moderate to severe PH
Cor Pulmonale: Differential Diagnosis
Cor pulmonale from primary underlying lung disease such as COPD, Sleep disordered breathing
vs
Cardiac Diseases such as RHD with MS, COngenital Heart disease with systemic-pulmonary shunt
Therapeutic Strategies for Cor Pulmonale
Diet and lifestyle
Interventions
Interventions in cor pulmonale
Treat underlying cause
Continuous oxygen 2-3L/mn
Diuretics
Phlebotomy
Digoxin
Pulmonary vasodilators
beta adrenergic agents
Reduce ventilation/perfusion imbalance
