20 - Pulmonary Vascular Disease Flashcards
What factors influence pulmonary vascular resistance?
- recruitment and distension
- lung volume
- intrathoracic pressure
- increased viscosity
- decreased vessel radius
How much pulmonary vascular destruction needs to occur before pulmonary hypertension occurs at rest/
50-70%
What is the definition of pulmonary arterial hypertension? What is the definition of pulmonary venous hypertension?
Arterial - mean arterial pressure ≥ 25 mmHg at rest, with a pulmonary capillary wedge pressure ≤ 15 mmHg (pre-capillary)
Venous - pulmonary capillary wedge pressure > 15 mmHg (post-capillary)
How does hypoxia cause pulmonary hypertension?
- vasoconstriction
- remodeling (smooth muscle where it normally doesn’t belong)
What are the clinical findings of pulmonary hypertension?
- dyspnea
- syncope
- lower extremity edema
- JVD
- tricuspid regurgitation murmur
- right ventricular heave
- loud P2 (from pulmonic closure)
Cor pulmonale is [right/left]-sided heart failure from lung disease. What causes it?
Right sided
Due to increased pulmonary vascular resistance and pulmonary hypertension
What are the acute and chronic causes of cor pulmonale? Which can lead to right ventricular failure and shock?
Acute - can lead to RV failure and shock if mean PA > 40
- massive pulmonary embolism
Chronic
- idiopathic pulmonary arterial hypertension
- pulmonary hypertension secondary to COPD or IPF
What are the 5 WHO groups for pulmonary hypertension? What are their causes? Which is the most common? What are their associated PVRs and PCWPs?
1 - Pulmonary Artery Hypertension (PAH) - idopathic - connective tissue disease - HIV - cirrhosis - congenital heart disease - drug induced Precapillary, greatly increased PVR, normal PCWP
2 - Pulmonary Venous Hypertension (most common)
- left heart disease (systolic or diastolic dysfunction)
Postcapillary, normal PVR, increased PCWP
3 - Hypoxia or Lung Issue - sleep apnea - obesity hypoventilation syndrome - high altitude - COPD - IPF precapillary, increased PVR, normal PCWP
4 - Thromboembolic
Precapillary, increased PVR, normal PCWP
5 - Miscellaneous
What is the pathogenesis of pulmonary hypertension?
- imbalance between vasodilators (decreased NO and prostacyclin) and vasoconstrictors (increased thromboxane and endothelin)
- fibrinolytic defects
- increased smooth muscle proliferation in pulmonary arteries/arterioles
NO is a [vasodilator/vasoconstrictor]. It is [increased/decreased] in pulmonary hypertension.
vasodilator; decreased
Prostacyclin is a [vasodilator/vasoconstrictor]. It is [increased/decreased] in pulmonary hypertension.
vasodilator; decreased
Thromboxane is a [vasodilator/vasoconstrictor]. It is [increased/decreased] in pulmonary hypertension.
vasoconstrictor; increased
Endothelin is a [vasodilator/vasoconstrictor]. It is [increased/decreased] in pulmonary hypertension.
vasoconstrictor; increased
What mutation is associated with pulmonary hypertension? What is the result of it?
BMPR2 –> increased TGF-beta induced smooth muscle cell proliferation in pulmonary arteries/arterioles
What is the best screening test for pulmonary hypertension?
cardiac echo