Lecture 28 - Pulmonary Hypertension Flashcards
What happens during pulmonary hypertension (PH)?
The alteration in the structure and function of the pulmonary arteries - primarily not in other arteries of the body
Pulmonary artery pressure of >25 mmHg
(normally is around 15 mmHg)
What are the symptoms of pulmonary hypertension?
Non-specific symptoms: breathless, fatigue and chest pain
Symptoms develop gradually, when the disease is very advanced
What is primary PH?
PH from unknown cause
40% of cases
What is secondary PH?
PH from:
Chronic obstructive pulmonary disease (COPD ), lung conditions
Mitral valve disease
Sleep apnoea
Sickle cell anaemia
HIV
What are causes of remodelling of pulmonary arteries?
Increased pressures - altered shear stresses
Endothelial dysfunction and proliferation
Disturbed vasodilator-vasoconstrictor balance:
Nitric oxide, Prostacyclin decrease vs. Endothelin, Thromboxane increase
Describe arteriosclerosis in pulmonary arteries
Intimal and medial thickening
- Endothelial proliferation
- Intimal fibrosis
- Medial and smooth muscle cell hypertrophy
Describe atherosclerosis in pulmonary arteries
Intimal fibrosis and in situ thrombosis
- thrombosis indicates role for inflammation
What are the consequences of PH on the pulmonary system? (5)
More difficult to pump the blood into the lungs
Pulmonary Resistance increases Pulmonary Artery Pressure (PAP)
Severe bronchial obstruction (due to fibrosis and increased mucus production)
Decreased diffusion capacity for O2
Hypoxemia (decreased partial O2 pressure)
Why are changes in resistance more disastrous in the pulmonary system?
Although overall resistance and blood pressures are lower in pulmonary system, increases in pulmonary resistance result in relative larger increases in blood pressures (with more disastrous consequences)
What ventricle is affected in PH?
Right ventricle
What is the effect of cardiac remodelling in the compensated stage? (PH)
Pulmonary vascular resistance ↑
RV wall stress ↑
Compensated RV hypertrophy
RV wall stress normalized = Pulmonary vascular resistance ↑
What is the effect of cardiac remodelling in the decompensated stage? (PH)
Limit of RV hypertrophy reached
RV wall stress ↑
RV dilation
RV heart failure
LV dysfunction
In the late/end stages of Pulmonary Hypertension the end-diastolic volume:
A. of the RV is increased, and of the LV remains the same.
B. of the RV is decreased, and of the LV remains the same.
C. of the RV is increased, and of the LV is decreased.
D. of the RV is decreased, and of the LV is decreased.
C. of the RV is increased, and of the LV is decreased.
What is sildenafil and what does it do in the lung?
PDE-5 inhibitor
Relaxes smooth muscle cells, vasodilatation, selectively in lung - opposes high altitude-induced pulmonary hypertension
What can be used for the treatment of PH?
GC stimulators/activators
Endothelin receptor antagonists
Prostaglandins
PDE5-inhibitors
