Pulmonary vascular disease (Pulmonary hypertension) Flashcards
What is pumonary hypertension?
Defined as a mean pulmonary artery pressure (mPAP) of >25 mmHg at rest as measured on right heart catheterization.
What is normal pulmonary blood pressure at rest?
Approx 25 mmHg
What is regarded as mild PHT?
Pulmonary pressure between 25-45 mmHg
What is regarded as moderate PHT?
46-65 mmHg
What is regarded as severe PHT?
>65 mmHg
Which sex is PHT more common in?
Female
What are the main classification groups used in in PHT?
- Pulmonary arterial hypertension
- PHT due to left heart disease
- PHT due to lung disease +/-hypoxia
- PHT due to thromboembolism
- PHT due to Multifactorial mechanisms
What are causes of pulmonary arterial hypertension?
- Idiopathic
- Heritable
- Drug
- Persistent PH in newborns
- Connective tissue disease
What are causes of PHT due to left heart disease?
- Systolic Dysfunction
- Diastolic dysfunction
- Valvular Disease
What are causes of PHT due to lung disease +/- hypoxia?
- COPD
- Interstitial LD
- Other diseases with restrictive/obstructive pattern
- Alveolar hypoventilation disorders
- Chronic high altitude exposure
- Sleep apnoea
In terms of pulmonary vessel loss, what percentage loss needs to be exceeded for resting pulmonary arterial pressure to increase?
60%
What are symptoms of PHT?
Early
- Unexplained SOB
- Fatigue
- Syncope
- Chest tightness
- (Haemoptysis)
Late
- Ankle swelling
- RUQ pain
What are signs of PHT?
- Loud P2
- Right Ventricular Heave
- Pulmonary Flow murmur (Ejection systolic)
- Murmers increased by inspiration
- Low gas transfers/desaturation/ hypoxia out of keeping with spirometry
- Signs of RHF - backing up into the system
Why do you get a loud P2 in PHT?
Increased pulmonary hypertension of any cause may slam shut the pulmonary valve and cause a louder than normal pulmonary component of the second heart sound.
Why might you get a right ventricular heave in PHT?
Increased pressure load causes right ventricular hypertrophy and displacement of the right ventricle closer to the chest wall.
What are the mechanisms that contribute to dyspnoea in primary PHT?
- Relative hypoperfusion of ventilated alveoli leading to increased V/Q mismatch and increased alveolar dead space
- Lactic acidemia
- Hypoxaemia
- Inability to increase pulmonary blood flow (and therefore systemic blood flow) to meet exercise oxygen demand.
What might you see on CXR in someone with PHT?
- Enlargement of the pulmonary arteries
- Marked tapering (pruning) of peripheral arteries
- Lucent lung fields
- Right atrial and ventricular enlargement.
