Pulmonary Arterial Hypertension Flashcards
What is pulmonary hypertension definition?
Definition: mPAP ≥ 25mmHg
Describe the 5 different WHO groups of PH
- Pulmonary Arterial Hypertension (PAH)
- Left-heart related
- Lung/hypoxia related
- CTEPH
- Other
- Haem disorders, sarcoidosis
Explain WHO Group 1 PH
- Idiopathic or heritable
- BMPR2, ALK-1, SMAD9
- Associated
- Connective Tissue Disorders (scleroderma)
- HIV, Schistosomiasis
Explain WHO Group 2 PH and give examples
PH with left heart disease
LV sysotlic or diastolic dysfunction, valvular disease, cardiomyopathies
Explain WHO Group 3 PH and give examples
PH with lung disease and/or chronic hypoxia
COPD, ILD, OSA, high altitude
Explain WHO Group 4 PH
Pulmonary Hypertension due to blood clots in the lungs
Chronic thromboembolic pulmonary hypertension
Explain WHO Group 5 PH and give examples
PH with unclear and multi-factorial mechanisms
Hameatological disorders, sarcoidosis, histiocytosis
With what equipment is pulmonary hypertension diagnosed and how is this performed
Swan-Ganz Catheter - inserted through a vein (femoral, internal jugular, subclavian) follows through to RA, to RV then to the pulmonary artery.
Catheter provides the Mean Pulmonary Artery Pressure - a echocardiogram would provide a systolic blood pressure
How do you differentiate between the different WHO PH Groups
PAWP >15mmHg = Group 2 (PH with LHD)
PAWP <15mmHg = Group 1, 3, 4, 5
PAWP = Pulmonary artery wedge pressure
Which WHO Group is treatable and by which therapy
Group 1 treated with pulmonary vasodilators
Breifly outline possible pathogenesis of PAH
Considered a smooth muscle and endothelial cell disease
Pathogenesis based on a balance of vasodilators/anti-proliferative agents vs vasoconstrictor/proliferative agents
PH is based on balance of vasodilator/anti-proliferative vs vasoconstrictor/proliferative agents. What does an imbalance of these factors lead to? (4)
- Vascular remodelling
- Increased vascular tone
- Prothrombotic abnormalities
- Autoimmunity
Ulitmately = Excessive vasoconstriction
IPAH has a genetic aetiology too. There is belief that there is a two-hit hypothesis associated with PAH. Explain what is meant by this.
Patient can have a mutation making them genetically susceptible to PAH.
They will not display symptoms until another hit (virus, inflammation, hypoxia, drugs) occurs (repeated insults)
BMPR2, SMAD9, ALK1
There has been interest into redfining the definition for pulmonary hypertension as the current definition (mPAP ≥ _____) was chosen arbitrarily. Statsitical methods have shown that having mPAP of 20 mmHg is abnormal and yet we don’t define this as pulmonary HTN. Data also shows that pressures of 19-24 mmHg show poor _____ and _____ chance of ______ compared to normal (18mmHg). There have also been cases wher pathology showed signs of remodelling at mPAP 22mmHg
There has been interest into redfining the definition for pulmonary hypertension as the current definition (mPAP ≥ 25) was chosen arbitrarily. Statsitical methods have shown that having mPAP of 20 mmHg is abnormal and yet we don’t define this as pulmonary HTN. Data also shows that pressures of 19-24 mmHg show poor prognosis and decreased chance of survival compared to normal (18mmHg). There have also been cases wher pathology showed signs of remodelling at mPAP 22mmHg
Describe the consequences of pulmonary artery hypertension
Raised pulmonary artery pressure
Leads to vascular proliferation and arterial wall thickening.
Vasoconstriction and in situ thrombosis also occurs
There is ↑pulmonary vascular resistance
Leads to RVH and dilatation resulting in RVF
40% mortality per year if untreated - there is increased wall thickening due to Laplace’s law (T = (P x r)/2h)
Describe a characteristic feature of group I pulmonary hypertension (PAH)
Plexiform lesions (capillary like network)
Differentiate between IPAH and PH with emphysema
IPAH characterised by proliferating vessels, smooth muscle hypertrophy
PH with emphysema - there is destruction of vessels
Implications in lung studies looking at PVR as primary end point as there is no continuity between the right side of heart and pulmonary artery in terms of pressure. The structural changes in emphysema negates pressure measurments
What determines the pulmonary vascular resistance
The small vessels of the lungs (capillaries)
Define Pulmonary hypertension
mPAP ≥ 25 mmHg
Define pulmonary arterial hypertension
mPAP ≥ 25 mmHg
PCWP ≤ 15 mmHg
PVR ≥ 3 WU
Define pulmonary venous hypertension (post-capillary HTN)
mPAP ≥ 25 mmHg
PCWP > 15 mmHg
Raised PVR leads to what cardiac consequence?
Raised PVR = Right Ventricle dysfunction
The ability of RV to cope determines the survival of the patient
IPAH RV have more collagen deposits compared to a congenital cardiomypoathy - reason why IPAH patients die more compared to congenital heart disease
What is the consequence of a failing right ventricle?
- ↓Oxygen supply
- ↓Coronary perfusion pressure
- ↑Oxygen demand
- ↓Cardiac Output
- ↑RV distension
- ↓LV filling
The characteristic symptoms of PH present late: (6)
Tachypnoea/Arrythmia
Raised JVP (a wave or v wave)
RV heave
Loud 2nd heart sound
RHF
Hepatomegaly
Describe the 4 WHO Functional Classes of PH (symptoms)
- Class I
- Symptoms do not limit phycial activity
- Class II
- Comfortqable at rest, symptoms with ordinary activity
- Class III
- Comfortable at rest, symptoms with minimal activity
- Class IV
- Unable to carry out activity - symptoms at rest (RHF)
A _____ WHO functional class indicates severity of disease. Untreated median survival of PH is _____ years (2011). Mortality is subtype dependent and survival is dependent on the _____ _____ ability to adapt to the high pressures.
A higher WHO functional class indicates severity of disease. Untreated median survival of PH is 7 years (2011). Mortality is subtype dependent and survival is dependent on the Right ventircle’s ability to adapt to the high pressures.
What is the first-line screening method for PAH
Estimated systolic PAP on an echocardiogram
- Derived from tricuspid regurgitant velocity*
- TR Velocity 2.8 m/s*
- Insufficient TR and poor echo windows lead to inability to estimate TR/sPAP*
Name some clinical investigations to help diagnose PH
- TFTs and Autoimmune screen
- BNP (ventricular myocytes)
- ECG
- RVH ± strain pattern
- Arrythmias
- CXR
- Cardiomegaly (RA border)
- Large, dilated proximal pulmonary arteries
- Echocardiogram
- Estimated sPAP
- TR Velocity 2.8 m/s
- VQ
- CTPA
Describe the findings seen on a CT
Dilated central pulmonary artery
RV chamber dimensions
Septal shift
Mosaicism (in lung, neovascularisation)
Pulmonary Veno-Occlusive Disease (PVOD) is a rare form of pulmonary HTN, featuring blockade of small veins in the lung. What is the triad for PVOD
- Interlobular septal thickening
- Pleural Effusions
- ?Nodes
Describe the management of PAH
- MDT approach
- Cardioresp consultants
- Specialist nurses
- Pharmacists
- Radiologists
- General Measures
- Warfarin
- Oxygen
- Diuretics (volume control)
- Pharmacology
- CCBs
- ET-1R antagonists (severe SE, only in severe)
- Prostanoid therapy (good, but SE, CI)
- PDE inhbitors (sildenafil)
- Lung Transplant
Name some determinants of prognosis in PAH
RV failure
Symptom progression
Syncope
WHO FC
6MWT
Exercise Test
BMP levels
Echocardioaphic findings
Haemodynamics
