9.6 Pulmonary Hypertension Flashcards
True or false: pulmonary hypertension is a disease
- False
- It is not a disease, it is a haemodynamic measurement
Pulmonary hypertension vs pulmonary artery hypertension
pulmonary arterial hypertension is a disease group within the wider haemodyanmic range of pulmonary hypertension
How do you calculate mPAP (mean Pulmonary Artery Pressure)?`
1/3 sPAP + 2/3 dPAP
What is the mPAP cutoff for pulmonary hypertension? Why is/isn’t this sufficient for a diagnosis?
- Cutoff is 20mmHg
- This is not sufficient for a diagnosis, since a wide range of other factors can influence mPAP
List some factors other than pulmonary hypertension that can increase mPAP
- Hyperviscosity
- Increased CO
- Left to right cardiac shunts
Other than evidence of mPAP >= 20, what else is needed to diagnose pulmonary arterial hypertension?
Evidence of increased pulmonary vascular resistance
What level of pulmonary vascular resistance is required to diagnose pulmonary arterial hypertension? Is this likely to be right 100% of the time?
Cutoff is >=3 Wood Units (WU)
In reality, it should probably be lower
What does pulmonary artery wedge pressure (PAWP) inform us about
- It provides an approximation of left arterial pressure, and thus left ventricular preload
- We can use it to assess for left-heart-related implications of pulmonary hypertension
List two kinds of pulmonary hypertension
- Pre-capillary (PAH)
- Isolated post-capillary (IpcPH)
Describe the mPAP, PAWP, and PVR in Pulmonary Arterial Hypertension
mPAP:> 20mmHg
PAWP: <=15mmHg (not left-heart involved, so not elevated)
PVR: >3 WU
Describe the mPAP, PAWP, and PVR in Isolated, post-capillary Pulmonary Hypertension (IpcPH)
mPAP: >20mmHg
PAWP: > 15mmHg (left-heart involvement)
PVR: <3 WU
Describe the changes that occur to pulmonary arteries in Pulmonary Arterial Hypertension
- Intimal fibrosis
- Endothelial proliferation
- SMC hyperplasia and hypertrophy
Describe the changes in cardiac output, pulmonary vascular resistance, and pulmonary arterial pressure that occur during the worsening of PAH
- PVR increases, and PAP increases to prevent CO from falling too much (check with Ohm’s Law)
- Eventually, heart begins to fail, and PAP decreases, causing CO to decrease
What is the most common cause of pulmonary artery hypertension? What are some examples of this?
- Left heart disease
- HFrEF/HFpEf
- Valvular disease
- Congenital abnormalities
Other than left-sided heart disease, list some less common causes of pulmonary hypertension
- Lung disease/hypoxia
- Pulmonary artery obstructions (e.g. clot)
List some causes of pulmonary arterial hypertension
- Idiopathic
- Heritable
- Drug/toxin-associated
- Connective tissue disease
- Calcium channel blockers
Presenting symptoms of pulmonary hypertension
- Dyspnoea (usually during exercise)
- Fatigue
- Exercise intolerance
- Syncope on exertion
- Anginal chest pain
What symptoms of disease progression may be seen in pulmonary hypertension?
Right heart failure: Raised JVP, and peripheral oedema
Describe the physical exam results of a patient with pulmonary hypertension
Typically normal; maybe 2nd pulmonary heart sound accentuated or RV heave in late-stage
Blood-based investigations for patient with suspected pulmonary hypertension
- FBC (anaemia)
- EUC (renal hypertension)
- LFTs (Right heart failure)
- NT-proBNP/BNP (Right heart failure)
- Autoimmune screen (connective tissue disorder)
What ECG signs might indicate pulmonary hypertension?
- Right ventricular hypertrophy
- Right axis deviation
What is the main screening tool for pulmonary hypertension? How does it work?
Echocardiography. By passing a doppler catheter through the tricuspid valve, you can estimate right ventricular systolic pressure
Does a negative echocardiogram definitively exclude pulmonary hypertension?
No
In the context of pulmonary hypertension, what are ventilation perfusion scans good at detecting?
They are good at detecting chronic thromboembolic pulmonary hypertension
Left heart disease is associated with pulmonary hypertension. What are some risk factors of left heart disease
- Systemic hypertension
- Diabetes
- Obesity
- Older age
- Atrial fibrillation
CT chests are used to screen for pulmonary hypertension. What are some features that indicate this diagnosis on CT?
- RV dilation
- RA dilation
- HRCT signs of lung disease
What is the purpose of pulmonary function tests in screening for pulmonary hypertension
To assess for any other lung disease that may be comorbid/contributing to lung disease
Describe gold-standard diagnosis of pulmonary hypertension
- Right-heart catheterisation
- Measures RA pressure, RV pressure, pulmonary arterial pressure, PAWP, and cardiac output
What values can we calculate as a result of right-heart catheterisation?
- Transpulmonary gradient (difference between mPAP and PAWP)
- Pulmonary vascular resistance (TPG/CO)
- Cardiac index (CO/Body surface area)
Describe the four functional classes of pulmonary hypertension
FC I: Asymptomatic
FC II: Limited to moderate/high exertion
FC III: Limited day-to-day
FC IV: Bed-ridden
What are the three drug pathways for pulmonary hypertension treatment?
- Endothelin pathway (constrictor)
- Nitric oxide pathway (dilator)
- Prostacyclin pathway (dilator)
List three endothelin receptor antagonists (hint: what is the suffix?)
- Bosentan
- Ambrisentan
- Macitentan
List three drugs that act on the nitric oxide pathway to treat pulmonary hypertension
- Sildenafil
- Tadalafil
- Riociguat
A patient with pulmonary hypertensionf is responsive to inhaled vasodilators. What drug should we give them>
Try them on calcium channel blockers
During management of pulmonary hypertension, patients are started on two drugs. If they still remain at high risk, what other treatments may be considered?
- Additional IV drugs
- Lung transplant if all else fails
Some patients may not be suited to IV pulmonary hypertension therapy. Why?
- Don’t want IV therapy
- Elderly
- IV drug user (don’t want cannula)
