Pulmonary Hypertension

Question 1

Define pulmonary hypertension.

Answer 1

Increased mean pulmonary arterial pressure (PAP) ≥25 mm Hg at rest assessed by right heart catheterisation

Question 2

What are the five classes of pulmonary hypertension?

Answer 2

1. Pulmonary arterial hypertension e.g. associated with drugs, connective tissue disease, HIV, portal hypertension of congenital heart disease
2. PH due to left heart disease e.g. HFpEF and HFrEF, valvular disease
3. PH due to lung disease +/- hypoxia e.g. obstructive/restrictive lung disease, hypoxia, developmental lung disease
4. PH due to pulmonary artery obstruction e.g. chronic thromboembolic PH
5. PH with unclear/multifactorial mechanisms e.g. haematological disorders, systemic and metabolic disorders

Question 3

What is the most common cause of pulmonary hypertension?

Answer 3

Class 2 - left-sided heart failure

Question 4

What is cor pulmonale?

Answer 4

Right heart failure caused by chronic pulmonary arterial hypertension

Question 5

How common is pulmonary hypertension?

Answer 5

Idiopathic PAH is rare

More common in severe respiratory and cardiac disease, occurring in 18-50% of patients assessed for transplantation or lung volume reduction surgery

Up to 4% develop PH after acute PE

Question 6

Which pulmonary vascular conditions cause chronic arterial hypertension?

Answer 6

Pulmonary vascular disease

• Pulmonary emboli
• Pulmonary vasculitis
• Primary pulmonary hypertension
• ARDS
• Sickle-cell disease
• Parasite infestation.

Question 7

What is idiopathic pulmonary arterial hypertension?

Answer 7

Idiopathic pulmonary arterieal hypertension is rare and defined as sustained raised PAP and pulmonary vascular resistance, with normal PAWP in absence of known cause.

*PAWP = pulmonary artery wedge pressure

Question 8

What are the signs and symptoms of pulmonary hypertension?

Answer 8

• Exertional dyspnoea
• Fatigue
• Symptoms of RV failure:
  
  • Exertional syncope
  • Oedema and ascites
  • Exertional angina, tachyarrhythmias (atrial flutter esp)
  • Raised JVP - prominent “a” wave
  • Anorexia, abdo pain and swelling = hepatic congestion
• Signs of associated conditions e.g. connective tissue disease

Question 9

What can be heard on auscultation in pulmonary hypertension?

Answer 9

Right sided 3rd or 4th heart sound (gallop)

Parasternal (RV) heave

Splitting of second heart sound

Murmur of pulmonary regurgitation, systolic murmur of tricuspid regurgitation

Question 10

What investigations would you do for pulmonary hypertension?

Answer 10

Echo (1st line is TTE) - assess RV function + estimate pulmonary arterial pressures

Right heart catheterisation (RHC) - confirms diagnosis by directly measuring PP

CT chest - check for lung pathology cause

PFT - as above

Other:

Bloods:

• BNP - RV/LV stretch
• LFTs - ?portal hypertension
• TFTs
• AI screen - anti-nuclear antibody

Imaging:

• CXR - lung disease
• ECG - shows right ventricular hypertrophy, strain patters or is normal
• Polysomnography - exclude sleep apnoea
• Isotope perfusion lung scanning - looks for thromboembolism
• MRI - assess cardiac structure, function, prognosis

Question 11

What changes are seen in pulmonary hypertension on ECG (e.g. after PE)?

Answer 11

1. Right axis deviation (QRSmore negative than positive in lead I);
2. Positive QRS complexes (‘dominant R waves’) in v1 and v2 suggesting right ventricular hypertrophy;
3. ST depression and t-wave inversion in the right precordial leads (v1-3) suggesting right ventricular strain;
4. Peaked p waves (p pulmonale) suggesting right atrial hypertrophy.

Question 12

Name 2 complications of pulmonary hypertension.

Answer 12

• Pulomonary regurgitation
• Tricuspid regurgitation

Question 13

What is the mean PAP in healthy individuals?

Answer 13

8-20mmHg

Question 14

What is the management of PAH(class I)?

Answer 14

Refer to specialised pulmonary hypertension centre

Directed at the PAH rather than the underlying cause

• Prostacyclin pathway agonists e.g. epoprostenol, treprostinil, iloprost
• Endothelin receptor antagonists e.g. ambrisentan, bosentan, macitentan
• NO-cGMP enhancers e.g. phosphodiesterase 5 inhibitors like sidenafil and tadalafil
• CCBs e.g. diltiazem or nifedipine

Refractory patients:

• Lung transplantation
• Creation of right to left shunt (temporary measure only)

Question 15

What is the management of class 3 PH?

Answer 15

Treat the underlying lung disease NOT the PAH

• Conventional (eg, vaccination, counselled against smoking, exercise)
• Supportive therapies (when indicated; eg, oxygen, diuretics).

Progression/refractory:

• Lung transplantation

Question 16

What is the management of class 2 (LHF) PH?

Answer 16

Treat the underlying left heart disease, NOT the PH

• Medical therapy
• Decongestion with diuretics
• Cardiac resynchronisation therapy
• Surgical or transcatheter interventions e.g. for CAD or valvular disease

Refractory/progressive:

• Left ventricular assist device
• Cardiac transplantation