pulmonary htn Flashcards
what are the 2 types of pulmonary htn
Pulmonary hypertension is of two types:
pulmonary artery hypertension:
- this results from disorders of the lung or arterial vasculature
pulmonary venous hypertension:
- this results from disorders of the pulmonary venous drainage or of the left heart
classification of pulm htn
Group 1 Pulmonary arterial hypertension (PAH)
- idiopathic PAH
- PAH associated with connective tissue disease: predominantly seen with scleroderma
Group 2 Left heart disease
- PH associated with left heart dysfunction, systolic, diastolic or valve disease
Group 3 Lung disease
- PH in patients with COPD or interstitial lung disease
Group 4 Chronic thromboembolic pulmonary hypertension
Group 5 Unclear and multifactorial mechanisms
- Rare diseases
Groups 2 and 3 contain the majority of patients,
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Classification:
- primary
- secondary:
- increased flow through the pulmonary artery
- resistance to pulmonary arterial flow
- pulmonary venous hypertension
primary pulmonary hypertension- define, WHO classification, features, ix. mx
The classification of pulmonary hypertension is currently changing with the term idiopathic pulmonary arterial hypertension (IPAH) becoming more widely used
Primary pulmonary hypertension (PPH, now IPAH)
- pulmonary arterial pressure > 25 mmHg at rest, > 30mmHg with exercise
- PPH is diagnosed when no underlying cause can be found
- around 10% of cases are familial: autosomal dominant
- endothelin thought to play a key role in pathogenesis
- associated with HIV, cocaine and anorexigens (e.g. fenfluramine)
World Health Organization classification functional status in primary pulmonary hypertension
- class I - no limitation on physical activity functional
- class II - slight limitation functional class
- III - pronounced limitation functional
- class IV - inability to carry out any physical activity without symptoms
Features
- more common in females, typically presents at 20-40 years old
- progressive SOB
- cyanosis
- right ventricular heave, loud P2, raised JVP with prominent ‘a’ waves, tricuspid regurgitation
Investigation
- echocardiography
Management
- diuretics if right heart failure
- anticoagulation
- vasodilator therapy: calcium channel blocker, IV prostaglandins, bosentan: endothelin-1 receptor antagonist
- heart-lung transplant
causes of increased flow in pulmonary artery
Causes include:
- systemic causes, e.g. anaemia, thyrotoxicosis
- left-to-right cardiac shunts that cause an increase in pulmonary arterial blood flow
- atrial septal defect
- atrioventricular defect
- ventricular septal defect
- patent ductus arteriosus
causes of resistance to pulmonary flow
resistance to the pulmonary arterial flow
- occlusion of pulmonary arteries, for example emboli, e.g. clot, fat, mycotic, tumour or air - the most common cause
- blockage of pulmonary arteries by vasculitis, e.g. polyarteritis nodosa
- chronic obstructive airways disease - emphysema, chronic bronchitis
- schistosomiasis
- bronchiectasis
- chronic asthma
- pulmonary fibrosis
- kyphoscoliosis
causes of pulmonary venous htn
The basic problem is that pulmonary venous return is “blocked” resulting in increased pulmonary venous pressure. The cause may arise at any point from the pulmonary veins to the systemic circulation.
Causes include:
- anomalous venous drainage - total or partial
- squeezing of the pulmonary veins by the pericardium acting as a purse-string - for example in constrictive pericarditis
- obstruction at the level of the left atrium:
- mitral stenosis or regurgitation
- atrial myxoma
- cor triatriatum
- left ventricular failure
- aortic stenosis or regurgitation
- co-arctation of the aorta
ix
ecg
- p pulmonale
RVH
- RAD
echo
- valve disease
R heart catheterisation: gold standard
- = help get mean pulm artery pressure
mx of pulm htn
diuretics control oedema from right heart failure
home oxygen to correct hypoxia
anticoagulation is recommended in pulmonary arterial hypertension (PAH) and is essential for patients with chronic thromboembolic pulmnary hypertension (CTEPH)
- primary (idiopathic) pulmonary hypertension is treated with anticoagulants (because it is virtually impossible to rule out persistent micro-emboli as the cause)
in patients with group 1 pulmonary arterial hypertension (idiopathic PAH, PAH associated with connective tissue disease - predominantly seen with scleroderma) (1,2)
- specific drugs have been found to be beneficial
- there are three main drug classes:
- prostanoids delivered iv, by nebuliser or subcutaneous (eg epoprostenol, iloprost, treprostinil),
- endothelin receptor antagonists (eg bosentan, ambrisentan), and
- phosphodiesterase inhibitors (eg sildenafil, tadalafil)
- these drugs are only prescribed through the designated centres
- side effects include flushing, headaches, gastro-intestinal disturbance and hypotension
- endothelin receptor antagonists require monthly liver function monitoring
CTEPH
treatment of choice for patients with CTEPH is pulmonary endarterectomy surgery > 90% 5 year survival
lifelong anticoagulation is also recommended.
In selected patients who have class 4 symptoms despite optimal medical therapy, bilateral lung or heart lung transplantation may be considered. The 5 year survival following transplantation is approximately 50-60%.
