Makindo Medical Notes

Related Subjects: |Assessing Breathlessness |Pulmonary Hypertension |Assessing Breathlessness |Pulmonary hypertension - Cor pulmonale

Shunts will always try to shift blood to a low pressure pulmonary circulation but this will cause pulmonary hypertension. See individual topics for more information

About

• Pulmonary Hypertension defined as increased pulmonary artery pressure
• Mean pulmonary artery pressure > 25 mmHg at rest and 30 mmHg at exercise.
• This leads then to RV Hypertrophy and right heart failure.
• It can be separated into Primary in which no underlying cause is found and secondary.

Physiology

• Pulmonary system is a very low resistance circuit about 1/8th that of systemic resistance

Causes

• Primary
  • A rare disease of children and young adults. Women > Men 2:1
  • Mean age at onset in the fourth to sixth decade
  • Less than 1% of all causes. No cause is found.
• Secondary
  • Commonest cause is secondary to left heart failure
  • Lung disease: COPD, Pulmonary fibrosis, Interstitial lung disease
  • Chronic thromboembolic pulmonary hypertension
  • Left to right shunts and Eisenmenger's: ASD, VSD
  • Drugs e.g. amphetamines, methamphetamines, and l-tryptophan
  • Connective tissue diseases e.g. scleroderma
  • HIV infection

Clinical

• Dyspnoea, fatigue, progressive pedal oedema.
• Right sided heart failure - hepatomegaly
• Cyanosis, Dizziness or fainting
• Chest pain or pressure, Palpitations

Investigations

• FBC, U&E, Elevated BNP
• ECG: right axis deviation, RV enlargement and strain, AF
• CXR: enlarged proximal pulmonary arteries with peripheral tapering or pruning of the pulmonary vasculature
• Echocardiogram: RV enlargement and structural issues
• Right heart catheterization: A procedure that directly measures the pressure in the heart and lungs.

Types of Pulmonary Hypertension: Categories

• Group 1: Pulmonary arterial hypertension (PAH), which is caused by narrowing of the pulmonary arteries.
• Group 2: Pulmonary hypertension due to left-sided heart disease.
• Group 3: Pulmonary hypertension due to lung diseases or low oxygen levels.
• Group 4: Pulmonary hypertension caused by chronic blood clots.
• Group 5: Pulmonary hypertension with unclear or multifactorial causes.

Management

• Medications: Low sodium diet and Diuretics e.g. Furosemide.
• Vasodilators
  • calcium channel blockers, Nifedipine, Amlodipine, Diltiazem
  • Epoprostenol infusion, Subcutaneous treprostinil
  • Bosentan (initiated orally at 62.5 mg twice daily and titrated up to 125 mg twice daily after 1 month)
  • Various others exists
• Chronic thromboembolism: Anticoagulants to prevent blood clots. Patients may respond to a pulmonary endarterectomy or balloon angioplasty which can be potentially curative
• Oxygen therapy: especially for patients with chronic lung diseases.
• Lifestyle changes: Quitting smoking, maintaining a healthy diet, and engaging in moderate physical activity can improve quality of life.
• Surgery: In severe cases, lung or heart-lung transplantation may be considered.

Patients with pulmonary arterial hypertension related to the scleroderma spectrum of diseases tend to have a poorer prognosis than that of those with idiopathic pulmonary arterial hypertension, whereas patients with pulmonary arterial hypertension related to congenital heart disease tend to have a better prognosis, perhaps because they have better right ventricular function