Makindo Medical Notes.com

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About

• Mean pulmonary artery pressure > 25 mmHg at rest and 30 mmHg at exercise.
• Primary Pulmonary hypertension suggests no cause can be found.
• Rare disease 2/million per annum

Aetiology

• Increased pulmonary vascular resistance
• Flow is the same in the pulmonary and systemic circulation assuming no shunts
• Total Pulmonary vascular cross-sectional area is much greater
• Vasoconstriction > Vasodilation. Fibrosis.

Associations

• Appetite suppressants - fenfluramine
• Vasculitis
• Connective tissue disease

Genetics

• There appears to be an autosomal dominant familial type with mutations in the type II bone morphogenetic protein receptor gene BMPR2 and Activin receptor-like kinase type 1

Classification

• Pulmonary arterial hypertension
• Pulmonary venous hypertension
• PH associated with respiratory disease/hypoxia
• PH related to thrombosis or embolic disease
• PH due to disease of pulmonary vasculature

Clinical

• Mainly affects women aged 20-30
• Progressive fatigue and breathlessness
• Loud P2 (Pulmonary valve closure)
• Right-sided S3 and RV heave
• Large 'a' and 'v' wave in JVP, TR
• PSM due to severe TR
• Pulmonary systolic flow murmur

Investigations

• FBC: polycythaemia. U&E
• ECG - RVH and RBBB and P pulmonale
• CXR - enlarged PA + pruning of peripheral vessels
• Echo - RV dilatation and TR. Pulmonary hypertension is based on the mean pulmonary artery pressure readings mean > 25 mmHg at rest and 30 mmHg at exercise
• CT-PA - may suggest a diagnosis of recurrent PE as a cause
• Pathology shows plexiform lesions and in situ thrombosis

Management

• Oxygen for hypoxia, Diuretics for oedema, Digoxin, Anticoagulation improves prognosis
• Some respond well to high dose Calcium channel blockers - only those with evidence of response should be continued on them such as Amlodipine 20-40 mg/day or Nifedipine 240 mg /day. Patients can be selected using a vasodilator test.
• Iloprost therapy (Prostacyclin) by infusion or nebulised to those with NYHA classification III or IV. There are a variety of different prostaglandin therapies available
• Endothelin (ET-A and ET-B) receptor antagonists Bosentan
• Sildenafil (viagra) has been used and has effects similar to nitric oxide
• Atrial septostomy may help but is really still under evaluation
• Single or double-lung transplant or Heart-lung transplantation
• Birth control as Pregnancy contraindicated
• Exercise limited, Avoid flying/hypoxia/altitude
• Venesection significant polycythaemia