Pulmonary hypertension

Definition

• Elevation of the mean pulmonary arterial pressure (mPAP) ≥25 mmHg at rest
• Normal pressures are 15-30 mmHg in systole and 4-12 mmHg in diastole, resulting in normal mPAP <20 mmHg

Etiology

1. Pulmonary artery hypertension (PAH)
   • Idiopathic or hereditary
   • Drugs and toxins
     • Definitely appetite suppressants (e.g. aminorex, fenfluramine, dexfenfluramine, and diethylpropion), toxic rapeseed oil, and benfluorex
     • Possibly amphetamines, L-tryptophan, methamphetamines, cocaine, phenylpropanolamine, St. John's Wort, dasatinib, and interferon
   • Connective tissue disease
     • Systemic sclerosis
     • Rheumatoid arthritis and systemic lupus erythematosus
   • Infections
     • HIV
     • Schistosomiasis (most common cause worldwide)
   • Portal hypertension (portopulmonary hypertension)
   • Congenital heart disease, including Eisenmenger syndrome
2. Left heart disease, with an elevated left atrial (mean pressure >14 mmHg) and pulmonary venous pressure
   • Left ventricular systolic or diastolic dysfunction
   • Mitral and aortic valve disease
   • Also, restrictive cardiomyopathy, constrictive pericarditis, left atrial myxoma, congenital or acquired in- or outflow tract obstruction and congenital cardiomyopathies
3. Chronic lung disease or hypoxia
   • Chronic obstructive pulmonary disease (COPD)
   • Interstitial lung disease (ILD)
   • Combined pulmonary fibrosis and emphysema (CPFE)
   • Obstructive sleep apnoea (OSA)
4. Chronic thromboembolic pulmonary hypertension (CTEPH)
5. Miscellaneous
   • Chronic hemolytic anemia (e.g. sickle cell disease [SCD], beta-thalassemia, or spherocytosis)
   • Myeloproliferative disorders
   • Systemic disorders (e.g. sarcoidosis)
   • Metabolic disorders (e.g. glycogen storage disease)
   • Chronic kidney disease

Clinical Manifestations

Physical Examination

• Palpable P2 in MS has a LR+ 3.6 and LR– 0.05
• Loud P2 in cirrhosis has a LR+ 17.6 but only 38% sensitive
• Graham Steell murmur (high-pressure pulmonary regurgitation murmur) has LR+ 4.2
  • Diastolic murmur best hear at the LUSB
  • Similar to asortic regurgitation murmurs
• Can have fixed or wide splitting of the S2hiv renal

Investigations

• Imaging of the chest to assess parenchymal lung disease
• V/Q scanning to assess potential chronic thromboembolic disease
• Pulmonary function testing with DLCO
• Serologic studies for connective tissue disease, liver disease, and HIV
• Sleep study to rule out OSA