THE BEST CARDIOLOGISTS IN YELAHANKA
Pulmonary hypertension is an uncommon but important cause of dyspnoea. Many patients with
this chronic and often severe illness will have raised pulmonary artery pressures as a result of a
cardiac or respiratory illness. Other patients may present with increasing dyspnoea without an
obvious cardiac or respiratory problem. Idiopathic (primary) pulmonary hypertension (IPH)
is diagnosed only when other causes of pulmonary hypertension have been excluded.
By definition, pulmonary hypertension is present when the mean pulmonary artery pressure
(PAP) exceeds 25 mmHg at rest or 30 mmHg during exercise. The classification of pulmonary
hypertension has been revised. The Venice classification was released in 2003. The term ‘primary pulmonary
hypertension’ has been replaced with ‘idiopathic pulmonary hypertension’
Patients may have used fenfluramine or phenermine (appetite-suppressing drugs), or both.
Use of these drugs for long periods has been associated with the greatest risk of developing
In cases of IPH there may be a family history (6%; autosomal dominant condition with
incomplete penetrance, 20–80%). The majority of familial cases are associates with a mutation
on the BMPR2 gene.
There may be associated symptoms including fatigue, chest pain, syncope and oedema.
Cough and haemoptysis can be present.
270 PRACTICAL CARDIOLOGY
The examination may help in assessing the severity of the patient’s dyspnoea as he or she
undresses. Try to work out the patient’s functional class from the history and examination
(p. 256) (NYHA I–IIII, often called the NYHA–WHO class when related to pulmonary hypertension).
There may be signs of chronic lung disease or congenital heart disease, or specific signs
of pulmonary hypertension and right heart failure (p. 257).
Investigations are directed at finding an underlying reason for pulmonary hypertension—
idiopathic pulmonary hypertension is a diagnosis of exclusion—and at assessing its severity
and potential reversibility.
The chest X-ray is abnormal in 90% of IPH patients. It may show pulmonary fibrosis or an
abnormal cardiac silhouette—RV dilatation. There may be large proximal pulmonary arteries
that appear ‘pruned’ in the periphery, and the heart may appear enlarged because of right
Respiratory function tests may show a normal, restrictive or obstructive pattern. Moderate
pulmonary hypertension itself is associated with a reduction in the diffusing capacity for the
carbon monoxide test (DLCO) to about 50% of predicted.
On the ECG look for signs of right heart strain or hypertrophy, which are present in up to
90% of patients
The blood gas measurements may show hypercapnia—elevated pCO2 in hypoventilation
syndromes—but hypocapnia is more common in IPH because of increased alveolar ventilation.
Mild hypoxia (reduction in pO2) may be present in IPH, and is more severe when pulmonary
hypertension is secondary to lung disease.
On CT pulmonary angiogram (CTPA), ventilation/perfusion (V/Q) lung scan or Doppler
venograms look for a deep venous thrombosis (DVT) and PE and assess the extent of involvement
of the pulmonary bed. A high-resolution CT scan of the lungs is the best way of looking
for interstitial lung disease.
The six-minute walking test predicts survival and correlates with the NYHA–WHO class.
Reduction in arterial oxygen concentration of more than 10% during this test predicts an almost
threefold mortality risk over 29 months. Patients unable to manage 332 m in six minutes also
have an adverse prognosis.