20th February 2025

A 72-year-old man is referred to respiratory clinic with a 6-month history of dry cough, exertional dyspnoea and fatigue.

A 72-year-old man is referred to respiratory clinic with a 6-month history of dry cough, exertional dyspnoea and fatigue. His past medical history includes glaucoma, diabetes and hypertension. Apart from his eye drops, his medication includes amlodipine, ramipril, metformin and gliclazide.

On examination, you note dyspnoea on exertion, minimal peripheral oedema and fine bibasal crackles on auscultation of the chest.

Blood tests organised by the GP are unremarkable. CXR shows bibasal interstitial shadowing. Echocardiogram reveals some mild hypertrophy of the left ventricle with an ejection fraction of 50% and a significantly hypertrophied right ventricle. Pulmonary artery pressure is 35 mmHg.

What is the most appropriate next step in the investigation?

Select the SINGLE most appropriate option from the list below. Select ONE option only.x