TABLE 2.

Potential role for initial monotherapy in specific pulmonary arterial hypertension (PAH) subsets

IPAH, HPAH and drug-induced PAH patient responders to acute vasoreactivity tests and with WHO FC I/II and sustained haemodynamic improvement (same or better than achieved in the acute test) after at least 1 year on CCBs only

Long-term-treated historical PAH patients with monotherapy (>5–10 years) stable with low-risk profile

IPAH patients >75 years old with multiple risk factors for heart failure with preserved LVEF (high blood pressure, diabetes mellitus, coronary artery disease, atrial fibrillation, obesity)

PAH patients with suspicion or high probability of pulmonary veno-occlusive disease or pulmonary capillary haemangiomatosis

Patients with PAH associated with HIV infection or portal hypertension or uncorrected congenital heart disease, as they were not included in RCTs of initial combination therapy

PAH patients with very mild disease (e.g. WHO FC I, PVR 3–4 WU, mPAP <30 mmHg, normal right ventricle at echocardiography)

Combination therapy unavailable or contraindicated (e.g. severe liver disease)

IPAH: idiopathic PAH; HPAH: heritable PAH; CCB: calcium channel blocker; PAP: pulmonary arterial pressure; PVR: pulmonary vascular resistance; LVEF: left ventricular ejection fraction; RCT: randomised controlled trial; WHO: World Health Organization; FC: Functional Class; WU: Wood Units; mPAP: mean PAP.