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Vasoreactivity Testing in PAH — EECC MCQ

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ModeratePulmonary Vascular DiseaseVasoreactivity Testing in PAHEECC

A 55-year-old woman with suspected PAH undergoes right heart catheterisation. The results show mPAP 42 mmHg, PAWP 12 mmHg, PVR 8 WU, and CO 3.5 L/min. Acute vasoreactivity testing with inhaled nitric oxide is performed. What defines a positive vasodilator response?

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Reveal the answer and explanation

Correct answer: E — A fall in mPAP ≥10 mmHg to an absolute value ≤40 mmHg, with unchanged or increased cardiac output

Acute vasoreactivity testing during RHC is performed in IPAH/hereditary PAH to identify the minority of patients (~10-15%) who may respond to high-dose calcium channel blocker therapy. The 2022 ESC/ERS PH Guidelines define a positive response as: (1) fall in mPAP ≥10 mmHg, AND (2) absolute mPAP ≤40 mmHg, AND (3) cardiac output unchanged or increased. Only patients meeting ALL three criteria are classified as 'responders' and can be trialled on CCBs (nifedipine, diltiazem, or amlodipine at high doses). Testing agents include inhaled nitric oxide (most commonly used), IV epoprostenol, or inhaled iloprost. Vasoreactivity testing is NOT recommended in non-IPAH forms of PH (e.g. CTD-PAH, Group 2-4 PH).

Reference: ESC/ERS (2022): Guidelines for Pulmonary Hypertension