A follow-up vasoreactivity test after treatment initiation may offer valuable prognostic information in patients with pulmonary arterial hypertension (PAH), according to a study published in the Journal of Cardiology. 

The definitive way to diagnose PAH is through invasive hemodynamic assessment via right heart catheterization. During this procedure, an acute vasoreactivity test is performed to identify patients who may respond well to high-dose calcium channel blockers. The preferred agent for vasoreactivity testing is inhaled nitric oxide. 

Studies indicate that PAH disease progression corresponds with a worsening pulmonary vascular response to inhaled nitric oxide. Nevertheless, the prognostic value of an acute vasoreactivity test using inhaled nitric oxide has not been fully elucidated. 

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The authors of the study hence sought to retrospectively analyze the prognostic value of follow-up vasoreactivity tests among 36 patients with PAH who had undergone treatment. The research team recruited patients who met the clinical definition of PAH (mean pulmonary arterial pressure ≥ 25 mmHg and pulmonary arterial wedge pressure ≤ 15 mmHg). The recruited patients must have been on some form of PAH therapy (calcium channel blockers, prostacyclin analogues, etc) for at least 2 weeks prior to referral. 

Read more about PAH etiology 

The research team measured hemodynamic parameters during right heart catheterization, while cardiac output was measured using the thermodilution method. Baseline readings were recorded. Follow-up readings after the initiation of treatment were decided at the discretion of the attending physician. 

The authors of the study reported 2 main findings: first, pulmonary vascular reactivity decreases over time; second, the remaining vascular dilatory reserve at follow-up after the initiation of treatment is useful in predicting subsequent all-cause mortality. 

“Follow-up acute vasoreactivity tests achieved after PAH-specific treatment could contribute to the detection of such high-risk subgroups who might have to be carefully monitored and referred for early lung transplantation,” the authors of the study wrote.


Ishii S, Hatano M, Maki H, et al. Prognostic value of follow-up vasoreactivity test in pulmonary arterial hypertensionJ Cardiol. 2023;S0914-5087(23)00005-9. doi:10.1016/j.jjcc.2023.01.005