Acute vasoreactivity testing predicts outcome of idiopathic pulmonary arterial hypertension patients with a negative acute response

BACKGROUND: Acute vasoreactivity testing (AVT) during right heart catheterization (RHC) is performed in certain subsets of patients with pulmonary arterial hypertension (PAH) in order to identify those who benefit from calcium channel blockers. The present study aimed to investigate the prognostic value of pre-AVT, post-AVT, and changes in AVT (ΔAVT) parameters for idiopathic PAH (IPAH) patients with a negative acute response, and to identify sex differences that could be of prognostic value. METHODS: A total of 487 incident IPAH patients (171 males and 316 females) with a negative acute response to AVT were recruited from Shanghai Pulmonary Hospital between 2009 and 2018. Outcomes were predicted using the Kaplan-Meier curve and univariate/multivariate Cox regression analyses. All patients were followed up till January 2020, with outcome specified as all-cause mortality. RESULTS: Inhalation of iloprost aerosol improved the hemodynamic parameters for all patients. Post-PVR was decreased, and post-cardiac output (post-CO) and post-cardiac index (post-CI) were increased compared with pre-AVT parameters among males. Increased post- artery oxygen saturation (post-SaO(2)) and decreased post-mean right atrium pressure (post-mRAP) were also observed in females. For all patients, pre-CO ≥3.25 L/min, post-mPAP <53 mmHg, and post-mixed venous oxygen saturation (post-SvO(2)) ≤63% were parameters suggesting better prognosis. For males, patients with pre-PVR <12.47 Wood units, pre-SvO(2) ≥64%, and post-mean pulmonary artery pressure (post-mPAP) <51 mmHg had a better prognosis. For females, patients with ΔmPAP ≥−4 mmHg and ΔPVR ≥−0.25 Wood units had better outcomes. CONCLUSIONS: AVT parameters, including pre-AVT, post-AVT and ΔAVT, have a more important prognostic value than currently used for identify a small subgroup of patients with PAH who are suitable for high-dose calcium channel blockers. Sex differences in AVT parameters suggest that sex should be taken into account in estimating prognosis.