IS THERE VALUE IN REPEATING INHALED NITRIC OXIDE VASOREACTIVITY TESTS IN PATIENTS WITH PULMONARY ARTERIAL HYPERTENSION

Abstract

METHODS: We conducted a retrospective chart review of 54 individuals with PAH who underwent 2 RHC with NO challenges at the Cleveland Clinic between July 2013 and November 2018. Nitric oxide challenge was done at a dose of 40 ppm for 5 minutes. Full hemodynamic determinations were obtained before and during the inhalation of NO. Based on the difference in mean pulmonary arterial pressure (mPAP), patients were allocated to two groups: those who demonstrated increased vasoreactivity (drop in mPAP of $1 mmHg at second challenge compared to first) and those who demonstrated equal/decreased reactivity by the time of second RHC. We recorded demographic, functional, echocardiographic and survival data on all patients. RESULTS:We included 54 patients, age was 50.6 17.3 years old and 44 (82%) were female. The median time between the 2 NO challenges was 24.5 months (IQR 14.8-42 months). Hemodynamic determinations were similar between the 2 RHC’s, except for a higher right atrial pressure and pulmonary artery wedge pressure on the second RHC. The response to inhaled NO as assessed by absolute or percentage change in mPAP or PVR appeared to be less pronounced during the second than the first RHC; however the only significant comparison was of the percentage drop in mPAP (p1⁄40.02). Interestingly, patients who had an increase in vasoreactivity during the second RHC were more likely to receive treatment with PDE5 inhibitors at the time of first RHC. Similarly, the number of PAH-specific medications during the second RHC was higher in subjects who had an increase in the vasoreactivity during the second RHC (p1⁄40.03). Using Cox survival analysis, the change in mPAP or PVR (absolute or percentage drop) during NO at or between the first and second RHC had not impact on the overall survival when adjusted for age, gender, type of PAH and time between RHC. CONCLUSIONS: Pulmonary vascular reactivity to inhaled NO does not appear to significantly change over time; however there is great variability among patients. The number of PAH-specific treatment during the second RHC and the use of PDE5 inhibitors at first RHC was associated with an improvement in pulmonary vasoreactivity. CLINICAL IMPLICATIONS: Pulmonary vasoreactivity testing is done to identify possible medication management in patients in PAH. Little is known if pulmonary vasculature changes over time after initiation of PAH-specific therapy and whether this variation carries prognostic implications. DISCLOSURES: No relevant relationships by Allaa Almoushref, source1⁄4Web Response No relevant relationships by Adriano Tonelli, source1⁄4Web Response No relevant relationships by Rubabin Tooba, source1⁄4Web Response DOI: https://doi.org/10.1016/j.chest.2019.08.375 Copyright a 2019 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved. hestjournal.org 329A