P2597Riociguat as a bridge therapy for balloon pulmonary angioplasty in patients with severe chronic thromboembolic pulmonary hypertension

Abstract

Background: Balloon pulmonary angioplasty (BPA) has been reported as an effective treatment for the patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). However, there are still concerns about the procedural complications of BPA particularly in severe CTEPH patients. Riociguat directly stimulates soluble guanylate cyclase (sGC) independently of nitric oxide (NO) and increases the sensitivity of sGC of NO. Purpose: The purpose of present study was to evaluate the benefits of Riociguat pre-medical treatment before BPA in severe CTEPH patients. Methods: This study included 27 consecutive patients with inoperable, severe CTEPH, who had undergone BPA as the first session between January 2013 and August 2016. We defined severe CTEPH patients as WHO-FC III or IV and mean pulmonary arterial pressure (mPAP) of more than 30mmHg. Nineteen patients received Riociguat (6.5±1.5mg) before BPA (Riociguat Group), and the remaining eight patients did not any medications (No Pre-Med Group). We assumed the endpoint of BPA when the mPAP was achieved to be less than 25mmHg, or the further BPA was judged to be difficult. We compared the change of hemodynamic parameters and the plasma brain natriuretic peptide (BNP) levels, the numbers of BPA session, the complications associated with BPA, and the total amount of the contrast agent and radiation exposure in both groups. Results: The plasma BNP levels (Riociguat Group: from 188.5±204.8 to 71.4±69.2 pg/ml, p<0.01 vs No Pre-Med Group: from 146.9±164.1 to 141.9±147.8 pg/ml, p=0.8) and mPAP (Riociguat Group: from 43.1±4.2 to 34.5±5.5 mmHg, p<0.001 vs No Pre-Med Group: from 41.1±4.0 to 43.1±9.8 mmHg, p=0.5) was significantly improved in Riociguat Groups before BPA 1st session but not in No Pre-Med Group. There were no adverse effects associated with Riociguat. At the endpoint of BPA, the plasma BNP levels (Riociguat Group: from 188.5±204.8 to 33.9±32.7 pg/ml, p<0.01 vs No Pre-Med Group: from 146.9±164.1 to 24.1±7.4 pg/ml, p=0.07) and mPAP (Riociguat Group: from 43.1±4.2 to 21.5±2.0 mmHg, p<0.001 vs No Pre-Med Group: from 41.1±4.0 to 22.9±2.4 mmHg, p<0.001) was improved in both groups. The plasma BNP levels and mPAP at the baseline and endpoint between were no significant differences in both groups. The rate of severe complications associated with BPA was not significantly different in both groups (5.9% in Riociguat Group vs 11.1% in No Pre-Med Group). Importantly, the total numbers of BPA session and the total amount of contrast agent by which the mPAP was achieved to be less than 25 mmHg were significantly less in Riociguat Group than No Pre-Med Group (Riociguat Group vs No Pre-Med Group: total numbers of BPA session; 2.7±1.2 vs 4.5±1.8, p<0.01, total amount of contrast agent; 570±263 ml vs 871±348 ml, p<0.05). Conclusions: These findings indicate that Riociguat pre-medical treatment could serve as a bride therapy to effectively perform BPA procedure in patients with inoperable severe CTEPH.