What question did this study set out to answer?

This study aims to evaluate the effects of switching from phosphodiesterase-5 inhibitors to riociguat on pulmonary haemodynamics and clinical outcomes in CTEPH patients post-BPA.

January 10, 2026BMC Pulmonary Medicine0 citationsOpen Access

Haemodynamic and clinical impacts of switching phosphodiesterase-5 inhibitors to riociguat in patients with chronic thromboembolic pulmonary hypertension (CTEPH) after balloon pulmonary angioplasty (BPA) – a prospective cohort study

TKTimothy Ho Him KamPrince of Wales Hospital KKKevin Ka Ho KamPrince of Wales Hospital MWMichael Ka Lam WongGrantham Hospital

Key Result

Switching from PDE5 inhibitors to riociguat in CTEPH patients after BPA significantly reduced PVR by 2.16 Wood units and mPAP by 4.79 mmHg at 26 weeks (p = 0.007).

Key Points

This study aims to evaluate the effects of switching from phosphodiesterase-5 inhibitors to riociguat on pulmonary haemodynamics and clinical outcomes in CTEPH patients post-BPA.
Enrolled symptomatic CTEPH patients after balloon pulmonary angioplasty
Conducted a 24-hour washout period of PDE5i prior to switching to riociguat
Assessed changes in pulmonary haemodynamics and functional outcomes at week 26
Significant reduction in pulmonary vascular resistance (PVR) by -2.16 Wood units
Mean pulmonary artery pressure (mPAP) decreased by -4.79 mmHg
Improvements observed in cardiac index, WHO functional class, 6-minute walking distance, and NT-proBNP levels
68.75% of patients experienced treatment-related adverse events
Clinical worsening occurred in four patients, including two unrelated deaths

Structured PICO

Does switching from sildenafil to riociguat improve pulmonary hemodynamics and functional outcomes in symptomatic CTEPH patients after balloon pulmonary angioplasty?

Population

16 patients with chronic thromboembolic pulmonary hypertension (CTEPH) who remained symptomatic (WHO functional class II or III) after completion of balloon pulmonary angioplasty (BPA), on a stable and maximally tolerated dose of sildenafil for at least 6 weeks. Mean age 62.3 ± 14.6 years, 75% female.

Intervention

Riociguat administered orally, initiated at 1 mg three times daily (TID) and titrated up to a maximum of 2.5 mg TID over an 8-week period, followed by an 18-week maintenance phase (total 26 weeks), after a 24-hour washout from sildenafil.

Outcome

Changes in pulmonary vascular resistance (PVR) and mean pulmonary artery pressure (mPAP) from baseline to week 26surrogate

Switching from sildenafil to riociguat in CTEPH patients who remain symptomatic after balloon pulmonary angioplasty significantly improves pulmonary hemodynamics and functional capacity, though it carries a considerable risk of adverse events like hypotension.

Main Result

Absolute Event Rate: 0% vs 0%

Abstract

Abstract Background For patients with chronic thromboembolic pulmonary hypertension (CTEPH), balloon pulmonary angioplasty (BPA) has been associated with superior reductions in mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) when compared to riociguat. In patients with pulmonary arterial hypertension (PAH), greater clinical improvements were observed after switching from phosphodiesterase-5 inhibitors (PDE5i) to riociguat. However, the impact of transitioning from PDE5i to riociguat on pulmonary haemodynamics and functional outcomes after BPA remains unclear. Methods This prospective, open-label, single-arm, study enrolled CTEPH patients who remained symptomatic following BPA. After a 24-hour PDE5i washout period, patients were switched to riociguat. At week 26, primary outcomes assessed changes in haemodynamics including PVR and mPAP. Secondary endpoints evaluated cardiac index; functional status including WHO functional class, 6-minute walking distance (6MWD), REVEAL Lite 2 score; biochemical markers such as N-terminal prohormone of brain natriuretic peptide (NT-proBNP); and echocardiographic measurements of right-heart function. Treatment-related adverse events and clinical worsening were monitored throughout the study. Results From July 2024 to January 2025, 16 patients (mean age 62.3 ± 14.6 years; 75% female) were recruited, with 14 completing the 26-week follow-up. At week 26, significant reductions occurred in PVR (-2.16 Wood units; CI -3.64 to -0.69; p = 0.007) and mPAP (-4.79 mmHg; Confidence Interval CI -8.05 to -1.52; p = 0.007). Significant improvements were also noted in cardiac index, WHO functional class, 6MWD, REVEAL Lite 2 score and NT-proBNP levels. Echocardiographic measurements of right-heart function did not demonstrate significant improvement. Treatment-related adverse events were observed in 11 patients (68.75%). Clinical worsening occurred in four patients, including two deaths unrelated to treatment and two unplanned hospitalisations due to pulmonary hypertension. Conclusion In CTEPH patients after completion of BPA, replacing PDE5i with riociguat significantly enhanced pulmonary haemodynamics and functional capacity but was accompanied by a considerable risk of treatment-related adverse events. Trial registration ClinicalTrials.gov Identifier NCT06715280 retrospectively registered on 26/11/2024.

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