Chronic thromboembolic pulmonary hypertension is a severe pulmonary vascular disease caused by residual organised thrombi and microvascular remodeling resulting in increased pulmonary vascular resistance and right heart failure. Pulmonary endarterectomy is the treatment of choice in patients with operable CTEPH. However, in approximately 40% of CTEPH cases, surgery is not deemed of benefit because of the location of the lesions (too distal to reach during surgery) or presence of comorbidities associated with post-surgical risk. For these patients, treatment with PAH medications, especially Riociguat, targeting microvascular disease or balloon pulmonary angioplasty is recommended. The RACE trial is a phase 3, multicentre, open-label, randomised control trial comparing safety and efficacy of BPA versus medical therapy, Riociguat, in newly diagnosed, treatment naïve patients with inoperable CTEPH (Lancet Resp Med 2022).  The main outcome of this study was that BPA had a superior effect on pulmonary vascular resistance reduction in comparison to medical therapy by Riociguat. In the current study (Circ Cardiovasc Interv 2025), the authors performed a post-hoc analyses in 100 patients of the RACE study with complete data on the primary endpoint, change in pulmonary vascular resistance (n=49 Riociguat; n=51 BPA), to test the hypothesis that Riociguat and BPA may exert different effects on RV afterload and RV function. In this study they extended the analyses of RV afterload by also investigating effects on pulsatile arterial load (PA compliance, CPA) and the integrated index of steady and pulsatile arterial load (effective arterial elastance ,Ea). In addition, the effect on RV function was determined by investigating changes in RV preload (mean right atrial pressure, mRAP), changes in RV contractile function (RV stroke work) and myocardial oxygen consumption (rate pressure product, RPP). As already demonstrated with the RACE trial, both Riociguat and BPA reduced pulmonary vascular resistance, albeit BPA treatment resulted in a more pronounced reduction in pulmonary vascular resistance. Similar effects were observed for the other indices of RV afterload (Ea and CPA). Treatment with BPA resulted in marked improvements of mRAP, RV stroke work and the rate pressure product, whereas treatment with Riociguat resulted only in a small decrease in rate pressure product and no effect was observed on mRAP or RV stroke work. The authors could confirm these results further in an ancillary 26 weeks follow-up study in which 54 symptomatic patients with residual pulmonary vascular resistance >4 WU after 26 weeks of treatment (n=18 add-on Riociguat after BPA; n=36 add-on BPA after Riociguat) were included. The authors explain these differences in effect of BPA and Riociguat based on the differences in mode of action of the intervention, in which Riociguat mainly targets the microvasculature, whereas BPA restores flow in the narrowed or obstructed vessels. This study ones again shows that a dramatic reduction in RV afterload is needed to induce any improvements in RV function. In addition, based on the observation that 73% of patients receiving Riociguat remained symptomatic after 26 weeks of treatment and needed add-on BPA intervention (in contrast to 35% in BPA group), demonstrates the superiority of BPA in patients with inoperable CTEPH. BPA resulted in a significant reduction in RV afterload and improvement of RV function. Nevertheless, it should not be concluded that BPA is a replacement for medical therapy in patients with inoperable CTEPH. It should rather be considered as a complementary treatment modality in which patients receive initial mono- or duo-therapy prior to the BPA procedure. This IMPACT-CTEPH is currently ongoing (NCT04780932) and will provide further evidence for such a multimodality approach in patients with inoperable CTEPH.