Kazui, Sho

BACKGROUND: The right ventricular (RV) response to pressure overload is a crucial determinant of outcomes in pulmonary arterial (PA) hypertension. Sotatercept improves clinical outcomes, but its effects on the right ventricle have been inconsistent. We evaluated the effects of sotatercept on load-independent measures of RV contractility, RV–PA coupling, and right heart deformation at rest and exertion in patients with PA hypertension. METHODS: In this prospective trial among participants with PA hypertension recruited between July 2024 and May 2025, we performed simultaneous echocardiography and invasive pressure measurements during rest and exercise to evaluate changes in RV contractility (end-systolic elastance [Ees]), afterload (PA elastance [Ea]), RV–PA coupling (ratio of arterial Ea to Ees), and right heart deformation, including RV and right atrial strain, before and after 24 weeks of sotatercept using mixed models. RESULTS: Among 30 participants (n=21; 70% female; mean age, 49.3 years [SD 13.5]), sotatercept decreased PA Ea. These changes were associated with reduced RV contractility, PA pulsatility index, and the maximal rate of RV pressure increase over time (dP/dt max ; P <0.001 for all). The decrease in Ees was associated with a decrease in PA Ea (r=+0.70 [95% CI, +0.44 to +0.85]; P <0.0001) with preserved RV–PA coupling (mean difference, +0.08 [95% CI, −0.11 to +0.26]; P =0.42). Although systolic indices measured at the base of the right ventricle (tricuspid annular plane systolic excursion and systolic velocity of the lateral tricuspid annulus) decreased after sotatercept use, there was an increase in RV free wall–dependent systolic indices, including resting and exercise RV free wall strain (mean difference, +6.2% [95% CI, +4.5 to +7.8]; P <0.0001) and fractional area change ( P =0.0001). Beyond the right ventricle, there was also improved right atrial filling and contractile performance across rest and exercise ( P <0.0001 for all). CONCLUSIONS: Sotatercept decreases RV contractility in proportion to reduced afterload, while preserving the RV–PA coupling relationship. Despite decreased RV contractility, global measures of right heart performance, such as RV free wall strain and RA strain, improve, alongside redistribution of RV deformation from annular motion to free wall shortening. These data suggest that sotatercept causes an energetically favorable reduction in resting RV contractility to match the lower afterload, which does not appear physiologically detrimental when considering the concurrent improvement in RV free wall contractile mechanics and exertional right heart reserve. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT06409026.

Abstract Background and Aims Exercise stress echocardiography is recommended as an alternative to invasive testing for diagnosing heart failure with preserved ejection fraction (HFpEF), but an evidence-based operational framework guiding its application is lacking. Methods Patients with chronic unexplained dyspnoea underwent invasive haemodynamic exercise testing with simultaneous echocardiography to test the hypotheses that (i) the current diagnostic algorithms (H2FPEF, HFA-PEFF, and HFpEF-ABA scores) could be enhanced when combined with exercise echocardiography; and (ii) incorporating resting left atrial (LA) compliance (LA reservoir strain divided by E/e′) could further improve diagnostic triage, using separate cut points optimizing sensitivity and specificity. Findings were then validated in an international multicentre cohort. Results Of 482 patients, HFpEF was present in 386 and non-cardiac dyspnoea in 96. Sensitivity to detect HFpEF was only 55%–60% and accuracy 61%–67% using individual diagnostic scores with currently recommended exercise echocardiography. Addition of abnormal resting LA compliance to exercise echocardiography increased sensitivity to 84%–85% but increased the false-positive rate to 31%–43%. Applying separate cut points that optimize specificity and sensitivity (either exercise E/e′ ≥ 13.8 or resting LA compliance ≤1.6% to rule-in HFpEF; both exercise E/e′ &lt; 7.2 and resting LA compliance &gt;4.4% to rule-out HFpEF, remaining patients indeterminate who require invasive testing) improved sensitivity to 95%–99% among definitively classified patients and reduced the number of patients that require invasive exercise testing from ∼60% to ∼30%. Findings were replicated in a multicentre, international validation cohort of patients undergoing rest–exercise echocardiography and invasive exercise testing. Conclusions Currently used non-invasive approaches to HFpEF diagnosis have inadequate sensitivity, indicating that exercise echocardiography cannot supplant invasive testing. Addition of LA strain imaging with optimized rule-in or rule-out values improves diagnostic triage by expanding non-invasive rule-in/rule-out classifications while identifying patients who still require invasive testing in the evaluation of HFpEF.