The impact of ambrisentan and tadalafil upfront combination therapy on cardiac function in scleroderma associated pulmonary arterial hypertension patients: cardiac magnetic resonance feature tracking study.

The aim of this study was to evaluate the effect of upfront combination therapy with ambrisentan and tadalafil on left ventricular (LV) and right ventricular (RV) function in patients with systemic sclerosis-associated pulmonary arterial hypertension (SSc-PAH). LV and RV peak longitudinal and circumferential strain and strain rate (SR), which consisted of peak systolic SR (SRs), peak early diastolic SR (SRe), and peak atrial-diastolic SR (SRa) were analyzed using cardiac magnetic resonance imaging (CMRI) data from the recently published ATPAHSS-O trial (ambrisentan and tadalafil upfront combination therapy in SSc-PAH). Twenty-one patients completed the study protocol. Measures of RV systolic function (RV free wall [RVFW] peak longitudinal strain [pLS], RVFW peak longitudinal SRs [pLSRs]) and RV diastolic function (RVFW peak longitudinal SRa [pLSRa], RVFW peak circumferential SRe) were improved after treatment. LV systolic function (LV peak global longitudinal strain [pGLS]) and diastolic function (LV peak global longitudinal SRe [pGLSRe]) were also significantly improved at follow-up. Increased 6-min walk distance was significantly correlated with RVFW pLS and pLSRs, while the decrease in N-terminal pro-brain natriuretic peptide was correlated with LV pGLS. Increased cardiac index was associated with improved LV pGLSRe, and reduction in mean right atrial pressure was correlated with improved RVFW pLS and pLSRa. Combination therapy was associated with a significant improvement in both RV and LV function as assessed by CMR-derived strain and SR. Importantly, the improvement in RV and LV strain and SR correlated with improvements in known prognostic markers of PAH. (Approved by clinicaltrials.gov [NCT01042158] before patient recruitment.).

Ambrisentan and Tadalafil Up-front Combination Therapy in Scleroderma-associated Pulmonary Arterial Hypertension.

BACKGROUND: Scleroderma-associated pulmonary arterial hypertension (SSc-PAH) is a rare disease characterized by a very dismal response to therapy and poor survival. We assessed the effects of up-front combination PAH therapy in patients with SSc-PAH. METHODS: In this prospective, multicenter, open-label trial, 24 treatment-naive patients with SSc-PAH received ambrisentan 10 mg and tadalafil 40 mg daily for 36 weeks. Functional, hemodynamic, and imaging (cardiac magnetic resonance imaging and echocardiography) assessments at baseline and 36 weeks included changes in right ventricular (RV) mass and pulmonary vascular resistance as co-primary endpoints and stroke volume/pulmonary pulse pressure ratio, tricuspid annular plane systolic excursion, 6-minute walk distance, and N-terminal pro-brain natriuretic peptide as secondary endpoints. RESULTS: At 36 weeks, we found that treatment had resulted in significant reductions in median (interquartile range [IQR]) RV mass (28.0 g [IQR, 20.6-32.9] vs. 32.5 g [IQR, 23.2-41.4]; P < 0.05) and median pulmonary vascular resistance (3.1 Wood units [IQR, 2.0-5.7] vs. 6.9 Wood units [IQR, 4.0-12.9]; P < 0.0001) and in improvements in median stroke volume/pulmonary pulse pressure ratio (2.6 ml/mm Hg [IQR, 1.8-3.5] vs. 1.4 ml/mm Hg [IQR 8.9-2.4]; P < 0.0001) and mean ( ± SD) tricuspid annular plane systolic excursion (2.2 ± 0.12 cm vs. 1.65 ± 0.11 cm; P < 0.0001), 6-minute walk distance (395 ± 99 m vs. 343 ± 131 m; P = 0.001), and serum N-terminal pro-brain natriuretic peptide (647 ± 1,127 pg/ml vs. 1,578 ± 2,647 pg/ml; P < 0.05). CONCLUSIONS: Up-front combination therapy with ambrisentan and tadalafil significantly improved hemodynamics, RV structure and function, and functional status in treatment-naive patients with SSc-PAH and may represent a very effective therapy for this patient population. In addition, we identified novel hemodynamic and imaging biomarkers that could have potential value in future clinical trials. Clinical trial registered with www.clinicaltrials.gov (NCT01042158).