Impact of rapid sequential combination therapy on distinct haemodynamic measures in newly diagnosed pulmonary arterial hypertension.

Abstract

In pulmonary arterial hypertension (PAH), upfront combination therapy with ERA and PDE5i is associated with a reduction in morbidity and mortality events and improves standard haemodynamics, but data remain limited. Aims of this study were (i) to capture detailed haemodynamic effects of rapid sequential dual combination therapy in patients with newly diagnosed PAH; (ii) to monitor the impact of treatment initiation on clinical variables and patients' risk status, and (iii) to compare the treatment effect in patients with 'classical PAH' and 'PAH with co-morbidities'. Fifty patients (median age 57 [42-71] years, 66% female) with newly diagnosed PAH (76% idiopathic) were treated with a PD5i/sGC-S or ERA, followed by addition of the respective other drug class within 4weeks. All patients underwent repeat right heart catheterization (RHC) during early follow-up. At early repeat RHC (7±2months), there were substantial reductions in mean pulmonary artery pressure (mPAP: 52.2±13.5 to 39.0±10.6mmHg; -25.3%), and pulmonary vascular resistance (PVR: 12.1±5.7 to 5.8±3.1 WU; -52.1%), and an increase in cardiac index (2.1±0.4 to 2.7±0.7mL/min/m2; +32.2%) (all P<0.05). Haemodynamic improvements correlated with improved clinical parameters including 6-min walking distance (336±315 to 389±120m), NTproBNP levels (1.712±2.024 to 506±550ng/L, both P<0.05) and WHO-FC at 12months, resulting in improved risk status, and were found in patients with few (n=37) or multiple cardiovascular co-morbidities (BMI>30kg/m2, hypertension, diabetes, coronary artery disease [≥3]; n=13), albeit baseline PVR in PAH patients with multiple co-morbidities was lower (9.3±4.4 vs. 13.1±5.9 WU) and PVR reduction less pronounced compared with those with few co-morbidities (-42.7% vs. -54.7%). However, comprehensive haemodynamic assessment considering further variables of prognostic relevance such as stroke volume index and pulmonary artery compliance showed similar improvements among the two groups (SVI: +50.0% vs. +49.2%; PAC: 91.7% vs. 100.0%). Finally, the 4-strata risk assessment approach was better able to capture treatment response as compared with other approaches, particularly in patients with co-morbidities. Rapid sequential combination therapy with PDE5i/sGC-S and ERA substantially ameliorates cardiopulmonary haemodynamics at early follow-up in patients without, and to a lesser extent, with cardiovascular co-morbidities. This occurs in line with improvements of clinical parameters and risk status.