PURPOSE: Patients with scleroderma associated pulmonary arterial hypertension (SSc-PAH) have a worse prognosis vs. idiopathic PAH (iPAH). We sought to determine the relative changes in clinical characteristics and right ventricular (RV) function in incident SSc-PAH vs. iPAH following 1 year of PH specific therapy.
METHODS: Following index PAH diagnosis (pre-therapy), patients were divided into two groups: SSc-PAH (n=9) and iPAH (n=17). Clinical, hemodynamic and Doppler-echo (DE) variables were analyzed. Emphasis was placed on DE measures of RV function; tricuspid annular plane systolic excursion (TAPSE), systolic eccentricity index (EIs) and the stroke volume surrogate, RV outflow tract velocity time integral (VTI). DE measures were repeated at 1 year from index diagnosis. *P<0.05, †P<0.01.
RESULTS: At baseline, SSc-PAH patients were older (62 ±7 vs 47±16 years*) , more symptomatic (NYHA class 3.2±0.6 vs 2.7±0.6*), with a lower 6MWD (226±122 vs 350±127*). SSc-PAH patients trended toward lower mPAP (46±10 vs. 52±9 mmHg; p=0.12), but similar cardiac index (2.4±0.6 vs. 2.3±0.5 l/min/m2). Despite a similar baseline PVR (9.4±5 vs. 10.9±5), 66% of SSc-PAH patients had a baseline TAPSE <2.0 cm, whereas in iPAH 66% of subjects had a TAPSE≥2.0 cm. These results suggest worse baseline RV adapation to afterload in SSc-PAH. At one year, SSc-PAH patients were on more aggressive therapy (prostacylin use 44% SSc-PAH vs. 24% iPAH). Nevertheless, there was less 6MWD improvement in SSc-PAH vs. iPAH (+63±84 vs. 96±113 meters*). At 1 year, repeat DE showed lesser improvements in EIs (-0.1±0.7 vs. -0.5±0.8†) and VTI (+4.1±3.5 vs. +5.6±2.9†) in SSC-PAH vs. iPAH. The mean TAPSE in SSc-PAH was only 1.9±0.3 cm, and 66% had a TAPSE<2.0 cm. In contrast, in iPAH the TAPSE was 2.1±0.4 cm, and 65% had a TAPSE≥2.0 cm.
CONCLUSIONS: These results suggest greater intrinsic RV dysfunction and less response to PH specific therapy in SSc-PAH vs. iPAH.
CLINICAL IMPLICATIONS: Patients with SSc-PAH may require much more aggressive PH specific therapy in order to achieve comparable improvements in RV function.
DISCLOSURE: The following authors have nothing to disclose: Justin Roberts, Anjali Fields, Paul Forfia
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