Effect of imatinib as add-on therapy on echocardiographic measures of right ventricular function in patients with significant pulmonary arterial hypertension

Abstract

Aims: Imatinib mesylate, as add-on therapy in patients with pulmonary arterial hypertension (PAH) who remain inadequately treated despite receiving at least two PAH-specific drugs, improves exercise capacity and haemodynamics. We evaluated whether 24 weeks of add-on therapy with imatinib compared with placebo also improves right ventricular (RV) function assessed by echocardiography.

Methods and results: Echocardiograms were obtained at baseline, 12 weeks, and 24 weeks in 74 patients randomized to imatinib or placebo in the Imatinib in Pulmonary arterial hypertension, a Randomized Efficacy Study (IMPRES) trial. Right ventricular function was assessed by tissue Doppler tricuspid annular peak systolic velocity (TA S'), tricuspid annular plane systolic excursion (TAPSE), RV Tei index, and RV fractional area change. Between-treatment-group differences in the changes from baseline to week-24 were assessed using an ANCOVA with the last observation carried forward. At week-24 patients randomized to imatinib demonstrated greater improvements in TA S' (1.6 ± 2.3 imatinib vs. 0.5 ± 2.4 cm/s placebo, P = 0.007) and RV Tei index (-0.11 ± 0.18 imatinib vs. 0.05 ± 0.18 placebo, P = 0.005) compared with placebo, but not in TAPSE (0.07 ± 0.44 imatinib vs. 0.03 ± 0.32 cm placebo, P = 0.08). Imatinib therapy was also associated with significant reduction in peak tricuspid regurgitation velocity, increase in LV size, and improvement in LV early diastolic relaxation velocity.

Conclusions: Among patients with advanced PAH who remain symptomatic on at least two PAH-specific drugs, treatment with imatinib compared with placebo is associated with significant improvements in echocardiographic measures of RV function, in addition to LV size and LV early diastolic relaxation.

Clinical trial registration: NCT00902174 (Clinicaltrials.gov).

Keywords: Echocardiography; Pulmonary heart disease; Pulmonary hypertension; Trials.

Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

Figures

Figure 1

Disposition of patients in the IMPRES Echocardiographic sub-study.

Figure 2

TA S′ (A) and RV Tei index (B) at baseline, 12 weeks, and 24 weeks by treatment assignment (imatinib  vs. placebo). P-value is based on ANCOVA with last value carried forward.

Figure 3

Scatter plots demonstrating the change in invasively measured mPAP (A, D), CI (B, E), and PVR (C, F) by change in TA S′ (A–C in blue) and by change in RV Tei index (D–F in red) from baseline to 24 weeks. Spearman correlation coefficient and associated P-values are given for the relationship between the invasive parameter and echocardiographic measure as continuous variables.