[Acute response of right ventricular function to iloprost inhalations in patients with pulmonary arterial hypertension: preliminary evaluation with cardiac magnetic resonance imaging]

Abstract

Background: Pulmonary arterial hypertension (PAH) is a progressive disorder characterized by abnormally elevated blood pressure of the pulmonary circulation. Without treatment, PAH progresses rapidly to right ventricular (RV) failure and even death. Cardiac magnetic resonance imaging (CMRI) has been an accurate and reproducible tool to assessment of RV morphology and function, which are important factors in the prognosis of patients with PAH. The aim of this study is to investigate acute RV response to inhalation of aerosolized iloprost in patients with PAH using CMRI.

Methods: From March 2012 to March 2014, 48 patients with PAH underwent CMRI before and immediately after inhalation of iloprost with a single dose of 20 μg over 15 min-20 min. RV function parameters derived from CMRI images were analyzed before and after iloprost inhalation, including end-diastolic volume (EDV), end-diastolic area (EDA), end-systolic volume (ESV), end-systolic area (ESA), stroke volume (SV), ejection fraction (EF) and cardiac output (CO). Percentage of RV area change was also calculated [%RVAC=(EDA-ESA)/EDA×100%]. Wilcoxon's Sign Rank Test or Paired Samples t-Test was used to compare the differences of RV function parameters before and after inhalation.

Results: After iloprost inhalation, all patients showed significant decrease in RV EDV and RV ESV (P=0.007, P<0.001 respectively). Whereas, there were significant increase in RV SV (P=0.014), RV EF (P=0.009) and %RVAC (P=0.006). RV CO had no significant difference before and after inhalation (P=0.851).

Conclusions: Inhalation of iloprost can immediately improve RV function in patients with PAH, and noninvasive evaluation of the acute response with CMRI is feasibility.

1

FIESTA心脏短轴位测量RV容积。A：收缩末期；B：舒张末期。图示描记RV心内膜轮廓。 Measurement of RV volume with short axis images of FIESTA. The endocardial borders of RV at end-systole phase (A) and end-diastole phase (B) were manually traced (the white arc line). FIESTA: fast imaging employing steady-state acquisition; RV: right ventricle.

2

混合型结缔组织病并PAH，女，30岁，吸入伊洛前列素前、后FIESTA心脏短轴位图像比较。A、B分别为吸入伊洛前列素前、后心室中部收缩末期图像，C、D分别为吸入伊洛前列素前、后心室中部舒张末期图像。吸药后室间隔曲度较前好转，RV容积较前缩小，以收缩末期明显。 FIESTA short axis images before and after iloprost inhalation in a 30-year-old female PAH patient with mixed connective tissue disease. A, B show the mid-ventricular short-axis images at end-systole phase before and immediately after iloprost inhalation respectively; C, D are the corresponding images at end-diastole phase. After inhalation of iloprost, ventricular septal shifted toward the RV and there was significant reduction in RV volume, especially at end-systole phase.