Open AccessEffects of Acute Intravenous Iloprost on Right Ventricular Hemodynamics in Rats with Chronic Pulmonary Hypertension
Author(s) -
Zeineh Nabil S.,
Bachman Timothy N.,
ElHaddad Hazim,
Champion Hunter C.
Publication year - 2014
Publication title -
pulmonary circulation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.791
H-Index - 40
ISSN - 2045-8940
DOI - 10.1086/677358
Subject(s) - medicine , iloprost , contractility , cardiology , ventricle , pulmonary artery , ejection fraction , hemodynamics , pulmonary hypertension , inotrope , anesthesia , heart failure , prostacyclin
The inotropic effects of prostacyclins in chronic pulmonary arterial hypertension (PAH) are unclear and may be important in directing patient management in the acute setting. We sought to study the effects of an acute intravenous (IV) infusion of iloprost on right ventricular (RV) contractility in a rat model of chronic PAH. Rats were treated with monocrotaline, 60 mg/kg intraperitoneally, to induce PAH. Six weeks later, baseline hemodynamic assessment was performed with pressure‐volume and Doppler flow measurements. In one group of animals, measurements were repeated 10–15 minutes after IV infusion of a fixed dose of iloprost (20 μg/kg). A separate group of rats underwent dose‐response assessment. RV contractility and RV–pulmonary artery coupling were assessed by the end‐systolic pressure‐volume relationship (ESPVR) and end‐systolic elastance/effective arterial elastance (Ees/Ea). RV cardiomyocytes were isolated, and intracellular cAMP (cyclic adenosine monophosphate) concentration was measured with a cAMP‐specific enzyme immunoassay kit. Animals had evidence of PAH and RV hypertrophy. Right ventricle/(left ventricle + septum) weight was 0.40 ± 0.03. RV systolic pressure (RVSP) was 39.83 ± 1.62 mmHg. Administration of iloprost demonstrated an increase in the slope of the ESPVR from 0.29 ± 0.02 to 0.42 ± 0.05 ( P <. 05). Ees/Ea increased from 0.63 ± 0.07 to 0.82 ± 0.06 ( P <. 05). The RV contractility index (max d P /d t normalized for instantaneous pressure) increased from 94.11 to 114.5/s ( P <. 05), as did the RV ejection fraction, from 48.0% to 52.5% ( P <. 05). This study suggests a positive inotropic effect of iloprost on a rat model of chronic PAH.