Positron Emission Tomography (PET) is a common tool used in nuclear medicine imaging and has gained immense popularity among health professionals over the years.
Two of the most commonly employed radiopharmaceuticals for the test include [11C] Acetate and [18F] Fluorodeoxyglucose (FDG). Out of the two, [11C] Acetate has been employed mostly in cardiology to study oxygen metabolism in myocardial muscles and myocardial perfusion studies. [18F] Fluorodeoxyglucose (FDG) has a wide spectrum of applications that include oncology, infection, inflammation, blood-brain perfusion scans and epilepsy.
Recently, scientists have begun to examine patients with pulmonary arterial hypertension (PAH) and to rate patient improvements in response to drugs as a measure of cardiac metabolism and imaging studies – comparing patients with PAH and right ventricular dysfunction and those with PAH but without right ventricular dysfunction.
Both [11C] Acetate and [18F] Fluorodeoxyglucose (FDG) are excellent markers of glucose metabolism in the heart, lungs and brain. Both radiopharmaceuticals are associated with tissue uptake of glucose and subsequent oxidative metabolism, after which the molecules retain the radio-isotope and cannot be utilized further, which then makes them a useful markers to assess the rate of metabolism and correlate it with cardiac and pulmonary health.
This phenomenon, along with cardiac magnetic resonance imaging (MRI) scans, is to be employed to test the efficacy of the drug ranolazine on PAH patients, by scientists at the University of Pennsylvania in collaboration with the Cardiovascular Medical Research and Education Fund, Brigham and Women’s Hospital, University of Maryland, Yale University and Washington University School of Medicine.
The study officially titled “A randomized, double-blind, placebo controlled, multi-center study to assess the effect of ranolazine on outcomes in subjects with pulmonary hypertension and right ventricular dysfunction accompanied by a comparative study of cellular metabolism in subjects with pulmonary hypertension with and without right ventricular dysfunction” aims to enroll 36 patients with PAH (with and without right ventricular dysfunction). The patients will receive a fixed dose of ranolazine and will undergo imaging studies at the beginning and the end (week 26) of the trial.
For every PET/CT imaging session, subjects will receive a 15-25 millicurie intravenous injection of[11C] Acetate and a 10 millicurie injection of [18F] FDG. At baseline and 6 months follow up, a cardiac MRI will be performed.
The study aims first to compare myocardial oxygen consumption, FDG uptake, and myocardial perfusion at baseline for subjects with normal right ventricular function and those with persistent right ventricular dysfunction. A secondary goal is to access change from baseline in myocardial oxygen consumption and FDG uptake and myocardial perfusion in subjects with persistent right ventricular dysfunction who are treated with ranolazine or placebo.
The study could be completed by September 2016.