Flurpiridaz- new tracer for PET myocardial perfusion imaging facilitates CAD detection in obese women

For decades, Myocardial perfusion imaging (MPI) with single photon emission computed tomography (SPECT) has been the main method for assessing patients with known or suspected coronary artery disease (CAD). However, recently positron emission tomography (PET) MPI is increasingly favored when it is available. In contrary currently available PET perfusion tracers have limitations that have hampered broad utilization.

A recent trial published in Journal of American College of Cardiology reports Flurpiridaz F-18 (flurpiridaz) is a novel positron emission tomography (PET) myocardial perfusion imaging tracer. The trial in second phase suggests flurpiridaz has efficient utility as a new tracer for CAD detection, specifically in women and obese patients.

The current study is a continuation study to further assess the diagnostic efficacy and safety of flurpiridaz for the detection and evaluation of coronary artery disease (CAD) defined as ≥50% stenosis by quantitative invasive coronary angiography (ICA). In this second phase 3 prospective multicenter clinical study, 730 patients with suspected CAD from 48 clinical sites in the United States, Canada, and Europe were enrolled. Patients underwent 1-day rest/stress flurpiridaz PET and 1- or 2-day rest-stress Tc-99m–labeled single photon emission computed tomography (SPECT) before ICA. PET and SPECT images were read by 3 experts blinded to clinical and ICA data.

The key findings of the study are

• A total of 578 patients (age 63.7 ± 9.5 years) were evaluable; 32.5% were women, 52.3% had body mass index ≥30 kg/m2, and 33.6% had diabetes.

• Flurpiridaz PET met the efficacy endpoints of the study; its sensitivity and specificity were significantly higher than the prespecified threshold value by 2 of the 3 readers.

• The sensitivity of flurpiridaz PET was higher than SPECT (80.3% vs 68.7%; P = 0.0003) and its specificity was noninferior to SPECT (63.8% vs 61.7%; P = 0.0004).

• PET area under the receiver-operating characteristic curves were higher than SPECT in the overall population (0.80 vs 0.68; P < 0.001), women, and obese patients (P < 0.001 for both).

• Flurpiridaz PET was superior to SPECT (P < 0.001) for perfusion defect size/severity evaluation, image quality, diagnostic certainty, and radiation exposure. Flurpiridaz PET was safe and well tolerated.

Researchers concluded that “This second flurpiridaz PET myocardial perfusion imaging trial shows that flurpiridaz has utility as a new tracer for CAD detection, specifically in women and obese patients.”

Reference: Maddahi J, Agostini D, Bateman T, et al. Flurpiridaz F-18 PET Myocardial Perfusion Imaging in Patients With Suspected Coronary Artery Disease. J Am Coll Cardiol. 2023 Oct, 82 (16) 1598–1610.https://doi.org/10.1016/j.jacc.2023.08.016.