Diagnostic Value of Quantitative PET/CT Measures of Myocardial Blood Flow and Coronary Flow Reserve for the Assessment of Hemodynamic Significance of Coronary Stenoses

Margarita G. Shavman, Leo A. Bockeria, Irakliy P. Aslanidis , Irina V. Shurupova , Tatiana A. Trifonova, Irina V. Ekaeva

A.N. Bakoulev Scientific Center for Cardiovascular Surgery, Moscow, Russia

Date, time and location: 2018.05.27 08:30, Congress Hall, 2F–A

Abstract

Objective Cutoff values of coronary flow reserve (CFR) and stress myocardial blood flow (MBF) by ¹³N-ammonia PET/CT for the assessment of hemodynamic significance of coronary stenoses vary in different clinics, even if the same radiopharmaceutical is used. Therefore the purpose of our study was to determine cutoff values for stress MBF and CFR for the detection of obstructive coronary artery disease (CAD).

Methods 56 patients with known CAD (mean age 64±8 years) underwent dynamic ¹³N-ammonia stress-PET/CT and invasive coronary angiography (ICA). All patients had significant (>50%) stenoses of one or more coronary arteries (CA) confirmed by ICA. The absolute values of stress and rest MBF and CFR were derived by dynamic PET/CT. CFR was defined as the ratio of stress MBF to rest MBF. Exclusion criteria were coronary artery bypass graft surgery and presence of scar tissue defined by echocardiography or perfusion ¹³N-ammonia stress-PET/CT.

Results We analyzed 146 CA: 74 arteries with the presence of significant (>50%) stenoses confirmed by ICA, 72 arteries – without stenoses. The optimal cutoff values for stress MBF and CFR were calculated using a receiver-operating-characteristic (ROC) curve analysis. The optimal cutoff value for stress MBF was <1,98 ml/min/g and for CFR was <2,39 and there was a very good quality of the model: the area-under-the-ROC curve for MBF (0,85; 95% CI 0,78-0,91) and CFR (0,87; 95% CI 0,81-0,92). In our study the diagnostic performance of stress MBF and CFR for the diagnosis of obstructive CAD on per-vessel basis was equal: sensitivity 74%, specificity 81%, positive predictive value 80%, negative predictive value 75% and accuracy 77%.

Conclusion Dynamic ¹³N-ammonia stress-PET/CT is a highly sensitive and specific method for the assessment hemodynamic significance of coronary stenoses. Stress MBF and CFR are equal complementary quantitative measures and have the same diagnostic value.