Predicting revascularization using 15O-H2O PET myocardial perfusion imaging - impact of atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Background Myocardial perfusion imaging (MPI) by 15O-H2O positron emission tomography (PET) has excellent diagnostic accuracy for detecting significant coronary stenoses and consequently revascularization in patients with angina and no previous coronary artery disease (CAD). However, arrhythmias such as atrial fibrillation (AF) are thought to reduce myocardial perfusion globally and thresholds indicating ischemic CAD are therefore likely lower in patients with AF. Purpose To determine the ability of 15O-H2O PET MPI to predict subsequent revascularization in patients with known AF and angina. Methods We prospectively included 330 patients with angina and persistent or paroxysmal AF referred for rest/stress 15O-H2O MPI prior to possible angiography and revascularization. 55% of patients had previously documented CAD (181 patients with CAD and 149 with no CAD), and 41% had AF at the time of the MPI (136 patients with AF and 194 with sinus rhythm (SR)). Thus, patients were divided into four groups (SR-noCAD, AF-noCAD, SR-CAD, AF-CAD) to determine the independent impact of AF on myocardial blood flow (MBF). Primary outcome parameters were hyperemic MBF and revascularization within 3 months of the MPI. Results As expected, MBF was significantly affected by the presence of both AF and CAD [MBF (ml/g/min): 2.77 +/- 0.93 (SR-noCAD) vs. 2.10 +/- 0.93 (AF-noCAD) vs. 2.22 +/- 0.93 (SR-CAD) vs. 1.80 +/- 0.74 (AF-CAD), ANOVA p<0.001]. In total, 37 patients (50 coronary vessels) were subsequently revascularized. ROC-analysis of vessel specific hyperemic MBF yielded the following optimal MBF cut-offs (ml/g/min) to predict early revascularization: SR-noCAD: 2.03 (AUC 0.95, p<0.001); AF-noCAD: 1.16 (AUC 0.79, p<0.001); SR-CAD: 1.45 (AUC 0.77, p<0.001); AF-CAD: 1.28 (AUC 0.88, p<0.001). Conclusion Hyperemic MBF was approximately 20 % lower for patients with AF regardless of known CAD status. Despite this, the overall ability of 15O-H2O MPI to predict subsequent revascularization was high in this single centre setup, although the presence of AF and/or documented CAD at the time of the PET decreases the diagnostic accuracy moderately.