Prognostic value of regional myocardial flow reserve derived from 13N-ammonia positron emission tomography in patients with suspected coronary artery disease

Abstract

Purpose To assess the prognostic value of regional quantitative myocardial flow measures as assessed by 13N-ammonia positron emission tomography (PET) myocardial perfusion imaging (MPI) in patients with suspected coronary artery disease (CAD). Methods We retrospectively included 150 consecutive patients with suspected CAD who underwent clinically indicated 13 N-ammonia PET-MPI and who did not undergo revascularization within 90 days of PET-MPI. The presence or absence of a decreased global myocardial flow reserve (i.e., MFR < 2) as well as decreased regional MFR (i.e., ≥ 2 adjacent segments with MFR < 2) was recorded, and patients were classified as having preserved global and regional MFR (MFR group 1), preserved global but decreased regional MFR (MFR group 2), or decreased global and regional MFR (MFR group 3). We obtained follow-up regarding major adverse cardiac events (MACE, i.e., a combined endpoint including all-cause death, non-fatal myocardial infarction, and late revascularization) and all-cause death. Results Over a median follow-up of 50 months (IQR 38–103), 30 events occurred in 29 patients. Kaplan–Meier analysis showed significantly reduced event-free and overall survival in MFR groups 2 and 3 compared to MFR group 1 (log-rank: p = 0.015 and p = 0.013). In a multivariable Cox regression analysis, decreased regional MFR was an independent predictor for MACE (adjusted HR 3.44, 95% CI 1.17–10.11, p = 0.024) and all-cause death (adjusted HR 4.72, 95% CI 1.07–20.7, p = 0.04). Conclusions A decreased regional MFR as assessed by 13 N-ammonia PET-MPI confers prognostic value by identifying patients at increased risk for future adverse cardiac outcomes and all-cause death.

Comparison of the prognostic value of impaired stress myocardial blood flow, myocardial flow reserve, and myocardial flow capacity on low-dose Rubidium-82 SiPM PET/CT

“…4 In contrast, Von Felten et al recently demonstrated using 13 Nammonia, an independent prognostic value of regional MFR \ 2, being superior to global stress MBF and MFR. 26 In the current study, the first using the latest SiPM technology, whose characteristics might offer potential benefits for precise analysis, we found that severe regional per pixel MFC impairment is a powerful predictor of cardiovascular events, independent from traditional cardiovascular risk factors, but not from global perfusion parameters. Although the current study has inherent limitations which could limit the scope of the results, these data support a close relationship between global and regional perfusion.…”

Comparison of the Prognostic Value of Global and Regional Myocardial Flow Capacity Radius, Myocardial Flow Reserve, and Stress Myocardial Blood Flow Using Rubidium-82 with SiPM PET/CT

“…Harjulahti et al found similar results using also [ 15 O]water PET (4). In contrast, Von Felten et al recently demonstrated using 13 N-ammonia, an independent prognostic value of regional MFR < 2, being superior to global stress MBF and MFR (24). In this study the authors emphasized several methodological differences for regional measurements between them: (i) a decrease in at least two adjacent segments, (ii) Bom et al: continuous variables computed as the average MFR values from the two adjacent segments with the lowest values, and (iii) Harjulahti et al: a single segment with stress MBF lower than 2.3 ml/g/min.…”

Impact on cardiovascular outcome of coronary revascularization-induced changes in ischemic perfusion defect and myocardial flow reserve

“…The quantification of absolute MBF and MFR by PET as markers of coronary vascular function provides an incremental value compared to clinical and perfusion data for both diagnostic and prognostic purposes in patients with suspected or known CAD [ 21 – 23 ]. Previous studies pointed up on prognostic value of MFR [ 24 – 27 ], demonstrating that the coronary vasodilator dysfunction is a powerful and independent correlate of cardiac mortality and provides significant incremental risk stratification [ 28 – 30 ]. The presence of reduced cardiac vascular function was associated with an increased risk of cardiac death even in the presence of normal scans by semi-quantitative visual analysis and independently of other risk factors [ 31 – 34 ].…”