Integrated myocardial flow reserve (iMFR) assessment: diffuse atherosclerosis and microvascular dysfunction are more strongly associated with mortality than focally impaired perfusion

• Published in: European journal of nuclear medicine and molecular imaging 2023-12, Vol.51 (1), p.123-135
• Main Authors: Moody, Jonathan B., Poitrasson-Rivière, Alexis, Renaud, Jennifer M., Hagio, Tomoe, Al-Mallah, Mouaz H., Weinberg, Richard L., Ficaro, Edward P., Murthy, Venkatesh L.
• Format: Article
• Language: English
• Subjects: Arteriosclerosis; Atherosclerosis; Blood flow; Cardiology; Constriction, Pathologic; Coronary Artery Disease - diagnostic imaging; Coronary Circulation; Death; Emission analysis; Evaluation; Fractional Flow Reserve, Myocardial; Hazard assessment; Heart diseases; Humans; Imaging; Ischemia; Medical imaging; Medicine; Medicine & Public Health; Microvasculature; Mortality; Myocardial ischemia; Myocardial Perfusion Imaging - methods; Nuclear Medicine; Oncology; Original Article; Orthopedics; Perfusion; Positron emission; Positron emission tomography; Quartiles; Radiology; Reclassification; Risk factors; Signs and symptoms
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-023-06448-1

Background and aims Although treatment of ischemia-causing epicardial stenoses may improve symptoms of ischemia, current evidence does not suggest that revascularization improves survival. Conventional myocardial ischemia imaging does not uniquely identify diffuse atherosclerosis, microvascular dysfunction, or nonobstructive epicardial stenoses. We sought to evaluate the prognostic value of integrated myocardial flow reserve (iMFR), a novel noninvasive approach to distinguish the perfusion impact of focal atherosclerosis from diffuse coronary disease. Methods This study analyzed a large single-center registry of consecutive patients clinically referred for rest-stress myocardial perfusion positron emission tomography. Cox proportional hazards modeling was used to assess the association of two previously reported and two novel perfusion measures with mortality risk: global stress myocardial blood flow (MBF); global myocardial flow reserve (MFR); and two metrics derived from iMFR analysis: the extents of focal and diffusely impaired perfusion. Results In total, 6867 patients were included with a median follow-up of 3.4 years [1st–3rd quartiles, 1.9–5.0] and 1444 deaths (21%). Although all evaluated perfusion measures were independently associated with death, diffusely impaired perfusion extent (hazard ratio 2.65, 95%C.I. [2.37–2.97]) and global MFR (HR 2.29, 95%C.I. [2.08–2.52]) were consistently stronger predictors than stress MBF (HR 1.62, 95%C.I. [1.46–1.79]). Focally impaired perfusion extent (HR 1.09, 95%C.I. [1.03–1.16]) was only moderately related to mortality. Diffusely impaired perfusion extent remained a significant independent predictor of death when combined with global MFR ( p