iMFR assessment: diffuse atherosclerosis and microvascular dysfunction are more strongly associated with mortality than focally impaired perfusion

Description:
This study focuses on the prognostic value of integrated Myocardial Flow Reserve (iMFR), a novel noninvasive approach designed to help identify microvascular disfunction, coronary artery disease and assess mortality risk.

The researchers analyzed a comprehensive single-center registry encompassing 6,867 patients who underwent rest-stress myocardial perfusion positron emission tomography. They evaluated four perfusion measures: global stress myocardial blood flow (MBF), global myocardial flow reserve (MFR), and two new metrics derived from iMFR focally and diffusely impaired perfusion extents.

Over a median follow-up of 3.4 years, the study found that all perfusion measures were independently associated with mortality risk, but diffusely impaired perfusion extent and global MFR emerged as the strongest mortality predictors. Conversely, focally impaired perfusion was only moderately linked to mortality. The findings suggest that diffusely impaired perfusion extent significantly improves risk stratification when combined with global MFR.

Clinical Relevance:
For medical practitioners, this study introduces iMFR as a powerful prognostic tool that offers better differentiation of CAD types, significantly enhancing patient risk assessment. The key takeaway is that the extent of diffusely impaired perfusion stands out as a superior indicator of mortality risk, outperforming traditional measures like stress MBF and even global MFR. This means that patients exhibiting widespread perfusion impairment could be flagged for more intensive monitoring and possibly earlier, more aggressive intervention.

Partners in Research:
INVIA Medical Imaging Solutions, Houston Methodist, Northwestern University, and the University of Michigan collaborated on this research.

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