Related Experiment Video
Updated: May 2, 2026
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Diffuse Perfusion Impairment Versus Global Myocardial Flow Reserve and Focal Perfusion Impairments in Patients
Ahmed Sayed1,2, Jonathan B Moody3, Alexis Poitrasson-Rivière3
1Houston Methodist DeBakey Heart and Vascular Center, TX (A.S., M.A., A.E.Y., M.A.R., M.H.A.-M.).
Background:
Although global myocardial flow reserve (MFR) is a powerful prognostic factor, it may overlook segmental abnormalities and does not differentiate focal from diffuse perfusion impairments. Therefore, we sought to assess whether integrated MFR provides incremental prognostic value beyond global MFR.
Methods:
Consecutive patients undergoing positron emission tomography myocardial perfusion imaging between 2019 and 2025 were included. For each patient, global MFR and the proportion of the myocardium with diffuse and focal integrated MFR impairment were quantified. The primary outcome was the total burden of death, myocardial infarction, and heart failure hospitalization. Multivariable Andersen-Gill Cox models with robust variance estimators were used to estimate hazard ratios (HRs). Restricted cubic splines were used to account for potential nonlinearity.
Results:
Over a median follow-up of 550 days (interquartile range, 203-1017 days), 1511 primary outcome events occurred in 8500 patients. In a multivariable model adjusted for both parameters, diffusely impaired integrated MFR (HR per interquartile range, 2.02 [95% CI, 1.33-3.05]), but not global MFR (HR per interquartile range, 1.10 [95% CI, 0.82-1.47]), was associated with poorer outcomes. Diffuse perfusion impairment was more strongly associated with the primary outcome (HR per interquartile range, 2.20 [95% CI, 1.72-2.82]) than focal impairment (HR, 1.25 [95% CI, 1.07-1.46]). Diffusely impaired integrated MFR was more prognostic in patients with a preserved left ventricular ejection fraction (P for interaction <0.001). At ejection fractions of 40%, 50%, 60%, and 70%, the HRs per interquartile range for greater diffuse impairment were 1.43, 1.97, 2.49, and 3.02, respectively.
Conclusions:
Diffuse impairments in myocardial perfusion are associated with poorer outcomes compared with focal impairments and are more informative than global MFR. Diffuse impairments may be more prognostic in patients with a preserved ejection fraction.
Insights
Diffuse myocardial perfusion impairment is more strongly linked to adverse outcomes than global MFR. Integrated MFR, particularly diffuse impairment, offers greater prognostic insight, especially in patients with preserved ejection fraction.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Cardiovascular Imaging
Background:
- Global myocardial flow reserve (MFR) is a key prognostic indicator but may miss localized perfusion issues.
- Integrated MFR assessment can differentiate focal from diffuse impairments, potentially offering more detailed prognostic information.
Purpose of the Study:
- To determine if integrated MFR provides prognostic value beyond global MFR.
- To compare the prognostic impact of diffuse versus focal integrated MFR impairment.
Main Methods:
- Positron emission tomography myocardial perfusion imaging was used in 8500 patients.
- Global MFR and proportions of diffuse/focal integrated MFR impairment were quantified.
- Cox models assessed outcomes (death, MI, HF hospitalization) with robust variance estimation.
Main Results:
- Diffusely impaired integrated MFR (HR 2.02) was associated with poorer outcomes, unlike global MFR (HR 1.10).
- Diffuse perfusion impairment (HR 2.20) was more prognostic than focal impairment (HR 1.25).
- Integrated MFR's prognostic value was greater in patients with preserved ejection fraction.
Conclusions:
- Diffuse myocardial perfusion impairments are more prognostic than global MFR.
- Integrated MFR, especially diffuse impairment, provides incremental prognostic value.
- Preserved ejection fraction may enhance the prognostic significance of diffuse MFR impairment.
