Prevalence of impaired flow-mediated epicardial vasodilation among different types of coronary flow regulation

Figures

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  Fig. 1. Normal Myocardial Perfusion, Global Myocardial Flow Reserve (MFR), and Myocardial Blood Flow (MBF) Study with 13N-ammonia PET/CT. This 44-year-old woman presented with atypical chest discomfort, and dyslipidemia. There is normal and homogenous 13N-ammonia uptake of the left ventricle at rest and regadenoson-stress PET/CT count images with corresponding normal myocardial perfusion on polar map display widely ruling out hemodynamically significant obstructive CAD (right panel). Regional MBF quantification denotes normal hyperemic MBFs and MFR in all three major coronary artery territories of the LAD, LCx, and RCA with a global hyperemic MBF of 2.89 mL/g/min, global rest MBF of 0.84 mL/g/min, and corresponding global MFR of 3.43 signifying normal coronary microvascular function (nCMF) (middle panel). Subsequently, longitudinal MBFs in the mid to mid-to-distal myocardial segments of the LV corresponding to the vascular territories of the LAD (segments:7–8 and 13–14), Lcx (segments:11–12 and 16), and RCA (segments:9–10 and 15) were determined applying a 17-segment model. In this case, LAD mid-segments 7 and 8 with stress MBF of 3.2 and 2.7 mL/g/min (mean:2.95 ml/g/min), but without a…

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  Fig. 2. Normal Myocardial Perfusion, Global MFR but Abnormal Hyperemic Longitudinal MBF Gradient with 13N-ammonia PET/CT. This 68-year-old woman presented with atypical chest discomfort, dyslipidemia and arterial hypertension. As can be appreciated, there is widely normal and homogenous 13N-ammonia uptake of the left ventricle at rest and regadenoson-stress PET/CT count images with corresponding normal myocardial perfusion on polar map display widely excluding significant flow-limiting obstructive focal CAD (right panel). Regional MBF quantification denotes normal hyperemic MBFs and MFR in all three major coronary artery territories of the LAD, LCx, and RCA with a global hyperemic MBF of 2.45 mL/g/min, global rest MBF of 0.99 mL/g/min, and corresponding global MFR of 2.48 signifying normal nCMF (middle panel). Subsequently, longitudinal MBFs in the mid to mid-to-distal myocardial segments of the LV corresponding to the vascular territories of the LAD (segments:7–8 and 13–14), Lcx (segments:11–12 and 16), and RCA (segments:9–10 and 15) were determined applying a 17-segment model. In this patient, LAD mid-segments 7 and 8 with stress MBF of 2.7 and 2.7 mL/g/min (mean:2.7 ml/g/min) with a…

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  Fig. 3. Prevalence and Distribution of Abnormal Hyperemic Longitudinal MBF Gradient among Groups. Highest prevalence of abnormal longitudinal MBF gradient or an impairment of flow-mediated epicardial vasodilation is observed in group 1 with nCMF, followed by group 2 with classical type of CMD and group 3 with endogen type of CMD, respectively

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  Fig. 4. Hyperemic Longitudinal MBF Gradient among Groups. As can be appreciated, the extent of abnormal hyperemic longitudinal MBF gradient was more pronounced in group 1 with nCMF and group 3 with endogen type of CMD when compared to group 2 with classical CMD, while it was comparable between group 1 and group 3

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  Figs. 5. Correlation between Global Hyperemic MBF and MBF Gradients. Figure 5a denotes the correlation between global hyperemic MBF and corresponding abnormal longitudinal MBF gradient. In addition, Fig. 5b demonstrates that the global hyperemic MBF also associates with the corresponding ∆longitudinal MBF gradient (longitudinal MBF gradient during pharmacologic stress - longitudinal MBF gradient at rest)

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  Figs. 6. Correlation between Global Myocardial Flow Reserve (MFR) and MBF Gradients. Figure 6a unravels a significant association between the global MFR and corresponding abnormal hyperemic longitudinal MBF gradient. Further, Fig. 6b signifies that the global MFR also correlates with the corresponding ∆longitudinal MBF gradient (longitudinal MBF gradient during pharmacologic stress - longitudinal MBF gradient at rest). Central Illustration: Assessment of Global MBF and Hyperemic Longitudinal MBF Gradient with 13N-ammonia PET/CT Legend: nCMF = normal coronary microvascular function; CMD = coronary microvascular dysfunction, group 1 = normal coronary microvascular function; group 2 = classical type of CMD; group 3 = endogen type of CMD; MFR = myocardial flow reserve; MBF = myocardial blood flow