{
  "abstract": "Background Coronary artery disease (CAD) results in reduced myocardial blood flow (MBF) and ischaemia. Patients with CAD often have impaired functional capacity and are at risk of developing heart failure. However, the relationship between ischaemia and cardiac function is poorly understood. Advancements in cardiac MRI now permit quantification of MBF from stress-perfusion imaging. Moreover, 4D Flow CMR can be used to comprehensively examine cardiac function with kinetic energy (KE) assessment. KE represents the energy that blood possesses due to its motion and could represent an important hemodynamic parameter. The aim of this study was to explore the relationship between MBF and parameters of LV function using 4D flow CMR imaging in patients with stable angina.Methods Patients with chronic coronary syndromes (CCS) underwent CMR imaging on a 1.5T GE system. The CMR protocol included cine imaging, first pass stress-perfusion and whole heart 4D flow. Relative flow components and multiple phasic KE assessment of the LV was performed ( figure 1). All KE parameters were indexed to left ventricular end diastolic volume (EDV). MBF was quantified from stress perfusion images and indexed to myocardial mass. All analysis was performed using MASS software (Leiden University Medical Centre). The correlation between MBF and parameters of LV function was assessed by calculating the Pearson’s correlation coefficient.Results Twenty-nine patients were included. Average age was 72 years (±10.5) and 75.9% were male. Full baseline demographics are displayed in table 1. Average stress MBF was 3.31 (±0.82) ml/min/g. Of these, eighteen patients had full 4D flow datasets available for analysis. There was a moderate correlation between MBF and average KEiEDV (R=0.43) and average diastolic KEiEDV (R=0.53) compared to a weak correlation with EF (R=0.11), LV global longitudinal strain (R=-0.18) and LV circumferential strain (R=0.15) (figure 2). Correlation coefficients for all parameters assessed are displayed in table 2.Conclusions In this small cohort of patients with CCS, there was a moderate correlation between MBF and average KEiEDV and average diastolic KEiEDV compared to a weak correlation between MBF and standard parameters of cardiac function including EF and global longitudinal strain. 4D flow CMR assessment of left ventricular kinetic energy may therefore be a more representative indicator of ischaemia-induced cardiac dysfunction than standard metrics. Further work is required to determine the impact of revascularisation on these parameters and the relationship with functional capacity.Abstract 6-018 Table 1Patient demographics Number (%) or mean (± SD) Male 22 (75.9%) Age (years) 72 (±10.5) BMI (kg/m2) 28.7 (±4.4) Smoker 13 (44.8%) Hypertension 18 (62.1%) Type 2 Diabetes Mellitus 1 (3.5%) BMI = body mass indexAbstract 6-018 Table 2Assessment of parameters of cardiac function and correlation with stress myocardial blood flow Parameter Mean (± SD) Correlation co-efficient Left ventricular ejection fraction (%) 57.7 ± 9.0 0.11 E/A ratio 1.5 ±1.2 0.28 Left ventricular global longitudinal strain (%) -16.1 ± 3.6 -0.18 Left ventricular circumferential strain (%) -21.9 ± 9.2 0.15 Average RR KEiEDV (µJ/mL) 10.5 ± 3.1 0.43 Average diastolic KEiEDV (µJ/mL) 10.5 ± 3.2 0.54 Average systolic KEiEDV (µJ/mL) 11.1 ± 3.9 0.20 Mean direct blood flow KEiEDV (µJ/mL) 6.8 ±3.1 0.26 KEiEDV = Kinetic energy indexed to end diastolic volume, MBF = myocardial blood flow, SD = standard deviationAbstract 6-018 Figure 1Example of LV kinetic energy assessmentA representative example of left ventricular kinetic energy assessment demonstrating direct (green), residual (red), retained (yellow) and delayed (blue) flow components in the long axis (Panel A) and a representative time curve illustrating the typical systolic and diastolic KE components (Panel B).Abstract 6-018 Figure 2Correlation between MBF and parameters of LV functionScatter plots demonstrating the correlation between stress MBF and EF (panel A, R=0.11) and average and diastolic KEiDV (Panel B, R= 0.43 and 0.54 respectively). MBF = myocardial blood flow. KEiEDV = Kinetic energy",
  "authors": [
    {
      "affiliations": [
        "Division of Clinical Medicine, School of Medicine & Population Health, University of Sheffield, Sheffield, UK"
      ],
      "name": "Megan Rendell"
    },
    {
      "affiliations": [
        "Division of Clinical Medicine, School of Medicine & Population Health, University of Sheffield, Sheffield, UK"
      ],
      "name": "Ronald Manorekang"
    },
    {
      "affiliations": [
        "Division of Clinical Medicine, School of Medicine & Population Health, University of Sheffield, Sheffield, UK"
      ],
      "name": "Gareth Williams"
    },
    {
      "affiliations": [
        "Division of Clinical Medicine, School of Medicine & Population Health, University of Sheffield, Sheffield, UK"
      ],
      "name": "Abdulaziz Al-Baraikan"
    },
    {
      "affiliations": [
        "Division of Clinical Medicine, School of Medicine & Population Health, University of Sheffield, Sheffield, UK",
        "Department of Cardiology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK"
      ],
      "name": "Thomas Newman"
    },
    {
      "affiliations": [
        "Division of Clinical Medicine, School of Medicine & Population Health, University of Sheffield, Sheffield, UK",
        "Department of Cardiology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK",
        "NIHR Biomedical Research Centre, Sheffield, UK"
      ],
      "name": "Julian Gunn"
    },
    {
      "affiliations": [
        "Division of Clinical Medicine, School of Medicine & Population Health, University of Sheffield, Sheffield, UK",
        "Department of Cardiology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK",
        "NIHR Biomedical Research Centre, Sheffield, UK"
      ],
      "name": "Paul Morris"
    },
    {
      "affiliations": [
        "Division of Clinical Medicine, School of Medicine & Population Health, University of Sheffield, Sheffield, UK",
        "Department of Cardiology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK",
        "NIHR Biomedical Research Centre, Sheffield, UK"
      ],
      "name": "Rebecca Gosling"
    }
  ],
  "title": "6-018 Exploring the relationship between myocardial blood flow and left ventricular blood flow kinetic energy",
  "uid": "610deff5-ee15-53ce-88c9-0ea2b4c29f2e"
}