1350544 - Cardiovascular adaptations to acute hemodynamic stress in type 2 diabetes coexistent with overweight/obesity

Coronary microvascular dysfunction and compromised cardiac energy production have been proposed as pivotal features underpinning diabetic cardiomyopathy(2). The relative associations of impaired cardiac energetics and perfusion to systolic and diastolic subclinical functional changes at rest and in response to acute haemodynamic stress in T2D have not been reported.

Methods:

Using cardiovascular magnetic resonance (CMR) and ³¹phosphorus MR spectroscopy (³¹P-MRS) we assessed changes in cardiac energetics, perfusion, global longitudinal shortening (GLS), systolic and diastolic function in response to increases in cardiac workload with dobutamine stress in T2D patients with overweight/obesity (n=36) and non-athletic healthy volunteers(n=20). Additionally, we compared results against 20 veteran athletes.

Results:

Demographic, biochemical and rest and stress CMR and ³¹P-MRS data are shown in Table-1. T2D patients showed significant reductions in resting energetics compared to the control groups. Increases in RPP with dobutamine stress were similar across study groups.. T2D patients showed significant reductions in GLS and mitral in-flow E/A ratios at rest. During dobutamine stress, all groups showed similar increments in GLS and similar decrements in E/A ratio, but these parameters remained significantly higher in the two control groups. T2D patients showed lower stress MBF than the control groups.

Rest LVEF correlated with rest MBF and stress LVEF correlated stress MBF. While rest energetics correlated with rest E/A ratio and stress energetics correlated with stress E/A ratio, there was no significant correlation between energetics and LVEF. Suggesting links between insulin resistance, myocardial energetics, diastolic function and GLS, triglyceride-index correlated with rest and stress PCr/ATP.

Conclusion:

To the best of our knowledge this is the first study to explore the haemodynamic stress relationships between energetics, myocardial blood flow, strain, LVEF and diastolic function. In response to dobutamine stress, T2D patients with overweight/obesity as well as healthy volunteers and age-matched veteran athletes show decrements in myocardial energetics and diastolic function, and similar increments in GLS and LVEF, but with a blunted increment in stress MBF in T2D patients with overweight/obesity. We showed that rest and stress MBF are associated with rest and stress LVEF, and rest and stress energetics are associated with rest and stress diastolic parameters. Suggesting that diastolic function is a more energetically sensitive process than global systolic function. This study gives important insights into the distinct associations between energetics, perfusion and plasma metabolic parameters with diastolic and systolic function in diabetes with overweight/obesity and support development of patient-specific therapies and monitoring strategies.