Worse glycemic control is associated with an impaired arterial energy transfer pattern in elderly with diabetes

Abstract

Abstract Background Worse glycaemic control is known to exacerbate endothelial insult, increasing macro- and microvascular complication risks in diabetes. Impaired intracranial haemodynamics have been frequently reported in patients with diabetes alongside with malperfusion causing structural abnormalities, and poor cognitive and cortical functionality (1-2).Assessment of the alterations in energy transfer characteristics derived from hemodynamic signals may provide novel mechanistic information about how worse glycaemic control may affect cerebrovascular perfusion. Wave reflection index(WRI) is a previously proposed measure of arterial energy transfer efficiency which reflects distal impedance mismatch(3-4). Purpose We aim to interrogate potential relationship between a worse glycaemic control and a less efficient arterial energy transfer, which could enhance our understanding of the cerebrovascular-cortical functional coupling on a mechanistic basis in elderly with diabetes. Methods Left middle cerebral artery wave intensity (WI) was computed with arterial blood pressure and flow velocity (transcranial Doppler) signal as previously described (WI = (dP/dt)*(dU/dt)) (Figure 1). Standard statistical tests were used to interrogate the relationship between glycated haemoglobin levels (HbA1c) and WI parameters. Results In 36 patients with diabetes mellitus type-2 (DM2) (mean age = 65.7 ± 8.8 years), backward compression wave intensity (BCWI) and wave reflection ratio (WRI= BCWI/FCWI) were significantly correlated with HbA1c levels before (rBCWI: 0.409 pBCWI:0.013; rWRI:0.345 pWRI:0.040) and after (rBCWI: 0.410 pBCWI:0.018, rWRI:0.351 pWRI:0.045) adjusting for age, sex and mean arterial pressure (Figure 2). Conclusion(s) In elderly patient with DM2, higher HbA1c values indicating worse glycaemic control are significantly correlated with altered cerebrovascular energy transfer characteristics as assessed by MCA wave intensity analysis. Continuous relationship between worse glycaemic control and higher wave reflection index (a measure of less efficient energy transfer in arterial system and distal impedance mismatch) may imply that the use of energy transfer related indices alongside with conventional hemodynamic indices may help providing a more comprehensive pathophysiological understanding about how cardiovascular risk factors interfere with perfusion.Computation of Wave IntensityMain Results