[Relationships between baroreflex gain and pulsatile stress in type 1 diabetic patients]

Cardiovascular autonomic neuropathy (CAN) and early arterial stiffness are frequent complications in type 1 diabetes. The aim of our work is to study the relationships between CAN (estimated by baroreflex gain calculation) and arterial stiffness (estimated by pulsatile stress) in type 1 diabetic patients.

In a cross-sectional study, we calculated baroreflex gain and pulsatile stress in 167 type 1 diabetic patients and 160 matched non-diabetic subjects whose blood pressure was continuously monitored with a Finapres(®) device in a postural test (squatting test). The baroreflex gain was calculated by plotting the pulse intervals (R-R) against systolic blood pressure values during the transition phase from squatting to standing. Pulsatile stress was estimated by the pulse pressure×heart rate product. In a longitudinal study, the baroreflex gain and pulsatile stress were calculated before and after a mean follow-up of 79±33 months in type 1 diabetic patients.

Cross-sectional data showed a decrease in baroreflex gain and an increase in pulsatile stress in type 1 diabetic patients versus the matched non-diabetic subjects. A significant correlation between the baroreflex gain and pulsatile stress was present. Type 1 diabetic patients with lower baroreflex gain had a higher value of pulsatile stress when compared to those with higher baroreflex gain. During follow-up, a significant reduction in baroreflex gain (but without significantly increased pulsatile stress) was observed. A univariate analysis showed that the decrease of the baroreflex gain is not correlated with the time interval between the two tests, neither type 1 diabetes duration nor mean glycated hemoglobin values, but significantly with the pulsatile stress increase.

In type 1 diabetic patients, the baroreflex gain is decreased and the pulsatile stress is increased when these markers are compared to age-matched non-diabetic subjects. There is a relationship between indices of CAN and arterial stiffness. Nevertheless, the baroreflex gain (marker of CAN) is impaired earlier than the pulsatile stress in this type 1 diabetic population with inadequate glycaemic control.