Haemodynamic changes during a squat test, pulsatile stress and indices of cardiovascular autonomic neuropathy in patients with long-duration type 1 diabetes.
OBJECTIVE
Cardiovascular autonomic neuropathy (CAN) and pulsatile stress are considered to be independent cardiovascular risk factors. This study compared haemodynamic changes during an active orthostatic test in adult patients with type 1 diabetes (T1DM), using low versus high RR E/I ratios as a marker of CAN.


METHODS
A total of 20 T1DM patients with low RR E/I ratios were compared with 20 T1DM patients with normal RR E/I ratios, matched for gender (1/1 ratio), age (mean: 46 years) and diabetes duration (22-26 years); 40 matched healthy subjects served as controls. All subjects were evaluated by continuous monitoring of arterial blood pressure (Finapres(®)) and heart rate using a standardized posture test (1-min standing, 1-min squatting, 1-min standing), thus allowing calculation of baroreflex gain.


RESULTS
Compared with controls, T1DM patients showed lower RR E/I ratios, reduced baroreflex gains, higher pulsatile stress (pulse pressure×heart rate), greater squatting-induced pulse pressure rises, orthostatic hypotension and reduced reflex tachycardia. Compared with T1DM patients with preserved RR E/I ratios, T1DM patients with low RR E/I ratios showed reduced post-standing reflex tachycardia and baroreflex gain, and delayed blood pressure recovery, but no markers of increased pulsatile stress. Interestingly, decreased baroreflex gain was significantly associated with both pulsatile stress and microalbuminuria.


CONCLUSIONS
The use of RR E/I ratios to separate T1DM patients allows the detection of other CAN markers during an orthostatic posture test, but with no significant differences in pulsatile stress or microalbuminuria. In this context, squatting-derived baroreflex gain appears to be more informative.
CHU Sart Tilman, University of Liège, Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine, 4000 Liège, Belgium.
J-C
JC
Philips
M
M
Marchand
A J
AJ
Scheen
D000328:Adult; D000704:Analysis of Variance; D017704:Baroreflex; D001794:Blood Pressure; D002318:Cardiovascular Diseases / Q000097:blood / Q000503:physiopathology* / Q000628:therapy; D016022:Case-Control Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000503:physiopathology* / Q000628:therapy; D003929:Diabetic Neuropathies / Q000097:blood / Q000503:physiopathology* / Q000628:therapy; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D007024:Hypotension, Orthostatic / Q000097:blood / Q000503:physiopathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011187:Posture; D013610:Tachycardia / Q000209:etiology; D013997:Time Factors; D055815:Young Adult