Diabetes Care, Vol 16, Issue 2 476-482, Copyright © 1993 by American Diabetes Association
Cerebral and ophthalmic artery hemodynamic responses in diabetes mellitus
SG Albert, CR Gomez, S Russell, BR Chaitman, M Bernbaum and BA Kong
Department of Internal Medicine, St. Louis University School of Medicine, MO 63104.
OBJECTIVE--To address whether hemodynamic responses in the cerebral
arteries and OAs may be altered in patients with diabetic retinopathy. We
used TCD to evaluate the effects of changes in BP, posture, and exercise on
MCA and OA blood flow velocities. RESEARCH DESIGN AND METHODS--We evaluated
13 patients with BDR, 19 with PDR, and 11 control subjects. Each was tested
while supine, breathing 100% oxygen, sitting, and during exercise.
RESULTS--Control subjects exhibited linear increases in velocity in the MCA
and OA with increases in BP. Those with BDR had higher baseline sBP than
control subjects. The MCA velocity response to BP in the BDR group was
parallel to, but differed significantly from, the response in control
subjects in compensation for the level of BP (ANCOVA F1,53 = 10.1, P =
0.003). The OA velocity response to BP was indistinguishable between the
control subjects and the group with BDR. The group with PDR had more
elevated BP than control subjects, and those with BDR had more advanced
autonomic neuropathy. The PDR group had heterogenous velocity responses in
the MCA and OA with respect to BP. None of the control subjects and 3 of 13
of the BDR group had abnormal autoregulatory velocity responses in the MCA
or OA to 100% oxygen breathing, whereas 12 of 19 PDR patients were abnormal
(P < 0.01). Of those with PDR, 4 had elevated MCA and 3 had elevated OA
velocities while supine at rest. CONCLUSIONS--Patients with PDR
demonstrated abnormal hemodynamic responses of the cerebral and ophthalmic
circulation both at rest and with exercise.