Assessment of vascular autonomic function using peripheral arterial tonometry.

Area of Science:

• Cardiovascular Physiology
• Autonomic Nervous System Research
• Diabetic Complications

Background:

• Peripheral autonomic dysfunction is common in diabetic polyneuropathy.
• Non-invasive quantitative assessment of autonomic function remains challenging.
• Reactive hyperemia peripheral arterial tonometry (RH-PAT) is an established endothelial function test.

Purpose of the Study:

• To develop a novel index for evaluating vascular autonomic function.
• To utilize RH-PAT for assessing peripheral sympathetic activity.
• To investigate the utility of this index in diabetic patients.

Main Methods:

• Sixty-five subjects (healthy, sympathetic nerve blockers, diabetic patients) were enrolled.
• RH-PAT was performed with 5-minute unilateral arm blood flow occlusion.
• A novel index, sympathetic hypoemia index (SHI), was derived from post-occlusion pulse amplitude changes.

Main Results:

• The SHI demonstrated a time-dependent increase in healthy subjects, abolished by sympathetic blockade.
• Plasma norepinephrine levels increased significantly post-occlusion.
• SHI showed strong correlation with sympathetic heart rate variability (HRV) parameters and was significantly lower in diabetic patients.

Conclusions:

• The novel sympathetic hypoemia index (SHI) accurately reflects peripheral sympathetic activity.
• SHI, derived from RH-PAT, offers a non-invasive method for assessing vascular autonomic function.
• SHI may be a valuable tool for evaluating diabetic patients with autonomic dysfunction.