Autonomic Neuropathy Influences Great Toe Blood Pressure

Abstract

OBJECTIVE To assess the influence of autonomic neuropathy on toe blood pressure (TBP), a parameter used currently as an ischemic index. RESEARCH DESIGN AND METHODS The age-matched study subjects included 20 non-insulin-dependent diabetes mellitus (NIDDM) patients with autonomic neuropathy (DN) and 10 NIDDM patients without autonomic neuropathy (D), assessedby standard cardiovascular tests and galvanic skin response, and 8 control subjects (C). None of the subjects had peripheral vascular disease (PVD) (ankle/brachial index 0.9–1.1. RESULTS The TBP and toe/brachial index (TBI) were significantly lower in DN than in C and D (P < 0.01). The saturation index (SI), the ratiobetween foot venous and arterial partial pressure of oxygen (PO2), was significantly higher in DN than in C and D (P < 0.05). An inverse relationship was found between TBI and SI (r = 0.554, P = 0.001). CONCLUSIONS The autonomic nervous system directly influences peripheral circulation. In diabetic patients without PVD, a failure of sympathetic fibers caused by autonomic neuropathy could lead to a reduction of TBP. Therefore, TBP cannot be used as an ischemic index in diabetic patients.