Autonomic Neuropathy Influences Great Toe Blood Pressure

doi:10.2337/diacare.17.4.284

Autonomic Neuropathy Influences Great Toe Blood Pressure

Department of Endocrinology, Catholic University of Rome
Internal Medicine, Department of Surgery, Catholic University of Rome
University of Rome “Tor Vergata”; and the Departments of Internal Medicine, Catholic University of Rome
Neurology, Catholic University of Rome

Address correspondence and reprint requests to Luigi Uccioli, MD, Cattedra di Endocrinologia, Dipartimento di Medicina Interna, Universita di Roma “Tor Vergata,” c/o Divisione Malattie Metaboliche, Complesso Intergrato Columbus via della Pineta Sacchetti, 506 00168 Rome, Italy.

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.