Pronounced skin capillary ischemia in the feet of diabetic patients with bad metabolic control

Abstract

Skin capillary circulation is impaired during postocclusive reactive hyperaemia (PRH) in toes of diabetic patients independent of diabetes duration and macrocirculation. The aim of this study was to examine its relation to metabolic control. The skin microcirculation was investigated in 20 patients with insulin-dependent diabetes mellitus: 10 patients with bad [HbA1c > 7.5 (8.7 +/- 0.8) %], and 10 patients with good metabolic control [HbA1c < 7.5 (6.3 +/- 1.0) %]. The diabetes duration was similar in both groups (16 +/- 9 and 16 +/- 6 years, respectively). None had macroangiopathy. Thirteen healthy subjects served as controls. The capillary blood cell velocity (CBV) in the nailfold of the great toe was investigated by videophotometric capillaroscopy, and the total skin microcirculation by laser Doppler fluxmetry (LDF). CBV and LDF were studied during rest and after 1-min arterial occlusion. The vibration perception thresholds (VPT) of the feet were higher (p < 0.05) in the patients with bad (34 +/- 12 V), as compared to patients with good metabolic control (18 +/- 10 V) and to healthy subjects (13 +/- 3 V). Peak CBV during PRH was reduced in both patient groups (p < 0.01), and lowest in the patients with bad metabolic control (p < 0.05). Time to peak CBV was prolonged (p < 0.01) in the patients with bad, while normal in the patients with good metabolic control. LDF was similar in all groups. An inverse correlation was found between HbA1c and peak CBV during PRH (r = 0.60; p = 0.008), while positive correlations were found to time to peak CBV (r = 0.62; p = 0.004) and VPT (r = 0.60; p = 0.01). No associations were seen between VPT and the microcirculatory variables. The results indicate that the metabolic control is of importance for the nutritive capillary circulation and the peripheral nerve function in the diabetic foot.