Glycaemic control influences peripheral blood flow and haemorheological variables in patients with diabetes mellitus.

Since persistent uncontrolled hyperglycaemia predisposes to vascular complications in diabetics, this study aimed at assessing the relationship of glycaemic control to plasma fibrinogen concentration, relative plasma viscosity and ankle arterial blood flow in diabetic patients with (N = 28) and without neuropathy (N = 34) compared with non-diabetic controls (N = 21). Glycaemic control was determined by total glycated haemoglobin (GHb) levels. Patients were placed into three categories of glycaemic control, namely good (GHb 4 -< 8%), fair (GHb 8-12%) and poor (GHb > 12%).Compared with non-diabetics, blood flow was significantly higher (p < 0.05) in patients with good but not poor glycaemic control. Fibrinogen was significantly higher in patients with fair and poor glycaemic control than in non-diabetic subjects (p < 0.05). In non-neuropathic patients, viscosity was higher (p < 0.05) in those with fair control and significantly different (p < 0.05) between those with fair and poor control. The results suggest that the initial vasodilatation in the periphery is attenuated by poor glycaemic control, contributing to the decrease in ankle arterial blood flow as a consequence of the simultaneous increase in plasma fibrinogen and viscosity. These adverse changes may contribute to the development of the diabetic foot.

Venodynamic and hemorheological variables in patients with diabetes mellitus.

BACKGROUND: The association between diabetes mellitus and the occurrence of peripheral vascular disease has been well established. However, it is unclear whether the venous circulation is also affected. This study was done to determine whether there is impairment of venous function in the legs of patients with diabetes mellitus and the relationship with rheological parameters. METHODS: Venous occlusion plethysmography was used to assess venous circulation in the legs of 54 diabetic patients at the University Hospital of the West Indies. The venodynamic variables measured were segmental venous capacitance (SVC), maximum venous outflow (MVO), and venous emptying time (VET) at the calf, ankle and great-toe. Plasma fibrinogen concentration (PFC), relative plasma viscosity (RPV) and whole blood viscosity (WBV) were measured by standard techniques. RESULTS: Calf SVC was significantly less in neuropathic diabetic patients (ND) than in non-diabetic subjects (C) (p <0.05). MVO at the calf of ND and non-neuropathic diabetic patients (NND) was significantly lower than in C (p <0.05). VET at the ankle and calf were significantly shorter in ND compared with NND (p <0.05). No statistically significant differences in SVC, MVO and VET among the three groups were observed at the great-toe. PFC was significantly higher in diabetic patients than in the control group. No significant differences were detected in WBV at high or low shear rates. CONCLUSIONS: These findings strongly suggest impairment of venous function in the legs of diabetic patients. This impairment of venous function appears to be unrelated to rheological abnormalities.

The influence of persistent hyperglycaemia of hyperfibrinogenaemia and hyperviscosity in diabetes mellitus

The effect of hyperglycaemia on hyperfibrinogenaemia and its consequence on plasma viscosity was investigated in 69 diabetic patients during the course of hypoglycaemic treatment. Glycaemic control was assessed by measurement of glycosylated haemoglobin (HbA). Plasma fibrinogen concentration (PFC) was determined by a clot-weight method. The relative plasma viscosity (RPV) was measured by capillary viscometry. The mean PFC and RPV were significantly (p<0.001) elevated in the diabetic patients as compared with a non-diabetic control group. Both PFC and RPV showed a distinct, step-wise increase with progressively poorer glycaemic control. The data strongly indicate that persistent hyperglycaemia is associated with a frank hyperfibrinogenaemia and hyperviscous plasma in most of the diabetic patients studied. These abnormal haemorrheological changes could impact adversely on both the haemostatic process and circulation in diabetic patients(Au)

Haemorheological and haemodynamic changes in hypertensive diabetics

We measured plasma fibrinogen concentration (PFC), relative plasma viscocity (RPV), and arterial blood flow at the calf, ankle and great-toe in hypertensive and normotensive patients with diabetes compared with non-diabetic age and sex-matched control subjects. Blood flow after reactive hyperaemia at the ankle was also measured. PFC was measured by a clot-weight procedure. RPV was measured by capillary viscometery, and blood flow by venous occlusion plethysmography. (AU)

Haemorheological and haemodynamic changes in hypertensive diabetics

We measured plasma fibrinogen concentration (PFC), relative plasma viscocity (RPV), and arterial blood flow at the calf, ankle and great-toe in hypertensive and normotensive patients with diabetes compared with non-diabetic age and sex-matched control subjects. Blood flow after reactive hyperaemia at the ankle was also measured. PFC was measured by a clot-weight procedure. RPV was measured by capillary viscometery, and blood flow by venous occlusion plethysmography.

Peripheral occlusive arterial disease in diabetic clinic attendees

Peripheral occlusive arterial disease occurs with a greater frequency in the diabetic population than in the general population. It can have debilitating effects and so early detection and intervention are important. The aim of this study was to investigate the prevalence of peripheral occlusive arterial disease (POAD) among a sample of diabetic patients attending the out-patient clinic at the University Hospital of the West Indies (UHWI), Mona. A sphygmomanometer was used to measure arm and ankle blood pressures in 80 diabetic patients, and the ankle-brachial systolic pressure index (ABI) was determined. The presence or absence of peripheral pulses was detected with the Multi-dopplex (model 1). POAD was defined by the absence of one or more peripheral pulses and/or an ABI < 0.09. Of the 80 diabetic patients examined, 18 (22.5 percent) were found to have POAD. Seventy-eight percent of diabetics with POAD had the disease in both legs. Intermittent claudication was diagnosed in 27.7 percent of patients with POAD. A significantly larger proportion of diabetics with POAD were hypertensive and/or neuropathic (p < 0.05). The results suggest that serious attention should be given to the quantitative screening for POAD in the diabetic patients attending the clinic at the UHWI (AU)

The effect of glycaemic control on peripheral blood flow in diabetics -Poster presentation

Many studies have shown that persistent uncontrolled blood glucose predisposes to several diabetic complications. The aim of this study was to determine the influence of blood glycated haemoglobin levels on plasma fibrinogen concentration - (PFC), relative plasma viscosity (RPV) and ankle blood flow (Qak) in a group of diabetic patients with vascular complications compared with non-diabetic control (C). Qak was measured by the technique of venous occlusion plethysmography. PFC was determined by a clot-weight method. RPV was determined by capillary viscometry. Glycaemic control was determined by measuring glycated haemoglobin levels (GHb). Patients were divided into three categories of glycaemic control, namely good (GHb 4 - 8 percent), moderate (GHb > 8 - 12 percent) and poor (GHb > 12 percent). Qak, PFC and RPV were compared among diabetics with and without peripheral occlusive arterial disease (POAD) and/or neuropathy of various categories of glycaemic control. Qak in diabetics without peripheral occlusive arterial disease (POAD) with good glycaemic control was significantly higher (p <0.05) than that of non-diabetic (C). Qak differed significantly (p < 0.05) between non-neuropathic diabetics (without POAD) (D) with good and poor or good and moderate glycaemic control. PFC was significantly higher (p < 0.05) in all diabetics with POAD, in D with moderate glycaemic control and in neuropathic diabetes (without POAD) (ND) with poor control than in C. RPV was significantly higher (p < 0.05) in D with moderate control and poorly controlled neuropathic diabetics with POAD than in C. RPV differed significantly (p < 0.05) between D with moderate and poor control. The results suggest that in the absence of POAD, an initial vasodilatation occurs in diabetics. The decrease in arterial flow as metabolic control worsens, may be a consequence of the simultaneous increase in plasma viscosity.(AU)

Venous function study in diabetics with neuropathy: a preliminary study

In a previous study, we found a significantly impaired vasodilatory reserve, a reflection of abnormal vasodilation in the feet of diabetics with neuropathy. No study has been done to establish whether our diabetics have abnormal venous function. The present study was designed to examine venodynamic variables in order to determine whether venous impairment was present in our diabetic patients. Venous circulation in the leg was examined in 27 diabetic patients with neuropathy (ND) and compared with 35 non-neuropathic diabetics (NND) and 19 non-diabetic controls (C). Patients and controls were free from signs and symptoms of peripheral occlusive arterial disease. Glycaemic control in the patients was assessed by the measurement of glycated haemoglobin.(AU)

Impaired vasodilatory reserve in diabetes with and without neuropathy - abstract

Several studies have shown that resting blood flow is increased in the diabetic neuropathic foot, It has been proposed that the mechanism involved is the loss of sympathetic tone which occurs when nervesto peripheral blood vessels are damaged resulting in blood vessels being constantly dilated. The extent to which further dilatation can be achieved when interrupted flow is resumed we termed vasodilatory reserve (VDR). This has not previously been investigated. We, therefore, attempted to assess the VDR in diabetes' blood vessels by measuring reactive hyperaemia at the ankle. The VDR was determined in 23 neuropathic (ND), and 16 non-neuropathic diabetic (D) patients and compared with 16 non-diabetic control subjects (C). Patients and controls were free from signs and symptoms of peripheral occlusive arterial disease. Glycaemic control are assessed by glycosylated haemoglobin levels. Ankle blood flow (Q) was measured by venous occlusion plethsmography. Reactive hyperaemia was induced by occlusion of the ankle at 200 mm Hg for 4 minutes. Blood flow was then measured at 1 minutes deflation of the occlusive cuff to 60 Hg. The VDR is expressed as the precentage change in blood flow from the resting value 1 minute after reactive hyperaemia. VDR was 14.49 percent, 20.8 percent and 114.75 percent in the ND, D and C groups respectively. Our present finding indicated and impaired vasodilatory reserve in the ankle of neuropathic and non-neuropathic diabetes pointing to their inability to adequately increase blood supply to the feet after interrupted flow(AU)