Vascular Assessment in the Neuropathic Diabetic Foot
ABSTRACT Diabetic foot infections, a common source of morbidity and mortality, often have been related to vasculopathy and neuropathy in its etiopathogenesis, especially in the elderly person with diabetes. However, blood flow in the neuropathic diabetic foot has not been evaluated extensively, and there is evidence of abnormal blood flow patterns in the neuropathic diabetic foot unrelated to ischemia. The authors studied young persons with diabetes, with varying degrees of neuropathy, to assess the extent of vasculopathy in their lower limbs. Twelve young persons with insulin-dependent (Type I) diabetes (mean age, 36.1 +/- 1.975 years) and peripheral neuropathy, all of whom had previous surgery for diabetic foot infections, were identified. Confirmatory evidence of neuropathy was made using electromyographic studies and clinical tests that showed severe peripheral neuropathy. The results of vascular assessment of both lower limbs did not reveal any change in the pulse wave velocities from the popliteal to the digital vessels of the big toe as compared with correspondingly matched controls. There also was no significant stenosis in any of the vessels studied as far as the level of the dorsalis pedis and posterior tibial vessels. The normal triphasic pattern of arterial blood flow was lost. A monophasic pattern was present in all patients with prolonged diastolic flow at the level of the dorsalis pedis and posterior tibial arteries and distally. The pulsatility index was 3.14 +/- 0.81 as compared with 9.85 +/- 4.2. Mean toe pressures in the patient with diabetes was 64.17 +/- 20.87 mm Hg as compared with 98.23 +/- 10.12 mm Hg in controls. A linear correlation of decreasing toe pressures with increasing severity of neuropathy was seen (R = 0.7). The data suggest that changes exist in the blood flow patterns in young patients with diabetes and neuropathy, even in the absence of lower limb ischemia.
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ABSTRACT: We studied the relationship between vasoconstrictor changes in foot arteries (pedal, metatarsal, and digital arteries) and autonomic neuropathy in diabetic patients to estimate the degrees of sympathetic dysfunction. Sixty-two patients and nineteen age-matched control subjects were studied. The resistance index (RI) and pulsatility index (PI) were measured as vascular hemodynamic parameters using Doppler sonography, and the increases in these hemodynamic parameters (%RI and %PI) from rest to a deep breath were measured as indexes of the degrees of sympathetic vasoconstrictor function. Cardiovascular autonomic function tests (AFTs) were performed and the score was compared to %RI and %PI values obtained. Of the 62 diabetic patients, 51 had various degrees of autonomic neuropathy. Both %RI and %PI in the diabetic patients were significantly less than those in the control subjects for all foot arteries tested (all P < 0.001). There were strongly inverse correlations between the %RI and %PI of foot arteries and the AFT score (r = -0.556 to -0.846, P < 0.0001). The %RI of the digital artery was the most strongly correlated with AFT score (r = -0.846, P < 0.0001) among foot arteries tested. The abnormality of sympathetic vasoconstriction was detectable in the majority of the diabetic patients with the early phase of autonomic neuropathy (%RI: 89.5%; %PI: 94.5%). We conclude that the %RI of the digital artery is a useful and reliable sympathetic function test of early phase in diabetic patients.Diabetes Care 09/1998; 21(9):1495-501. DOI:10.2337/diacare.21.9.1495 · 8.57 Impact Factor
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ABSTRACT: on-invasive laboratory tests are commonly employed in the assessment of lower limb perfusion. The accuracy of non-invasive assessments in diabetes remains a concern. We evaluated the more commonly used methods with particular reference to diabetic foot disease. A literature review and clinical evaluation of tests for macrovascular disease, including hand held Doppler, blood pressure measurement and indices, Doppler waveform analysis, colour duplex imaging and plethysmography was performed. Tests reflecting tissue perfusion, including infrared detectors, transcutaneous oxygen tension, laser Doppler, capillaroscopy and skin temperature were also reviewed. Non-invasive laboratory tests reduce the requirement for invasive investigations and their inherent risks. More traditional non-invasive methods are being replaced by evolving techniques employing ultrasound technology. Arterial calcification and peripheral neuropathy associated with diabetes can potentially reduce the reliability of these methods. Distal limb and tissue perfusion assessments are more likely to reflect local vascularity. Tissue perfusion indicators are generally slow and vulnerable to environmental influences, thus limiting their clinical use. Nevertheless, non-invasive tests are an important adjunct to the clinical evaluation of diabetic foot disease. However, diabetes potentially reduces their reliability and the results require careful interpretation. Distal perfusion tests have potential advantages over macrovascular assessments. The influence of diabetes on non-invasive tests needs further evaluation.The British Journal of Diabetes & Vascular Disease 03/2005; 5(2):64-70. DOI:10.1177/14746514050050020301
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ABSTRACT: Foot-related disease is the most common cause for hospital admission among the diabetic population. Lower-limb peripheral arterial occlusive disease (PAOD) is a major risk factor in diabetic foot disease. Screening for PAOD commonly includes foot pulses and the ankle-brachial pressure index (ABPI) and/or the toe-brachial pressure index (TBI), but concerns persist regarding their accuracy. We evaluated the efficacy of several commonly used screening methods in different subject populations. We studied 130 limbs in 68 individuals with no critical ischemia over 8 months. Limbs were grouped on the basis of the presence or absence of diabetes, clinically detectable peripheral neuropathy, and PAOD identified on color duplex imaging. Comparative analyses of foot pulses, the ABPI, the TBI, and distal Doppler waveform analysis were performed. Foot pulses, the TBI, and qualitative waveform analyses were highly sensitive screening methods in individuals with and without diabetes. However, detectable peripheral neuropathy was associated with a reduced sensitivity and poor specificity of foot pulses, a reduction in sensitivity of the ABPI (71 to 38%), and a reduction in specificity of the TBI (81 to 61%) and qualitative waveform analysis (96 to 66%). Quantitative analysis failed to detect disease with severely damped and low-intensity signals. Screening tools that are effective in screening for lower-limb PAOD in the nondiabetic population are less efficacious in diabetes, particularly in the presence of detectable peripheral neuropathy. Qualitative waveform analysis and the TBI were demonstrated to be more effective screening methods than the ABPI and foot pulses particularly in high-risk limbs with detectable peripheral neuropathy.Diabetes Care 10/2005; 28(9):2206-10. DOI:10.2337/diacare.28.9.2206 · 8.57 Impact Factor