Department of Internal Medicine, University of Pisa, Via Roma 67, 56100 Pisa, Italy.
Diabetologia. 2011 Sep;54(9):2430-9. doi: 10.1007/s00125-011-2148-y. Epub 2011 Apr 16.
AIM/HYPOTHESIS: Renal resistive index is a useful measure for quantifying alterations in renal blood flow. In the present study we evaluated resistive index at baseline and after vasodilation induced by nitroglycerine in normoalbuminuric patients with type 2 diabetes or essential hypertension, relating the values to indices of systemic vascular dysfunction.
Newly diagnosed treatment-naïve type 2 diabetic (n = 32) and hypertensive patients (n = 49) were compared with 27 age- and sex-matched healthy controls. Renal resistive index was obtained by duplex ultrasound at baseline and after 25 μg sublingual nitroglycerine. Endothelium-dependent (flow-mediated dilation) and -independent (response to nitroglycerine) vasodilation in the brachial artery was assessed by computerised edge detection system. Carotid-femoral pulse-wave velocity and augmentation index were assessed by applanation tonometry. Nitrotyrosine levels, an index of oxidative stress, were also measured.
Resistive index was higher in diabetic than in hypertensive patients and controls (p < 0.001), while changes in resistive index induced by nitroglycerine were lower in hypertensive patients compared with controls (p < 0.01), and were further reduced in type 2 diabetic patients. Hypertensive and diabetic patients showed significantly increased arterial stiffness, nitrotyrosine levels and reduced endothelial function than controls (p < 0.05). Changes in resistive index induced by nitroglycerine were independently related to serum glucose, reactive hyperaemia and aortic pulse-wave velocity in the overall population.
CONCLUSIONS/INTERPRETATION: These results support the dynamic evaluation of renal resistive index as an early detector of renal vascular alterations in the presence of type 2 diabetes and hypertension, even before the onset of microalbuminuria.
目的/假设：肾血管阻力指数是衡量肾血流变化的有用指标。本研究评估了 2 型糖尿病或原发性高血压患者在基础状态和舌下含服硝酸甘油扩张血管后的肾血管阻力指数，并将其与系统性血管功能障碍的指标相关联。
新诊断的未接受治疗的 2 型糖尿病（n = 32）和高血压患者（n = 49）与 27 名年龄和性别匹配的健康对照者进行比较。通过双功能超声在基础状态和舌下含服 25 μg 硝酸甘油后获得肾血管阻力指数。通过计算机边缘检测系统评估肱动脉内皮依赖性（血流介导的扩张）和非依赖性（对硝酸甘油的反应）血管扩张。通过平板测压法评估颈动脉-股动脉脉搏波速度和增强指数。还测量了氧化应激的指标——硝基酪氨酸水平。
与高血压患者和对照组相比，糖尿病患者的肾血管阻力指数更高（p < 0.001），而硝酸甘油诱导的肾血管阻力指数变化在高血压患者中低于对照组（p < 0.01），且在 2 型糖尿病患者中进一步降低。高血压和糖尿病患者的动脉僵硬度、硝基酪氨酸水平和内皮功能均显著高于对照组（p < 0.05）。硝酸甘油诱导的肾血管阻力指数变化与总体人群的血清葡萄糖、反应性充血和主动脉脉搏波速度独立相关。
结论/解释：这些结果支持动态评估肾血管阻力指数作为 2 型糖尿病和高血压患者肾血管改变的早期检测指标，甚至在微量白蛋白尿出现之前。
