Microalbuminuria is a late event in patients with hypertension: Do we need a lower threshold?

Abstract

Background: Microalbuminuria (MA) is a marker of vascular damage. However, many studies have observed an increased risk at lower levels of albuminuria than are currently used to define MA. Aim: To verify early cardiovascular changes occurring before MA in hypertensive patients. Materials and methods: One hundred and fifty hypertensive patients and 60 normotensive individuals were divided into normotensive individuals with normal left ventricular (LV) geometry (Group I), hypertensive patients with normal LV geometry (Group II), and hypertensive patients with abnormal LV geometry (Group III). The LV mass index, ambulatory arterial stiffness index, flow-mediated dilatation of the brachial artery, and intima-media thickness (IMT) of the common carotid were assessed. Urinary albumin/creatinine ratio was determined using a morning spot-urine sample. Results: Compared with Group I, ambulatory arterial stiffness index and IMT were significantly increased and flow-mediated dilatation was significantly decreased in Group II; however, MA did not differ between both groups. These changes were augmented when Group III was compared with Group II. MA significantly increased in Group III compared with Group II. Receiver operating characteristic analysis revealed that MA, with a cut-off value of 19.25 mg/g, predicted increased IMT, and abnormal LV geometry in a statistically significant manner. Conclusion: Many vascular changes, in the form of increased IMT, reduced vasodilator capacity, and increased arterial stiffness, preceded MA and any change in LV geometry. The results presented here strengthen the usefulness of adopting a lower cut-off to define MA.

Keywords

• Endothelium
• Hypertension
• Microalbuminuria