Abstract 3485: Endothelial Vasomotor Dysfunction in Brachial Artery Predicts Development of Early Renal Dysfunction in Hypertensive Patients
Endothelial function in renal vasculature plays an important role in the regulation of renal hemodynamics in normal and pathological states. Endothelial dysfunction occurs in systemic vasculature of hypertensive (HT) patients, and there may be a relationship between endothelial function in brachial artery and renal vasculature. This study examined whether endothelial vasomotor dysfunction in brachial artery predicts early renal dysfunction in HT patients. Flow-mediated endothelium-dependent dilation (FMD, % increase in diameter from baseline) in brachial artery was measured in 546 consecutive HT patients (BP ≥ 140/90 mmHg or the use of anti-hypertensive medication). Patients with advanced renal failure (glomerular filtration rate [GFR] < 50 ml/min/1.73 m2) were excluded. A subgroup of 306 HT patients with normal renal function at enrollment (normo-albuminuria [< 30 mg/day] and normal serum creatinine levels [<1.0 mg/dL]) were prospectively followed for 1.5 years. The end point was the occurrence of either serum creatinine levels > 1.2 mg/dL or microalbuminuria (> 30 mg/day). Patients with impaired FMD (< 5.1%, 50th percentile of the distribution in total HT patients) had higher levels of urine albumin (9.3 ± 0.3 vs. 7.5 ± 0.3 mg/day, p < 0.05) and serum creatinine (0.72 ± 0.1 vs. 0.68 ± 0.1 mg/dL, p < 0.05), and lower GFR (77.8 ± 3.1 vs. 97.7 ± 2.2 ml/min/1.73 m2, p < 0.05) at enrollment than patients with preserved FMD (≥ 5.1%). During follow-up, 37 (24%) patients with impaired FMD had an end point (an increase in creatinine levels in 34 patients, an increase in albuminuria in 23), while 15 (9.8%) patients with preserved FMD had an end point (an increase in creatinine levels in 9, albuminuria in 6) (p < 0.01). Using multivariate logistic analysis, impaired FMD was the strongest predictor of the occurrence of either an increase in serum creatinine levels or microalbuminuria (OR; 2.9, 95%CI; 1.5 − 5.6, p < 0.01) among all covariates, including diabetes, age, and use of anti-hypertensive drug. Endothelial vasomotor dysfunction in brachial artery is an independent predictor of the development of early renal dysfunction in HT patients. The measurement of FMD is useful for risk stratification of future renal dysfunction in HT patients.