Symmetrical ambulatory arterial stiffness index: relationship with microalbuminuria and renal function

The aim of this study was to investigate the arterial stiffness parameters derived from the proposed linear relationship between SBP and DBP obtained by ABPM, regarding its relationships with two markers of renal disease, microalbuminuria and renal function.

One hundred and sixty six patients were studied: 73 males and 93 females mean age 55.2+/-15.5 years. 36.2% were receiving antihypertensive drug treatment. Microalbuminuria was measured in 24-h urine collection as well as albumin to creatinine ratio (ACR) in first morning urine. The ambulatory BP was measured non-invasively for 24 h by the Spacelab devices.

Correlation test showed a significant relationship of Sym-AASI with age (p<0.001), serum creatinine (p=0.038), creatinine clearance (-0.423, p<0.001) and GFR (-0.263, p<0.001). On the other hand AASI was also correlated with age (p<0.001) and creatinine clearance (p=0.012), but not with the other parameters studied. 24-h albumin excretion rate was not correlated with Sym-AASI or AASI. Contrariwise, the albumin to creatinine ratio was correlated with Sym-AASI (p=0.013). As expected, AASI and Sym-AASI increase as severity of renal diseases grows. The patients in the highest quartile of Sym-AASI distribution showed an older age (p<0.001) and worse parameters of renal function (GFR, p<0.001; and creatinine clearance, p<0.008).

Sym-AASI, an improved method for detecting arterial stiffness, seems to get an independent relationship with these parameters of renal disease which could not be detected with AASI.