Symmetrical Ambulatory Arterial Stiffness Index: Relationship with Serum Cystatin C Levels

Abstract

Objective: Increased central arterial stiffening is the consequence of many disease states such as diabetes, atherosclerosis, and chronic renal disease. Symmetrical Ambulatory Arterial Stiffness Index (Sym-AASI) may provide a simple clinical approach to evaluate arterial stiffness. This study has tried to evaluate the relationship of Sym-AASI with cystatin C levels. Design and methods: The sample subjects were 53 males and 34 females (mean age = 59.3 ± 13.5 years). Kidney function was evaluated by measuring serum cystatin C and estimated glomerular filtration rate (eGFR). The ambulatory BP was measured noninvasively for 24 h. Results: Patients in the highest quartile showed an older age ( p < 0.001) and worse eGFR (p < 0.001). Pulse pressure (PP) increased as cystatin C was higher. Mean Sym-AASI showed an increase from the first to the last cystatin C quartile. Correlation test showed a significant relationship of Sym-AASI with age (r = 0.573), serum creatinine (r = 0.237), eGFR (-0.323), cystatin C (r = 0.427), systolic blood pressure (r = 0.525), and PP (r = 0.647). Multivariate regression analysis showed that age, cystatin C, nocturnal systolic blood pressure reduction, and nocturnal diastolic blood pressure fall were independently related to Sym-AASI. There was not any independent association between eGFR and Sym-AASI or between cystatin C and PP. Conclusions: Increased Sym-AASI seems to be independently associated with serum cystatin C levels. Sym-AASI seems to be better than PP to detect changes in the arterial wall. This could be a simple and easy method to evaluate arterial stiffness in hypertensive patients without needing more complex devices.

What is the Ambulatory Stiffness Index and What Is Its Role in Patients With Lacunar Infarcts?

“…It was found to correlate with pulse pressure (PP) and pulse wave velocity (PWV) and was thus presumed to be another marker of large artery stiffness, which is readily available from ABP. Moreover, one of the most attractive features of AASI was that it was found to be a significant predictor of stroke, cardiovascular disease, renal dysfunction, hypertensive target organ damage, and all‐cause mortality, and, in many of these studies, independently from BP or PP. This independence of BP (or PP) brought about investigations of its possible arterial properties.…”

“…Gavish and colleagues found that some of the problems associated with AASI (for instance its dependence on nocturnal BP decline) can be improved when using a more advanced form of regression of systolic and diastolic BP, the so‐called symmetric regression, which, in this context, provides a slope between that of diastolic on systolic and that of systolic on diastolic BP regression lines. This symmetric AASI (sAASI) has been found to better represent arterial stiffness in patients with HIV, to be associated with cystatin C as a measure of renal dysfunction, and to be associated with estimated glomerular filtration rate and microalbuminureia . Moreover, Gavish and colleagues found that their regression slope was both a mathematic and empiric ratio of the variability of systolic BP over that of diastolic BP, ie, the BP variability ratio (BPVR).…”