Impaired vascular reactivity in patients with chronic kidney disease.

Background: Patients with chronic kidney disease (CKD) show increased cardiovascular morbidity. We hypothesized that vascular properties which can be routinely evaluated noninvasively are related to different stages of CKD and their clinical and biochemical characteristics.

Methods: Arterial vascular properties were quantified by the reflective index using digital photoplethysmography in 260 patients with CKD. Patients were grouped according to estimated glomerular filtration rate (eGFR). Additional measurements were performed in 50 healthy control subjects.

Results: In patients with CKD stage 1 and 2 (n = 115; age 65 +/- 1 years) the reflective index was 30 +/- 1%, whereas in patients with CKD stage 3 and 4 (n = 60; age 72 +/- 1 years) the reflective index was 36 +/- 1%, and in patients with CKD stage 5 (n = 85; age 64 +/- 1 years) the reflective index was 36 +/- 1% (p < 0.01 by Kruskal-Wallis test) indicating increased arterial stiffness in advanced CKD. Arterial vascular reactivity was significantly impaired in patients with advanced stages of CKD (stage 1 and 2, 78 +/- 12%; stage 3 and 4, 32 +/- 12%; stage 5, 33 +/- 12%; p < 0.01). Univariate analysis showed a significant correlation of the reflective index and eGFR (Pearson r = -0.24; p < 0.0001). Multivariate regression analysis showed an independent association of the reflective index and eGFR (adjusted correlation coefficient, -0.24; p < 0.001).

Conclusion: The advanced stages of CKD are associated with increased vascular stiffness and impaired vascular reactivity and these changes are already present in CKD stage 3 and 4.