Agents blocking the renin-angiotensin-aldosterone system are frequently used in patients with end-stage renal disease, but whether they exert beneficial cardiovascular effects is unclear. Here the long-term effects of the angiotensin II receptor blocker, irbesartan, were studied in hemodialysis patients in a double-blind randomized placebo-controlled 1-year intervention trial using a predefined systolic blood pressure target of 140 mm Hg (SAFIR study). Each group of 41 patients did not differ in terms of age, blood pressure, comorbidity, antihypertensive treatment, dialysis parameters, and residual renal function. Brachial blood pressure decreased significantly in both groups, but there was no significant difference between placebo and irbesartan. Use of additional antihypertensive medication, ultrafiltration volume, and dialysis dosage were not different. Intermediate cardiovascular end points such as central aortic blood pressure, carotid-femoral pulse wave velocity, left ventricular mass index, N-terminal brain natriuretic prohormone, heart rate variability, and plasma catecholamines were not significantly affected by irbesartan treatment. Changes in systolic blood pressure during the study period significantly correlated with changes in both left ventricular mass and arterial stiffness. Thus, significant effects of irbesartan on intermediate cardiovascular end points beyond blood pressure reduction were absent in hemodialysis patients.

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Background Arterial calcification is associated with cardiovascular mortality in dialysis patients. Active matrix Gla-protein (MGP) is a vitamin K-dependent inhibitor of arterial calcification. Elevated plasma concentrations of inactive MGP, i.e. dephosphorylated-uncarboxylated MGP (dp-ucMGP), is prevalent in dialysis patients. MGP inactivity might contribute to arterial calcification. We investigated if vitamin K supplementation had an effect on arterial calcification in chronic dialysis patients. Methods In a two-year double-blind, placebo-controlled intervention trial, 48 dialysis patients were randomised to vitamin K (menaquinone-7 (MK-7), 360 µg daily), or placebo. MK-7 in serum and dp-ucMGP in plasma were used to assess vitamin K status. Carotid-femoral pulse wave velocity (cfPWV) and scores of coronary arterial calcification (CAC) and abdominal aorta calcification (AAC) were used to assess arterial calcification. Results Thirty-seven participants completed year one, 21 completed year two. At year two, serum MK-7 was 40-fold higher, and plasma dp-ucMGP 40% lower after vitamin K supplementation compared with placebo (mean dp-ucMGP difference: -1380 pmol/L (95% CI: -2029;-730)). There was no significant effect of vitamin K supplementation on cfPWV (mean difference at year two: 1.2 m/s (95% CI: -0.1; 2.4)). CAC Agatston score increased significantly in vitamin K supplemented participants, but not significantly different from placebo (mean difference at year two: 664 (95% CI: -554; 1881)). AAC scores increased in both groups, significantly so within the placebo group at year 1, but with no significant between-group differences. Conclusion Vitamin K supplementation improved vitamin K status, but did not hinder or modify the progression of arterial calcification in dialysis patients.