Vascular calcification and increased mortality in dialysis patients: is the baroreflex sensitivity the answer?

Sir,

In their interesting paper, Chesterton et al. [1] gave evidence for a possible link between vascular calcification, increased arterial stiffness (determined by time to shoulder, TTS) and impaired autonomic function (reduction in baroreflex sensitivity, BRS). This study adds new insights in the currently ongoing discussion dealing with vascular calcification and increased mortality in dialysis patients [2]. Impaired autonomic control of blood pressure due to vascular calcification could not only be a possible explanation for dialysis-induced hypotension but also a significant risk factor for the excessive cardiovascular mortality found in the dialysis population. Although Chesterton et al. [1] showed a significant association between vascular calcification and BRS (5.67±0.76 vs 3.43±0.38 ms/mmHg in the group with and without calcification) as well as a significant but low correlation between TTS and BRS (r = 0.41), they failed to show a significant association between vascular calcification and increased arterial stiffness. This raises the question whether other variables not included in their analysis but obviously present in their study population are involved in reduced BRS, elevated arterial stiffness and vascular calcification. These variables include diabetes mellitus and smoking, which have been shown to impair BRS, enhance vascular calcification and lead to arterial stiffening [3,4]. Furthermore, the use of different antihypertensive drugs, such as α- and β-blockers or angiotensin-converting enzyme inhibitors, can significantly influence autonomic control and therefore alter BRS independently of arterial function and structure [5]. For that reason, information on the antihypertensive drugs used in the study population should be given by the authors. The link between alterations in arterial structure, arterial function and autonomic regulation might offer new pathophysiological insights, but larger studies controlling for the above mentioned factors have to be done to prove this relationship.

Conflict of interest statement. None declared.