Introduction on Hypertension in Chronic Kidney Disease – Role of Arterial Calcification and Impact on Treatment
Chronic kidney disease (CKD) is characterised by progressive nephron loss leading to increased intraglomerular pressure, glomerular permeability, proteinuria and systemic hypertension. The prevalence of CKD defined as estimated glomerular filtration rate (eGFR) of <60 mL/min per 1.73 m2 ranges from 2 to 12 % in Europe and in the US.1,2 CKD is an independent risk factor for the development of cardiovascular diseases (CVDs), showing a graded risk of cardiovascular events as eGFR declines, with a sharp rise in events as eGFR falls <45 mL/min per 1.73 m2.3 Hypertension prevalence increases as renal function declines and may be present in more than 80 % of patients with stage 4 to 5 CKD.4 Hypertension contributes to progression of kidney disease as well as to cardiovascular (CV) events such as myocardial infarction, congestive heart failure and stroke. In Western countries, approximately 20–30 % of incident end-stage renal disease (ESRD) cases are attributed to hypertension.1,2 One characteristic of hypertension is the remodelling of the arterial wall in response to the increase in blood pressure (BP). Moreover, with time, significant modifications in extracellular matrix composition and in vascular cell phenotype occur in the vasculature.5 Vascular tissue remodelling associated with hypertension, might actually create an environment for calcium deposition within the arteries.6 This phenomenon is particularly important in CKD patients. Indeed, in CKD, vascular calcifications are clearly associated with a higher CV morbidity and mortality.3 Although calcification of large arteries and BP increase with ageing, only a few studies specifically investigated the interaction between these two factors as aggravating mechanisms of hypertension and CV events, and as promoters of a more rapid decline of renal function in CKD. In this review, we will focus on accelerated vascular calcification and its association with CKD and hypertension.