Ambulatory blood pressure and cardiovascular events in chronic kidney disease

Abstract

Hypertension is an important risk factor for adverse cardiovascular and renal outcomes, particularly in patients with chronic kidney disease (CKD). This review compares blood pressure (BP) measurements obtained in the clinic with those obtained outside the clinic to predict cardiovascular and renal injury and outcomes. Data are accumulating that suggest that ambulatory BP monitoring is a superior prognostic marker compared with BP values obtained in the clinic. The use of ambulatory BP monitoring can detect white-coat hypertension and masked hypertension, which results in less misclassification of BPs. Ambulatory BP monitoring is a marker of cardiovascular end points in CKD. Nondipping is associated with proteinuria and lower glomerular filtration rate. Although nondipping is associated with more end-stage renal disease and cardiovascular events, adjustment for other risk factors removes the prognostic significance of nondipping. For patients with CKD who are not on dialysis, 24-hour ambulatory BPs of less than 125/75 mm Hg, daytime ambulatory BP of less than 130/85 mm Hg, and nighttime ambulatory BPs of less than 110/70 mm Hg appear to be reasonable goal BP targets. In the management of hypertension in patients with CKD, control of hypertension is important. Ambulatory BP monitoring may be useful to assign more aggressive treatment to patients with masked hypertension and withdraw antihypertensive therapy in patients with white-coat hypertension. Ambulatory BP monitoring can refine cardiovascular and renal risk assessment in all stages of CKD. The independent prognostic role of nondipping is unclear.

Figure 1. Cumulative risk of end-stage renal disease (ESRD) according to level of systolic ambulatory blood pressure (BP)

24-hour ambulatory systolic blood pressures were divided into three categories, <130 mm Hg, 130-<160 mm Hg and 160 mm Hg or more, reflecting nationally recommended levels of control, and two degrees of poor control. 3/76 (4%) patients in the well controlled category had ESRD, 23/88 (26%) patients in 130-<160 mm Hg had ESRD and 8/11 (73%) in the 160 mm Hg or more category had ESRD (p<0.0001 by log-rank test). (From Agarwal R, Andersen MJ: Kidney Int. 2006, 69:1175-1180. with permission)