Importance of blood pressure variability in the assessment of cardiovascular risk and benefits of antihypertensive therapy

Although there is no doubt regarding the relationship between short-term blood pressure variability (BPV) and cardiovascular events in the hypertensive population, to date, the association between long-term BPV and target organ damage is unknown. Rothwell et al. recently published a post-hoc analysis of two large randomized trials, Anglo Scandinavian Cardiac Outcomes Trial Blood Pressure Lowering Arm (ASCOT-BLPA) and the Medical Research Council (MRC), aimed at demonstrating whether drug effects on short-term and long-term BPV explain the differences of antihypertensive treatment in stroke prevention. Analysis found that short-term and long-term BPV was lower in hypertensive patients treated with amlodipine with regards to atenolol. The amlodipine group showed a lower risk of stroke and coronary events with respect to subjects assigned to atenolol. Interestingly, the lower stroke risk detected in hypertensive patients treated with amlodipine was abolished after adjusting by within-individual BPV. Taking into account these findings, the authors concluded that the opposite effect of calcium channel blockers and β-blockers on BPV explains the disparity in the risk of stroke of patients under antihypertensive treatment. Therefore, to effectively prevent cerebrovascular events, blood pressure-lowering agents need both to reduce mean blood pressure and its short-term and long-term variability.