Amlodipine-valsartan combination decreases central systolic blood pressure more effectively than the amlodipine-atenolol combination: the EXPLOR study

Abstract

The beta-blocker atenolol is less effective than angiotensin-receptor blockers and calcium-channel blockers for reducing central blood pressure (BP). The trial was designed to determine whether the advantages of angiotensin-receptor blockers over atenolol remained significant when both were combined with the calcium-channel blocker amlodipine. A prospective, randomized, blinded endpoint (PROBE design) parallel group, multicenter trial including 393 patients with essential hypertension resistant to 4 weeks of 5 mg of amlodipine was set out. Central systolic BP, augmentation index (AIx; either rough or adjusted on heart rate), and carotid-to-femoral pulse wave velocity were measured with applanation tonometry (SphygmoCor) at inclusion and after 8 and 24 weeks of active treatment with an amlodipine-valsartan combination (5/80 mg and then 10/160 mg) or an amlodipine-atenolol combination (5/50 mg and then 10/100 mg). From baseline to week 24, central systolic BP decreased significantly more in the amlodipine-valsartan group (-13.70+/-1.15 mm Hg; P<0.0001) than in the amlodipine-atenolol group (-9.70+/-1.10 mm Hg; P<0.0001; difference: -4.00 mm Hg [95% CI: -7.10 to -0.90]; P=0.013), despite similar changes in brachial systolic BP. The difference in rough AIx reduction was -6.5% (95% CI: -8.3 to -4.7; P<0.0001) in favor of amlodipine-valsartan. AIx adjusted on heart rate was significantly reduced in favor of amlodipine-valsartan (-2.8% [95% CI: -4.92 to -0.68]; P<0.01). Heart rate decreased significantly more with amlodipine-atenolol (difference: -11 bpm [95% CI: -14 to -8 bpm]; P<0.001). Pulse wave velocity decreased by 0.95 m/s in both groups with no significant difference. Differences in central systolic BP and rough AIx remained significant after adjustment to the changes in heart rate. The amlodipine-valsartan combination decreased central (systolic and pulse) pressure and AIx more than the amlodipine-atenolol combination.