NEW YORK (Reuters Health) – Amlodipine decreases central systolic blood pressure more effectively when combined with valsartan than with atenolol, French researchers reported online April 19th in Hypertension.

They point out that the beta blocker atenolol is known to be less effective at reducing central aortic systolic blood pressure compared to angiotensin converting-enzyme inhibitors, angiotensin receptor blockers, and calcium channel blockers.

But “an important unanswered question is whether the lesser effect of atenolol on central aortic blood pressure is dampened or reversed when combined with calcium channel blockers or whether it remains significant despite associated vasodilatation,” according to lead author Dr. Pierre Boutouyrie from Universite Paris-Descartes and colleagues.

In the randomized EXPLORER trial, the researchers addressed this question, randomizing 393 patients with resistant hypertension to 6 months of treatment with amlodipine plus either valsartan or atenolol.

At 24 weeks, the two groups had similar decreases in brachial blood pressure. Rates of blood pressure control were also similar at 8 weeks (47% in the valsartan group and 43% in the atenolol group) and 24 weeks (56% and 59%, respectively).

The two groups also had similar decreases in aortic diastolic blood pressure – but aortic systolic blood pressure was 3.95 mmHg lower in the amlodipine-valsartan group (p = 0.013).

In addition, aortic pulse pressure was 3.74 mmHg lower with valsartan (p < 0.001). The augmentation index decreased with the valsartan combination and increased with the atenolol combination, resulting in a significant difference between the groups of 6.5% (P<0.001). The between-treatment differences at 24 weeks persisted after adjustment to baseline values, changes in heart rate, and other significant covariates. “The present study strongly suggests that, even when combined with a calcium channel blocker, atenolol might not reduce central blood pressure enough to effectively protect against cardiovascular events,” the authors conclude. They add, “An outcome trial is required to determine whether the differences in central blood pressure between the treatment groups translate into clinical benefit.” Reference:
http://hyper.ahajournals.org/cgi/content/abstract/HYPERTENSIONAHA.109.148999v1
Hypertension 2010.