The benefits of blood-pressure lowering treatment based on Pfizer’s Norvasc (amlodipine) may be underestimated, while the benefits of atenolol-based treatment may be overestimated, according to results of the CAFÉ study, presented for the first time on 13 November at the 2005 Scientific Sessions of the American Heart Association in Dallas.
CAFÉ included more than 2,000 patients from ASCOT, which was published earlier this year and demonstrated better outcomes in patients receiving amlodipine-based treatment compared to atenolol-based treatment. By using the non-invasive SphygmoCor system, CAFÉ investigators showed that amlodipine-based treatment is much better at lowering blood pressure around the heart than atenolol-based treatment.
This finding suggests that the usual method of measuring blood pressure at the upper arm (brachial pressure) underestimates the efficacy of vasodilating drugs such as amlodipine and overestimates the efficacy of vasoconstricting drugs such as atenolol. The results also go a long way to explaining the results of ASCOT and will no doubt further consolidate amlodipine’s position in the market, but CAFÉ has other important implications.
CAFÉ is the first large clinical outcomes trial to demonstrate that, despite a similar impact on brachial pressure, antihypertensive drugs have profoundly different effects on central blood pressures. By providing a clear physiological mechanism for the results of ASCOT, CAFÉ will also undoubtedly add to pressures to revise national and international guidelines and further discourage blood pressure lowering with atenolol except in high-risk patients with diagnosed cardiovascular disease.
Brachial pressures can still be used to guide treatment in clinical practice, but CAFÉ is likely to encourage the use of central pressure measurement in clinical trials, and may in future help to guide the develop of antihypertensives that more effectively target central blood pressure.