Treatment reduces central aortic blood pressure

Clinical update: Hypertension – The Conduit Artery Functional Endpoint (CAFE) study signalled a new area of inquiry concerning differentiating central blood pressure in the aorta from peripheral blood pressure in the arm.
It was always possible to measure central blood pressure using a catheter – an invasive technique. Nowadays, however, a device on the wrist can give continuous measurement of central blood pressure. Equipment such as the sphygmoCor measures and analyses the pulse wave in the wrist. After measuring the pressure of the radial artery, the system uses a computer algorithm to generate a pulse wave and measures pressures in the large arteries. Using a ‘transfer function’, it has been possible to get fairly robust estimates of central blood pressure.

There is evidence to suggest that this is the core of high blood pressure management. The kidneys and the vessels to the brain are very close to the aorta and microvascular damage in these organs is associated with central blood pressure.
Extensive future research in this area is expected. The 2005 CAFE study was a sub-study of central arterial blood pressure in the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT). CAFE identified that a group of hypertensive patients on a combination of an ACE inhibitors and calcium channel blockers had a significant reduction in central blood pressure. This was not seen with those on the combination of a diuretic and a beta blocker. “What the CAFE study really shows is that you can get similar pressures in the arm but very different pressures in the central arteries, depending on what the drugs do to the wave reflections in particular,” said lead investigator Dr Bryan Williams of the University of Leicester, UK.
The CAFE study revealed that the amlodipine antihypertensive treatment strategy, with perindopril added as required, results in significantly lower central arterial blood pressures than a treatment strategy with atenolol plus diuretic. The event rate for strokes and heart attacks was lower in the ACE/calcium channel blocker group. The amlodipine-based treatment resulted in a significant 16 per cent reduction in all cardiovascular events.
Arm blood pressure in the two groups had been reduced almost equally: there was only modest advantage with the ACE/calcium channel blocker when peripheral blood pressure was tested.