June 22, 2007 — Blood pressure (BP) targets in men and women with established coronary artery disease (CAD), or who are at high risk of developing CAD should be 130/80 mm Hg: lower than those specified in the Joint National Committee (JNC) 7th report of 140/90 mm Hg, a new American Heart Association Scientific Statement specifies. The BP target of 140/90 remains appropriate for general CAD prevention, the writing group, led by Dr Clive Rosendorff (Mount Sinai School of Medicine, New York, NY), says.
The JNC 7th report currently recommends that the lower target of 130/80 mm Hg be used in patients with diabetes or chronic kidney disease (CKD); the new statement suggests this group should be broadened. "When people walk into their doctors' offices with systolic pressures between 130 and 140, most primary care doctors and many cardiologists would believe that patient had normal blood pressure and wouldn't require additional treatment," Rosendorff told heartwire. "We have tried to show that in fact there is a great deal to be gained by treating those patients to lower levels."
The statement deals both with primary prevention patients — divided into "general" prevention or high CAD risk — as well as patients with pre-existing CAD in different forms: stable angina; unstable angina/non-ST elevation MI; ST-elevation MI; heart failure secondary to CAD. Patients in the high-risk category are defined as patients who also have diabetes, CKD, known CAD, a CAD-risk equivalent (carotid disease, peripheral artery disease, or abdominal aortic aneurysm), or a ten-year Framingham risk score ≥ 10%; these patients should all have their BP lowed to < 130/80 mm Hg, as would patients with pre-existing CAD. In patients with heart failure, physicians should consider a target even lower, the authors suggest, < 120/80 mm Hg, although blood pressure lowering should be slow, they caution.
Drug Therapy Recommendations
Authors of the statement also provide recommendations for drug therapy, according to CAD status. In keeping with recent European guidelines, beta-blockers are no longer recommended for blood pressure control in the primary prevention group.
"There have been lots of comparative clinical trails to show that for preventing both stroke and CAD complications, beta-blockers are inferior to newer classes of drugs like ACE inhibitors, angiotensin-receptor blockers, or calcium channel blockers, so we have dropped beta-blockers right out of the picture for prevention," Rosendorff explained. "However, once there is established, occlusive CAD, with symptoms like angina or acute MI, then beta-blockers come right back to center stage."
To heartwire, Rosendorff emphasized that this is the first time an AHA writing group has specifically tackled the topic of BP targets in the CAD population, despite the fact that the two conditions are pathophysiologically linked and constitute an "enormous public health issue." The new guidelines first appeared online last month; Rosendorff said he has already received some mixed feedback. "Some people think that 130/80 mm Hg is too low, and some think it's not low enough," he said. Overall, however, Rosendorff thinks many physicians are not yet aware of the recommendations, or do not appreciate the magnitude of the change.
"It doesn't sound like a lot — just 10 mm Hg — but in terms of the number of patients who are going to now require treatment if these guidelines are followed, it is huge," he said. "The impact is going to be that there will be many, many more people who will require antihypertensive medication, and of those already on antihypertensive medication, the management will need to be much more intensive or aggressive. But that's also going to translate into much better outcomes, much fewer heart attacks, and probably fewer strokes and fewer patients going into kidney failure."
Circulation. 2007;115;2761-2788.
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