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New AHA Statement Sets Lower BP Targets for High-Risk and Established CAD Patients CME/CE
News Author: Shelley Wood
CME Author: Charles Vega, MD
from Heartwire — a professional news service of WebMD
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.
The complete contents of Heartwire, a professional news service of WebMD, can be found at www.theheart.org, a Web site for cardiovascular healthcare professionals.
Clinical Context
Hypertension is one of the most common diseases in the United States. Using the cutoff of 140/90 mm Hg or greater to define hypertension, nearly one quarter of adults can be diagnosed with hypertension. Another one fourth of adults have prehypertension, as defined by a systolic BP between 120 and 139 mm Hg and a diastolic BP between 80 and 89 mm Hg.
Systolic BP rises steadily with age, whereas diastolic BP tends to fall among adults older than 50 years. The roles of systolic and diastolic BP in predicting ischemic heart disease also change with age, with diastolic BP presenting a more severe risk in adults younger than 50 years and systolic BP being more significant among adults older than 60 years.
Systolic BP reduction of 10 mm Hg during middle age can reduce the risk for cardiovascular death by approximately 50%. The current recommendations focus on the treatment of hypertension among patients at risk for ischemic heart disease.
Study Highlights
* For general prevention of ischemic heart disease, the BP should be lowered to less than 140/90 mm Hg. Among patients with a 10-year Framingham risk score for cardiovascular disease exceeding 10%, diabetes, CKD, or known CAD, the goal BP should be less than 130/80 mm Hg. The authors advocate a BP goal of less than 120/80 mm Hg among patients with left-sided ventricular dysfunction.
* Whereas the theory that an excessive drop in diastolic BP can promote worse cardiovascular outcomes is controversial and only partly supported by clinical studies, the authors recommend reducing the diastolic BP slowly. Caution is advised when the diastolic BP falls below 60 mm Hg among patients older than 60 years and those with diabetes.
* Reducing BP to goal levels is more important than the choice of antihypertensive drug in reducing cardiovascular risk. First-line therapy may include a thiazide diuretic, angiotensin-converting enzyme (ACE) inhibitor (or angiotensin receptor blocker [ARB]), or calcium channel blocker. If the BP goal requires a reduction of more than 20/10 mm Hg to reach goal, clinicians should consider using 2 medications to lower BP initiated simultaneously.
* Treatment for patients with hypertension and chronic stable angina should include a β-blocker if there is a history of prior myocardial infarction. Nondihydropyridine calcium channel blockers may be used if patients are intolerant of β-blockers but should not be used in the setting of left-sided ventricular dysfunction.
* β-Blockers are the treatment of choice for patients hospitalized with coronary syndromes. These patients should receive ACE inhibitors or ARBs if there is evidence of anterior myocardial infarction, persistent hypertension, or heart failure or if the patient has diabetes.
* Aldosterone antagonists may be considered for patients with left-sided ventricular dysfunction, but these medications should be avoided if the serum creatinine level meets or exceeds 2.5 mg/dL in men or 2.0 mg/dL in women. Aldosterone antagonists are also not appropriate for patients with serum potassium levels of 5 mEq/L or greater.
* Concomitant use of ACE inhibitors and ARBs should be avoided in the immediate period following ST-elevation myocardial infarction, but it is permissible to use medications from these different classes together among patients with hypertension and heart failure.
* α-Adrenergic antagonists such as doxazosin should be used among patients with hypertension and heart failure only when all other medications have been used to maximum effect.
Pearls for Practice
* Approximately one quarter of US adults have prehypertension and one quarter have hypertension, respectively. Systolic BP increases gradually as adults grow older, and it is a stronger predictor of ischemic heart disease than diastolic BP among adults older than 60 years.
* The current guidelines recommend that initial treatment of hypertension among patients without known heart disease or diabetes may include ACE inhibitors, ARBs, calcium channel blockers, or thiazide diuretics.
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