Updated secondary prevention guidelines pull together the latest data from clinical trials to advocate more aggressive management of patients with coronary heart disease.
The American Heart Association/American College of Cardiology Guidelines for Secondary Prevention for Patients with Coronary and Other Atherosclerotic Vascular Disease: 2006 Update assembles evolving evidence from a number of trials involving the management of key risk factors.
“Physicians may have followed the low-density lipid story but they may not be aware of the recommendations for waist circumference or have a good idea about what to do about ACE inhibitors. This puts it all together, hopefully in a useable manner,” said Dr. Sidney C. Smith Jr., chairman of the ACC/AHA writing group.
Here's a look at the new guidelines, which advise the following changes to pharmacologic management:
▸ Lipid management. The goal of less than 100 mg/dL for LDL cholesterol is unchanged, but the guideline adds that further reduction to levels less than 70 mg/dL is reasonable. If triglyceride levels are 200–499 mg/dL, non-HDL cholesterol should be less than 130 mg/dL; further reduction below 100 mg/dL is reasonable.
The lipid management guidelines reflect recommendations made in 2004 by the National Cholesterol Education Program (NCEP) Adult Treatment Panel, which advised a target LDL level of less than 100 mg/dL and offered an optional target of 70 mg/dL in patients at very high risk. More recent study results, such as those from the Treating to New Targets (TNT) and the Incremental Decrease in End Points Through Aggressive Lipid Lowering (IDEAL) studies, show that aggressive lipid-lowering therapy provides significant clinical benefit in patients who have stable coronary heart disease.
“These guidelines reinforce the fact that all patients [with coronary heart disease] should have LDL of less than 100 mg/dL and provide a reasonable target of 70 mg/dL,” said Dr. Smith, a professor of medicine and director of the center for cardiovascular science and medicine at the University of North Carolina at Chapel Hill.
▸ Antiplatelet and anticoagulant therapy. Aspirin therapy has been reduced to 75–162 mg/day, down from 75–325 mg/day in all patients, unless contraindicated. The lowering of the aspirin dose for chronic therapy was based largely on antiplatelet trials, which showed that the benefits of aspirin therapy are the same for lower dose regimens (75–80 mg) as for the adult dose (325 mg) but that the risk of bleeding was considerably less for the lower dose, said Dr. Smith.
Following acute coronary syndrome or percutaneous coronary intervention with stent placement, start and continue 75 mg/day of clopidogrel in combination with aspirin for up to 12 months. Therapy for stent recipients, for which the aspirin dosage is 325 mg/day, should last at least 1 month in patients who have received bare-metal stents, at least 3 months in those who have received sirolimus-eluting stents, and at least 6 months in those who have received paclitaxel-eluting stents.
▸ Renin-angiotensin-aldosterone system blockers. The guidance for these agents has expanded considerably. ACE inhibitors are recommended for indefinite use in all patients with a left ventricular ejection fraction (LVEF) of 40% or less and in those with hypertension, diabetes, or chronic kidney disease unless contraindicated. The use of ACE inhibitors should be considered in all patients.
Angiotensin receptor blockers (ARBs) should be used in patients who are intolerant of ACE inhibitors and have heart failure or have had an MI with a LVEF of 40% or less. The use of ARBs should be considered in other patients who are intolerant of ACE inhibitors. In patients with systolic heart failure, ARB use in combination with ACE inhibitors should be considered.
Aldosterone blockade should be used for post-MI patients—without significant renal dysfunction or hyperkalemia—who are already receiving therapeutic doses of an ACE inhibitor and β-blocker and who have a left ventricular ejection fractions of 40% or less, and have either diabetes or heart failure.
▸ β-Blockers. β-Blockers should be started and indefinitely continued in all patients who have had MI, acute coronary syndrome, or left ventricular dysfunction with or without heart failure symptoms unless contraindicated.
Other updated recommendations include the more stringent management of the following risk factors:
▸ Blood pressure control. The aim is to keep patients' blood pressure under 140/90 mm Hg or less than 130/80 mm Hg in patients with diabetes or chronic kidney disease through lifestyle modification. In patients who do not meet this goal, blood pressure medication should be added as tolerated. Initially treatment should be with β-blockers and/or ACE inhibitors, adding other drugs such as thiazides as needed to achieve target blood pressure.