New Guidelines Emphasize Medical Therapy for Stable Ischemic Heart Disease

November 19, 2012

PHILADELPHIA — Lifestyle changes and medical therapy should be the mainstay for most patients with stable ischemic heart disease (IHD), according to what some say is a long-overdue update to guidelines for this patient group [1]. The primary focus of interventions in these patients, according to the new guidance, should be reducing the risk of premature cardiovascular death and nonfatal MI while maintaining activity levels and a quality of life.

"Because of the variation in symptoms and clinical characteristics among patients, as well as their unique perceptions, expectations, and preferences, there is clearly no single correct approach to any given set of clinical circumstances," state the new guidelines. "Patient education regarding various therapeutic options, appropriate levels of exercise, diet and weight control, and the importance of various clinical manifestations play a key role in achieving the treatment goal."

Published online November 19, 2012 in the Annals of Internal Medicine, the new guidelines, with lead author Dr Amir Qaseem (American College of Physicians, Philadelphia, PA), are a collaboration of the American College of Physicians, American College of Cardiology Foundation, American Heart Association, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, and the Society of Thoracic Surgeons.

The guidelines include 48 specific recommendations relevant for primary-care physicians and emphasize patient education, managing cardiovascular risk factors, a discussion of unproven risk-reduction strategies, the use of medical therapy to prevent MI and death and to relieve angina symptoms, the use of revascularization to improve survival and symptoms, and patient follow-up.

The initial approach to patient management focuses on eliminating all unhealthy behaviors, such as smoking, and promoting weight loss, physical activity, and a heart-healthy diet. Most important, the new guidelines provide an algorithm that emphasizes an evidence-based set of pharmacologic interventions intended to reduce the risk of future events. Drug therapy includes the use of antiplatelet agents, lipid-lowering drugs, particularly statins, and beta blockers. ACE inhibitors are recommended for many patients with stable IHD, such as those with diabetes or left ventricular dysfunction.

Medical Therapy First

Speaking with heartwire , Dr William Boden (Samuel Stratton VA Medical Center, Albany, NY), the lead investigator of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial, said that the treatment of stable IHD is a constantly moving target, but a full-scale revision of guidelines for the treatment these patients has not happened since 2002. With the publication of COURAGE and Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes (BARI 2D), it was believed these trials would likely spur the guideline rewrite, but even so, the update was at least three years in making.

"I think the guidelines were long overdue and very much needed, because so much has changed since 2002, both in our approaches to myocardial revascularization as well as medical therapy," said Boden. "Putting this all together was critically important. That said, I think the committee deserves enormous praise and credit because I think they largely got it right. I was particularly pleased to see that out of the gate they discuss the general approach to patient management, that being first and foremost to prevent death and complications from ischemic heart disease, myocardial infarction, and heart failure, and second to restore quality of life and manage symptoms."

The new guidelines strongly support the importance of medical therapy as the first-line treatment for patients with stable IHD. For Boden, the management algorithm, one that begins with lifestyle intervention and eliminating unhealthy behaviors, followed by secondary prevention and pharmacotherapy, is the right sequence of treatment events. "If the ultimate end game is to reduce death and myocardial infarction, then the best way to achieve that is to make sure that we invest heavily in patient education and to make certain that we underscore the importance of lifestyle intervention and secondary prevention," said Boden.

Beta blockers are recommended as the initial treatment for relief of symptoms in patients with stable IHD, and calcium-channel blockers or long-acting nitrates are recommended when beta blockers are contraindicated or cause unacceptable side effects or when initial treatment is unsuccessful. Sublingual nitroglycerin or nitroglycerin spray is recommended for the immediate relief of angina. Should symptoms persist after medical therapy, physicians are advised to consider coronary artery revascularization.

Tackling Patients in Need of Revascularization

For revascularization to improve symptoms, CABG surgery or PCI is recommended in patients with one or more significant (>70% stenosis) lesions. CABG surgery or PCI is not recommended in patients who do not meet the anatomic (>50% stenosis of the left main artery or >70% non-left main stenosis) or physiologic criteria for revascularization. In addition, PCI should not be performed if the patient is unable or unlikely to comply with dual antiplatelet therapy.

In addition, the guidelines recommend CABG or PCI to improve survival in several clinical scenarios, such as in patients with stenosis of the left main coronary artery, patients with lesions in three major coronary arteries, or patients with presumed ischemia-mediated ventricular tachycardia caused by a stenosis in a major coronary artery. PCI or CABG surgery is not recommended to improve survival in patients with stable IHD with one or more coronary lesions that are not anatomically or functionally significant.

Speaking with heartwire , Dr Daniel Simon (University Hospitals Case Medical Center, Cleveland, OH) said that there is increasing concern about the appropriateness of PCI procedures, and this has led to some uncertainty about the goals of treatment. He praises the new document, particularly the efforts to reduce cardiovascular morbidity and mortality through the appropriate application of revascularization strategies. As an interventional cardiologist, he raised some issues that he said are not addressed by the clinical guidelines.

"Knowledge of the coronary anatomy is critical," said Simon. "As the guidelines state, regardless of symptoms, if the patient has left main coronary artery disease or severe three-vessel disease, you revascularize for survival independent of symptoms. So the problem with all of these recommendations is that they recommend physicians do optimal medical therapy, including failing multiple drugs, and only then proceed to revascularization. But remember, the COURAGE trial and other trials that made a comparison between medical therapy and revascularization have always known the coronary anatomy first. This had led to concerns that patients with the most severe anatomy and those at risk for ischemia were never entered into those trials." It also means, he added, that the important information obtained from knowing the anatomy is already embedded in the new recommendations.

As a result of some of those concerns, the National Heart, Lung, and Blood Institute is sponsoring an eight-year trial in about 8000 patients to find the best management strategy for patients with stable ischemic heart disease and moderate to severe ischemia. The International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA), planned for at least 150 sites in more than 30 countries, will compare angiography and revascularization plus optimal medical therapy with the conservative strategy of optimal medical therapy only. As Simon notes, even patients randomized to medical therapy will undergo computed-tomography angiography to rule out left main or three-vessel disease.

Gun Shy Given Concerns About PCI Appropriateness

Simon noted that there is an assumption that PCI is being performed in patients who do not require it, but a recent Canadian study showed that PCI was underused in those with appropriate indications. This suggests that physicians have become "gun shy" about coronary revascularization given concerns about appropriateness, and he would like a statement included in the new guidelines highlighting the adverse effects of underusing PCI when it is clinically indicated. He also noted that coronary artery calcium (CAC) scans, which are not recommended anywhere in the document, can help physicians reclassify patients from intermediate risk to either high or low risk.

Although Simon and Boden both said the document is unlikely to please everybody, they praised the committee for the detailed, thoughtful analysis of the available evidence. For Boden, he was particularly pleased with the revascularization emphasis on a shared decision-making approach in patients undergoing revascularization because of left main or complex coronary disease. According to the new guidelines, the team should include a cardiac surgeon, an interventional cardiologist, and the patient. Although a general cardiologist was not included as part of the group, he thinks one should also be involved in the decision-making process.

A couple of notable trials shed even more light on the CABG-vs-PCI debate, including the recently published and presented Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of Multivessel Disease (FREEDOM) and FAME II studies. These trials were not used in the guideline-writing process, as the data were only presented within the past couple of weeks and months.

Interestingly, the guidelines recommend that chelation therapy not be used for the intention of improving symptoms or reducing cardiovascular risk in stable IHD patients. They state there is low-quality evidence supporting its use, but the recent Trial to Assess Chelation Therapy (TACT) challenges that, as the randomized, double-blind trial of chelation therapy showed it may modestly improve clinical outcomes in patients after an acute MI.