Updated Recommendations for the Management of Stable Ischemic Heart Disease

Stable ischemic heart disease (SIHD) affects millions of Americans, with substantial impact on survival and quality of life. Management of these patients can be complex. There are multiple available modalities for diagnosis, risk stratification, medical treatment, and revascularization of SIHD. Controversies abound, particularly with regard to indications for revascularization and percutaneous versus surgical approaches. As such, high-quality practice guidelines provide an important resource focused on objective interpretation of the evidence. The 2014 ACC/AHA/AATS/PCNA/SCAI/STS Focused Update of the Guideline for the Diagnosis and Management of Patients with Stable Ischemic Heart Disease (SIHD), coming only 2 years after the 2012 Guideline,¹ demonstrates the rapid advancement of knowledge in this field.

First, it is worth noting that the bulk of the 2012 Guideline has not changed. For example, non-invasive stress testing is preferred for the diagnosis and risk stratification of coronary artery disease (CAD). Treatment of SIHD focuses on minimizing mortality while maximizing quality of life, and guideline-directed medical therapy remains the therapeutic cornerstone. When medical therapy isn’t enough to relieve symptoms, revascularization procedures can be considered, with ample attention paid to risk/benefit ratio and patient preferences. For some high-risk patients with complex coronary disease, revascularization may improve survival. This is one of four areas that we highlight for which the Writing Group provides important updated guidance.

1. Diagnostic coronary angiography—The 2014 Focused Update fills a gap in the 2012 Guidelines: Recommendations for the use of coronary angiography for diagnosis of CAD. At this time, despite technological improvements in non-invasive testing and increasing use of coronary CT and cardiac MRI, invasive coronary angiography remains the most useful test to identify and characterize patients with complex CAD. However, National Cardiovascular Data Registry’s CathPCI Registry data show that over half of patients undergoing elective coronary angiography have non-obstructive coronary disease.² The Focused Update provides a Class IIa recommendation for coronary angiography for patients with a high likelihood of severe coronary disease based on clinical characteristics and non-invasive testing and for patients who are candidates for revascularization. When patients have symptoms that are refractory to optimal medical therapy, this recommendation becomes Class I. While the Writing Group generally supports a strategy of non-invasive stress testing prior to angiography, they acknowledge that, in some cases, coronary angiography for diagnosis can occur without stress testing, particularly when there is high likelihood for “severe CAD for which revascularization would confer a survival advantage.” Coronary angiography can also be used to establish or reject a CAD diagnosis for a patient with otherwise equivocal testing, as this could lead to change in management strategy. Guideline-directed medical therapy is not without cost and potential adverse effects. In some instances, invasive angiography may be the best way to ensure these therapies are applied only to individuals who do, in fact, have CAD. All angiography recommendations come with an important caveat: “There are no high-quality data upon which to base recommendations about when to perform diagnostic coronary angiography,” and, thus, the recommendations are “Level of Evidence C.” To date, all trials comparing guideline-directed medical therapy to revascularization have required the use of coronary angiography. We, like the Writing Group, eagerly await the results of the ongoing ISCHEMIA trial, which tests a strategy of SIHD treatment without coronary angiography. It should be noted, however, that the ISCHEMIA trial does require an anatomic test, CT angiography, to exclude patients with left main stenosis and without obstructive CAD.


2. Revascularization to improve survival including use of a “Heart Team” approach—Randomized controlled trials, mostly performed in the 1970s and 1980s, demonstrate a survival benefit of coronary artery bypass graft (CABG) when compared with medical therapy, especially in the setting of left main and/or 3-vessel CAD.³ Subsequent studies have focused on defining the best method of revascularization and most appropriate patient population. Previous guidelines have generally expressed a preference for CABG over percutaneous coronary intervention (PCI) for patients with SIHD when improved survival is the goal. The Focused Update strengthens this recommendation for patients with diabetes and multi-vessel CAD. CABG is now “generally recommended” over PCI (Class I recommendation) to improve survival. This upgraded recommendation (from IIa, “probably recommended”) reflects integration of the results of the FREEDOM (Future Revascularization Evaluation in Patients With Diabetes Mellitus: Optimal Management of Multivessel Disease) trial with prior data from the SYNTAX and BARI trials. FREEDOM randomized 1900 patients with diabetes and multi-vessel disease (>70% stenosis of at least 2 epicardial vessels, without significant left main stenosis) to CABG or PCI with drug-eluting stent placement. Five-year rates of the primary endpoint (composite of death, MI, or stroke) were significantly lower in the CABG group (18.7% vs. 26.6%, p=0.005),³ at least a trend for improved survival.

   Because best decisions as to when to revascularize with PCI or CABG in patients with diabetes and multivessel disease involve assessment of complex issues, and because the trials comparing strategies used this approach, the Writing Committee recommends a multidisciplinary approach composed of interventional cardiology and cardiac surgery. This Heart Team should review the patient’s medical issues and anatomy, feasibility of revascularization approaches, and patient preferences.



3. Left main disease—The Writing Group also further evaluated use of CABG versus PCI for the treatment of unprotected left main CAD. They cited a recent Bayesian meta-analysis⁴ as additional evidence that mortality is similar when these two revascularization strategies are applied to selected patients. Though overall recommendations are unchanged, this Focused Update provides additional support for the use of PCI for revascularization in selected patients of unprotected left main disease when patients have a low/intermediate SYNTAX score and elevated surgical risk.


4. Alternative therapies for SIHD—The Update provides lukewarm support for chelation and for enhanced external counterpulsation (EECP). The Trial to Assess Chelation Therapy (TACT) randomized patients with prior myocardial infarction to chelation therapy or placebo. The primary endpoint (a composite of mortality, recurrent MI, stroke, revascularization, or hospitalization for angina) was less frequent in the chelation group (26% vs 30%, p=0.035).⁵ Due to concerns about the “modest overall benefit, high number of patient withdrawals, absence of adequate scientific basis for the therapy, and the possibility of a false-positive outcome,” the Writing Group provided only a Class IIb recommendation for chelation, noting “the usefulness of chelation therapy is uncertain for reducing cardiovascular events in patients with SIHD.” This represents an upgrade, however, from the prior Class III recommendation. The Focused Update provides a similar re-examination of EECP, although without reporting any new data. EECP “may be considered for relief of refractory angina,” a Class IIb recommendation that is unchanged from the 2012 Guideline.

Guidelines in the field of SIHD have the unenviable task of attempting to hit a moving target. Technological advances push the boundaries of SIHD diagnosis and treatment, and large clinical trials regularly produce new and sometimes contradictory results. This update provides important new guidance.