SIHD affects nearly 10 million Americans, and remains the leading cause of death among U.S. adults. As such, the new guidelines present an extensive assessment of the evidence and key issues involved in the diagnosis, risk assessment, treatment and follow up of known or suspected SIHD. Among the topics covered: guideline-directed medical therapy as the cornerstone of treatment for most patients; how to optimally care for women and other subgroups of patients who may be more prone to complications; the use of newer imaging and diagnostic technologies; the role of catheter-based and surgical procedures in treatment; the value of patient preferences in decision making; and the need for careful follow up to monitor for progression of disease and adherence to therapy.
Specifically, the guidelines recommend that patients diagnosed with SIHD should undergo assessment of risk for death or complications of IHD. For patients with an interpretable ECG and who are able to exercise, a standard exercise test should be the first choice test for diagnosis of IHD, especially if the likelihood is intermediate. Those who have an un-interpretable ECG and are able to exercise, should undergo an exercise stress with nuclear MPI or echocardiography, particularly if the likelihood of IHD is intermediate to high. For patients unable to exercise, nuclear MPI or echocardiography with pharmacologic stress is recommended. However, it's important to note that routine annual stress and imaging studies are generally not recommended in stable patients unless there are changes in clinical circumstances. While an earlier ACC/AHA guideline on chronic stable angina issued in 2002 focused on specific drugs and interventions to reduce individual cardiovascular risk factors, the new document also represents a more patient-centered approach to managing SIHD.
The new guidelines recommend that patients with SIHD generally receive a "package" of Guideline-Directed Medical Therapy (GDMT) that includes lifestyle interventions and medications shown to improve outcomes which includes (as appropriate):
- Diet, weight loss and regular physical activity;
- If a smoker, smoking cessation;
- Aspirin 75 – 162 mg daily;
- A statin medication in moderate dosage;
- If hypersensitive, antihypertensive medication to achieve a BP <140/90;
- If diabetic, appropriate glycemic control.
That being said, the writing committee notes throughout the document that patients need to be informed and engaged in their own care. "Patient preference is very important in terms of directing care, so the answer may not be the same for every patient," said Julius M. Gardin, MD, FACC, of Hackensack University Medical Center and vice chair of the writing committee. "Additionally, to provide quality care, we need to consistently devote time to each patient to educate them about the things that they can do in terms of self-care – stopping smoking, watching their diet, losing weight, getting regular exercise and taking their medications as prescribed."
The writing committee also took a stance on when to use more invasive strategies. For the vast majority of patients with stable disease – even those with considerable ischemia – medical management is warranted before considering revascularization by placing a stent in the blocked artery or through surgical bypass grafting. "Overall, there is a misperception that somehow opening up and stenting an artery saves lives for patients with stable disease; however, in the majority of these cases there is no evidence from any study that this procedure prolongs life," said Gardin.
The new guideline was developed by experts at ACC and AHA in partnership with the American College of Physicians, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and The Society of Thoracic Surgeons without commercial support. The recommendations were also informed by discussions with other ACC writing committees to ensure consistency.