The 2014 American College of Cardiology ACC/American Heart Association Guideline for the Management of Patients With Non–ST‐Elevation Acute Coronary Syndromes

The new title, “Non–ST-Elevation Acute Coronary Syndromes (NSTE-ACS),” for this full revision of the 2007 American College of Cardiology Foundation/American Heart Association guideline titled “Unstable Angina/Non–ST-Elevation Myocardial Infarction,” more concisely emphasizes the continuum between unstable angina (UA) and non–ST-elevation myocardial infarction (NSTEMI). They can be indistinguishable at presentation and therefore are considered together using the terminology non–ST-elevation acute coronary syndromes. Approximately 70% of patients with an acute coronary syndrome have an NSTE-ACS, comprising more than 625 000 patients annually.1 In the appropriate clinical context, if cardiac biomarkers are normal, the patient is deemed to have UA; if troponins are elevated, the patient is considered to have an NSTEMI.2 Additional new terminology relates to the initial strategy for management of patients with NSTE-ACS. The initial treatment pathways have been recategorized into, as previously, an early invasive strategy, seeking to rapidly risk stratify patients by angiographic assessment of their coronary anatomy with intent to perform revascularization when appropriate. The new designation, an ischemia-guided strategy, has replaced the previous term, initial conservative therapy, to more clearly convey the physiologic rationale of this approach. Ischemia-guided strategy involves guideline-directed medical therapy, with coronary angiography only if the patient experiences refractory or recurrent ischemic symptoms or develops hemodynamic instability. Despite landmark advances in the care of patients with NSTE-ACS, emerging diagnostic and therapeutic strategies have posed new challenges. Evidence-based decisions will require comparative effectiveness studies of available and novel potent antiplatelet agents that are indicated, in addition to anticoagulant therapy irrespective of the initial treatment strategy. The paradox of newer and more potent antithrombotic and anticoagulant drugs that reduce major adverse cardiac outcomes but increase bleeding risk occurs with the greatest frequency in patients with atrial fibrillation. Atrial fibrillation patients who develop NSTE-ACS and receive a coronary stent are the population at risk from triple anticoagulant/antiplatelet therapy. The optimal regimen requires ascertainment. The use of cardiac troponin, the preferred biomarker of myocardial necrosis, is rapidly evolving. Although a truly high-sensitive cardiac troponin is not currently available in the United States, the sensitivity of contemporary assays continues to increase, accompanied by higher rates of elevated cardiac troponin unrelated to coronary plaque rupture. This diagnostic quandary necessitates investigation, potentially addressing measurement of absolute cardiac troponin change rather than traditional analysis of relative alterations. More than half of the NSTE-ACS mortality occurs in older patients, with this high-risk cohort increasing as our population ages. An unmet need is to more clearly distinguish their optimal management strategies. An appreciable number of NSTE-ACS patients have angiographically normal or nonobstructive coronary artery disease; women predominate in this population and their prognosis is not benign. Clinical advances are predicated on clarification of the pathophysiology of this challenging syndrome. A fundamental aspect of all clinical practice guidelines is that these evidence-based documents cannot encompass all clinical circumstances, nor can they replace the judgment of individual physicians in the management of each patient. The science of medicine is rooted in evidence and the art of medicine is based on the application of this evidence to the individual NSTE-ACS patient.