New ‘Chronic Coronary Syndrome’ Guidelines Stress There’s Nothing Stable About CAD

PARIS, France—There are new European Society of Cardiology (ESC) guidelines out today for the diagnosis and management of what’s now being termed “chronic coronary syndromes” (CCS). The document, which updates 2013 guidelines on stable coronary artery disease is effectively retiring this term in order to emphasize that the disease is anything but stable.

“The disease can have long, stable periods but can also become unstable at any time, typically due to an acute atherothrombotic event caused by plaque rupture or erosion,” the guidelines state. “However, the disease is chronic, most often progressive, and hence serious, even in clinically apparently silent periods.”

This shift to this new terminology, according to Juhani Knuuti, MD (Turku University Hospital, Finland), who chaired the guideline writing group with William Wijns, MD (The Lambe Institute for Translational Medicine and Curam, Galway, Ireland), was in part to make the point that this disease warrants different approaches at different times. “You may have stable phases and less stable phases, because in most cases, the disease is advancing. But you can also intervene on the disease, you can prevent it from advancing, and you may be able to prevent events that are coming,” Knuuti told TCTMD.

To better diagnose and manage these different phases of the syndrome, the 2019 CCS guidelines focus on the six most common clinical scenarios encountered—very often in the outpatient setting, Knuuti noted. These are patients with angina and suspected CAD; patients with new onset heart failure or left ventricular dysfunction and CAD; asymptomatic and symptomatic patients with stabilized symptoms less than 1 year after an initial CAD diagnosis or revascularization; patients with angina and suspected vasospastic or microvascular disease; and asymptomatic subjects in whom CAD is detected at the time of screening.

A key aspect of the new guidelines is their recognition that the pretest probability of disease in patients presenting with chest pain is dramatically reduced. “It's now about one-third the prevalence of the disease as compared to 2013 ESC guideline numbers,” Knuuti said. “So when you have a patient in front of you, you need to rethink completely what type of test, what kind of approach to take, because the likelihood of having the disease has gone down so much.” 

As such, the recommended diagnostic tests, depending on whether a given patient has a low, moderate, or high likelihood of disease, have shifted in prominence. Invasive tests are primarily recommended in patients at high pretest probability of having disease, while functional tests—SPECT imaging and stress echo, etc—are recommended in patients in the middle ranges. But for the growing proportion of patients in whom CAD seems unlikely, CT angiography is recommended.

“In a sense, the main difference from the previous version of the guidelines is that because the likelihood of having the disease has gone so much down, we are having more patients that have low likelihood of having obstructive disease,” Knuuti explained. “So that means that CT angiography becomes more and more commonly used.”

Drugs, Imaging, and Interventions

Several new recommendations in the 2019 guidelines pertain to the use of antithrombotic therapy, in particular the addition of a second antithrombotic drug to aspirin for long-term secondary prevention in patients at high risk of ischemic events who are at low risk for bleeding. Also, in patients with CCS and atrial fibrillation, or patients post-PCI with A-fib or another indication for anticoagulation, a non-vitamin K antagonist oral anticoagulant (NOAC) is now recommended over a vitamin K antagonist.

A section on revascularization in the new guidelines summarizes the recent evidence supporting a role for PCI or CABG for relieving symptoms as well as improving prognosis. The cumulative evidence to date, said Knuuti, particularly from trials using fractional flow reserve (FFR) to identify ischemia-producing stenoses, suggests that PCI in stable coronary disease not only improves symptoms but can also reduce the risk of MI. As such, the current guidelines contain stronger recommendations for the use of PCI in patients identified on FFR as having angiographic stenosis in large vessels causing a significant intracoronary pressure gradient.

Lastly, guideline writers were careful to emphasize the importance of lifestyle, diet, pollution exposure, and other primary prevention measures that have typically been given short shrift in prior CAD guidelines. “Often we're talking about the drugs and interventions, but in this guideline, prevention is key,” Knuuti said. “We're talking about a chronic disease, which is advancing, so prevention through lifestyle, quitting smoking, diet, and exercise are very important and should be incorporated in all of these patients.”

The CCS guidelines are one of five new guidance documents released today at the ESC Congress 2019. A special effort was made to ensure that all of these guidelines were “synchronized” with one another, Knuuti noted. In the case of the CCS guidelines, that includes information on the management of patients with diabetes and coronary artery disease which echoes new guidance set out in separate recommendations, released today, on the management of diabetes, prediabetes, and cardiovascular diseases.

“I do think that they will be of interest and value to the clinical community,” said Patrick O’Gara, MD (Brigham and Women’s Hospital, Boston, MA), an American College of Cardiology (ACC) spokesperson who commented on the new guidelines for TCTMD. The shift to “chronic” as a label for this particular document, he continued, enables the guideline writers to cover a range of updates related to the evaluation and management of atherosclerotic disease “under a larger umbrella,” and over the lifecycle of the disease.

As for whether he thinks the term will catch on in clinical practice, O’Gara said that “remains to be seen.”

“Perhaps this title is drawing attention to the fact that patients with stable CAD are susceptible to periods of instability, re-stabilization, and instability,” which is a worthwhile message, he said.

Asked what clinicians may find especially novel in this document, O’Gara pointed to the “continued iterations” of themes in previous ACC/American Heart Association and ESC guidelines related to noninvasive testing and indications for revascularization. The updates on the use of antithrombotics in this setting are particularly useful as a one-stop shop given the growing number of scenarios in which physicians need to make informed decisions about double- and triple-therapy.