New ESC Guidelines Stress Radial Access, 1-Hour Troponin Tests in NSTE-ACS Patients

September 15, 2015

GENEVA, SWITZERLAND — The European Society of Cardiology (ESC) has released new guidelines for the management of non-ST-segment elevation acute coronary syndrome (NSTE-ACS) patients, providing new guidance on the use of high-sensitivity troponin assays, dual antiplatelet therapy (DAPT), and the optimal time to start P2Y12 inhibition, among other aspects of care[1].

In addition, the new guidelines emphasize the transradial approach for vascular access because the radial route has been shown to reduce the risk of vascular complications, major bleeding events, and all-cause mortality, according to the new recommendations. The radial approach for vascular access is now a class 1A recommendation based on the results of the MATRIX study and an accompanying meta-analysis published early this year in the Lancet[2].

As reported by heartwire from Medscape, the MATRIX study included more than 8400 ACS patients, including those with and without STEMI, and showed that coronary interventions performed via the radial artery result in a significant reduction in net adverse clinical events (a combination of ischemic and bleeding end points). Importantly, the MATRIX study also showed the radial approach was associated with a statistically significant reduction in all-cause mortality.

Dr Marco Roffi (University Hospital, Geneva, Switzerland), the chair of the ESC writing committee for the new NSTE-ACS guidelines, said support for transradial access was strengthened by an updated meta-analysis, one that included the RIVAL and MATRIX studies, as well as other smaller studies, showing the radial approach resulted in a significant reduction in major bleeding, death/MI/stroke, and all-cause mortality compared with femoral access.

"Obviously, we have to say these data hold true in centers experienced with the radial approach," Roffi told heartwire . "Now we encourage all centers that take care of patients with ACS—again, this applies only to ACS patients; we don't know if the same holds true for stable patients—to embrace the radial technique and to switch approaches."

Importantly, Roffi said physicians and clinical centers should not abandon the femoral technique or forget about femoral access while in training.

"It is important that femoral skills be maintained," he said. "This is not a problem for a physician trained in femoral who switches to radial, but a fellow might be fully trained in radial access and have little experience with femoral. The femoral approach is still necessary for some procedures, like intra-aortic balloon-pump counterpulsation, structural heart disease interventions, such as [transcatheter aortic-valve replacement] TAVR, and peripheral artery disease interventions. The challenge for the younger generation will be to keep up their femoral skills."

The ESC guidelines for the management of NSTE-ACS in patients were released at the European Society of Cardiology (ESC) 2015 Congress this past month and published simultaneously in the European Heart Journal.

Use of 1-Hour Cardiac Troponin Assays

In addition to changes in vascular access, the ESC guidelines for managing NSTE-ACS patients propose a new algorithm for NSTEMI "rule-in" and "rule-out" based on high-sensitivity cardiac troponin assessment at presentation and at 1 hour.

The current protocol of measuring high-sensitivity troponin at baseline and 3 hours remains valid, with a class IB recommendation, but the new guidelines allow centers to assess cardiac troponin at presentation and 1 hour after presentation, with the rapid rule-out/rule-in protocol using high-sensitivity cardiac troponin also given a class IB recommendation.

"The 1-hour algorithm is faster and even better validated than the 3-hour algorithm," said Roffi. "It allows us to have a faster diagnosis to rule in MI or, equally important, rule out the patient who does not have MI. You can either discharge the patient or check for alternative diagnoses. In the latter case, you can speed up the management of those patients without compromising the predictive value of the assessment."

Importantly, patients with two negative high-sensitivity cardiac troponin tests are at very low risk of MI or mortality, and, in the absence of alternative diagnosis mandating hospital admission, they can be discharged. If required, further tests such as stress testing may be performed on an outpatient basis. "Based on the major diagnostic advances conveyed by high-sensitivity cardiac troponin assays, as Europeans we are puzzled by the fact that these diagnostic modalities are not yet approved in the US," stated Roffi.

Another of the changes in the new European guidelines deals with the initiation of P2Y12 inhibition in patients scheduled for invasive procedures. In the past, including the 2011 clinical guidelines, starting treatment was recommended soon after the diagnosis, but this is no longer the case, at least with prasugrel (Effient, Lilly/Daiichi Sankyo). Roffi explained that data from the ACCOAST study does not support its use.

"It is not recommended to pretreat the patient scheduled for early coronary angiography with prasugrel," said Roffi. "ACCOAST showed, with some surprise to many of us, there was no benefit in terms of ischemic-event reduction and a significant increase in major bleeding."

The previous guidelines, said Roffi, were somewhat "overconfident" in recommending P2Y12-inhibition pretreatment, in addition to aspirin, soon after the ACS diagnosis was made. ACCOAST tempered that enthusiasm. He added that the optimal time of administering ticagrelor (Brilinta, AstraZeneca) or clopidogrel is not known in patients scheduled for invasive procedures, as this has never been properly investigated, so the 2015 NSTE-ACS guidelines make no recommendations for or against pretreatment with these agents.

"We know this is an area of uncertainty," said Roffi in reference to the question of pretreatment with ticagrelor and clopidogrel. "We would have liked to give guidance, but we can't because there are no data."

Guidance on DAPT

With the 2015 clinical guidelines, the standard duration for treatment with a P2Y12 inhibitor and aspirin remains 12 months unless there are other associated conditions, such as excessive risk of bleeding. The 12-month duration for DAPT is a class IA recommendation. Now, however, the guidelines offer some leeway for physicians, opening the door to shorter and longer durations of DAPT depending on the patient's risk of bleeding and subsequent ischemic events.

"If you have a patient with a high bleeding risk, you're now allowed to reduce the time of dual antiplatelet therapy," said Roffi. "If you have a patient at high risk for ischemic events, you're allowed to prolong it."

The guidance on shortening or extending DAPT beyond the standard 1-year duration are "weak" recommendations—an option a physician "may consider"—and both are given a class IIB recommendation with a level of evidence B (IIB: "usefulness of efficacy is less well established by evidence or opinion"). Roffi told heartwire the guidelines recommend physicians reevaluate a patient after 12 months before making a decision to go longer than 1 year.

Roffi stressed the present DAPT recommendations are for patients with NSTE-ACS. In stable patients, the trend is to reduce the length of DAPT, given improvements in stent technology and the diminishing risks of stent thrombosis. With ACS patients, however, the duration of DAPT is also intended to prevent secondary events unrelated to the stent.

Some Q&A for the Real World

The 2015 guidelines also provide some direction for managing antiplatelet therapy in patients who need chronic oral anticoagulants, such as vitamin-K antagonists or the novel oral anticoagulants. It also includes guidance on how to manage NSTE-ACS patients taking antiplatelet agents who are undergoing CABG surgery or who have atrial fibrillation.

Given the complexity of managing ACS patients, the ESC writing committee also published three companion manuscripts in the European Heart Journal [3–5]. The three papers are based on case descriptions and include questions and detailed answers on how to manage, based on the guidelines, the individual patient in multiple clinical scenarios. The companion papers include questions and answers related to diagnosis and risk assessment, coronary revascularization, and antithrombotic therapy.

"Obviously, the guidelines come from the perspective of large clinical trials and are evidence based and provide guidance for the management of patient groups, but the questions and answers provide, hopefully, a different perspective: what should I do with this patient or how do I apply the guidelines in this patient?" said Roffi. He added the Q&A also highlight certain "gray zones" where there might not be a lot of data, although they do attempt to provide some guidance/advice for treating such patients.

Roffi reports research funding from Bayer and compensation from AstraZeneca, Eli Lilly, and Merck in the past 3 years. Disclosures for the coauthors are listed on the journal website.


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