The need for dedicated DAPT
The need for dedicated DAPT updates is well justified by the large amount of data and new information generated in the field over the past few years. As expected, the ACC/AHA and ESC updates contain large areas of overlap as well as some differences. Differences were largely explained by the different times of publication of the 2 documents rather than a different interpretation of the evidence available at that azd2171 synthesis time. Indeed, the 2017 ESC update was published 1.5 years after the 2016 ACC/AHA update, thus allowing for more chance to incorporate the newest data, and also to put into perspective data that were new when the 2016 ACC/AHA document was published. With respect to antiplatelet therapy, the ESC/European Association for Cardio-Thoracic Surgery guidelines for myocardial revascularization, released in 2018, essentially reflect the recommendations provided in the 2017 ESC update on DAPT with few notable exceptions mentioned in the following text .
From a methodological standpoint, the 2016 ACC/AHA update was built around 3 critical questions related to the duration of DAPT, which served as the basis for a formal systematic review and evaluation of the available data . The writing group consisted of the chairs, vice-chairs, and members of previous guidelines tackling the topic of DAPT. Conversely, the 2017 ESC update was built in keeping with recommendations for formulating and issuing ESC guidelines by a selection of experts in the field, based on a comprehensive review of the published evidence . This paper aims to review and compare the ACC/AHA and ESC updates for DAPT to delineate common domains, consistent messages, and differences in recommended management strategies across the Atlantic. Meanings and suggested phrasings of Class of Recommendation (COR) and Level of Evidence (LOE) for each update are summarized in and . While the interpretation of the COR I and III is straightforward, the COR IIa and IIb imply conflicting evidence or divergence of opinion regarding the relative benefit and risk of a given treatment or procedure. In general, when the COR is IIa, the weight of the evidence or opinion is in favor of the treatment or procedure, whereas a COR IIb implies that there is not enough data to make a more definitive recommendation, the data may be somewhat contradictory, or the benefit may be extremely modest. Notably, despite some subtle differences that exist in criteria for and phrasing of COR and LOE in the ACC/AHA and ESC updates, the general meaning is essentially consistent. Common themes in both the ACC/AHA and ESC focused updates include risk stratification, the type and initial timing of P2Y inhibitor administration, the duration of DAPT in different patient scenarios, the use of proton pump inhibitors, and the management of antiplatelet therapy in patients on oral anticoagulation , . Some areas of controversy (e.g., drug-to-drug interactions, platelet function and genetic testing, bridging of antiplatelet agents in the perioperative period, and dual-pathway inhibition therapy with both antiplatelet and anticoagulant agents) are either not addressed or only briefly discussed due to lack of conclusive data supporting specific recommendations.
Recommendations on DAPT Duration Recommendations on DAPT duration play a major part in the ACC/AHA and ESC focused updates and are discussed in the following paragraphs 6, 7. For each clinical scenario, an evidence summary is provided, followed by a description of specific recommendations (Central Illustration, Figure 4).
Antiplatelet Therapy in Patients on Oral Anticoagulation The 2016 ACC/AHA update does not provide specific recommendations for patients who require concomitant antiplatelet and anticoagulant therapy (6), which is a topic covered by a North American consensus document to which they refer to and which has been recently updated after the release of the guidelines 58, 59; however, the update gives general guidance on the approach to such patients. Moreover, none of the trials using the non–vitamin K oral antagonists were available at the time these recommendations were written. In contrast, the 2017 ESC update covers the topic based essentially on 3 randomized trials that investigated antithrombotic strategies to improve the safety of triple antithrombotic therapy with oral anticoagulation and DAPT 60, 61, 62. Importantly, none of these studies were adequately powered for detecting differences in ischemic endpoints. The results of an additional trial of PCI patients with atrial fibrillation, showing that dual therapy with dabigatran at the doses of 150 or 110 mg reduces bleeding as compared with triple antithrombotic therapy, were not available at the time of publication of both the ACC/AHA and ESC updates (63). Further guidance on the topic in the context of similar recommendations is given by a recent European expert consensus document (64).