Prolonged Dual Antiplatelet Therapy in Acute Myocardial Infarction Patients without Revascularization: Results from a China Acute Myocardial Infarction (CAMI) registry study

Background: At least 12-month dual antiplatelet therapy (DAPT) is one of the standards of care following Percutaneous Coronary Intervention (PCI) in patients with acute coronary syndrome. However, study on prolonged DAPT for acute myocardial infarction (AMI) patients without revascularization is limited. Methods: We studied 1744 AMI patients without revascularization from the China Acute Myocardial Infarction registry between January 2013 and September 2014. These patients were on DAPT and did not experience AMI, stroke, or bleeding events at 12-month follow-up. We divided them into two groups: 12-month DAPT group (DAPT for at least 12 months but less than 18 months) and 18-month DAPT group (DAPT for at least 18 months). The primary outcome is 24-month all-cause death. Results: Overall, 1221 (70.0%) patients took DAPT for ?12 months but <18 months, while 523 (30.0%) patients took DAPT for ?18 months. The two groups had comparable proportions with high ischemic risk (27.0% vs. 25.6%, P = 0.5418), as well as high bleeding risk (29.0% vs. 28.5%, P = 0.8316). At 24 months, the all-cause mortality rate of 18-month DAPT group was significantly lower than that for 12-month DAPT group (3.7% vs 5.9%, P = 0.0471). Adjusted hazard ratio for all-cause death also showed statistical significance (0.59, 95% CI: 0.35-0.99, P = 0.0444). Conclusions: DAPT for at least 18 months was associated with lower 24-month mortality for non-revascularization AMI patients without events within 12 months after onset. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial NCT01874691 ### Funding Statement This study was supported by the Twelfth Five-Year Planning Project of the Scientific and Technological Department of China (2011BAI11B02) and CAMS Innovation Fund for Medical Sciences?CIFMS) (2020-I2M-C&T-B-050 and 2016-I2M-1-009). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The CAMI registry was approved by the Ethics Committee of Fuwai Cardiovascular Hospital (No. 431). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data referred to in the manuscript is available.