Original Title: Clopidogrel versus Aspirin as an Antiplatelet Monotherapy after 12-Month Dual-Antiplatelet Therapy in the Era of Drug-Eluting Stents. Reference: Taek Kyu Park et al. Circ Cardiovasc Interv. 2016 Jan;9(1):e002816.

Courtesy of Dr. José Amadeo Guillermo Álvarez.

The use of dual antiplatelet therapy (DAPT) over 12 months after hospitalization for acute myocardial infarction (AMI) or drug eluting stent implantation (DES) could, in some subgroups of patients, reduce ischemic events at the expense of a higher risk of bleeding. However, no evidence supports a sound recommendation over the best antiplatelet after a 12 month DAPT treatment. This is an observational study carried out between 2003 and 2010 that compares the clinical evolution of 3243 patients receiving DES and 12 month DAPT. Patients were divided in two groups, those prescribed aspirin (n=2472) and those prescribed clopidogrel (n=771). Patients in the clopidogrel group had more comorbidities and more complex lesions than those in the aspirin group.

After a 36 month follow up, clopidogrel monotherapy resulted in a significant reduction of the final end point, the combination of death, AMI or stroke (aspirin vs. clopidogrel 3.8% vs 2.6% HR 0.54; CI 95% 0.32-0.92; p=0.02) and of cardiac mortality (aspirin vs. clopidogrel 1.4% vs 0.5%; HR 0.31; CI 95% 0.11-0.93; p=0.04). Major bleeding (TIMI) was similar in both groups (0.9% vs 1.3%; HR 1.03; CI 95% 0.46-2.32: p=0.95).

Conclusion
After 12 months of dual antiplatelet therapy, clopidogrel monotherapy instead of aspirin could be associated to a lower risk of ischemic events in patients receiving a DES.

Editorial Comment
We should bear in mind this registry did not randomize the administered drugs. Even though the population in the aspirin group has characteristics of lower clinical and angiographic risk, most of these patients received first generation DES (sirolimus or paclitaxel, 64.3%), whereas most of patients in the clopidogrel group received everolimus or zotarolimus eluting stents (68.2%), and even though the authors do mention the logistic regression analysis found no correlation between primary end point and type of stent or time of PCI, the results should take into account the number of patients.

The hypothesis stating that clopidogrel is superior to aspirin after post DES 12 month DAPT, calls for further analysis in a larger prospective, randomized study.

Courtesy of Dr. José Amadeo Guillermo Álvarez.