USE AND OUTCOME OF DUAL ANTIPLATELET THERAPY FOR ACUTE CORONARY SYNDROME IN PATIENTS WITH CHRONIC KIDNEY DISEASE: INSIGHTS FROM THE CANADIAN OBSERVATIONAL ANTIPLATELET STUDY (COAPT), A MULTICENTRE PROSPECTIVE COHORT STUDY

Chronic kidney disease (CKD) increases the risk of adverse outcomes in acute coronary syndrome (ACS). The optimal regimen of dual antiplatelet therapy (DAPT) post percutaneous coronary intervention (PCI) is challenging due to both increased bleeding and thrombotic risks in patients with CKD, particularly since these patients were under-represented in randomized controlled trials. We examined the patterns of DAPT use in ACS patients post PCI stratified by presence of CKD.

The multi-centre prospective Canadian Observational Antiplatelet Study (COAPT) enrolled patients with an ACS diagnosis from 43 hospitals between December 2011-May 2013. The present study is a subgroup analysis comparing type and duration of DAPT, and associated outcomes among patients with and without CKD defined as eGFR < 60 ml/min/1.73m2 (calculated by CKD-EPI). COAPT enrolled 1921 patients (mean age: 61; 21.4% female) with a median eGFR of 85 ml/min/1.73 m2 (25th and 75th percentiles [69, 97]). Of those, 275 (14.3%) had CKD. CKD patients were older, more likely to be female and have comorbidities including previous ACS, heart failure, hypertension, cerebrovascular disease, atrial fibrillation and gastrointestinal bleeding. Patients with CKD were less frequently prescribed the more potent P2Y12 inhibitors prasugrel/ticagrelor (18.5% vs 25.8%, p=0.01) and had a shorter duration of DAPT therapy than patients without CKD (median 382 vs 402 days, p=0.003). CKD was associated with major adverse cardiovascular events (MACE) at 12 months (p < 0.001) but not bleeding when compared to patients without CKD (figure 1). CKD was associated with MACE in both patients on prasugrel/ticagrelor (p=0.017) and those on clopidogrel (p < 0.001) (p for heterogeneity=0.70). CKD was associated with increased bleeding only among patients receiving prasugrel/ticagrelor (p=0.007), but not among those receiving clopidogrel (p=0.64) (p for heterogeneity=0.036). Patients with CKD were more frequently considered to have an ongoing indication for DAPT therapy during follow-up. Discontinuation of DAPT was more likely in patients with CKD due to the need for an oral anticoagulant.

Patients with CKD had a shorter DAPT duration and were less frequently prescribed potent P2Y12 inhibitors than patients without CKD. Overall, compared with patients without CKD, patients with CKD had higher rates of MACE and similar bleeding rates. However, among those prescribed more potent P2Y12 inhibitors, CKD was associated with more bleeding than those without CKD. Further studies are needed to better define the benefit/risk ratio, and establish a more tailored and evidence-based DAPT regimen for this high-risk patient group.