Dual Antiplatelet Therapy After Percutaneous Coronary Intervention

Abstract

Background Pharmaceutical care issues related to prescribed dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI), such as non-adherence and adverse effects, are reported to be common problems occurring post-discharge from hospital. Purpose To assess adherence to DAPT and identify adverse effects experienced post-PCI. Material and methods Following ethics approval and informed written consent, 100 patients on DAPT post-PCI were consecutively recruited over 3 months (February to April 2016) from the catheterisation laboratory at the local general hospital. A validated data collection form was completed for each patient at the time of recruitment (t=0). Telephone interviews were undertaken 1 month after PCI (t=1) and were repeated 6 months post-PCI (t=2). During the interviews, adherence to DAPT was assessed using the validated Morisky Medication Adherence Scale (MMAS-8) and adverse effects reported by the patients were documented. A total MMAS-8 score of 0 indicates 'high' adherence, 1-2 'medium' adherence and 3-8 'low' adherence. Changes in adherence between t=1 and t=2 were assessed using the χ2 test. Results Of the 100 patients, the majority (n=81) were men with a mean age of 65 years (range 38-88 years). 98 patients were followed-up at t=1. MMAS-8 scores were classified as 'high' (n=74), 'medium' (n=21) and 'low' (n=3) adherence for aspirin and 'high' (n=76), 'medium' (n=20) and 'low' (n=2) adherence for clopidogrel. 16 patients reported common adverse effects which may be related to DAPT, including minor bleeding (n=6), dyspepsia (n=6), bruising (n=3) and diarrhoea (n=1). To date, 73 patients were followed-up at t=2. At t2, MMAS-8 scores were classified as 'high' (n=50), 'medium' (n=15) and 'low' (n=8) adherence for aspirin and 'high' (n=46), 'medium' (n=18) and 'low' (n=9) adherence for clopidogrel. 35 patients reported common adverse effects which may be related to DAPT, including bruising (n=18), minor bleeding (n=9) and dyspepsia (n=8). Mean MMAS-8 scores were 0.23 (range 0-2) (t=1) and 0.74 (range 0-7) (t=2) for aspirin (p=0.055) and 0.23 (range 0-2) (t=1) and 0.84 (range 0-7) (t=2) for clopidogrel (p=0.016). Conclusion The results indicate a decrease in adherence to DAPT 6 months post-PCI. Interventions to improve adherence and decrease adverse effects, such as patient education by pharmacists before discharge from hospital, are proposed.