The dual antiplatelet therapy (DAPT) de-escalation strategy is considered and used by many clinical physicians when treating acute coronary syndrome patients to reduce further risk of bleeding.1,2 DAPT de-escalation strategies have been investigated in several clinical studies, but the data remain limited and conflicting;3-5 therefore, current clinical practice guidelines provide no clear recommendations on de-escalation of P2Y12 inhibitors.6,7 The aim of the current study was to examine the effect of de-escalation of P2Y12 inhibitor in DAPT on cardiovascular events and bleeding complications after acute myocardial infarction (AMI) in patients undergoing percutaneous coronary intervention (PCI).
Using a nationwide database in Taiwan between July 1st 2013 and December 31st 2015, (ticagrelor was first approved by the National Health Insurance (NHI) Administration of Taiwan after July 1st 2013), the authors retrospectively evaluated patients who had received PCI during AMI hospitalisation and were initially on aspirin and ticagrelor and without adverse events at 3 months. The main outcome measurements included: 1) cardiovascular events: death and AMI readmission; 2) major bleeding events: gastrointestinal bleeding or other noncritical site bleeding that required transfusion of >2 U packed red blood cells, or intracerebral haemorrhage and other critical site bleeding leading to hospitalisation; 3) nonmajor clinically relevant bleeding: inpatient or outpatient visit for gastrointestinal and other noncritical site bleeding.
In total, 1,903 patients were identified as switched DAPT (to aspirin and clopidogrel) cohort and 4,059 patients as unswitched DAPT (continued on aspirin and ticagrelor) cohort. With a mean follow-up of 14 months, the incidence rates (per 100 person-year) of death and AMI readmission were 3.97 and 3.84 in the switched cohort and 1.83 and 2.23 in the unswitched cohort, respectively. An inverse probability of treatment weighted approach was used to balance baseline differences between the two groups. After adjustment for clinical variables, the switched cohort had a higher risk of death (adjusted hazard ratio [aHR] 2.18; 95% confidence interval [CI]: 1.62–2.93; p<0.001) and AMI readmission (aHR] 1.72; 95% CI: 1.27–2.34) compared with the unswitched cohort. When compared to the risk of bleeding complications, there was no significant difference between the two groups. In patients aged ≥65 years, the risk of death and AMI readmission in the switched group were still higher than that in the unswitched group (aHR 3.30; 95% CI: 2.19–4.98, aHR 2.40; 95% CI: 1.50–3.82, respectively).
There is a possibility that unguided de-escalation of P2Y12 inhibitor in DAPT is associated with a higher risk of death and AMI readmission in Taiwanese patients with AMI undergoing PCI. The caution surrounding unguided DAPT de-escalation is justified by the findings of this study and is reflected in real-world practice.