OBJECTIVES

: Beta blocker is a common medication for treatment of coronary artery diseases. Cytochrome P450 2D6 (CYP2D6) is involved in the metabolism of two cardiovascular drug classes including anti-hypertensives and anti-arrhythmics, but the influence of its polymorphisms on post-angioplasty patients with beta blocker treatment is not known.

METHODS

: We retrospectively analyzed patients who have undergone percutaneous coronary intervention (PCI) in our institution between December 2003 and December 2016. Clinical outcomes including myocardial infarction (MI) and major adverse cardiovascular events (MACE, including mortality, myocardial infarction, stroke and unplanned target vessel revascularization) up to 1 year post-angioplasty were compared between beta blocker users and non-users. Buccal swab was obtained from each patient for genotyping CYP2D6*1,*2,*5,*10,*36,*41 polymorphisms with iGene Cardiovascular Panel (Prenetics Inc., Hong Kong).

RESULTS

: Of 99 patients (67.8±10.2years, 75.8% male), 81.8% were beta-blocker users. 51.9% of these beta blocker users had started the prescription before PCI while 88.9% of them were still on beta blocker after 1 year. Further comparison according to their CYP2D6 phenotypes, i.e. extensive metabolizer (EM) (n=47) vs intermediate metabolizer (IM) (n=34), IM group has a higher incidence of MI than EM group (38.2% vs 14.9%, p=0.01) with an odds ratio 3.54 (95% CI: 1.23-10.21, p=0.02). The mean MI-free survival times in IM and EM groups were 10.1 and 11.4 months with a statistically significant difference (p=0.01), respectively. Overall, no significant difference on MACE incidence was shown between 2 groups (47.1% vs 40.4%, p=0.74).

CONCLUSIONS

: Patients on beta blockers after PCI with CY2D6 genetic variants causing decreased function were found to have a significant association with increased myocardial infarction. Data from a larger cohort is necessary in establishing the potential interaction effect of CYP2D6 polymorphisms on the pharmacokinetics and pharmacodynamics of beta blocker.