Prevalence of clOpidogrel ‘resIstaNce’ in a selected population of patients undergoing elective percutaneous coronary intervention at a tertiary cardiovascular centre in Trinidad: the POINT pilot study

Abstract

Objectives This novel, pilot study aimed to assess the estimated prevalence of high on-treatment platelet reactivity (HPR) in Trinidad and Tobago.MethodsPatients (n=40) who were awaiting elective percutaneous coronary intervention on maintenance dual antiplatelet therapy (DAPT) with aspirin 81 mg daily and clopidogrel 75 mg or loaded at least 48 hours prior were recruited. Platelet reactivity with the VerifyNow P2Y12 assay (Accriva Diagnostics, San Diego, California, USA) was assessed prior to cardiac catheterisation.Results60.7% (17/28) of the South Asian (Indo-Trinidadians) patients had HPR, whereas 14.3% (1/7) of Africans and 40% (2/5) of mixed ethnicity had HPR. There was a significant association between HPR (P2Y12 reaction units >208) and ethnicity with South Asians (Indo-Trinidadians) (OR 5.4; 95% CI 1.18 to 24.66, p=0.029).ConclusionsThis pilot study serves to introduce the preliminary observation that the estimated prevalence of HPR is considerably higher within the heterogeneous population in Trinidad at 50% as compared with predominantly Caucasian studies. Furthermore, the HPR is significantly higher in South Asians (Indo-Trinidadians) (>60% of patients) which has severe clinical repercussions considering the cardiovascular disease pandemic. Clopidogrel may not be a satisfactory or optimal antiplatelet agent in this subgroup, and therefore, another more potent antiplatelet such as ticagrelor should be used instead. Further large-scale studies are imperative to confirm these findings. (Funded by the University of the West Indies, St. Augustine; POINT ClinicalTrials.gov number, NCT03667066.)

The Effect of Low-Dose Ticagrelor on Platelet Function Profiles in Patients With Stable Coronary Artery Disease in Trinidad: The TWIST Pilot Study

“…Diabetes is implicated in accentuating platelet reactivity via a complex thrombotic milieu [ 5 ]. The study also had a relatively higher proportion of women (56%) as compared to prior studies performed by this group in a similar setting [ 6 , 10 ]. Thus, any emerging recommendations cannot be extrapolated to other populations, such as patients with ACS.…”

“…South Asians have higher proportional mortality rates from CAD compared with other Asian groups [ 21 ]. In a recent pilot study, the estimated prevalence of HPR was considerably higher at 50%, with HPR being more prevalent in the South Asian ethnicity [ 6 ]. To our knowledge, these novel regimens and doses remain untested in these ethnic minority subpopulations, such as Trinidad, and to a broader region, the Caribbean.…”

“…Thus, any emerging recommendations cannot be extrapolated to other populations, such as patients with ACS. The patient population constituted almost two-thirds of South Asians, whose ethnicity has also been linked with HPR [ 6 ]. These issues may suggest an inherent selection bias.…”

“…However, the pharmacodynamic (PD) effects of clopidogrel are heterogeneous and impacted by a multitude of genetic, drug interaction, and clinical factors, leading to a broad interindividual response [ 4 , 5 ]. A recent study performed by Seecheran et al in Trinidad demonstrated the estimated prevalence of high on-treatment platelet reactivity (HPR) to be considerably higher at 50%, even more so in the South Asian subpopulation at 60% [ 6 ]. Within the last decade, novel, more potent P2Y 12 inhibitors, such as ticagrelor, have gained traction as a preferred strategy to mitigate HPR [ 7 ].…”

“…A recent East Asian systematic review suggested that low-dose ticagrelor revealed an antiplatelet efficacy similar to that of standard-dose ticagrelor, which was faster and more potent than clopidogrel, however, required further evaluation in a large-scale randomized clinical trial [ 9 ]. These findings raised the question as to whether the current recommended dose of ticagrelor is suitable for the Trinidadian population, a population often described as multiethnic and cosmopolitan, comprising an admixture of South Asian, Caribbean Black, East Asian, Arabic, and Caucasian ancestries [ 6 , 10 ]. Therefore, we conducted this exploratory pilot study to assess the antiplatelet PD effect of low-dose ticagrelor in a Trinidadian subpopulation with stable coronary artery disease (CAD).…”