Randomized Comparison of Strut Coverage between Ticagrelor and Clopidogrel in Acute Myocardial Infarction at 3-Month Optical Coherence Tomography

Abstract

PurposeThis study aimed to compare the effects of ticagrelor and clopidogrel on early neointimal healing assessed with optical coherence tomography (OCT) after drug-eluting stent (DES) implantation in patients with acute myocardial infarction (AMI).Materials and MethodsAMI patients were randomly assigned to either the ticagrelor or clopidogrel arm. After DES implantation, OCT was performed to assess the percentages of uncovered struts immediately after procedure and 3 months later.ResultsDue to early termination, 83 patients out of 106 initially enrolled patients (24% of planned participants) underwent 3-month OCT. Differences in vascular healing patterns between the two groups, including percentage of uncovered struts on 3-month OCT (9.6% vs. 11.7% in ticagrelor vs. clopidogrel, respectively; p=0.867), neointimal thickness, percentage of malapposed struts, and healing scores did not reach statistical significance. The predictors of uncovered strut on 3-month OCT included greater reference vessel diameter [odds ratio (OR)=1.96, p<0.001] and more malapposed struts (OR=1.12, p=0.003).ConclusionThe current study did not explore favorable effect of ticagrelor on 3-month vascular healing after DES implantation. Our findings should only be considered for generating hypothesis, due to insufficient power.

Differential Vascular Responses to New-Generation Drug-Eluting Stenting According to Clinical Presentation: Three-Month Optical Coherence Tomographic Study

“…This study included 2 randomized OCT trials using new-generation DES: Determination of the Duration of the Dual Antiplatelet Therapy by the Degree of the Coverage of the Struts on Optical Coherence Tomography From the Randomized Comparison Between Everolimus- Versus Biolimus-Eluting Stent (DETECT-OCT; NCT01752894) and Ticagrelor and Clopidogrel in Acute Myocardial Infarction at 3-Month Optical Coherence Tomography (TICA-OCT; NCT02037412). 7,8 Details of these studies are provided in the Supplementary Methods and Supplementary Table 1.…”

“…An uncovered stent was defined as a stent having any uncovered strut, and a significantly uncovered stent was defined when the percentage of the uncovered strut >6.0% on 3-month OCT. 9 A malapposed strut was defined as a strut that had detached from the vessel wall by ≥90 µm for Orsiro sirolimus-eluting stents, ≥100 µm for Xience everolimus-eluting stents, and ≥130 µm for Nobori biolimus-eluting stents, considering the stent strut thickness. 7,8 Stent malapposition (SM) was defined as a stent having any malapposed strut on OCT and classified into persistent, resolved, and late acquired by matching the images of postprocedural and 3-month follow-up OCT. 10 Significant SM was defined as a stent that had a strut with maximal wall-to-strut distance of ≥200 μm. 11 Changes (Δ) of OCT parameters were calculated as the values at postprocedure minus the values at 3 months.…”

“…Inter- and intraobserver variability in measurements of distances and areas on OCT was provided in previous studies. 7,8 All statistical analyses were performed with R Statistical Software (version 3.3.2; R Foundation for Statistical Computing, Vienna, Austria). A 2-sided P < .05 was considered significant.…”

Endpoint selection for noninferiority percutaneous coronary intervention trials: a methodological description

“…Since OCT endpoints are not the focus of this review, only a brief excursion is intended to illuminate this surrogate endpoint which is increasingly being used. [39][40][41][42][43] Three different criteria for a 'covered stent strut', namely >0 µm, >10 µm and >20 µm (Table 4) have been reported in the literature.…”

“…Chevalier and colleagues, Kim and colleagues, and Suwannasom and colleagues used the criterion of >0 µm strut coverage with a 3-month follow-up. [39][40][41] Yano and colleagues proposed a >10 µm cut-off value, 42 whereas Koppara and colleagues utilized the criterion of >20 µm. 43 Figure 5 reveals that, for strut coverage rates of 85% in the control group and, for example, 90% in the treatment group, 32 patients are necessary to detect a differences in stent coverage rates (power = 90%, SD = 6%).…”