Aims The aim of this study was to understand the impact of optical coherence tomography
(OCT)-detected thin-cap ibroatheroma (TCFA) on clinical outcomes of diabetes mellitus
(DM) patients with fractional flow reserve (FFR)-negative lesions. Methods and results
COMBINE OCT-FFR study was a prospective, double-blind, international, natural history
study. After FFR assessment, and revascularization of FFR-positive lesions, patients
with >= 1 FFR-negative lesions (target lesions) were classified in two groups based
on the presence or absence of >= 1 TCFA lesion. The primary endpoint compared FFR-negative
TCFA-positive patients with FFR-negative TCFA-negative patients for a composite of
cardiac mortality, target vessel myocardial infarction, clinically driven target lesion
revascularization or unstable angina requiring hospitalization at 18 months. Among
550 patients enrolled, 390 (81%) patients had >= 1 FFR-negative lesions. Among FFR-negative
patients, 98 (25%) were TCFA positive and 292 (75%) were TCFA negative. The incidence
of the primary endpoint was 13.3% and 3.1% in TCFA-positive vs. TCFA-negative groups,
respectively (hazard ratio 4.65; 95% confidence interval, 1.99-10.89; P < 0.001).
The Cox regression multivariable analysis identified TCFA as the strongest predictor
of major adverse clinical events (MACE) (hazard ratio 5.12; 95% confidence interval
2.12-12.34; P < 0.001). Conclusions Among DM patients with >= 1 FFR-negative lesions,
TCFA-positive patients represented 25% of this population and were associated with
a five-fold higher rate of MACE despite the absence of ischaemia. This discrepancy
between the impact of vulnerable plaque and ischaemia on future adverse events may
represent a paradigm shift for coronary artery disease risk stratification in DM patients.
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