Predominant microvessel proliferation in coronary stent restenotic tissue in patients with diabetes: Insights from optical coherence tomography image analysis

BackgroundCoronary optical coherence tomography (OCT) enables virtual depiction of histological findings of in-stent restenotic tissue. The aim of this study was to investigate the microvessel proliferation within in-stent restenotic tissue and the influence of diabetes mellitus (DM).MethodsWe examined 54 in-stent restenotic coronary artery lesions (stenotic area > 50%) from 50 consecutive patients including 28 with DM (56%) and 9 insulin-treated DM patients (18%); who underwent coronary time-domain OCT imaging with automatic pull back (1 mm/s, 20 frames/s). Microvessels were defined as low-signal cavities with a diameter of 50-150 microns and a trajectory parallel to the lumen recognized on 3 consecutive cross-sectional OCT image frames. The microvessel index was calculated as the number of frames with microvessel/total number of frames × 100. Patients were stratified into 3 groups: 1) without microvessels, 2) with a low (< median value) microvessel index, 3) with a high microvessel index.ResultsMicrovessels were detected in 566 frames (3.1%) from 26 lesions (48%) in 24 patients (48%). A greater incidence of DM and higher serum glucose levels were observed in the high microvessel index group (DM: 42% vs 58% vs 83%, p = 0.049; serum glucose level: 118.2 ± 44.6 vs 122.6 ± 31.0 vs 172.8 ± 63.1 mg/dL, p = 0.03 between low and high microvessel index group, p = 0.005 between no microvessel and high microvessel index group).ConclusionsMicrovessel formation may be a unique pathophysiological factor of in-stent restenoses in patients with DM.