Tissue Characterization After Drug-Eluting Stent Implantation Using Optical Coherence Tomography

Objective-To validate optical coherence tomography (OCT) imaging for assessment of vascular healing in a preclinical animal model and human autopsy cases and to translate the findings to the assessment of vascular healing after drugeluting stent implantation in clinical practice. Approach and Results-Drug-eluting and bare metal stents were imaged 28 and 42 days after implantation in atherosclerotic rabbits using OCT and simultaneously evaluated by histology. After coregistration with histology, gray-scale signal intensity (GSI) was measured for identified mature or immature neointimal tissue. Autopsy specimens were imaged with OCT and GSI values correlated with histology. Finally, prospective OCT imaging and GSI measurements were acquired in 10 patients undergoing follow-up 6 months after stenting with drug-eluting stents. Histopathologic and OCT morphometric analysis of implanted stents showed excellent correlation. Neointimal growth and vessel healing at 28 days in the animal model best correlated with human stented arteries at 6 months. In animal and human autopsy specimens, mature neointimal tissue consistently showed higher GSI values. Receiver operating characteristic curve analysis displayed high sensitivity and specificity for detection of mature neointima in animal (96% and 79%, respectively) and human autopsy (89% and 71%, respectively) data. In patients undergoing OCT follow-up 6 months after drug-eluting stent implantation, prospective GSI analysis revealed that a minimum of 27.7% of areas above stent struts represented mature neointima. Conclusions-Novel GSI analysis of OCT imaging data allows distinction between mature and immature neointimal tissue in animal models, autopsy specimens, and patients undergoing invasive surveillance in simple atherosclerotic lesions.