Prevalence and Clinical Impact of Tissue Protrusion After Stent Implantation: An ADAPT-DES Intravascular Ultrasound Substudy

The aim of this study was to evaluate the prevalence and long-term clinical impact of tissue protrusion (TP) after stent implantation.Stent implantation may be associated with tissue (plaque or thrombus) protrusion, especially in unstable lesions, but its clinical impact is unknown.ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) was a prospective multicenter study of 8,663 patients undergoing percutaneous coronary intervention (PCI) using drug-eluting stents. In a pre-specified intravascular ultrasound (IVUS) substudy, 2,072 patients with 2,446 culprit lesions underwent post-PCI IVUS (among whom some also underwent pre-PCI IVUS) and were classified according to the presence or absence of post-stent TP.After PCI, 34.3% of lesions displayed TP on IVUS. Median maximum TP was 0.7 mm(2) (interquartile range: 0.5 to 1.2 mm(2)) in area and 3.0 mm (interquartile range: 1.4 to 6.7 mm) in length. Patients with TP more often presented with ST-segment elevation myocardial infarction or non-ST-segment elevation myocardial infarction but less often with unstable angina or stable ischemic heart disease. In 893 culprit lesions that were also examined pre-PCI, TP was associated with larger reference luminal area, greater plaque burden, and more plaque ruptures, attenuated plaque, and virtual histology thin-cap fibroatheromas. Because a larger stent or post-dilation balloon was used, post-PCI luminal area was significantly larger in lesions with versus without TP. At 2-year follow-up, there was less clinically driven target lesion revascularization in lesions with TP and no significant difference in major adverse cardiac events (defined as cardiac death, myocardial infarction, or stent thrombosis) in patients with versus without TP.IVUS-detected TP after drug-eluting stent implantation was not associated with worse long-term clinical outcomes, in part because of greater stent expansion in lesions with TP.