Optical Frequency Domain Imaging (OFDI) and Vascular Healing After Stent Placement

The long-term efficacy of drug eluting stents (DES) used to treat symptomatic coronary artery disease is limited by incomplete healing of the stented segment necessitating the use of dual anti-platelet therapy (DAPT) with aspirin and a thienopyridine to prevent these late thrombotic complications. Diabetic patients and those presenting with acute coronary syndrome (ACS) at the time of DES placement are at increased risk for late in stent thrombosis, however, little is known of the healing responses in these populations. Currently all patients receiving DES are advised to complete DAPT for twelve months although more personalized durations of DAPT based on stent healing would reduce both thrombosis and bleeding, thereby improving the long-term safety of DES. Intracoronary optical frequency domain imaging (OFDI) is a novel high resolution invasive imaging modality with the potential to discern plaque morphology at stent placement and stent strut healing at follow-up. Among the commercially available coated stents used in the U.S., the zotarolimus eluting stents (RESOLUTE, Medtronic, Minneapolis, MN) has demonstrated superior endothelialization and long term safety data in both preclinical and clinical studies. The purpose of this trial is to determine the healing responses to the RESOLUTE stent as detected by OFDI in patients with and without diabetes presenting with ACS. Specifically, investigators will 1) determine while using OFDI whether any difference in healing occurs in non-insulin dependent diabetic patients presenting with ACS after RESOLUTE stent placement at 6 months; 2) determine how initial plaque morphology and angiographic measures such as late loss correlate with stent strut healing; and 3) examine whether selected biomarkers have an utility in predicting stent strut healing by OFDI. Investigators will conduct a clinical study that images subjects at baseline and at 6 months after stent placement with intracoronary OFDI. OFDI data will be utilized to determine plaque morphology prior to intervention, ensure adequate strut apposition and stent sizing immediately post deployment and to measure stent strut coverage at 6 month follow-up. Two follow-up imaging passes will be conducted to evaluate test-retest variability of the coverage measurement. In addition to assessing the feasibility of using the OFDI coverage metric in vivo, this data may provide information on the magnitude of coverage that can be expected at 6 months following RESOLUTE stents.