The use of drug eluting stents (DES) used to treat coronary artery blockages is limited by poor healing of the stented area. This will require the combined use of blood thinners such as aspirin and clopidogrel (i.e. dual anti-platelet therapy (DAPT)) to prevent complications such as clot formation on the stent which may lead to a heart attack. Diabetic patients and those presenting with a heart attack at the time of stent placement are at increased risk for clot formation. However, little is known of the healing responses after stent placement 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 clot formation and potential bleeding from the blood thinners, thereby improving the long-term safety of DES.

Intracoronary optical frequency domain imaging (OFDI) is a novel high resolution invasive imaging technique that has the ability to evaluate stent healing at follow-up. Among the commercially available coated stents used in the U.S., the zotarolimus eluting stents (RESOLUTE Integrity, Medtronic, Minneapolis, MN) has demonstrated superior healing in both preclinical and clinical studies.

The purpose of this trial is to determine the healing responses of the RESOLUTE Integrity stent as detected by OFDI in patients with and without diabetes presenting with ACS. Specifically, in this observational study, the study team will investigate non-insulin dependent diabetics and non-diabetics in the setting of ACS and RESOLUTE Integrity stent placement.

The investigators hypothesize that healing responses in patients with non-insulin dependent diabetes will be similar to those without diabetes presenting with ACS and that a majority of patients will demonstrate complete healing as determined by OFDI measurements.

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.

Inclusion Criteria:

• Any patient requiring percutaneous transluminal coronary interventions (PTCI) for acute coronary syndrome (ACS) and meeting criteria (as determined by the performing physician) for Resolute Integrity stent placement.

Exclusion Criteria:

• ST segment elevation MI (STEMI)
• stable angina
• current or planned pregnancy (for women of childbearing age)
• treatment of > 2 lesions during the index hospitalization
• insulin dependent diabetic patients at the time of stent placement
• use of overlapping stents.

Individuals who consented to participate in the study and met all eligibility criteria.

Participants were followed for adverse events for 6 months after having the study procedure. Adverse events were followed until the event subsided or, in the case of permanent impairment, the event stabilized and the overall clinical outcome was ascertained.

Participants were instructed to notify the research physician of any adverse effects of treatment, including those that are anticipated with this treatment.

Due to low enrollment there were not enough participants to provide 80% power for the comparison between the study arms, therefore, statistical analyses were not performed.