Abstract Body (Do not enter title and authors here): Background: Intracoronary optical coherence tomography (OCT) is widely utilized for high-resolution imaging of coronary arteries, but it requiring contrast agents to displace blood from the imaging field. Accordingly, concerns have arose regarding the potential adverse effects of an additional use of contrast medium particularly in patients with renal dysfunction and heart failure, which may limit the widespread use of OCT.
Research Qustions: This study evaluates the feasibility and safety of isotonic electrolyte solution, lactated Ringer’s solution (LRS), as a flushing medium for a novel fast-pullback, high-frequency optical coherence tomography imaging system (HF-OCT, Gentuity, Sudbury, MA).
Methods: This prospective study enrolled 21 patients with stable coronary artery disease (CAD), and 52 pairs of OCT imaging were evaluated. HF-OCT imaging was sequentially performed using either a contrast agent (iohexol 350, group C) or LRS (group LRS) as the flushing medium. To evaluate the efficacy of blood clearance, clear imaging length (CIL) index was used, which was defined as the segment with a visible lumen-to-vessel wall boundary over at least 270 degrees. Quantitative and qualitative OCT image analyses were also compared between the two groups.
Results: The success rate of the first OCT imaging was 98.1% in group C, and 92.3% in group LRS. The injection volume used in each imaging was 5.0 +/- 0ml in group C and 18.9+/-1.5 ml in group LRS, respctively (p<0.05). CIL (mm) and CIL (%) were similar between the two groups (median 81.0 mm, interquartile range (IQR) 74.5-92.0 vs. median 79.2 mm, IQR 68.8-89.6, p=0.526 and median 100%, IQR 100-100 vs. median 100, IQR 99-100, respectively). Quantitative OCT parameters, i.e., minimum lumen area and diameter, were comparable between groups (median 2.75 smm, IQR 1.85-4.48, vs. 2.85 mms, IQR 2.03-4.58, p=0.654, and median 1.85 mm, IQR 1.53-2.40, vs. 1.90 mm, IQR 1.60-2.40, p=0.651, respectively). Qualitative OCT findings, such as presence of a lipid-rich plaque, thin-cap fibroatheroma, and macrophages, were equally visualized using both flushing media. No adverse events during imaging was observed in both groups.
Conclusions: HF-OCT imaging using isotonic electrolyte solusion (LRS) as a flushing medium is safe and effective, while maintaining comparable lesion assessment to contrast-based OCT imaging. This technique may be beneficial for the OCT-guided PCI in wide-range of CAD patients including renal dysfunction.