Background and Objectives: Contemporary high-resolution intracoronary optical coherence tomography (OCT) requires injection of flushing media for image acquisition to avoid signal attenuation by red blood cells. There is a growing need for an alternative flushing media other than iodine contrast to reduce the risk of renal dysfunction. To address this issue, we investigated the safety and feasibility of pentastarch (hydroxyethyl starch) solution as a flushing media for OCT image acquisition and compared with the contrast media flushed images.

Materials and Methods: We prospectively enrolled 25 patients with 39 coronary lesions (26 stented lesions and 13 pre-stented or non-culprit lesions). Paired OCT images were obtained by manual injection of iodine contrast (average 12 mL), followed by pentastarch (average 15 mL). A total of 45 image runs were analyzed and each OCT pullback was assessed on a frame-by-frame basis by automated customized pixel-wise comparison algorithm. The number of clear image segments (CIS) and pre-specified quantitative measurements were compared between the paired OCT images.

Results: Image quality as assessed by proportion of CIS showed no significant difference between the contrast media and pentastarch (98.4% vs. 97.6%; p=0.846). Pixel-wise blood flushing capability correlated well between the paired image segments (p<0.001; Figure). Quantitative measurements of minimal stent area (7.24 ± 0.85 vs. 7.19 ± 0.74; p=0.769), minimal lumen area (3.15 ± 0.54 vs. 3.11 ± 0.49; p=0.716) showed no significant difference between the paired OCT runs. There were no clinically relevant complications associated with OCT imaging with pentastarch administration such as anaphylactic reaction, life-threatening arrhythmia, heart failure, or acute renal deterioration.

Conclusions: Intracoronary OCT using pentastarch is safe and technically feasible without affecting the optical signal intensity and overall image quality. Non-contrast imaging with pentastarch significantly reduces the obligatory iodine contrast load, therefore, could be considered as a promising strategy in high-risk patients for renal impairment.