Frequency Domain-optical Coherence Tomography of Coronary Arteries Using a Diluted Iodinated Contrast-saline Mix with 5-Fr Guide Catheters

Background Optical coherence tomography (OCT) is currently mostly performed using 6-Fr coronary guide catheters via femoral access. Catheters with such large internal diameters are necessary to deliver viscous contrast media and achieve sufficient red blood cell washout. Currently, undiluted iodinated contrast media (15 mL/injection) is used to clear the coronary arteries of red blood cells (RBCs). This leads to an increase in the total amount of contrast used and often the need for femoral artery access. Our objective is to assess the feasibility of performance of OCT using a 5-Fr guide catheter via radial access using diluted iodinated contrast. Methods We present a case series of 11 patients where second-generation frequency domain (FD)-OCT was used to assess the coronary arteries using a novel 70:30 dilution mixture of iodinated contrast medium with heparinized normal saline. All procedures were performed with a 5-Fr coronary guide catheter via the radial artery approach. Results All procedures were successfully performed vial radial access with good quality imaging obtained. The target vessel was the left anterior descending artery in eight patients, the right coronary artery in two patients, and the left main coronary artery in one patient. OCT resulted in a change in management in 7/11 (64%) patients; no complications were reported with OCT. On average, 10 mL of contrast was used per injection. Conclusions The current study demonstrates the feasibility of FD-OCT using 5-Fr guide catheters and diluted iodinated contrast media. This approach lowers contrast exposure and potentially decreases vascular complications without sacrificing image quality.