Safety and efficacy of frequency domain optical coherence tomography in pigs

Aims: To determine the safety and efficacy of frequency domain OCT, which can scan at much higher rates and make it possible to avoid an occlusion balloon and image during an angiographic injection through guide catheter. The catheters have diameters ranging from 2.7 to 3.5 Fr. The presence of the imaging catheter increases fluid resistance to the injection of viscous solutions necessary for clearing the blood. Methods and results: The Volcano 3.5 Fr frequency domain OCT catheter system was investigated for safety in (a) n=10 porcine studies using acute and 30-day histology, and (b) for efficacy in n=9 in vivo porcine coronary arteries. We found: (a) frequency domain imaging is safe in the porcine model using histology as an endpoint; (b) the addition of a viscous contrast (iodixonal) to saline is superior for lumen clearance compared to saline alone; (c) hand injection, 4 ml/sec, and 6 ml/sec power injection all provided similar vessel wall clearance; (d) the anticipated loss of vessel wall visualisation with left main injection (due to half the injectate in the non-imaged vessel) was not evident in proximal and middle coronary artery OCT catheter positions. Conclusions: Frequency domain OCT is safe and efficacious in the porcine model.