Optical Coherence Tomography of the Coronary Arteries

Abstract

Intravascular imaging, particularly optical coherence tomography, has brought significant improvement in diagnostic and therapeutical approaches to coronary artery disease and has offered superior high-resolution visualization of coronary arteries. The ability to obtain images of intramural and transmural coronary structures allows the study of the process of atherosclerosis, effect of therapies, mechanism of acute coronary syndrome and stent failure, and performance of new devices and enables the interventional cardiologist to optimize the effect of percutaneous coronary intervention. In this review, we provide the summary of the latest published data on clinical use of optical coherence tomography as well as practical algorithm for optical coherence tomography-guided percutaneous coronary intervention for daily interventional practice.

Keywords: PCI; atherosclerosis; coronary intervention; intravascular imaging; myocardial infarction; optical coherence tomography; stent optimization protocol.

Fig. 1

OCT image display. ( A ) Angiographic coregistration with highlighted stented segment (white lines) and white marker in the middle of the lumen marking the corresponding cross-sectional image. ( B ) Cross-sectional image with automatically measured lumen area and marked stent struts (white dots) on the luminal surface. ( C ) Lumen profile with automated measurements of minimal lumen area and proximal and distal reference area, mean diameter, area stenosis (AS), and length. ( D ) Longitudinal view with rendered stent, color-coded apposition markers, and side branches of the artery. OCT, optical coherence tomography.

Fig. 2

Common pathological lesions and findings. ( A ) Fibrous plaque with calcified nodule (white arrow). ( B ) 360-degree calcified plaque. ( C ) Highly attenuated and sharply delineated signal representing a lipid plaque (white arrow). ( D ) White thrombi containing lesion (white arrows). ( E ) Stent underexpansion with severe malapposition (asterisk). ( F ) Multiple stent prolapses after stenting (white arrows). ( G ) Stent malapposition (asterisk) with tear of the vessel surface with an abluminal cavity. ( H ) 65% stent restenosis as a result of neoatherosclerosis.

Fig. 3

Algorithm for OCT-guided stent optimization. DRS, distal reference segment; EEL, external elastic lamina; MSA, minimal stent area; NC, noncompliant; OCT, optical coherence tomography; PCI, percutaneous coronary intervention; PRS, proximal reference segment.

Fig. 4

Illustrative case of an OCT-guided PCI. (1) Visually 40% stenosis of LAD with positive hemodynamic fraction flow reserve measurement (FFR 0.80). Distal (1A), proximal (1C) reference segment, and minimal lumen area (1B) were identified and mean reference diameters were measured. The mean lumen diameter was calculated ([4.16 − 2.96]/2) as 3.55 mm. According to the algorithm, up rounded to the nearest stent size, the appropriate stent diameter would be 3.75 mm. Since the stent size of 3.75 mm was not available, the size of 3.50 mm was chosen instead. Due to calculated length between reference segments of 16.2 mm (1D), the length stent of 18 mm was selected. There were no lipid-rich plaques at the sites of reference segments. (2) Postinterventional OCT shows final result after implanting 3.5 × 18 mm DES at 16 atm and postdilatation with 3.75 × 8 mm balloon at 20 atm. The minimal stent area was detected with value of 8.65 mm ² ( A ) and residual area stenosis of 10.9% ( B ), thus meeting the criteria for target MSA > 4.5 mm ² . The achieved stent expansion was 95% ( C ).There was no tissue protrusion, no edge stent dissection, or malapposition ( D —coded as white stent struts). LAD, left anterior descending; OCT, optical coherence tomography; PCI, percutaneous coronary intervention.