Author + information
- Patrick C. Magnus1,
- John E. Jayne1,
- Hector M. Garcia-Garcia2,
- Michael Swart3,
- Gerrit-Anne van Es4,
- Jan Tijssen3 and
- Aaron V. Kaplan1
Intravascular ultrasound (IVUS) is well established and validated in the evaluation of coronary stents. However, for the practicing interventionalist (PI) without core lab expertise, the utility of IVUS is often limited by difficulty interpreting images. Frequency Domain-Optical Coherence Tomography (OCT) is a new intra-coronary imaging modality, which is now readily available to cath labs in the U.S. and Europe. OCT yields higher image resolution compared with IVUS. However, the consistency and accuracy with which PI’s interpret OCT images has not been fully evaluated or compared with IVUS.
We hypothesized that, compared with IVUS, PI’s experienced with both imaging techniques would interpret OCT images with less inter-observer variability and less deviation from core lab readings in the assessment of deployed coronary stents.
Following stent placement in consecutive patients meeting inclusion criteria, we performed both OCT and IVUS imaging of the stented segment using automated pullbacks. Image sets were screened by the core lab, and those determined to be adequate quality were then reviewed by PI’s from both academic and non-academic practices. The PI’s assessed stent expansion and symmetry, reference vessel and in-stent cross-sectional area (CSA) and diameter, and stent strut apposition. Their image interpretations were then compared to core lab readings and examined for inter-observer variability.
OCT and IVUS image sets (n=5) were reviewed by PI’s (n=11). Variation in the deviation from core lab measurement of in-stent CSA for IVUS was 1.48 mm2 compared with 0.87 mm2 for OCT (p = 0.042). Similarly, in assessment of reference vessel CSA, these values were 2.37 mm2 and 1.28 mm2 for IVUS and OCT respectively (p = 0.022). Among the PI reviewers, inter-observer variability (standard deviation of the mean readings) for measurement of in-stent CSA was 1.34 mm2 using IVUS compared with 0.85 mm2 using OCT (p = 0.024); for measurement of average reference vessel CSA this variability using IVUS was 2.31 mm2 compared with 0.91 mm2 using OCT (p =0.016).
Compared to IVUS, PI’s interpretation of OCT images have less variation and more closely reflect core lab evaluation.