Frequency domain optical coherence tomography to assess non-ostial left main coronary artery.

Aims: The aim of this study was to assess the feasibility of unprotected non-ostial left main (LM) imaging by frequency domain optical coherence tomography (FD-OCT).
Methods and Results: We conducted a retrospective analysis of OCT studies performed to image lesions located in the non-ostial LM. OCT studies were analysed off-line to detect the number of artefact frames in the different LM/bifurcation segments. OCT cross-sectional images were used to assess area measures. OCT longitudinal reconstructions were used to obtain the LM length. Standard quantitative coronary angiography (QCA) was used as the reference methodology. A total of 54 patients with non-ostial LM disease entered the study. The mean number of LM artefact frames was 8±10, corresponding to 19% of the total number of LM frames analysed. The percentages of artefact frames differed significantly according to the segment analysed: 43.3% proximal LM, 11.4% mid LM and 2.1% distal LM, 2.0% ostial left anterior descending artery and 0% ostial left circumflex artery (p<0.0001). All LM OCT measurements were significantly correlated with QCA measurements.
Conclusions: The results of the present study show that FD-OCT assessment of non-ostial LM disease is feasible and may provide high-quality imaging. OCT assessment of distal LM is more efficient than that of the proximal LM segment.