Aims: Recently, favourable procedural 30-day and one-year outcomes with the Diamondback 360 Orbital Atherectomy System (OAS) in the treatment of severely calcified lesions have been reported. The purpose of this study was to assess the therapeutic mechanism and efficacy of the OAS with optical coherence tomography (OCT) imaging.
Methods and results: This was an observational imaging study in 18 patients with complex calcified coronary artery lesions who underwent percutaneous coronary intervention with the OAS. Pre-OAS and post-OAS OCT analyses demonstrated that the minimum lumen area (MLA) increased from 2.07±0.66 mm2 to 2.38±0.68 mm2 with a lumen volume increase of 9.68±17.22 mm3 in the ablated segment with a length of 30.7±13.1 mm. The maximal vessel injury (dissection) involved the intima in 39% and the media in 6% of the study population. To eliminate the influence of post-OAS vasoconstriction, the ablation area was measured with the interpolated original lumen surface by comparing the endoluminal border of the pre-OAS image. The ablation area at the maximal ablated cross-section was 0.55±0.41 mm2, and the ablation volume by OAS was 2.68±2.80 mm3.
Conclusions: OAS effectively ablated coronary calcified tissue with some degree of intimal dissection. OCT imaging can be used to assess the total ablation volume after orbital atherectomy.