Objective: In this study, we aimed to describe the immediate and long-term vascular effects of OAS in patients with peripheral arterial disease (PAD) and moderate to severely calcified lesions.
Background: Debulking the calcified atherosclerotic plaque with the orbital atherectomy system (OAS) can potentially enhance vessel compliance and increase the chance of reaching a desirable angioplasty result.
Methods: A total of 7 patients were evaluated both at baseline and at 6-month follow-up. Following a diagnostic peripheral angiogram, patients with significant SFA disease had a baseline intravascular optical coherence tomography (IV-OCT) and the lesion was treated with OAS. Repeat IV-OCT was performed after atherectomy and after drug-coated balloon, if used. Patients were also evaluated with angiography and IV-OCT imaging at their 6-month follow-up.
Results: The majority of tissue removed was fibrous tissue. During follow-up, luminal volume increased for 4 of the 7 patients from baseline to 6-month follow-up and decreased in 3 patients. On average there was a 6% increase of luminal volume (P<.01 compared with baseline). A recent virtual histology algorithm was used for automatic classification of IV-OCT images unaided by any reader. The algorithm used convolutional neural networks to identify regions as either calcium, fibrous, or lipid plaque, and it agreed with an expert reader 82% of the time.
Conclusion: To the best of our knowledge, the current report is the first to describe vascular effects of OAS in medial calcified lesions immediately after and at follow-up using IV-OCT in patients with severe PAD.
Keywords: calcification; optical coherence tomography; orbital atherectomy; peripheral artery disease; virtual histology.