Procedural and Long-Term Ischemic Outcomes of Tight Subtotal Occlusions Treated with Orbital Atherectomy: An ORBIT II Subanalysis.

BACKGROUND/PURPOSE: Orbital atherectomy is an effective treatment strategy to modify severely calcified coronary lesions prior to stent placement. Traversing a severely calcified subtotal occlusion with the crown may be more challenging compared with a less severely stenotic lesion. The purpose of this ORBIT II subanalysis was to evaluate outcomes post-orbital atherectomy (OA) treatment of lesions with ≥95% stenosis. METHODS/MATERIALS: ORBIT II, a single-arm, prospective, multicenter trial, enrolled 443 subjects with severely calcified coronary lesions. Patients with chronic total occlusions were excluded from the trial. Subjects with the OA device activated were stratified based on pre-procedure percent stenosis: ≥95% stenosis (N = 91) and <95% stenosis (N = 341). Procedural success and 3-year major adverse cardiac event (MACE) rates were compared. RESULTS: The severe angiographic complications rates were 6.6% and 6.7% in the ≥95% and <95% stenosis groups, respectively. There was no significant difference in procedural success (94.5% vs. 88.3%, p = 0.120). 3-year MACE rates were similar (27.1% vs. 22.5%, p = 0.548), as were the rates of cardiac death (5.7% vs. 7.1%, p = 0.665) and MI (7.9% vs. 12.1%, p = 0.244). The TVR rate was higher in the ≥95% stenosis group (19.1% vs. 7.5%, p = 0.004). CONCLUSIONS: In ORBIT II, OA treatment of lesions with ≥95% stenosis resulted in a high rate of procedural success. Although the 3-year revascularization rate was higher in the ≥95% stenosis group, it is not unexpected given the challenge of treating such complex lesions. The results of this analysis suggest that OA may be a reasonable treatment strategy for tight, severely calcified subtotal occlusions. SUMMARY: The purpose of this ORBIT II subanalysis was to evaluate outcomes post-orbital atherectomy (OA) treatment of lesions with ≥95% stenosis. In ORBIT II, OA treatment of lesions with ≥95% stenosis resulted in a high rate of procedural success. Although the 3-year revascularization rate was higher in the ≥95% stenosis group, it is not unexpected given the challenge of treating such complex lesions. The results of this analysis suggest that OA may be a reasonable treatment strategy for tight, severely calcified subtotal occlusions.