Two-Year ORBIT II Outcomes Published for CSI's Diamondback 360 OAS Device

April 29, 2016—Philippe Généreux MD, et al reported 2-year outcomes of the ORBIT II evaluation of the safety and efficacy of the Diamondback 360° coronary orbital atherectomy system (OAS; Cardiovascular Systems, Inc.) in treating severely calcified coronary lesions trial, with emphasis on the impact of stent type. The study was published online ahead of print in Catheterization and Cardiovascular Interventions (CCI).

The ORBIT II investigators concluded that OAS with the Diamondback 360 device remained safe and effective for patients with de novo, severely calcified lesions at 2 years. Additionally, they observed that adverse ischemic events were significantly higher with bare-metal stents (BMC) compared with drug-eluting stents (DES).

The data were first presented last May during a late-breaking clinical trial session at SCAI 2015, the Society for Cardiovascular Angiography and Interventions annual scientific sessions in San Diego, California. 

Dr. Chambers, et al also recently published findings supporting the device’s cost effectiveness for treating severely calcified coronary lesions of the Diamondback 360 in Therapeutic Advances in Cardiovascular Disease (2016;10:74-85).

As reported in CCI, the single-arm ORBIT II trial enrolled 443 patients with severely calcified lesions at 49 United States sites. All patients were intended to be treated with OAS before stent implantation. The primary safety endpoint was 30-day major adverse cardiac events (MACE: cardiac death, myocardial infarction, or target vessel revascularization). 

The ORBIT II investigators divided the patients into three groups, according to the type of stent implanted: BMS, first-generation DES, or second-generation DES. The 2-year MACE rate and its components were compared between the groups. 

Two-year data were available in 419 of 443 patients (94.6%), with a median follow-up time of 25.1 months. Stent-type data were available in 435 of the 443 patients (98.2%). Six patients received stents of more than one type and were excluded from the stent type comparisons. In the ORBIT II study cohort, the 2-year rates of MACE, cardiac death, and target vessel revascularization were 19.4%, 4.3%, and 8.1%, respectively.

Among the 429 patients included in the stent comparison analyses, 43 patients (10%) received BMS, 74 (17.2%) received first-generation DES, and 312 (72.7%) received second-generation DES. 

The investigators found that the 1- and 2-year target lesion revascularization rates were lower among patients receiving first-generation DES (1.4% and 6.3%) and second-generation DES (3.9% and 5%) compared to patients receiving BMS (15.3% and 15.3%), respectively. Higher diameter stenosis and the use of BMS were independently associated with the occurrence of MACE and TVR at 2 years, reported the investigators in CCI.

The Diamondback 360, which received US Food and Drug Administration approval in October 2013, has previously demonstrated favorable safety outcomes in hospital at 30 days and at 1 year. The 1-year safety and efficacy, as well as an economic analysis from ORBIT II were presented in a late-breaking presentation at the EuroPCR 2014 conference in Paris, France.