Study Highlights Mechanical Effects of CSI's Diamondback 360 OAS in Heavily Calcified Lesions

May 19, 2015—Cardiovascular Systems, Inc. (CSI) announced that Annapoorna S. Kini, MD, et al published a study on the mechanical effect of orbital atherectomy (OA) and rotational atherectomy (RA) in treating heavily calcified coronary lesions. The study is available online in the Journal of Catheterization and Cardiovascular Interventions.

The study evaluated CSI’s percutaneous Diamondback 360 orbital atherectomy system (OAS), which is indicated to facilitate stent delivery in patients with coronary artery disease who are acceptable candidates for percutaneous transluminal coronary angioplasty or stenting due to de novo, severely calcified coronary artery lesions. The US Food and Drug Administration granted 510(k) clearance for the use of the Diamondback 360 OAS in coronary arteries in October 2013 and in treating peripheral arteries in August 2007.

The study was led by Dr. Kini, who is Professor of Cardiology at the Mount Sinai Hospital and Icahn School of Medicine and Director of the cardiac catheterization lab at Mount Sinai Hospital in New York, New York.

In the company’s press release, study co-investigator Samin K. Sharma, MD, Director of Clinical and Interventional Cardiology at The Mount Sinai Medical Center, commented, “We found that using OA versus RA to treat heavily calcified coronary lesions resulted in more significant tissue modification leading to better stent apposition and expansion. This may translate to lower major adverse cardiac event and restenosis rates.”

According to the company, Dr. Kini’s study sought to assess the mechanical effects of RA and OA on heavily calcified coronary lesions and subsequent stent placement using optical coherence tomography (OCT). The retrospective analysis included 20 consecutive patients who were treated with either RA or OA. CSI noted that although small case reports have described the mechanistic effect of RA in calcified coronary lesions, there has been no imaging study to assess the effect of OA on coronary artery architecture and/or compare the effects of two atherectomy devices.

This study analyzed 20 consecutive patients with OCT imaging performed after atherectomy and after stent implantation (RA, n = 10; OA, n = 10). Postatherectomy OCT analysis identified tissue modification with deep dissections in approximately one-third of lesions after RA and OA; however, post-OA dissections (“lacunae”) were significantly deeper (1.14 vs 0.82 mm; P = .048). Post-OA/RA lesions with dissections had a significantly higher percentage of lipid-rich plaques and smaller calcification arcs as compared to plaques without dissections. Stents after OA were associated with a significantly lower percentage of stent strut malapposition than post-RA stents (4.36% vs 8.02%; P = .038).

The investigators concluded that although the incidence of dissections was comparable between RA and OA cases, OA resulted in deeper tissue modifications (lacunae), as shown by OCT imaging. The finding might provide an explanation for a better stent apposition after OA as compared to RA. Their impact on long-term outcome needs to be determined, noted the investigators.

Noting that these results demonstrated that OA delivers less stent malaposition and better stent placement and expansion, CSI also advised that the company’s ORBIT II study results showed successful stent delivery in 98% of the procedures, with 96% freedom from severe angiographic complications post-OA. ORBIT II’s 2-year results also showed a 94% freedom from target lesion revascularization and 81% freedom from major adverse cardiac events. The ORBIT II 2-year data were presented on May 7 at the Society for Cardiovascular Angiography and Interventions’ 2015 scientific sessions held on May 6–9 in San Diego, California.