Novel Atherectomy System Helps Treat Severely Calcified Lesions

SAN FRANCISCO, CA—A novel atherectomy system that “sands away” hard plaque components may help patients with severely calcified lesions. Results of the ORBIT II trial were presented March 9, 2013, at the American College of Cardiology/i2 Scientific Session.

Researchers led by Jeff Chambers, MD, of the Metropolitan Heart and Vascular Institute (Minneapolis, MN), looked at 443 patients with severely calcified coronary lesions who received treatment with the Diamondback 360º Orbital Atherectomy System (Cardiovascular Systems, St. Paul, MN) at 49 US sites.

The Diamondback system uses a rotating, eccentric diamond-coated crown to sand the hard components of plaque, leaving the soft components of plaque and tissue untouched.

Safety, Efficacy Exceed Goals

At 30 days, the primary safety endpoint of freedom from MACE (CK-MB > 3 times ULN, TVR, cardiac death) was 89.8%, above the performance goal of 83% (95% CI 87% to 92.7%). Individual component endpoints were:

  • MI: 9.7% (Non Q-wave 8.8%, Q-wave 0.9%)
  • TVR: 0.7%
  • TLR: 0.7%
  • Cardiac death: 0.2%

The primary efficacy endpoint of procedural success was 89.1%, exceeding the performance goal of 82% (95% CI 85.8% to 91.8%). Individual component endpoints were:

  • Successful stent delivery: 97.7%
  • Less than 50% residual stenosis: 98.6%
  • In-hospital MACE: 9.5%
    o   MI: 9.3%
    o   TVR: 0.7%
    o   Cardiac death: 0.2%

Dr. Chambers noted a decrease in MACE compared with historical controls. “The improvement in clinical outcome might be attributed to the unique mechanism of action of [the orbital atherectomy system],” he said. “It’s a technology that may address an unmet treatment need for this difficult to treat patient population.”

Dr. Chambers related a number of common complications with calcified lesions, including dissection during angioplasty or predilatation, difficulty achieving complete dilation, inadequate stent expansion, and inability to deliver a stent to the desired location.

He added that the orbiting crown of the Diamondback system enables continuous flow of blood and saline, minimizing thermal injury and potentially decreasing no reflow and periprocedural cardiac enzyme elevation. One crown treats different vessel diameters based on orbiting speed. The device uses a 0.012-inch guidewire and is compatible with 6-Fr guiding catheters.

Study Details

For the study, target vessel reference diameter was required to be between 2.5 mm and 4.0 mm, with a target lesion that did not exceed 40 mm in length. Target vessels were required to have TIMI 3 flow at baseline, and the target lesion had to have fluoroscopic or IVUS evidence of severe calcium deposit at the lesion site based on the protocol definition. Severe calcium was defined as radiopacities noted without cardiac motion before contrast injection generally compromising both sides of the arterial lumen with calcium length at least 15 mm extending at least partially into the target lesion or presence of ≥ 270° of calcium at 1 cross section via IVUS.

 

 


Source:
Chambers J. Pivotal trial to evaluate the safety and efficacy of the Diamondback 360° orbital atherectomy system in treating de novo, severely calcified coronary lesions (ORBIT II).
Presented at: American College of Cardiology Scientific Session; March 9, 2013; San Francisco, CA.

 

Disclosure:

  • Dr. Chambers reports serving on the speaker’s bureau for Cardiovascular Systems and having an ownership/partnership/principal stake in Vascular Solutions.

 

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