SCAI.15: Orbital atherectomy sustains its benefits at 2 years

An atherectomy device that “sands” calcified lesions in coronary arteries before stenting proved to be effective and durable at two years, and possibly even cost-effective, in a late-breaking clinical trial unveiled on May 7.

Jeffrey Chambers, MD, director of the Cardiac Catheterization Laboratory at Mercy Hospital in Minneapolis, presented the two-year results of ORBIT II at the Society for Cardiovascular Angiography and Interventions (SCAI) 2015 scientific sessions in San Diego. ORBIT II (Orbital Atherectomy Treatment of Severely Calcified Coronary Lesions) is a prospective, multicenter, single-arm trial that was designed to assess the safety and efficacy of the Diamondback 360 Orbital Atherectomy System (Cardiovascular Systems) to prepare severely calcified coronary lesions for stent placement.

“This is the first trial that looks at long-term benefit, and with drug-eluting stents our revascularization rates are very low compared to other lesions with severe calcium,” Chambers said at a press briefing.

The trial enrolled 443 patients at 49 sites in the U.S. who had severe calcification in the target lesion of at least 15 mm in length. Chambers presented one-year results at SCAI.14.  

Stents were delivered successfully in 97.7 percent of cases and 98.6 percent of patients had less than 50 percent residual stenosis. At one year, the cardiac death rate was 3 percent, the target vessel revascularization/target lesion revascularization rate was 5.9 percent and the major adverse cardiovascular event (MACE) rate was 16.4 percent.

That increased to 4.3 percent, 8.1 percent and 19.4 percent, respectively, at two years. In diabetic patients, the rates were 5.3 percent, 8.7 percent and 20.6 percent, respectively.

“We don’t have a large body of knowledge to look at patients with severely calcified lesions,” Chambers acknowledged. He cited another trial that reported a one-year MACE rate of 19.9 percent. “Our MACE rate at two years is less than their one-year MACE rate.”

He provided an update on an economic analysis at one year that expanded on 2014 results. Researchers used a code for calcification to compare 300 Medicare patients with the ORBIT II patients. In their latest analysis, they found in an average-case scenario a cost savings of about $4,000, which offset the $3,795 price tag for the device. The best-case scenario produced a cost savings of $1,118 at one year.

Using data from a subset of the ACUITY/HORIZON-AMI trials (Acute Catheterization and Urgent Intervention Triage Strategy/Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) as a comparator, they determined that the Orbital approach cost $11,895 per life-year gained, which put it within the accepted threshold for value.  

Chambers noted there is little comparative data to date. He proposed that this technique may be more successful than previous atherectomy devices because it orbits as well as rotates.

“It treats a larger portion of the artery,” he said. “I believe it does something to break up the sheets of calcium and that potentially allows larger stent expansion. Stent expansion is really what translates to good long-term results.”

The FDA approved the Diamondback atherectomy device in coronary arteries in 2013. The ORBIT II trial was funded by Cardiovascular Systems.