Orbital atherectomy improved long-term outcomes in high-risk patients

LAS VEGAS — Patients with severely calcified arteries who underwent coronary orbital atherectomy had reduced risks for MI, death and repeat procedures at 1 year, according to new data from the ORBIT II study.

The prospective, multicenter, single-arm study included 443 patients with severely calcified lesions who underwent orbital atherectomy with the Diamondback 360 Coronary Orbital Atherectomy System (Cardiovascular Systems Inc.) to modify and prepare the lesions before stent placement.

The system was approved by the FDA in October. It features a diamond-coated crown that simultaneously rotates and orbits to sand down calcified lesions into miniscule particles.

All patients had severe calcification, as indicated by fluoroscopic or IVUS evidence. The ORBIT II study is the first to exclusively assess lesions of this type and the first to also include high-risk patients, such as those with left ventricular ejection fraction >25% or on dialysis, according to the researchers.

Data on major adverse cardiac events and cost were presented during the late-breaking clinical trial session at the Society for Cardiovascular Angiography and Interventions Scientific Sessions.

The Diamondback 360 Orbital Atherectomy System had high efficacy rates, with successful stent delivery in 97.7% of cases and less than 50% residual stenosis in 98.6% of cases.

Previously reported 30-day results indicated that major adverse cardiac events occurred in 10.4% of cases, with cardiac death in 0.2%, target vessel revascularization in 1.4% and MI in 9.7%. According to the new results, the rate of TVR/target lesion revascularization at 1 year was 5.9%, the rate of TVR was 1.9% and the rate of TLR was 4.7%. The rate of freedom from cardiac death at 1 year was 97% and freedom from major adverse cardiac events was 83.6%. No further incidences of MI occurred between 30 days and 1 year. Only history of CABG was identified as a significant predictor of major adverse cardiac events at 1 year (OR=1.89; 95% CI, 1.1-3.26).

The researchers also performed a cost analysis to compare patients aged 65 years or older enrolled in the ORBIT II study (n=297) with a matched Medicare sample of coronary stent recipients of the same age (n=308). Cost analysis including both inpatient and outpatient procedures demonstrated a mean reduction of $3,198 among older participants in ORBIT II compared with the Medicare sample. Adjustment for confounders including age, sex and comorbidities yielded a 17% reduction in mean cost in the orbital atherectomy group, or approximately $2,600 to $2,700 lower (P<.001).

Jeffrey Chambers

During the late-breaking clinical trials presentation, Jeffrey Chambers, MD, FSCAI, director of the cardiac catheterization laboratory at Mercy Hospital, Minneapolis, noted that rates of major adverse cardiac events, all-cause mortality and TLR observed in the ORBIT II trial at 9 months to 1 year were lower than rates observed in other trials that assessed patients with moderately to severely calcified lesions, such as ROTAXUS and ACUITY/HORIZONS.

“The Diamondback 360 Coronary Orbital Atherectomy System is the first FDA-approved novel technology to treat severely calcified lesions,” Chambers said. “At 1 year, the ORBIT II trial demonstrated lower [major adverse cardiac events] rates, and particularly lower target lesion revascularization, compared to literature. … Using the Diamondback 360 Coronary Orbital Atherectomy System as a lesion preparation tool prior to stent implantation for severely calcified coronary lesions is a new treatment option, with potential cost-saving benefits.” – by Adam Taliercio

For more information:

Chambers J. Late-breaking clinical trials. Presented at: the Society for Cardiovascular Angiography and Interventions Scientific Sessions; May 28-31, 2014; Las Vegas.

Disclosure: Researchers reported receiving consulting fees/honoraria from Cardiovascular Systems Inc.