Calcified coronary lesions are difficult to treat for several reasons. They are prone to dissection of the arterial wall and can prevent adequate stent expansion. They are also difficult to dilate completely [Cavusoglu E et al. Catheter Cardiovasc Interv 2004] and can preclude stent delivery to the desired location [Gilutz H et al. Catheter Cardiovasc Interv 2000]. These factors result in poor clinical outcomes, including higher major adverse cardiac events (MACEs) and angiographic complications.

Researchers of the Evaluate the Safety and Efficacy of OAS in Treating Severely Calcified Coronary Lesions trial [ORBIT II; NCT01092416], presented by Jeffrey Chambers, MD, Mercy Hospital, Minneapolis, Minnesota, USA, examined the safety and efficacy of the coronary Orbital Atherectomy System (OAS) to prepare de novo, severely calcified coronary lesions for enabling stent placement.

This prospective multicenter single-arm trial comprised 443 patients at 49 US sites. Inclusion criteria included fluoroscopic or intravascular ultrasound evidence of severe calcification in the target lesion, a target vessel reference diameter ≥ 2.5 mm and ≤ 4.0 mm, and target lesion length ≤ 40 mm. Almost 65% of the patients were male, and the mean age was 71.4 years. The efficacy end point was successful facilitation of stent deployment in severely calcified coronary lesions. Safety end points included cardiac death, target vessel revascularization, myocardial infarction, and MACE. The patients were followed for 1 year.

Stent implantation was successful in 97.7% of patients, with < 50% residual stenosis in 98.6% of patients. Low safety end point rates at 30 days and 1 year showed that the OAS was safe for treating de novo, severely calcified coronary lesions.

Univariate analysis showed that only a history of coronary artery bypass graft was associated with an increased risk of MACE at 1 year (odds ratio, 1.89; 95% CI, 1.10 to 3.26; p = .0214). Safety comparisons with the ROTAXUS trial [Abdel-Wahab M et al. JACC Cardiovasc Interv 2013] and the ACUITY and HORIZONS trials [Genereux P et al. J Am Coll Cardiol 2013] revealed lower rates of MACE, all-cause mortality, and target lesion revascularization in the ORBIT II trial [Chambers J, data on file at Cardiovascular Systems, Inc].

Based on both inpatient and outpatient procedures, mean costs were $3198 lower in ORBIT II patients compared with Medicare stent patients with calcified lesions (p = .003).

The Diamondback Coronary OAS is the first Food and Drug Administration–approved novel technology for treating patients with severely calcified coronary lesions. Dr. Chambers concluded that using the OAS for lesion preparation before stent implantation offers patients with severely calcified coronary lesions a new treatment option with potential cost benefits.