Cardiovascular Systems announced that it has completed enrollment in Japan for its Coronary Orbital Atherectomy System Trial (COAST) study.

Taking place in both Japan and the US , the study is designed to assess the safety and efficacy, as well as economic outcomes, of CSI’s new investigational micro crown Orbital Atherectomy System (OAS) in treating severely calcified coronary lesions in patients suffering from Coronary Artery Disease (CAD).

COAST requires a minimum of 50 patients in the U.S. at up to 15 sites and a minimum of 25 patients across 5 sites in Japan for a total of 100 patients to be enrolled. CSI surpassed its required number of enrollments in Japan with a total of 26 patients on November 20, 2014. Enrollment in the United States is expected to be completed in 2015.

The 1.25 mm micro crown is CSI’s second-generation system designed to facilitate stent delivery in patients with severely calcified lesions who are acceptable candidates for percutaneous transluminal coronary angioplasty (PTCA) or stenting.

The micro crown OAS is designed to improve the tracking and piloting of the OAS driveshaft and the ability of the crown to reach the lesion while operating at lower rotational speeds.

"Completing international enrollment is a key milestone in our path to expanding successful OAS treatment of patients with severe CAD," said David L. Martin, CSI president and chief executive officer. "Data from this study is expected to help secure approval for the use of the new micro crown OAS in CAD patients in the world’s two largest coronary markets."

COAST builds on CSI’s ORBIT II study, the first trial designed to study patients with severely calcified lesions who are typically excluded from all major trials but commonly seen in the real world. It is a prospective, single-arm, multi-center, global, investigational study.

The 26 subjects were enrolled at five sites in Japan. The study’s principal investigators are Dr. Shigeru Saito, Director of Cardiology and Catheterization Laboratories at Shonan Kamakura General Hospital, Kamakura, Japan and Dr. Gregg Stone, Director of the Cardiovascular Research and Education Center for Interventional Vascular Therapy at Columbia University Medical Center, New York.

CAD is a life-threatening condition and leading cause of death in men and women in the United States. CAD occurs when a fatty material called plaque builds up on the walls of arteries that supply blood to the heart. The plaque buildup causes the arteries to harden and narrow (atherosclerosis), reducing blood flow.