Cumulative MACE rate was 15.2% at 24-month and 18.2 % at 36-month follow-ups. Historically, when balloon angioplasty and stents are used to treat these lesions there have been MACE rates ranging from 11% to 15.8% at 15 months [4]. It is difficult to compare the MACE rates in the ORBIT I trial, since it was

a small, non-consecutive study. However, the results are less than the MACE rates reported in the few DES trials that have included moderate and severely calcified lesion [21] and [22]. As described above, one of the limitations in stent trials is that patients with calcified lesions were excluded while the ORBIT I trial specifically studied patients with calcified see more coronary arteries. The treatment associated with these challenging calcified lesions often leads to increased

MACE rates. As demonstrated by the ROTAXUS study, the MACE rate for calcified lesions treated with rotational atherectomy and DES was approximately 24% at 9 months [23]. In contrast, the ORBIT I trial demonstrated that patients with calcified coronary artery lesions treated with OAS and stent placement had a reduction in diameter stenosis and lower rate of MACE rates (9.1% at 30 days, 12.1% at 6 months, 15.2% at 2 years and 18.2% at 3 years). The ORBIT I trial, a clinical pilot study, suggests that the OAS treatment may offer effective method to modify calcified coronary lesion compliance to facilitate optimal check details stent placement in these difficult-to-treat patients. Patient treatment with the OAS resulted in a low cumulative MACE rate acutely and at 6, 12, 24 and 36-month follow-up time points. Future improvements in crown selection and operation technique should reduce acute complications that were observed in this first human feasibility study. A larger multi-center, pivotal trial has been completed in the United States to

evaluate OAS safety and efficacy in a larger patient population. This trial has several limitations. The trial was designed as a feasibility study and, therefore, lacked a control group for comparison. Additional limitations of ORBIT Rolziracetam I trial subset, are the small number of patients (33) treated with OAS at a single center. Core lab adjudication was lacking in this pilot study. The study protocol called for percent diameter stenosis to be calculated by IVUS during the index procedure. However, due to multiple difficulties experienced during pullback of the IVUS catheters, the IVUS core lab could not assess plaque volume and percent diameter stenosis for all 33 patients. These difficulties were due primarily to long lesion length and calcification, which contributed to the inability to insert the IVUS catheters and automate pullback. Therefore, plaque volume and percent diameter stenosis could not be calculated. As with any new technology, a learning curve is present. Additional experience may reduce the incidence of intraprocedural complications.