Orbital Atherectomy Continues to Show Efficacy, Cost Savings at 2 Years for Severe Calcifications

A novel atherectomy device that sands severely calcified coronary artery lesions to facilitate stent placement continues to demonstrate good long-term clinical efficacy and safety, according to a study presented May 7, 2015, at the Society for Cardiovascular Angiography and Interventions Scientific Sessions in San Diego, CA. 

Patients have “good initial outcomes and durable 2-year results with potential cost savings benefits,” said lead investigator Jeffrey W. Chambers, MD, of Mercy Hospital (Minneapolis, MN), in a media briefing prior to the presentation of data from the nonrandomized, single-arm ORBIT II trial. 

In all, 443 patients (mean age 71.4 years; 64.6% men) with severely calcified lesions were treated with the Diamondback 360 Coronary Orbital Atherectomy System (Cardiovascular Systems; St. Paul, MN) at 49 US sites. The device, which was approved by the US Food and Drug Administration in October 2013 for use in severely calcified coronary arteries, consists of a rotating, diamond-coated crown that is used prior to stent placement to sand the hard components of plaque, leaving the soft components and tissue untouched. 

All patients had a target vessel reference diameter between 2.5 and 4.0 mm, with a target lesion that did not exceed 40 mm in length. Target lesions were required to show fluoroscopic or IVUS evidence of severe calcium deposit at the lesion site. Severe calcium was defined as radiopacities noted without cardiac motion before contrast injection compromising both sides of the arterial lumen with calcium length of at least 15 mm extending at least partially into the target lesion or presence of ≥ 270° of calcium at 1 cross section via IVUS. 

Steady, Low Event Rates Even in Diabetic Cohort

More than one-third of the population had diabetes, 14.7% had a history of CABG, and the mean preprocedural percent stenosis was 84.4%. 

At 2 years, the total MACE (MI, cardiac death, or TVR) rate was 19.4%, including the individual endpoints of: 

• MI: 10.9% (all events occurred in the first 30 days)
• Cardiac death: 4.3% 
• TVR: 8.1% 

There were also no differences in outcomes between diabetic and nondiabetic patients for MACE or its individual endpoints (table 1).

An economic analysis comparing patients from the trial with a similar group of Medicare patients who underwent standard treatment, suggest that from a facility or health-system perspective, the total of projected cost offsets over 1 year would result in an average potential savings of up to $4,913 per patient. 

Additionally, compared with similar subsets of patients with severe calcification from the ACUITY and HORIZONS-AMI trials, the cost per life-year gained with orbital atherectomy was $11,895, well below high-value thresholds of $50,000 per quality-adjusted life-year, he said. 

The potential savings, Dr. Chambers noted, would likely be the result of reductions in: 

• Procedural costs related to stent implantation
• Repeat revascularization in the 30 days following index hospitalization
• Repeat revascularization between 30 days and 1 year

Although there is no “large body of knowledge to look at the outcomes in patients with severely calcified lesions,” Dr. Chambers observed that the 2-year rate of MACE in ORBIT II is lower than the 1-year base rate of 19.9% seen in the ACUITY and HORIZONS-AMI historical comparators. Additionally, he said the ongoing MACE trial should provide a better real-world view of both outcomes and economics.

According to Dr. Chambers, average procedure time was 68 seconds and additional use of radiation and contrast did not diverge from standard procedures. 

“This is the first trial that really looks at the long-term benefit [of atherectomy], and with drug-eluting stents, our revascularization rates are very low compared to other lesions with severe calcium,” Dr. Chambers said. He added that compared with rotational atherectomy, the orbital device “treats a larger portion of the artery” and allows for fuller stent expansion, which ultimately provides a better long-term result. 

Atherectomy ‘Underused’

In a telephone interview with TCTMD, Ajay J. Kirtane, MD, SM, of Columbia University Medical Center (New York, NY), said that atherectomy to clear severe calcifications is likely underutilized and details on its long-term outcomes are much needed. 

“In the past it was underused because it was complicated, specific training was required, and there can be a significant rate of complications if you don’t do it right,” he said. “The bigger picture here is that increasing awareness of the importance of calcifications as a whole is a good thing, and [atherectomy] in general is something that interventionalists need to become more familiar with in their practices.” 

Dr. Kirtane said the lack of randomization in ORBIT II and the use of historical controls make it difficult to draw strong conclusions about the clinical or economic data. However, he said that the suggestion that use of an atherectomy device before PCI may prevent the need for repeat revascularizations is “compelling.” 

“Many of us have seen cases of repeat revascularizations that could, to a large extent, have been obviated had an atherectomy device been used up front or had optimal imaging been used to ensure the stent was expanded,” he said. “To whatever extent that we can make the PCI procedure optimized, especially given the very low complication rates, it’s going to be beneficial to patients. But at present, any comparisons regarding the various types of atherectomy devices are purely speculative.” 

Note: Co-author Philippe Généreux, MD, is a faculty member of the Cardiovascular Research Foundation, which owns and operates TCTMD. 

Source:

Chambers JW. Orbital atherectomy treatment of severely calcified coronary lesions: two year results of the ORBIT II trial and long-term economic analysis. Presented at: Society for Cardiovascular Angiography and Interventions Scientific Sessions; May 7, 2015; San Diego, CA.

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