The first patient has been enrolled in COMPLIANCE 360° clinical trial which is testing Cardiovascular Systems' (CSI; St. Paul, Minnesota) Diamondback 360° Peripheral Arterial System, a minimally invasive catheter for treating peripheral arterial disease (PAD), in lesions above the knee.

"We want to prove that our device, followed by a low-pressure balloon, is superior to putting in a balloon and a stent," Brian Doughty, VP of commercial operations, Cardiovascular Systems (CSI; St. Paul, Minnesota) told Medical Device Daily.

The 50-patient, five-center, prospective, randomized study will compare the benefits of first modifying calcified plaque with the Diamondback 360° system followed by low-pressure balloon inflation if needed, versus the use of high-pressure balloon angioplasty alone in calcified lesions above the knee. Those patients will then be followed for a year.

The Diamondback 360° received FDA 510(k) marketing clearance in August 2007 and, since then, 500 hospitals have adopted it, according to the company.

Typical treatment of vessels involves the use of high-pressure balloon angioplasty, which can damages large diseased vessels. Doughty said Diamondback 360° could reduce that level of balloon pressure required.

"If you start to get plaque in the arteries, it's soft and your vessel can still get larger and smaller to control blood pressure," Doughty said. "But if it gets hard, it's rigid. The Diamondback will only impact the fibrotic and calcified plaque so the physician doesn't have to decide if it's the plaque or the vessel. It will remove the hardest plaque first and leave any soft tissue alone."

The catheter is able to attack hard plaque but leave the soft tissues alone due to the tiny diamond particles on the rice-sized metal crown.

Doughty said it's analogous to a diamond ring: "If you have a diamond ring and run it across movable skin it does nothing; but if you move it across glass, it scratches and digs in. The same theory applies to the Diamondback."

"Two-thirds of the time, the compliance of the vessel is compromised if you put a balloon or stent in there," he said. "The balloon will distend the vessel or the vessel will recoil and causes damage. The Diamondback goes into something hard and makes it soft again. You can then put in a low pressure balloon and it causes no damage."

One arm of the study will include use of the device followed by any adjunctive therapy the physician deems appropriate, either low-pressure balloon angioplasty or balloon followed by a stent. The second arm will include use of a balloon followed by a stent.

"Our tool in doctors' hands has successfully treated more than 15,000 patients in less than two years since our FDA clearance," said CSI president/CEO David Martin. "COMPLIANCE 360° is the first of several post-market studies CSI is sponsoring to provide physicians with the clinical data they need. We plan to launch Calcium 360°, a study evaluating treatment with the Diamondback 360° in calcified lesions below the knee, in the coming months."

The Calcium 360° trial, set to enroll patients beginning in December, will be exactly the same as the COMPLIANCE 360° trial except that it will address vessels below the knee.

"Lower vessels are smaller and more likely to be calcified," Doughty said. "There's nothing in the literature to substantiate this, but experts will tell you that fibrotic or calcified vessels occur 30% of the time above the knee and 70% of the time below the knee."

CSI earlier this year closed its merger with Replidyne (Louisville, Colorado) and the company went public with stock trading on the Nasdaq Global Market under the symbol CSII. Through the transaction, an additional $37 million in net assets, primarily cash, became available to CSI's business (MDD, Feb. 27, 2009).

Doughty said the company's stock has just now become available for trading. "We're starting to see upticks, but it's been kind of a mess," he said referring to Nasdaq delays.

"Historically, it would be usual to have 30 to 40 companies go public in the last year and we've had only a couple," he said. "If you could show your company as growing, people would invest. But the new paradigm is that you have to show growth, but also that you have money in the bank and can weather the storm. We've got the money to get to profitability and we can live with the cash we raised already."