Clinically Significant 12-Month Results from Cardiovascular Systems' Calcium 360° Study Published in Journal of Endovascular Therapy

Study shows sustained durability and statistically significant benefits of orbital atherectomy

Clinically Significant 12-Month Results from Cardiovascular Systems' Calcium 360° Study Published in Journal of Endovascular Therapy

Investor Relations, 651-259-2800orSarah Wozniak, 651-259-1636orMatt Sullivan, 612-455-1709orDave Folkens, 612-455-1741

Cardiovascular Systems, Inc. (CSI) (NASDAQ: CSII), a medical device company developing and commercializing innovative interventional treatment systems for vascular disease, today announced publication of 12-month results from its CALCIUM 360° study in the Journal of Endovascular Therapy, August 2012.

CALCIUM 360° is a prospective, randomized, multi-center study of 50 patients (64 lesions), comparing one-year safety and efficacy of CSI’s Diamondback 360° atherectomy device followed by percutaneous transluminal angioplasty (PTA), versus PTA alone, to treat calcified infrapopliteal lesions in patients with critical limb ischemia.

Based on the study results, the Diamondback 360° system provides significantly lower major serious adverse events (major amputation, all-cause mortality, and TLR/TVR) than PTA alone. The Diamondback arm demonstrated that lower balloon pressure is needed to achieve optimal dilatation (p <0.001), resulting in fewer procedural events for peripheral arterial disease (PAD) patients. At 12 months, the Diamondback 360° group was 93.3 percent free of major adverse events (major amputation, all-cause mortality and TLR/TVR) versus just 57.9 percent of the balloon angioplasty alone (p = 0.006) group.

Additional results show:

(*Per lesion ** Per patient)

Click to see the full abstract.

According to David L. Martin, CSI president and CEO, “The CALCIUM 360° study demonstrates that our technology provides patients and physicians with a better therapy. It provides optimal balloon dilatation and significantly lowers complications. Our expanding clinical data set continues to demonstrate that the Diamondback 360° system is setting a new standard for treating calcified lesions.”

The CALCIUM 360° study builds on CSI’s history of clinical evidence and positive outcomes already seen in CSI’s OASIS and COMPLIANCE 360° trials. Studies demonstrate sustained durability and low revascularization rates for CSI’s orbital atherectomy systems with low-pressure PTA.

PAD is a life-threatening condition where a fatty material called plaque builds up on the inside walls of the blood vessels that carry blood from the heart to legs and arms. The plaque buildup causes the arteries to harden and narrow (atherosclerosis), reducing blood flow to the legs. The risk of PAD increases if a person has one or several of the following: high blood pressure, abnormal cholesterol levels, diabetes, or personal history of heart disease, heart attack or stroke. PAD affects an estimated 8-12 million people in the United States. The disease prevalence increases with age and 12-20 percent of Americans age 65 and older suffer from PAD symptoms. As the U.S. population ages, the prevalence range could reach 16 million in those age 65 and older and 19 million overall by 2050.

Cardiovascular Systems, Inc., based in St. Paul, Minn., is a medical device company focused on developing and commercializing innovative solutions for treating vascular and coronary disease. The company’s Diamondback Orbital Atherectomy System treats calcified and fibrotic plaque in arterial vessels throughout the leg in a few minutes of treatment time, and addresses many of the limitations associated with existing surgical, catheter and pharmacological treatment alternatives. The U.S. FDA granted 510(k) clearance for the use of the Diamondback Orbital Atherectomy System in August 2007. To date, more than 70,000 PAD procedures have been performed using CSI’s technology in leading institutions across the United States. CSI has also commenced its ORBIT II Investigational Device Exemption clinical trial to evaluate the safety and effectiveness of its orbital technology in treating coronary arteries.

For more information, visit the company’s website at .

Certain statements in this news release are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and are provided under the protection of the safe harbor for forward-looking statements provided by that Act. For example, statements in this press release regarding (i) CSI’s belief that orbital atherectomy can play a role in promoting certain beneficial patient outcomes and (ii) the future prevalence range for PAD, are forward-looking statements. These statements involve risks and uncertainties which could cause results to differ materially from those projected, including but not limited to the potential for unanticipated delays in enrolling medical centers and patients for clinical trials; dependence on market growth; the reluctance of physicians to accept new products; the effectiveness of the Diamondback™ Orbital Atherectomy System; actual clinical trial results; the impact of competitive products and pricing; the difficulty to successfully manage operating costs; fluctuations in quarterly results; FDA clearances and approvals; approval of products for reimbursement and the level of reimbursement; general economic conditions and other factors detailed from time to time in CSI’s SEC reports, including its most recent annual report on Form 10-K and subsequent quarterly reports on Form 10-Q. CSI encourages you to consider all of these risks, uncertainties and other factors carefully in evaluating the forward-looking statements contained in this release. As a result of these matters, changes in facts, assumptions not being realized or other circumstances, CSI's actual results may differ materially from the expected results discussed in the forward-looking statements contained in this release. The forward-looking statements made in this release are made only as of the date of this release, and CSI undertakes no obligation to update them to reflect subsequent events or circumstances.

The Diamondback Orbital Atherectomy System is indicated for use as therapy in patients with occlusive atherosclerotic disease in peripheral arteries and stenotic material from artificial arteriovenous dialysis fistulae. The system is contraindicated for use in coronary arteries, bypass grafts, stents or where thrombus or dissections are present. Although the incidence of adverse events is rare, potential events that can occur with atherectomy include: pain, hypotension, CVA/TIA, death, dissection, perforation, distal embolization, thrombus formation, hematuria, abrupt or acute vessel closure, or arterial spasm.