Cardiovascular Systems, Inc.Redefining InterventionalVascular Solutions

William Blair Healthcare ConferenceJune 11, 2015

SAFE HARBOR

FORWARD-LOOKING STATEMENTS

Certain statements made in this presentation 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. In some cases, you can identify forward-looking statements by terms such as may, will, should, could, would, expect, plans, anticipates, believes, estimates, projects, predicts, potential and similar expressions intended to identify forward-looking statements. Examples of these statements include, but are not limited to, statements regarding Cardiovascular System, Inc.s (CSI or the Company) future financial performance, product sales distribution, industry and market expectations, the benefits and uses of the Companys products, use of proceeds, results of operations, prospects, plans and objectives of management, and other statements that are other than statements of historical fact.

These statements involve risks and uncertainties which could cause results to differ materially from those projected, including those described under the heading Risk Factors contained in the prospectus filed with the Securities and Exchange Commission (the SEC) for our recent public offering, and as detailed from time to time in CSIs SEC reports, including its Reports on Form 10-K and Form 10-Q. 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 presented. The forward-looking statements are made only as of the date of this presentation, and CSI undertakes no obligation to update them to reflect subsequent events or circumstances.

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Large, underserved markets

Highly differentiated products

Strong clinical data

Attractive financial profile

CSI TODAY

37%CSIs revenue growth

YTD fiscal 2015

$14BCombined PAD

and CAD U.S. market opportunity

200,000Orbital Atherectomy

Systems that have been sold

5,000+Patients enrolled

in CSI clinical studies

2High-margin,

high-growth orbital atherectomy

franchises

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Nearly

Simple Speed Settings

Instant Response On/Off Switch

Saline Pump Mounts on I.V. pole Bathes shaft and crown for smooth operation

Crowns Offset weight = orbital action Small profile for small vessels and

alternative access sites

CSI ORBITAL ATHERECTOMY SYSTEMS (OAS)Power and simplicity for streamlined setup and treatment

Sleek Electric-Powered Handle Simple set-up Optimum torque transfer to the shaft and crown Short treatment times

Crowns shown are not to scale and for illustrative purposes only.

Coronary Approved October 2013

Peripheral

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Heart to heels capabilityWe treat 11 vessels.Large and small.

1 1Above the Knee

3HeartCSI: WHY WERE UNIQUE

Effective in calcium

Excellent safety

Long-term durability

Economical

Below the Knee 33

Alternative access sites

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CSI: WHY WERE UNIQUE

Alternative access sites

Femoral

PedalTibial

Radial

Brachial

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93% < red blood cell size

99% < lumen size of capillaries

UNIQUE MECHANISM OF ACTIONBi-directional and differential sanding

Calculation of mean particulate size is based particles larger than 1 micron from a representative study using carbon blocks and cadaver model systems.

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OAS DELIVERS OPTIMAL VESSEL PREP AS THE PRIMARY TREATMENT FOR CALCIFIED LESIONS

OAS

Scoring Balloon

Rotablator

High Pressure Balloon

Smooth Concentric Lumen Incomplete Vessel Prep

Poly-traumatic vessel Injury Flow Limiting Dissection

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LARGE AND GROWING MARKETS

CAD 1.4 million U.S. interventional procedures 38% with significant calcium $1.5+ billion market opportunity

PAD Affects 18 million people in U.S. 4.0 million with critical limb ischemia Only 300,000 CLI patients receive interventions

annually (160,000 get debilitating amputations) $12+ billion market opportunity

Innovation for unmet needs driving market expansion

$14BCombined

PAD and CAD U.S.market opportunity

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Annual U.S. CAD procedures % with significant calcium

CSI market potential(>$1.5 Billion)

Sources: Millennium Research Group Inc 2014., National Hospital Discharge Survey 2009, CSI estimates.

LARGE CORONARY MARKET POTENTIAL

38%28%

400,0001.4

MILLION

16 MILLION U.S. CAD PATIENTS DIAGNOSED

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PAD IS A LARGE AND UNDERSERVED MARKETCritical limb ischemia (CLI) is vastly undertreated

18 million people in U.S. with PAD4 million people with CLI

2.5 milliondiagnosed

600K proceduralinterventions

Sources: Sage Group, Millennium Research Group US Markets for Peripheral Intervention Devices 2014, iData US Market for Peripheral Vascular Devices and Accessories 2014, and Go, et al Heart Disease and Stroke Statistics -- 2014 Update, Circulation.

600K Interventions(300K for CLI)

$12B+ CLI market opportunity in U.S. and growing

Amputationsand Bypass

(CLI)

High Pressure Balloons and

Stents

PlaqueRemoval

CLI(6 Million by

2030)

Growth StrategyMarket expansion (underserved CLI patients)Reduce amputation/bypassReduce high pressure ballooning/stenting

65% calcified

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Only device to broadly treat the disease

Source: CSI data on file, Millennium Research Group

Industry Procedure Mix

BTK - 80% calcified20% require ankle/foot access

CSI mix/disease prevalence

ATK - 40% calcified

OAS TECHNOLOGY EXPANDS PAD MARKET

ABOVE THE KNEE

BELOWTHE KNEE

BELOWTHE KNEE

ABOVETHE KNEE

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HOSPITAL

INPATIENT

OUTPATIENT

PAD $10,150 $19,148CAD $11,032 $18,985

PAD (ATK) $ 9,624PAD (BTK)/CAD $14,841

NON-HOSPITAL FACILITY

ATTRACTIVE REIMBURSEMENT RATES (2015)

PAD $11,083 $15,175

Small vessels receive higher reimbursement

1. DRG Codes 246, 247, 248, 249, 250, 251, 252, 253, 2542. CPT Codes 37225, 37227, 37229, 37231, 929333. APC Codes 0229, 0319, 083 4. HCPCS Code C9602

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CSI has studied more than 5,000real-world patients, treated 7,000lesions and worked with 600+ physicians

OASIS, CONFIRM series, Calcium 360 and Compliance 360, demonstrated: Low rates of adverse events

and bail-out stenting High rates of success Durable results

LIBERTY 360 (enrolling) Evaluating acute and long-term

clinical and economic outcomes of CSIs OAS vs. any other treatment

Up to 1,200 patients (noexclusions) at up to 100 U.S. sites

Study will include claudication, CLI, patients scheduled for amputation

BACKED BY CLINICAL SCIENCE

Key PAD Trials

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BACKED BY CLINICAL SCIENCE

Key CAD Trials

ORBIT II Beat primary endpoints by significant

margins in severely calcified lesions

Two-year data showed 94% freedom from target lesion revascularization

Two-year extrapolated economic analysis cost savings of up to $4,946per patient from shorter hospital stays and lower readmission rates

COAST (enrolling) International investigational

study to assess safety, efficacy and economic outcomes of new micro crown OAS

Up to 100 patients at up to20 sites in the U.S. and Japan

Japan enrollment completed

Designed to secure commercialapproval for second-gen OASdevice in Japan

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SALES OPTIMIZATION STRATEGY

December 2013 Today December 2015

Hybrid100

Hybrid 200+CAD 5

PAD 100

Expand sales footprint One rep selling two, high-margin, high-growth franchises Cover largest procedure accounts Deeper penetration into existing accounts Hybrid productivity well above PAD- or CAD-only reps

CAD 10

PAD 130

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$82.5

$103.9

$131.2

$95.0

$113.9

$136.6$133.1

$0

$40

$80

$120

$160

FY 12 FY 13 FY 14 FY 14 (9 mo.) FY 15 (9 mo.)

PAD CAD

31

%

37

%

26

% $97.0

ACCELERATING REVENUE GROWTHQuality Revenue

$ M

illio

ns

Sales life-to-date

Nearly 200,000 Devices, 1,700 Accounts

96% Reorder Revenue

U.S. only, CAD launch in Q2 2014

$19.2 CAD

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Quarterly Revenue growth over prior year11 Quarters 25% or greater growth

0%

10%

20%

30%

40%

Q113

Q213

Q313

Q413

Q114

Q214

Q314

Q414

Q115

Q215

Q315

25% 28% 25% 26%28% 28%

31%

37%39% 38%

35%

% Y

ear

ove

r Ye

ar G

row

th

Growth accelerated with CAD

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STRONG, IMPROVING GROSS MARGINS

70%

75%

80%

FY 13 FY 14 FY 15 (9 mo.)

76.5%

77.3%

78.5%

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INVESTING FOR ACCELERATED REVENUE GROWTHFuture profitability potential

Adjusted EBITDA = EBITDA, excluding stock-based compensation expense. For a reconciliation of this non-GAAP financial measure, please refer to the reconciliation tables in our most recent Form 10-K and Form 10-Q.

-20%

-15%

-10%

-5%

0%

5%

10%

15%

20%

25%

FY 13 FY 14 FY 15 (9 mo.) Future Target

(9%)

2%

(16%)

Adjusted EBITDA Margin Adjusted EBITDA Margin (excluding net coronary investment)

6%

(13%)

5%

% o

f R

eve

nu

e20%-25%

Upfront CAD investment = long-term growth/operating leverage

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SOLID BALANCE SHEETAmple cash to implement current strategy

$0

$20

$40

$60

$80

$100

Jun. 2013 Mar. 2015

$12

$93.5

$68

$0.0

Debt Principal Cash

$ M

illio

ns

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Large, underserved markets

Highly differentiated products

Strong clinical data

Attractive financial profile

WHY CSI?

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DIAMONDBACK 360 Coronary Orbital Atherectomy System

Indications: The DIAMONDBACK 360 Coronary Orbital Atherectomy System(OAS) is a percutaneous orbital atherectomy system indicated to facilitate stent delivery in patients with coronary artery disease (CAD) who are acceptable candidates for PTCA or stenting due to de novo, severely calcified coronary artery lesions.

Contraindications: The OAS is contraindicated when the VIPERWIRE guidewire cannot pass across the coronary lesion or the target lesion is within abypass graft or stent. The OAS is contraindicated when the patient is not anappropriate candidate for bypass surgery, angioplasty, or atherectomytherapy, or has angiographic evidence of thrombus, or has only one open vessel, or has angiographic evidence of significant dissection at the treatment site and for women who are pregnant or children.

Warnings/Precautions:; Performing treatment in excessively tortuous vesselsor bifurcations may result in vessel damage; The OAS was only evaluated inseverely calcified lesions, A temporary pacing lead may be necessary whentreating lesions in the right coronary and circumflex arteries; On-site surgicalback-up should be included as a clinical consideration; Use in patients with anejection fraction (EF) of less than 25% has not been evaluated.See the instructions for use before performing DIAMONDBACK 360 coronaryorbital atherectomy procedures for detailed information regarding the procedure, indications, contraindications, warnings, precautions, and potential adverse events. For further information call CSI at 1-877-274-0901 and/or consult CSIs website at www.csi360.com .

Caution: Federal law (USA) restricts this device to sale by or on the order of aphysician.

The Diamondback 360 and Stealth 360 Peripheral Atherectomy SystemsThe Diamondback 360 and Stealth 360 PAD Systems are percutaneous orbital atherectomy systems indicated for use as therapy in patients with occlusive atherosclerotic disease in peripheral arteries and stenoticmaterial from artificial arteriovenous dialysis fistulae. The Systems arecontraindicated for use in coronary arteries, bypass grafts, stents, or wherethrombus 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. For further information call CSI at 1-877-274-0901 and/or consult CSIs website at www.csi360.com .

Caution: Federal law (USA) restricts this device to sale by or on the order of a physician.

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Investor Contact:Jack NielsenSenior Director Corporate Communications & Investor Relations651-202-4919j.nielsen@csi360.com

2015 Cardiovascular Systems, Inc.All Rights ReservedDiamondback 360 and CSI are registered trademarks of Cardiovascular Systems, Inc.www.csi360.com

NASDAQ: CSII

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