NOTE CONTRIBUTION AND EXCHANGE AGREEMENT

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Exhibit 2.3

NOTE CONTRIBUTION AND EXCHANGE AGREEMENT

        This Note Contribution and Exchange Agreement, dated as of April 4, 2005 (the " Agreement "), is entered into by and among the noteholders listed on Schedule I hereto (each, a " Noteholder " and collectively, the " Noteholders "), ev3 Endovascular Inc. (formerly known as ev3 Inc.), a Delaware corporation (" ev3 Endovascular "), and ev3 Inc., a Delaware corporation (the " Company "). Capitalized terms used herein and not otherwise defined shall have the meanings ascribed to such terms in Section 8.1 of this Agreement.

R E C I T A L S

         WHEREAS , the Noteholders are the owners of the demand notes of ev3 Endovascular, which following the Merger (as defined below) will be a wholly owned subsidiary of the Company, set forth opposite such Noteholders' names on Schedule II hereto (collectively, the " Notes ");

         WHEREAS , the Company intends to file a Registration Statement on Form S-1 (the " Registration Statement ") with the SEC pursuant to which it will pursue the Initial Public Offering of its common stock, par value $0.01 per share (" Company Common Stock ");

         WHEREAS , simultaneously with the execution of this Agreement, the Company and ev3 LLC, a Delaware limited liability company (" ev3 LLC "), will enter into an agreement and plan of merger (the " Merger Agreement ") pursuant to which ev3 LLC will agree, on the terms and subject to the conditions set forth in the Merger Agreement, to merge (the " Merger ") with and into the Company with the Company surviving the Merger, as more fully described in the Merger Agreement;

         WHEREAS , simultaneously with the execution of this Agreement, the Company, ev3 LLC and certain institutional stockholders named therein will enter into a contribution and exchange agreement (the " Contribution Agreement ") pursuant to which the stockholders will agree, on the terms and subject to the conditions set forth in the Contribution Agreement, to contribute to ev3 LLC common stock of Micro Therapeutics, Inc., a Delaware corporation, in exchange for common membership units of ev3 LLC, as more fully described in the Contribution Agreement; and

         WHEREAS , on the terms and subject to the conditions set forth in this Agreement, including, without limitation, Article VI herein, effective at the Closing (as defined in Section 2.1) the Noteholders desire to contribute to the Company, and the Company desires to accept from the Noteholders, the Notes owned by them as a contribution to capital (the " Contribution "), in exchange (the " Exchange ") for the issuance to the Noteholders of the number of shares of Company Common Stock determined in the manner set forth in Section 1.3 below (collectively, the " Company Shares ").

         NOW, THEREFORE , in consideration of the premises and for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto, intending to be legally bound, agree as follows:

ARTICLE I.
CONTRIBUTION AND EXCHANGE

         Section 1.1.     Contribution of Notes.     On the basis of the representations, warranties and agreements contained herein, and subject to the terms and conditions hereof, including, without limitation, the satisfaction (or waiver, to the extent permitted by this Agreement and applicable law) of the conditions set forth in Article VI of this Agreement, effective at the Closing each of the Noteholders agrees to contribute, transfer, assign and convey to the Company all right, title and interest in and to all of the Notes owned directly by such Noteholder, together with any and all rights, privileges, benefits, obligations and liabilities appertaining thereto, including in respect of any right to receive interest thereon through the Deemed Interest Accrual Date (as defined below) reserving unto such Noteholder no rights or interests therein whatsoever, to have and to hold the

same unto the Company and its heirs, legal representatives, successors and assigns, from and after the Closing to its own proper use forever; provided , that upon prior written notice (a " Repayment Notice ") to the Noteholders, the Company may repay, on or prior to the IPO Closing Date, on a pro rata basis, all or any portion of the Notes, together with accrued and unpaid interest thereon to and including the Deemed Interest Accrual Date; provided , further , that notwithstanding anything to the contrary contained in any Note, the Company shall so notify the Noteholders pursuant to a Repayment Notice prior to the first business day next preceding the Closing Date. The Company agrees that prior to repayment of any Notes subject to this Agreement, the Company shall use at least $75 million of the net proceeds of the Initial Public Offering to repay any demand notes, together with accrued and unpaid interest thereon, held by the Noteholders that may be issued by ev3 Endovascular to the Noteholders after the date hereof.

         Section 1.2.     Acceptance of Contribution.     On the basis of the representations, warranties and agreements contained herein, and subject to the terms and conditions hereof, effective at the Closing the Company hereby agrees to accept the Contribution of the Notes pursuant to Section 1.1 and to thereafter cancel the Notes such that the Notes no longer remain outstanding.

         Section 1.3.     Exchange.     In consideration of the Contribution by the Noteholders and on the basis of the representations, warranties and agreements contained herein, and subject to the terms and conditions hereof, on the Closing Date and in exchange for the Notes contributed to the Company pursuant to Section 1.1, the Company shall issue and deliver to each Noteholder the number of shares of Company Common Stock determined by dividing (i) the aggregate principal amount of Notes outstanding that are to be contributed to the Company by such Noteholder pursuant to Section 1.1, together with accrued and unpaid interest thereon to and including the Deemed Interest Accrual Date by (ii) the per share initial public offering price (before giving effect to the underwriting discount), as set forth on the cover of the final prospectus for the Initial Public Offering. As used herein, the " Deemed Interest Accrual Date " shall mean (i) in the event the IPO Closing Date occurs on a date that is 120 days or less from the Initial Filing Date, the date that is 90 days from the date the Registration Statement is first filed by the Company with the SEC (the " Initial Filing Date ") and (ii) in the event the IPO Closing Date occurs on a date that is more than 120 days from the Initial Filing Date, the IPO Closing Date. For the avoidance of doubt, the Deemed Interest Accrual Date is illustrated by reference to the period from the Initial Filing Date through the IPO Closing Date as set forth in the table below. For purposes of calculating the Deemed Interest Accrual Date, the Initial Filing Date shall be counted. References to days in the table below shall be to calendar days.

        By way of example, if the IPO Filing Date is March 15 and the IPO Closing Date is June 30, the Deemed Interest Accrual Date shall be June 12. If the IPO Filing Date is March 15 and the IPO Closing Date is July 31, the Deemed Interest Accrual Date shall be July 31.

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         Section 1.4.     Interest on Notes.     Notwithstanding anything to the contrary contained herein or in the Notes, in the event the IPO Closing Date occurs during the period beginning on and including the date that is 91 days from the Initial Filing Date through and including the date that is 120 days from the Initial Filing Date (the " Interest Relief Period "), ev3 Endovascular shall be relieved of its obligations to pay accrued and unpaid interest in respect of any Notes for such Interest Relief Period. For purposes of calculating the Interest Relief Period, the Initial Filing Date shall be counted. By way of example, if the IPO Filing Date is March 15 and the IPO Closing Date is June 30, the Interest Relief Period shall be June 13 through and including June 30. If the IPO Filing Date is March 15 and the IPO Closing Date is July 31, there shall be no Interest Relief Period.

         Section 1.5.     No Fractional Shares.     Notwithstanding anything to the contrary contained herein, no certificates or scrip representing fractional shares of Company Common Stock shall be issued to any Noteholder in connection with the Exchange. Instead, any fractional shares of Company Common Stock that a Noteholder would otherwise be entitled to receive as a result of the Exchange shall be rounded up to the nearest whole number of shares of Company Common Stock.

         Section 1.6.     Power of Attorney.     From and after the Closing Date, each Noteholder constitutes and appoints the Company, its successors and assigns, as the Noteholder's true and lawful attorney-in-fact, with full power of substitution, in the name of the Company or in the name of the Noteholder, to execute, deliver, file and/or record such documents, agreements and instruments as shall be necessary or appropriate to effect the Contributions pursuant to this Article I. The foregoing powers are coupled with an interest and shall be irrevocable.

         Section 1.7.     Characterization.     The Contribution, the transactions described in the Merger Agreement and the Contribution Agreement and the public's purchase of stock in the Initial Public Offering are part of an integrated plan and are intended together to qualify as a tax-free transaction under Section 351 of the Internal Revenue Code of 1986, as amended.

ARTICLE II.
CLOSING

         Section 2.1.     Closing.     The closing of the transactions contemplated by this Agreement (the " Closing ") shall take place at 9:30 a.m., New York City time, on the closing date of the Initial Public Offering (the " IPO Closing Date ") or on such other date as may be mutually agreed to by the Company and the Noteholders (a) after the per share price of the Company Common Stock to be sold in the Initial Public Offering is finally determined, (b) as close to (but in any event prior to) the IPO Closing Date as reasonably practicable, (c) after the Effective Time (as defined in the Merger Agreement) of the Merger and (d) after the effectiveness of any reverse split declared on the Company Common Stock that is to take effect prior to the consummation of the Initial Public Offering (the " Closing Date "); provided , that on or before the Closing Date, all of the conditions set forth in Article VI shall have been fulfilled or waived in accordance with this Agreement (except for those conditions that will be fulfilled or waived as a result of the closing of the Initial Public Offering), at the offices of King & Spalding LLP, 1185 Avenue of the Americas, New York, New York, or such other location as the Company and the Noteholders shall mutually select.

         Section 2.2.     Closing Deliveries.     At the Closing,

        (a)   Each Noteholder shall deliver to the Company the Notes being contributed by such Noteholder, duly endorsed and in appropriate form and sufficient for transfer of the Notes to the Company.

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        (b)   The Company shall deliver to each Noteholder a duly executed stock certificate representing the shares of Company Common Stock to be issued to such Noteholder pursuant to this Agreement.

ARTICLE III.
REPRESENTATIONS AND WARRANTIES OF THE COMPANY

        The Company represents and warrants to each of the Noteholders as follows:

         Section 3.1.     Organization.     The Company is a corporation duly organized, validly existing and in good standing under the laws of the State of Delaware.

         Section 3.2.     Authority.     The Board of Directors of the Company has authorized the execution, delivery and performance of this Agreement and the transactions contemplated hereby, including, without limitation, the issuance and delivery of the Company Shares to the Noteholders in accordance with the terms of this Agreement. No other corporate action is necessary to authorize such execution, delivery and performance, and upon such execution and delivery, this Agreement shall constitute a valid and binding obligation of the Company, enforceable against the Company in accordance with its terms, except as enforceability may be limited by bankruptcy, insolvency or other similar laws affecting the enforcement of creditor's rights generally or by general principles of equity.

         Section 3.3.     Issuance of Shares.     The Company Shares to be issued by the Company pursuant to this Agreement, when issued in accordance with the provisions hereof, will be validly issued by the Company, fully paid and nonassessable, and, no stockholder of the Company has, or will have, any preemptive rights to subscribe for any Company Common Stock.

         Section 3.4.     Consents; Conflicts.     Except with respect to filings made in connection with exemptions from registration under state or federal securities laws, the creation, authorization, issuance, offer and sale of the Company Shares do not require any consent, approval or authorization of, or filing, registration or qualification with, any Person or governmental authority on the part of