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                                                                     EXHIBIT 3.1



                                    RESTATED
                          CERTIFICATE OF INCORPORATION
                                       OF
                         RADIANCE MEDICAL SYSTEMS, INC.

                    (PURSUANT TO SECTIONS 242 AND 245 OF THE
                GENERAL CORPORATION LAW OF THE STATE OF DELAWARE)

        Radiance Medical Systems, Inc., a corporation organized and existing
under and by virtue of the provisions of the General Corporation Law of the
State of Delaware (the "General Corporation Law").

        DOES HEREBY CERTIFY:

        FIRST: That this corporation was originally incorporated on June 2,
1993, pursuant to the General Corporation Law, under the name of Cardiovascular
Dynamics, Inc.

        SECOND: That this Restated Certificate of Incorporation restates and
integrates and does not further amend the Certificate of Incorporation of this
corporation as theretofore amended and supplemented, and there is no discrepancy
between those provisions and the provisions of this Restated Certificate of
Incorporation.

        THIRD: That the Restated Certificate of Incorporation of this
corporation, as restated, is as follows:

                                    ARTICLE I

        The name of this corporation is Radiance Medical Systems, Inc.

                                   ARTICLE II

        The address of the registered office of this corporation in the State of
Delaware is 2711 Centreville Road, Suite 400, Wilmington, Delaware, 19808 County
of New Castle. The name of its registered agent at such address is The
Prentice-Hall Corporation System, Inc.

                                   ARTICLE III

        The nature of the business or purposes to be conducted or promoted is to
engage in any lawful act or activity for which corporations may be organized
under the General Corporation Law of Delaware.

                                   ARTICLE IV

        (A) Classes of Stock. This corporation is authorized to issue two
classes of stock, to be designated, respectively, "Common Stock" and "Preferred
Stock." The total number of shares that this corporation is authorized to issue
is thirty-five million (35,000,000). The number of shares of Preferred Stock
authorized to be issued is five million (5,000,000), par value $0.001 per share.
The number of shares of Common Stock authorized to be issued is thirty million
(30,000,000), par value



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$0.001 per share. The shares of Preferred Stock may be issued from time to time
in one or more series. The Board of Directors of this corporation (the "Board of
Directors") is expressly authorized to provide for the issue of all or any of
the remaining shares of the Preferred Stock in one or more series, and to fix
the number of shares and to determine or alter for each such series, such voting
powers, full or limited, or no voting powers, and such designations,
preferences, and relative, participating, optional, or other rights and such
qualifications, limitations or restrictions thereof, as shall be stated and
expressed in the resolution or resolutions adopted by the Board of Directors
providing for the issue of such shares and as may be permitted by the General
Corporation Law of the State of Delaware. Subject to compliance with applicable
protective voting rights which have been granted to the Preferred Stock or
series thereof in Certificates of Designation or the corporation's Certificate
of Incorporation ("Protective Provisions"), but notwithstanding any other rights
of the Preferred Stock or any series thereof, the rights, privileges,
preferences and restrictions of any such additional series may be subordinated
to, pari passu with (including, without limitation, inclusion in provisions with
respect to liquidation and acquisition preferences, redemption and/or approval
of matters by vote or written consent), or senior to any of those of any present
or future class or series of Preferred or Common Stock. Subject to compliance
with applicable Protective Provisions, the Board of Directors is also expressly
authorized to increase or decrease (but not below the number of shares of such
series then outstanding) the number of shares of any series subsequent to the
issue of shares of that series. In case the number of shares of any such series
shall be so decreased, the shares constituting such decrease shall resume the
status they had prior to the adoption of the resolution originally fixing the
number of shares of such series.

        (B)    Common Stock.

        1. Dividend Rights. Subject to the prior rights of holders of all
classes of stock at the time outstanding having prior rights as to dividends,
the holders of the Common Stock shall be entitled to receive, when and as
declared by the Board of Directors, out of any assets of this corporation
legally available therefor, such dividends as may be declared from time to time
by the Board of Directors.

        2. Liquidation Rights. Upon the liquidation, dissolution or winding up
of this corporation, the assets of this corporation shall be distributed among
the holders of Common Stock pro rata based on the number of shares of Common
Stock held by each.

        3. Redemption. The Common Stock is not redeemable.

        4. Voting Rights. The holder of each share of Common Stock shall have
the right to one vote, and shall be entitled to notice of any stockholders'
meeting in accordance with the Bylaws of this corporation, and shall be entitled
to vote upon such matters and in such manner as may be provided by law.

                                    ARTICLE V

        A director of this corporation shall not be personally liable to this
corporation or its stockholders for monetary damages for breach of fiduciary
duty as a director, except for liability (i) for any breach of the director's
duty of loyalty to this corporation or its stockholders, (ii) for acts or
omissions not in good faith or which involve intentional misconduct or a knowing
violation of law,



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(iii) under Section 174 of the Delaware General Corporation Law, or (iv) for any
transaction from which the director derived any improper personal benefit. If
the Delaware General Corporation Law is amended after approval by the
stockholders of this Article to authorize corporation action further eliminating
or limiting the personal liability of directors, then the liability of a
director of this corporation shall be eliminated or limited to the fullest
extent permitted by the Delaware General Corporation Law, as so amended.

        Any repeal or modification of the foregoing paragraph by the
stockholders of this corporation shall not adversely affect any right or
protection of a director of this corporation existing at the time of such repeal
or modification.

                                   ARTICLE VI

        This corporation reserves the right to amend, alter, change or repeal
any provision contained in this Amended and Restated Certificate of
Incorporation, in the manner now or hereafter prescribed by statute, and all
rights conferred upon stockholders herein are granted to this reservation.

                                   ARTICLE VII

        The Board of Directors may from time to time make, amend, supplement or
repeal the Bylaws; provided, however, that the stockholders may change or repeal
any Bylaw adopted by the Board of Directors; and provided, further, that no
amendment or supplement to the Bylaws adopted by the Board of Directors shall
vary or conflict with any amendment or supplement adopted by the stockholders.

                                  ARTICLE VIII

        The number of directors of this corporation shall be fixed from time to
time by a bylaw or amendment thereof duly adopted by the Board of Directors or
by the stockholders. The current Board of Directors shall be divided into three
(3) classes, as nearly equal in number as possible, designated Class I, Class II
and Class III. The number of directors constituting each Class shall be fixed
from time to time by a resolution duly adopted by the Board of Directors. Class
I directors shall hold office for an initial term expiring at the annual meeting
of stockholders in 1999. Class II directors shall hold office for an initial
term expiring at the annual meeting of stockholders in 2000, and Class III
directors shall hold office for a term expiring at the annual meeting of
stockholders in 2001. At each annual meeting of stockholders held thereafter,
directors shall be elected for a three-year term to succeed the directors of the
Class whose terms then expire.

                                   ARTICLE IX

        Elections of directors need not be by written ballot unless the Bylaws
of this corporation shall so provide.

                                    ARTICLE X

        Meetings of stockholders may be held within or without the State of
Delaware, the Bylaws may provide. The books of this corporation may be kept
(subject to any provision contained in the



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statutes) outside the State of Delaware at such place or places as may be
designated from time to time by the Board of Directors or in the Bylaws of this
corporation."

        FOURTH: That the Restated Certificate of Incorporation was duly adopted
by the board of directors without a vote of the stockholders in accordance with
Section 245(b) of the General Corporation Law.

        IN WITNESS WHEREOF, this Restated Certificate of Incorporation has been
signed by the Vice President, Finance and Administration, Chief Financial
Officer as of March 12, 2001.


                                      /s/ STEPHEN R. KROLL
                                     -------------------------------------------
                                     Stephen R. Kroll
                                     Vice President, Finance and Administration,
                                     Chief Financial Officer and Secretary



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