TRIVASCULAR TECHNOLOGIES, INC. 2014 EMPLOYEE STOCK PURCHASE PLAN APPROVED BY THE BOARD OF DIRECTORS , 2014 APPROVED BY STOCKHOLDERS , 2014 EFFECTIVE DATE/IPO DATE , 2014

Exhibit 10.4

TRIVASCULAR TECHNOLOGIES, INC.

2014 EMPLOYEE STOCK PURCHASE PLAN

APPROVED BY THE BOARD OF DIRECTORS                      , 2014

APPROVED BY STOCKHOLDERS                      , 2014

EFFECTIVE DATE/IPO DATE                      , 2014

(a) The purpose of this 2014 Employee Stock Purchase Plan (the “Plan”) is to provide a means by which employees of TriVascular Technologies, Inc. (the “Company”) and its Affiliates, as defined in subparagraph 1(b), that are designated as provided in subparagraph 2(b), may be given an opportunity to purchase common stock of the Company (the “Common Stock”).

(b) The word “Affiliate” as used in the Plan means any parent corporation or subsidiary corporation of the Company, as those terms are defined in Sections 424(e) and (f), respectively, of the Internal Revenue Code of 1986, as amended (the “Code”).

(c) The Company, by means of the Plan, seeks to retain the services of its employees, to secure and retain the services of new employees, and to provide incentives for such persons to exert maximum efforts for the success of the Company.

(d) The Company intends that the rights to purchase stock of the Company (each, a “Purchase Right” and, collectively, “Purchase Rights”) granted under the Plan be considered options issued under an “employee stock purchase plan” as that term is defined in Section 423(b) of the Code.

(a) The Plan shall be administered by the Board of Directors (the “Board”) of the Company unless and until the Board delegates administration to a Committee, as provided in subparagraph 2(c). Whether or not the Board has delegated administration, the Board shall have the final power to determine all questions of policy and expediency that may arise in the administration of the Plan.

(b) The Board shall have the power, subject to, and within the limitations of, the express provisions of the Plan:

(i) To determine when and how Purchase Rights shall be granted and the provisions of each offering of such Purchase Rights (which need not be identical).

(ii) To designate from time to time which Affiliates of the Company shall be eligible to participate in the Plan.

(iii) To construe and interpret the Plan and Purchase Rights, and to establish, amend and revoke rules and regulations for its administration. The Board, in the exercise of this power, may correct any defect, omission or inconsistency in the Plan, in a manner and to the extent it shall deem necessary or expedient to make the Plan fully effective.

(iv) To amend the Plan as provided in paragraph 13.

(v) To terminate or suspend the Plan as provided in paragraph 15.

(vi) Generally, to exercise such powers and to perform such acts as the Board deems necessary or expedient to promote the best interests of the Company and its Affiliates and to carry out the intent that the Plan be treated as an “employee stock purchase plan” within the meaning of Section 423 of the Code.

(c) The Board may delegate administration of the Plan to a Committee composed of not fewer than two (2) members of the Board (the “Committee”). If administration is delegated to a Committee, the Committee shall have, in connection with the administration of the Plan, the powers theretofore possessed by the Board, subject, however, to such resolutions, not inconsistent with the provisions of the Plan, as may be adopted from time to time by the Board. The Board may abolish the Committee at any time and revest in the Board the administration of the Plan.

(a) Subject to the provisions of paragraph 12 relating to adjustments upon changes in stock and subject to the increases in the number of reserved shares described below, the stock that may be sold pursuant to Purchase Rights granted under the Plan shall not exceed in the aggregate 500,000 shares of Common Stock (the “Reserved Shares”). If any Purchase Right granted under the Plan shall for any reason terminate without having been exercised, the Common Stock not purchased under such Purchase Right shall again become available for the Plan.

(b) The number of shares of Common Stock available for grant and issuance under the Plan shall be increased on January 1 of each of the first ten (10) calendar years during the term of the Plan by the least of: (i) one percent (1.0%) of the number of shares of Common Stock issued and outstanding on each December 31 immediately prior to the date of increase; or (ii) such number of shares of Common Stock determined by the Board prior to the start of the year for which the increase applies.

(c) The stock subject to the Plan may be unissued shares or reacquired shares, bought on the market or otherwise.

The Board or the Committee may from time to time grant or provide for the grant of Purchase Rights under the Plan to eligible employees (an “Offering”) on a date or dates (the “Offering Date(s)”) selected by the Board or the Committee. Each Offering shall be in such form and shall contain such terms and conditions as the Board or the Committee shall deem appropriate, which shall comply with the requirements of Section 423(b)(5) of the Code that all employees granted Purchase Rights under the Plan shall have the same rights and privileges. The terms and conditions of an Offering shall be incorporated by reference into the Plan and treated as part of the Plan. The provisions of separate Offerings need not be identical, but each Offering shall include (through incorporation of the provisions of this Plan by reference in the document comprising the Offering or otherwise) the period during which the Offering shall be effective, which period shall not exceed twenty-seven (27) months beginning with the Offering Date, and the substance of the provisions contained in paragraphs 5 through 8, inclusive.

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(a) Purchase Rights may be granted only to employees of the Company or, as the Board or the Committee may designate as provided in subparagraph 2(b), to employees of any Affiliate of the Company. Except as provided in subparagraph 5(b), an employee of the Company or any Affiliate shall not be eligible to be granted Purchase Rights under the Plan unless, on the Offering Date, such employee has been in the employ of the Company or any Affiliate for such continuous period preceding such grant as the Board or the Committee may require, but in no event shall the required period of continuous employment be greater than two (2) years. In addition, unless otherwise determined by the Board or the Committee and set forth in the terms of the applicable Offering, no employee of the Company or any Affiliate shall be eligible to be granted Purchase Rights under the Plan, unless, on the Offering Date, such employee’s customary employment with the Company or such Affiliate is for at least twenty (20) hours per week and at least five (5) months per calendar year.

(b) Purchase Rights may not be granted to individuals who are not employees of the Company or any of its Affiliates, including, without limitation, to consultants or members of the Board of the Company or of an Affiliate who are not otherwise employees. For purposes of this Plan, neither service as a consultant or a director or in any other capacity other than as an employee nor payment of a fee for such services shall be sufficient by themselves to make an individual an employee.

(c) The Board or the Committee may provide that each person who, during the course of an Offering, first becomes an eligible employee of the Company or designated Affiliate will, on a date or dates specified in the Offering which coincides with the day on which such person becomes an eligible employee or occurs thereafter, receive a Purchase Right under that Offering, which Purchase Right shall thereafter be deemed to be a part of that Offering. Such Purchase Right shall have the same characteristics as any Purchase Rights originally granted under that Offering, as described herein, except that:

(i) the date on which such Purchase Right is granted shall be the “Offering Date” of such Purchase Right for all purposes, including determination of the exercise price of such Purchase Right;

(ii) the period of the Offering with respect to such Purchase Right shall begin on its Offering Date and end coincident with the end of such Offering; and

(iii) the Board or the Committee may provide that if such person first becomes an eligible employee within a specified period of time before the end of the Offering, he or she will not receive any Purchase Right under that Offering.

(d) No employee shall be eligible for the grant of any Purchase Rights under the Plan if, immediately after any such Purchase Rights are granted, such employee owns stock possessing five percent (5%) or more of the total combined voting power or value of all classes of stock of the Company or of any Affiliate. For purposes of this subparagraph 5(d), the rules of Section 424(d) of the Code shall apply in determining the stock ownership of any employee, and stock which such employee may purchase under all outstanding Purchase Rights and options shall be treated as stock owned by such employee.

(e) An eligible employee may be granted Purchase Rights under the Plan only if such Purchase Rights, together with any other rights granted under “employee stock purchase plans” of the Company and any Affiliates, as specified by Section 423(b)(8) of the Code, do not permit such employee’s rights to purchase stock of the Company or any Affiliate to accrue at a rate which exceeds

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twenty-five thousand dollars ($25,000) of Fair Market Value (as defined below) of such stock (determined at the time such rights are granted, and which with respect to the Plan, will be determined as of their respective Offering Dates) for each calendar year in which such rights are outstanding at any time.

(f) Officers of the Company and any designated Affiliate, if they are otherwise eligible employees, shall be eligible to participate in Offerings under the Plan; provided, however, that the Board may provide in an Offering that certain employees who are highly compensated employees within the meaning of Section 423(b)(4)(D) of the Code shall not be eligible to participate.

(a) On each Offering Date, each eligible employee, pursuant to an Offering made under the Plan, shall be granted a Purchase Right to purchase up to the number of shares of Common Stock of the Company purchasable with a percentage (in whole percentages only) designated by the Board or the Committee not exceeding fifteen (15%) of such employee’s Earnings (as defined in subparagraph 7(a)) during the period which begins on the Offering Date (or such later date as the Board or the Committee determines for a particular Offering) and ends on the date stated in the Offering, which date shall be no later than the end of the Offering. The Board or the Committee shall establish one or more dates during an Offering (the “Purchase Date(s)”) on which Purchase Rights granted under the Plan for that Offering shall be exercised and purchases of Common Stock carried out in accordance with such Offering.

(b) In connection with each Offering made under the Plan, the Board or the Committee shall specify a maximum number of shares that may be purchased by any employee. In addition, in connection with each Offering, the Board or the Committee may specify a maximum aggregate number of shares that may be purchased by all eligible employees pursuant to such Offering. In addition, in connection with each Offering that contains more than one Purchase Date, the Board or the Committee may specify a maximum aggregate number of shares which may be purchased by all eligible employees on any given Purchase Date under the Offering. If the aggregate purchase of shares upon exercise of Purchase Rights granted under the Offering would exceed any such maximum aggregate number, the Board or the Committee shall make a pro rata allocation of the shares available in as nearly a uniform manner as shall be practicable and as it shall deem to be equitable.

(c) The purchase price of stock acquired pursuant to Purchase Rights granted under the Plan shall be not less than the lesser of:

(i) an amount equal to eighty-five percent (85%) of the Fair Market Value of the stock on the Offering Date; or

(ii) an amount equal to eighty-five percent (85%) of the Fair Market Value of the stock on the applicable Purchase Date.

(d) For the purposes of the Plan, the “Fair Market Value” means, as of any date, the value of a share of the Company’s Common Stock determined as follows:

(i) If such Common Stock is publicly traded and is then listed on a national securities exchange, its closing sale price on the date of determination as quoted on the principal national securities exchange on which the Common Stock is listed or admitted to trading as reported in The Wall Street Journal or such other source as the Board deems reliable. Unless otherwise provided by the Board, if there is no closing sales price for the Common Stock on the date of determination, then the Fair Market Value will be the closing sales price on the last preceding date for which such quotation exists.

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(ii) If such Common Stock is publicly traded but is neither listed nor admitted to trading on a national securities exchange, the average of the closing bid and asked prices on the date of determination as reported in The Wall Street Journal or such other source as the Board deems reliable.

(iii) In the absence of any of the foregoing, the Fair Market Value will be determined by the Board in good faith in compliance with applicable laws and in a manner that complies with Sections 409A of the Code.

(iv) Notwithstanding the foregoing, for any Offering that commences on the IPO Date (as defined in Section 16 below), the Fair Market Value of the shares of Common Stock on the Offering Date will be the price per share at which shares are first sold to the public in the Company’s initial public offering as specified in the final prospectus for that initial public offering.

(a) An eligible employee may become a participant in the Plan pursuant to an Offering by delivering a participation agreement to the Company within the time specified in the Offering, in such form as the Company provides. Each such agreement shall authorize payroll deductions of up to the maximum percentage (in whole percentages only) specified by the Board or the Committee of such employee’s Earnings during the Offering. “Earnings” are defined as an employee’s wages (including amounts thereof elected to be deferred by the employee, that would otherwise have been paid, under any arrangement established by the Company that is intended to comply with Section 125, Section 132(f)(4), Section 401(k), Section 402(h) or Section 403(b) of the Code or that provides non-qualified deferred compensation), which shall include overtime pay, incentive pay, and commissions, but shall exclude bonuses, profit sharing or other remuneration paid directly to the employee, the cost of employee benefits paid for by the Company or an Affiliate, education or tuition reimbursements, imputed income arising under any group insurance or benefit program, traveling expenses, business and moving expense reimbursements, income received in connection with stock options, contributions made by the Company or an Affiliate under any employee benefit plan, and similar items of compensation, as determined by the Board or the Committee. The payroll deductions made for each participant shall be credited to an account for such participant under the Plan and shall be deposited with the general funds of the Company except where applicable law requires a deposit with a third party. If permitted in the Offering, a Participant may begin such deductions with the first payroll occurring on or after the Offering Date (or, in the case of a payroll date that occurs after the end of the prior Offering but before the Offering Date of the next new Offering, such deductions from payroll will be included in the new Offering). If permitted in the Offering, a participant may thereafter reduce (including to zero) or increase such payroll deductions. A participant may make additional payments into his or her account only if specifically provided for in the Offering and only if the participant has not had the maximum amount withheld during the Offering.

(b) At any time during an Offering, a participant may terminate his or her payroll deductions under the Plan and withdraw from the Offering by delivering to the Company a notice of withdrawal in such form as the Company provides. Such withdrawal may be elected at any time prior to the end of the Offering except as provided by the Board or the Committee in the Offering with respect to any deadline for withdrawing before a Purchase Date. Upon such withdrawal from the Offering by a participant, the Company shall distribute to such participant all of his or her accumulated payroll deductions (reduced to the extent, if any, such deductions have been used to acquire stock for the participant) under the Offering, without interest, and such participant’s interest in that Offering shall be automatically terminated. A participant’s withdrawal from an Offering will have no effect upon such participant’s eligibility to participate in any other Offerings under the Plan but such participant will be required to deliver a new participation agreement in order to participate in subsequent Offerings under the Plan.

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(c) Purchase Rights granted pursuant to any Offering under the Plan shall terminate immediately upon cessation of any participating employee’s employment with the Company and any designated Affiliate, for any reason, and the Company shall distribute to such terminated employee all of his or her accumulated payroll deductions (reduced to the extent, if any, such deductions have been used to acquire stock for the terminated employee), under the Offering, without interest.

(d) Purchase Rights granted under the Plan shall not be transferable by a participant otherwise than by will or the laws of descent and distribution, or by a beneficiary designation as provided in paragraph 14 and, otherwise during his or her lifetime, shall be exercisable only by the person to whom such Purchase Rights are granted.

(a) On each Purchase Date specified therefor in the relevant Offering, each participant’s accumulated payroll deductions and other additional payments specifically provided for in the Offering (without any increase for interest) shall be applied to the purchase of whole shares of stock of the Company, up to the maximum number of shares permitted pursuant to the terms of the Plan and the applicable Offering, at the purchase price specified in the Offering. No fractional shares shall be issued upon the exercise of Purchase Rights granted under the Plan. The amount, if any, of accumulated payroll deductions remaining in each participant’s account after the purchase of shares which is less than the amount required to purchase one share of stock on the final Purchase Date of an Offering shall be held in each such participant’s account for the purchase of shares under the next Offering under the Plan, unless such participant withdraws from such next Offering, as provided in subparagraph 7(b), or is no longer eligible to be granted Purchase Rights under the Plan, as provided in paragraph 5, in which case such amount shall be distributed to the participant after such final Purchase Date, without interest. The amount, if any, of accumulated payroll deductions remaining in any participant’s account after the purchase of shares which is equal to the amount required to purchase whole shares of stock on the final Purchase Date of an Offering shall be distributed in full to the participant after such Purchase Date, without interest.

(b) No Purchase Rights granted under the Plan may be exercised to any extent unless the shares to be issued upon such exercise under the Plan (including Purchase Rights granted thereunder) are covered by an effective registration statement pursuant to the Securities Act of 1933, as amended (the “Securities Act”), and the Plan is in material compliance with all state, foreign and other securities and other laws applicable to the Plan. If on a Purchase Date in any Offering hereunder the Plan is not so registered or in such compliance, no Purchase Rights granted under the Plan or any Offering shall be exercised on such Purchase Date, and the Purchase Date shall be delayed until the Plan is subject to such an effective registration statement and such compliance, except that the Purchase Date shall not be delayed more than twelve (12) months and the Purchase Date shall in no event be more than twenty-seven (27) months from the Offering Date. If on the Purchase Date of any Offering hereunder, as delayed to the maximum extent permissible, the Plan is not registered and in such compliance, no Purchase Rights granted under the Plan or any Offering shall be exercised and all payroll deductions accumulated during the Offering (reduced to the extent, if any, such deductions have been used to acquire stock) shall be distributed to the participants, without interest.

(a) During the terms of the Purchase Rights granted under the Plan, the Company shall keep available at all times the number of shares of stock required to satisfy such Purchase Rights.

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(b) The Company shall seek to obtain from each federal, state, foreign or other regulatory commission or agency having jurisdiction over the Plan such authority as may be required to grant of Purchase Rights and issue and sell shares of stock upon exercise of the Purchase Rights granted under the Plan. If, after reasonable efforts, the Company is unable to obtain from any such regulatory commission or agency the authority which counsel for the Company deems necessary for the grant of Purchase Rights or the lawful issuance and sale of stock under the Plan, the Company shall be relieved from any liability for failure to grant Purchase Rights and/or to issue and sell stock upon exercise of such Purchase Rights.

Proceeds from the sale of stock pursuant to Purchase Rights granted under the Plan shall constitute general funds of the Company.

A participant shall not be deemed to be the holder of, or to have any of the rights of a holder with respect to, any shares subject to Purchase Rights granted under the Plan unless and until the participant’s shareholdings acquired upon exercise of Purchase Rights under the Plan are recorded in the books of the Company.

(a) If any change is made in the stock subject to the Plan, or subject to any Purchase Rights granted under the Plan, due to a change in corporate capitalization and without the receipt of consideration by the Company (through reincorporation, stock dividend, stock split, reverse stock split, combination or reclassification of shares, other than the conversion of any convertible securities of the Company), the Plan shall be appropriately adjusted in the class(es) and maximum number of securities subject to the Plan pursuant to subsection 3(a), and the outstanding Purchase Rights shall be appropriately adjusted in the class(es) and number of securities and price per share of stock subject to such outstanding Purchase Rights. Such adjustments shall be made by the Board, the determination of which shall be final, binding and conclusive.

(b) In the event of: (1) a dissolution, liquidation or sale of all or substantially all of the securities or assets of the Company, (2) a merger or consolidation in which the Company is not the surviving corporation or (3) a reverse merger in which the Company is the surviving corporation but the shares of Common Stock outstanding immediately preceding the merger are converted by virtue of the merger into other property, whether in the form of securities, cash or otherwise, then any surviving corporation may assume outstanding Purchase Rights or substitute similar Purchase Rights for those under the Plan. In the event that no surviving corporation assumes outstanding Purchase Rights or substitutes similar rights therefor, participants’ accumulated payroll deductions shall be used to purchase Common Stock immediately prior to the transaction described above and the participants’ Purchase Rights under the ongoing Offering shall terminate immediately following such purchase.

(a) The Board at any time, and from time to time, may amend the Plan. However, except as provided in paragraph 12 relating to adjustments upon changes in stock, no amendment shall be effective unless approved by the stockholders of the Company within twelve (12) months before or after the adoption of the amendment, where the amendment will:

(i) Increase the number of shares reserved for Purchase Rights under the Plan;

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(ii) Modify the provisions as to eligibility for participation in the Plan (to the extent such modification requires stockholder approval in order for the Plan to obtain employee stock purchase plan treatment under Section 423 of the Code or to comply with the requirements of Rule 16b-3 promulgated under the Securities Exchange Act of 1934, as amended (“Rule 16b-3”)); or

(iii) Modify the Plan in any other way if such modification requires stockholder approval in order for the Plan to obtain employee stock purchase plan treatment under Section 423 of the Code or to comply with the requirements of Rule 16b-3.

It is expressly contemplated that the Board may amend the Plan in any respect the Board deems necessary or advisable to provide eligible employees with the maximum benefits provided or to be provided under the provisions of the Code and the regulations promulgated thereunder relating to employee stock purchase plans and/or to bring the Plan and/or Purchase Rights granted under it into compliance therewith.

(b) Rights and obligations under any Purchase Rights granted before amendment of the Plan shall not be impaired by any amendment of the Plan, except with the consent of the person to whom such Purchase Rights were granted, or except as necessary to comply with any laws or governmental regulations, or except as necessary to ensure that the Plan and/or Purchase Rights granted under the Plan comply with the requirements of Section 423 of the Code.

(a) A participant may file a written designation of a beneficiary who is to receive shares and cash, if any, from the participant’s account under the Plan in the event of such participant’s death subsequent to the end of an Offering but prior to delivery to the participant of such shares and cash. In addition, a participant may file a written designation of a beneficiary who is to receive any cash from the participant’s account under the Plan in the event of such participant’s death during an Offering.

(b) Such designation of beneficiary may be changed by the participant at any time by written notice. In the event of the death of a participant and in the absence of a beneficiary validly designated under the Plan who is living at the time of such participant’s death, the Company shall deliver such shares and/or cash to the executor or administrator of the estate of the participant, or if no such executor or administrator has been appointed (to the knowledge of the Company), the Company, in its sole discretion, may deliver such shares and/or cash to the spouse or to any one or more dependents or relatives of the participant, or if no spouse, dependent or relative is known to the Company, then to such other person as the Company may designate.

(a) The Board in its discretion, may suspend or terminate the Plan at any time. No Purchase Rights may be granted under the Plan while the Plan is suspended or after it is terminated.

(b) Rights and obligations under any Purchase Rights granted while the Plan is in effect shall not be altered or impaired by suspension or termination of the Plan, except as expressly provided in the Plan or with the consent of the person to whom such Purchase Rights were granted, or except as necessary to comply with any laws or governmental regulation, or except as necessary to ensure that the Plan and/or Purchase Rights granted under the Plan comply with the requirements of Section 423 of the Code.

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The Plan shall become effective on the IPO Date, provided that it has been adopted by the Board prior to such time, but no Purchase Rights shall be exercised under the Plan unless and until the Plan has been approved by the stockholders of the Company within twelve (12) months before or after the date the Plan is adopted by the Board. “IPO Date” shall mean the date of the underwriting agreement between the Company and the underwriter(s) managing the initial public offering of the Common Stock, pursuant to which the Common Stock is priced for the initial public offering.

The laws of the State of California shall govern all questions concerning the construction, validity and interpretation of the Plan, without regard to such state’s conflict of law rules.

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