Exhibit 99.3

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS OF

ENDOLOGIX, INC.

On October 26, 2015, Endologix entered into the merger agreement with TriVascular. Under the terms of the merger agreement, Endologix agreed to acquire all of TriVascular’s outstanding capital stock through a merger of a direct, wholly owned subsidiary of Endologix with TriVascular. The consummation of the merger will provide the newly combined company with a strategic competitive advantage in research and development and product development expansion, retaining existing customers and expanding its customer base. The merger was completed on February 3, 2016. At the effective time of the Merger, each outstanding share of common stock of TriVascular (other than shares for which appraisal rights under Delaware law were properly exercised) was converted into the right to receive (i) $0.34 in cash and (ii) 0.631 shares of Endologix common stock (the “Merger Consideration”). Endologix paid approximately $108.1 million in preliminary aggregate consideration, consisting of approximately $7.3 million in cash and 13.6 million shares of Endologix common stock. On November 2, 2015 Endologix issued $125 million in 3.25% Convertible Senior Notes in connection with this transaction.

The following unaudited pro forma condensed combined statements of operations for the nine months ended September 30, 2015, and the year ended December 31, 2014, are presented as if the merger had been completed on January 1, 2014. The unaudited pro forma condensed combined balance sheet as of September 30, 2015, is presented as if the merger had been completed on September 30, 2015. The unaudited pro forma condensed combined financial statements presented below are derived from the historical consolidated financial statements of Endologix and the historical consolidated financial statements of TriVascular. The historical consolidated financial statements of Endologix and TriVascular are presented in accordance with GAAP.

As described in the accompanying notes, the unaudited pro forma condensed combined financial statements have been prepared using the acquisition method of accounting under GAAP and the regulations of the SEC. GAAP requires that one of the companies in the merger be designated as the accounting acquirer for the purposes of applying the acquisition method of accounting under ASC 805. Endologix is the accounting acquirer.

The historical consolidated financial statements have been adjusted in the unaudited pro forma condensed combined financial statements to give effect to the pro forma events that are: (i) directly attributable to the merger; (ii) factually supportable; and (iii) with respect to the unaudited pro forma condensed combined statements of operations, expected to have a continuing impact on the combined results. The unaudited pro forma condensed combined statements of operations exclude non-recurring items that are directly related to the merger, including, but not limited to: (1) merger related legal and advisory fees; and (2) the impact of inventory pro forma adjustments on cost of goods sold. Additionally, certain pro forma reclassification adjustments have been made to the historical consolidated financial statements of TriVascular in order to conform its financial statement classification policies to those applied by Endologix.

Because the acquisition method of accounting is dependent upon certain valuations and other studies that must be prepared as of the closing date of the merger, there currently is not sufficient information for a definitive measurement; therefore, the unaudited pro forma condensed combined financial statements are preliminary. In determining the preliminary estimate of fair values of TriVascular’s assets that have been acquired and liabilities that have been assumed, Endologix used publically available benchmarking information, as well as a variety of other assumptions, including market participant assumptions. Differences between these preliminary estimates and the final acquisition accounting will occur and these differences could have a material impact on the accompanying unaudited pro forma condensed combined financial statements and the combined future results of operations and financial position.

The unaudited pro forma condensed combined financial statements do not give effect to the potential impact of any anticipated synergies, operating efficiencies or cost savings that may result from the merger or any integration costs. The unaudited pro forma condensed combined financial statements are provided for illustrative purposes only and do not purport to represent what the actual consolidated results of operations or the consolidated financial position of the newly combined company would have been had the merger occurred on the dates assumed, nor are they necessarily indicative of future consolidated results of operations or consolidated financial position.

ENDOLOGIX, INC.

UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET

AS OF SEPTEMBER 30, 2015

(dollars in thousands)

ENDOLOGIX, INC.

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

FOR THE NINE MONTHS ENDED SEPTEMBER 30, 2015

(dollars and weighted average shares outstanding in thousands, except per share amounts)

ENDOLOGIX, INC.

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

FOR THE YEAR ENDED DECEMBER 31, 2014

(dollars and weighted average shares outstanding in thousands, except per share amounts)

ENDOLOGIX, INC.

NOTES TO THE UNAUDITED PRO FORMA COMBINED FINANCIAL STATEMENTS

FOR THE YEAR ENDED DECEMBER 31, 2014 AND

THE NINE MONTHS ENDED SEPTEMBER 30, 2015

(in thousands except per share amounts)

1. Basis of Presentation

The unaudited pro forma condensed combined financial statements have been prepared in accordance with Article 11 of Regulation S-X. The historical consolidated financial information of Endologix and TriVascular has been adjusted to give effect to transactions that are (i) directly attributable to the merger, (ii) factually supportable and (iii) with respect to the unaudited pro forma condensed combined statement of operations, expected to have a continuing impact on the operating results of the combined company. The historical consolidated financial statements of Endologix and TriVascular are presented in accordance with GAAP.

The unaudited pro forma condensed combined balance sheet as of September 30, 2015 was prepared using the historical unaudited consolidated balance sheets of Endologix and TriVascular as of September 30, 2015, and presents the combined financial position of Endologix and TriVascular as if the merger occurred on September 30, 2015. The unaudited pro forma condensed combined statements of operations for the nine months ended September 30, 2015 and the year ended December 31, 2014 assume that the merger was consummated on January 1, 2014.

Endologix’s historical consolidated financial information for the year ended December 31, 2014 and as of and for the nine months ended September 30, 2015 is derived from Endologix’s Form 10-K and Form 10-Q filed with the SEC on March 2, 2015 and October 30, 2015, respectively. The historical consolidated financial information for TriVascular for the year ended December 31, 2014 and as of and for the nine months ended September 30, 2015 is derived from TriVascular’s Form 10-K and Form 10-Q filed with SEC on March 9, 2015 and November 9, 2015, respectively.

The unaudited pro forma condensed combined statements of operations for the nine months ended September 30, 2015, and the year ended December 31, 2014, have not been adjusted for the following estimated amounts that are expected to have a one-time impact on the pro forma combined loss from continuing operations in the 12 months following the merger (in thousands):

No income tax effect has been provided for the pro forma adjustments to income (loss) before income taxes, as it is anticipated that the adjustments will be in entities with a deferred tax valuation allowance.

The unaudited pro forma condensed combined financial statements have been prepared using the acquisition method of accounting in accordance with the business combination accounting guidance as provided in Accounting Standards Codification 805, Business Combinations, with Endologix treated as the accounting acquirer.

The unaudited pro forma condensed combined financial statements should be read in conjunction with:

2. Significant Accounting Policies

The accounting policies used in the preparation of the unaudited pro forma condensed combined financial statements are those set out in Endologix’s historical audited financial statements as of and for the year ended December 31, 2014. Endologix’s management has determined that no significant adjustments are necessary to conform TriVascular’s financial statements to the accounting policies used by Endologix in the preparation of the unaudited pro forma condensed combined financial information. Certain reclassifications have been reflected in the pro forma adjustments to conform TriVascular’s presentation to that of Endologix in the pro forma balance sheet and statement of operations. Specifically, reclassifications have been made to present a) TriVascular’s clinical and regulatory expenses apart from research and development expenses; b) TriVascular’s sales and marketing expenses apart from general and administrative expenses; and c) TriVascular’s interest income apart from other income (expense). These reclassifications were prepared to conform to Endologix’s presentation of operating expenses in the statement of operations. These reclassifications were prepared using the account descriptions in TriVascular’s underlying accounting records and have no effect on previously reported total assets, total liabilities and stockholders’ equity, or income from continuing operations of Endologix or TriVascular. The unaudited pro forma condensed combined financial statements may not reflect all reclassifications necessary to conform TriVascular’s presentation to that of Endologix, due to limitations on the availability of information as of the date of this filing. Accounting policy differences and additional reclassification adjustments may be identified as more information becomes available.

3. Calculation of Merger Consideration and Preliminary Allocation

The estimated fair value of the merger consideration transferred on the closing date includes cash consideration and the fair value of the equity transferred in accordance with the merger agreement. The aggregate merger consideration paid to the stockholders of TriVascular in accordance with the merger agreement consisted of 19.999% of Endologix common stock outstanding as of the effective time of the merger, estimated to be approximately $100.8 million, and approximately $7.3 million in cash consideration. The cash portion of the merger consideration is based upon several underlying computations set forth in the merger agreement. The separate components of the cash merger consideration comprise items (2) through (7) below, and are presented together with the total stock consideration as follows (in thousands):

Preliminary Allocation of the Merger Consideration

Under the acquisition method of accounting, the identifiable assets acquired and liabilities assumed of TriVascular are recorded at the acquisition date fair values and added to those of Endologix. The pro forma adjustments are preliminary and based on estimates of the fair value and useful lives of the assets acquired and liabilities assumed and have been prepared to illustrate the estimated effect of the merger. The final determination of the allocation of the merger consideration upon the consummation of the merger will be based on TriVascular’s net assets acquired as of that date and will depend on a number of factors, which cannot be predicted with any certainty at this time. The allocation of the merger consideration may change materially based on the receipt of more detailed information. Therefore, the actual allocations will differ from the pro forma adjustments presented. The allocation is dependent upon certain valuation and other studies that have not yet been completed. Accordingly, the pro forma allocation of the merger consideration is subject to further adjustment as additional information becomes available and as additional analyses and final valuations are completed. There can be no assurances that these additional analyses and final valuations will not result in significant changes to the estimates of fair values set forth below.

The following table sets forth a preliminary allocation of the estimated merger consideration to the identifiable tangible and intangible assets acquired and liabilities assumed of TriVascular based on TriVascular’s September 30, 2015 balance sheet (in thousands):

The preliminary identifiable intangible assets acquired consist of anticipated intangibles derived from developed technology, in-process technology and customer related assets. The amortization related to the amortizable identifiable intangible assets acquired is reflected as a pro forma adjustment in the unaudited pro forma condensed combined statements of operations, as further described in Note 5(a). The identifiable intangible assets and related amortization are preliminary and are based on management’s estimates after consideration of similar transactions. As discussed above, the amount that will ultimately be allocated to identifiable intangible assets and liabilities, and the related amount of amortization, may differ materially from this preliminary allocation. In addition, the periods impacted by the amortization will ultimately be based upon the periods in which the associated economic benefits or detriments are expected to be derived or, where appropriate, based on the use of a straight-line method. Therefore, the amount of amortization following the merger may differ significantly between periods based upon the final fair value assigned, and amortization methodology used for each identifiable intangible asset.

Deferred tax assets and liabilities have not been established for the pro forma adjustments above as it is anticipated that the adjustments will be in entities with a deferred tax valuation allowance.

Goodwill represents the excess of the merger consideration over the fair value of the underlying net assets acquired. Goodwill is not amortized but instead is reviewed for impairment at least annually, absent any indicators of impairment. Any goodwill ultimately recognized in the merger is not expected to be deductible for tax purposes.

4. Notes to Unaudited Pro Forma Condensed Combined Balance Sheet

The qualitative factors that are expected to lead to goodwill being recognized in the acquisition include an expanded complement of trained sales personnel, access to new geographies, assembled work force including unpatented technical expertise that is not separable from the assembled workforce, and expected synergies from combining operations of Endologix and TriVascular.

TriVascular had no accrued interest as of September 30, 2015. Refer to Note 5(c) for additional details regarding the 3.25% Convertible Senior Notes.

Component”) and a separate component for which stockholder approval would be necessary to authorize the requisite number of shares to effect share settlement (the “Derivative Liability Component”). In accordance with ASC 815-40, the Equity Component is classified as permanent equity and the Derivative Liability Component is classified as liability which must be marked to market each period.

The allocation of proceeds to the conversion feature results in a $32.3 million discount on the Senior Convertible Notes which reduces their carrying value from $125 million to $92.7 million. The discount is amortized over the term of the Senior Convertible Notes such that total effective interest expense approximates 10.9%. For purposes of allocating the $125 million proceeds, Endologix separated the Senior Convertible Notes into two portions: a portion for which, at September 30, 2015 on a pro forma basis, authorized shares exist in sufficient quantity to fully cover the conversion feature (Portion A), and a second portion that, at September 30, 2015 has no authorized shares reserved to cover the conversion feature on a pro forma basis (Portion B). The allocation was performed by first determining the fair value of the Derivative Liability Component. The amount allocated to the Derivative Liability Component was then deducted from Portion B to arrive at residual amount, which was allocated to the carrying value of Portion B. Next, the fair value of the Equity Component was determined and allocated directly to additional paid-in capital, with the residual amount allocated to Portion A.

For purposes of the unaudited pro forma condensed combined balance sheet as of September 30, 2015 only, Endologix has estimated that the associated financing fees will total $3.7 million. Of this amount, $2.9 million are estimated to be capitalized and $0.8 million are estimated to be allocable to the Equity Component. Fees allocable to the Equity Component are regarded as equity issuance costs and accounted for as a reduction to additional paid in capital.

5. Notes to Unaudited Pro Forma Condensed Combined Statements of Operations

The adjustment for the amortization of the identifiable intangible assets is as follows:

The table below indicates the estimated fair value of each of the identifiable intangible assets and estimated useful life of each (in thousands):

Developed technology expected to be acquired in the merger consists primarily of the Ovation System, TriVascular’s stent graft platform and associated surgical techniques approved in the U.S, Europe, and certain countries in Asia for the treatment of AAA through minimally invasive EVAR. For the purposes of estimating the fair value of the developed technology in this unaudited pro forma condensed combined financial information, the Company compiled publicly available purchase allocation data for comparable acquisitions in the same industry and developed a range in relation to the median proportion of total purchase consideration assigned to technology based intangibles in those comparable transactions. A point within this range of percentages allocable to technology based intangibles was then selected based on company specific factors such as the significance of TriVascular’s tangible assets in relation to that of the comparable companies used. This selected percentage was then divided between developed and in-process technologies based on a qualitative assessment of the relative market potential of TriVascular’s approved and in-process technologies. Such assessment was necessarily limited to information available at the time and is subject to change as more information is made available. The respective percentages selected for developed and in-process technology were then applied to the estimated Merger Consideration to arrive at the estimated fair value for both of the technology based intangibles. The estimated useful life for developed technology was determined in reference to a variety of inputs, including the status of development of TriVascular’s next generation solutions, the extent to which TriVascular’s existing developed technology migrates to such future solutions, the estimated status of development of competing technologies, and the results of a benchmarking analysis in which useful lives assigned to developed technology associated with comparable transactions was compiled.

In-process technology acquired in the Merger consists primarily of the Ovation Alto platform, TriVascular’s next generation aortic body that together with the next generation iliac limbs make up the Ovation Alto stent graft, and other potential platform applications such as those applicable to the treatment of thoracic aneurysms. Endologix expects that the remaining cash requirements to obtain regulatory approval relate to research and development and clinical studies for Ovation Alto and is estimated to be approximately $5 to $10 million. In-process technology will be accounted for as an indefinite-lived intangible asset until the underlying projects are completed or abandoned.

Each 1/8% increase in the stated interest rate on the Senior Convertible Notes would result in a $0.1 million increase in interest expense for the nine months ended September 30, 2015. The following table shows the effect of a change in estimated all-in effective interest rate and the resulting discount on the Senior Convertible Notes at inception and interest expense for the nine months ended September 30, 2015 (dollars in thousands):

Each 1/8% increase in the stated interest rate on the Senior Convertible Notes would result in a $0.2 million increase in interest expense for the year ended December 31, 2014. The following table shows the effect of a change in estimated all-in effective interest rate and the resulting discount on the Senior Convertible Notes at inception and interest expense for the year ended December 31, 2014 (dollars in thousands):