SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

SCHEDULE 13G

(Rule 13d-102)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO

RULES 13d-1(b), (c) AND (d) AND AMENDMENTS THERETO FILED

PURSUANT TO RULE 13d-2

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Name of Issuer)

(Title of Class of Securities)

(CUSIP Number)

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

x    Rule 13d-1(b)

x    Rule 13d-1(c)

¨    Rule 13d-1(d)

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SCHEDULE 13G

This Schedule 13G (this “Schedule 13G”) is being filed on behalf of Highland Crusader Offshore Partners, L.P., a Bermuda limited partnership (the “Crusader Fund”), Highland Crusader Fund GP, L.P., a Delaware limited partnership and general partner of the Crusader Fund (the “Crusader GP”), Highland Crusader GP LLC, a Delaware limited liability company and general partner of the Crusader GP (the “Crusader LLC”), Highland Capital Management, L.P., a Delaware limited partnership (“Highland Capital”), Strand Advisors, Inc., a Delaware corporation (“Strand”), and James D. Dondero (collectively, the “Reporting Persons”).

James D. Dondero is the President of Strand. Strand is the general partner of Highland Capital. Highland Capital serves as the advisor to the Crusader Fund, among other funds and managed accounts and sole member of the Crusader LLC. This Schedule 13G relates to common shares without par value (the “Common Shares”), of Angiotech Pharmaceuticals, Inc., a corporation organized under the Business Corporations Act of the Province of British Columbia (the “Issuer”), held by the Crusader Fund.

  Angiotech Pharmaceuticals, Inc.

  1618 Station Street

  Vancouver, British Columbia, Canada VGA 1B6

  For all Filers:

  300 Crescent Court, Suite 700

  Dallas, Texas 75201

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  Common Shares, without par value.

  034918201

As advisor to the Crusader Fund and sole member of the Crusader LLC, Highland Capital and Strand may be deemed the beneficial owners of the 1,547,750 Common Shares held by the Crusader Fund.

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Mr. Dondero may be deemed the beneficial owner of the 1,547,750 Common Shares held by the Crusader Fund as President of Highland Capital.

Mr. Dondero may be deemed the beneficial owner of 12.3% of the outstanding Common Shares. This percentage was determined by dividing 1,547,750, the number of Common Shares held directly by the Crusader Fund, by 12,556,673, which is the number of Common Shares outstanding according to the Issuer’s Quarterly Report on Form 10-Q for the quarterly period ended on March 31, 2012 filed with the Securities and Exchange Commission on May 15, 2012.

Inapplicable.

Inapplicable.

Strand is the parent holding company of Highland Capital, and Mr. Dondero is the control person of Strand.

Inapplicable.

Inapplicable.

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For the Crusader Fund, the Crusader GP and the Crusader LLC:

By signing below each of the Reporting Persons certifies that, to the best of such person’s knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

For Highland Capital, Strand and Mr. Dondero:

By signing below each of the Reporting Persons certifies that, to the best of such person’s knowledge and belief, the securities referred to above were acquired and held in the ordinary course of business and were not acquired and were not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

Joint Filing Agreement, dated June 12, 2012, between the Crusader Fund, the Crusader GP, the Crusader LLC, Highland Capital, Strand, and James D. Dondero.

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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: June 12, 2012

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Exhibit 99-1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned agree to the joint filing on behalf of each of them of a Statement on Schedule 13G (including any and all amendments thereto) with respect to the common shares without par value, of Angiotech Pharmaceuticals, Inc., and further agree that this Joint Filing Agreement shall be included as an Exhibit to such joint filings.

The undersigned further agree that each party hereto is responsible for the timely filing of such Statement on Schedule 13G and any amendments thereto, and for the accuracy and completeness of the information concerning such party contained therein; provided, however, that no party is responsible for the accuracy or completeness of the information concerning any other party, unless such party knows or has reason to believe that such information is inaccurate.

This Joint Filing Agreement may be signed in counterparts with the same effect as if the signature on each counterpart were upon the same instrument.

[Signature Page Follows]

IN WITNESS WHEREOF, the undersigned have executed this Agreement as of June 12, 2012.