Exhibit 99.1 Explanation of Responses (1) Pursuant to a Note Purchase Agreement, dated as of June 25, 2004, by and among Micro Therapeutics, Inc. (the "Company"), Warburg, Pincus Equity Partners, L.P., a Delaware limited partnership (together with...Note Purchase Agreement • August 19th, 2004 • Warburg Pincus & Co • Surgical & medical instruments & apparatus
