General Discussion

28 US CODE 1253. Direct appeals from decisions of three-judge courts
Except as otherwise provided by law, any party may appeal to the Supreme Court from an order granting or denying, after notice and hearing, an interlocutory or permanent injunction in any civil action, suit or proceeding required by any Act of Congress to be heard and determined by a district court of three judges.

Appeals of three judge district court decisions go directly to the Supreme Court, not he court of appeals. And Supreme Court review is mandatory -- in other words, it does not require the Court to grant certiorari before hearing the case.