The four notes that conclude "Anakin's Theme" are nearly identical to the opening few notes of "The Imperial March", sharing pitches, intervals, and contour, and differing only in rhythm (and only slightly at that) and character ("Anakin's Theme", of course, doesn't have the ominous power that "The Imperial March" has).
This connection is made very clear during the end credits of The Phantom Menace, in which John Williams repeats those last few notes several times in a row, as if to say, "In case you missed the foreshadowing, here it is again!" This can be heard in the YouTube video below around 7:45.
The Music of Star Wars
These posts will help focus and develop my analyses of John Williams' film scores.