Your question is a bit vague, but I'm going to assume that you are asking how important the debate over the azymes (i.e., the use of leavened versus unleavened bread during the Eucharist) was in the events that caused the schism of 1054.

From the research I have done, I can say that the azymes was the main religious issue separating Rome and Constantinople during this time period, at least in Southern Italy (one of the few places where there were substantial numbers of Greeks and Latins in close contact at this time). I come to this conclusion mainly through the hagiographic and Norman chronicle sources of this time period. There aren't a whole lot of mentions of religious conflict in these sources, but when they do occur, they most frequently comment on the azymes, rather than the filioque or other problems, such as papal authority.

Sources: Italo-Greek Hagiography (such as the Life of St. Cyprian, the Life of John Theristis, and the Life of St. Luke), Norman Chronicles (mainly Amatus of Montecassino and Geoffrey Malaterra). I believe that Runciman discusses this in his book on the schism as well. I can also provide a journal article of mine that was recently published on the subject of religious conflict in Southern Italy in the 12th century.