Hillary Clinton's recent blood clot will have an affect on her political future. It is no secret that she has presidential aspirations, and it will indeed affect whether people support her or not. Nobody wants to vote for a sickly president. If something happens to them, then chaos and uncertainty will happen.
It's not that the blood clot itself will greatly affect her future, as what the blood clot signifies, which is that she is aging and health has become a legitimate concern. When a big health problem like this happens, people become more doubtful about the trust they place in a politician.
Of course it won't as long as it is treated and she recovers completely. What is really pertinent to this discussion is her age and of course gender. Were she to be elected president in four years she would be at the top of the age range of presidents however this particular incident has no bearing on her overall health or her fitness to be president. This is an acute illness resulting from an accidental fall that is completely treatable. Presidents are not paragons of health. FDR was crippled from polio, Eisenhower had Crohn's Disease, and Reagan served as President after being shot. This has no bearing on her ability to be a President.
As Hillary is aging, events such as this could become a common occurrence, however the blood clot itself does not appear to be a problem which could hinder her future in politics. According to various news sources, she suffered a concussion after a stomach virus and this type of blood clot, which isn't an aneurysm, is something that eighty percent recover from. Based on this statistic, I believe the blood clot itself will NOT be something that will prohibit her from running for president, although there are other things that may.