J.W.
Let me add support to the great information Lee and others have already provided. TPA is a wonder drug for heart attack and stroke victims and is administered in the emergency room within crucial hours to save hearts and brains and lives!
I used to work for the American Heart Association National HDQ in the American Stroke Association division so I studied a lot about TPA. The most important thing here is to get rid of that clot before it gets rid of you! I'm glad you're on clot-busting medication now, but apparently it is not able to do the whole job which is why you're getting TPA.
By all means, educate yourself, but be sure you do so from reputable sources. There are many, many "health care scare" sites on the internet that are more strong opinions than they are research-based information. If you use the internet to research this or any other procedure or illness, PLEASE be sure you're going to sites that are backed up by people and organizations that know what they're talking about! Otherwise, you might as well get your health info from tabloids. Blessings to you!