Hello everyone! I'm hoping that someone (perhaps a M2-4) will have the answer to this question, but first the background. On Thursday night, we rushed my grandfather to the ER because he could not breathe. He is a very spry 78-year-old guy...goes dancing 1-4 times per week with his girlfriend. (They're like teenagers! ) We found out Friday that he had bilateral pulmonary embolism, plus they found a third blood clot in his leg. The pulmonologist said they considered putting in a filter, but decided against it. The reasoning was that it has only been proven to be effective after the second PE. WHY???? From what I read in my boyfriend's pulmonology books (he is in PA school), the mortality rate is 67% from PE. First, why would they wait for a second PE when the mortality rate is so high? And second, what would change in the blood vessels after the second PE that would make the filter effective? If anyone has any information, I would really appreciate it. I am very confused by this. Thank you very much, Tammy p.s. My grandfather is doing very well and is expected to come home by the end of the week.