If you had a filter put in prior to surgery some time ago, and left it in, you should check to find out what kind of filter it was - there is a recall.
http://www.nbcnews.com/health/healt...ep-selling-problem-blood-clot-filters-n488166
http://www.nbcnews.com/health/healt...ep-selling-problem-blood-clot-filters-n488166