“My name is DeWitt. I’m a neurosurgeon in Charleston, South Carolina,” a velvety male voice announced. I cocked the telephone receiver under my chin as I grabbed the chart Autumn handed to me.
“I have just operated on your patient, George Magnusson. He had a large subdural hematoma from a fall that happened a few days ago.” The surgeon spoke in a slow, subtle Southern accent. He continued:
“The reason I am calling is that you’ve had this man on blood thinners for several years now for a pulmonary embolus and deep vein thrombosis he suffered after a motor vehicle accident.”
I glanced at Mr. Magnusson’s problem list.
“Yes, in 2001,” I replied.
“Right,” he continued, “but he has a Greenfield filter, so he is protected from pulmonary embolization.” After a slight pause he continued in a restrained, low voice:
“I don’t believe one usually continues the warfarin under those circumstances. I had to reverse it for the surgery and will be leaving him off it while he’s here, obviously. But I would suggest you discuss the risks and benefits with him when he returns home.”
“What was his prothrombin time?” I asked.
“It was therapeutic. And I expect him to make a full recovery, fortunately for all of us,” he added. “He should be back in your area next week.”
The telephone conversation left me thinking.
George Magnusson had taken his blood thinner faithfully for ten years and had hardly ever been out of the therapeutic range. He was fairly healthy otherwise, and I seldom saw him during the three or four years he had been my patient. When I first met him, I had not questioned his need for chronic anticoagulation.
One school of thought is that patients with a definite trigger for a blood clot, such as a major fracture, can be taken off blood thinners after three to six months. Another viewpoint is that patients with a history of massive clots are better left on their blood thinners indefinitely.
Had I failed George Magnusson by keeping him on warfarin and subjecting him to an unnecessary risk of bleeding as he was getting older? After all, his clots happened after a major car accident with multiple fractures.
In my mind I went over what I remembered about inferior vena cava filters. I had very little experience with them, but never thought of them as a replacement for anticoagulation. At best they only reduce the risk that a blood clot would separate from its location in a leg and travel to the lungs, but a person who is at risk for blood clots in the legs could still develop them.
My most trusted online database stated: “Because patients with IVC filters are at risk for IVC thrombosis, insertion site thrombosis, and recurrence of the initial thromboembolic event, continued use of anticoagulants when there are no contraindications is prudent.”
When George and Ellen Magnusson returned from their winter vacation near Hilton Head, South Carolina, they both looked tired. George’s thick, gray hair had been shaved on one side of his head for the operation.
I went over the pros and cons of staying on blood thinners after trauma-related clots like George’s. Especially Ellen looked reserved.
“Dr. DeWitt was very sure blood thinners weren’t necessary,” she said.
“It’s a judgment call,” I answered. “Why don’t we get a hematology consultation? I’d like to hear what someone like Dr. Hertzog thinks about your situation.”
Ellen and George left the office and we agreed to talk again after the hematology consultation.
This morning I got a call from the Emergency Room. George just came in with a massive clot from his calf all the way up to his groin.
I guess we won’t need that hematology consult, after all.
A Country Doctor Writes: 
I realize it has been awhile since you wrote this post but I am just reading it today.
According to a recent review I did when a similar question cam up, IVC filters have never really shown to reduce PEs, let alone DVTs. We do them because we feel like we should do something. And they are better than nothing when one has an acute bleed or cannot is at high risk of bleeding.