Blood Clot Blues: Why Does This Keep Happening?

For someone who keeps a keen eye on goings-on in hockey, it certainly caught my attention. Tomas Fleischmann, Tomas Vokoun, Paul Postma, Kimmo Timonen... It seemed like every couple of months another hockey player was dealing with blood clot issues.

It wasn't until November 2014 that this nagging little question in the back of my head really hit home. The Penguins announced the dreaded 1 pm press conference. Another blood clot, this time to my favorite player, Pascal Dupuis. Six months on oral anticoagulants, then we'll see, they said.

Duper has been out for a few months now, and has written a heartfelt piece in The Players' Tribune talking about his experience. Stephen Whyno of the Canadian Press has written a thorough and well-researched article on the almost-epidemic of hockey players with blood clot issues.

Is there anything that perhaps makes these guys more susceptible to blood clots? It's not necessarily something that you would expect to happen a lot in this population. In my mind I always associated it with a sedentary lifestyle, 12 hours on the plane, that sort of thing. Digging through medical journals, I was surprised to find so many case reports involving athletes. Once I was through reading all these papers, it made a lot more sense to me.

Deep vein thrombosis (DVT) is the formation of a blood clot in a deep vein, usually in a calf or thigh muscle. It can partly or completely block blood flow, causing chronic pain and swelling (Vokoun's leg circumference was 4 inches bigger on the left than on the right due to all the swelling). It can also damage valves in blood vessels, making it difficult to get around. Worst of all, a blood clot can break free and make its way via the blood stream to any number of major organs, such as heart or lungs. Once there, it can cause death within hours by blocking blood flow and thus depriving tissues of oxygen. Untreated DVT will result in a pulmonary embolism 50% of the time.

Like most diseases, there are two kinds of risks that can play a role: hereditary (genetic) risk factors and acquired (lifestyle) risk factors. Hereditary risk factors include factor V Leiden and prothrombin G20210A mutation, and deficiencies of antithrombin III, protein C, and protein S. Acquired risk factors include trauma, immobilization, surgical procedures, high altitude, long-distance travel.

If you read through the list of acquired risk factors, they all fit the general job description of a hockey player. Trauma (blocked shots): check. Surgical procedures: check. Immobilization: check. Pascal Dupuis, for example, suffered a major knee injury in late December 2013 in a game in Ottawa. Flying back to Pittsburgh his knee was immobilized, which led to initial clot formation in his affected leg. In the 2008 playoffs, Kimmo Timonen blocked a shot by Montreal defenseman Andrei Markov, leading to a blood clot in his left ankle.

The American Academy of Orthopaedic Surgeons recommended in this excellent 2013 article that orthopaedic surgeons screen athletes for thrombogenic risk factors, including history of venous thrombosis, hypercoagulable disorders, or high altitude exercise, during preparticipation physicals and preoperative evaluations. That will go a long way toward identifying those at higher risk. Obviously a person's own recognizance is very important here as well.

While my heart hurts for Dupuis, who is the favorite hockey player for three generations of Penguins fans in my family, he needs to be smart and prudent about it. All of the madman training he did to come back in October was quickly offset by playing through another episode of clotting and being silent about it. If managed properly, he can come back and keep playing. Tomas Fleischmann keeps blood clots at bay and continues to play 4 years after his initial diagnosis. Kimmo Timonen is set to return tomorrow night against the Rangers. He can do it too. Whether this spring or this fall, I hope Super Duper is back on the ice, where he belongs. We'll all be there watching and cheering.