strokes and holes in the heart

Monday, February 10, 2014

Trying to sort out medical conditions from press releases can be more than a little frustrating. A quote here, a headline there and perhaps the anatomy, physiology and injury can be understood. But unless the concrete details are leaked, most commentary is based on supposition. It was easy sorting out John Fox’s, the Denver Bronco head coach’s heart issue. He was playing a round of golf, passed out and was diagnosed with aortic stenosis, a narrowing of the heart valve that decreased blow flow to his body including his brain. Surgery was needed to replace the valve and recovery went well. The story flowed well and made sense. Such is not the case with Kris Letang, the Pittsburgh defenseman, whose medical issues are a little more confusing.

According to quotes from the team general manager, Mr. Letang complained of dizziness and nausea. Tests revealed that he had suffered a stroke, perhaps due to a congenital heart issue. Further tests were scheduled and treatment included prescription blood thinners. His playing status was uncertain but he was ruled out of the lineup for at least 6 weeks. That’s it, that’s all there was. The clues suggest a best guess that Mr. Letang suffered a cerebellar stroke due blood clots arising from a patent foramen ovale. Young people, especially elite athletes, aren’t supposed to have strokes. It should be a disease of old people and yet they happen.

Strokes are most often caused by atherosclerosis or narrowing of the arteries within the brain that can gradually develop over years. Risk factors include high blood pressure, high cholesterol, diabetes and smoking, take time to cause the narrowing and it makes sense that they are also related to being older and perhaps not paying attention to one’s body. Strokes may also be caused by atrial fibrillation where an irregular heart rhythm allows blood clots to form in the upper chamber of the heart, break away and clog an artery in the brain. Strokes in young people are not common and when they occur, the search begins for causes that aren’t related to older age. That search often begins with the heart, looking for structural changes that could allow blood clots to form and then break off to travel to the heart. One of the usual suspects is a patent foramen ovale (PFO).

Aside from neonatal surgeons who sometimes operate on a baby in the uterus, most doctors have no interest in embryology, the study of fetus development. It’s a course that they suffer through in first year medical school as a rite of passage. But having some knowledge about how a fetus grows into a baby is sometimes helpful. In the uterus, the fetus gets it oxygen through the umbilical cord from the mother. There is no need pump blood to the lungs until after birth and for that reason, blood flow in a fetus is different than once it has emerged into the real world. Mother’s blood filled with oxygen is pumped by the fetal heart throughout the body but it is shunted away from the fetal lung. The foramen ovale, a hole in the atrial septum that separates the right and left atrium, and the ductus arteriosus, a temporary blood vessel between the aorta and pulmonary artery, bypass the lungs. When the baby is born and takes its first breath, both these bypasses begin to close. The ductus closes within 24 hours while the foramen ovale may take a few weeks.

 

A PFO may be a normal variant and is often found incidentally in asymptomatic patients whether they are young, middle aged or old. Some doctors suggest that patent foramen ovale is associated with strokes and complicated migraine headaches. Surgery is not usually recommended to repair the hole in the atrial septum. Sometimes medications to “thin” the blood is recommended. However, a philosophic issue exists. Research is mixed as to whether a PFO may contribute to stroke. As well, the use of anti-coagulation medication whether it be aspirin, warfarin (Coumadin) or other newer anti-coagulation drugs have not been conclusively proven to work in stroke prevention.

And there lies the rub. Young people aren’t supposed to have strokes. Doctors and their patients want to make a diagnosis that can lead to a treatment that will prevent the next stroke. The question yet to be completely answered is whether a stroke patient with a PFO needs anything done but medical knowledge may be lacking..

If Mr. Letang were to be treated with aspirin and recover from his stroke symptoms, then his hockey career would likely continue. If the decision is made to prescribed Coumadin or another more aggressive blood thinners, his playing days are done. Increased bleeding tendencies and body checks are not compatible. Patients who are anti-coagulated are more likely to bleed, even with the most minor of bumps or falls.  At the end of the day, medicine is all about risk reward. What are the risks of bleeding when blood thinners are prescribed to treat a PFO? What are the risks of playing hockey with a PFO that is not treated?

And a reminder: this is all supposition based on a headline and a quote. It is wise to question those who practice medicine by proxy.

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