Every morning when I pull into the parking lot at 27 Point Finger Road, I go through a little ritual. I turn off the radio, roll up the windows, and switch off the ignition. Then I check my look in the rear-view mirror. Not to see if my hair is tame, but to see if I’m bleeding. That’s because a few minutes earlier I shaved, and I don’t want to breeze past my office manager, Liseta, with blood trickling down my lip. Let’s face it, when something’s bleeding we want a clot and we want it now. But as it turns out, human survival depends on a delicate balance between bleeding and clotting.
Let me explain. Our circulation is composed of miles of arteries, veins, and capillaries. I’ve been told that if you lay all those blood vessels out in a straight line, they would stretch out about 60,000 miles, or put another way, one person’s blood vessels could wrap all the way around earth 2.5 times. So, with miles of vessels packed into one body, you can imagine what a job it is to keep them intact, especially when we keep running into things that damage them. When a vessel is injured, the brain sends platelets – the sticky components of blood – to the site of bleeding and these, together with coagulation factors, form a clot and stop the bleeding. Ingenious! So whether a vessel is punctured by a thorn in the garden, a carelessly-wielded disposable razor, or a knife in a dark alley, the ability to form a blood clot is life-saving.
But there are other threats to blood vessels beyond sharp objects. Sometimes things in our kidneys or bladder (stones, tumors, inflammation) can cause bleeding. Anyone who’s gotten up in the middle of the night to urinate and sees red stuff come out knows how alarming internal bleeding can be. Or sometimes a stomach ulcer or an intestinal diverticulum can start bleeding, turning your bowel movement into a crimson mess or – if the blood is first digested – into sticky black goo. Equally off-putting. Thank goodness blood knows how to clot and stop bleeding when necessary.
Unfortunately, there’s another property of blood which isn’t helpful at all. Even if there’s no injury to a blood vessel to initiate a clot, as soon as blood stops moving it congeals – this is true whether in an artery, a vein, or even inside your heart. I’m sure you’ve heard advice that when you take a long airplane ride you should drink plenty of water, stretch your legs, and pace the aisle a few times. This helps prevent blood from stagnating in your leg veins and forming a clot. If a clot develops during a plane ride, you usually know about it because your leg swells and it hurts. More dangerous still, is if that clot dislodges and travels to the lungs where it can make you very short of breath, or worse.
Another common situation in which blood slows within the circulation is atrial fibrillation. Atrial fibrillation is an irregular heart beat in which the top chambers – the atria – quiver or fibrillate, and the bottom chambers – ventricles – try to keep up by beating rapidly and irregularly. When the atria fibrillate, blood swirls, slows, and can clot inside the heart. The trouble with fibrillation is that you don’t know if a heart clot has formed until it dislodges. Once free, that clot can travel anywhere. If it heads north to the brain, that’s a stroke. So we use blood thinners – Warfarin, Pradaxa, Xarelto, Eliquis, Edoxaban – to prevent clots from forming in the hearts of patients with fibrillation.
Now here’s a conundrum for you: what happens if you’re clotting and bleeding at the same time? What if you had a stroke from atrial fibrillation, your doctor put you on blood thinners, then you start hemorrhaging from your stomach or bowels, passing so much blood that you need transfusions? Unfortunately, it’s a more common scenario than you think. Your doctor doesn’t want to keep you on a blood thinner that’s aggravating bleeding and they don’t want to take you off it in case you have another stroke. What now?
One option is a little jelly-fish shaped device called the Watchman. The Watchman seals the exit from the left atrial appendage (the part of the heart where most atrial fibrillation-related clots form) thereby preventing them from entering the circulation. It’s inserted via a groin artery under general anesthesia and typically takes less than an hour. It’s made by Boston Scientific and they have a nice video to watch that explains how it works. Plug this link into your browser to learn more, here.
The Watchman Device Won’t Let Clots Leave the HeartAnd if a jelly-fish-shaped device doesn’t appeal to you, just last month a new filter was introduced by Javelin Medical – this one placed in the carotid arteries to prevent blood clots from reaching the brain. It’s like a little coiled passion fruit vine, but it’s made of a super-elastic wire, and it’s inserted using local anesthetic by puncturing the carotid artery (in the neck) with a needle. A tiny motorized machine injects the Vine into the artery where it lodges, unfurls, and acts as a filter. There’s a 1-minute video on the Javelin website that shows you how it works: https://www.javelinmed.com/about-vine
The Vine catches clots before they reach the brain: Because there’s a left and right carotid artery going to the brain, you have to have the Vine inserted in both sides of your neck. So far, 25 patients have been tested with the Vine devices, and after 6 months, all patients were doing well – there were no major complications from the devices, and ultrasound scanning demonstrated that the filters trapped clots in 4 patients before they could land in the brain and cause a stroke. So it seems this new method of catching clots is technically feasible and safe: Translation – yes, it can be done. Further studies need to be done before it’s routinely available, but what a smart idea.
Final Thoughts on Catching Blood Clots…
A stroke, whether from atrial fibrillation or any other cause, can be devastating and sometimes fatal. So my immediate reaction when a doctor identifies someone with atrial fibrillation who hasn’t yet had a stroke is – lucky you: we have lots of choices and lots of experience with blood thinners that can prevent clots from forming. As for the contraptions to keep clots from reaching the circulation or catching them once they’re released, I know what you’re thinking – I don’t want a jellyfish plug in my heart and I don’t want metal Vine coils in my neck. Neither do I, really. But when so much disability can arise from a blood clot travelling where it doesn’t belong, you have to agree – it’s wonderful to have options for those with atrial fibrillation who are unable to take blood thinners. So, let’s dissolve those clots, and if we can’t dissolve them, let’s catch them!
For more news on the latest developments in cardiology, visit www.ShaneMarshallMD.com, subscribe to the free newsletter The Annals of Cardiology, and follow Dr. Marshall on Twitter @ShaneMarshallMD.
