Dr. Christopher Kwolek: Pioneering New Blood Clot Treatments
January 24, 2013
Written and Produced by Michelle Alford for Medtech1
Christopher Kwolek, M.D., is a vascular/endovascular surgeon at Massachusetts General Hospital and directs the clinical training program that trains future vascular/endovascular specialists. He is pioneering a revolutionary treatment for severe blood clots.
Why don’t you tell me a little bit about yourself?
My name’s Christopher Kwolek and I am a vascular/endovascular surgeon at the Massachusetts General Hospital in Boston, Massachusetts. I take care of patients there. I’m also the director of the clinical training program for training the next generation of vascular/endovascular specialists within the Mass General Hospital for the department of surgery. My practice involves treating all types of patients with problems related to circulation. That could involve everything from aneurisms in the chests or the abdomen to blockages in arteries essentially anywhere in the body, excluding problems inside the brain and problems inside the heart. We also more recently have become very involved not only with treating problems with blockages from the arteries, which carry the blood away from the heart, but also some of the major blood vessels that carry the blood from the legs and extremities back to the heart and the chest. The topic of my recent talk was related to a new technique for managing patients with very large blood clots that are either in the major vein coming from the legs or in the abdomen going up to the heart and the lungs.
Can you tell us a little more about your talk?
One of the areas, at least in the U.S., that’s been very much underappreciated is the problem related to blood clots occurring in patients who have been traveling long distance or have had a recent surgery or trauma. When these clots occur they cause an obstruction or a blockage. Think of it like a damn or stream. When the blood vessel blocks up, the pressure behind it builds. If, for example, there’s a problem with a blockage in a vein in the leg, there’s a decrease in the amount of blood that returns back to the heart and the lungs, but, just as importantly, that blockage causes a lot of swelling and edema in the leg. Now that can be dangerous in several ways. One, if a piece of that clot were to travel or to break off, that could actually go directly to the heart and into the lungs, to the pulmonary arteries, and that often could be either severely debilitating or even life threatening. That was really the topic of this talk. However, in addition, if the clot stays in the leg or stays in the veins in the abdomen or the pelvis, it can also over the course of weeks, months, even years, cause secondary congestion, problems with pain, problems with swelling, and, more importantly, long-term disability in terms of things like ulcers, sores, and non-healing wounds down in the lower extremity. It’s a little bit different than what we often think of when we think of circulation problems. At least in my current practice, many of our patients have problems with the blood getting into the leg and the arteries, but this is actually a problem with the blood flowing back out of the legs.
About two years ago, we became aware of a new device—a new technique to be able to go in and actually remove very large segments of clot with this new mechanical thrombectomy tool. I think the easiest way to think of it is it’s actually like a suction tubing or a vacuum hose. It’s hooked up to a partial bypass pump where we introduce this into the abdomen, pelvis, or leg, and we’re actually able to remove very large areas of clot. Prior to this, the ways that we would use it would be either going in with a catheter and trying to break it up, or using what’s referred to as clot-busting medicine—often TPA. That can work, but it obviously takes a little bit longer, and the concern is some of these clots are very, very large and when you’re breaking them up, they could travel elsewhere, for example up to the heart and the lungs. This is a new technology that’s become available. Initially it was designed by a heart surgeon up at Brigham’s and Women’s Hospital to retrieve clots out of the pulmonary artery, which is the major artery going into the lungs. But I was actually a conference, sort of a heart and vascular conference, saw this, and after talking with the inventors, it became clear that there were other applications, not just for the heart, but also for use in the peripheral veins and in the inferior vena cava, which is the main vein that brings blood from the legs back to the heart and into the chest.
How do you think treatments are going to continue to change in the next five to ten years?
One of the biggest things that we can do is increase patient awareness. And not just patient but also physician awareness, because I think many times patients come in with these large clots in the abdomen or the pelvis, or have even had clots that have traveled to the heart and the lungs, that are undiagnosed, unrecognized, or potentially even undertreated. I think for many years the standard way of treating this was with heparin, a blood thinner. This is a good first start, but in many patients, particularly ones who are relatively healthy otherwise and are able to undergo what certainly is a more aggressive or invasive procedure, the potential benefit of our new treatment is that five years, ten years, fifteen years down the road, they have a much better quality of life and functional status. Whether it’s less swelling, pain, and discomfort from the legs, or whether it’s better heart and lung function and capacity, we get there by aggressively trying to remove clots that are sitting in the heart or the arteries going out to the lungs.
What do you think is most important for patients to know about this?
I think it’s important for patients and their families to understand that when they have something that’s unexplained, such as a sudden change in the size of one leg, particularly if they’ve been on a recent trip or had a recent hospitalization, that they should seek further attention to evaluate whether or not there’s something going on in terms of an acute blood clot. It doesn’t just have to be in the hospitalized patient. I’ve had patients who have recently undergone what would be relatively minor surgery, are off a long plane flight from overseas, or have taken a recent car ride and have had problems with fairly sudden onset of pain, swelling, discomfort, and a clot. Eventually they need to make it to either the physician’s office or an emergency room and get seen.
The other thing is to ask questions. It’s always good to ask questions like, “What are my options for treatment?” “I understand I can be treated with blood thinners, but are there other options, such as clot busting medications or catheters, that might be able to remove the clot more rapidly?” And then, like with any intervention, I think it’s always very important to understand and to ask about the potential risks and the benefits. Because obviously as we think about a more invasive procedure or a more aggressive procedure, it certainly has potential benefits in terms of removing clot, opening up circulation, or restoring flow through a certain area, but there’s also, inherent with that, some amount of increased risk if you’re performing a more invasive or aggressive procedure.
Do you have any patient stories that you’d like to share?
I think that probably the best, most recent story is a patient of mine who otherwise was very, very active, healthy, walking on a regular basis, who had undergone what would have been considered a relatively minor scope procedure for the knee. After that, she developed some swelling on one side, ended up going on blood thinners, and found that she had developed a major clot going up the leg. She ended up coming back in and getting admitted to the hospital. The clot had progressed to the point where it was not only affecting the leg but was swelling all the way up to the hip and the pelvis, so much so that I was very concerned that it might be something that could potentially risk long-term ulcers, inflammations and sores, and could be very dangerous, certainly in terms of risk of traveling elsewhere. We went in and put in a temporary umbrella above the clot so that it wouldn’t travel, or if it did it would be captured and not go to the heart and the lungs, and then proceeded to go ahead and try to open that up or break that up. Initially we tried with smaller catheters and, because there was so much stenosis there, could not successfully do that. So with this newer vortex procedure, with this large vortex suction aspiration thrombectomy catheter, we actually went in through a small incision in the groin, opened up and removed the clot there, and then used this catheter system to remove the clot in the leg. At the same time we used this new ultrasound device to look inside the blood vessel and found that the vein from her left leg was being compressed by her own artery, which is called May-Thurner syndrome. We were able to identify that, treat it with a stint, and reestablish flow through there. So it wasn’t just one thing. It wasn’t just the surgery. She had recent surgery, so a period of relative immobilization. She had an anatomic compression that she’d had for her entire life. It was the combination of that and perhaps something about her blood at the time of surgery that made it a little bit thicker that made her prone to having the clot. The good thing is I just saw her back in the office very recently. Her leg has gotten back to normal and the swelling’s gone. More importantly, when we do the ultrasound to look at the veins in the leg, they’re functioning and working normally. The concern with many of these patients is once they have a blood clot in that vein and it stays, even if it partially recedes slowly over time with heparin, that can damage the inside of the vein and damage the valves. There’s actually a series of one-way valves in the veins so that as you walk and move around, the blood travels from the foot to the calf to the thigh, up into the abdomen and back to the heart. And those valves are what prevent the blood from backing up when you’re standing up and walking. They’re one way valves back to the heart. When those valves are damaged, then the blood can back up and become more congested down in the leg, and so it’s critically important to be able to open those veins back up, restore flow, allow that area to heal, and recover that valve function. From her viewpoint, the hope would be that ten years, fifteen years from now she’s active, ambulating, has good function in her veins, and she’s back to living a normal, active, healthy life.
Then we go in, and this is another very important point, as we see more patients with these clots in the legs and in the pelvis, we will often put this temporary umbrella or basket or ivc filter in above the clot to try to prevent it from breaking off and traveling to the heart. Once they’ve had that done, once the clot’s been removed and they’re a little further out from the procedure, we’ll actually be very aggressive about following those patients up and going back and taking that umbrella, or that basket, out. There has been a great deal of concern recently that if you leave the filters in for longer periods of time, there can be complications and problems with the filter itself, so there’s been a very big emphasis both regionally and nationally to aggressively follow these patients up to make sure that we’re going back and removing filters in everybody except for the patients who absolutely need to have something in long-term.
Is there any other advice that you have for patients?
I’ve been very impressed with the number of patients who come in with very good questions having researched and thought about problems. I realize it can be challenging sometimes because with the internet there’s so much information out there it’s often hard to differentiate. But I think it’s very good and reasonable for patients to be informed and then come in and have the opportunity to interact one-on-one with their physician, whether it be their primary care physician or if it’s an area that a specialist should be involved, I think that’s very helpful as well.
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