By Marti Webb Slay
Interventional cardiologist Mark Sasse, MD wants to increase awareness about current treatments for deep vein thrombosis (DVT) and prevention of post thrombotic syndrome. “When I was a cardiology fellow, we didn’t have the equipment, the knowledge or the desire to treat DVTs more aggressively,” he said. “DVTs can be neglected, because they are typically treated with only anticoagulant therapy. Physicians would prescribe anticoagulants, and we thought we did our job. Unfortunately, a significant minority of patients, approximately 20 to 50 percent, develop post-thrombotic syndrome, a chronic disease that occurs after a large unresolved thrombus, even with optimal anticoagulant therapy.
“The symptoms of post thrombotic syndrome can include leg swelling, leg pain, color changes below the knee, venous ulcers and ultimately, disability. The sequelae of post thrombotic syndrome are difficult to treat.”
Thrombolytic therapy, one of the modalities to treat large DVT, can increase the risk of bleeding. It may not resolve the thrombus completely since some of the thrombus is chronic. There are also options to use balloon angioplasty to disrupt the chronic thrombus. However, this does not usually result in a durable long-term outcome. Aspiration devices have been available for several years but are limited in their ability to extract chronic thrombus.
Compression stockings are another common treatment for DVT. “They improve symptoms, but numerous trials show they don’t change the long-term outcomes for post-thrombotic syndrome,” Sasse said. “They don’t change the pathophysiology because the thrombus is still present.”
The Inari company has now developed the ClotTriever catheter that removes the clot and restores blood flow in the affected vein. “This device has a soft blade at the end of a windsock-like basket, which catches the clot, preventing it from embolizing. We can pull the clot from the vein, out of the body and restore complete blood flow,” Sasse said. “Grandview Medical Center was a participant in the original CLOUT trial proving that patients have reduced risk of developing post-thrombotic syndrome with intervention.
“The procedure can be performed as an inpatient or as an outpatient. We can access the patient from multiple points. From the internal jugular vein access, clots in the inferior vena cava, which resides in the abdominal cavity, can be extracted. In other cases, we place patients in the prone position in the catheterization laboratory and then access the popliteal vein. We put a sheath in the vein and place wire through the DVT. Then we upsize the small sheath to a much larger sheath so the ClotTriever can be delivered to the affected vein and extract the thrombus.
“It takes a high level of expertise to do the procedure in order to keep the bleeding risk low. Since the venous system is low pressure, we can obtain hemostasis relatively easily and mobilize the patient quickly. Typically, we use the ClotTriever first to extract the thrombus. We can make multiple passes, and if we are happy with the result, we conclude the procedure. If there is residual thrombus, we can use adjunct devices such as balloon angioplasty and aspiration catheters to help extract the rest of the thrombus.”
“If the procedure is outpatient, the patient recovers for three to four hours, and then they are sent home, if there is no bleeding. They resume their anticoagulants immediately. Patients usually achieve resolution of the thrombus in three to six months, but it can take up to year. Residual thrombus after anticoagulation is a risk for reoccurrence of DVT.”
Symptoms of a DVT can be as simple as heaviness or tiredness or just an odd feeling in the legs. Other symptoms are itching or cramps, varicose veins, and redness. “If you are not a pigmented person, you can see legs turn a copper color below the knee. In darker skinned patients, the skin will get darker and more indurated,” Sasse said. “If a physician suspects DVT, a venous ultrasound is the most expeditious diagnostic test. It’s easy, safe, and widely available.”
Sasse encourages physicians to consider the possibility of a DVT earlier so intervention can be performed before the onset of post thrombotic syndrome. “Cardiology fellowship trained us to be heart and artery doctors,” he said. “We ignored the venous system. When cardiologists observe swelling, edema or leg pain, we think it is a cardiac condition or related to peripheral arterial disease. Patients and physicians can diminish the symptoms of venous disease because it doesn’t appear to be an urgent problem."
Sasse cautions against clinical inertia, or the idea that physicians treat DVTs the way they always have. “Even if we can’t extract all the thrombus, enhanced flow in the vein leads to better patient outcomes,” he said.
Ultimately, extracting a blood clot can result in improved quality of life. “Many patients are miserable from post thrombotic syndrome,” Sasse said. “Given our expertise, we can make people asymptomatic after this intervention.”
