Angiovac System Removes Large High-Risk Clots in Vasculature

Alice Goodman

November 29, 2011

November 29, 2011 (New York, New York) — The Angiovac endovascular clot removal system (Vortex Inc.) appears to be safe and effective for the treatment of massive pulmonary emboli and removal of large clot burdens, according to worldwide experience with the first 105 patients treated with this device. Study of the system is still a work in progress, researchers announced here at the 2011 VEITH Symposium.

"What we've seen so far suggests that the Angiovac system is safe and effective for removal of acute clot (<3 months) and is a novel approach for inferior vena cava and iliac vein thrombosis, pulmonary emboli, and atrial thrombus, particularly in those with contraindications to thrombolysis," said principal investigator Christopher Kwolek, MD, a vascular surgeon at Harvard Medical School and director of endovascular training at Massachusetts General Hospital in Boston.

Pulmonary embolism (PE) and venous thromboembolism pose a huge burden to the healthcare system, with about 300,000 to 660,000 new cases per year in the United States. Even if the clot does not travel to the lung or heart and cause death, a large clot in the leg can cause chronic ulceration, post-thrombotic syndrome, and chronic venous insufficiency. Additionally, clots that remain in the vasculature can cause chronic pulmonary hypertension, Dr. Kwolek explained.

Some clots can be treated with thrombolytic agents, such as tissue plasminogen activator, but this treatment works slowly over several days. "Patients with a large clot burden who have trouble breathing may need emergency surgery, which is risky. Angiovac is an alternative to surgery. The company that developed the Angiovac system [Vortex] was started by a cardiothoracic surgeon whose main job was treating pulmonary emboli and he felt that there was a better way than existing treatments," Dr. Kwolek said.

The Angiovac system is a large-bore device designed to remove undesirable intravascular material, such as clots, tumors, or any type of foreign material in the vascular system. The system can be introduced via the groin or neck. Unlike smaller catheters, such as the Angiojet, the Angiovac system has a fairly large bore (about 22 French). It was designed to remove the entire clot burden intact.

Over the past 2 years, 105 patients worldwide have been treated with this device. Approximately 20% of these patients were treated at Massachusetts General Hospital. The clot was located in the pulmonary artery in 21% of cases, the right atrium in 26%, and the inferior vena cava or iliac vein in 53%. One of the first 31 patients died of right atrium perforation, but since then there have been no other deaths. Clot or mass removal was successful in 90% of patients. Patients received blood thinners after the procedure.

"Experience suggests that the Angiovac system works best in clots that are only about 3 months old. I used it predominantly in the inferior vena cava and iliac veins in the lower half of the body. At our institution, cardiologists use it in the upper half. It was originally designed to treat veins," Dr. Kwolek explained.

A subset of 7 patients included in the group of 105 patients who were treated with the Angiovac system had contraindications for thrombolysis, including phlegmasia (massive clots in the lower extremity), a significant bleeding history, and a history of failed thrombolysis. "That means it was either lose their leg or their life," he commented. No major amputations were required. One patient had to have some toes amputated. The 30-day mortality rate was zero.

Dr. Kwolek said the baseline characteristics and other data on the 105 patients have not yet been analyzed, but there is a mix of ages. One patient was as young as 18 years.

"Angiovac represents a true advance because of the ability to remove large amounts of thrombus in a rapid fashion without clot-busting medicine. The system has the potential to revolutionize the way we manage massive thrombosis in the venous system, everywhere from the inferior vena cava to the right atrium to the pulmonary artery," Dr. Kwolek stated.

Iris Baumgartner, MD, head of interventional and clinical vascular medicine at the University Hospital, Bern, Switzerland, commented on the Angiovac system.

"We don't use Angiovac, but I'm well aware of this effective aspiration device. I think its role will be as a niche product for massive thromboembolism in the lung and vena cava and maybe for clotted caval filters," she said.

"The disadvantage is that its use is dependent on having a facility that performs heart and thoracic surgery and is equipped with cell saver. If you have fully equipped facilities and surgeons, I don't think it is dangerous, but its use will be limited to large-sized centers," Dr. Baumgartner said.

Dr. Kopek receives consultant fees from Vortex. Dr. Baumgartner has disclosed no relevant financial relationships.

The VEITH Symposium. Presented November 17, 2011.

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