Six-month outcomes of the ClotTriever Outcomes (CLOUT) Registry show promising results in patients undergoing mechanical thrombectomy for deep vein thrombosis (DVT), according to researchers.
The registry consists of 500 patients—currently the largest DVT cohort treated with mechanical thrombectomy—and examines the effectiveness of the ClotTriever System in treating DVT, according to the authors of Featured Abstract “Safety and Effectiveness of the ClotTriever System for Treating Deep Vein Thrombosis: Six-Month Outcomes of the Fully Enrolled CLOUT Registry,” which will be presented during Sunday’s Scientific Session 2, Deep Venous and Venous Access, Room 221C of the Phoenix Convention Center.
“The CLOUT Registry provides a robust and contemporary study population to evaluate both the immediate and long-term safety and effectiveness of this treatment option,” said presenter Abdullah Shaikh, MD, an interventional radiologist at the Allegheny Health Network. “The purpose of the research presented in this abstract is to evaluate the 6-month clinical outcomes—such as the development of post-thrombotic syndrome (PTS), which includes pain, swelling and reduced quality of life—in patients treated with the ClotTriever System.”
Because some patients are unable to receive treatment using thrombolytics, and complications like PTS continue to occur in patients with DVT, effective treatment options without the use of thrombolytics are needed, Dr. Shaikh says. He adds that the CLOUT Registry’s 6-month outcomes indicate that mechanical thrombectomy is a potential solution.
“In spite of treatment advances for DVT, many patients continue to develop PTS, leaving the patient with long-term disability and reduced quality of life. Furthermore, a proportion of patients are contraindicated to thrombolytic treatment due to its inherent bleeding risk,” he said. “Mechanical thrombectomy potentially provides both the desired effectiveness and good safety outcomes with less bleeding risk, but longer-term data are needed to better understand its full impact on long-term outcomes.”
Of the 499 patients treated with the ClotTriever System, 24.9% had experienced prior DVT and 29.7% were contraindicated to thrombolytics. Researchers defined the primary effectiveness endpoint as complete or near-complete (75% or higher) thrombus removal, which was measured by an independent core laboratory. An independent medical monitor determined serious adverse events.
Almost all patients (99.4%) were treated in a single session. The median thrombectomy time was 26 minutes and median blood loss was 40 mL. Few patients (2.2%) required an ICU stay post-procedure, and at 30 days, 8.4% of patients had experienced a serious adverse event, while 4.2% had been readmitted.
Six months after the procedure, patients were assessed for flow and compressibility, revised venous clinical severity, PTS (using Villata scores), pain and EuroQol group 5-D scores. Near complete thrombus removal was seen in 91.2% of limbs, and complete thrombus removal was seen in 63.8%.
“These findings demonstrate an excellent safety profile confirming previously described acute safety, as well as significant improvement in clinical parameters,” Dr. Shaikh said. “Importantly, only 8.6% of ClotTriever-treated patients reported moderate to severe PTS at 6 months, and greater than 90% reported an improvement in PTS severity (Villalta score) at 6 months.”
Over the next 2 years, the researchers will be following up with the registry cohort.
“We will continue to assess the long-term outcomes discussed in this presentation, including the presence of flow, compressibility and patency of treated veins, the incidence of post-thrombotic syndrome, and clinical scores measuring venous clinical severity, pain and quality of life,” Dr. Shaikh said.