Endovascular therapy for deep vein thrombosis (DVT), typically combining lytic and mechanical clot removal, shows promising periprocedural safety and efficacy, according to combined data from 2 prospective registries presented January 21, 2013, at the International Symposium on Endovascular Therapy (ISET) in Miami Beach, FL.

Researchers led by Robert A. Lookstein, MD, of Mount Sinai Medical Center (New York, NY), looked at 371 symptomatic patients with 1,346 thrombotic vessels who underwent endovascular therapy with the AngioJet thrombectomy device (Medrad, Warrendale, PA) at 35 centers. More than two-thirds of patients, who were enrolled in the PEARL I and II registries, reported symptom onset within the past 14 days and almost half within 7 days.

So-called combination therapy was used in 86% of cases. In this pharmacomechanical approach, the catheter is positioned in the thrombus and a thrombolytic agent is delivered through the tip to soften the clot. Then, pressurized saline jets create a vacuum that draws the clot into the catheter, where it is fragmented and aspirated. In about 60% of cases, additional catheter-directed lysis was used.

Procedure Safe, Efficient

Overall, 38% of cases were completed within 6 hours and 76% within 24 hours, with 87% of patients requiring no more than 2 sessions. Substantial or complete lysis was achieved in 95% of treated vessels. Adjunctive stents were implanted in 32% of patients.

In preliminary clinical follow-up from PEARL II, quality of life, as measured by the SF-12 Health Survey, improved from baseline in both physical and mental components (table 1).

Table 1. SF-12 Quality of Life Scores^a

^a P < 0.0001 for all time points vs. baseline for both components.

In addition, estimated rates of freedom from rethrombosis for the entire cohort were 94% (95% CI 91-96) at 3 months, 86% (95% CI 81-90) at 6 months, and 81% (95% CI 73-87) at 12 months.

According to Dr. Lookstein, these voluntary registries capture the ‘real-world’ experience of a variety of specialists with busy DVT practices in North America. Still, the procedure is currently performed in only 1% to 2% of DVT patients, he estimated.

Bleeding complications are the most feared risk of any treatment that involves a thrombolytic agent, Dr. Lookstein noted, and in this cohort those events were “very rare and in line with historic data.”

Bleeding requiring transfusion was seen in 8 patients (2.2%), hematoma in 5 (1.3%), transient renal failure in 2 (0.5%), and hyperbilirubinemia and pulmonary embolism in 1 (0.3%) each. The low rate of pulmonary embolism was observed despite use of a vena cava filter in only a quarter of patients, Dr. Lookstein reported.

A Paradigm Shift?

A barrier to wider use of endovascular therapy has been the reluctance of many doctors to admit patients to the hospital to undergo an invasive procedure for a problem that is perceived to be relatively benign and can be managed with outpatient anticoagulation, Dr. Lookstein observed. “But now we’ve identified a technique and a technology that has the prospect of transforming the treatment of symptomatic DVT into an ambulatory [procedure] in a significant percentage of patients,” he said. “This is a dramatic paradigm shift as compared to historic studies where patients were treated on average for 48 hours or longer.”

Given the registry results, “we’re hopeful that endovascular treatment will be offered to a broader spectrum of the population,” Dr. Lookstein concluded.

In a telephone interview, Mahmood K. Razavi, MD, of St. Joseph Hospital Heart and Vascular Center (Irvine, CA), told TCTMD that the study adds to the body of evidence supporting interventional management of DVT patients. “It confirms the safety of this new approach,” he said, and shows the potential for reducing the duration of therapy. However, the number of patients who were treated in less than 6 hours was relatively small, Dr. Razavi observed.

More Clinical Data Awaited

Most important, the study falls short in terms of information on clinical outcome, Dr. Razavi commented. For example, the incidence of post-thrombotic syndrome, a key endpoint that affects up to half of patients receiving standard therapy, is unreported, he noted.

According to Dr. Lookstein, however, the QOL metric was viewed as a surrogate for post-thrombotic syndrome. And thus far, “patients who had acute procedural success have had dramatic improvements in their quality of life,” he added.

Dr. Razavi called the slow but steady decline in freedom from rethrombosis over 12 months “curious” because in previous studies most failures occurred within the first month.

The absence of a core lab and independent adjudication of endpoints weaken the study’s impact, Dr. Razavi said, as does the lack of a comparator. Convincing evidence that interventional management is better than standard treatment must await results of randomized trials such as ATTRACT and rigorous comparisons with historical controls, he added.

Nonetheless, he concluded, “as a very preliminary study, this looks encouraging.”

Study Details

Mean patient age was 51.9 years and 58% were men. Of the overall cohort, 35% had a previous DVT, 38% were current or past smokers, and 24% had a preexisting vena cava filter.

The great majority (89%) of thrombi were located in a lower extremity. Treated segments included iliac femoral popliteal (31%), iliac femoral (27%), femoral popliteal (24%), iliac only (7%), femoral only (6%), and popliteal only (2%).

For all lytic patients, the mean total dose of alteplase was 13.4 mg, while for those who received Angiojet and catheter-directed lysis the mean total dose was 25.9 mg.

Related Stories:

• Catheter-Directed Thrombolysis Beneficial for Proximal DVT
• Catheter-Based Device Can Bust DVT Clots Safely and Effectively
• Direct Lytic Injection Shows Promise in Severe DVT