Mechanical thrombectomy using the ClotTriever device (Inari Medical) for iliofemoral deep vein thrombosis (DVT) was found to be “associated with significantly” lower Villalta scores and a lower incidence of post-thrombotic syndrome (PTS) out to 12 months compared with treatment using anticoagulation, a propensity score matching analysis of a large randomized controlled trial (RCT) and registry data showed.
The study findings, led by first author Steven Abramowitz, associate professor of surgery at Georgetown University School of Medicine and chair of the Department of Vascular Surgery at MedStar Washington Hospital Center in Washington, DC, USA, were published online in the Journal of Vascular Surgery-Venous and Lymphatic Disorders (JVS-VL).
To assemble a propensity matched cohort, Abramowitz et al plumbed ATTRACT, the largest trial in the venous space to assess pharmacomechanical catheter-directed thrombolysis (pCDT) compared to anticoagulation, and the single-arm CLOUT registry, which included patients receiving mechanical thrombectomy with the ClotTriever.
A total of 164 pairs were matched, with no significant differences in baseline characteristics after matching, the authors noted.
They found that there were fewer patients with any PTS at six months (19% vs. 46%; p<0.001) and 12 months (17% vs. 38%; p< 0.001) among patients receiving mechanical thrombectomy.
Abramowitz and colleagues discovered upon statistical modeling that, after adjusting for baseline Villalta scores, patients treated with anticoagulation had “significantly higher odds” of developing any PTS (odds ratio [OR] 3.1; 95% confidence interval [CI], 1.5–6.2; p=0.002), or moderate-to-severe PTS (OR 3.1; 95% CI, 1.1–8.4; p=0.027) at 12 months compared with those treated with mechanical thrombectomy. They further found that mean Villalta scores were lower through 12 months among those receiving mechanical thrombectomy versus anticoagulation (3.3 vs. 6.3 at 30 days; 2.5 vs. 5.5 at six months; and 2.6 vs. 4.9 at 12 months; p <0.001).
“Propensity score matching of patients in the ATTRACT and CLOUT studies showed that, despite more limited use of compression stockings, treatment with mechanical thrombectomy resulted in a significantly lower PTS incidence and improved Villalta scores compared with anticoagulation treatment,” the authors wrote. “Those treated with mechanical thrombectomy had 27% and 21% lower rates of PTS at six and 12 months, respectively, as well as significantly lower mean Villalta scores at 30 days, six months, and 12 months. Similarly, matched patients treated with anticoagulation were found to have 3.1 times the odds of developing PTS at 12 months in logistic regression modeling adjusting for baseline Villalta scores.”
The authors noted the inherent limitations of propensity score matched analyses like the one they conducted. “A comparison of different clinical studies using propensity score matching by its nature introduces the possibility of bias from factors that differ between studies that are either unknown or unable to be controlled for,” Abramowitz et al wrote.
They highlighted how a RCT comparing iliofemoral DVT treatment using contemporary mechanical thrombectomy or anticoagulation would address most of their study’s limitations.
“Results from currently enrolling clinical trials will further clarify the role of these therapies in the prevention of PTS following an acute DVT event,” the authors concluded.
