Six-Month Deep Vein Thrombosis Outcomes by Chronicity: Analysis of the Real-World ClotTriever Outcomes Registry.

PURPOSE: To analyze the first 250 patients from the prospective, multicenter, industry-sponsored ClotTriever Outcomes (CLOUT) registry, assessing the safety and effectiveness of mechanical thrombectomy for acute, subacute, and chronic deep vein thrombosis (DVT). MATERIALS AND METHODS: Real-world patients with lower extremity DVT were treated with the ClotTriever System (Inari Medical, Irvine, California). Adjuvant venoplasty, stent placement, or both were performed at the physician's discretion. Thrombus chronicity was determined by visual inspection of removed thrombus, categorizing patients into acute, subacute, and chronic subgroups. Serious adverse events (SAEs) were assessed through 30 days. Clinical and quality-of-life (QoL) outcomes are reported through 6 months. RESULTS: Thrombus chronicity was designated for 244 of the 250 patients (acute, 32.8%; subacute, 34.8%; chronic, 32.4%) encompassing 254 treated limbs. Complete or near-complete (≥75%) thrombus removal was achieved in 90.8%, 81.9%, and 83.8% of the limbs with acute, subacute, and chronic thrombus, respectively. No fibrinolytics were administered, and 243 (99.6%) procedures were single sessions. One (0.4%) patient in the subacute group experienced a device-related SAE, a fatal pulmonary embolism. On comparing baseline and 6-month data, improvements were demonstrated in median Villalta scores (acute, from 10 to 1; subacute, from 9 to 1; chronic, from 10 to 3; for all, P < .0001) and mean EuroQol group 5-dimension (EQ-5D) self-report questionnaire scores (acute, 0.58 to 0.89; subacute, 0.65 to 0.87; chronic, 0.58 to 0.88; for all, P < .0001). There were no significant differences in outcomes across the subgroups. CONCLUSIONS: Mechanical thrombectomy using the ClotTriever System with adjunctive venoplasty and stent placement is safe and similarly effective for acute, subacute, and chronic DVT.

Analysis of the Final DENALI Trial Data: A Prospective, Multicenter Study of the Denali Inferior Vena Cava Filter.

PURPOSE: To report the final 2-year data on the efficacy and safety of a nitinol retrievable inferior vena cava (IVC) filter for protection against pulmonary embolism (PE). MATERIALS AND METHODS: This was a prospective multicenter trial of 200 patients with temporary indications for caval filtration who underwent implantation of the Denali IVC filter. After filter placement, all patients were followed for 2 years after placement or 30 days after filter retrieval. The primary endpoints were technical success of filter implantation in the intended location and clinical success of filter placement and retrieval. Secondary endpoints were incidence of clinically symptomatic recurrent PE, new or propagating deep vein thrombosis (DVT), and filter-related complications including migration, fracture, penetration, and tilt. RESULTS: Filter placement was technically successful in 199 patients (99.5%). Filters were clinically successful in 190 patients (95%). The rate of PE was 3% (n = 6), with 5 patients having a small subsegmental PE and 1 having a lobar PE. New or worsening DVT was noted in 26 patients (13%). Filter retrieval was attempted 125 times in 124 patients and was technically successful in 121 patients (97.6%). The mean filter dwell time at retrieval was 200.8 days (range, 5-736 d). There were no instances of filter fracture, migration, or tilt greater than 15° at the time of filter retrieval or during follow-up. CONCLUSIONS: The Denali IVC filter exhibited high success rates for filter placement and retrieval while maintaining a low complication rate in this clinical trial.

The DENALI Trial: an interim analysis of a prospective, multicenter study of the Denali retrievable inferior vena cava filter.

PURPOSE: To assess safety and effectiveness of a nitinol retrievable inferior vena cava (IVC) filter in patients who require caval interruption to protect against pulmonary embolism (PE). MATERIALS AND METHODS: Two hundred patients with temporary indications for an IVC filter were enrolled in this prospective, multicenter clinical study. Patients undergoing filter implantation were to be followed for 2 years or for 30 days after filter retrieval. At the time of the present interim report, all 200 patients had been enrolled in the study, and 160 had undergone a retrieval attempt or been followed to 6 months with their filter in place. Primary study endpoints included technical and clinical success of filter placement and retrieval. Patients were also evaluated for recurrent PE, new or worsening deep vein thrombosis, and filter migration, fracture, penetration, and tilt. RESULTS: Clinical success of placement was achieved in 94.5% of patients (172 of 182), with a one-sided lower limit of the 95% confidence interval of 90.1%. Technical success rate of filter placement was 99.5%. Technical success rate of retrieval was 97.3%; 108 filters were retrieved in 111 attempts. In two cases, the filter apex could not be engaged with a snare, and one device was engaged but could not be removed. Filter retrievals occurred at a mean indwell time of 165 days (range, 5-632 d). There were no instances of filter fracture, migration, or tilt greater than 15° at the time of retrieval or 6-month follow-up. CONCLUSIONS: In this interim report, the nitinol retrievable IVC filter provided protection against pulmonary embolism, and the device could be retrieved with a low rate of complications.

Comparison of anticoagulation vs mechanical thrombectomy for the treatment of iliofemoral deep vein thrombosis.

OBJECTIVE: To compare the comparative effects of treatment with contemporary mechanical thrombectomy (MT) or anticoagulation (AC) on Villalta scores and post-thrombotic syndrome (PTS) incidence through 12 months in iliofemoral deep vein thrombosis (DVT). METHODS: Patients with DVT in the Acute Venous Thrombosis: Thrombus Removal with Adjunctive Catheter-Directed Thrombolysis (ATTRACT) randomized trial and the ClotTriever Outcomes (CLOUT) registry were included in this analysis. Both studies evaluated the effects of thrombus removal on the incidence of PTS. Patients with bilateral DVT, isolated femoral-popliteal DVT, symptom duration of >4 weeks, or incomplete case data for matching covariates were excluded. Propensity scores were used to match patients 1:1 who received AC (from ATTRACT) with those treated with mechanical thrombectomy (from CLOUT) using nearest neighbor matching on nine baseline covariates, including age, body mass index, leg treated, provoked DVT, prior venous thromboembolism, race, sex, Villalta score, and symptom duration. Clinical outcomes, including Villalta score and PTS, were assessed. Logistic regression was used to estimate the likelihood of developing PTS at 12 months. RESULTS: A total of 164 pairs were matched, with no significant differences in baseline characteristics after matching. There were fewer patients with any PTS at 6 months (19% vs 46%; P < .001) and 12 months (17% vs 38%; P < .001) in the MT treatment group. Modeling revealed that, after adjusting for baseline Villalta scores, patients treated with AC had significantly higher odds of developing any PTS (odds ratio, 3.1; 95% confidence interval, 1.5-6.2; P = .002) or moderate to severe PTS (odds ratio, 3.1; 95% confidence interval, 1.1-8.4; P = .027) at 12 months compared with those treated with MT. Mean Villalta scores were lower through 12 months among those receiving MT vs AC (3.3 vs 6.3 at 30 days, 2.5 vs 5.5 at 6 months, and 2.6 vs 4.9 at 12 months; P < .001 for all). CONCLUSIONS: MT treatment of iliofemoral DVT was associated with significantly lower Villalta scores and a lower incidence of PTS through 12 months compared with treatment using AC. Results from currently enrolling clinical trials will further clarify the role of these therapies in the prevention of PTS after an acute DVT event.

Interim outcomes of mechanical thrombectomy for deep vein thrombosis from the All-Comer CLOUT Registry.

OBJECTIVES: The multicenter, prospective, single arm CLOUT registry assesses the safety and effectiveness of the ClotTriever System (Inari Medical, Irvine, CA) for the treatment of acute and nonacute lower extremity deep vein thrombosis (DVT) in all-comer patients. Reported here are the outcomes of the first 250 patients. METHODS: All-comer patients with lower extremity DVT were enrolled, including those with bilateral DVT, those with previously failed DVT treatment, and regardless of symptom duration. The primary effectiveness end point is complete or near-complete (≥75%) thrombus removal determined by independent core laboratory-adjudicated Marder scores. Safety outcomes include serious adverse events through 30 days and clinical outcomes include post-thrombotic syndrome severity, symptoms, pain, and quality of life through 6 months. RESULTS: The median age was 62 years and 40% of patients had contraindications to thrombolytics. A range of thrombus chronicity (33% acute, 35% subacute, 32% chronic) was observed. No patients received thrombolytics and 99.6% were treated in a single session. The median thrombectomy time was 28 minutes. The primary effectiveness end point was achieved in 86% of limbs. Through 30 days, one device-related serious adverse event occurred. At 6 months, 24% of patients had post-thrombotic syndrome. Significant and sustained improvements were observed in all clinical outcomes, including the Revised Venous Clinical Severity Score, the numeric pain rating scale, and the EuroQol Group 5-Dimension Self-Report Questionnaire. CONCLUSIONS: The 6-month outcomes from the all-comer CLOUT registry with a range of thrombus chronicities demonstrate favorable effectiveness, safety, and sustained clinical improvements.

A Prospective, Single-Arm, Multicenter Trial of Ultrasound-Facilitated, Catheter-Directed, Low-Dose Fibrinolysis for Acute Massive and Submassive Pulmonary Embolism: The SEATTLE II Study.

OBJECTIVES: This study conducted a prospective, single-arm, multicenter trial to evaluate the safety and efficacy of ultrasound-facilitated, catheter-directed, low-dose fibrinolysis, using the EkoSonic Endovascular System (EKOS, Bothell, Washington). BACKGROUND: Systemic fibrinolysis for acute pulmonary embolism (PE) reduces cardiovascular collapse but causes hemorrhagic stroke at a rate exceeding 2%. METHODS: Eligible patients had a proximal PE and a right ventricular (RV)-to-left ventricular (LV) diameter ratio ≥0.9 on chest computed tomography (CT). We included 150 patients with acute massive (n = 31) or submassive (n = 119) PE. We used 24 mg of tissue-plasminogen activator (t-PA) administered either as 1 mg/h for 24 h with a unilateral catheter or 1 mg/h/catheter for 12 h with bilateral catheters. The primary safety outcome was major bleeding within 72 h of procedure initiation. The primary efficacy outcome was the change in the chest CT-measured RV/LV diameter ratio within 48 h of procedure initiation. RESULTS: Mean RV/LV diameter ratio decreased from baseline to 48 h post-procedure (1.55 vs. 1.13; mean difference, -0.42; p < 0.0001). Mean pulmonary artery systolic pressure (51.4 mm Hg vs. 36.9 mm Hg; p < 0.0001) and modified Miller Index score (22.5 vs. 15.8; p < 0.0001) also decreased post-procedure. One GUSTO (Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries)-defined severe bleed (groin hematoma with transient hypotension) and 16 GUSTO-defined moderate bleeding events occurred in 15 patients (10%). No patient experienced intracranial hemorrhage. CONCLUSIONS: Ultrasound-facilitated, catheter-directed, low-dose fibrinolysis decreased RV dilation, reduced pulmonary hypertension, decreased anatomic thrombus burden, and minimized intracranial hemorrhage in patients with acute massive and submassive PE. (A Prospective, Single-arm, Multi-center Trial of EkoSonic® Endovascular System and Activase for Treatment of Acute Pulmonary Embolism (PE) [SEATTLE II]; NCT01513759).