Prospective determination of candidates for thrombolysis in patients with acute proximal deep vein thrombosis

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.

Coagulation factor XIII-A and activated FXIII-A decrease in some deep vein thrombosis patients following catheter-directed thrombolysis

: The objective of the study was to assess the effect of tissue plasminogen activator administered during catheter-directed thrombolysis (CDT) on coagulation factor XIII (FXIII). Thrombolytic therapy carries significant risks, such as life-threatening bleeds. The mechanisms responsible for major bleeds and intracerebral hemorrhages during thrombolysis are not fully understood. Activated FXIII (FXIII-A) lies at the intersection of coagulation and fibrinolysis. Using purified proteins and blood collected from nine deep vein thrombosis patients undergoing CDT, the stability of FXIII-A and FXIII were measured immediately before, immediately after and 1-day post thrombolysis. We found that purified tissue plasminogen activator directly degraded FXIII-A. During CDT, FXIII levels were decreased by more than 40% in five of nine patients and FXIII-A levels were decreased by more than 85% in two patients when it was activated. FXIII-A and FXIII-A can decrease during CDT in some patients, warranting further research into the role of FXIII-A in bleeding from thrombolysis.

Present and future options for treatment of infrainguinal deep vein disease

OBJECTIVE

Management of chronic deep vein disease focuses on the alleviation of reflux and obstruction. For the suprainguinal veins, the main underlying pathologic process is obstruction, which has been recognized as a significant contributor to chronic venous insufficiency. This is currently being addressed with venous stenting and the development of dedicated stents designed for this segment of the venous system. Treatment of the femoropopliteal vein (FPV) is far more challenging because of the idiosyncratic anatomy, the hemodynamic physiology, and the technical aspects of size mismatch and valve flow dynamics in managing deep venous reflux. This review article discusses traditional and emerging technologies to treat infrainguinal disease.

METHODS

Previous and current articles addressing this issue were reviewed. Emphasis was placed on emerging techniques and technologies.

RESULTS

Significant bench work, in vitro and in vivo studies, have been conducted over the last 40 years addressing the issue of infrainguinal reflux and obstruction. Historically, open procedures to address FPV reflux and obstruction have had variable success in a few centers around the world. The significant increase of emerging endovascular therapies may allow more appropriate, reproducible, widespread treatment of infrainguinal deep venous disease.

CONCLUSIONS

Adequate and durable therapies for infrainguinal venous disease represent one of the greatest challenges for a vein specialist. Recently, a cluster of interest and techniques/technologies have been developed. The endovascular management of arterial disease is mature. The endovenous management of infrainguinal disease is on the cusp of meaningful innovation. The purpose of this evidence summary is to describe the options for the management of chronic FPV disease, with emphasis on emerging technologies and techniques.

Malignancy Does not Affect Outcomes of Pharmacomechanical Thrombolysis in Acute Symptomatic Iliofemoral Deep Vein Thrombosis

BACKGROUND

Cancer patients demonstrate increased risk for venous thromboembolism (VTE), VTE recurrence, and anticoagulation-associated bleeding. Pharmacomechanical thrombolysis (PMT) aand thrombectomy improves venous patency, venous valve function, and quality of life in patients with acute iliofemoral deep vein thrombosis (DVT). It remains unknown whether pharmacomechanical thrombolysis can be used safely in patients with active cancer. We hypothesized that perioperative and short-term outcomes of pharmacomechanical iliofemoral DVT thrombolysis would not differ between patients with cancer and those without cancer.

METHODS

A retrospective chart review of consecutive patients with symptomatic iliofemoral DVT undergoing PMT by AngioJet Power Pulse spray and thrombectomy at a single tertiary care university institution between December 2013 and December 2016 was performed. Outcomes between patients with cancer and without cancer were compared.

RESULTS

We identified 22 limbs in 18 consecutive patients: 6 patients (7 limbs) with cancer and 12 patients (15 limbs) without cancer. Between these groups, the mean age was 60.5 ± 4.3 vs. 53.8 ± 26.8 years, respectively (P = 0.5593), and females comprised 66.7% vs. 25.0%, respectively (P = 0.0878). No significant difference in inferior vena cava (IVC) involvement between the groups (57.1% vs. 53.3%, P = 0.8676) was noted. Grade II (50-94% lysis) and III (95% complete lysis) thrombus lysis with restoration of venous patency was achieved in both the groups. Overnight catheter-directed thrombolysis (CDT) was rarely used. Notably, stenting was more frequently employed in cancer patients than in those without cancer (57.1% vs. 13.3%, P = 0.0316). The mean duration of follow-up was 3.42 ± 4.41 months for the cancer group and 4.50 ± 2.43 months for the noncancer group (P = 0.5060). Overall outcomes were excellent as no patient in both the groups experienced recurrent DVT, major bleeding, or postthrombotic syndrome. There was no mortality associated with the endovascular thrombolysis procedures.

CONCLUSIONS

The results of our study suggest that the presence of malignancy does not affect short-term outcomes of endovascular thrombolytic therapy in symptomatic DVT. Further follow-up is needed to evaluate long-term outcomes.

Fibrin-targeted magnetic resonance imaging allows in vivo quantification of thrombus fibrin content and identifies thrombi amenable for thrombolysis

OBJECTIVE

Deep venous thrombosis is a major health problem. Thrombolytic therapies are effective in recanalizing the veins and preventing post-thrombotic complications, but there is no consensus on selection criteria. The aim of this study was to investigate a fibrin-specific MRI contrast agent (EP-2104R) for the accurate quantification of thrombus' fibrin content in vivo and for the identification of thrombus suitable for thrombolysis.

APPROACH AND RESULTS

Venous thrombosis was induced in the inferior vena cava of 8- to 10-week-old male BALB/C mice and MRI performed 2, 4, 7, 10, 14, and 21 days later. Eighteen mice were scanned at each time point pre and 2 hours post injection of EP-2104R (8.0 μmol/kg) with 12 mice at each time point used to correlate fibrin contrast uptake with thrombus' histological stage and fibrin content. Six mice at each time point were immediately subjected to intravascular thrombolytic therapy (10 mg/kg of tissue-type plasminogen activator). Mice were imaged to assess response to lytic therapy 24 hours after thrombolytic treatment. Two mice at each time point were scanned post injection of 0.2 mmol/kg of Gd-DTPA (gadolinium with diethylenetriaminepentacetate, Magnevist, Schering AG, Berlin, Germany) for control purpose. Contrast uptake was correlated positively with the fibrin content of the thrombus measured by Western blotting (R(2)=0.889; P<0.001). Thrombus relaxation rate (R1) post contrast and the change in visualized thrombus size on late gadolinium enhancement inversion recovery MRI pre-EP-2104R and post-EP-2104R injection were the best predictors for successful thrombolysis (area under the curve, 0.989 [95% confidence interval, 0.97-1.00] and 0.994 [95% confidence interval, 0.98-1.00] respectively).

CONCLUSIONS

MRI with a fibrin-specific contrast agent accurately estimates thrombus fibrin content in vivo and identifies thrombi that are amenable for thrombolysis.

In vivo magnetization transfer and diffusion-weighted magnetic resonance imaging detects thrombus composition in a mouse model of deep vein thrombosis

BACKGROUND

Deep vein thrombosis remains a major health problem necessitating accurate diagnosis. Thrombolysis is associated with significant morbidity and is effective only for the treatment of unorganized thrombus. We tested the feasibility of in vivo magnetization transfer (MT) and diffusion-weighted magnetic resonance imaging to detect thrombus organization in a murine model of deep vein thrombosis.

METHODS AND RESULTS

Deep vein thrombosis was induced in the inferior vena cava of male BALB/C mice. Magnetic resonance imaging was performed at days 1, 7, 14, 21, and 28 after thrombus induction using MT, diffusion-weighted, inversion-recovery, and T1-mapping protocols. Delayed enhancement and T1 mapping were repeated 2 hours after injection of a fibrin contrast agent. Finally, excised thrombi were used for histology. We found that MT and diffusion-weighted imaging can detect histological changes associated with thrombus aging. MT rate (MTR) maps and percentage of MT rate (%MTR) allowed visualization and quantification of the thrombus protein content, respectively. The %MTR increased with thrombus organization and was significantly higher at days 14, 21, and 28 after thrombus induction (days 1, 7, 14, 21, 28: %MTR=2483±451, 2079±1210, 7029±2490, 10 295±4356, 32 994±25 449; PANOVA<0.05). There was a significant positive correlation between the %MTR and the histological protein content of the thrombus (r=0.70; P<0.05). The apparent diffusion coefficient was lower in erythrocyte-rich and collagen-rich thrombus (0.72±0.10 and 0.69±0.05 [×10(-3) mm(2)/s]). Thrombus at days 7 and 14 had the highest apparent diffusion coefficient values (0.95±0.09 and 1.10±0.18 [×10(-3) mm(2)/s]).

CONCLUSIONS

MT and diffusion-weighted magnetic resonance imaging sequences are promising for the staging of thrombus composition and could be useful in guiding medical intervention.

pharmacomechanical Thrombectomy for Early Thrombus Removal

Objectives:

To review the current literature on the outcomes of pharmacomechanical thrombectomy (PMT) for early thrombus removal in patients with venous thromboembolism (VTE).

Methods:

We searched the MEDLINE database and performed a manual search of the references of selected articles to select reports reporting the outcomes of PMT alone and PMT compared to catheter-direct thrombolysis (CDT). Outcomes of interest included clot lysis rate, incidence of pulmonary embolism, major bleeding, recurrent deep vein thrombosis, number of venograms needed and amount of lytic utilized.

Results

We found nine articles that reported outcomes of PMT. Three devices were utilized for PMT, the Angiojet, Trellis and Helix. Different thrombolytics were used to facilitate thrombus removal including urokinase, reteplase, tecneteplase, and tissue plasminogen activator (t-PA). Complete and partial thrombus removal were achieved in up to 84% and 64% and 81% and 59% of the limbs treated with PMT and CDT alone, respectively. Data on PE and bleeding risk after PMT compared to CDT are scarce. The duration of the thrombolysis process, amount of lytics and number of venograms were substantially reduced in the patients who had PMT compared to those who underwent CDT alone. Two articles evaluated the obstacles that limit the indication of PMT in patients with VTE.

Conclusion:

VTE is a prevalent burden in Western societies. The rationale of early thrombus is to reduce valvular damage and improve venous patency in order to reduce the risk of PTS. PMT is a feasible, safe and faster alternative to expedite the thrombolysis process in patients with VTE.

Postthrombotic vein wall remodeling: preliminary observations

BACKGROUND

Postthrombotic syndrome is characterized by a fibrotic vein injury following deep vein thrombosis (DVT). We sought to quantify the change in vein wall thickness in patients who fail to resolve DVT by 6 months and whether there were differences in blood or plasma levels of inflammatory proteins associated with venous remodeling.

METHODS

Patients presenting with confirmed lower extremity DVT were prospectively recruited for this study. Duplex imaging of the lower extremity venous system was performed, and blood was collected at entrance and repeat evaluation with blood draw and ultrasound imaging at 1 and 6 months. DVT resolution and thickness of the vein wall was quantified by ultrasound imaging in each segment affected by thrombus, and a contralateral, unaffected vein wall served as a control. Gene and protein expression of inflammatory markers were examined from leukocytes and serum, respectively. Analysis of variance or Student t-tests were used, and a P < .05 was significant. N = 10 to 12 for all analyses.

RESULTS

Thirty-two patients (12 patients with DVT resolution at 6 months, 10 patients with persistent thrombus at 6 months, and 10 healthy controls) were compared. Both resolving and nonresolving DVT were associated with a 1.5- to 1.8-fold increased vein wall thickness at 6 months (P = .008) as compared with nonaffected vein wall segments. However, the thickness of the affected segments was 1.4-fold greater in patients who had total resolution of the DVT by 6 months than in patients who had persistent chronic thrombus 6 months after presentation (P = .01). There was a four- to five-fold increased level of matrix metalloproteinase-9 (MMP-9) antigen in thrombosed patients compared with nonthrombosed patient controls (P < .05), while Toll-like receptor-9 (TLR-9) gene expression was three-fold less than controls (P < .05) at enrollment. D-dimer and P-selectin were higher in thrombosed as compared to controls at diagnosis but not at 6 months. Both TLR-4 (marker of inflammation) and P-selectin gene expression were higher in leukocytes from patients with chronic DVT compared with those who resolved at 1 month after diagnosis (P < .05).

CONCLUSIONS

This preliminary study suggests ongoing vein wall remodeling after DVT, measurable by ultrasound and associated with certain biomarkers. At 6 months, the vein wall is markedly thickened and directly correlates with resolution. This suggests that the vein wall response is initiated early following thrombus formation and persists even in the presence of total resolution.