Recanalization and flow regulate venous thrombus resolution and matrix metalloproteinase expression in vivo

The background and role of catheter-directed thrombolysis evolving procedures for acute iliofemoral deep venous thrombosis

Minimal invasive treatment such as early endovenous thrombus removal for iliofemoral deep venous thrombosis (DVT) emerged in the end of last century. The principle is catheter-directed thrombolysis (CDT) using either plasminogen activating agents alone, as ultrasound-assisted CDT, or in combination with mechanical devices as pharmaco-mechanical CDT. The interest for this treatment modality is the high rate of post-thrombotic syndrome (PTS) with anticoagulation (AC) alone, especially after iliofemoral DVT. Recently published randomized controlled trials (RCTs) comparing early thrombus removal with AC alone, as well as non-randomized studies, have demonstrated favorable rates, or at least a decrease of moderate and severe PTS, in favor of these procedures. This article will summarize the background and evolution of the procedures in the last three decades and discuss fundamental criteria for inclusion and exclusion, focusing on the procedures regarding thrombus age and location, technical issues, complications and results including different outcome measures for PTS, for which iliac DVT involvement is a massive risk factor to be prevented.

Suprarenal Inferior Vena Cava Filter Placement and Retrieval: Safety Analysis

PURPOSE

To evaluate safety and retrieval success of retrievable suprarenal inferior vena cava (IVC) filters.

MATERIALS AND METHODS

A retrospective chart review of patients who received a retrievable suprarenal IVC filter between January 2008 and December 2017 was conducted. Suprarenal IVC filters were placed in 24 female and 27 male patients. The most common indications for filter placement were IVC thrombus (n = 20; 39.2%) and iliofemoral venous thrombosis with contraindication to anticoagulation (n = 16; 31.3%). The most common indications for suprarenal placement were IVC thrombus (n = 20; 39.2%), anatomic variants (n = 17; 33.3%), and external IVC compression (n = 8; 15.8%). Duplicated IVC was the most common anatomic variant requiring suprarenal placement (n = 7; 13.7%).

RESULTS

Günther Tulip (n = 40; 78.4%), Denali (n = 10; 19.6%), and Celect (n = 1; 2.0%) filters were used. Retrieval was attempted in 27 of the 51 filters placed (52.9%). Of the 27 attempted retrievals, the technical success rate was 100% (27/27). The median dwell time was 87.0 days (95% confidence interval, 28-137 d). One complication involving fractured struts during filter retrieval occurred. No significant change in craniocaudal filter position, lateral filter tilt, or renal function between placement and retrieval was observed (P < .05). There were no instances of indwelling filter fracture.

CONCLUSIONS

Suprarenal IVC filters, when indicated, can be placed and retrieved with a low complication rate.

Early growth response factor-1 DNA enzyme 1 inhibits the formation of abdominal aortic aneurysm in rats

The aim of the present study was to characterize the effects of early growth response factor-1 DNA enzyme (EDRz) in a rat abdominal aortic aneurysm (AAA) model to determine the mechanism by which EDRz inhibits AAA and affects the formation of AAA by regulating the activity of matrix metalloproteinase (MMP)-2 and MMP-9. EDRz was transfected into the abdominal aorta of rats using the jetPRIME transfection reagent following infusion with elastase. Fluorescent microscopy, hematoxylin and eosin staining, ultrastructural analysis, reverse transcription-quantitative polymerase chain reaction, western blotting and immunohistochemical analysis were performed to characterize the response to EDRz. The EDRz group showed minimal aneurysm formation when compared with the control group, with significantly lower aortic diameter expansion (2.5±0.1 vs. 3.5±0.1 mm; P<0.05). Early growth response factor 1 (Egr-1) mRNA and protein levels were significantly decreased in the EDRz group, as expected. The decrease in Egr-1 was accompanied by decreases in the mRNA and protein levels of MMP-2 and MMP-9 (P<0.05). Transfection of the Egr-1 specific synthetic DNA enzyme EDRz significantly reduced AAA following elastase infusion in rats, at least in part due to the decreased expression of downstream MMP-2 and MMP-9.

Serpins in Venous Thrombosis and Venous Thrombus Resolution

Several serpins function as potent inhibitors of thrombolytic serine proteases. Venous thrombosis is a common and debilitating condition whose incidence is on the rise. Studies using genetically modified mice and inhibitors have shown that the plasminogen activator inhibitors (PAI), PAI-1 and PAI-2, are primary regulators of plasminogen activation and contribute to regulating the resolution of experimental venous thrombi, via inflammatory mechanisms, vascular remodeling, and inhibition of fibrinolysis. Therapies to accelerate venous thrombus resolution would be beneficial, since delayed or incomplete clot resolution frequently leads to postthrombotic syndrome, a long-term complication associated with debilitating limb swelling, pain, and recurrent skin ulceration. Here we describe a useful and reproducible mouse model for the study of venous thrombus resolution involving ligation of the inferior vena cava and elucidation of the molecular and cellular determinants of venous thrombus formation and resolution.

Great Saphenous Vein Flow Pattern as a Simple Ultrasonographic Sign of Early Recanalization of Deep Vein Thrombosis: A Case Series Report

We retrospectively examined patients with ultrasonographically occlusive acute proximal deep vein thrombosis (DVT). All patients were categorized into two groups on the basis of whether great saphenous vein (GSV) flow toward the common femoral vein was detected (flow [+]; n=10) or undetected (flow [−]; n=10). We investigated the relationship between the GSV flow pattern and DVT recanalization. Thrombus recanalization, which is defined as diameter reduction to lower than 40% of the vessel diameter, was confirmed in seven of the flow (+), and none of the flow (−). This study proposes that the GSV flow pattern may be a simple marker for the recanalization of proximal occlusive DVT.

Plasma MMP and TIMP evaluation in patients with deep venous thrombosis: could they have a predictive role in the development of post-thrombotic syndrome?

Post-thrombotic syndrome (PTS) is a condition that can develop in about half of the patients with deep vein thrombosis (DVT) of lower limbs. In the present study, we evaluated the expression of inflammatory biomarkers in the early phases of DVT and their correlation with the onset of PTS. Patients were enrolled after the first episode of DVT and were followed up for 1, 4, 8, 12 and 18 months. At each visit, blood sample was collected to evaluate plasma levels of matrix metalloproteinase (MMP)-1,-2,-3,-7,-8 and -9 MMP inhibitors, TIMP-1,-2, neutrophil gelatinase-associated lipocalin (NGAL) and cytokines TNF-α and IL-6. Analysis included 201 patients [86 males (42·79%) and 115 females (57·21%); average age 56 ± 7 years]. Of the 201 patients, 47 (23·38%; 21 males, 26 females) developed PTS during the follow-up period. The control group was made up of 60 individuals without DVT (22 males and 38 females). High plasma levels of MMPs, NGAL and cytokines were recorded during the acute phase after DVT. Moreover, patients with PTS showed higher levels of MMP-1 and MMP-8 with respect to patients without PTS. There is a close relationship between DVT, the individual risk of PTS and specific biomarkers such as MMPs and other related molecules, which may help guide prevention and therapy based on the patient's individual risk profile, and has to be studied in future.