Medium-term outcomes of EXTra-design engineering inner-branch ENdografts for the treatment of complex aortic aneurysms from a multicenter collaboration.

OBJECTIVE: This study aims to present the medium-term outcomes of Extra-Design engineering endografts with inner branches (EDE-iBEVARs, Artivion) in endovascular aortic repairs of complex aneurysms building upon promising early results. METHODS: A retrospective, international, multi-center study was conducted including consecutive patients who underwent complex endovascular aortic repairs using EDE-iBEVARs between 2018 and 2022. Patient demographics, aneurysm anatomical features, procedural details, reinterventions, complications, and endograft failures during follow-up were assessed. The primary outcome was aneurysm-related mortality. Secondary outcome measures included the freedom from all-cause mortality and reintervention, technical and clinical success, and late related complications including branch instability, endoleaks, and serious adverse events. RESULTS: Our study encompassed a total of 260 patients across 13 European centers. The cohort included patients with thoracoabdominal aortic aneurysms (n = 116), suprarenal or juxta-renal aneurysms (n = 95), and those who had previous open repair or previous endovascular aortic repair with type 1A endoleak (n = 49). Of 982 possible inner branches (937 antegrade and 45 retrograde), 962 (98%) were successfully cannulated and bridged with covered stents during the index procedure. Overall, the endograft was successfully deployed in 98% of patients, and 93% were discharged from hospital following surgery. At 3 years, freedom from aneurysm-related mortality was 97%, whereas the freedom of all-cause mortality was 89%. Freedom from reinterventions was 91% and 76% at 1 and 3 years, respectively. The rate of late complications such as endoleaks or branch instability events was 12% (n = 30). The late branch occlusion rate during follow-up was 1.5% (n = 15), of which 12 were renal branches. CONCLUSIONS: EDE-iBEVARs demonstrate satisfactory medium-term outcomes with reintervention rates comparable to other endografts. Encouragingly, rates of branch patency were high, and major adverse events were low. This technology could expand the treatment options for patients with challenging complex aortic conditions.

Intra-arterial Fractional Flow Reserve Measurements Provide an Objective Assessment of the Functional Significance of Peripheral Arterial Stenoses.

OBJECTIVE: Peripheral arterial stenoses (PAS) are commonly investigated with duplex ultrasound (DUS) and angiography, but these are not functional tests. Fractional flow reserve (FFR), a pressure based index, functionally assesses the ischaemic potential of coronary stenoses, but its utility in PAS is unknown. FFR in the peripheral vasculature in patients with limb ischaemia was investigated. METHODS: Patients scheduled for angioplasty and or stenting of isolated iliac and superficial femoral artery stenoses were recruited. Resting trans-lesional pressure gradient (Pd/Pa) and FFR were measured after adenosine provoked hyperaemia using an intra-arterial 0.014 inch flow and pressure sensing wire (ComboWire XT, Philips). Prior to revascularisation, exercise ABPI (eABPI) and DUS derived peak systolic velocity ratio (PSVR) of the index lesion were determined. Calf muscle oxygenation was measured using blood oxygenation level dependent cardiovascular magnetic resonance prior to and after revascularisation. RESULTS: Forty-one patients (32, 78%, male, mean age 65 ± 11 years) with 61 stenoses (iliac 32; femoral 29) were studied. For lesions < 80% stenosis, resting Pd/Pa was not influenced by the degree of stenosis (p = .074); however, FFR was discriminatory, decreasing as the severity of stenosis increased (p = .019). An FFR of < 0.60 was associated with critical limb threatening ischaemia (area under the curve [AUC] 0.87; 95% CI 0.75 - 0.95), in this study performing better than angiographic % stenosis (0.79; 0.63 - 0.89), eABPI (0.72; 0.57 - 0.83), and PSVR (0.65; 0.51 - 0.78). FFR correlated strongly with calf oxygenation (rho, 0.76; p < .001). A greater increase in FFR signalled resolution of symptoms and signs (ΔFFR 0.25 ± 0.15 vs. 0.13 ± 0.09; p = .009) and a post-angioplasty and stenting FFR of > 0.74 predicted successful revascularisation (combined sensitivity and specificity of 95%; AUC 0.98; 0.91 - 1.00). CONCLUSION: This pilot study demonstrates that FFR can objectively measure the functional significance of PAS that compares favourably with visual and DUS based assessments. Its role as a quality control adjunct that confirms optimal vessel patency after angioplasty and or stenting also merits further investigation.

Long-Term Effects of Acute Kidney Injury Following Endovascular Femoropopliteal Intervention: Insights From a Multicenter Trial.

PURPOSE: To examine the association between acute kidney injury (AKI) severity and duration with cardiovascular mortality, following endovascular treatment of femoropopliteal disease, and whether it is AKI in itself that confers an increased risk of cardiovascular mortality. METHODS: A retrospective analysis of prospectively collected data obtained between 2014 and 2019 from 3 vascular centers. Renal function was followed up for a minimum of 90 days. Electronic records were queried to establish a cause of death, where applicable. Patients were excluded if unable to provide written informed consent or if presenting with acute limb ischemia. Primary outcomes were the hazard ratios for cardiovascular death (AKI patients vs no AKI; no AKI vs stage 1 AKI vs stage 3 AKI; and no AKI vs transient AKI vs established AKI). Propensity score-matched analysis was used to establish whether developing AKI, in patients with similar demographics and procedural characteristics, is associated with a higher risk of cardiovascular death. RESULTS: Overall 239 patients developed AKI, and this was associated with an increased risk of cardiovascular mortality (hazard risk [HR]: 4.3, 95% confidence intervals [CIs]: 2.1-6.8, pairwise comparison p value=0.006]. This was dependent on the severity of the AKI stage (HR 5.4, 95% CI: 2.4-7.3, pairwise comparison p value=0.01) and duration (HR 4.2, 95% CI: 2.3-6.2, pairwise comparison p value=0.04). The propensity score-matched analysis showed that even when patients are matched for comorbidity and procedural characteristics, AKI confers an increased risk of mortality (p=0.04). CONCLUSIONS: Acute kidney injury is common after femoropopliteal endovascular therapy. It confers an increased risk of long-term cardiovascular mortality, which is still present when renal decline is transient, and highest for patients with established decline in renal function. CLINICAL IMPACT: This is the first study in the setting of peripheral arterial disease to show that acute kidney injury has an adverse effect on cardiovascular mortality, in the long-term, that is dependent on its severity, and present even when the AKI is transient. We have also shown that this difference in cardiovascular mortality becomes more pronounced from the medium-term, and thus closer follow-up of these patients is required.

A Systematic Review and Meta-Analysis of 12-Month Patency After Intervention for Iliofemoral Obstruction Using Dedicated or Non-Dedicated Venous Stents.

BACKGROUND: Endovascular stenting of the deep venous system has been proposed as a method to treat patients with symptomatic iliofemoral outflow obstruction. The purpose of this systematic review and meta-analysis was to compare the effectiveness of this treatment at 1-year following the development of dedicated venous stents. METHOD AND RESULTS: We searched MEDLINE and EMBASE for studies evaluating the effectiveness of venous stent placement. Data were extracted by disease pathogenesis: non-thrombotic iliac vein lesions (NIVL), acute thrombotic (DVT), or post-thrombotic syndrome (PTS). Main outcomes included technical success, stent patency at 1 year and symptom relief. A total of 49 studies reporting outcomes in 5154 patients (NIVL, 1431; DVT, 950; PTS, 2773) were included in the meta-analysis. Technical success rates were comparable among groups (97%-100%). There were no periprocedural deaths. Minor bleeding was reported in up to 5% of patients and major bleeding in 0.5% upon intervention. Transient back pain was noted in 55% of PTS patients following intervention. There was significant heterogeneity between studies reporting outcomes in PTS patients. Primary and cumulative patency at 1 year was: NIVL-96% and 100%; DVT-91% and 97%; PTS (stents above the ligament)-77% and 94%, and; PTS (stents across the ligament)-78% and 94%. There were insufficient data to compare patency outcomes of dedicated and nondedicated venous stents in patients with acute DVT. In NIVL and PTS patients, stent patency was comparable at 1 year. There was inconsistency in the use of validated tools for the measurement of symptoms before and after intervention. When reported, venous claudication, improved in 83% of PTS patients and 90% of NIVL patients, and ulcer healing occurred in 80% of PTS patients and 32% of NIVL patients. CONCLUSIONS: The first generation of dedicated venous stents perform comparably in terms of patency and clinical outcomes to non-dedicated technologies at 1 year for the treatment of patients with NIVL and PTS. However, significant heterogeneity exists between studies and standardized criteria are urgently needed to report outcomes in patients undergoing deep venous stenting.

Medium Term Outcomes of Deep Venous Stenting in the Management of Venous Thoracic Outlet Syndrome.

OBJECTIVE: Venous thoracic outlet syndrome (vTOS) is a relatively rare condition associated with significant morbidity. Its management continues to evolve, with increasing use of endovascular adjuncts, such as percutaneous thrombectomy and angioplasty, in addition to first rib resection. The utility of stenting residual venous stenotic lesions is poorly defined within the literature. This study sought to review the medium term patency rates of upper limb deep venous stenting in the management of vTOS. METHODS: A single centre, retrospective review of patients managed for vTOS with first rib resection followed by upper limb deep venous stenting between January 2012 and February 2021 was conducted. Post-procedural ultrasounds were reviewed to determine stent patency. RESULTS: Twenty-six patients were included, with 33 stents placed. The median duration of follow up was 50 months. On venous duplex ultrasound at three years post-operatively, primary patency rates were 66%, primary assisted patency rates were 88%, secondary patency rates were 91%, and total occlusion rates were 9%. After stent placement, 80% of patients remained asymptomatic with regard to compression symptoms. CONCLUSION: Upper limb deep venous stenting is an effective adjunct to surgical decompression in the management of vTOS. Stent medium term patency rates are promising; however, further studies with longer follow up and larger cohorts with multicentre results are required to confirm these early findings.

Performance of Open and Closed Cell Laser Cut Nitinol Stents for the Treatment of Chronic Iliofemoral Venous Outflow Obstruction in Patients Treated at a Single Centre.

OBJECTIVE: A number of dedicated self expanding nitinol stents have been developed for use in the venous system, with both open cell (OC) and closed cell (CC) designs available. Data comparing these different designs are lacking. The objective of this study was to evaluate outcomes in patients treated with open and closed cells for unilateral chronic iliac vein obstruction. METHODS: A single centre retrospective cohort study was conducted, including all patients treated with a dedicated nitinol venous stent between 2014 and 2019. Stent patency and details of re-interventions (including lysis, venoplasty, reinforcement, extension, arteriovenous fistula formation) were examined in the first post-operative year. Subgroup analysis described outcomes for patients treated with OC and CC stents ending above the inguinal ligament and those who required extension into the common femoral vein. Cox regression analysis was used to identify factors associated with loss of primary patency. RESULTS: A total of 207 patients were included (OC 100 patients, CC 107 patients). There was no significant difference between the groups for age (OC 42 years, CC 44 years); gender (OC and CC 67% female); presence of post-thrombotic lesions (OC 71%, CC 73%); stenting across the inguinal ligament (OC 58%, CC 56%), or presence of inflow disease (OC 49%, CC 47%). Primary and cumulative patency at 12 months were similar between groups (primary: OC 63%, CC 65%; cumulative: OC 93%, CC 90%). Patients with a CC stent across the inguinal ligament had a greater risk of needing multiple re-interventions at one year compared with those with an OC stent (odds ratio 2.84, 95% confidence interval [CI] 1.16 - 6.9) but overall, the only factor significantly associated with loss of primary patency was inflow vessel disease (hazard ratio 3.39, 95% CI 1.73 - 6.62, p < .001). CONCLUSION: OC and CC dedicated nitinol venous stents were observed to perform similarly in terms of patency and symptom improvement at one year. Disease of the inflow vessels was the most important factor associated with a loss of stent patency irrespective of stent design.

Use of the Off-The-Shelf Pre-Cannulated E-Nside Endograft to Overcome Anatomical Challenges in Urgent Complex Endovascular Aortic Repair.

Treatment options for large or symptomatic complex aortic aneurysms that require urgent intervention remain limited. Patient factors and comorbidities often make open surgery unappealing, leading to increasing interest in endovascular solutions that can be employed in the urgent setting, such as off-the-shelf endografts. The E-nsideTM (Jotec GmbH, Hechingen, Germany) is a new off-the-shelf endograft with 4 pre-cannulated inner branches that has recently become available in Europe. We report the urgent treatment of 2 large complex aortic aneurysms using this device and discuss the benefits of this new technology. The E-nside off-the-shelf endograft with inner branches is a useful addition to our treatment options for complex aortic aneurysms, particularly those with a narrow aortic lumen. Pre-cannulation of branches provides consistent access to the branches and a readily available option for establishment of a through and through wire for added stability during cannulation and bridging stent-grafts placement. The design of inner branches provides flexibility during deployment of the endograft and cannulation of the target vessels in varied, challenging anatomies.

Early outcomes of Jotec inner-branched endografts in complex endovascular aortic aneurysm repair.

OBJECTIVE: Complex aortic endografts have evolved to include inner branches to overcome specific challenges with existing technologies. We have reported the early outcomes of endovascular aortic aneurysm repair (EVAR) using a Jotec inner branched endograft (iBEVAR). METHODS: All patients who had undergone complex EVARs using extra-design engineering iBEVAR (Jotec GmbH, Hechingen, Germany) from 2018 to 2020 at a single center were reviewed. The patient demographics, cardiovascular risk factors, anatomic features of the aneurysms, and target vessels were recorded. The reasons for using inner branches instead of fenestrated and standard branched endografts and the procedural details, outcomes, and reintervention during follow-up were examined. RESULTS: A total of 110 patients were treated with branched and fenestrated endografts during the study period, of whom 18 patients had had a patient-specific custom-made iBEVAR endograft with downward inner branches. The technical success rate was 100%. A total of 68 target vessels were cannulated, and bridging stent-grafts were placed successfully in all. The reasons for choosing the iBEVAR design included unfavorable target vessel trajectory for fenestrated repair (n = 15), excessive infrarenal aortic angulation and/or adverse iliac access vessels for fenestrated repair (n = 11), the presence of a narrow aortic lumen (n = 14), and/or to reduce aortic coverage compared with that with standard outer branched repair (n = 14). We also used iBEVAR to treat type Ia endoleaks after failed EVAR with a short main body (n = 5). The median contrast volume used was 120 mL (range, 48-200 mL), with a median fluoroscopy screening time of 66 minutes (range, 35-136 minutes) and a median dose-area product of 17,832 dGy∙cm2 (range, 8260-55,070 dGycm2). No 30-day mortality and no major complications occurred. One early intervention was required for a suspected type Ib endoleak from an iliac limb and one late intervention for in-stent stenosis in a renal bridging stent-graft. One patient had died of non-aortic-related causes at 3 months. All other patients continued with follow-up with their aneurysms excluded, patent target vessels, and no type I or III endoleak identified at a median follow-up of 12 months (range, 1-26 months). CONCLUSIONS: The use of Jotec extra-design engineering endografts incorporating downward inner branches resulted in satisfactory early outcomes with a low reintervention rate. The technology has the potential to be a useful addition to our armamentarium for treating complex aortic endografts; however, long-term outcomes data are needed.

Choosing a Mouse Model of Venous Thrombosis.

Murine models are widely used valuable tools to study deep vein thrombosis. Leading experts in venous thrombosis research came together through the American Venous Forum to develop a consensus on maximizing the utility and application of available mouse models of venous thrombosis. In this work, we provide an algorithm for model selection, with discussion of the advantages, disadvantages, and applications of the main mouse models of venous thrombosis. Additionally, we provide a detailed surgical description of the models with guidelines to validate surgical technique.

Paclitaxel and Mortality Following Peripheral Angioplasty: An Adjusted and Case Matched Multicentre Analysis.

OBJECTIVE: Paclitaxel based drug coated balloons (DCBs) and drug eluting stents (DESs) may be associated with increased mortality in patients with peripheral arterial occlusive disease (PAOD), based on a recent meta-analysis. This study, however, had a number of limitations, which have been discussed at great length among the vascular community. The aim of this research was to assess the association between paclitaxel based endovascular treatment (PTX) in the femoropopliteal (F-P) segment and mortality, adjusting for relevant risk factors and including patients with chronic limb threatening ischaemia (CLTI). METHODS: This was a retrospective cohort study of a prospectively maintained multicentre (three sites) database of patients with claudication or CLTI. Patients having F-P angioplasty between 1 January 2014 and 30 May 2019 with or without PTX were included. Survival was compared in Cox regression analyses adjusted for parameters of the Charlson comorbidity index. A separate nested case matched (based on each individual's Charlson index) analysis was performed to compare mortality rates between those who received PTX and those who did not. RESULTS: A total of 2 071 patients were analysed: 966 patients (46.6%) were treated with PTX (952 [46%] had CLTI and 1 119 [54%] severe claudication [Rutherford stage 3]). Over a 24 month median follow up, 456 (22.1%) patients died. Using multivariable Cox regression, PTX was not associated with mortality (HR 0.94, p = .46), even when assessed separately for those with intermittent claudication (HR 1.30, p = .15) or CLTI (HR 0.81, p = .060). In the case matched analysis (885 matched pairs of patients), PTX was not associated with mortality (HR 0.89, p = .17). Paclitaxel dose and use of a DCB or DES were not associated with mortality in any subanalysis. CONCLUSION: When relevant risk factors were taken into account, there were no associations between PTX and mid term mortality in patients with PAOD.

AngioJet Pharmacomechanical Thrombectomy and Catheter Directed Thrombolysis vs. Catheter Directed Thrombolysis Alone for the Treatment of Iliofemoral Deep Vein Thrombosis: A Single Centre Retrospective Cohort Study.

OBJECTIVE: Percutaneous thrombus removal is used for the treatment of iliofemoral deep vein thrombosis (DVT), but the efficacy of different treatment modalities has not yet been determined. The aim of this study was to compare the outcomes of patients treated with additional AngioJet pharmacomechanical thrombectomy (PCDT) vs. catheter directed lysis (CDT) alone. METHODS: A retrospective review of all patients who received thrombolysis for the treatment of symptomatic acute iliofemoral DVT between 2011 and 2017 was carried out. Outcome measures included the incidence of post-thrombotic syndrome (PTS), procedural outcomes (lytic exposure), the incidence of complications, and vessel patency. All patients were followed up for a minimum of one year. RESULTS: A total of 151 limbs were treated, 70 limbs with PCDT and 81 limbs with CDT alone. Demographic data and prevalence of risk factors were comparable. Incidence of PTS (Villalta score at one year) showed no significant difference (22.2% PCDT vs. 24.7% CDT alone, p = .74). Use of PCDT resulted in a non-statistically significant trend for fewer bleeds (n = 4/63 [6.3%] vs. 13/76 [17.1%]; relative risk 0.37, 95% confidence interval [CI] 0.13-1.08; p = .07), a statistically significant reduction in lysis duration (40 h [95% CI 34-46] vs. 53 h [95% CI 49-58]; p < .001) and a reduction in lytic dose (49 mg [95% CI 42-55] vs. 57 mg [95% CI 52-61]; p = .011) compared with CDT. This reduction was accentuated in 24 cases primarily treated with AngioJet PowerPulse mode (27 h, 95% CI 20-34 [p < .001] and 42 mg, 95% CI 34-50 [p = .009]). Incidences of complications were comparable between groups, with one death due to an intracranial haemorrhage following CDT. Although the incidence of haemoglobinuria was increased following PCDT (12/63 [19.0%] vs. 3/76 [3.9%]; p = .006), no significant difference in acute kidney injury was observed (3/63 [4.8%] vs. 1/76 [1.3%]; p = .33). No significant difference in vessel patency over two years was observed (p = .73). CONCLUSION: The use of PCDT for the treatment of iliofemoral DVT was observed to provide comparable patient outcomes, comparable vessel patency, an acceptable safety profile, and reduced overall lytic dose.

Reactive Oxygen Species in Venous Thrombosis.

Reactive oxygen species (ROS) have physiological roles as second messengers, but can also exert detrimental modifications on DNA, proteins and lipids if resulting from enhanced generation or reduced antioxidant defense (oxidative stress). Venous thrombus (DVT) formation and resolution are influenced by ROS through modulation of the coagulation, fibrinolysis, proteolysis and the complement system, as well as the regulation of effector cells such as platelets, endothelial cells, erythrocytes, neutrophils, mast cells, monocytes and fibroblasts. Many conditions that carry an elevated risk of venous thrombosis, such as the Antiphospholipid Syndrome, have alterations in their redox homeostasis. Dietary and pharmacological antioxidants can modulate several important processes involved in DVT formation, but their overall effect is unknown and there are no recommendations regarding their use. The development of novel antioxidant treatments that aim to abrogate the formation of DVT or promote its resolution will depend on the identification of targets that enable ROS modulation confined to their site of interest in order to prevent off-target effects on physiological redox mechanisms. Subgroups of patients with increased systemic oxidative stress might benefit from unspecific antioxidant treatment, but more clinical studies are needed to bring clarity to this issue.

Radiation-Induced DNA Damage in Operators Performing Endovascular Aortic Repair.

BACKGROUND: Radiation exposure during fluoroscopically guided interventions such as endovascular aortic repair (EVAR) is a growing concern for operators. This study aimed to measure DNA damage/repair markers in operators perfoming EVAR. METHODS: Expression of the DNA damage/repair marker, γ-H2AX and DNA damage response marker, phosphorylated ataxia telangiectasia mutated (pATM), were quantified in circulating lymphocytes in operators during the peri-operative period of endovascular (infrarenal, branched, and fenestrated) and open aortic repair using flow cytometry. These markers were separately measured in the same operators but this time wearing leg lead shielding in addition to upper body protection and compared with those operating with unprotected legs. Susceptibility to radiation damage was determined by irradiating operators' blood in vitro. RESULTS: γ-H2AX and pATM levels increased significantly in operators immediately after branched endovascular aortic repair/fenestrated endovascular aortic repair (P<0.0003 for both). Only pATM levels increased after infrarenal endovascular aortic repair (P<0.04). Expression of both markers fell to baseline in operators after 24 hours (P<0.003 for both). There was no change in γ-H2AX or pATM expression after open repair. Leg protection abrogated γ-H2AX and pATM response after branched endovascular aortic repair/fenestrated endovascular aortic repair. The expression of γ-H2AX varied significantly when operators' blood was exposed to the same radiation dose in vitro (P<0.0001). CONCLUSIONS: This is the first study to detect an acute DNA damage response in operators performing fluoroscopically guided aortic procedures and highlights the protective effect of leg shielding. Defining the relationship between this response and cancer risk may better inform safe levels of chronic low-dose radiation exposure.

Two Year Outcome After Chronic Iliac Vein Occlusion Recanalisation Using the Vici Venous Stent®.

OBJECTIVE/BACKGROUND: The aim was to assess two year outcomes with placement of the Vici Venous Stent® in patients with chronic iliofemoral venous occlusions (complete blockage). METHODS: This was a retrospective single centre study comprising patients treated with the Vici Venous Stent for venographically verified iliofemoral venous occlusion and post-thrombotic syndrome (Villalta score ≥ 5 points) at least 12 months after acute deep vein thrombosis. Venography and intravascular ultrasound were used peri-operatively; duplex ultrasound was used to assess stent patency during follow up. RESULTS: Eighty-eight patients (101 limbs) had stent placement between March 2014 and October 2016. Median pre-treatment Villalta score was 14 (range 5-33). Stenting extended across the inguinal ligament in 63 limbs (62%) in order to land in a healthy venous segment. Six patients (7%) required endophlebectomy and fistula creation. Median imaging follow up was 21 months (range 0-41 months). Primary, assisted primary and secondary patency rates at one year were 59%, 78%, and 87%, respectively, and two years 51%, 73%, and 82%, respectively. Forty-three limbs (43%) had re-intervention (lysis, venoplasty, and/or placement of stent) during follow up; median time to re-intervention was 32 days (range 0-520 days). At 24 months, 37 of 53 limbs (70%) with available Villalta assessment showed clinically significant improvement (>30% reduction of baseline score). Villalta scores at the 6, 12, and 24 month clinical follow up were significantly lower than before stenting (p < .001, all time points). In a subset analyses of limbs with stenting terminating above and below the inguinal ligament, secondary cumulative patency rates at 24 months were 90% and 79%, respectively; clinical outcome showed 58% vs. 73% of limbs with clinically significant improvement, respectively. There was no statistically significant difference in patency or clinical outcomes. CONCLUSION: The Vici Venous Stent is associated with a good secondary patency rate and durable and substantial symptomatic resolution in patients with chronic post-thrombotic occlusions, regardless of whether stents extended beneath the inguinal ligament.

Assessment of Venous Thrombosis in Animal Models.

Deep vein thrombosis and common complications, including pulmonary embolism and post-thrombotic syndrome, represent a major source of morbidity and mortality worldwide. Experimental models of venous thrombosis have provided considerable insight into the cellular and molecular mechanisms that regulate thrombus formation and subsequent resolution. Here, we critically appraise the ex vivo and in vivo techniques used to assess venous thrombosis in these models. Particular attention is paid to imaging modalities, including magnetic resonance imaging, micro-computed tomography, and high-frequency ultrasound that facilitate longitudinal assessment of thrombus size and composition.

Cancer-Associated Thrombosis: Regulatory Mechanisms and Emerging Directions.

Venous thrombosis is a common complication in cancer patients, and some cancer chemotherapies are associated with an increased risk of venous thromboembolism. The regulatory mechanisms that control thrombus formation and subsequent resolution in patients with cancer, however, are incompletely understood, and novel treatments for cancer-associated thrombosis may arise from a better understanding of such mechanisms. In this chapter, pathways that regulate cancer-associated thrombus formation are outlined, and the effects of anti-angiogenic cancer chemotherapies on venous thrombus resolution are highlighted. Potentially pro-thrombotic effects of anti-angiogenic agents are important considerations when managing the complications of venous thrombosis in cancer patients.