Ovine Iliac Vein Model for Endovascular Thrombectomy of Acute Deep Venous Thrombosis

An ovine iliac vein thrombosis model was devised to test a wall-contacting rotational thrombectomy device. Thrombosis was successfully induced in 9 sheep with an average clot length of 31 mm ± 12 and >60% vessel occlusion on angiography. The thrombus was subsequently removed, maintaining normal intraoperative pulmonary arterial pressure (5.9 mm Hg ± 3.6) and complete distal reperfusion after thrombectomy. Additionally, the sheep were without signs of vascular trauma or embolic complications on gross necropsy and histopathologic analysis. The findings from this study support the use of an ovine iliac deep vein thrombosis model for testing of a lower extremity thrombectomy device.     

Utilization of and Outcomes Associated with Intravascular Ultrasound during Deep Venous Stent Placement among Medicare Beneficiaries

PurposeTo evaluate temporal trends, practice variation, and associated outcomes with the use of intravascular ultrasound (US) during deep venous stent placement among Medicare beneficiaries.Materials and MethodsAll lower extremity deep venous stent placement procedures performed between January 1, 2017, and December 31, 2019 among Medicare beneficiaries were included. Temporal trends in intravascular US use were stratified by procedural setting and physician specialty. The primary outcome was a composite of 12-month all-cause mortality, all-cause hospitalization, or repeat target vessel intervention. The secondary outcome was a composite of 12-month stent thrombosis, embolization, or restenosis.ResultsAmong the 20,984 deep venous interventions performed during the study period, 15,184 (72.4%) utilized intravascular US. Moderate growth in intravascular US use was observed during the study period in all clinical settings. There was a variation in the use of intravascular US among all operators (median, 77.3% of cases; interquartile range, 20.0%–99.2%). In weighted analyses, intravascular US use during deep venous stent placement was associated with a lower risk of both the primary (adjusted hazard ratio, 0.72; 95% confidence interval [CI], 0.69–0.76; P < .001) and secondary (adjusted hazard ratio, 0.32; 95% CI, 0.27–0.39; P < .001) composite end points.ConclusionsIntravascular US is frequently used during deep venous stent placement among Medicare beneficiaries, with further increase in use from 2017 to 2019. The utilization of intravascular US as part of a procedural strategy was associated with a lower cumulative incidence of adverse outcomes after the procedure, including venous stent thrombosis and embolization.     

Impact of anticoagulation status on recanalization and outcome of cerebral venous thrombosis

Effective anticoagulation status may determine the recanalization and outcome of cerebral venous thrombosis (CVT). We report impact of anticoagulation status on recanalization and outcome of CVT. This is a retrospective study on 126 patients with CVT diagnosed on magnetic resonance venography (MRV). Their clinical features and risk factors were noted. The data were retrieved from a prospectively maintained registry, and international normalized ratio (INR) was noted after discharge till 3 months. All the patients were on acenocoumarol. Based on INR value, patients were categorized as Group A (effective anticoagulation INR within the therapeutic range or above) and Group B (ineffective anticoagulation INR > 50% below the therapeutic range). A repeat MRV at 3 months was done for recanalization. Outcome at 3 months was evaluated using modified Rankin Scale (mRS), and categorized as good (mRS ≤ 2) and poor (mRS 2 or more) 101(80.2%) patients were in group A and 25(19.8%) in group B. Their demographic, risk factors, magnetic resonance imaging (MRI) and MRV findings were comparable. On repeat MRV, recanalization occurred in 22/24(91.7%); 15(88%) in group A and 7(100%) in group B. Recanalization was independent of coagulation status. Seven (5.6%) patients died and 107(84.9%) had good outcome; 85(84.2%) in group A and 22(88%) in group B. Kaplan Meier analysis also did not reveal survival or good outcome benefits between the groups. In CVT, outcome and recanalization at 3 months are not dependent on coagulation status. Further prospective studies are needed regarding duration of anticoagulant and its impact on recanalization and outcome.     

Digital surface scanning in flap perfusion

Monitoring vascular perfusion of transferred tissue is essential in reconstructive surgery to recognize early flap failure. The aim of this study was to evaluate the ability of a digital surface scanner to detect vascular perfusion disorders through the monitoring of skin colour changes. A total of 160 surface scans of the forearm skin were performed with a TRIOS 3D scanner. Vascular compromise was simulated at different time-points by intermittent occlusion of the blood supply to the forearm skin (first the arterial blood supply and then the venous blood supply). Skin colour changes were examined according to the hue, saturation, and value colour scale. Colour differences were analysed with a paired t-test. Significant differences were observed between the colour of the normal skin and that of the vascular compromised skin (P < 0.01). The surface scanner could distinguish between arterial occlusion and venous congestion (P < 0.01). A digital surface scan is an objective, non-invasive tool to detect early vascular perfusion disorders of the skin.