Ultrasound-Assisted Versus Conventional Catheter-Directed Thrombolysis for Acute Iliofemoral Deep Vein Thrombosis

High-Pressure Low-Frequency Lateral Mode Phased-Array Transducer System for the Treatment of Deep Vein Thrombosis: An In Vitro Study

Deep vein thrombosis (DVT) can lead to a fatal disease known as pulmonary embolism. Application of high-power ultrasound has been successful in studies to mechanically fragment the clots. Single-element ultrasound transducers were used in most of the studies. Challenges associated with phased arrays, such as high electrical impedance and element breakdown at high voltages, were addressed in the previous study, and a high-power 64-element transducer module was designed and fabricated. In this study, a cylindrical array of 16 modules with the frequency of 260 kHz was modeled and constructed for DVT thrombolysis. The maximum pressure, focal size, and steering ability of the array were examined. In vitro experiments were conducted to assess the performance of the array. The simulated pressure amplitude of 34 MPa at the depth of 55 mm (average femoral vein (FV) distance from the inner surface of the thigh) was in consistent with the experiments and satisfied the purpose of this study. Moreover, the employed module distribution resulted in a focal spot dimension of 2.4×2.8×7.3 mm³ (at the 75% pressure amplitude level) that can be confined in a human FV with the average diameter of 12 mm. In vitro experiments manifested a partial and complete clot breakdown at 11.5- and 15-MPa pressure at the focus. The design and engineering of the array system was succeeded in maintaining the desired pressure and focal size even when steered. The results presented in this study suggest the potential of the designed array system for clinical applications.

A systematic review on the use of deep venous stenting for acute venous thrombosis of the lower limb

OBJECTIVES

The aim is to evaluate venous stent patency, the development of post-thrombotic syndrome, recurrence, quality of life and the optimal post-procedural anticoagulation regimen in the treatment of iliofemoral deep venous thrombosis.

METHOD AND RESULTS

EMBASE and Medline databases were interrogated to identify studies in which acute deep venous thrombosis patients were stented. Twenty-seven studies and 542 patients were identified. Primary, assisted primary and secondary patency rates 12 months after stent placement ranged from 74 to 95, 90 to 95 and 84 to 100%, respectively. The observed post-thrombotic syndrome rate was 14.6%. The incidence of stent re-thrombosis was 8%. In 26% of studies, patients received additional antiplatelet therapy. Quality of life questionnaires employed in 11% of studies, demonstrating an improvement in the chronic venous insufficiency questionnaire (22.67 ± 3.01 versus 39.34 ± 6.66).

CONCLUSION

Venous stenting appears to be an effective adjunct to early thrombus removal; however, further studies are needed to identify optimal anticoagulant regimen and effect on quality of life.