INSERM U979, Institut Langevin, Paris, France. ESPCI Paris, PSL Research University, Institut Langevin, Paris, France. CNRS UMR 7587, Institut Langevin, Paris, France. Theraclion, Malakoff, France.
Phys Med Biol. 2019 Jan 7;64(2):025003. doi: 10.1088/1361-6560/aaf58d.
Venous insufficiency is a common disease arising when veins of the lower limb become incompetent. A conventional surgical strategy consists in stripping the incompetent veins. However, this treatment option is invasive and carries complication risks. In the present study, we propose noninvasive high-intensity focused ultrasound (HIFU) to treat lower limbs venous insufficiency, in particular incompetent perforating veins (mean diameter between 2-6 mm). Sonication parameters were designed by numerical simulations using the k-Wave toolbox to ensure continuous coagulation of a vein with a diameter superior or equal to 2 mm. The selected ultrasound exposures were 4 s pulses in continuous wave mode. Two types of sonication were studied: (1) fixed pulses and (2) moving pulses at constant speed (0.75 mm s) across the vein. The potential of these exposures to thermally occlude veins were investigated in vivo on rabbit saphenous veins. The impact of vein compression during ultrasonic exposure was also investigated. Fifteen rabbits were used in these trials. A total of 27 saphenous veins (mean diameter 2.0 ± 0.6 mm) were sonicated with a transducer operated at 3 MHz. After a mean 15 d follow-up, rabbits were euthanized and venous samples were extracted and sent for histologic assessment. Only samples with the vein within the HIFU lesion were considered for analysis. Simulated thermal damage distribution demonstrated that fixed pulses and moving pulses respectively placed every 1.5 and 0.5 mm along the vein and delivered at an acoustic power of 85 W and for 4 s were able to induce continuous thermal damages along the vein segments. Experimentally, both treatment parameters (1) and (2) have proven effective to occlude veins with a success rate of 82%. Occlusion was always observed when compression was applied. Our results demonstrate that HIFU can durably and non-invasively occlude veins of diameters comparable to human veins.
静脉功能不全是一种常见疾病，当下肢静脉变得功能不全时就会发生。一种传统的手术策略包括剥离功能不全的静脉。然而，这种治疗选择具有侵入性，并伴有并发症风险。在本研究中，我们提出了非侵入性高强度聚焦超声（HIFU）来治疗下肢静脉功能不全，特别是功能不全的穿静脉（直径在 2-6 毫米之间）。使用 k-Wave 工具箱进行数值模拟设计了超声参数，以确保直径大于或等于 2 毫米的静脉连续凝固。选择的超声暴露为连续波模式下的 4 秒脉冲。研究了两种类型的超声处理：（1）固定脉冲和（2）以 0.75 毫米/秒的恒定速度在静脉上移动的脉冲。在兔隐静脉上体内研究了这些暴露对热闭塞静脉的潜力。还研究了超声暴露期间静脉压缩的影响。这些试验共使用了 15 只兔子。使用 3 MHz 的换能器对总共 27 条隐静脉（平均直径 2.0 ± 0.6 毫米）进行了超声处理。平均 15 天后，处死兔子，提取静脉样本并进行组织学评估。仅对静脉位于 HIFU 病变内的样本进行分析。模拟的热损伤分布表明，分别放置在静脉上每 1.5 和 0.5 毫米处的固定脉冲和移动脉冲，在 85 W 的声功率下连续输送 4 秒，能够在静脉段上诱导连续的热损伤。实验中，两种治疗参数（1）和（2）都能有效地闭塞静脉，成功率为 82%。当施加压缩时，总是观察到闭塞。我们的结果表明，HIFU 可以持久地、非侵入性地闭塞与人静脉直径相当的静脉。
