Laser and radiofrequency endovenous ablation of venous reflux

Endovenous modalities to treat superficial venous reflux of the lower extremities have revolutionized management of patients with varicose veins. Laser and radiofrequency probes have both found their way into the arsenal of physicians treating venous reflux. Although both offer distinct advantages and minor drawbacks, they each offer the convenience of in-office treatment, faster recovery, and improved safety over traditional surgical procedures. This article will briefly discuss the technique, treatment results, and potential complications associated with each procedure.     

Update on endovenous laser ablation: 2011

In 2001, the use of endovenous laser ablation (EVLA) was introduced to the United States to treat superficial venous insufficiency. EVLA has subsequently undergone a rapid rise in popularity and usage with a concomitant decrease in traditional operative saphenectomy. Since its inception, the use of EVLA to treat superficial venous insufficiency has advanced significantly. The efficacy of treatment has been validated using both hemoglobin-specific laser wavelength and water-specific laser wavelength lasers. Currently, laser optimization is focusing on reducing postprocedural sequelae. The clinical parameters that correlate best with improved postoperative recovery use lower power/energy settings, water-specific laser wavelength lasers, and jacket or radial-emitting tips. Future study is still required to assess the durability of treatment at lower power and energy settings coupled with jacket or radial-emitting tip fibers. Long-term follow-up using duplex imaging is recommended to ensure persistent treatment success.     

大隐静脉主干射频消融治疗中的性别差异及彩色多普勒血管成像应用

目的探讨大隐静脉主干射频消融治疗中的性别差异及彩色多普勒血管成像（CDFI）应用体会。方法2018年3月1日~2019年6月1日武汉某三甲医院血管外科收治72例大隐静脉曲张患者,其中70例大隐静脉曲张（94条）患者进行围手术期CDFI评估,并局麻下实施进行大隐静脉主干射频消融治疗,分析大隐静脉射频消融治疗中CDFI的重要性及应用体会。结果72例就诊患者中70例顺利完成彩超引导下的大隐静脉射频消融,且术后均顺利出院,虽然未加行大隐静脉高位结扎,围手术期未发生深静脉血栓、肺栓塞等严重并发症;术后1月复查,大隐静脉主干均完全闭合。患者患肢不适症状（如水肿、疼痛、酸胀、沉重感、麻木等）均明显缓解或消失。男性/女性病人在年龄、手术部位、CEAP分级、大隐静脉主干返流时间、大隐静脉主干返流速度的差异均无统计学意义（P>0.05）;在大隐静脉主干内径比较上,男性/女性病人在左下肢的差异无统计学意义（P>0.05）,而在右下肢大隐静脉内径的差异存在统计学意义（P<0.05）。结论CDFI在大隐静脉曲张患者围手术期评估具有重要的作用,术前明确病变及手术方案选择、射频术中发挥引导作用,术后复查评估综合治疗效果。无高位结扎的大隐静脉射频消融术具有满意的短期效果,无严重并发症;女性病人右下肢大隐静脉内径明显小于男性病人右下肢大隐静脉内径。      

静脉腔内射频闭合治疗对犬血凝状态的影响

目的 观察静脉腔内射频闭合治疗对犬血凝状态的影响.方法 对健康成年杂种犬8只行后肢髂股静脉腔内射频闭合术.分别在插入血管鞘前、插入血管鞘后、射频闭合术后即刻及射频闭合术后30 min、12 h、24 h、48 h、72 h、1 W采集犬外周静脉血,用酶联免疫吸附法(ELISA)测定犬血浆血小板α-颗粒糖蛋白(GMP-140)、组织型纤溶酶原激活剂(t-PA)、组织型纤溶酶原激活剂抑制物-1(PAI-1)的浓度变化.结果 插入血管鞘后,GMP-140较插入血管鞘前升高(P<0.05),射频闭合术后即刻明显升高,且继续升高至射频术后48 h,术后1 W仍高于插入血管鞘前水平.t-PA及PAI-I在插入血管鞘前、后无明显变化(P>0.05).t-PA于射频闭合术后即刻达高峰,PAI-I于射频闭合术后30 min达高峰,均于射频闭合术后1 W恢复正常.结论 静脉腔内射频闭合术可激活血小板,使犬血液处于高凝状态,提示射频闭合术后有必要抗凝及抗血小板治疗以降低外周血管血栓形成的风险.     

Miniaturized ultrasound arrays for interstitial ablation and imaging

A potential alternative to extracorporeal, noninvasive HIFU therapy is minimally invasive intense ultrasound ablation that can be performed laparoscopically or percutaneously. An approach to minimally invasive ablation of soft tissue using miniaturized linear ultrasound arrays is presented here. Recently developed 32-element arrays with aperture 2.3 x 49 mm, therapy frequency 3.1 MHz, pulse-echo bandwidths >42% and surface acoustic energy density >80 W/cm2, are described. These arrays are integrated into a probe assembly, including a coupling balloon and piercing tip, suitable for interstitial ablation. An integrated electronic control system allows therapy planning and automated treatment guided by real-time interstitial B-scan imaging. Image quality, challenging because of limited probe dimensions and channel count, is aided by signal processing techniques that improve image definition and contrast, resulting in image quality comparable to typical transabdominal ultrasound imaging. Ablation results from ex vivo and in vivo experiments on mammalian liver tissue show that this approach is capable of ablation rates and volumes relevant to clinical applications of soft tissue ablation such as treatment of liver cancer.     

High-throughput multiphoton-induced three-dimensional ablation and imaging for biotissues

In this study, a temporal focusing-based high-throughput multiphoton-induced ablation system with axially-resolved widefield multiphoton excitation has been successfully applied to rapidly disrupt biotissues. Experimental results demonstrate that this technique features high efficiency for achieving large-area laser ablation without causing serious photothermal damage in non-ablated regions. Furthermore, the rate of tissue processing can reach around 1.6 × 10⁶ μm³/s in chicken tendon. Moreover, the temporal focusing-based multiphoton system can be efficiently utilized in optical imaging through iterating high-throughput multiphoton-induced ablation machining followed by widefield optical sectioning; hence, it has the potential to obtain molecular images for a whole bio-specimen.OCIS codes: (140.3390) Laser materials processing, (170.1020) Ablation of tissue, (190.4180) Multiphoton processes     

Laser ablation and the need for intra-arterial imaging

In 48 patients with severe claudication due to a total obstruction of the femoropopliteal artery, percutaneous recanalization was attempted with a 2.2 mm diameter rounded sapphire contact probe in conjunction with a continuous wave Nd:YAG laser. In eight patients the contact probe laser catheter took a subintimal course that could not be redressed. Laser recanalization needs high-resolution diagnostic information on the complex anatomy of the obstruction. Intra-arterial ultrasound imaging may provide the necessary information to evaluate, monitor or guide novel angioplasty techniques. The design of an ultrasound catheter which combines high-resolution diagnostic imaging with steerability, flexibility and controlled ablation is now the major engineering challenge in interventional cardiology.     

FEM-based elasticity reconstruction using ultrasound for imaging tissue ablation

Purpose

Success of ablation treatment depends on the accurate placement of the target ablation focus and the complete destruction of the pathological tissue. Thus, monitoring the formation, location, and size of the ablated lesion is essential. As ablated tissue gets stiffer, an option for ablation monitoring is ultrasound elastography, for imaging the tissue mechanical properties. Reconstruction of elasticity distribution can be achieved by solving an inverse problem from observed displacements, based on a deformable tissue model, commonly discretized by the finite element method (FEM). However, available reconstruction techniques are prone to noise and may achieve suboptimal accuracy.

Methods

We propose a novel inverse problem formulation and elasticity reconstruction method, in which both the elasticity parameters and the model displacements are estimated as independent parameters of an unconstrained optimization problem. Total variation regularization of spatial elasticity distribution is introduced in this formulation, providing robustness to noise.

Results

Our approach was compared to state of the art direct and iterative harmonic elastography techniques. We employed numerical simulation studies using various noise and inclusion contrasts, given multiple excitation frequencies. Compared to alternatives, our method leads to a decrease in RMSE of up to 50% and an increase in CNR of up to 11 dB in numerical simulations. The methods were also compared on an ex vivo bovine liver sample that was locally subjected to ablation, for which improved lesion delineation was obtained with our proposed method. Our method takes \(\sim 4\,\hbox {s}\) for \(20\times 20\) reconstruction grid.

Conclusions

We present a novel FEM problem formulation that improves reconstruction accuracy and inclusion delineation compared to currently available techniques.

     

腔内射频闭合治疗下肢静脉曲张

目的评价下肢大隐静脉曲张射频闭合治疗的临床疗效。方法20例(23条下肢)大隐静脉曲张接受射频消融闭合治疗,选用合适的射频导管(6F或8F)在超声引导下插入大隐静脉至隐股静脉交界下方0.5 cm处,保持85℃的情况闭合大隐静脉。结果射频闭合治疗患者20例,23条肢体,射频闭合时间30~40 min,患者平均术后住院日5 d,无一例术后皮下淤血、皮肤灼伤或小腿麻木(隐神经损伤),术后症状缓解,3例踝部轻度肿胀,适当抬高患肢、理疗处理2个月后消退;2例足靴区溃疡,术后5周愈合;术后随访12~30月,术后1个月、4个月、8个月、12个月定期超声检查,所有患者大隐静脉主干均闭合良好,无复发临床表现,深静脉通畅,无血栓形成。结论大隐静脉射频闭合术具有创伤小、并发症少、恢复快等优点,是治疗下肢大隐静脉曲张值得选择的方法之一。     

Minimally invasive vein therapy and treatment options for endovenous heat-induced thrombus

Radiofrequency ablation and endovenous laser therapy are types of minimally invasive techniques that have been used in the treatment of chronic venous insufficiency. In both procedures, high-intensity heat via thermal energy is produced and delivered via an endovenous catheter placed in the saphenous vein. This results in changes that therapeutically induce closure of the vein by denaturing the vessel wall with subsequent thrombus formation. Patients undergo ultrasound 48 to 72 hours postprocedure to confirm vessel occlusion and assess for possible extension of thrombus into the deep venous system. Thrombus is frequently visualized with the procedure in the tributaries, the venous dilations, and at times the saphenofemoral junction. In any other setting, thrombus at the saphenofemoral junction would warrant anticoagulation. However, the characteristics, composition, and behavior of endovenous heat-induced thrombus are different than de novo thrombosis. This postprocedure endovenous heat-induced thrombus is considered a normal consequence of the procedure and does not require traditional anticoagulation in most cases, depending on the location.     

大隐静脉高位结扎联合腔内微波治疗下肢静脉曲张的效果

目的探讨大隐静脉高位结扎联合腔内微波(EMA)治疗下肢静脉曲张的临床效果。方法选取2017年1月至2018年6月在我院住院的140例单纯下肢静脉曲张患者,按不同治疗方法将其分为对照组(70例,128条肢体,行大隐静脉高位结扎加剥脱术)与观察组(70例,130条肢体,行大隐静脉高位结扎联合EMA)。比较两组患者的手术指标、疼痛、术后并发症发生情况及术前、术后1年的静脉曲张程度。结果观察组手术时间、抗生素使用时间及住院时间短于对照组(P<0.05)。观察组患者的疼痛程度优于对照组,并发症总发生率低于对照组(P<0.05)。术后1年,两组患者的VCSS评分均降低,且观察组低于对照组(P<0.05)。结论大隐静脉高位结扎联合EMA治疗下肢静脉曲张的效果理想,操作简单,创伤小,可缓解静脉曲张程度,值得临床推广。     

磁共振成像在房颤导管射频消融术中的应用

导管射频消融术是公认的症状性、药物难治性房颤的首选治疗方法。术前对肺静脉及左房解剖情况的准确评估至关重要,但却受限于传统的影像学方法。随着无创影像三维重建技术的日趋完善,尤其是核磁共振成像(MRI)技术,使得术前评估肺静脉及左房纤维化情况已成为现实。此外,MRI还可对术后左房损伤及瘢痕组织情况作出准确评估,可用于预测房颤的预后,亦可用于确定二次消融位点,达到彻底电隔离肺静脉。     

Reflux Nephropathy and Primary Vesicoureteric Reflux in Adults

We have studied the clinical features and course of adults withreflex nephropathy and/or primary vesicoureteric reflux, payingparticular attention to the differences between males and females,and the presenting features that influence prognosis. In ourseries of 293 patients, females outnumbered males in the ratio5:1 and most presented with urinary infection, whereas malesmost commonly presented with features of renal damage such asproteinuria, hypertension or renal failure. Males more commonlyhad bilateral scarring and persistent reflux. One hundred and forty-seven patients were followed for two yearsor more (range 2–19 years); deterioration in renal functionoccurred in 55 (37 per cent). Risk factors for a rise in plasmacreatinine were, in descending order, the presence of proteinuria,an elevated plasma creatinine concentration, bilateral scarring,male sex and the presence of hypertension. Stepwise multipleregression analysis showed that the independent risk factorswere proteinuria, elevated plasma creatinine concentration andhypertension; gender and the presence of persistent reflux hadno independent influence on the course of renal failure.     

抗返流疗法治疗声嘶的系统评价

目的通过全面检索前瞻性随机对照研究,系统评价在无其它明显病因时,抗返流疗法(药物或手术均可)治疗声嘶患者的疗效(无论是否确诊咽喉返流或胃食管返流)。方法用事先确定的关键词检索Cochrane ENT组临床试验注册库、Cochrane临床对照试验中心注册库(CENTRAL) (Cochrane图书馆2005年第3期)、MEDLINE(1966-2005)、EMBASE(1974-2005)及会议论文集。检索时间更新至 2005年9月。研究对象为无其它明显病因(如恶性肿瘤、声带麻痹或结节),无论是否确诊咽喉返流或胃食管返流的声嘶患者的随机对照试验。由三名评价者浏览检索结果,筛选试验,以决定是否纳入本系统评价。结果共检索到302项试验,但均不符合本评价纳入标准。其中有6项随机对照试验,报告其部分研究对象有声嘶症状,采用了质子泵抑制剂治疗。但我们无法确定其他研究对象的喉部症状是否包括声嘶,因此排除这些试验。但这些试验显示安慰剂也有明显效果,在某些试验中与抗返流疗法疗效相当。由于没有符合纳入标准的试验,对抗返流疗法治疗声嘶的疗效我们无法得出明确结论。结论尚需高质量随机对照试验评价抗返流疗法对可能因咽喉返流或胃食管返流所致的声嘶的疗效。     

High-frequency ultrasound m-mode imaging for identifying lesion and bubble activity during high-intensity focused ultrasound ablation

Effective real-time monitoring of high-intensity focused ultrasound (HIFU) ablation is important for application of HIFU technology in interventional electrophysiology. This study investigated rapid, high-frequency M-mode ultrasound imaging for monitoring spatiotemporal changes during HIFU application. HIFU (4.33 MHz, 1 kHz PRF, 50% duty cycle, 1 s, 2600?6100 W/cm²) was applied to ex vivo porcine cardiac tissue specimens with a confocally and perpendicularly aligned high-frequency imaging system (Visualsonics Vevo 770, 55 MHz center frequency). Radio-frequency (RF) data from M-mode imaging (1 kHz PRF, 2 s × 7 mm) was acquired before, during and after HIFU treatment (n = 12). Among several strategies, the temporal maximum integrated backscatter with a threshold of +12 dB change showed the best results for identifying final lesion width (receiver-operating characteristic curve area 0.91 ± 0.04, accuracy 85 ± 8%, compared with macroscopic images of lesions). A criterion based on a line-to-line decorrelation coefficient is proposed for identification of transient gas bodies.