A practical approach to tumescent local anaesthesia in ambulatory endovenous thermal ablation.

BACKGROUND: Thermal ablation, usually performed with tumescent local anaesthesia (TLA), is the preferred method for varicose veins treatment. Tumescent local anaesthesia is always cited; however, little detail of the procedure is presented in publications. This retrospective audit of clinical tumescent local anaesthesia practice aims to provide detailed information on an important aspect of endovenous practice. METHODS: Patients who underwent three types of endothermal treatment (Venefit, Radiofrequency Induce Thermal Therapy and Endovenous Laser Ablation) to a single saphenous trunk using tumescent local anaesthesia were assessed. Differences in tumescent local anaesthesia volume per unit length of treated vein were assessed for the followings: type of saphenous trunk, length of vein treated, effect of additional phlebectomy and bilateral versus interval unilateral treatment for bilateral veins. Descriptive data are reported as mean and standard deviation, and groups were compared using the one-way ANOVA test. RESULTS: Between 2008 and 2014, single-saphenous-trunk ambulatory TLA thermal ablation was performed in 979 patients, mean age was 54 years. A total of 1229 limbs had truncal ablations and synchronous phlebectomy was performed in 470 limbs. No tumescent local anaesthesia-related complications occurred. There was no significant difference in standardised tumescent local anaesthesia volume per centimetre (ml) used for the three devices. Tumescent local anaesthesia volume per centimetre (ml) differed significantly between saphenous trunks. On average, a standard 10-12 ml/cm of tumescent local anaesthesia was used for saphenous trunks. Mean total tumescent local anaesthesia volume per patient, when treating the great saphenous vein alone, was 931 ml for bilateral and 425 ml for unilateral treatment. CONCLUSION: This report of over 1000 endovenous procedures demonstrates safe performance of laser and radiofrequency treatments using tumescent local anaesthesia. Although no attempt was made to determine minimum volume requirements, a mean tumescent local anaesthesia volume of 10-12 ml/cm administered to the perivenous space provides adequate anaesthesia for truncal saphenous ablation.

[EFFICACY OF SURGICAL TREATMENT OF VARICOSE DISEASE, DEPENDING ON ADSORPTION-RHEOLOGIC PROPERTIES OF BLOOD].

Physico-chemical adsorption-rheological properties of venous blood in patients, suffering varicose disease of the lower extremities, and their impact on efficacy of various methods of surgical treatment were studied. Conduction of endovasal laser coagulation in combination with crossectomy have promoted enhancement of operative treatment efficacy in patients in initial terms of observation (in 1 week), in 1 month a complete occlusion of the vein was noted more rarely. Efficacy of a small--power laser ablation with irradiation power of 10 W and less in 4 weeks postoperatively is higher, than of surgical treatment with a laser irradiation power 15 W. In a varicose disease of the lower extremities there were observed the raising of the blood volume toughness, superficial relaxation and superficial stress on background of reduction of the toughness--elasticity module, superficial toughness and superficial elasticity. Crossectomy conduction did not influence the integral dynamics of adsorption--rheological properties of venous blood, but in 1 month after endovasal laser coagulation a normalization of physicchemical parameters of blood was noted. Application of laser irradiation of the 10 W power and less promotes inhibition of the relaxation properties of venous blood; a prognostic meaning owes initial value of the blood volume toughness.

Changing to endovenous treatment for varicose veins: how much more evidence is needed?

Surgical ligation and stripping of varicose veins has been the accepted treatment for almost a century but within the last decade this has been challenged by endovenous thermal and chemical ablation methods. Surgery is not without significant complications including paraesthesia and has reflux recurrence rates of up to 54% at five years, even though it has been shown to provide significant health-related quality of life benefits cost-effectively. Ultrasound-guided foam sclerotherapy, endovenous laser ablation and radiofrequency ablation are all consistently proving to be at least as beneficial as surgery, without the same complications and with less post-procedure morbidity and more rapid recovery. This article presents a review of the latest published evidence and comparative analysis of vein surgery and it's alternatives. Endovenous treatment under local anaesthesia in a clinic room or office-based setting is now being recognized internationally as an acceptable standard for dedicated venous practice in a cost-effective environment. Although more long-term comparative trials of these innovative methods compared with surgery are desirable, many centres are now conducting trials testing the latest endovenous device technologies with each other to support the development of contemporary pathways of care. Patients are entitled to a range of treatment strategies, particularly when complex and recurrent venous disease has such unacceptably high surgical complication and recurrence rates compared to endovenous alternatives. There is questionable logic in procrastinating until there is more convincing evidence. Now is the time for vascular surgeons to enhance their ultrasound skills and future-proof their venous practice for the benefits of patients and institutions.

Long-term results following percutaneous myocardial laser therapy.

OBJECTIVES: The usefulness and safety of percutaneous myocardial laser therapy in selected patients have been identified in previous 1-year randomized trial reports, including that from a double-blind, sham-controlled trial we independently conducted. We aimed to determine whether the 1-year effects are maintained through a long-term, longitudinal follow-up. METHODS: Patients (n=77) with chronic, stable, medically refractory angina (class III or IV) not amenable to conventional revascularization and with evidence of reversible ischemia, ejection fraction > or =25%, and myocardial wall thickness > or =8 mm were treated with percutaneous myocardial laser. After the 1-year follow-up and disclosure of all randomized assignments as prespecified in the respective study protocol, patients were followed up longitudinally for a mean of 3 years for angina class, left ventricular ejection fraction, medication usage, and adverse events. RESULTS: No procedural mortality, myocardial infarction, or cerebral embolism occurred. Pericardiocentesis was required in two patients (2.6%). Cardiac event-free survival was 88% at 1 year and 66% at late follow-up. Mean Canadian Cardiovascular Society angina class was significantly improved from baseline (3.2+/-0.4) at 1 year (2.2+/-1.1, P<0.001) and at a mean of 3 years (1.9+/-1.2, P<0.001). Nitrate usage was significantly reduced at late follow-up; however, ejection fraction did not change over time. In a multivariate analysis, angina improvement at 1 year was found to be a significant independent predictor of both survival and angina improvement at late follow-up. CONCLUSION: We conclude that percutaneous myocardial laser therapy in selected patients with severe, medically refractory angina not treatable with conventional revascularization induces significant and sustained symptomatic benefit.

Endovascular excimer laser atherectomy techniques to treat complex peripheral vascular disease: an orderly process.

Peripheral vascular disease represents the largest obstructive subsegment within the vascular system. Advances in equipment, techniques, biochemical treatments, and the influx of multiple specialties into this arena indicate a coming tidal wave of change to the standard treatment plan for patients with claudication and especially critical limb ischemia. Initial attempts in the 1980s to utilize the "laser" to treat peripheral vascular disease led to a clinical debacle: wavelengths and methods were not optimized; tissue heating was excessive, resulting in restenosis. Since then the "laser" has fallen from grace for endovascular treatment, although it has an infinite set of potential wavelengths, energy levels, and delivery methods. The xenon chloride, excimer laser, a pulsed 308-nm system, has overcome many of these early catastrophes. The long, ongoing success of this method of photoablating thrombus and plaque represents a true step forward in the endovascular treatment of occlusive disease. Although only a tool, the excimer laser provides a means to utilize electromagnetic energy instead of shearing mechanical force to resolve occlusions. With its active element at the tip, the excimer laser requires much less mechanical translation force to cross total occlusions, find the distal lumen, and thereby cause less plaque destabilization. In addition, removing the firm surface layer of plaque, decapping, and some of the plaque volume, debulking, exposes the softer subsegments of the plaque to balloon angioplasty. Utilizing this method, more complex lesions can be approached safely, with a high likelihood of successful revascularization and a low risk of potentially limb-threatening complication.

Alternative therapeutic strategies for patients with severe end-stage coronary artery disease not amenable to conventional revascularization.

Although there have been remarkable advances in medical therapy, percutaneous coronary interventions, and coronary artery bypass graft surgery, complete revascularization remains a challenge given the more complex coronary artery disease prevalent in contemporary practice. The lack of donors for cardiac transplantation will fuel the search for effective alternative strategies for dealing with patients with severe ischemic heart disease not amenable to conventional revascularization techniques. Percutaneous laser revascularization clearly diminishes anginal symptoms; however, the blinded trials have provided conflicting results, with one study showing a definite decrease in angina and another suggesting that the placebo effect may play a major role in this modality. Similarly, surgical transmyocardial laser revascularization is limited by the lack of consistent improvement in objective measurements of ischemia and the potential confounding mechanisms of denervation and the placebo effect, and thus should be reserved for only the most highly selected patients. Although enhanced external counterpulsation is associated with an improvement in anginal symptoms and exercise tolerance, this modality is limited by its availability, tolerability, and rigid exclusion criteria. Of the alternative strategies available, therapeutic angiogenesis holds the most promise. However, the long-term results of ongoing randomized clinical trials require further scrutiny. Novel methods for vascular reconstruction are evolving techniques, but should be viewed currently as mainly experimental methods. The common goals of these new treatment options would be to reduce symptoms, decrease morbidity, and potentially improve mortality by reducing ischemia through favorably impacting myocardial oxygen supply and demand. The optimal management of patients with severe end-stage coronary artery disease not amenable to conventional revascularization techniques will continue to remain a challenge for the clinician and will be the main focus of basic cardiovascular research and clinical trials in the new millennium.

Vascular procedures that thermo-coagulate collagen reduce local platelet deposition and thrombus formation: laser and laser-thermal versus balloon angioplasty.

BACKGROUND AND OBJECTIVE: Exposure of the arterial wall matrix to blood leads to platelet deposition resulting in thrombosis. Because heat alters tissue matrix we proposed that heating reduces platelet deposition. STUDY DESIGN/MATERIALS AND METHODS: Sixty arterial homografts (15 dogs) were mounted in an arterio-venous "shunt." Interventions included balloon angioplasty (BA), direct laser (LA), laser-thermal (LTA), and combined LTABA. 111Indium-labeled platelets were circulated, radio activity measured, and homografts processed for histology. RESULTS: Radioactivity count (mean+/- SE) at BA sites (13,853+/-3,192 cpm/cm(2)) was greater than LA (7,038+/-981), LTA (5,294 +/-1,145), LTABA (6,176+/-1,571), and control (1,826+/-339), P<0.05. Electron microscopy showed fewer platelets at LA, LTA, and control than BA sites. BA spread the collagen on the arterial lumen while heat gelled collagen and confined it to the arterial media. CONCLUSIONS: Heating the artery and gelling collagen during LA, LTA, or LTABA significantly reduced thrombogenicity.

Saline flush during excimer laser angioplasty: short and long term effects in the rabbit femoral artery.

BACKGROUND AND OBJECTIVE: In this study, the effect of flushing saline on arterial wall damage (medial ruptures and necrosis), intimal hyperplasia, and arterial remodeling was determined. During excimer laser coronary angioplasty saline is flushed to reduce the size of explosive water vapor bubbles formed by intraluminal delivery of excimer laser pulses in blood. METHODS: In the femoral artery of the rabbit, 600 excimer laser pulses (308 nm, 50 mJ/mm2 per pulse, 20 Hz) were delivered coaxially over a length of 20 mm in 10 bursts of 3 seconds each. In 24/48 procedures, saline was flushed (0.2 ml/s) via the guidewire channel. After 2 and 56 days, microscopic and angiographic results were compared. RESULTS: At 2 days, as compared to lasing in blood, saline flush had drastically reduced the incidence of dissections (2/12 vs. 11/12, P < 0.002), but had increased the extent of medial and adventitial necrosis. The latter is attributed to direct irradiation of the arterial wall. After 56 days, in the saline group, in the middle-distal part of treated segments, medial necrosis without intimal hyperplasia was observed. However, at the edges of these lesions, intimal hyperplasia and arterial shrinkage reduced the lumen. CONCLUSION: Flushing saline during coaxial excimer laser pulse delivery significantly reduced the incidence of vessel wall ruptures, and prevented intimal hyperplasia formation in part of the lesion. The histologic findings at 56 days are attributed to the optical window which the saline flush provides for direct ultraviolet light irradiation of the arterial wall.

Influence of carbon dioxide gas perfusion to thermal distribution of sapphire probe. A comparative study with saline.

RATIONALE AND OBJECTIVES: A previous study confirmed that the direct laser-thermal conduction of the sapphire probe with carbon dioxide gas perfusion increased the width of the laser-recanalized channel. This caused us to further investigate the thermal distribution characteristics of the sapphire probe when lasing with CO2 gas perfusion. METHODS: The surface temperature of a sapphire probe in a circulation model using 37 degrees C flowing whole blood was measured. Two hundred and sixteen measurements were obtained by directly contacting a flexible thermocouple wire onto the sapphire probe at different sites: 1) metal connector; 2) lateral side of the sapphire crystal; 3) top of the sapphire crystal; and 4) 3 mm in front of the sapphire probe. During lasing with a neodymium-yttrium-aluminum garnet (Nd-YAG) laser, the CO2 gas or saline was infused through the sapphire probe at different flow rates. RESULTS: The lateral side of the sapphire crystal was heated up to 75 degrees C when lasing without any perfusion, but up to 220 degrees C when lasing with CO2 gas perfusion. At all four sites, the mean temperature increases were statistically higher (P < .01) with CO2 gas than with saline perfusion. The mean peak temperatures increased with increasing flows of CO2 gas perfusion and decreased with increasing flows of saline perfusion. CONCLUSIONS: The thermal conduction from the sapphire probe can be significantly enhanced by increasing flows of CO2 gas perfusion. This may play an important role in creating a greater diameter of the recanalized channel and in better delaying the formation of restenosis or re-occlusion after laser recanalization of atheromatous arteries.

Loss of vasoreactivity by laser thermal energy or argon laser irradiation.

Vasoreactivity of laser-treated vessels was investigated in two different experimental conditions. The canine left circumflex coronary artery (LCx) was lased under perfusion with Krebs-bicarbonate buffer by means of a thermal laser (hot-tip probe, HT) at 7 W for 6 seconds and an argon laser beam through a 300 microns optical fiber at 3 W (tip power) for 1 second at 12 spots. A nontreated segment of the LCx served as a control. Two 3-mm long segments were obtained from the treated segment: one to measure the results of potassium (K) induced contraction, and another 3, 4 diaminopyridine (DAP; K channel inhibitor) induced contraction. In 11 instances, coronary angiography of the perfused artery showed less than 50% stenosis after laser treatment. The segments were then mounted isometrically with 1 g tension in Krebs-bicarbonate buffer. Contraction was induced either with 30 mM KCI or 10(-2) M DAP and expressed as developed tension (gram; g). KCI induced vasocontraction of 4.15 +/- 0.93 g in the control, 0.33 +/- 0.71 g in laser irradiated segments (P < 0.0001 vs control), and 0.02 +/- 0.06 g in thermally-treated segments (P < 0.0001 vs control). DAP induced vasocontraction of 5.21 +/- 1.32 g in the control, 0.39 +/- 0.83 g in laser irradiated segments (P < 0.0001 vs control), and 0.07 +/- 0.13 g in thermally treated segments (P < 0.001 vs control). In 4 instances, more than 50% stenosis remained and additional balloon dilatation reduced the stenosis to less than 50%. The lesions also showed reduced vasoreactivity. In vivo thermal angioplasty resulted in reduced vasoreactivity compared to control in 4 anesthetized dogs. Thus, laser and thermal angioplasty reduced vasoreactivity induced by either KCI or 3, 4 DAP. Neither acetylcholine at 10(-6) M nor papaverine at 10(-4) M was able to induce relaxation of treated segments. In conclusion, 1) the lased coronary artery loses its vasoreactivity to either a constrictive or relaxing agent, 2) although stenosis may be produced by laser energy, additional balloon dilatation can reduce residual stenosis, and 3) laser thermal or argon laser angioplasty may prevent severe coronary spasm.

XeCl laser ablation of atherosclerotic aorta: luminescence spectroscopy of ablation products.

XeCl laser ablation of atherosclerotic aorta tissue was investigated. Luminescence spectra of ablation products were measured for soft and hard arterial tissues. A pronounced difference observed between plume luminescence for various plaques and normal vessel wall correlates with the chemical composition of the tissue. The mechanism of plume luminescence appeared to be thermochemical excitation ablation products (particles, atoms, molecules, etc.) in the air. The process of soft tissue ablation was delayed with respect to the exciting laser pulse at relatively low laser fluences close to the ablation threshold. The kinetics of the ablation process as a function of laser-pulse energy fluence is reported. The data indicate that tissue ejection mechanism, which involves vapor bubbles formation, expansion and explosion, is suitable for the description of the XeCl excimer laser ablation of soft tissues.

Thermal laser arterial injury and prostacyclin administration in dogs: thrombotic and hyperplastic consequences.

Angioplasty is considered as an alternative to surgical reconstruction of arteriosclerotic vessels especially since lasers and atherectomy devices have become clinically available. However, the resulting arterial injury may lead to acute thrombotic occlusion and chronic restenosis because of hyperplastic vascular repair. The purpose of this experimental study was to evaluate the consequences of thermal laser arterial injury on platelet deposition and myointimal hyperplasia in dog femoral arteries. An intraarterial, short-term prostacyclin (PGI2) infusion was given to evaluate the antithrombotic and antiproliferative effects of this drug. Severe arterial necrosis, partly carbonized and vacuolized, extending to the adventitia was induced by a transluminal heated laser probe motion. The platelet deposition after one hour was 33.62 +/- 6.56 (x 10(6)/cm2.) (mean +/- SEM) without prostacyclin, after 40 ng/kg/min prostacyclin (PGI2) 24.70 +/- 5.45 and after 400 ng/kg/min 9.3 +/- 2.26 (p less than 0.005 no PGI2 vs 400 ng/kg/min PGI2). Myointimal hyperplasia was present eight weeks after thermal laser vascular injury independent of the initially administered prostacyclin. In conclusion, acutely thrombotic and chronically hyperplastic femoral arteries were found following transluminal thermal arterial injury in dogs. Prostacyclin administration could be clinically beneficial in reducing acute vascular thrombosis following thermal angioplasty. Short-term use of this substance, however, may not prevent a hyperplastic response to angioplasty.

Atherosclerotic rabbit iliac arteries: comparison of balloon angioplasty and laser-assisted balloon angioplasty.

The effects of balloon angioplasty (BA) and laser-assisted balloon angioplasty (LABA) on arteries were compared. Atherosclerosis was induced in the iliac arteries of New Zealand White rabbits by means of balloon denudation and a diet supplemented with 1% cholesterol and 3% peanut oil. Six weeks later, one iliac artery was dilated with a 2.5- or 3.0-mm-diameter balloon. The contralateral iliac artery was treated with a 1.5-mm-diameter laser probe heated with 6 W of argon laser energy, and then BA was performed. Four weeks later, the mean luminal diameter of the LABA-treated arteries was smaller than that of the BA-treated arteries (BA, 1.57 mm +/- 0.15; LABA, 0.82 mm +/- 0.19; P less than .01). This restenosis was due to greater intimal fibrocellular proliferation (intimal area: BA, 0.83 mm2 +/- 0.16; LABA, 1.41 mm2 +/- 0.26; P less than .05). The LABA-treated arteries produced less potassium chloride-induced maximal force (P less than .01) and had smaller incremental elastic moduli (P less than .05) than did the BA-treated arteries. LABA is not the treatment of choice for small-caliber arteries, in which thermal injury to the arterial wall would be significant.