Clinical trial of percutaneous peripheral ultrasound angiopalsty

Siegel, Robert J.; Gaines, Peter A.; Crew, John R.; CumberlandM, David C.

doi:10.1016/0735-1097(93)90053-4

Cited by 39 publications

(16 citation statements)

References 28 publications

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“…A more recent report 27 showed a small acceleration of whole-blood clot lysis with urokinase in combination with 170-kHz ultrasound at 0.5 W/cm 2 . A catheter-mounted transducer at 225 kHz accelerated thrombolysis with urokinase in vitro, 20 as did a 20-kHz catheter-mounted transducer. 25 The latter demonstrated enhancement of fibrinolysis with 20-kHz ultrasound at intensities of 1 and 1.5 W/cm 2 and reported up to 40% "fibrinolysis" that may have represented mechanical clot disruption.…”

Section: Discussionmentioning

confidence: 99%

Enhancement of Fibrinolysis With 40-kHz Ultrasound

et al. 1998

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Background-Ultrasound at frequencies of 0.5 to 1 MHz and intensities of Ն0.5 W/cm 2 accelerates enzymatic fibrinolysis in vitro and in some animal models, but unacceptable tissue heating can occur, and limited penetration would restrict application to superficial vessels. Tissue heating is less and penetration better at lower frequencies, but little information is available regarding the effect of lower-frequency ultrasound on enzymatic fibrinolysis. We therefore examined the effect of 40-kHz ultrasound on fibrinolysis, tissue penetration, and heating. Methods and Results-125 I-fibrin-radiolabeled plasma clots in thin-walled tubes were overlaid with plasma containing tissue plasminogen activator (tPA) and exposed to ultrasound. Enzymatic fibrinolysis was measured as solubilization of radiolabel. Tissue attenuation and heating were examined in samples of porcine rib cage. Fibrinolysis was increased significantly in the presence of 40-kHz ultrasound at 0.25 W/cm 2 , reaching 39Ϯ7% and 93Ϯ11% at 60 minutes and 120 minutes, compared with 13Ϯ8% and 37Ϯ4% in the absence of ultrasound (PϽ0.0001). The acceleration of fibrinolysis increased at higher intensities. Attenuation of the ultrasound field was only 1.7Ϯ0.5 dB/cm through the intercostal space and 3.4Ϯ0.9 dB/cm through rib. Temperature increments in rib were Ͻ1°C/(W/cm 2 ). Conclusions-These findings indicate that 40-kHz ultrasound significantly accelerates enzymatic fibrinolysis at intensities of Ն0.25 W/cm 2 with excellent tissue penetration and minimal heating. Externally applied 40-kHz ultrasound at low intensities is a potentially useful therapeutic adjunct to enzymatic fibrinolysis with sufficient tissue penetration for both peripheral vascular and coronary applications.

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Section: Discussionmentioning

confidence: 99%

Enhancement of Fibrinolysis With 40-kHz Ultrasound

et al. 1998

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“…Previous reports have shown that US can accelerate fibrinolysis in vivo, but they differ from our findings in several respects. In some reports, thrombi were mechanically disrupted in vitro 22,23 or in animal models 23,24 with wires vibrating at US frequencies in the absence of plasminogen activator, and this approach has been tested in small studies in patients with coronary 25 or peripheral 26,27 arterial occlusion and with occluded coronary bypass grafts. 28 This treatment requires endovascular positioning of the wire, and it can result in vessel wall damage, excessive heating, and distal embolization of clot fragments.…”

Section: Suchkova Et Al Ultrasound Increases Thrombolysis and Perfusionmentioning

confidence: 99%

Effect of 40-kHz Ultrasound on Acute Thrombotic Ischemia in a Rabbit Femoral Artery Thrombosis Model

2000

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Background —We have shown previously that 40-kHz ultrasound (US) at low intensity accelerates fibrinolysis in vitro with little heating and good tissue penetration. These studies have now been extended to examine the effects of 40-kHz US on thrombolysis and tissue perfusion in a rabbit model. Methods and Results —Treatment was administered with either US alone at 0.75 W/cm 2 , streptokinase alone, or the combination of US and streptokinase. US or streptokinase resulted in minimal thrombolysis, but reperfusion was nearly complete with the combination after 120 minutes. US also reversed the ischemia in nonperfused muscle in the absence of arterial flow. Tissue perfusion decreased after thrombosis from 13.7±0.2 to 6.6±0.8 U and then declined further to 4.5±0.4 U after 240 minutes. US improved perfusion to 10.6±0.5 and 12.1±0.5 U after 30 and 60 minutes, respectively. This effect was reversible and declined to pretreatment values after US was discontinued. Similarly, tissue pH declined from normal to 7.05±0.02 after thrombosis, but US improved pH to 7.34±0.03 after 60 minutes. US-induced improvement in tissue perfusion and pH also occurred after femoral artery ligation, indicating that thrombolysis did not cause these effects. Conclusions —40-kHz US at low intensity markedly accelerates fibrinolysis and also improves tissue perfusion and reverses acidosis, effects that would be beneficial in treatment of acute thrombosis.

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“…The mechanical effect this form of ultrasound has on biological tissues was first noted by Conte and de Lorenzi (cited in Atar et al (27)) and its effectiveness is based on the fact that at the right combination of frequency and amplitude inelastic rigid tissue is vigorously disrupted while elastic tissue can absorb the energy (28,29).…”

Section: Iiia Backgroundmentioning

confidence: 99%

“…Siegel et al (29) experimentally tested a 19.5 kHz system on 50 lesions of which 34% were calcified. The results showed that ultrasound delivered via a wire waveguide could recanalise the arteries affected by the lesions and that the calcified arteries treated with therapeutic ultrasound could subsequently be dilated at lower pressures than before suggesting an overall increase in the distensibility of the lesion.…”

Section: Vc Prototypes and Clinical Devicesmentioning

confidence: 99%

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Ablation of Chronic Total Occlusions Using Kilohertz-Frequency Mechanical Vibrations in Minimally Invasive Angioplasty Procedures

McGuinness

Wylie²,

Gavin³

2010

Crit Rev Biomed Eng

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Certain minimally invasive cardiology procedures, such as balloon angioplasty and stent implantation, critically require that the site of an arterial blockage be crossed by an intraluminal guidewire. Plaques resulting in near or totally occluded arteries are known as chronic total occlusions (CTOs), and crossing them with conventional guidewires is a significant challenge.Among the most promising proposed solutions is the delivery of high power, low frequency ultrasonic vibrations to the occlusion site via an intraluminal wire waveguide. The vibrating distal-tip of the ultrasound wire waveguide is used to transmit energy to the surrounding plaques, tissues and fluids in order to ablate or weaken atherosclerotic plaque. Potential mechanisms of interaction with the plaque and adjacent fluids identified in the literature include; (i) direct contact with the waveguide distal tip, (ii) subcavitational acoustic fluid pressure fluctuations, (iii) cavitation, and (iv) acoustic streaming. This article will summarize developments in this area over more than two decades, describing experimental methods for device performance characterization, preclinical tests, early clinical investigations and, later, full clinical trials. The article will also review theoretical foundations, and numerical models suitable for device design and analysis. Finally, important issues for future research and for the development of this technology will be considered.

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Clinical trial of percutaneous peripheral ultrasound angiopalsty

Cited by 39 publications

References 28 publications

Enhancement of Fibrinolysis With 40-kHz Ultrasound

Enhancement of Fibrinolysis With 40-kHz Ultrasound

Effect of 40-kHz Ultrasound on Acute Thrombotic Ischemia in a Rabbit Femoral Artery Thrombosis Model

Ablation of Chronic Total Occlusions Using Kilohertz-Frequency Mechanical Vibrations in Minimally Invasive Angioplasty Procedures

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