Shock waves in vascular diseases: an in-vitro study

Cardiovascular applications of therapeutic ultrasound

Ultrasound (US) has gained widespread use in diagnostic cardiovascular applications. At amplitudes and frequencies typical of diagnostic use, its biomechanical effects on tissue are largely negligible. However, these parameters can be altered to harness US's thermal and non-thermal effects for therapeutic indications. High-intensity focused ultrasound (HIFU) and extracorporeal shock wave therapy (ECWT) are two therapeutic US modalities which have been investigated for treating cardiac arrhythmias and ischemic heart disease, respectively. Here, we review the biomechanical effects of HIFU and ECWT, their potential therapeutic mechanisms, and pre-clinical and clinical studies demonstrating their efficacy and safety limitations. Furthermore, we discuss other potential clinical applications of therapeutic US and areas in which future research is needed.

Shockwave therapy in patients with peripheral artery disease

INTRODUCTION

Previous studies support the fact that extracorporeal shockwave (SW) induces angiogenesis and improves symptoms in patients affected by limb ischemia. The aim of this study was to evaluate the effects of SW therapy in patients with peripheral artery disease (PAD).

METHODS

Twenty-two patients were enrolled in this study and were randomly assigned into two groups: SW treatment (12 patients, 67 ± 9 years) and control (10 patients, 68 ± 12 years). The inclusion criteria were the following: age over 40 years, PAD diagnosis, optimal medical therapy, and ankle-brachial index less than 0.9. SW therapy was administered using the Minilith® SL1 litotriptor with an ultrasound guide able to detect the target area using a B-mode technique and a 7.5 MHz convex probe emitting 2,000 impulses with an energy flux density of 0.03 mJ/mm(2).

RESULTS

The variation in the degree of stenosis before and after treatment was statistically significant between the groups (-9% ± -10% vs. 0% ± 0%; P = 0.001). In addition, a significantly higher number of treated patients than controls showed a reduction in the Fontaine stage (12 [63%] vs. 0 [0%]; P < 0.001). This result was confirmed by analyzing the difference in patients' pain-free walking distance before and after SW therapy (76 ± 46 m vs. 0 ± 0 m for treated patients vs. controls; P < 0.001) and the difference in pain severity (measured on a pain scale; -1.4 ± 0.5 in the treated patients vs. -0.2 ± 0.4 in the controls; P < 0.001).

CONCLUSION

On the basis of these results the authors hypothesized a direct effect of SW on the ultrastructural composition of the vessel walls, inducing a reduction in artery stenosis. These data support the application of SW therapy as a new medical tool to improve the natural clinical course of PAD.

Métodos físicos utilizados para oclusão de varizes dos membros inferiores

A terapia das varizes dos membros inferiores tem sido realizada classicamente por cirurgia e escleroterapia, sendo a escolha basicamente dependente do seu calibre. Entretanto, a associação de técnicas costuma ser uma necessidade para a obtenção de bons resultados. Os meios físicos surgiram no final da década de 50 e continuaram a progredir com grande diversidade quanto à natureza, princípio físico e efeitos. A complexidade tecnológica é bastante variável. Eletrocoagulação, laser, luz intensa pulsada, crioesclerose endovascular, ultra-som e microondas são meios físicos potencialmente viáveis para esta condição. Entretanto, com algumas exceções, pouco tem sido descrito fora dos centros de pesquisa, e a participação como opção terapêutica ainda necessita de uma melhor definição do papel. O artigo tem como objetivo descrever os métodos físicos empregados ou em estudo para a terapia de varizes.