Ultrasound therapy for treatment of lower extremity intermittent claudication.

Abstract

BACKGROUND\nWhile often thought of as a diagnostic tool, ultrasound (US) can also potentially be used as a therapeutic modality. US applies mechanical stress on endothelial cells and induces nitric oxide synthase, which regulates the secretion of nitric oxide, a potent vasodilator. In animal ischemic models, US has been shown to improve hindlimb, myocardial, and cerebral perfusion. We performed a pilot trial of US therapy in the lower extremities of human subjects with intermittent claudication.\n\n\nMETHODS\n10 subjects (5 male, 5 female, mean age 69.7\xa0±\xa010.3) with intermittent claudication were recruited. Both legs were placed in a specially designed boot with a water interface between US transducers and the legs. Subjects underwent pulsed US therapy at 250\xa0kHz frequency for 30\xa0min for three treatments a week for six weeks. Pre and post treatment ankle:brachial index (ABI), 6-min walk (6\xa0MW), Walking Impairment Questionnaire (WIQ), and Short Form 36 (SF36) were performed. Pre and post-treatment results were compared with paired t-test.\n\n\nRESULTS\nSix minute walking distance at baseline was 352\xa0±\xa070\xa0m, after one treatment session 353\xa0±\xa070\xa0m (p\xa0=\xa00.99), and at completion 372\xa0±\xa071\xa0m (p\xa0=\xa00.015). There was a trend toward improved ABI after 6 weeks of treatment (0.53\xa0±\xa00.17 vs 0.64\xa0±\xa00.12, p\xa0=\xa00.083). After six weeks, significant improvements were noted in overall WIQ score (2.00\xa0±\xa01.48 vs 2.63\xa0±\xa01.38, p\xa0=\xa00.0001), WIQ (distance) 2.07\xa0±\xa01.54 vs 2.73\xa0±\xa01.42 (p\xa0=\xa00.036), and WIQ (stair) 2.00\xa0±\xa01.67 vs 2.62\xa0±\xa01.24, p\xa0=\xa00.034, with a trend in WIQ (speed), 1.89\xa0±\xa01.26 vs 2.46\xa0±\xa01.43, p\xa0=\xa00.069. In the SF-36, significant improvements were noted in the domains of physical functioning (44.0\xa0±\xa041.6 vs 50.5\xa0±\xa041.1, p\xa0=\xa00.009) and role limitations - physical (35.0\xa0±\xa048.3 vs 60.0\xa0±\xa049.6, p\xa0=\xa00.006) after six weeks.\n\n\nCONCLUSIONS\nTherapeutic US is a potential noninvasive treatment for intermittent claudication. Pilot study patients noted significant improvements in 6\xa0MW and WIQ results after 6 weeks of treatment. A nonsignificant improvement in ABI was noted. Further research will be needed to clarify optimal treatment frequency and duration.