In-vitro assessment of the thrombolytic efficacy of therapeutic ultrasound

• Published in: Thrombosis research Vol. 178; pp. 63 - 68
• Main Authors: Salman-Kesner, Nava, Zaltsman, Masha-Maria, Ertracht, Offir, Atar, Shaul
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.06.2019
• Subjects: Fibrinolytic Agents - pharmacology; Fibrinolytic Agents - therapeutic use; Humans; Therapeutic ultrasound; Thrombolysis; Thrombolytic Therapy - methods; Thrombosis; Ultrasonic Therapy - methods; Ultrasound; Therapeutic ultrasound; Ultrasound; Thrombosis; Thrombolysis
• ISSN: 0049-3848; 1879-2472
• DOI: 10.1016/j.thromres.2019.04.002

Ultrasound is mainly used as a diagnostic tool. Several studies demonstrated that therapeutic ultrasound (TUS) can enhance thrombolysis, but the optimal mechanical parameters to achieve this biological effect are still unknown. We assembled 46 blood clots in a closed in-vitro circulatory model. Clots were randomly divided into 7 groups, control group and six TUS groups of three frequencies (0.3, 0.5, 0.7 MHz) and six intensities (0.75, 1.5, 3, 237.7, 475, 950 W/cm2). Treatment was composed of 12 repetitions, 5 min US application and 3 min pause, lasting 93 min in total. Clots' weight and flow rate were measured before and after the treatment. Mean initial clot weight (0.318 ± 0.129 g) and flow (0.53 ± 0.31 ml/min) were comparable among the experimental groups. We found a final clot weights reduction (0.15 ± 0.05, 0.16 ± 0.06, 0.09 ± 0.07, 0.21 ± 0.09, 0.17 ± 0.09, 0.17 ± 0.07 and 0.18 ± 0.02 g in groups 1 through 6, respectively) and a flow increase (30.61 ± 19.76, 52.1 ± 25.44, 28.78 ± 8.15, 43.93 ± 20.03, 40.86 ± 18.25 and 45.10 ± 22.20 ml/min in groups 1–6, respectively) in all TUS groups. Clot weight change (%) and flow increase reveals that the TUS profile f = 0.5 MHz I = 1.5 W/cm2 was most efficacious. In the control group, clot weight change was +6.3% of baseline and flow increase of 4.4% of baseline, whereas −75.4% of baseline and 209.3% of baseline in the f = 0.5 MHz I = 1.5 W/cm2 profile were noted, respectively. Our study proved that TUS at low frequency (0.5 MHz) is most effective, whereas changing the intensity of TUS has only a minor effect on clot lysis magnitude. •Therapeutic ultrasound, without the use of a fibrinolytic drug, may be an effective method for clot lysis.•Low-frequency therapeutic ultrasound (0.5 MHz) is most effective for thrombolysis.•The intensity of therapeutic ultrasound has only a minor effect on the magnitude of clot lysis.•The proposed therapeutic ultrasound profile may be clinically applicable.