Combined low-frequency ultrasound and streptokinase intravascular destruction of arterial thrombi in vivo.

To prevent a distal embolization in the course of ultrasound (US) angioplasty, we combined US thrombus disruption in peripheral artery in vivo with simultaneous administration of streptokinase (SK). Acute thrombosis was induced in the femoral arteries of 23 dogs. Two hours after thrombus formation, thrombus destruction was performed using US (36 kHz) and by a combined US+SK (75,000 U/kg) administration. The results showed that thrombi were disrupted completely by 1.5 ± 0.5 min US. A combined US+SK action resulted in activation of fibrinolysis, as indicated by the increase in the content of fibrinogen and fibrin degradation products and D-dimers by a factor of 1.5-2.0 after 120 min from start of treatment compared with the SK lysis. The duration of clot destruction did not change; the distal embolization was not indicated; platelet aggregation activity dropped after thrombus destruction. In summary, intravascular thrombus destruction by a combined US and SK action in vivo is accompanied by enhancing the enzymatic fibrinolysis and lowering the platelet aggregation activity that assists in preventing the distal embolization of the resulting clot debris.

Method for disruption and re-canalization of atherosclerotic plaques in coronary vessels with photothermal bubbles generated around gold nanoparticles.

BACKGROUND AND OBJECTIVES: Rapid and safe re-canalization of totally occluded coronary vessels, especially those with the calcified plaques, represent a challenge for cardiology. STUDY DESIGN/MATERIALS AND METHODS: We have suggested to employ photothermal microbubbles (PTMBs) that are generated around injected to plaque or thrombus gold nanoparticles with a short laser pulse for selective mechanical disruption and removal of the plaque tissue and without thermal and mechanical damage to arterial wall. PTMBs were generated in vitro around 30-250 nm gold spheres and with 10 nanoseconds laser pulse at 532 nm in three models: the layer of the living fibroblasts, the epoxy layers, and human arteries with plaques. RESULTS: In all three models, complete removal of the material was observed after 1-10 single laser pulses. The size of cleared zones (20-220 microm) was found to be 500-1,000 times bigger than the size of the nanoparticles applied. PTMB generation did not increase the temperature of the microenvironment outside PTMB and the debris size was below 2 microm. CONCLUSIONS: New proposed method for non-thermal mechanical and localized removal of plaque tissue with PTMB can provide safe and rapid re-canalization of totally occluded and calcified arteries without collateral damage.