Abstract
OBJECTIVE: Atherosclerosis is a condition where arteries become constricted due to plaque deposition, impairing blood supply and potentially leading to stroke and other cardiovascular diseases. This study aims to develop a minimally invasive technology that combines focused ultrasound (FUS) with a catheter to remove arterial plaques through the cavitation effect. METHODS: In this investigation, via an ex vivo study in atherosclerotic plaque samples, we demonstrated that the onset of cavitation events can be enhanced by placing a catheter in the focal spot of the FUS field. Then, in a balloon injury-induced rabbit atherosclerosis model, FUS treatments with and without a catheter in the FUS field were performed on the femoral artery at 500 kHz with a 4 MPa peak negative pressure (PNP), 10% duty cycle and 100 Hz pulse repetition rate. RESULTS: In our ex vivo study using a catheter with a 0.67 mm diameter in the focal zone of an FUS transducer of 500 kHz center frequency, cavitation was initiated at a PNP of 1.9 MPa, whereas FUS alone required a PNP above 4 MPa to induce cavitation. In our in vivo study, FUS-only group demonstrated negligible lumen re-canalization effect by applying 4 MPa PNP, whereas using catheter-assisted FUS therapy resulted in maximum lumen re-canalization using the same PNP. Results were statistically significant between groups (p < 0.001). CONCLUSION: The results showed that catheter-assisted pulsed FUS therapy was effective in re-canalizing a blocked artery.