Development of a new catheter prototype for laser thrombolysis under guidance of optical coherence tomography (OCT): validation of feasibility and efficacy in a preclinical model.

In this feasibility study, a novel catheter prototype for laser thrombolysis under the guidance of optical coherence tomography (OCT) was designed and evaluated in a preclinical model. Human arteries and veins were integrated into a physiological flow model and occluded with thrombi made from the Chandler Loop. There were four experimental groups: placebo, 20 mg alteplase, laser, 20 mg alteplase + laser. The extent of thrombolysis was analyzed by weighing, OCT imaging and relative thrombus size. In the alteplase group, thrombus size decreased to 0.250 ± 0.036 g (p < 0.0001) and 14.495 ± 0.526 mm(2) (p < 0.0001) at 60 min. The relative thrombus size decreased to 73.6 ± 4.1% at 60 min (p < 0.0001). In the laser group, thrombus size decreased significantly to 0.145 ± 0.028 g (p < 0.0001) and 11.559 ± 1.034 mm(2) (p < 0.0001). In the alteplase + laser group, thrombus size decreased significantly (0.051 ± 0.026 g; p < 0.0001; 9.622 ± 0.582 mm(2); p < 0.0001; 47.4 ± 6.1%; p < 0.0001) in contrast to sole alteplase and laser application. The reproducibility and accuracy of the OCT imaging was high (SD <10%). Histological examination showed no relevant destruction of the vascular layers after laser ablation (arteries: 745.8 ± 5.5 μm; p = 0.69; veins: 448.3 ± 4.5 μm; p = 0.27). Thus, laser ablation and OCT imaging are feasible with the novel catheter and thrombolysis combining alteplase with laser irradiation appears highly efficient.