Novel laser-vascular welding to close catheter sheath hole after catheter intervention: Welding against vascular model and fiber-based back scattering monitoring

In order to attain complete seal of catheter sheath hole just after catheter intervention, we applied laser welding technique. We employed combination of diode laser (wavelength: 810nm) irradiation and indocyanine green stain to enhance heat generation on the stained surface. We studied laser sealing of catheter sheath hole on an ex vivo vascular model using porcine carotid artery. We successfully demonstrated the sheath hole closure in this welding in the model with 1.8W, 8s diode laser irradiation. In this case, we estimated 78°C of the maximum temperature at welding surface by thermal conduction calculation. Collagen fiber melting was found in welding region. To know vascular wall at the fiber tip to perform laser welding in blind procedure, we constructed fiber-optic backscattering light measurement system. We used green He-Ne laser light (543nm) to distinguish hemoglobin concentration in the tissue. We obtained tissue discrimination at fiber tip in blind procedure. We think our particular laser welding in combination with novel tissue discrimination technique at the fiber tip may attain the catheter sheath hole closure with sufficient mechanical strength in blind procedure.