A new design of spaced optical fibers for coronary laser catheters provides increased tissue ablation in comparison to the traditional closely packed fibers catheter. Slow advancement rates during lasing with the new OS catheter are crucial for achievement of adequate plaque debulking.

Current multiple-optical-fiber catheters for excimer laser coronary angioplasty (ELCA) emit pulsed light at 308nm from a xenon chloride (XeC1) excimer laser to remove plaque in occluded arteries. Because the fiber ends, arranged in a closestpacked array, do not cover the entire surface of the catheter tip, these devices ablate holes typically holes typically 7 5-80% of the catheter tip diameter. To increase the ablation effectiveness, an optimally spaced fiber catheter has been designed in which the fiber-to-fiber spacing is increased precisely enough so as to cover the entire catheter tip area with fibers. In vitro and in vivo testing compared the optimally spaced catheter to catheter models currently in cliiucal use. Although device handling characteristics were found to be identical, the optimally spaced devices removed a significantly greater amount of tissue. This may offer a technical advantage in a clinical setting.