Application Note #7
Conical lens-tipped Optical Fiber Helps Dissolve Highly Stable Blood Clots
In a collaborative effort between the Department of Neurology at The University of Miami —specifically, with Dr. Brant Watson, the patent holder— and OpusGen LLC (formerly VasCon) of Miami, Florida, conical lens-tipped optical fibers have been utilized endovascularly to facilitate dissolution of a type of blood clot that is extremely resistant to “clot-busting” (thrombolytic) enzymes. As Dr. Watson explained, the tightly organized clot structure inhibits entry of these enzymes. Dr. Watson’s method utilizes a conical lens-tipped fiber to illuminate the circumference of an arterial wall with a ring-shaped beam of ultraviolet laser light. This not only rapidly increases the diameter of the artery while it is occluded by a clot, but at the same time, the most enzymeresistant part of the clot is separated into individual cells (platelets). This process is called “dethrombosis” to distinguish it from the better-known “thrombolysis.” Dethrombosis allows blood to perfuse into the clot as it begins to disappear, and soon, blood flow is restored.
The entry into, and effectiveness of thrombolytic agents into clots is also much enhanced, but Dr. Watson reports that these medications may not be needed, at least acutely.
ULTRAPOL Fiber Lensing System offers accuracy and versatility in the surface shaping and lensing of optical components.
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greatly facilitates its local generation, resulting in dethrombosis of adjacent clots. Previously documented methods are based on either mechanical disruption (by “laser blasting”, “ultrasound”, “rotorooter”), direct extraction Image shows the output ring beam projected into a beaker filled with water. The blue fluorescence arises from dissolved impurities excited by (by syringe suction or the UV laser beam. “corkscrew”), or destabilization by drugs (thrombolytics), but these are not reliably effective (at best) and often The first “real world” results of this display serious side effects. process were presented at a conference on cerebral blood flow and metabolism ULTRA TEC is pleased that this in Amsterdam, in June 2005, where was development, requiring incorporation of shown the dilation effect of the UV beam accurate concentric angles for the delivered endovascularly via the production of actual field-use conical lens-tipped optical fibers, was microcatheter/conical tip optical fiber successfully performed on our device constructed by OpusGen. ULTRAPOL fiber lensing system, which is a sophisticated shaping and polishing The concomitance of “dethrombosis” device for optical fiber tips. The very first mediated by nitric oxide in treating samples were done at Ultra Tec’s ischemic stroke was explained in demonstration laboratory, and the October 2005 at an Interventional technology was quickly moved to Neuroradiology Conference in Venice, OpusGen where a minimum of training Italy. Nitric oxide is produced naturally was sufficient for OpusGen personnel to in blood vessels, but the UV laser continue. Shown below is diagram featured in Dr. Brant Watson’s poster for the Amsterdam conference, explaining some of the technical considerations, including determination of proper lens angles. N1 α
O Optical fiber, n1 = 1.475
P θ1 θ 1 θ1
α ω
θ1 δ
α α
β
Q
γ Saline medium, n2 = 1.333
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N2
O*