US Patent 4,589,419
United States Patent and Trademark Office
University of Iowa Research Foundation (Iowa City, IA, US)
The cardiac catheter of this invention combines in a single, thin tube, an acoustic transducer for determining blood flow velocity, and a separate lumen with a removable, flexible, radio-opaque guide wire, enabling the surgeon to locate the site of arterial blockage, evaluate the blockage, and assess the effect of the treatment.
Laughlin, Donald E.; Wilson, Robert F.; and Drews, Thomas A. Catheter for treating arterial occlusion. US Patent 4,589,419 filed November 01, 1984 and issued May 20, 1986. https://ir.uiowa.edu/patents/42