Summary:The purpose of this study is to describe the use of angioscopes in flowing bloodstreams of animals and humans, to demonstrate the ability to precisely deliver laser energy to an intravascular target using visual guidance and to detemiine the information content and spatial content of angioscopy. Angioscopy was performed in 5 living dogs, 16 cadaver vascular segments, and 14 patients at the time of peripheral or coronary bypass surgery. Five canine femoral artery segments received angioscopically directed intravascular Nd:YAG laser irradiation. We were able to precisely direct the laser irradiation to predetermined intimal targets. Gross tissue injury varied from none to carbonization and vascular perforation, depending on incident energy. Using a variety of flexible fiberoptic endoscopes ranging in diameter from 1.5 to 3.7 mm, we were able to visualize intravascular structures including plaque, suture lines, venous valves, and thrombi in living patients. No patient incurred complications of any sort. We conclude that angioscopy using flexible en- doscopes can be performed safely, can provide clinically useful information, and may provide a means for delivering visually directed intravascular laser irradiation.

A pelvic radionuclide angiogram (PRAG) was obtained in addition to Tc-99m-labeled red blood cell scans in 18 studies (16 patients) of gastrointestinal bleeding. A bleeding focus adjacent to the bladder was found in the four studies in which the bladder region was seen on the PRAG; no perivesicular bleeding site was found in the 14 studies with a normal PRAG. It is concluded that the PRAG can be useful in locating pelvic bleeding sites, which can be missed on delayed images because of the superimposed bladder, and may be a useful addition to Tc-99m RBC studies for gastrointestinal bleeding.