From angiography to angioscopy: informal discussion.

Devices for visualizing blood vessels have evolved from a rigid, illuminated tube (1913), to a tube with an added convex lens (1922), to one with a transparent inflatable balloon for displacing blood from the line of vision (1943), to a flexible angioscope (1960s). Recent fiberoptic developments make it possible to visualize the orifices of the coronary arteries and simultaneous laser angioplasty. The characteristic fluorescence of hematoporphyrin derivative under ultraviolet light has been visualized angioscopically in experimental atherosclerotic plaque, where it accumulates and acts as a marker. However, several requirements need to be met in order for angioscopy to fulfill its therapeutic possibilities in angioplasty, thrombolytic therapy, intraoperative inspection of vascular anastomoses, and its diagnostic potential in distinguishing plaques from clots and pulmonary embolisms from other obstructions. These requirements are: (1) variously-sized angioscopes to accommodate iliac, femoral, renal, and coronary arteries; (2) percutaneous introducers in the various sizes to prevent back-bleeding; (3) a more flexible, easily manipulated fiberoptic; (4) a sufficiently inflatable balloon tip; (5) cross hairs and reference points in the optical system; and (6) optimal focal lengths for the areas to be visualized.