The collateral coronary circulation in the human fetus: angiographic findings.

Collateral circulation was studied in the heart of 20 normal human fetuses aged 19 to 39 weeks, using a radiographic technique. The radiograms showed the presence of coronary anastomoses ranging in size from 3 to 50 mu. The anastomoses were more abundant and of larger diameter in the interventricular septum and in the subendocardial layers.

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.

Angioscopy in vivo.

Recent developments in optical instrumentation have made possible the direct, three-dimensional viewing of intravascular structures. Using an angioscope (the Trimedyne Optiscope, Trimedyne Inc., Santa Ana CA) and a xenon cold lamp (the Xenon Cold Light Fountain, Karl Storz Endoscopy America, Inc.