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. Anastomoses between the superficial vessels were also present but were less frequent and of smaller diameter.

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.

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., Culver City, CA), the authors have visualized, without complications, the normal orifices of various arteries and their bifurcations in 12 dogs, the atherosclerotic aortas of eight post mortem humans, and the coronary arteries of six post mortem humans. Potential applications of the instruments include more accurate diagnosis of occlusive diseases of the blood vessels, evaluation of such interventional procedures as angioplasty, intraoperative assessment of anastomoses, and safer laser surgery. The angioscope also enables the physician to combine pressure recording and dye injection simultaneously with the visualization of the inner walls of the vessels.