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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.

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SUMMARYEffects of three representative vasodilators on peripheral and cardiac hemodynamics were studied in 20 patients with heart failure due to acute myocardial infarction (PCWP>18mmHg, Cl>2.20 L/min/m2) using venous occlusion plethysmography and a SwanGanz catheter. Sublingual isosorbide dinitrate (ISDN) significantly increased calf venous capacitance (CVC) from 5 to 60min (p<0.01) and calf blood flow (CBF) in the initial 15min (p<0.05), while simultaneously lowering PCWP (p<0.05) and central venous pressure (p<0.05). Calf vascular resistance (CVR), cardiac index, blood pressure, and total systemic peripheral resistance (TSPR) were not affected significantly. Nitroglycerin ointment (NGO) significantly decreased CVR (p<0.05) and increased CVC (p< 0.05) from 60 to 240min, simultaneously with lowering of PCWP (p<0.01), central venous pressure (p<0.05), and TSPR (p<0.05). Oral prazosin (Pz) increased CBF (p<0.01) and CVC (p<0.05) from 60 to 240min, simultaneously with significant lowering of PCWP (p<0.01) and TSPR (p<0.05), resulting in increased stroke work index (p<0.05). These data confirm that ISDN predominantly causes capacitance vessel dilatation and reduce excessive venous return, while Pz and NGO dilate not only capacitance vessels but also resistance vessels, consequently reducing systemic vascular re-