Marshall H. Lee

Hazards of angioscopic examination: Documentation of damage to the arterial intima

The fiberoptic scope is increasingly used in the coronary and peripheral arteries to quantitate the degree and type of arterial obstructive disease and to inspect the results of procedures such as bypass grafting and laser irradiation of obstructive lesions. Since little is known about this instruments potential complications, we passed a variety of fiberoptic scopes (1.8 to 3.6 mm outer diameter) in fresh postmortem pig coronary arteries and live monkey and canine peripheral arteries, and observed the intraluminal anatomy through the angioscope. No perforations were created, but ridges rising from the vascular luminal surface, avulsion of the endothelial lining, and small flaps attached at one end to the vessel wall were observed. Histologically, subintimal and medial tears were evident. Inserting large diameter scopes or making frequent passes (10 to 100) in coronary arteries increased intravascular injury. The use of small diameter flexible scopes or infrequent passes (less than 10) in the larger iliac and femoral arteries of live monkeys and dogs resulted in a lower frequency of myointimal sloughing or flap formation. Current fiberoptic scopes are not ideal angioscopes; they have a rigid tip, cannot be steered adequately, and are relatively stiff, resulting in a high probability of intraluminal injury, especially when used in small tortuous arteries. To decrease the risk of such injury, we recommend gentle manipulations while passing the scope and use of the smallest diameter scope possible. We further suggest limited use of the fiberscope, or at least limiting the number of passes in small vessels such as coronary arteries.

Laser recanalization in severe end-stage peripheral vascular disease

Abstract Application of lasers to vaporize coronary atherosclerotic obstruction was initially described in 1981. 1 Since then, the technique has been applied clinically to coronary arteries on an experimental basis. 2 This report objectively describes successful long-term laser recanalization using a catheter containing a laser-heated metal cap 3 in a patient with severe end-stage peripheral vascular disease.

Intravascular steerable guidewire for fiberoptic laser-heated metal cautery cap in dissolution of human atherosclerotic coronary disease

moment of her hospitalization, there were no hematologic data clearly consistent with ALL, and the chest x-ray film did not reveal lymph nodal enlargement. Therefore echocardiography was initially useful for locating an abnormal mass, leading to a rapid, accurate diagnosis. In fact, in similar cases, the exact diagnosis was delayed with regard to the onset of pericardial disturbances6 The disappearance of the mass after appropriate therapy, documented by echocardiography, is an additional interesting feature. In summary, the characteristic aspects of our case are represented by: (1) the onset of a T-ALL with a cardiac tamponade without signs of the hematologic disease and (2) the possible contribution of ,echocardiography to the diagnosis and follow-up of cases such as ours.

Coronary revascularization by a new coaxially-guided laser-heated metal cap system

The fiberoptic laser-heated metal cautery cap has been used effectively to vaporize coronary and peripheral atherosclerotic plaque obstructions.‘-4 However, easy placement of the thermal cap and safe vaporization of plaque in a coaxial fashion remain a concern.5 After testing several different catheter versions, a new cautery cap design was developed. The catheter consisted of an optical fiber (200 to 400 ccrn core diameter) attached to a metal cap (1 to 2 mm diameter) with a central extruding guide-wire tip (0.014to 0.018-inch diameter, Unicorn Cap-TM, Xintec Inc., Oakland, Calif.) (Fig. 1). This single unit device allows the operator easy placement and maneuverability inside the coronary artery and control of plaque vaporization. The cool tiny flexible guide-wire tip serves to guide

Laser Treatment of Coronary Artery Disease

Extension of the principle of microwave amplification by stimulated emission of radiation (maser) [1] afforded the development of laser (light amplification by stimulated emission of radiation) from devices that emit energized light within the visible spectrum [2]. Initial medical application of such photoradiation included retinal coagulation [3], tumor ablation [4], dermal surgery [5], and gastric hemostasis [6]. These advances have led to progress in the dissolution of obstructive atherosclerotic vascular disease with laser radiation [7]. In experiments carried out in our laboratories in the late 1970s performing balloon angioplasty in human cadaver coronary arteries [8], we found that balloon catheters could not traverse many subtotal coronary stenoses. Our initial concept of using lasers was to create a large enough channel through the obstructive lesion to allow the passage of a balloon catheter for coronary angioplasty. The application of laser as it has evolved during the past few years into the clinical treatment of coronary artery disease is described in the present report.