Initial clinical evaluation of carotid artery laser endarterectomy.

Clinical study of carotid artery laser endarterectomy began April 15, 1988. This report describes the first 10 cases that were performed in nine patients (five men and four women, mean age 70 years). Indications were asymptomatic stenosis (5), transient ischemic attacks (4), and stroke in evolution (1). There were two emergency cases and eight elective cases (including one reoperative case). Surgical exposure, systemic heparinization, vascular control, and a longitudinal arteriotomy were used. The cleavage plane between atheromas and media was developed with argon ion laser radiation (488 and 514.5 nm) directed through a 300 microns quartz fiber at power 1.0 W. Laser radiation was used to cut the atheromas out of the arteries and weld the end points. Residual atheromatous debris were vaporized with individual laser exposures. Arteriotomies were closed with sutures, and blood flow was restored. The endarterectomies were 3.9 +/- 1.1 cm long and required 330 +/- 97 joules. Mean clamp time was 22.5 +/- 7.9 minutes. Shunts were used in two cases. There were no arterial perforations or injuries as a result of laser light. Complications were hematoma (1), respiratory arrest (1), and transient neurologic deficit (1). Carotid endarterectomy is technically feasible with argon ion laser radiation. In the present series, postoperative observations, averaging 12 months and ranging from 5 to 19 months, have shown satisfactory results. No angiographic follow-up examinations were carried out.

Initial trial of argon ion laser endarterectomy for peripheral vascular disease.

In the initial of open laser endarterectomy, 16 patients underwent 18 reconstructions for claudication (13 patients), rest pain (3 patients), and gangrene (2 patients). The mean (+/- SD) preoperative ankle arm index was 0.53 +/- 0.18. The laser endarterectomies were aorto-bi-iliac (1 patient), iliac (1 patient), superficial femoral (7 patients), profunda femoral (7 patients), and popliteal-posterior tibial (2 patients). All operations included surgical exposure, vascular control, administration of heparin, and an arteriotomy. Atheromas were dissected from arteries with argon ion laser radiation (power, 1.0 W). End points were welded with laser light. Arteries were closed primarily. The laser endarterectomies were 6 to 60 cm long and required 168 J to 2447.5 J. All patients had symptomatic relief, with a postoperative ankle arm index of 0.97 +/- 0.10. There were no arterial perforations from laser radiation. Surgical complications included early thrombosis requiring thrombectomy (3 patients) and hematoma requiring evacuation (1 patient). The laser endarterectomies have an 88% patency at 1 year. Open endarterectomy can be performed with laser radiation. A larger clinical trial is necessary to define the indications for laser endarterectomy in peripheral vascular disease.

Comparison of continuous-wave lasers for endarterectomy of experimental atheromas.

The standard surgical lasers, argon ion, neodymium-yttrium aluminum garnet, and carbon dioxide, are often operated as continuous wave lasers with specific uses. Clinical trials of laser therapy for arteriosclerotic cardiovascular disease are underway with all three lasers. Therefore, we compared these three lasers under controlled experimental conditions. A thoracoabdominal exploration was performed in 17 arteriosclerotic rabbits. The aorta was isolated, heparin administered, and multiple endarterectomies were performed in each rabbit with each of the lasers. A line of laser craters was created at the proximal and distal ends of an atheroma. Continuous-wave laser radiation was used to connect the craters and thereby form proximal and distal end points. The plaques were dissected free from the aorta with laser light and the end points were fused by laser. The aortas were removed for light microscopy and the animals were killed. The endarterectomy surfaces and end points were serially sectioned and graded according to light microscopic findings (1 = worst, 4 = best). Argon ion laser endarterectomy (N = 16) required 106 +/- 10 J/cm2. The surface score was 3.5 and end point score 3.4. Neodymium-yttrium aluminum garnet laser endarterectomy (N = 13) required 1,289 +/- 115 J/cm2 with a surface score of 2.4 (p less than 0.001 from argon ion) and an end point score of 1.3 (p less than 0.001 from argon ion). Carbon dioxide laser endarterectomy (N = 9) required 30 +/- 5J/cm2 with a surface score of 2.0 (p less than 0.001 from argon ion) and and end point score of 1.6 (p less than 0.001 from argon ion). Perforation occurred in one of 16 argon ion studies (technical error, not laser), in 11 of 13 neodymium-yttrium aluminum garnet studies, and in six of nine carbon dioxide studies. This study demonstrates that of the currently available clinical continuous-wave lasers, the argon ion laser is superior for endarterectomy of experimental atheromas.

Experimental arteriosclerosis treated by argon ion and neodymium-YAG laser endarterectomy.

The argon ion laser (488 and 514.5 nm) and the Nd-YAG laser (1.06 micron) have been used in most studies of laser radiation for treatment of arteriosclerotic cardiovascular disease because their beams can be directed through a delivery fiber. We compared the effects of argon ion and Nd-YAG lasers in vivo on arteriosclerotic rabbit aortas with open laser endarterectomy. A thoracoabdominal exploration was performed in 16 rabbits to isolate the aorta. Laser beams were directed through delivery fibers to produce a line of laser craters at the proximal and distal ends of an atheroma. The lines of laser craters were connected by continuous-wave laser radiation to loosen the plaque and the cleavage plane was developed within the media by continuous-wave laser radiation. End points were fused by continuous-wave laser radiation and the aortas were harvested for light and scanning electron microscopy. Argon ion laser endarterectomy (eight rabbits) required an energy density of 98 +/- 19 J/cm2. Nd-YAG laser endarterectomy (eight rabbits) required an energy density of 1147 +/- 129 J/cm2. Perforation did not occur with the argon ion laser but occurred in six of eight Nd-YAG experiments. Even depths of plaque removal resulted from argon ion laser endarterectomy but not from Nd-YAG laser endarterectomy. Gross and microscopic grading of the aortas showed that argon ion endarterectomy surfaces were significantly better than Nd-YAG surfaces (p less than .05). Similarly, argon ion end points were significantly better than Nd-YAG end points (p less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental arteriosclerosis treated by conventional and laser endarterectomy.

Open laser endarterectomy was compared to standard surgical endarterectomy in the rabbit arteriosclerosis model. The aorta was exposed by a thoracoabdominal exploration in 16 rabbits. In Group I (8 rabbits), a conventional endarterectomy (CE) was performed with standard vascular instruments. In Group II (8 rabbits), laser endarterectomy (LE) was performed with an argon ion laser (488 nm and 514.5 nm) at a power of 1.0 W. Aortas were fixed, serially sectioned (6 micron) and stained (H +/- E) following each procedure. Gross and light microscopic examination revealed identical results for the endarterectomy surfaces of CE and LE. The proper cleavage plane within the media was developed with both techniques and the remaining arterial wall was not damaged with either procedure. The end points of LE were consistently superior to those of CE because of phototherapy fusion. The LE end points were tapered and the intima was fused. Intimal flaps were seen in 2/8 CE experiments and the remaining end points exhibited an uneven transition. LE required an average energy density of 124 +/- 9 J/cm2. We conclude that LE provides a satisfactory method for the in vivo evaluation of laser radiation upon arteriosclerotic arteries. LE may be the way to begin clinical laser trials.

Laser endarterectomy.

Laser radiation can be applied directly at a diseased artery to dissect the plaque away from the media and perform an open endarterectomy. The appropriate cleavage plane within the media can be achieved with the laser beam for precise reconstruction of the artery. Laser endarterectomy offers a technique for the study of laser radiation upon arteriosclerosis and may become a new modification of a standard surgical technique.

Laser applications to arteriosclerosis: angioplasty, angioscopy, and open endarterectomy.

We have studied laser radiation of arteriosclerotic cardiovascular disease to determine the best technique for evaluation. Rabbits with arteriosclerosis were treated by intraluminal laser angioplasty (N = 8), laser angioscopy (N = 2), and open laser endarterectomy (N = 5). All studies were performed with an argon ion laser delivering energy through a 400-microns quartz fiber. Power delivered was varied in order to determine the best value for this animal model. Following angioplasty, perforation was seen in three rabbits (in one case, it was due to mechanical trauma from the fiber optic), and early thrombosis occurred in two rabbits. Plaques were vaporized by angioscopy, but the depth of laser beam penetration or angle of incidence could not be controlled. Open laser endarterectomy gave consistently good results with removal of an arteriosclerotic plaque within the media. The optimum power was found to be 1.0-2.0 W. Endarterectomy required an energy density of 100-140 J/cm2. We conclude that open laser endarterectomy can be a standardized technique for the in vivo evaluation of laser radiation upon arteriosclerotic lesions.

Cardiac assist by extracorporeal membrane oxygenation with in-line left ventricular venting.

We have used a canine heart failure model and extracorporeal circulation to study the limitations of extracorporeal membrane oxygenation (ECMO) for the treatment of cardiac failure. ECMO does not routinely achieve total biventricular bypass and does not effectively decompress the failing left ventricle. The addition of an in-line left ventricular vent (ECMO-lv) provided total biventricular bypass and complete left ventricular decompression in every experiment. ECMO-lv merits consideration as a biventricular bypass system for total mechanical support of the failing heart.