LASER-ASSISTED VERSUS MECHANICAL RECANALIZATION OF PERIPHERAL OCCLUSIONS - A RANDOMIZED TRIAL
Authors: Jm Tobis, R Conroy, Ls Deutsch, I Gordon, J Honye, M Berns
Journal: Circulation (1990)

Laser-Assisted Versus Mechanical Recanalization of Femoral Arterial Occlusions Jonathan M. Tobis, MD, Robert Conroy, MD, Larry-Stuart Deutsch, MD, Ian Gordon, MD, PhD, Junko Honye, MD, PhD, Jeff Andrews, BA, Glen Profeta, BS, Sherrie Chatzkel, MD, and Michael Berns, PhD A randomized clinical trial was performed to test the hypothesis that a laser-heated probe is supe- rior to standard techniques to reopen occluded femoral arteries. Twenty patients were treated with a standard guidewire and balloon dilation method. In a second group of 20 patients, the la- ser probe was initially used as a nonheated me- chanieal device. If the probe was unsuccessful in mechanically reopening the artery, an Argon la- ser was activated to heat the probe. The mean length of occlusion was 15.9 f 10.3 cm. The success rate for the laser probe was 15 of 20 (75%), which was not significantly different from the standard method, 19 of 20 (95%). Most of the success in the laser-probe group was due to the probe’s mechanical properties. The la- ser probe was successful as a cold, mechanical device in 13 of 15 (87%) arteries. It was neces- sary to heat the probe in 5 patients. When heat- ed, the laser probe assisted recanalization in 2 but perforated the artery in 3 cases. The results of thii randomized trial do not support the hypotheses behind the use of the thermal laser probe. The laser probe functions primarily as a mechanical device. The thermal activation does not significantly improve the suc- cess rate without increasing the risk of perfora- tion. This small additional benefit does not justify the large cost of current thermal laser devices. This controlled study also demonstrates a higher success rate in long occlusions than previous re- ports of mechanical balloon recanalization. This is due to a combination approach of retrograde and anterograde probing of the occluded seg- ment. (AmJ Cardiol 1991;68:1079-1086) From the Divisions of Cardiology, Radiology and Surgery, University of California, Irvine, Long Beach Veterans Administration Hospital, and Beckman Laser Institute, Orange, California. This study was sup ported by Grant RR01192 from the National Institutes of Health, Bethesda, Maryland, and Grant NOO014-90-C-0029 from the Oflice of Naval Research, Arlington, Virginia. Manuscript received April 15, 1991; revised manuscript received and accepted June 17,1991. Address for reprints: Jonathan M. Tobis, MD, Cardiac Catheter- ization Laboratory, University of California, Irvine Medical Center, 101 City Drive South, Route 81, Orange, California 92613-4091. he use of laser energy to ablate atherosclerosis and assist peripheral or coronary angioplasty has caught the imagination of the medical pro- fession and the patient population. As of June 1990, it was reported that 30,000 cases of laser-assisted thermal angioplasty had been performed.’ In response to early reports of a high perforation rate with bare fiber cathe- ters,2>3 most of the procedures have been performed with a fiberoptic conduit with a metal cap at the distal end.4l5 This device uses laser energy to heat the metal tip which produces a thermal-tissue interaction to per- form the arterial recanalization. The theoretical as- sumptions of the mechanism of action of the laser-as- sisted thermal probe are: (1) that it reopens occluded arteries by tracking the original lumen; and (2) the thermal energy ablates atherosclerotic tissue, thereby reducing the mass of atheroma which helps to recana- lize the artery and also improve the long-term patency rate.‘j Despite these theories and the high rate of use of these Food and Drug Administration approved devices, there has been no randomized clinical trial to demon- strate any benefit of the thermal probes over standard techniques for arterial recanalization. The purpose of the present study was to conduct a randomized clinical trial to test the hypothesis that (1) the laser-assisted probe, either as a mechanical or thermal device, is su- perior to standard guidewire and catheter techniques currently in use; and (2) there is an additional benefit to using thermal energy to recanalize peripheral arteries compared with the mechanical effect of the probe. T METHODS Patient selection: Patients were recruited to partici- pate in this study if they had symptoms of claudication and angiographic evidence of an occluded superficial femoral artery. Only patients with complete occlusions on angiography were included in this protocol; stenotic lesions were not treated by the laser probe and were excluded from this study. In addition, the length of the occlusion or the degree of calcification was not used to exclude patients. At least 1 patent tibia1 vessel for run- off was a criterion for inclusion. The primary end point for a successful result was recanalization of the occlud- cd segment of artery with angiographic evidence of di- rect flow between the proximal and distal lumens. LASER ANGIOPLASTY