Abstract
To establish the method of coronary laser angioplasty by Argon laser, we have investigated factors preventing from complications of intracoronary laser ablations, such as perforations, coronary spasms and severe arrhythmias.
Laser ablations were carried out in normal canine coronary arteries under beating heart with bare-ended probe (BEP) and metal tip probe (MTP) of 1.5mm in diameter. Perforations were observed in all cases delivered above 10 joules of laser energy by BEP. In case of using MTP, neither perforation nor coronary spasm could be observed under the condition of within 20 joules of laser energy. However perforations were observed in 4 (15%) out of 26 cases delivered above 20 joules of laser energy.
Furthermore, percutaneous transluminal laser thermal ablations were carried out in normal coronary arteries of the living dogs to evaluate morphological response of coronary artery to the laser. Laser ablations were carried out at 28 sites under the conditions of 5 watts in output and 2 seconds in ablation time using MTP. If laser ablations were done at the left main trunk (2.5±0.3mm in diameter), no complication was found in all cases, On the other hand, if laser ablations were made at the portion of LAD (6) or Cx (11) (2.0±0.4mm in diameter), coronary stenosis induced by thermal constriction was observed in 2 (12%) out of 17 cases. From these findings, MTP of 1.5mm in diameter should be applied for the coronary artery of which diameter is 2.0mm or more to avoid thermal vasoconstriction of the coronary artery.
