Nd-YAG laser fusion of human atheromatous plaque-arterial wall separations in vitro.

The hypothesis that thermal fusion of disrupted layers of atheromatous arterial wall can be achieved with a neodymium-yttrium aluminum garnet (Nd-YAG) laser was tested. Fresh postmortem human atheromatous plaque was separated from the underlying arterial wall to simulate a dissection in 1-cm2 arterial wall sections. With the plaque and underlying arterial wall subsequently compressed between glass slides, 17 W of continuous-wave Nd-YAG laser radiation were delivered through an optical fiber to the luminal surface of the plaque over a 4-mm2 area. Fusion of the plaque to the underlying arterial wall invariably occurred when tissue compression was applied during lasing and a thin blood film was present between the tissues. The load supported by tissue welds depended on plaque thickness, plaque composition, and exposure duration and was as great as 25 g. In postmortem, blood-filled, whole-artery segments, in which plaque had been completely separated from the media, this technique was applied intraluminally during angioplasty with a prototype balloon catheter. Lateral dispersion of Nd-YAG radiation from the termination of an optical fiber within the balloon allowed fusion of plaque to the underlying arterial wall during balloon inflation to 2 atm. Histologic examination of laser-treated tissues showed coagulation of tissues at the junction between the intimal plaque and media. It is concluded that thermal fusion of separated layers of atheromatous arterial wall can be achieved with Nd-YAG laser irradiation. This concept may be useful in the treatment of arterial dissections.