Optimization of the excimer laser assisted non-occlusive anastomosis (ELANA) flap retrieval rate.

ABSTRACT

BACKGROUND AND OBJECTIVES: A key element in the Excimer Laser Assisted Non-occlusive Anastomosis (ELANA) technique is the retrieval of a disc ("flap") of artery wall from the anastomosis by the laser catheter tip. We assessed if the flap retrieval rate could be optimized. METHODS: We used a specially designed in vitro model using rabbit aortas. We tested three essential elements of the technique (1) laser energy (10, 13, 15, or 18 mJ), (2) pressure on the catheter (0, 0.1, 0.2, or 0.4 N), and (3) number of lasing episodes (1 or 2). We made 2,280 anastomoses using different combinations of settings. With a logistic regression model we assessed the influence of each parameter. Current clinical settings (10 mJ, 0.2 N, 1 episode) were reference categories. RESULTS: Flap retrieval rate using conventional settings was 86.7%, equivalent to earlier reported clinical data. A significantly higher flap retrieval appeared when laser energy was increased to 13 mJ (OR 3.0, 95% CI 1.8-4.8), 15 mJ (OR 3.2, 95% CI 1.9-5.3), and 18 mJ (OR 3.7, 95% CI 2.2-6.2). A second lasing episode also significantly increased flap retrieval (OR 2.1, 95% CI 1.4-3.0). However, if we increased energy to 15 or 18 mJ, the effect of a second laser episode was insignificant. When the catheter was pushed down with 0.4 N, flap retrieval decreased significantly in all subgroups (OR 0.07, 95% CI 0.04-0.14). CONCLUSION: The flap retrieval of the ELANA anastomosis technique can be optimized to 100% by setting the laser energy at 15 mJ. However, safety studies are necessary before clinical application. A second lasing episode of 10 mJ is a good alternative to increase the flap retrieval. Moreover, the surgeon should be trained to apply not more than 0.2 N on the catheter.