Strategies for the reduction of cerebral microembolism during transmyocardial laser revascularization.
OBJECTIVE
During transmyocardial laser revascularization (TMLR), multiple microembolic signals (MES) can be detected in cerebral arteries. We sought to characterize composition and clinical relevance of these MES and to evaluate strategies to reduce cerebral microembolization during TMLR.


METHODS
TMLR was performed in pigs. Laser energy was set to 4-10 J (group A) or 80 J (group B). Oxygen concentration was varied between 21 and 100%. MES were recorded in the ophthalmic artery. Brain and spinal cord were investigated histologically after 10 days.


RESULTS
More MES could be detected during high- compared to low-energy laser procedures. Ventilation with 100% oxygen reduced the number of MES. No lesions were found on histology.


CONCLUSIONS
The number of MES depends on the laser energy. Laser-induces cavitation-effects lead to an additional release of nitrogen bubbles. Thus, the microembolic load can be reduced by ventilation with 100% oxygen and by decreasing the laser energy.
Gerriets
Tibo
T
Department of Neurology, Justus-Liebig University Giessen, 35390 Giessen, Germany.
Grossherr
Martin
M
Misfeld
Martin
M
Nees
Urs
U
Reusche
Ernst
E
Stolz
Erwin
E
Sievers
Hans H
HH
Kaps
Manfred
M
Kraatz
Ernst G
EG
D000818:Animals; D001921:Brain / Q000473:pathology; D004453:Echoencephalography; D020766:Intracranial Embolism / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D053685:Laser Therapy / Q000009:adverse effects* / Q000379:methods; D009204:Myocardial Revascularization / Q000009:adverse effects* / Q000379:methods; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D013552:Swine
D010100:Oxygen