Evaluation of EmBlocker*

During heart surgery air emboli and solid emboli can enter the bloodstream as a
result of surgical actions. Clamping of the aorta, cannulation, the removal of
the aorta clamps and decannulation are all surgical actions which introduce
emboli into the aorta. Via the bloodstream the emboli will reach either the
aorta descendens or the carotids. Emboli in the cerebral arteries may cause
(temporary) obstructions. This can result into permanent neurological damage,
like neuro-psychological deficiency, or even a stroke. Air emboli are in
comparison to solid emboli less damaging, as they do not cause a permanent
obstruction, but in the brain even a temporary obstruction can cause damage.

To study the efficacy of the EmBlocker* in heart operations. The EmBlocker* is
placed in the thorax cavity and will reroute by the use of ultrasound the
emboli in the aorta curve to the aorta descendens, in order to reduce the
amount of emboli in the arteries of the brain. A reduction in the amount of
emboli in the arteries of the brain can result in a decrease of post-operative
neurological damage.

The study will be carried out single blinded in a population of 10 control
patients and 20 study patients. In the control group the patients will undergo
a standard heart operation (CABG or bypass operation), with Transcranial
Doppler monitoring and blood tests, but no EmBlocker* will be placed. The
results will be compared to the patients of the study group, undergoing a
standard heart operation (CABG or bypass operation) with transcranial Doppler
monitoring, blood tests and the use of the EmBlocker*.

The EM-blocker* shall be activated at different times during the operation.
These moments are mostly at times the aorta is manipulated, like during
cannulation and decannulation, the insertion of the cardioplegic needle and
aortic clamping.

The risks involved for the patients in the study group are the possibility of
thermal damage and an increase in the amount of emboli in the aorta descendens.
The risk for thermal damage is minimized by lowering the temperature of the
transducer by means of the continuous cooling of the transducer and by keeping
the exposure to this energy at the lowest possible level. Previous studies did
not reveal any thermal damage to patients. The major part of the created emboli
shall reach the aorta descendens without the intervention of the EmBlocker*.
Therefore the intervention of the EmBlocker* will only cause a relatively small
increase in the amount of emboli in the aorta descendens. Furthermore, mostly
air emboli will be rerouted and these are less dangerous in other organs than
the brain.