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Axillary artery cannulation for cardiopulmonary bypass reduces cerebral microemboli
Nasim Hedayati1, J Timothy Sherwood, Steve J Schomisch
1Division of Cardiothoracic Surgery, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, Ohio, USA.
Insights
Axillary artery cannulation during cardiopulmonary bypass (CPB) significantly reduces cerebral microemboli compared to aortic cannulation. This cerebroprotective effect may decrease stroke incidence in cardiac surgery.
Area of Science:
- Cardiovascular Surgery
- Cerebrovascular Research
- Surgical Techniques
Background:
- Aortic cannulation for cardiopulmonary bypass (CPB) is associated with cerebral microemboli from the ascending aorta.
- Aortic disease can prevent standard aortic cannulation.
- Axillary artery cannulation is explored as a potentially cerebroprotective alternative.
Purpose of the Study:
- To investigate the cerebroprotective potential of axillary artery cannulation compared to aortic cannulation during CPB.
- To evaluate microsphere deposition in the brain under different cannulation strategies.
Main Methods:
- Canine model with surgically altered carotid and subclavian arteries.
- Microspheres injected into the ascending aorta during four conditions: pre-reconfiguration, post-reconfiguration, CPB with aortic cannulation, and CPB with axillary cannulation.
- Analysis of microsphere distribution in brain, kidneys, and skeletal muscle.
Main Results:
- Axillary cannulation resulted in significantly fewer microspheres in the brain compared to aortic cannulation.
- 73% reduction in microspheres in the right brain and 40% in the left brain with axillary cannulation.
- No significant difference in microsphere deposition before and after aortic reconfiguration.
Conclusions:
- Axillary artery cannulation demonstrates cerebroprotective properties during CPB.
- Altered blood flow patterns with axillary cannulation may deflect emboli away from the brain.
- Increased use of axillary cannulation could potentially lower stroke rates in cardiac surgery.
Background:
Aortic cannulation for cardiopulmonary bypass (CPB) is linked to cerebral microemboli emanating from the ascending aorta. Aortic calcification or disease requiring replacement precludes aortic cannulation. Clinical experience with axillary artery cannulation led to the hypothesis that axillary cannulation may be cerebroprotective.
Methods:
Five mongrel dogs underwent a median sternotomy and isolation of the right axillary artery. The canine bicarotid brachiocephalic trunk was reconfigured by grafting the origin of the left carotid to the proximal left subclavian artery. Microspheres were injected into the ascending aorta during 4 conditions: before and after reconfiguration, CPB with aortic cannulation, and CPB with axillary cannulation. Brain, kidneys, and skeletal muscle were analyzed for microsphere distribution.
Results:
Each animal served as its own control for comparison of aortic and axillary cannulation. No significant differences were documented in microsphere deposition for prereconfiguration and postreconfiguration. In the right middle cerebral artery distribution, 2300 +/- 710 microspheres per gram were deposited during aortic cannulation, compared with 540 +/- 110 during axillary cannulation (P <.05). In the left middle cerebral artery region, 2030 +/- 330 microspheres per gram with aortic cannulation were reduced to 1320 +/- 240 with axillary cannulation (P <.05). Axillary cannulation resulted in 73% fewer microspheres in the right brain and 40% fewer microspheres in the left compared with aortic cannulation (P <.05).
Conclusions:
Axillary artery cannulation for CPB is cerebroprotective. Altered blood-flow patterns during axillary cannulation may produce retrograde brachiocephalic artery blood flow and competing intracerebral right-to-left collateral blood flow, deflecting emboli from the ascending aorta and arch toward the descending aorta. Expanded use of axillary artery cannulation during cardiac operations could decrease the incidence of stroke.
