RESUMO
BACKGROUND: Cannulation of arch arteries (innominate, axillary or carotid) for arterial return during cardiopulmonary bypass is increasingly being used; however, the flow and pressure profile in the cannulated arteries remains unclear. The aim of this study was to evaluate the flow and pressure characteristics of arterial inflow through a carotid artery, especially with regard to operative and technical aspects, clinical outcomes, and side-related differences. METHODS: Between January 2005 and April 2008, 200 consecutive patients underwent elective aortic arch surgery at our facility. One hundred patients were assigned to undergo cannulation of the left and another 100 to undergo cannulation of the right carotid artery. Both groups were similar in terms of age, sex, and type of surgery. In all patients, arterial return was through a side-graft anastomosed to the carotid artery. The arterial line was also used for unilateral cerebral perfusion for brain protection during mild hypothermic circulatory arrest. The flow and pressure profiles in the arterial line and in the carotid artery were evaluated with regard to cardiopulmonary bypass flow rate and side of cannulation. RESULTS: No complications related to the cannulation of a carotid artery were observed. The arterial return was adequate in all patients, regardless of the side being cannulated. Because of low resistance (mean pressure<50 mmHg) in the carotid artery proximal to the inflow side-graft, the flow toward the aortic arch averaged 87+/-2% (range 84.4-92%) of the total flow volume (4.6+/-0.5 L/min), without a significant difference between the sides. However, the perfusion pressure in the arterial line was significantly higher when the left carotid artery was cannulated (216+/-30 mmHg vs. 205+/-30 mmHg; P=0.013). There was also a significant difference in the pressure in the distal carotid arteries, which, compared to the systolic blood pressure prior to cardiopulmonary bypass, increased by 30+/-24 mmHg on the left and decreased by 16+/-21 mmHg on the right (P<0.001). CONCLUSIONS: Both common carotid arteries are suitable for arterial cannulation; however, left-sided cannulation is associated with an increase in the pressure profile. Therefore, if vascular pathology does not dictate cannulation of the left carotid artery, the right carotid artery should be considered the site of choice.
