I appreciate the interest of Kestelli et al. [1] in our article published in the June 2010 issue of the Journal [2], and would like to draw their attention to two aspects. First, the title of their letter implies that it concerns the techniques of antegrade cerebral perfusion for brain protection during circulatory arrest, but it actually addresses the aspects of arterial return during cardiopulmonary bypass. Yet, the aim of our study was exclusively the comparison of rightand left-sided unilateral cerebral perfusion (UCP) for efficiency of cerebral protection rather than the suitability of a particular carotid artery for arterial return. The assessment of pressure in the left radial artery is of utmost importance in UCP, regardless if rightor left-sided perfusion is performed, because it reveals the efficiency of collateral pathways. As explained elaborately in the paper, our monitoring tools include therefore, amongst others, pressure measurement in both radial arteries. Nevertheless, the monitoring of the arterial return should not rely on the measurement of the pressure in the right radial artery alone, even if the right carotid or right axillary artery is cannulated with a side-graft, because the pressure is always higher on the directly perfused side. Cannulating the innominate artery that is very close to the aortic arch is surely the best haemodynamic, but for anatomo-pathological reasons, a rare option. Secondly, Kestelli et al. suggest, even without the support of any haemodynamic data, that the right carotid artery is a better approach for arterial return than the left carotid artery. This is in accordance with our study in which specific flow and pressure characteristics were examined during cardiopulmonary bypass [3]. This study was published elsewhere in 2010 and mentioned in our paper as reference number 23, leading to the conclusion that ‘we consider the right-sided cerebral perfusion as the standard, especially because the right carotid artery and the innominate artery are more suitable for cannulation than the left carotid artery’. We hope that this statement as well as the referenced study will be clear to attentive readers.