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Stay off-pump and do not touch the aorta!

Volkmar Falk
DOI: http://dx.doi.org/10.1093/eurheartj/ehp527 278-280 First published online: 4 December 2009

One of the major drawbacks in contemporary on-pump coronary artery bypass surgery is the inherent risk of intraoperative stroke. In addition, neurophysiological dysfunction and neurobehavioural changes have been reported in variable frequencies following on-pump bypass surgery. Cardiopulmonary bypass (CPB) causes a systemic inflammatory response, haemodilution, change in vascular resistance, absence of pulsatile flow, and large volume shifts. As a result, temporary cerebral oedema can be seen in magnetic resonance imaging (MRI) studies early after on-pump bypass surgery and has been identified as the substrate for what was termed ‘pump head’ in the past. Refinements of CPB circuits using biocompatible surfaces, the use of less traumatic oxygenators, and the addition of filters as well as the establishment of standardized perfusion protocols have improved the results of on-pump surgery. Despite these advances, CPB remains one major source for gaseous microembolization.1,2 Retransfusion of shed mediastinal blood during on-pump surgery has long been recognized as an additional source of embolization by fat particles and activation and derangement of the clotting cascade.

Manipulation of the ascending aorta such as partial or total clamping and cannulation required for installation of CPB can cause additional solid emboli especially in the presence of atherosclerotic disease.3,4 Numerous studies have shown embolic showers in transcranial Doppler during cannulation and clamping and declamping manoeuvres. The release of particulate emboli correlates in particular with the release of the aortic cross-clamp.5 Gerriets et al. have reported a randomized controlled trial to demonstrate the impact of two different methods to decrease the embolic load during on-pump bypass surgery with partial aortic clamping in a …

*Corresponding author. Tel: +41 44 255 32 98, Fax: +41 44 255 32 98, Email: volkmar.falk{at}usz.ch