Stephen J.LurieMD, PhD, Senior EditorIndividualAuthor
To the Editor: Dr Van Dijk and colleagues1 demonstrated that patients who received their first
CABG without cardiopulmonary bypass (CPB) had a small improvement in the cognitive
outcome 3 months after the procedure, but the effects did not persist at 12
months. Cerebral microembolism and hypoperfusion, which are associated with
CPB, are the main mechanisms of brain injury in patients undergoing CABG.
Microembolic signals detected by transcranial Doppler ultrasound and echocardiography
monitoring during CPB can be directly associated with aortic manipulations,
but a large proportion of them are thought to represent air bubbles or microparticulate
emboli generated from the pump circuit and not completely eliminated by the
arterial line filters.2 Off-pump CABG is
associated with a marked reduction of the microembolic load during surgery
and, therefore, is believed to reduce cognitive impairment in those patients.
Malheiros SMF, Massaro AR, Buffolo E. Cognitive Outcomes Following Cardiopulmonary Bypass. JAMA. 2002;287(23):3077-3079. doi:10.1001/jama.287.23.3077