Perfusion Pressure Cerebral Infarction Trial (PPCI)

STUDY HYPOTHESIS In cardiac surgery the volume of perioperative cerebral infarctions can be reduced by increasing mean arterial pressure (MAP) during the cardiopulmonary bypass procedure. BRIEF STUDY SUMMARY Heart surgery using cardiopulmonary bypass (CPB) can be complicated by injury to the brain. Previous studies using brain scans have reported small stroke-like lesions in up to 51% of patients after cardiac surgery. However, only 1-6 % of patients have permanent symptoms of severe brain damage. The majority of brain lesions seem to be caused by particulate matter (emboli) that wedge in blood vessels of the brain thereby compromising flow. In addition, insufficient blood flow to areas of the brain supplied by narrowed, calcified vessels may contribute. MAP during CPB usually stabilizes below the lower limit of cerebral autoregulation, which is accepted since sufficient total blood flow is guaranteed during CPB. The aim of the PPCI trial is to investigate if increased MAP during CPB can prevent or reduce the extent of brain injury after cardiac surgery. A beneficial effect could result from reduced embolic injury through increased blood flow in collateral vessels and/or by increased blood flow in calcified arteries. 180 patients scheduled for cardiac surgery will be randomly allocated to increased MAP (70-80 mm Hg) or \'usual practice\' (typically 45-50 mm Hg) during CPB, whereas CPB blood flow is intended equal and fixed in the two groups. Patients are examined before and 3-6 days after surgery with magnetic resonance imaging (MRI) brain scans, mental tests and by blood borne markers of brain injury. If higher MAP during CPB is beneficial, a change of practice can easily be implemented in the clinical routine.