A randomized study of the influence of perfusion technique and pH management strategy in 316 patients undergoing coronary artery bypass surgery. II. Neurologic and cognitive outcomes.

Abstract

This double-blind, randomized comparison of pulsatile or nonpulsatile perfusion and alpha-stat or pH-stat management during cardiopulmonary bypass was designed to assess postoperative central nervous system outcomes. Neurologic and cognitive testing was conducted before the operation and 7 days and 2 months after the operation in 316 patients having coronary artery bypass and in a reference cohort of 40 patients having major vascular and thoracic operations. As detailed in part I of this study, mortality in patients having coronary bypass was 2.8%. The incidence of stroke was 2.5% and did not differ among bypass groups. Mortality was 2.5% for the major surgery cohort. The incidence of cognitive (p = 0.003) and either neurologic or cognitive dysfunction (p = 0.0002) was higher at 7 days for the coronary bypass group than for the major surgery cohort. The incidence of neurologic dysfunction remained higher (p = 0.050) at 2 months in the coronary bypass group. Cognitive dysfunction at 2 months was less prevalent after 90 minutes of cardiopulmonary bypass in patients managed with alpha-stat than with pH-stat strategy (27% versus 44%, p = 0.047). Postoperative central nervous system dysfunction is more prevalent in patients having coronary bypass than in those having major operations. Pulsatility has no effect on central nervous system outcomes, but alpha-stat management is associated with a decreased incidence of cognitive dysfunction in patients undergoing prolonged cardiopulmonary bypass.