Preoperative Cerebral Hypoperfusion in the Left, Not in the Right, Hemisphere Is Associated With Cognitive Decline After Cardiac Surgery

Abstract

Patients who underwent cardiac surgery with reduced CBF velocity in the left MCA preoperatively are at greater risk for POCD. Left cerebral hypoperfusion may also represent an independent predictor of POCD in these patients. TCD evaluation may have substantial clinical benefits for the detection of patients at high risk of POCD after cardiac surgery.

Letter by Derakhshan Regarding Article, “Intraoperative Magnesium Administration Does Not Improve Neurocognitive Function Following Cardiac Surgery”

“…This is the same ratio as that recently reported by Messerotti Benvenuti et al 4 Fortunately, Messerotti Benvenuti et al's study included presurgical bilateral continuous transcranial Doppler sonography on all participants undergoing surgery (a total of 31 right-handed patients). After the operation, 14 of the 15 (45%) participants with diminished flow to their left middle cerebral arteries showed decreased performance in part B of the Trail Making Test.…”

“…Whereas, bimanual simultaneous drawing test in candidates for surgery would have guided the authors by focusing on the integrity of cortical circulation on the side opposite to the hand that drew the longer lines (ie, the dominant hemisphere), [3][4][5] sparing those destined to develop POCD after surgery.…”

Effects of Ncl. Basalis Meynert volume on the Trail‐Making‐Test are restricted to the left hemisphere

“…Additionally, performance in the TMT has been found to be specifically affected by hypoperfusion of the left hemisphere, which is in line with our finding of the left CH4 region specifically affecting TMT performance (Messerotti Benvenuti et al. 2012; Zanatta et al. 2012).…”

“…Referring to a report on the finding that hypoperfusion of the left hemisphere is associated with postoperative low performance in the Trail‐Making‐Test, we considered a focus on this subregion appropriate (Messerotti Benvenuti et al. 2012; Zanatta et al. 2012).…”

Response to Letter Regarding Article, “Intraoperative Magnesium Administration Does Not Improve Neurocognitive Function After Cardiac Surgery”

“…Dr Derakhshan also refers to the work of Messerotti Benvenuti et al 5 in asserting that flow to the right hemisphere is not relevant to postsurgical outcome. We think that such an assertion may be quite premature.…”