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The influence of blood flow velocity changes to postoperative cognitive dysfunction development in patients
Rasa Bukauskienė1, Edmundas Širvinskas1, Tadas Lenkutis1
1Department of Cardiothoracic and Vascular Surgery, Lithuanian University of Health Sciences, Kaunas, Lithuania.
Insights
Reduced middle cerebral artery blood flow velocity during heart surgery is linked to postoperative cognitive dysfunction. Blood flow velocity during bypass can help predict this condition, but glial fibrillary acidic protein is not a useful biomarker.
Area of Science:
- Neurology
- Cardiovascular Surgery
- Neuroscience
Background:
- Postoperative cognitive dysfunction (POCD) is a concern following cardiac surgery with cardiopulmonary bypass (CPB).
- Changes in cerebral blood flow may contribute to the development of POCD.
Purpose of the Study:
- To compare middle cerebral artery (MCA) blood flow velocity changes in patients with and without POCD before, during, and after heart surgery.
- To assess the predictive value of MCA blood flow velocity for POCD.
Main Methods:
- 100 patients undergoing elective coronary artery bypass grafting and/or valve surgery were evaluated.
- Neurocognitive tests were administered preoperatively and 7-10 days postoperatively.
- MCA mean blood flow velocity was measured at multiple time points: pre-surgery, post-anesthesia induction, before, during, and after CPB, and post-surgery.
Main Results:
- Patients who developed POCD had significantly lower MCA blood flow velocity after anesthesia induction and during CPB compared to those without POCD.
- MCA blood flow velocity post-surgery was also lower in the POCD group.
- MCA blood flow velocity during bypass was identified as a fair predictor of POCD (AUC=0.735).
Conclusions:
- Decreased MCA blood flow velocity during anesthesia induction and CPB is associated with POCD.
- MCA blood flow velocity during CPB holds diagnostic value for predicting POCD.
- Glial fibrillary acidic protein levels did not correlate significantly with MCA blood flow velocity or cognitive outcomes.
Background:
The aim of this study was to compare blood flow velocity changes in the middle cerebral artery before, during and after heart surgery with cardiopulmonary bypass for patients with and without postoperative cognitive dysfunction.
Materials And Methods:
A total of 100 patients, undergoing elective coronary artery bypass grafting or/and valve surgery enrolled in the study. A neurocognitive test evaluation included Adenbrooke, Mini-Mental State Examination and Trial Making test before and 7-10 days after surgery. Middle cerebral artery mean blood flow velocity was evaluated 1 day before the surgery, after anaesthesia induction, before cardiopulmonary bypass, at the beginning, ending and after cardiopulmonary bypass, and post surgery in intensive care unit. Blood samples for glial fibrillary acidic protein were measured after anaesthesia induction, 24 hours and 48 hours after surgery. According to neurocognitive tests results patients were divided in to two groups: patients with and without postoperative cognitive dysfunction.
Results:
Of the 100, 86 patients completed investigation. After induction, blood flow velocity of the middle cerebral artery was lower in postoperative cognitive dysfunction group (41.2; min 27.91, max 49.47) than in the H group (41.2, min 21.9, max 84.3) p = 0.034, and during cardiopulmonary bypass, blood flow velocity of the middle cerebral artery was lower in the postoperative cognitive dysfunction group (37.35, min 26.6, max 44.02) than the H group (42.3, min 20.1, max 86.5), p = 0.001. After the surgery, blood flow velocity of the middle cerebral artery was lower in the postoperative cognitive dysfunction group (40.7, min 29.7, max 50.4) than in the H group (45.3, min 34.12, max 59.88), p = 0.05. Results of cognitive tests had weak correlation (rho, 0.391) with middle cerebral artery's blood flow velocity after anaesthesia induction (p = 0.001) and during bypass (p = 0.018). The receiver operating characteristic analysis showed that the blood flow velocity of the middle cerebral artery during bypass (area under the curve = 0.735) was a fair predictor for postoperative cognitive dysfunction (p = 0.001). No significant correlations were found among glial fibrillary acidic protein, middle cerebral artery blood flow velocity, and cognitive tests results.
Conclusion:
Middle cerebral artery's blood flow velocity was decreased after anaesthesia induction and during cardiopulmonary bypass for patients with postoperative cognitive dysfunction comparing with their blood flow velocity preoperatively. Blood flow velocity during bypass has diagnostic value for postoperative cognitive dysfunction. Brain biomarker glial fibrillary acidic protein is not helpful in diagnosing postoperative cognitive dysfunction.
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