Original article: cardiovascular
Neurocognitive deficit following coronary artery bypass grafting: a prospective study of surgical patients and nonsurgical controls

https://doi.org/10.1016/j.athoracsur.2004.03.006Get rights and content

Abstract

Background

To objectively measure long-term neurocognitive deficit in patients undergoing coronary artery bypass grafting and compare the findings with nonsurgical controls.

Methods

We prospectively measured neurocognitive function in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (n = 104; mean age 64.1 years old; EuroSCORE 2.7 [means]). A cohort of age- and sex-matched patients (n = 80; mean age 63.4 years old) served as nonsurgical controls. After CABG, neurocognitive function was serially reevaluated at 7-day (n = 104), 4-month (n = 100), and 3-year follow-up (n = 88). Neurocognitive function was objectively measured by means of cognitive P300 evoked potentials. Additionally, standard psychometric tests were performed (Trailmaking Test A, Mini Mental State Examination).

Results

As compared to preoperative measures (364 ± 36 ms), cognitive P300 evoked potentials were prolonged (=impaired) at 7-day (381 ± 36 ms; p = 0.001), 4-month (378 ± 31 ms; p = 0.08), and 3-year follow-up (379 ± 35 ms; p = 0.002), respectively. Trailmaking Test A was abnormal, as compared to preoperative, at 3-year follow-up (p < 0.001). Before the operation, surgical patients were fully comparable in P300 measures to nonsurgical controls (363 ± 32 ms; p = 0.362). Most importantly, throughout the entire postoperative follow-up cognitive measures in surgical patients were prolonged (=impaired) as compared with controls (7-day p = 0.001; 4-month p = 0.002 and 3-year p = 0.003, respectively). In stepwise multivariate regression analysis, neurocognitive deficit at 4-month follow-up (p < 0.001), age (p = 0.012), and persistent atrial fibrillation (p = 0.024) were predictive for long-term neurocognitive deficit at 3-year follow-up.

Conclusions

As shown by means of objective measures, and in comparison to nonsurgical controls, coronary artery bypass grafting with cardiopulmonary bypass grafting causes long-term neurocognitive deficit.

Section snippets

Patients

After approval was obtained by the Ethics Committee of the University of Vienna, 105 patients who underwent elective coronary artery bypass grafting at our department between January and December 1999, gave their written informed consent and were enrolled in this prospective study. Exclusion criteria were a history of one of the following medical conditions [1]: prior stroke with residual deficit [2], uncontrolled hypertension [4], carotid artery stenosis 75% [4], psychiatric illness requiring

Results

One hundred four patients undergoing isolated coronary artery bypass grafting at our institution were prospectively followed. The baseline characteristics of patients as well as controls are given in Table 1.

Comment

When compared with nonsurgical controls, coronary artery bypass grafting truly causes long-term neurocognitive deficit. Predictive variables for long-term neurocognitive deficit are neurocognitive deficit at 4-month follow-up, age, and persistent atrial fibrillation.

Neurocognitive deficit, defined as a combination of deficits in memory, learning, concentration and visual motor response, is an adverse event of coronary artery bypass grafting with an incidence of up to 80% perhaps the most common

Acknowledgements

We thank Daniela Dunkler, MS(Stat), for the statistical analysis of the work.

References (32)

  • J.M. Murkin et al.

    Long-term neurological, and neuropsychological outcome 3 years after coronary artery bypass surgery

    Anesth Analg

    (1996)
  • S.A. Nashef et al.

    European system for cardiac operative risk evaluation (EuroSCORE)

    Eur J Cardiothorac Surg

    (1999)
  • P. De Feo et al.

    Modest decrements in plasma glucose concentration cause early impairment in cognitive function and later activation of glucose counterregulation in the absence of hypoglycemic symptoms in normal man

    J Clin Invest

    (1988)
  • M. Grimm et al.

    Cyclosporine may affect improvement of cognitive brain function after successful cardiac transplantation

    Circulation

    (1996)
  • W. Engelhardt et al.

    P300-mapping–a neurophysiological tool to quantify cerebral dysfunction after coronary artery bypass grafting

    Eur J Cardiothorac Surg

    (1995)
  • K.A. Kiehl et al.

    Neuronal sources involved in auditory target detection and novelty processingan event related fMRI study

    Psychophysiology

    (2001)
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