Journal of Alzheimer’s Disease 42 (2014) S45–S51 DOI 10.3233/JAD-132540 IOS Press
S45
Does Preoperative Mild Cognitive Impairment Predict Postoperative Cognitive Dysfunction after On-Pump Coronary Bypass Surgery? Olga A. Trubnikovaa,∗ , Anastasia S. Mamontovaa , Irina D. Syrovaa , Olga V. Malevaa and Olga L. Barbarashb a Department
of Polyvascular Atherosclerosis, Research Institute for Complex Issues of Cardiovascular Diseases, Russian Academy of Medical Sciences, Kemerovo, Russian Federation b Director of Research Institute for Complex Issues of Cardiovascular Diseases, Russian Academy of Medical Sciences, Kemerovo, Russian Federation
Accepted 3 April 2014
Abstract. Background: Mild cognitive impairment (MCI) may contribute to the development of postoperative cognitive dysfunction (POCD) after coronary artery bypass grafting (CABG). Objective: The aim of this study was to investigate the incidence of early and long-term POCD after CABG in coronary heart disease patients with and without preoperative MCI. Methods: The study enrolled two groups of males with coronary heart disease: 51 without MCI (mean age 56.0 ± 6.42 years) and 50 with MCI (mean age 56.4 ± 5.55 years). Baseline clinical characteristics as well as durations of cardiopulmonary bypass and aortic cross-clamping were similar between the two groups. MCI was defined as a Mini–Mental State Examination score of less than 28. All patients underwent detailed neuropsychological examinations (12 tests) before and 7–10 days and 1 year after surgery. The incidence of early and long-term POCD was estimated on the basis of criteria defined as a 20% decline on 20% of the tests. Results: Early POCD was diagnosed in 72% of cases in patients with MCI and in 79% of those without MCI (p = 0.5; odds ratio [OR] = 0.68; 95% confidence interval [CI] 0.2–2.2). Long-term POCD was diagnosed in 72% of MCI patients and in 70% of non-MCI patients (p = 0.8); OR = 1.08 (95% CI 0.4–2.9). Conclusions: Our results show that the presence of MCI is not the leading cause of either early or long-term POCD in patients undergoing CABG. Further research should focus on the contribution of important clinical factors, including progression of atherosclerosis and adherence, to post-CABG POCD. Keywords: Cognition disorders, coronary artery bypass grafting, mild cognitive impairment, postoperative complication
∗ Correspondence to: Olga A. Trubnikova, PhD, Research Institute for Complex Issues of Cardiovascular Diseases, Russian Academy of Medical Sciences, Siberian Branch, Department of Polyvascular Atherosclerosis, Laboratory of Neurovascular Pathology, Boulevard Sosnovyi, 6; Kemerovo 650002, Russian Federation. Tel./Fax: +7 3842643153; E-mail: [email protected].
ISSN 1387-2877/14/$27.50 © 2014 – IOS Press and the authors. All rights reserved
S46
O.A. Trubnikova et al. / Cognitive Impairment after CABG
INTRODUCTION Postoperative cognitive dysfunction (POCD) has recently been reported to be a common complication following cardiovascular surgery [1, 2]. POCD is known to reduce the efficacy of a surgical procedure, significantly affecting patients’ quality of life and their compliance with long-term therapy, thereby worsening the disease prognosis [3, 4]. Several studies have suggested that age and duration of cardiopulmonary bypass (CPB) as well as preoperative status of the patient affect the incidence and severity of POCD [5–7]. However, pre-dementia cognitive disorders, including mild cognitive impairment (MCI), are among those preoperative factors that contribute to the development of POCD but have not been thoroughly studied. A common opinion in the medical literature is that a cohort of patients referred for coronary artery bypass grafting (CABG) appears to be middle-aged and elderly individuals presenting with severe coronary lesions and possible cognitive impairment [8]. Vascular lesions play an important role in the pathogenesis of MCI [9, 10]. The severity of coronary atherosclerosis has been shown to correlate directly with the severity of atherosclerotic lesions of the cerebral vessels [11]. MCI patients scheduled for CABG are expected to be at risk for POCD because of already existing pathological structural changes in the brain. The aim of the study was to assess the incidence of and determine risk factors for early and long-term POCD in patients with and without MCI who have undergone on-pump coronary revascularization.
MATERIALS AND METHODS The study design was approved by the local ethics committee of the research institute. All patients enrolled in the study provided informed consent. One hundred and one males were enrolled in the study. The inclusion criteria were as follows: age 45–69 years, on-pump CABG, male patients. The exclusion criteria were as follows: age ≥70 years, carotid artery stenosis ≤50%, severe rhythm disorders, chronic heart failure type IIB, diabetes mellitus, chronic obstructive pulmonary disease, oncopathologic diseases, central nervous system diseases, traumatic brain injury, transient ischemic attack, lacunar infarcts imaged with magnetic resonance imaging (MRI), a Mini-Mental State Examination (MMSE) score
S45
Does Preoperative Mild Cognitive Impairment Predict Postoperative Cognitive Dysfunction after On-Pump Coronary Bypass Surgery? Olga A. Trubnikovaa,∗ , Anastasia S. Mamontovaa , Irina D. Syrovaa , Olga V. Malevaa and Olga L. Barbarashb a Department
of Polyvascular Atherosclerosis, Research Institute for Complex Issues of Cardiovascular Diseases, Russian Academy of Medical Sciences, Kemerovo, Russian Federation b Director of Research Institute for Complex Issues of Cardiovascular Diseases, Russian Academy of Medical Sciences, Kemerovo, Russian Federation
Accepted 3 April 2014
Abstract. Background: Mild cognitive impairment (MCI) may contribute to the development of postoperative cognitive dysfunction (POCD) after coronary artery bypass grafting (CABG). Objective: The aim of this study was to investigate the incidence of early and long-term POCD after CABG in coronary heart disease patients with and without preoperative MCI. Methods: The study enrolled two groups of males with coronary heart disease: 51 without MCI (mean age 56.0 ± 6.42 years) and 50 with MCI (mean age 56.4 ± 5.55 years). Baseline clinical characteristics as well as durations of cardiopulmonary bypass and aortic cross-clamping were similar between the two groups. MCI was defined as a Mini–Mental State Examination score of less than 28. All patients underwent detailed neuropsychological examinations (12 tests) before and 7–10 days and 1 year after surgery. The incidence of early and long-term POCD was estimated on the basis of criteria defined as a 20% decline on 20% of the tests. Results: Early POCD was diagnosed in 72% of cases in patients with MCI and in 79% of those without MCI (p = 0.5; odds ratio [OR] = 0.68; 95% confidence interval [CI] 0.2–2.2). Long-term POCD was diagnosed in 72% of MCI patients and in 70% of non-MCI patients (p = 0.8); OR = 1.08 (95% CI 0.4–2.9). Conclusions: Our results show that the presence of MCI is not the leading cause of either early or long-term POCD in patients undergoing CABG. Further research should focus on the contribution of important clinical factors, including progression of atherosclerosis and adherence, to post-CABG POCD. Keywords: Cognition disorders, coronary artery bypass grafting, mild cognitive impairment, postoperative complication
∗ Correspondence to: Olga A. Trubnikova, PhD, Research Institute for Complex Issues of Cardiovascular Diseases, Russian Academy of Medical Sciences, Siberian Branch, Department of Polyvascular Atherosclerosis, Laboratory of Neurovascular Pathology, Boulevard Sosnovyi, 6; Kemerovo 650002, Russian Federation. Tel./Fax: +7 3842643153; E-mail: [email protected].
ISSN 1387-2877/14/$27.50 © 2014 – IOS Press and the authors. All rights reserved
S46
O.A. Trubnikova et al. / Cognitive Impairment after CABG
INTRODUCTION Postoperative cognitive dysfunction (POCD) has recently been reported to be a common complication following cardiovascular surgery [1, 2]. POCD is known to reduce the efficacy of a surgical procedure, significantly affecting patients’ quality of life and their compliance with long-term therapy, thereby worsening the disease prognosis [3, 4]. Several studies have suggested that age and duration of cardiopulmonary bypass (CPB) as well as preoperative status of the patient affect the incidence and severity of POCD [5–7]. However, pre-dementia cognitive disorders, including mild cognitive impairment (MCI), are among those preoperative factors that contribute to the development of POCD but have not been thoroughly studied. A common opinion in the medical literature is that a cohort of patients referred for coronary artery bypass grafting (CABG) appears to be middle-aged and elderly individuals presenting with severe coronary lesions and possible cognitive impairment [8]. Vascular lesions play an important role in the pathogenesis of MCI [9, 10]. The severity of coronary atherosclerosis has been shown to correlate directly with the severity of atherosclerotic lesions of the cerebral vessels [11]. MCI patients scheduled for CABG are expected to be at risk for POCD because of already existing pathological structural changes in the brain. The aim of the study was to assess the incidence of and determine risk factors for early and long-term POCD in patients with and without MCI who have undergone on-pump coronary revascularization.
MATERIALS AND METHODS The study design was approved by the local ethics committee of the research institute. All patients enrolled in the study provided informed consent. One hundred and one males were enrolled in the study. The inclusion criteria were as follows: age 45–69 years, on-pump CABG, male patients. The exclusion criteria were as follows: age ≥70 years, carotid artery stenosis ≤50%, severe rhythm disorders, chronic heart failure type IIB, diabetes mellitus, chronic obstructive pulmonary disease, oncopathologic diseases, central nervous system diseases, traumatic brain injury, transient ischemic attack, lacunar infarcts imaged with magnetic resonance imaging (MRI), a Mini-Mental State Examination (MMSE) score
