Neurocognitive Disorders in Coronarian
Surgery and Place of the Mini Mental State Examination (MMSE)
Sandra Ait Aoudia* and Mohamed-Mohcen Sahraoui
Central Army Hospital, Algeria
Submission: September 23, 2017; Published: November 10, 2017
*Corresponding author: Sandra Ait Aoudia, Medical ICU, Central Army Hospital, Algiers, Algeria, Email: email@example.com
How to cite this article: Sandra Ait Aoudia, Mohamed-Mohcen Sahraoui. Neurocognitive Disorders in Coronarian Surgery and Place of the Mini Mental
State Examination (MMSE). J Anest & Inten Care Med. 2017; 4(2) : 555631. DOI:10.19080/JAICM.2017.04.555631
Introduction: Neurocognitive disorders after cardiac surgery are frequent and variable in their expression. In addition to perioperative stroke, cognitive impairment occurs in 30-70% of cases, most often functional and transient. They are detected on the clinic and by specific neuropsychic tests.
Patients and methods: Prospective study, including 37 patients operated on by coronary artery bypass graft surgery. The Mini Mental State Examination (MMSE) exploring cognitive functions was performed pre- and postoperatively (J3 post-op). The loss of 2 points or more suggests a neurocognitive disorder.
Results: Average age of our patients is 63 years ± 7.39 [44-74 years] with a sex ratio of 4.28 (30M/07W), post-operative: Calm awakening found in 67.56 % of our patients, agitation in 24.32%, temporo-spatial disorientation in 5.40% and ischemic stroke in 5.40% of patients.
Results of the MMSE: There are, memory impairment in 19 patients, calculation-Caution: 14 patients, orientation (time-space): 07 patients and praxia in 03 patients.
Discussion: The most affected population of neurocognitive disorders is in patients of advanced age (>60 years), stroke is found in 5.4% of cases and neurocognitive disorders in 57.57%, the most cognitive function often affected is memory. The factors favoring the onset of neurocognitive disorders are: Advanced age and duration of aortic clamping. The origin of neurocognitive disorders after coronary artery bypass graft surgery is multifactorial. In addition to patient-related factors, there are factors related to CEC and surgical procedure.
Conclusion: Neurocognitive complications after coronary artery surgery remain a worrying problem that could be aggravated given the increasing age of patients and the greater number of associated pathologies. The search for cognitive impairment should be an integral part of the pre- and post-operative evaluation of cardiac surgery patients. The Mini Mental State Examination (MMSE) would represent “the thermometer of cognitive function”.
Keywords: Coronary surgery; Neurocognitive disorders; Mini Mental State Examination (MMSE); Extracorporeal Circulation (ECC)
Neurocognitive disorders are the most frequent complication in cardiac surgery with extracorporeal circulation (CEC) . Their incidence varies from 30 to 70% according to the studies [2-6]. The existence of these postoperative neurocognitive dysfunctions has been a phenomenon known for many years, and so many studies have focused on perioperative periods of cardiac and vascular surgery. However, these dysfunctions have also been described during noncardiac surgeries and minor surgeries .
Progress in both anesthesia and surgery and CEC procedures has been accompanied by a reduction in morbidity and mortality that pushes age limits. Elderly patients with multiple pathologies benefiting more and more frequently from this type of surgery are the preferred target of postoperative neurocognitive disorders, the clinical consequences of which in terms of morbidity, mortality, postoperative rehabilitation  and the implications are far from negligible .
Morbidity and mortality in cardiac surgery is established through recognized specific scores such as Euroscore or Parsonnet score where only stroke, widely studied in cardiac surgery, is clearly taken into account as a postoperative neurological complication.
Roach et al. divided into 2 groups the neurological manifestations occurring after cardiac surgery:
Type I: includes stroke, TIA (Transient Ischemic Attack) and Comas. These are disorders of consciousness related to focal ischaemias of the cerebral parenchyma. Their incidence varies between 1.5 and 5.2% ;
Type II: represented by neuropsychological or cognitive
dysfunctions (confusion, agitation, disorientation, memory
disorders, ...), found in 30 to 70% of the patients operated
in cardiac surgery . They are, in most cases, functional
and transitory; without detectable organic lesion, detected
on the clinic and by specific neuropsychic tests.
Accurately encrypting the incidence of postoperative
cognitive dysfunction requires the use of easy-to-use, sensitive
and specific diagnostic tools. Many cognitive assessment
tests have been proposed to detect early symptoms reliably
and reliably. For example, the Mini Mental State Examination
(MMSE) has been validated specifically for the detection of
major disorders of major cognitive functions (orientation,
registration, attention and calculation, memory, language and
praxis) after cardiac surgery. Established in 1975 by Folstein
, it is an instrument for assessing the cognitive functions
developed for rapid screening. Its ease of use, speed of execution
(5-10mns) as well as the extensive functions explored quickly
imposed it amongst the brief evaluation instruments of functions
Some authors suggest discussing cognitive function
monitoring rather than establishing arbitrary criteria for
cognitive dysfunction  (Figure 1).
Our study included 37 adult patients operated for aortocoronary
bypass surgery. The exclusion criteria were: Combined
surgery (valve, carotid); neurological history (stroke, transient
ischemic cerebral accident, epilepsy, Parkinson, ...); Surgery with
heart beating and patients intubated more than 24h in postoperative.
The anesthetic protocol involved induction a classical
sequence associating hypnovel/etomidate or propofol,
sufentanil, rocuronium. The maintenance was provided by
isoflurane and/or a continuous infusion of propofol associated
with a continuous infusion of sufentanil. Patients were all
admitted to the intensive care unit where they received sedation
a few hours before waking and extubation. The evaluation of preand
post-operative cognitive functions involved the Mini Mental
State Examination. The test consisted of a series of questions
grouped into seven categories. These questions included:
orientation in time (5 points), orientation in space (5 points), immediate recall of three words (3 points), attention (5 points),
delayed recall three words (3 points), language (8 points) and
constructive praxis (1 point). The maximum possible score
was therefore 30 points . Patients were evaluated on the day
before surgery and on the third postoperative day. The pre- and
postoperative examiner was the same.
The statistical study carried out by Epi info 7 logicel. The
quantitative variables are expressed as mean +/- standard
deviations and compared using a reduced deviation test and
the qualitative variables are expressed in absolute values and in
percentages; the comparisons use the chi-square test.
The 37 patients operated for coronary surgery had an
average age of 63.46±7.39 (range: 44 and 74 years), a sex
ratio of 4.28 (30 H / 07 F). More than half of our patients were
obese with a history of hypertension, angina, dyslipidemia and
diabetes (Figure 2). For preoperative therapy, antiplatelet agents
are found in all our patients, Conversion enzyme inhibitors and
ß.blockers in more than 80% of our patients (Figure 3).
Of the 37 patients operated on for coronary surgery, only 33
patients were selected for our study, as 02 patients required a
ventilation time of> 24 h and 02 patients were never extubated
A postoperative decrease in the MMSE test was two or more
points in 19 patients (57.57%). The decline in performance
affected all items (Table 2). These patients were older (66.89
± 6.64 years) with the mean duration of longer aortic clamping
(98.72 ± 31.72mn) (Table 3).
Cardiac surgery (valvular or coronary) is a well documented
risk factor for postoperative cognitive disorders . The most
affected population concerns the oldest patients, benefiting from
the longest ECC. These data corroborate those of the literature
in this field [5,6,13]. The embolic mechanism is considered to
be the main provider of neurocognitive disorders during this
surgery, whereas cerebral hypoperfusion, in particular per-CEC,
or inflammation, probably play only a minor role. Microemboles
less than 40 μ in diameter composed of platelets, leukocyte
clusters, air, fat and particles from the CEC circuit [14-16] would
disrupt self-regulation of cerebral blood flow, making it more
sensitive to changes in mean arterial pressure . These debris
would be released at the time of aortic cannulation, clamping
and clamping, proximal suture of the venous graft and at each
aortic manipulation. These microemboli are easily visualized by
the transcranial doppler .
These phenomena of microembolism would be more
important in the case of valvular surgery than coronary surgery
. The aggravating role of too rapid warming after hypothermic
CEC and postoperative hyperthermia has been well documented.
Recent evidence suggests, however, that inflammation may favor
deterioration of cognitive performance after coronary bypass
In cardiac surgery where the embolic mechanism
remains predominant, materials to reduce the occurrence
of intraoperative stroke (arterial filters) have proved to be
ineffective. On the other hand, a not too rapid warming during
the use of a normothermic CEC, the postoperative temperature
control with the systematic use of antipyretics, the immediate
treatment or even the prevention of episodes of complete
arrhythmia by atrial fibrillation are all recommendations that
can be formulated .
For appropriate management of these patients, it is
interesting to create networks of care in partnership with
neuropsychologists, which will enable the development of
therapeutic strategies for the management of these patients. It
would be useful to create protocols to detect these perioperative
cognitive disorders (evaluation) and to propose a treatment
regimen according to the symptoms described.
While improvements in the morbidity and mortality of
cardiac surgery patients have been achieved through improved
surgical, anesthetic and resuscitation techniques, it remains
that 30% to 80% of these patients capable of developing
neurocognitive disorders that are mostly functional, transient
and of variable cause. These dysfunctions can sometimes persist
for months, even years and seem to be a factor of comorbidity.
Postoperative cognitive decline is associated with decreased
quality of life for patients and significant social and financial
implications for these patients and their families. It is important
to be able to assess the baseline cognitive status of these patients
before surgery. An easy-to-use, rapid, reproducible, and readily
available scale in patients’ beds, seems to us to be a wise option
to allow for a rapid, albeit rough, assessment of the cognitive
status of these patients. Prevention of post-operative cognitive
impairment requires the identification of individuals at risk and
must be one of the objectives of anesthesia consultation.
In total, the Mini Mental State Examination (MMSE) is a
practical tool for screening and clinical follow-up of the cognitive
state of patients by the clinician. Its simple use makes it a test
that deserves to be included in the systematic review of patients
operated in cardiac surgery. It is, however, only a test for