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Is the risk of Delirium reduced in Minimal
Invasive Cardiac Surgery
Chaud Germán J1*, Simon M Belén2, Filippa Pablo A1, Gavotti G Carolina2, Ferreyra Lilian2, Flores Marcela2, Paladini Guillermo1 and Martinez Colombres M Alejandro1
1 Department of Cardiac Surgery, Hospital Privado Universitario de Córdoba, Instituto Universitario de Ciencias Biomédicas de Córdoba, Argentina
2 Department of Psychiatric, Hospital Privado Universitario de Córdoba, Instituto Universitario de Ciencias Biomédicas de Córdoba, Argentina
Submission: May 07, 2019; Published: June 19, 2019
*Corresponding author: Germán J Chaud, Hospital Privado Centro Médico de Córdoba, Naciones Unidas 346, (5016) Córdoba, Argentina
How to cite this article:Chaud G J, Simon M B, Filippa P A, Gavotti G C, Ferreyra L, et al. Is the risk of Delirium reduced in Minimal Invasive Cardiac Surgery. J
Cardiol & Cardiovasc Ther. 2019; 14(1): 555879. DOI: 10.19080/JOCCT.2019.14.555879
Background: The number of cardiac operations is steadily increasing in industrialized countries, being Delirium one of the most frequent postoperative complications. Aortic Valve Replacement by mini-invasive surgery has reported to offer innumerable benefits over Complete Sternotomy, such as better esthetic, less surgical trauma, pain, blood and postoperative complications, a functional recovery and a shorter hospital stay.
Objectives: To determine the frequency of Delirium and to identify its risk factors in patients undergoing mini-sternotomy (MS) versus full sternotomy (FS) isolated aortic valve replacement (AVR).
Methods: An interdisciplinary, descriptive and retrospective study of 113 adults patients who underwent an Isolated Aortic Valve Replacement (AVR) with mini-sternotomy (MS) and full sternotomy (FS) was conducted. Variables related to delirium were characterized as being present before, during or after cardiac surgery.
Results: Delirium occurred in 26 patients (23%). In the MS group, 12 patients (25%) had Delirium while 36 (75%) had no Delirium. In the FS group, 14 (21.5%) patients had Delirium whereas 51 did not have it (78.5%) and P: 0.66. Regarding to valve type among Delirium patients, 5 had a mechanical one while 21 patients with a biological valve. P: 0.02. Late extubation had 7 (6.2%) patients in the Delirium group versus 1 (9%) in the non-Delirium group. P: 0.001. Postoperative Hb analysis revealed an average of 9.2mg/dL and 9.8mg/dl for Delirium and non - Delirum patients respectively. P: 0.05. Renal disease was showed in 8 (7.1%) patients in the Delirium group versus 4 in the No delirium group (3.5%) with a P value of 0.001. No mortality event has been registered in any of the groups.
Conclusion: MS has shown numerous advantages over conventional surgery before this study, nevertheless the risk of Delirium has not been previously assessed in this context. The risk factors and an increasing frequency of Delirium should be taking into account due to its high morbidity rate and significant cost of the health system.
The rapid aging of the population has led to the appearance of a new type of surgical patient different from the traditional one, with the coexistence of different chronic diseases, numerous drugs and less functional reserve. That situation makes it more susceptible in stress situations to develop perioperative complications such as Delirium or Confusional Syndrome .
Besides, the number of cardiac operations is steadily increasing in industrialized countries, being Delirium one of the
most frequent postoperative complications with an incidence varying from 3% to 52%. Postoperative delirium is usually transient and can be resolved spontaneously, but in some cases it is associated with a large number of serious complications such as cognitive and functional impairment, prolonged hospital stay and an increased mortality and morbidity. The cause of post–cardiac surgery delirium is unknown and is probably multifactorial in origin. Valve Counting Procedures such as Aortic Valve Replacement as well as those combined with extracorporeal circulation have demonstrated higher rates of Delirium compared
to non-cardiopulmonary bypass. In addition, other independent
predictors have been strongly related to Delirium, such as
advanced age, history of Cerebrovascular Disease (OR 2.15),
Diabetes (OR 1.30), peripheral vascular disease (OR 1.34), atrial
fibrillation (OR 1.35), alcohol use(OR 6.11), low ejection fraction
(OR 1.30), high requirement for blood transfusions (OR 3.12),
prolonged intubation time (OR 1.20), and prolonged stay in
intensive care units (OR 1.11) [2-5]. Gottesman and colleagues
showed that delirium following cardiac surgery is an independent
predictor of death after 10 years postoperatively .
Regarding to the surgical technique, Aortic Valve Replacement
by mini-invasive surgery has reported to offer innumerable
benefits over Complete Sternotomy, such as better esthetic, less
surgical trauma, pain, blood and postoperative complications, a
functional recovery and a shorter hospital stay [7-9].
The possibility that Postoperative Delirium may be modifiable
makes it an attractive target to identify its risk factors, and with
that, improve the quality of care in cardiac surgical patients.
This study represents the first investigation ever made
comparing specifically Delirium on different approach techniques.
An interdisciplinary, descriptive and retrospective study
of adults patients admitted to perform an Isolated Aortic Valve
Replacement (AVR) at Hospital Privado Universitario de Córdoba
in the period from January 1, 2011 to December 31, 2015 was
conducted (n = 113).
An interdisciplinary, descriptive and retrospective study
was conducted. The inclusion criteria included adults between
25 and 85 years of age who underwent an Isolated Aortic Valve
Replacement (AVR) with mini-sternotomy or full sternotomy
(FS).The selection of the type of surgery depended of the
surgeon’s preference were excluded all patients with Aortic Valve
Replacement combined with Coronary surgery, Mitral Valve or
Ascending aorta replacement, pediatric patients, those who died
within 48 hours of surgery prior to being extubated and patients
with story of Infective Endocarditic, prolonged hospital stay
and Delirium during the same hospitalization that the surgical
procedure was developed.
The data were extracted from the electronic medical record
recorded in tables characterizing the variables as being present
before, during or after cardiac surgery, and analyzed using the
statistical software IBM® SPSS Statics Version 19. To compare
categorical variables was utilized Chi2 test or fisher’s exact test as
appropriate. A P value less than 0.05 was considered statistically
significant. Continuous variables with a normal distribution were
compared with T-test and for those with non-Gaussian distribution
variables the Mann-Whitney U-test was used (Tables 1-3).
A search in different databases (pubmed, science direct,
Scopus) was performed with the following key words or mesh
terms: Delirium, minimally invasive, cardiac surgery, aortic valve
replacement, Adults in order to identify previous work related to
Delirium and minimally invasive cardiac surgery (Tables 4-6).
In all patients, central cannulation for extracorporeal
circulation was performed. Myocardial protection consisted of
antegrade and retrograde administration of blood cardioplegia.
Standard techniques were used to remove the native aortic
valve, decalcify the aortic ring and insert the new prosthesis. The
same technique of L-ministernotomies was also used up to the 4
intercostal space in all patients.
Variables were select using universal definitions and according
to Society of Thoracic Surgery National Database specifications:
• Delirium is an acute confusional state with a fluctuating
course, characterized by a disturbance in attention and awareness.
This is accompanied by a change in memory, disorientation,
alteration in language, or perceptual distortion or a perceptualmotor
• Late extubation is defined as the cessation of assisted
mechanical ventilation after the first 8 postoperative hours.
History of Psyquiatric Disease such as Mood Disorder,
Cognitive Impairment Psychotic disorder previous psychiatric
medication as anxiolytics, anti dementials, antidepressants and
antipsychotics). History of consumption of toxic substances
consisted in the use and abuse of licit and illicit drugs as cocaine,
marijuana and alcohol. Reintervention was described as the
performance of a new surgical procedure after the main surgery
during the same hospitalization. Conversion was defined as the
development of a full-sternotomy during the same procedure
in which mini-sternotomy was previously performed. These
were analyzed in the CD group. Complication was defined as
the diagnosis of pneumonia, pleural effusion, tracheobronchitis,
surgical site infection, urinary infection and pericarditis made
after the procedure.
All identified Delirium cases were retrospectively reviewed by
professionals from the Psychiatry Service.
The analysis included 126 patients, 13 of whom were excluded
due to: 9 for Infective Endocarditis, 1 patient older than 85 years
old, 1 younger than 25 years of age, 1 presented prolonged hospitalization with delirium prior to surgery and 1 died in the
immediate postoperative period before extubation.
The final sample consisted in 113 patients, 67 of who were
male and 46 females. The mean age was 66 ± 11 (ą SD) with a
range of 25-83 years separated in 2 groups according to their
age in over 70 or under 69 years old. Regarding to the number
of surgeries, 48 MS (42.5%) and 65 FS (57.5%) were performed.
Of the total ME, only 2 required FS conversion and the same
were analyzed in the FS group. Delirium occurred in 26 patients
(23%). In the MS group, 12 patients (25%) had Delirium while 36
(75%) had no Delirium. In the FS group, 14 (21.5%) patients had
Delirium whereas 51 did not have it (78.5%) and P: 0.66.
The data were analyzed and grouped in preoperative
demographic variables, in which no statistically significant
differences were found.
We analyzed the same variables separated in 2 groups
Delirium and No Delirium. It showed a significant difference in
age in which mean of 64.4 years for No delirium Vs 72.6 years
for the Delirium group (P: 0.001) were obtained. The variables
history of Renal Insufficiency and Psychiatric medication showed
The intraoperative variables analysis showed that, of the
26 patients with Delirium, 5 had a mechanical valve and 21 had
biological valve with a significant P. P 0.02. Re-intervention was
evidenced in 2 patients of each group. P: 0.47. CPB duration had
a mean of 95.15 minutes for patients with Delirium Vs 100.31
minutes for those without it. P: 0.13. Cross- clamp time did not
show significant differences showing an average of 72.15 vs 79.86
minutes for Delirium and No delirium patients respectively P:
The analysis of postoperative demographic variables did
not show significant differences, but they were homogeneous.
However, it was observed that the late extubation was developed
in 7 patients in the delirium group and in 1of the Non delirium
group P: <0.001. Thus, 9 in the delirium group (8%) and 24 in
the non-delirium group (21.2%) P: 0.49 were also found in the
variable fever. Atrial fibrillation was present in 11 in the first
group (9.7%) and 19 in the second group (16.8%) P: 0.038.
Duration hospitalization stay has been assessed as a
complication of Delirium due to in the No delirium group the
mean of days was 6.24 and, in the Delirium, group was 11.9 (P:
0.001). On the other hand, the duration of Coronary Unit stay
was 2.8 days in the group No delirium Vs 7.2 days in the Delirium
group (P: 0.001) (Figure 1).
The benefit of MS in comparison to FS has been demonstrated
in terms of shorter hospital stay, shorter postoperative ventilation
time and reduced transfusion requirements associated with
longer CPB and clamping times secondary to technical difficulties
due to lower exposure. However, these variables have never been
evaluated in the context of a patient with delirium .
Cohn and Schmitto have studied and demonstrated the
benefits of MICS by valuing different variables such as aesthetic
effect, neurological events, bleeding, transfusions and the need for
reoperation considering pain, quality of life and recovery to finally
assess hospital stay and costs .
Tatsuya Yamada et al. assessed the risk of Delirium in MICS
vs FS in 2003  Merk et al. demonstrated an increased risk
of Delirium in MICS . However, none of the them considered
the implication of this in different complications such as
hospitalization stay and mortality. Leslie et al. compared surgery vs
TAVI in octagenaria demonstrating a higher incidence of Delirium
in FS but it did not clarify if they performed MICS previously .
In our series, we did not find statistically significant differences
in the risk of Delirium in those patients who underwent MS
(12/26) vs FS (14/26) P: 0. Regarding to age, it had been showed
a significant difference in favor of Delirium in patients older than
70 years. That fact has a direct relation with the type of valvular
prosthesis used where we see a relationship between Delirium
and the biological valves p: 0.02. The analysis of the postoperative
variables showed that those patients with lower postoperative Hb
had more Delirium, however, their direct relationship with MS was
not demonstrated, which, despite not having significant results,
showed better postoperative Hb results compared to FS. This is
directly related to what Dra. Koster has already demonstrated
The postoperative renal function failure revealed a significant
result in favor of Delirium with a P: 0.001 showing no direct
relationship with the performance of MS. The analysis of CPB
and clamping times did not reveal significant results, however
they had a slight tendency to be higher in patients who had
Delirium CPB : 100.31 vs 95.15 min. Clamp 79.86 vs 72.15 min
respectively P: 0.13 which was also reflected in the analysis of MS
Vs FS, CEC: 104.8 min vs 94.93 min clamp: 81.35 min vs 75.68 min
respectively. Thus, patients with late extubation had significant
differences in favor of delirium 7 (6.2%) vs 1 (9%) of the nondelirium
group. P: 0.001.
We also took into account the complications of Delirium such
as the duration of hospitalization stay the inpatient care area and coronary unit. Its analysis showed that all the patients who
suffered Delirium had statistically significant differences in the
days of hospitalization in the inpatient care area and in coronary
unit, 11.9 vs 6.24 days and 7.2 vs 2.8 days, respectively (P: 0.001).
That result agrees with Dr. Brown et al. publication about Delirium
after cardiac surgery . This fact demonstrate that Delirium is
a potential complication in patients undergoing postoperative
cardiac surgery care not only increasing their morbidity but also
increasing greatly health costs as estimated by Gottesman 38
trillion to 152 trillion dollars per year .
No mortality events have been registered in any of the groups.
Nevertheless, it has been shown a survival improvement survival
with MS .
Finally, we deduce from the multivariate analysis that the
most important risk factors for the development of delirium
regardless the approach technique, are age over 70 years with OR.
4.98 = 0.037 and renal insufficiency with OR. 10.38 P 0.002. This
accords with the results obtained by Kurt Bestehorn associating
these risk factors. However, we might disagree with the mortality
risk duet to it has not been recorded events in our study, which is
probably related to the low number of patients we enrolled .
This investigation does not find any direct relation between
delirium and MS, despite this has been identified in patients older
than 70 years regardless of the surgical approach, we believe it is
necessary to carry out a prospective study with a larger number
of patients such as the one we are currently performing at our
center in order to confirm the previous findings and implement
a Delirium risk checklist as demonstrated in his paper Koster et
MS has shown numerous advantages over conventional
surgery before this study, nevertheless the risk of Delirium has
not been previously assessed in this context. The risk factors and
an increasing frequency of Delirium should be taking into account
due to its high morbidity rate and significant cost of the health
Further, investigations comparing MS with last generations
valves will be important before determine whether a patient over
70 years can undergo an AVR with MICS.
Prof. Dr. Domingo Balderramo. Statistical Analyst. Hospital
Privado Universitario de Córdoba (Institute of Biomedical
Sciences of Córdoba) Physician Florence Becerra. Statistical
Analyst. University Hospital of Cordoba.
The main limitation of our study is being retrospective and
belonging to a single center, therefore we tried to analyze a
large number of variables. The fact of being unicentric gives the
opportunity and concern of future analyzes in a prospective way
in order to confirm or refute this theory in a more reliable way.
Although with a low number of patients, this study represents
the first analysis of Delirium comparing MICS vs FS.
All patients were retrospectively evaluated by psychiatric
specialists. This design of `patient assessment makes it possible
for patients with hypoactive delirium to be obviated or dismissed.