Blot, Stijn I.

Poelaert, Jan I.

Vandijck, Dominique M.

Elsevier - Publisher Connector 

Letters to the
Editor
CorCap device in addition to mitral
surgery in heart failure: Is it truly
beneficial?
To the Editor:
The recent report about mitral valve sur-
gery in heart failure1 raises a number of
interesting questions. While left ventricular
(LV) end-diastolic volume and end-systolic
volume in the treatment group decreased
significantly more with the cardiac support
device (CorCap; Acorn Cardiovascular, St
Paul, Minn) than in the control group, other
differences were statistically insignificant.
Important end points such as survival, ejec-
tion fraction, and measurable indices of
functional capacity (6-minute walking test
and oxygen consumption), although pre-
sented as “better” in the treatment group,
were not statistically different. The only
adverse event that was nearing significance
(P  .06) in favor of the control group,
namely a neurologic deficit/stroke, is hid-
den in Table 2. The lack of significant
advantages to the treatment group in the
presence of a similarly stable mitral repair
is intriguing. The CorCap device is envel-
oping both ventricles, defining a new upper
limit to total (end-diastolic) biventricular
volume. We are all familiar with the echo-
cardiographic picture of the spherical shape
of the globally enlarged LV, including the
interventricular septum. Obviously, by en-
veloping both ventricles from the outside,
the device does not restrict or reshape the
septal component of LV dilatation. More-
over, assuming that the tension of the de-
vice is even and equal throughout, this
means that we are expecting to limit LV
free-wall dilatation by suspending it on the
right ventricle (RV). Can we trust the RV
with its much lower pressures and wall
tension to successfully counteract and re-
strict either the systolic or the diastolic
distention of the globally or even the re-
gionally enlarged LV? It is likely that the
greater reduction in LV volumes observed
in the treatment group is the result of a new
balance between the two ventricles. RV
volume is restricted more than LV volume.
The RV being dragged or “squeezed” to-
ward the LV during each systole, and
having decreased space for diastolic fill-
ing because of the rightward bulging, non-
compliant ventricular septum, can now
produce a smaller stroke volume. LV
end-diastolic volume is consequently de-
creased, with some improvement in shape,
but probably with minimal change in wall
stress and ejection fraction beyond what
has already been accomplished with mitral
repair or replacement. The authors con-
clude that in addition to the clear benefit
from elimination of mitral regurgitation,
there is significant additional benefit with
the CorCap device.
The question remains whether the me-
chanical preload reduction of the LV via
RV restriction, which does not improve LV
contractile function, outweighs the adverse
events and the risks and technical difficul-
ties encountered when such a patient re-
quires heart transplantation.
Amir Elami, MD
Department of Cardiothoracic Surgery
Hadassah University Hospital
Jerusalem, Israel
Reference
1. Acker MA, Bolling S, Shemin R, Kirklin J,
Oh JK, Mann DL, et al. Mitral valve surgery
in heart failure: insights from the Acorn Clin-
ical Trial. J Thorac Cardiovasc Surg. 2006;
132:568-77.
doi:10.1016/j.jtcvs.2006.09.058
Microbiologically documented
nosocomial infections after coronary
artery bypass surgery without
cardiopulmonary bypass
To the Editor:
In the latest issue of the Journal of Tho-
racic and Cardiovascular Surgery, we read
with great interest the article by Falagas
and colleagues,1 in which they evaluated
the frequency, characteristics, and predis-
posing factors of microbiologically docu-
mented nosocomial infections in a well-
defined subgroup of critically ill patients
undergoing off-pump coronary artery bypass
grafting. In this clearly and well-documented
The Editor welcomes submissions for
possible publication in the Letters to the
Editor section that consist of commen-
tary on an article published in the Jour-
nal or other relevant issues. Authors
should:
● Include no more than 500 words of text,
three authors, and five references
● Type with double-spacing
● See http://jtcs.ctsnetjournals.org/misc/
ifora.shtml for detailed submission
instructions.
● Submit the letter electronically via
jtcvs.editorialmanager.com.
Letters commenting on an article pub-
lished in the JTCVS will be considered if
they are received within 6 weeks of the
time the article was published. Authors
of the article being commented on will be
given an opportunity to offer a timely
response (2 weeks) to the letter. Authors
of letters will be notified that the letter
has been received. Unpublished letters
cannot be returned.
590 The Journal of Thoracic and Cardiovascular Surgery ● February 2007
article, it is mentioned that there is a sta-
tistically significant difference, in terms of
mortality, between patients having a docu-
mented infection and the rest of the patients
(23.8% vs 1.2%, P  .001).1 These data,
however, should be interpreted with cau-
tion. When considering the main character-
istics of the study cohort, patients with
infection versus patients without infection
already differ in terms of age and underly-
ing conditions before the onset of infection.
The authors themselves demonstrated clearly
a statistically significant difference con-
cerning left ventricular ejection fraction
(better in the patient group with lower mor-
tality). This cannot be neglected because it
has widely been demonstrated that such
organ dysfunctions are indispensably asso-
ciated with increased mortality.2 Here a
logistic regression model with adjustment
for possible confounding factors, such as
length of hospitalization before infection,
age, and severity of illness, could be used
to assess the potential causative effect of
infection on mortality. With regard to this,
we wonder whether the authors can provide
further details on the rate of patients receiv-
ing appropriate antimicrobial agents. This
has been shown to significantly improve
patient outcome.3-5 Furthermore, with re-
spect to the severity of illness, a certain
estimation by means of, for example,
EuroSCORE could explain possible differ-
ences of outcome measures between both
groups. We would appreciate if Falagas
and colleagues could elaborate on their re-
port, keeping those issues in mind.
Dominique M. Vandijck, RN, MSc, MAa,b
Stijn I. Blot, RN, MSc, PhDa,b
Jan I. Poelaert, MD, PhDa
Department of Intensive Care Medicinea
Ghent University Hospital
Ghent, Belgium
Healthcare Departmentb
Hogeschool Ghent, “Vesalius”
Ghent, Belgium
References
1. Falagas ME, Rosmarakis ES, Rellos K, Micha-
lopoulos A, Samonis G, Prapas SN. Microbio-
logically documented nosocomial infections
after coronary artery bypass surgery without
cardiopulmonary bypass. J Thorac Cardiovasc
Surg. 2006;132:481-90.
2. Blot SI, Depuydt P, Annemans L, et al. Clinical
and economic outcomes in critically ill patients
with nosocomial catheter-related bloodstream
infections. Clin Infect Dis. 2005;41:1591-8.
3. Blot S, Vandewoude K. Early detection of sys-
temic infections. Acta Clin Belg. 2004;59:20-3.
4. Colardyn F. Appropriate and timely empirical
antimicrobial treatment of ICU infections—a
role for carbapenems. Acta Clin Belg. 2005;
60:51-62.
5. Kollef M. Appropriate empirical antibacterial
therapy for nosocomial infections: getting it
right the first time. Drugs. 2003;63:2157-68.
doi:10.1016/j.jtcvs.2006.09.044
Reply to the Editor:
We appreciate the comments of Vandijck
and colleagues regarding our study.1 They
raised the issue of the potential mortality
attributable to infection in our study group
(patients who underwent off-pump coronary
artery bypass grafting). They consider that
confounding factors, such as age, comorbid-
ity, left ventricular ejection fraction, antimi-
crobial treatment, and EuroSCORE values,
might have led to the observed statistically
significant difference in mortality between
patients with and without microbiologically
documented nosocomial infection.
Our results regarding mortality of patients
who underwent coronary artery bypass graft-
ing are in accordance with the results of pre-
vious studies (a fact that is mentioned in the
discussion section of our article).2,3 For ex-
ample, using data from the US Society of
Thoracic Surgeons National Cardiac Data-
base, Fowler and associates2 showed that pa-
tients with major infection had significantly
higher mortality (17.3% vs 3.0%, P .0001)
and postoperative length of stay of longer
than 14 days (47.0% vs 5.9%, P  .0001)
than patients without infection.
However, we agree with Vandijck and
colleagues that infections are sometimes the
consequence of other postoperative compli-
cations or comorbidity that predispose to in-
fections. It should be emphasized that the
majority of patients (4/7 [57%]) with sternal
wound infection in our cohort had a history
of previous sternotomy or postoperative in-
vasive interventions at the surgical site.
We did not collect data to estimate
EuroSCORE values for the group of patients
who did not have nosocomial infection based
on the design of our study, and these data are
not readily available now to be analyzed.
However, we performed an additional analy-
sis of factors associated with mortality in our
cohort of patients. Variables that were statis-
tically associated (P  .05) with mortality in
the bivariable analysis were entered in a
backward, stepwise, multivariable logistic re-
gression model. This statistical analysis re-
vealed that independent risk factors for death
were urgent operation, anemia (hematocrit,
34%), and low left ventricular ejection
fraction on admission (P .001 for all these
variables).
We also agree with Vandijck and col-
leagues that appropriate antimicrobial
treatment of postoperative infections is es-
sential to improve patient outcome. It has
been shown that inappropriate empirical
therapy is associated with increased mor-
tality, especially among patients with in-
fections caused by multidrug-resistant
bacteria.4 In fact, old antibiotics, such as
polymyxins, have been used recently to
combat some of these infections.5 Two of
21 patients with infection in our cohort
(patients 2 and 17 in Table 3 of our article)1
were infected with multidrug-resistant iso-
lates; these patients did not receive appropri-
ate empirical antimicrobial therapy until the
results of the in vitro susceptibility testing of
the isolated pathogens became available.
Matthew E. Falagas, MD, DSca,b,c
Evangelos S. Rosmarakis, MDa
Sotirios N. Prapas, MDd
Alfa Institute of Biomedical Sciences (AIBS)a
Athens, Greece
Department of Medicineb
Department of Cardiac Surgeryd
Henry Dunant Hospital
Athens, Greece
Department of Medicinec
Tufts University School of Medicine
Boston, Mass
References
1. Falagas ME, Rosmarakis ES, Rellos K,
Michalopoulos A, Samonis G, Prapas SN.
Microbiologically documented nosocomial
infections after coronary artery bypass sur-
gery without cardiopulmonary bypass. J Tho-
rac Cardiovasc Surg. 2006;132:481-90.
2. Fowler VG Jr, O’Brien SM, Muhlbaier LH,
Corey GR, Ferguson TB, Peterson ED. Clinical
predictors of major infections after cardiac sur-
gery. Circulation. 2005;112(suppl):I358-65.
3. Kollef MH, Sharpless L, Vlasnik J, Pasque C,
Murphy D, Fraser VJ. The impact of nosoco-
mial infections on patient outcomes following
cardiac surgery. Chest. 1997;112:666-75.
4. Falagas ME, Kasiakou SK, Rafailidis PI,
Zouglakis G, Morfou P. Comparison of mor-
tality of patients with Acinetobacter bauman-
nii bacteraemia receiving appropriate and in-
appropriate empirical therapy. J Antimicrob
Chemother. 2006;57:1251-4.
5. Falagas ME, Michalopoulos A. Polymyxins:
old antibiotics are back. Lancet. 2006;367:
633-4.
doi:10.1016/j.jtcvs.2006.10.013
Letters to the Editor
The Journal of Thoracic and Cardiovascular Surgery ● Volume 133, Number 2 591


Microbiologically documented nosocomial infections after coronary artery bypass surgery without cardiopulmonary bypass 

Vandijck, Dominique

Blot, Stijn

Poelaert, Jan

Ghent University Academic Bibliography

Microbiologically documented nosocomial infections after coronary artery bypass surgery without cardiopulmonary bypass

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Microbiologically documented nosocomial infections after coronary artery bypass surgery without cardiopulmonary bypass

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