Anesthesiology 2003; 98:823–9 © 2003 American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins, Inc.
The Importance of Prior Stroke for the Adjusted Risk
of Neurologic Injury after Cardiac Surgery for Women
and Men
Charles W. Hogue, Jr., M.D.,* Charl J. De Wet, M.B.Ch.B.,† Kenneth B. Schechtman, Ph.D.,‡
Victor G. Dávila-Román, M.D.§
Background: Women are at higher risk for stroke after car-
diac surgery than men. Prior analysis of risk profiles for peri-
operative stroke that have mostly combined data from women
and men may fail to identify gender-specific risks. The purpose
of this study was to evaluate whether patient gender impacts
adjusted risk for stroke after cardiac surgery.
Methods: Demographic and perioperative data were prospec-
tively collected from 2,972 patients undergoing cardiac surgery.
Carotid artery ultrasound examination was performed before
surgery for patients aged 65 yr or older or when there was a
history of transient ischemic attacks or prior stroke. Epiaortic
ultrasound was performed at the time of surgery in all patients
to assess for atherosclerosis of the ascending aorta.
Results: Strokes occurred after surgery in 30 women and 18
men (P < 0.0001). Based on multivariate logistic regression
analysis, a history of a stroke was the strongest predictor of new
stroke for both women and men. Low cardiac output syndrome,
atherosclerosis of the ascending aorta, and diabetes mellitus
were significantly associated with stroke for women but not for
men. Analysis on the data from all patients using a gender-
interaction term found that the risk for stroke associated with
patient age, atherosclerosis of the aorta, diabetes, and duration
of cardiopulmonary bypass was not affected by gender. The
prior stroke– gender interaction, however, was significant (P
0.017), suggesting that a prior cerebrovascular event was a
more important predictor of stroke for men than women.
Conclusions: These data show that prior stroke before sur-
gery is strongly and independently associated with susceptibil-
ity for stroke after cardiac surgery, particularly for men. Other
risk factors for perioperative stroke, though, do not appear to
be influenced by patient gender.
WHILE mortality from cardiovascular disease is declining
for men, the rates of death for women have been increas-
ing during the past decade and have even surpassed the
rates for men since the mid-1980s.
1
A rising prevalence
of coronary artery disease coupled with higher mortality
after myocardial infarction and after nonsurgical and
surgical myocardial revascularization procedures for
women compared with men may in part explain these
mortality trends.
1–14
Together, these observations sug-
gest that there are basic biologic differences in the
pathophysiologic responses to coronary artery disease
and its treatments between women and men. Under-
standing the mechanisms for gender differences in out-
comes from cardiovascular diseases and related interven-
tions is thus justifiably receiving increasing attention.
Stroke after cardiac surgery is an important cause of
mortality, health resource utilization, and impaired qual-
ity of life.
4,5,15–26
In an analysis of single-institution and
multiinstitutional data, our group has shown that female
gender is associated with risk for stroke after cardiac
surgery independent of other stroke risk factors and that
this higher risk explains a large portion of the excess
operative mortality for women.
4,5
Variables identifying
risk for perioperative neurologic injury, therefore, could
be influenced by patient gender. Prior investigations that
have developed predictive risk models for this compli-
cation, nonetheless, have mostly combined data from
both men and women.
17,19,22–24
If factors that affect
stroke risk vary between genders, the latter approach
may fail to properly identify those factors that predis-
pose women and men separately for perioperative
stroke. The latter would have adverse effects on risk
stratifying patients for surgery as well as on the devel-
opment of stroke preventative strategies or treatments.
Accordingly, the purpose of this study was to evaluate
whether patient gender impacts adjusted risks for stroke
after cardiac surgery.
Materials and Methods
The population consisted of 2,972 patients (out of
3,321 consecutive individuals) aged 50 yr or younger
who were undergoing cardiac surgery at a single institu-
tion that was part of a previously reported series.
4
There
were 1,900 men and 1,072 women. This study was
approved by the Human Studies Committee at Washing-
ton University (St. Louis, Missouri). Details of the data
collection have been reported.
4,5,21,25
Demographics
and preoperative patient data were prospectively re-
corded in an institutional database by trained research
nurses. These data included history of a prior stroke that
was verified by review of medical records, and the re-
sults of computed tomography and/or magnetic reso-
nance imaging when available, or by contacting the
patient’s primary care physician. Left ventricular func-
tion was assessed with angiography at the time of coro-
nary artery angiography using criteria of the Coronary
* Associate Professor, † Assistant Professor, Department of Anesthesiology,
‡ Associate Professor, Division of Biostatistics, § Associate Professor, Cardiovas-
cular Division, Department of Internal Medicine.
Received from the Department of Anesthesiology, the Division of Biostatistics,
and the Cardiovascular Division, Department of Internal Medicine, Washington
University School of Medicine, St. Louis, Missouri. Submitted for publication
February 18, 2002. Accepted for publication July 15, 2002. Supported in part by
grant No. RO1 HL64600 from the National Heart, Lung, and Blood Institute, the
National Institutes of Health, Bethesda, Maryland (to Dr. Hogue).
Address reprint requests to Dr. Hogue: Department of Anesthesiology, Wash-
ington University School of Medicine, 660 South Euclid Avenue Box 8054, St.
Louis, Missouri 63110. Address electronic mail to: hoguec@notes.wustl.edu.
Individual article reprints may be purchased through the Journal Web site,
www.anesthesiology.org.
Anesthesiology, V 98, No 4, Apr 2003 823
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