The Recurring Theme of Gender Difference in Cardiac Surgical
Outcomes
John S. Ikonomidis MD, PhD
Division of Cardiothoracic Surgery, University of North Carolina at
Chapel Hill
Word Count: 1144
References: 13
Address correspondence to:
John S. Ikonomidis MD, PhD
Professor and Chief,
Division of Cardiothoracic Surgery
University of North Carolina at Chapel Hill
3034 Burnett Womack Building
160 Dental Circle,
Chapel Hill, NC
27599
e-mail: john_ikonomidis@med.unc.edu
Tel: (919) 966-3381
In this issue of the Journal of Cardiac Surgery,1Newell and colleagues examined contemporary national outcomes following
surgical resection of benign primary atrial and ventricular tumors. The
2016-2018 Nationwide Readmissions Database was queried for all patients
> 18 years of age with a primary diagnosis of benign
neoplasm of the heart who underwent resection of the atria, ventricles,
or atrial/ventricular septum. A weighted total of 2,557 patients met
inclusion criteria. Mean age was 61 years, 67.9% were female, and
patients had relatively low comorbidity burdens. The authors found that
while there was no difference in 30-day mortality (2.1% vs 1.3%,
p=0.550), 30-day readmission (7.0% vs 9.1%, p=0.222), or 30-day
composite morbidity (56.8% vs 53.8%, p=0.369) between females and
males respectively, on multivariable analysis, female sex was
independently associated with increased risk of 30-day mortality (OR
2.65, p=0.028).
Overall, this was a well study which documents a large contemporary
cohort of benign cardiac tumor resections. However, perhaps the most
interesting feature of this study is the finding of sex as an
independent predictor of 30 day mortality after propensity matching.
Cardiac surgery suffers from a gender gap in terms of its outcomes. It
has been well established that for many procedures such coronary bypass
surgery (CABG), aortic valve replacement, mitral valve surgery, and
aortic surgery.2 For CABG, women referred for surgery
are typically older than men, have a higher comorbidity (hypertension,
renal failure, diabetes, peripheral vascular disease) profile, and more
often present in urgent or emergent status for
surgery.3 Large, risk-adjusted, propensity matched
studies have documented increased mortality in women as compared with
men.4-7 This difference also extends into the
interventional cardiology realm, where mortality and complication rates
have been shown to be higher in women following percutaneous
interventions for ST-elevation myocardial infarction.8For aortic valve replacement, a Nationwide Inpatient Sample study of
166809 patients with aortic stenosis from 2003 to 2014 found that women
experience higher inpatient mortality (5.6% versus 4%,
P<0.001) which persisted after propensity matching (3.3%
versus 2.9%, P<0.001).9 For mitral valve
surgery, a randomized controlled trial of patients with severe ischemic
mitral insufficiency undergoing repair versus replacement found that
women had higher mortality than men (27.1% versus 17.4%,
p<0.03).10 For aortic surgery, female gender
was associated with a higher mortality after both aortic dissection and
aortic arch repair.11,12 Reduction in surgical stress
through application of minimally invasive approaches still resulted in
female sex being a risk factor for higher in-hospital
mortality.13 The findings of the present study add
further support to the above observations, with the potential addition
that, in contrast to the other disease processes described, the majority
of patients presenting for surgical removal of benign cardiac tumors
were likely free of either symptoms or cardiac sequelae due to the
disease, but nevertheless still the gender disparity in mortality
persisted.
While it is obvious that the above disease processes and their related
surgical remedies are quite disparate, the association with increased
mortality seen in females seems to be constant. Why is this? A
considerable amount has been written regarding sex bias in referral
patterns for surgery and even decreased functional reserve and health
profiles of women when they are referred for surgical intervention
compared with men.2 With regard to these referral
patterns, published guidelines directing practitioners regarding
indications for surgery are, in general, based upon studies in which the
majority of patients were male. Interestingly, in the present study,
females made up over two thirds of the patient
population.1 While this suggests that females carry a
disproportionately more benign cardiac tumors amenable to surgery, the
post-surgical mortality disparity remained.
The exact reasons for the above disparity remain unelucidated and
further work is required to eliminate the gender gap in cardiac surgical
outcomes. There is considerable focus on the removal of sex bias in
animal and human research, as well as the development of disease
treatment guidelines that consider gender in the algorithms. Hopefully
and these and other sex-balanced approaches will reveal new insights
that will allow us to bring equipoise to gender-stratified cardiac
surgical outcomes.