Discussion
The findings of the study show that Septuagenarians have better surgical
outcomes compared to Octogenarians undergoing CABG, with the latter
group exhibiting worse results in females. Specifically, the
Septuagenarians overall had less complications and mortality than the
Octogenarians. The impact of these results allows cardiothoracic
surgeons to advise medical professionals that patients above 80 years
old should have percutaneous revascularization if the option is
available. The design of the study is unique in that most of the studies
in the literature compare older patients to younger patients with a
wider age range.
In patients undergoing CABG, age and gender are independent risk factors
for morbidity and mortality [13, 14]. However, some studies have
argued that preoperative risk factors and treatment methods are
responsible for the perceived effects of age and sex [15] and others
have reported no significant differences attributable to these factors
[16]. In 2012, Nicolini et al. [17] investigated early and late
outcomes in octogenarians undergoing CABG, advocating that advanced age
should not be a deterrent for CABG in carefully selected patients. They
showed that candidate selection based on evaluation of systemic
comorbidities offered the greatest benefit to successful
revascularization. These findings, although different from our study
results, highlight the fact that careful patient selection, regardless
of age, is critical in surgical outcomes.
Further support of our results comes from Nicolini et al. in a follow up
study to his previous work, in which they determined that patients’ ≥80
years old had the highest of all cause and cardiac related death, as
well as, increased rates of re-hospitalization and repeat
revascularization with PCI [18]. Additionally, Piatek et al.
[19] reported a mortality of 7% in octogenarians compared to 3.4%
for all CABG procedures at their institution. Prolonged mechanical
ventilation, thoracotomy, and longer duration of procedure are described
as risk factors for in-hospital mortality in this group, while higher
LVEF (Left Ventricular Ejection Fraction) and LIMA (Left Internal
Mammary Artery) graft implantation were found to decrease in-hospital
mortality. In contrast, Smith et al. [16], reported that CABG in
Octogenarians is as safe as and no costlier than in Septuagenarians.
However, the relatively small number of Octogenarians (n=71) compared to
young (n=579) and old (n=384) Septuagenarians limit the impact of this
study.
An additional aspect evaluated in our analysis is the gender difference
on outcomes in Octogenarians. There is a perception amongst
cardiothoracic surgeons that elderly women have worse surgical outcomes
than men. The premise is based on the thought that older women are
frailer and as a result not as robust to handle open-heart surgery. In
fact, one of the significant benefits of transcatheter aortic valve
replacement (TAVR) is that a median sternotomy is avoided in “elderly”
and “frail” patients. This luxury is not afforded for cardiothoracic
surgeons who generally must perform a median sternotomy to perform CABG.
As a result, being able to decipher which patients may benefit from CABG
over PCI is critical to generating optimal outcomes. The findings of the
study are supported in the literature [9-11]. Furthermore, most
reports in CABG suggest that female gender is an incremental risk factor
for adverse outcome [12].
In an assessment of CABG in 1303 patients, Miskowiec et al. [14]
reported females undergoing CABG were significantly older (67.3 vs. 62.8
years, p <0.001) than males and were subject to higher 30-day
mortality (7.6% vs. 2.8% p <0.001). Based on their analysis,
they determined that female sex was an independent risk factor for death
after isolated CABG, which supports our findings of higher mortality (OR
1.25 95% CI 1.07-1.46) in females compared to males. Our analysis also
revealed significantly higher infections in females (OR 1.7206 95% CI
1.58-1.87). The higher infections in females were also reported by
Al-Alao et al. [15], however, they also reported that early outcomes
in females were similar to their matched males. Koch et al. [20]
additionally reported that in matched patients, female sex was not
associated with increased mortality after CABG.
Furthermore, Bernt et al. [21] reported no significant difference in
complications and major morbidity between males and females, suggesting
that gender disparities in outcomes may be improved through individual
revascularization strategies. Bukkapatnam et al. [22] evaluated the
operative mortality in a large cohort undergoing isolated CABG and
determined that operative mortality was significantly higher in females
than in males (4.60% vs. 2.53%, p<0.0001). They also found
that females were less likely to receive an internal mammary artery
(IMA) graft. Leavitt et al. [23] and Piatek et al. [19]
reported left internal mammary artery graft implantation decreased
mortality, supporting Bukkapatnam et al.’s [22] interpretation that
decreased IMA use contributed to the higher mortality in females. As
there are numerous hormonal and sex specific variables that may affect
coronary vessel disease and CABG outcomes, this is an area of study that
requires further in-depth analysis.