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 (9, 10). However, some studies have argued that preoperative risk factors and treatment methods are responsible for the perceived effects of age and sex (11) and others have reported no significant differences attributable to these factors (12). In 2012, Nicolini et al. (13) 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 (14). Additionally, Piatek et al. (15) 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. (12), 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 do. 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 (16-18). Furthermore, most reports in CABG suggest that female gender is an incremental risk factor for adverse outcome (19).
In an assessment of CABG in 1303 patients, Miskowiec et al. (10) 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. (11), 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 maybe 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. (15) 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.