Analysis of Pre and Perioperative Factors Associated with
Mortality
To assess the effect of type of aortic repair on overall mortality, a
multivariable Cox proportional hazard model of pre and intraoperative
factors was built (Figure 2 and Appendix Table 3) . Adjustments
were made for age, gender, presence of antegrade cerebral perfusion,
prior myocardial infarction, preoperative renal failure, peripheral
artery disease, chronic lung disease, hyperlipidemia, hypertension, and
concomitant coronary artery bypass grafting, the presence of a total
arch repair was associated with a 2.53 time increase in mortality (HR
2.53, 95% CI 1.38 – 4.62, p = 0.003) as compared to a hemiarch repair.
The other strong predictor of mortality in this analysis was increasing
age, with a 1.76 time increase per 10 years of age (HR 1.76, 95% CI
1.37 – 2.28, p<0.001). Testing for an interaction between age
and type of aortic repair was not statistically significant. While the
other factors were not significant, they were left in the final model
due to their level of significance on univariable analysis and clinical
plausibility as a confounder. However, removal of each non-significant
covariate did not alter the overall assessment of the relationship of
either type of aortic arch repair or age in relationship to mortality.
Predicted survival curves demonstrating the strong relationship with
mortality between type of aortic repair (total arch or hemiarch) and age
are shown in Figure 3 .