Table 1:
Results of multilevel mixed-effects linear model to assess the influence of anatomical region on the material constants of the aortic wall in ATAA
| Coef | Standard error | 95% CI | P-Value | |
|---|---|---|---|---|
| (a) | ||||
| Outer curve versus other regions | 0.014 | 0.005 | 0.0036–0.0249 | 0.009 |
| Patient | 0.032 | 0.019 | 0.010 to 0.105 | |
| Orientation | 5.13 × 10−24 | – | – | |
| Var (estimate ɑ-Delfino parameter) | 0.002 | 0.0019 | 0.0017 to 0.0025 | |
| Likelihood ratio test versus linear model | 0.027 | |||
| (b) | ||||
| Outer curve versus other regions | −0.995 | 0.446 | −1.868 to −0.121 | 0.009 |
| Patient | 0.512 | 0.499 | 0.076 to 3.459 | |
| Orientation | 3.17 × 10−18 | – | – | |
| Var (estimate µ1-Ogden parameter) | 5.937 | 0.891 | 4.424–7.967 | |
| Likelihood ratio test versus linear model | 0.428 | |||
The fixed effects part of the model tested the influence of anatomical region (outer curve versus other regions) on the (a) ɑ-Delfino parameter and (b) µ1-Ogden parameter. The random effect part of the models tested the influence of the patient, and sample orientation (longitudinal versus circumferential). From these results, the influence of region on the material property is significant, with the added influence of the patient from which the sample was sourced. The effect of sample orientation on the value of the material constant in these models was negligible.
CI: confidence interval.