P1447 Ascending aorta longitudinal strain in bicuspid aortic valve patients: a comparison with healthy volunteers and patients with degenerative aortic aneurysm

Funding Acknowledgements

Spanish Ministry of Economy and Competitiveness RTC-2016-5152-1, ISCIII PI17/00381, La Marató de TV3 (20151330), Eur FP7/People 267128 and CIBERCV

Background

Histological findings of fibrillin-1 deficiency in bicuspid aortic valve (BAV) ascending aorta (AAo), as observed in Marfan (MFS), supported the existence of intrinsic aortic wall abnormalities, but recent studies reported the absence of an intrinsic impairment in stiffness. A recent study in MFS showed that AAo longitudinal strain was reduced in MFS and predicted dilation and aortic events. This parameter has not been studied in BAV.

Purpose

We investigated whether ascending aorta longitudinal strain is intrinsically altered in BAV with respect to tricuspid aortic valve (TAV) individuals.

Methods

80 BAV, 31 healthy volunteers (HV) and 29 TAV with AAo aneurysm, all without moderate valvular disease, were consecutively included. AAo dilation was defined as a z-score > 2. The 1.5T CMR protocol included a set of 2D cine CMR stacks covering the proximal aorta in saggital, coronal and axial views. AAo longitudinal strain was computed by an in-house Matlab code performing a feature tracking of the aortic valve in each of the cine images.

Results

Twenty (25%) of BAV had AAo dilation. AAo longitudinal strain was lower in non-dilated BAV compared to HV, but the difference was not significant in multivariate analysis adjusted for AAo diameter and systolic blood pressure. Similarly, the difference between dilated BAV and dilated TAV found in univariate analysis was not confirmed by multivariate analysis. On the other hand, both dilated BAV and TAV showed decreased AAo longitudinal strain compared to HV, which were confirmed in multivariate analyses.

Conclusions

AAo longitudinal strain, a marker of aortic stiffness with predictive value in MFS, is not altered in BAV patients compared to TAV matched for dilation prevalence. Reduced AAo longitudinal strain was independently associated with dilation in both BAV and TAV.

Table 1 HV vs. NON-DILATED BAV DILATED BAV vs DILATED TAV HV vs. DILATED BAV HV vs. DILATED TAV HV NON-DILATED BAV Univariate /multivariate p-value DILATED TAV DILATED BAV Univariate /multivariate p-value Univariate/ Multivariate p-value Univariate p-value N 31 20 29 60 Age [years 35 ± 8 49 ± 16 <0.001/ NS 66 ± 13 49 ± 14 <0.001 / <0.001 <0.001 / 0.052 <0.001 / NS Sex [% male] 42 35 0.629 24 42 0.097 / NS 0.969 0.149 BSA [m2] 1.83 ± 0.17 1.81 ± 0.14 0.702 1.95 ± 0.24 1.82 ± 0.22 0.015 / <0.001 0.881 0.030 / NS SBP [mmHg] 119 ± 11 132 ± 16 0.002 / 0.029 133 ± 17 138 ± 19 0.304 <0.001 / NS <0.001 / NS DBP [mmHg] 69 ± 11 73 ± 6 0.099 / NS 77 ± 9 79 ± 11 0.455 <0.001 / 0.016 0.004 / 0.023 Ascending aorta diameter [mm] 26 ± 4 33 ± 3 <0.001 / 0.006 46 ± 7 43 ± 6 0.032 / NS <0.001 / 0.001 <0.001 /0.007 AAo long strain [%] 10.5 ± 3.6 8.4 ± 4.1 0.067/ NS 5.9 ± 2.7 7.7 ± 3.6 0.023 / NS 0.001 / 0.002 <0.001 / 0.023 Demographics and uni- and multivariate analyses of AAo longitudinal strain

477Partial fusion of two aortic valve leaflets is related to alterations in ascending aorta flow: 4D flow CMR study

Introduction

Bicuspid aortic valve (BAV) is the most common congenital valve defect. It consists in the fusion of two aortic valve leaflets, and it is associated with a high prevalence of proximal aorta dilation. Dilation is highly prevalent (around 30%) in BAV patient relatives with a tricuspid valve (TAV) identified by echocardiography. However, the presence of partial aortic valve leaflet fusion (also called mini-raphe or forme fruste BAV, see figure 1A) is easily missed by echocardiography. A recent study reported that 44% of patients from a small cohort of BAV patient relatives with aortic dilation followed by CT showed mini-raphe.

Purpose

We aimed to use 4D flow CMR to assess if the presence of mini-raphe is associated with aortic flow alterations, which may be concurs in the etiology of aortic dilation in BAV patient relatives.

Methods

Twenty BAV patients first-degree relatives with partial fusion (<50%) of aortic valve leaflets and proximal aorta dilation were identified by CT or cine CMR and prospectively included. One-hundred twenty-five BAV and 95 patients with TAV from our prospective dataset of 4D flow CMR were included for comparison. Propensity score matching was used throughout the study to correct the comparisons between mini-raphe and BAV and mini-raphe and TAV patients for differences in age, maximum aortic diameter, sex, height, weight, proximal aortic pulse wave velocity and, only for BAV, fusion pattern. The hemodynamic parameters previously related to aortic dilation were computed. They were jet angle, normalized flow displacement and systolic flow reversal ratio (SFRR, identifying through-plane vortexes) were computed and compared in the ascending aorta and in the aortic arch.

Results

The presence of mini-raphe was statistically-significantly associated with increase in jet angle (Figure 1B), flow displacement (Figure 1C) and vortexes (Figure 1D) in most of the ascending aorta and aortic arch when mini-raphe patients were compared with TAV patients. The severity of flow asymmetry found in mini-raphe patients was lower than the one characteristic of BAV patients, but vortexes were even higher in a small region at the distal ascending aorta.

Figure 1

Conclusion

Partial fusion of the aortic valve leaflets is related to increase in proximal aorta flow eccentricity and vorticity. These flow abnormalities are not as marked as those associated with BAV. Data regarding prevalence of mini-raphe as evaluated with CT or cine CMR are needed, especially in familiar of BAV patients.

Acknowledgement/Funding

European FP7/People 267128; Spanish Ministry of Economy and Competitiveness RTC-2016-5152-1 and Instituto de Salud Carlos III PI14/0106