Page 21 - Journal of Structural Heart Disease Volume 5, Issue 3

Original Scientific Article
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TTE is the first-line imaging modality for evalu- ation of AS severity. However, heterogeneous he- modynamic presentation, measurement errors, and ellipsoidal LVOT may influence the diagnosis and treatment decision for patients with severe AS when TTE is used. A recent study demonstrated that AVA measured by CCT correlated well with AVA assessed by TTE and catheter examination in 100 patients with severe calcified AS regardless of gender, presence of AF and heart rate [26]. Based on the our results which are in line with previous reports [9-15], aortic valve calcium score and LVOT area appeared to be the main factors significantly associated with difference between AVACCT and AVATTE in patients with severe AS and so they may be used to corroborate AS severity in case of discordant findings or poor acoustic windows at TTE. In addition, several factors such as TTE param- eters, aortic valve and annular calcification, LVOT ec- centricity, and AF need to be considered when com- paring AVAs obtained with CCT and TTE. A combined approach using TTE and CCT might have incremental value over TTE alone for the evaluation of AS severity.
The present study has several limitations. First, we observed instances for which the difference be- tween AVACCT and AVATTE was high. However, we do not know which method is more accurate. There is no established non-invasive reference standard for as- sessment of AVA. Furthermore, there was no invasive reference obtained in this study. Second, the hemo- dynamic burden associated with the presence of AS is represented by the effective AVA and not the anatom- ic AVA. These points considerably limit the interpreta- tion of the current findings. Third, the positioning at
the edge of the aortic valve cusps for AVA planimetry by CCT can also generate some discrepancy. This was pointed out by the relative low intra-class coefficient for inter-observer AVA measurements. Fourth, 31% and 19% of patients had moderate or greater mitral and aortic valve regurgitation. In addition, LVEF was diverse between 10% and 73% in this group. These factors would have a significant impact on flow pro- files in both the LVOT and through the aortic valve that would compromise the accuracy of a continuity equation derived AVA compared to direct measure- ment through CCT. Finally, this was a single-institu- tion retrospective study with a relatively small num- ber of highly selected patients who had severe AS and underwent TAVR. This biases towards an older severe AS population with high surgical risk.
In conclusion, in patients being evaluated for TAVR with severe AS the mean AVACCT was significantly larg- er than AVATTE. Age, Agatston aortic valve score, and LVOT area difference between CCT and TTE might af- fect the difference between AVACCT and AVATTE in pa- tients with severe AS. The clinical implications of this discrepancy are unknown and should be an area for future research.
Conflict of Interest
The authors have no conflict of interest relevant to this publication.
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References
1. Nkomo VT, Gardin JM, Skelton TN, Gottdiener JS, Scott CG, Enriquez-Sara-
no M. Burden of valvular heart diseas-
es: a population-based study. Lancet. 5. 2006;368:1005-1011. DOI: 10.1016/s0140- 6736(06)69208-8
echocardiography in transcatheter aortic valve implantation. Echocardiography. 2014;31:101-110. DOI: 10.1111/echo.12369 Kasel AM, Cassese S, Bleiziffer S, Amaki M, Hahn RT, Kastrati A, Sengupta PP. Standard- ized imaging for aortic annular sizing: im- plications for transcatheter valve selection. JACC Cardiovasc Imaging. 2013;6:249-262. DOI: 10.1016/j.jcmg.2012.12.005
Salgado RA, Leipsic JA, Shivalkar B, Ar- dies L, Van Herck PL, Op de Beeck BJ, et al. Procedural CT evaluation of transcath- eter aortic valve replacement: what the radiologist needs to know. Radiograph- ics. 2014;34:1491-1514. DOI: 10.1148/ rg.346125076
7. Mack MJ, Holmes DR, Webb J, Cribier A, Ko- dali SK, Williams MR, et al. Patient selection for transcatheter aortic valve replacement. J Am Coll Cardiol. 2013;62(17 Suppl):S1-10. DOI: 10.1016/j.jacc.2013.08.707
8. Saikrishnan N, Kumar G, Sawaya FJ, Lerakis S, Yoganathan AP. Accurate assessment of aortic stenosis: a review of diagnostic mo- dalities and hemodynamics. Circulation. 2014;129:244-253. DOI: 10.1161/circulatio- naha.113.002310
9. Clavel MA, Malouf J, Messika-Zeitoun D, Araoz PA, Michelena HI, Enriquez-Sarano M. Aortic valve area calculation in aortic stenosis by CT and Doppler echocardiogra- phy. JACC Cardiovasc Imaging. 2015;8:248-
2. Iung B, Vahanian A. Epidemiology of val- vular heart disease in the adult. Nature Reviews Cardiology. 2011;8:162-172. DOI: 10.1038/nrcardio.2010.202
3. Webb JG, Wood DA. Current status of transcatheter aortic valve replacement. J Am Coll Cardiol. 2012;60:483-492. DOI: 10.1016/j.jacc.2012.01.071
4. Bilen E, Sari C, Durmaz T, Keleş T, Bayram NA, Akçay M, et al. The importance of
6.
Journal of Structural Heart Disease, June 2019
Volume 5, Issue 3:52-61