Author + information
- Ignacio J. Amat-Santos, MD∗ (, )
- Ana Revilla, MD,
- Javier López, MD, PhD,
- Carlos Cortés, MD,
- Hipólito Gutiérrez, MD,
- Ana Serrador, MD, PhD,
- Federico Gimeno, MD, PhD,
- Ana Puerto, MSc,
- Itziar Gómez, MSc and
- José A. San Román, MD, PhD
- ↵∗Institute of Heart Sciences, Hospital Clínico Universitario de Valladolid, C/ Ramón y Cajal 3, 47005 Valladolid, Spain
Current guidelines on valvular heart disease recommend double valve replacement when significant aortic stenosis and mitral regurgitation (MR) occur simultaneously (1,2). Given the higher risk of combined mitro-aortic surgery, transcatheter aortic valve replacement (TAVR) has emerged as a good alternative, with a constant improvement (up to 60%) in MR degree after TAVR (3), especially if the MR was of functional etiology. However, the definition of functional MR is challenging in patients with TAVR. The value of multidetector computed tomography (MDCT) in the assessment of mitral valves in this scenario is unknown (4); therefore, our aims were to: 1) confirm the feasibility of mitral valve characterization with MDCT in the context of TAVR; and 2) determine MDCT predictors of MR improvement.
One hundred consecutive patients diagnosed with severe aortic stenosis were treated by transfemoral TAVR with the CoreValve system (Medtronic Inc., Minneapolis, Minnesota) in our institution. Six patients with previous mitral mechanical prosthesis were excluded from the analysis. Patients were classified, according to their echocardiographic baseline degree of MR, in “low-degree MR” for grades 0 and 1 (effective regurgitant orifice [ERO] <2 cm2; i.e., none or mild) or “high-degree MR” for grades 2, 3, and 4 (ERO ≥2 cm2; i.e., moderate for 2 and 3 and severe for 4) (1,2). We considered an improvement in MR to be significant when degree of MR changed from high to low.
All patients underwent complete serial transthoracic echocardiography. Offline analysis was performed by 3 experienced echocardiographers (A.R., J.R.A., and J.A.S.R.) blinded to further data. Transesophageal echocardiography was only performed when clinically indicated (in 10 patients with ERO ≥0.3 cm2 and unclear functional/organic etiology).
MDCT examinations were performed with a 64-row MDCT scanner (LightSpeed VCR, GE Healthcare, Little Chalfont, United Kingdom) during inspiratory breath-hold using contrast (iohexol 350 mg/ml) in a nongated fashion. MDCT was used to measure mitral annulus diameter. Location and degree of calcification of the mitral annulus and leaflets were semi-quantitatively graded as described in Figure 1. Analysis of MDCT images was carried out by an expert in cardiac imaging (A.R.).
Mitral annulus size measured was related to MR improvement with a high echocardiographic/MDCT correlation (0.996; 95% confidence interval [CI]: 0.993 to 0.998). The cutoff value that best predicted MR improvement was 35.95 mm. The echocardiographic degree of calcification affecting the mitral valve structures did not show significant differences. In contrast, the presence of any degree of leaflet calcification (≥1) by MDCT was an independent predictor of lack of MR improvement (76.5% vs. 23.1%, OR: 6.8 [95% CI: 1.3 to 37.0], p = 0.026), as well as mitral annulus diameter (34.7 ± 3.5 mm vs. 39.7 ± 3.8 mm, OR: 13.5 [95% CI: 2.5 to 76.9], p = 0.003). In addition, the detection of calcium at the mitro-aortic junction by MDCT, related to higher likeliness of left bundle branch block, determined a higher risk of MR persistence. On the contrary, calcification of the mitral annulus was not associated with the evolution of MR.
MDCT is particularly useful in patients undergoing TAVR (1,2) to evaluate the aorto-iliac axis and for providing relevant information on mitral valve to predict long-term MR improvement after TAVR. It is not clear why calcification of some of the mitral apparatus elements is associated with MR improvement but not calcification of other parts. We believe that mitral leaflet stiffness provoked by calcium is an important determinant of MR and its remains. These findings will have to be clarified in future prospective research due to the limited number of patients, which restricted multivariate analysis.
In conclusion, MDCT analysis of the mitral anatomy in patients undergoing TAVR determined the absence of calcification of mitral leaflets and lower annulus diameter as main predictors of MR improvement. The extended use of MDCT in TAVR candidates and the simplicity of these measurements may be helpful in the decision-making process for patients with mitro-aortic disease given the current controversy about their management.
Please note: Dr. Amat-Santos has received financial support from the Instituto de Salud Carlos III, Madrid, Spain, through a contract “Río Hortega.” All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- American College of Cardiology Foundation
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