Elsevier

American Heart Journal

Volume 164, Issue 4, October 2012, Pages 576-584
American Heart Journal

Clinical Investigation
Imaging and Diagnostic Testing
Aortic annulus area assessment by multidetector computed tomography for predicting paravalvular regurgitation in patients undergoing balloon-expandable transcatheter aortic valve implantation: A comparison with transthoracic and transesophageal echocardiography

https://doi.org/10.1016/j.ahj.2012.06.024Get rights and content

Background

Transcatheter aortic valve implantation (TAVI) is a valid alternative to surgery in high-risk patients with severe aortic stenosis. Aortic annulus (AoA) sizing is crucial for TAVI success. The aim of the study was to compare AoA dimensions measured by multidetector computed tomography (MDCT) vs those obtained with transthoracic (TTE) and transesophageal echocardiography (TEE) for predicting paravalvular aortic regurgitation (PVR) after TAVI.

Methods

Aortic annulus maximum diameter, minimum diameter, and area were assessed using MDCT and compared with TTE and TEE diameter and area for predicting PVR after TAVI in 151 patients (45 men, age 81.2 ± 6.4 years).

Results

Aortic annulus maximum, minimum diameter, and area detected by MDCT were 25.04 ± 2.39 mm, 21.27 ± 2.10 mm, and 420.87 ± 76.10 mm2, respectively. Aortic annulus diameter and area measured by TTE and TEE were 21.14 ± 1.94 mm and 353.82 ± 64.57 mm2 and 22.04 ± 1.94 mm and 384.33 ± 67.30 mm2, respectively. A good correlation was found between AoA diameters and area evaluated by MDCT vs TTE and TEE (0.61, 0.65, and 0.69 and 0.61, 0.65, and 0.70, respectively), with a mean difference of 3.90 ± 1.98 mm, 0.13 ± 1.67 mm, and 67.05 ± 55.87 mm2 and 3.0 ± 2.0 mm, 0.77 ± 1.70 mm, and 36.54 ± 56.43 mm2, respectively. Grade ≥2 PVR occurred in 46 patients and was related to male gender, higher body mass index, preprocedural aortic regurgitation, and lower mismatch between the nominal area of the implanted prosthesis and AoA area detected by MDCT.

Conclusions

Mismatch between prosthesis area and AoA area detected by MDCT is a better predictor of PVR as compared with echocardiography mismatch. Specific MDCT-based sizing recommendations should be developed.

Section snippets

Methods

Between April 2008 and April 2011, 260 consecutive patients with severe AS were referred to our institute for TAVI. In 11 patients (7%), TAVI was not performed because of contraindications, whereas 3 (2%) patients were treated with surgical valve replacement due to complications occurring during the percutaneous procedure. Exclusion criteria for MDCT before TAVI were severe impaired renal function (creatinine clearance <30 mL/min), inability to sustain a 10-second breath-hold, atrial

Results

Clinical characteristics, echocardiography, and MDCT findings of the study patients at baseline and after TAVI are summarized in Table I. All patients had severe AS (indexed aortic valve area 0.38 ± 0.09 cm2/m2). The preprocedure aortic regurgitation was scored as grade 0, 1, 2, 3, and 4 in 114 (75.5%), 23 (25.2%), 8 (5.3%), 5 (3.3%), and 0 (0%) patients, respectively. AoA diameter and area measured by TTE and TEE were 21.14 ± 1.94 and 22.04 ± 1.94 mm and 353.82 ± 64.57 and 384.33 ± 67.30 mm2,

Discussion

The main findings of our study are as follows: (a) the shape of the AoA is elliptical and not circular; (b) there is a minimal difference between AoA minimum diameter measured by MDCT and both AoA-Ds evaluated by TTE and TEE, whereas a significant difference was found vs AoA maximum diameter measured by MDCT in comparison with TTE and TEE; (c) both TTE and TEE underestimate annulus size as compared with MDCT likely because of the assumption that AoA has a circular shape; (d) a mismatch of 61.5

Limitations of the study

Several limitations are present in this study. First, because PVR was evaluated by echocardiography at the end of the procedure, the shortcomings of assessing eccentric jets by echocardiography have to be kept in mind.25 Second, the incongruence between prosthesis and AoA-A was considered the underlying cause of aortic regurgitation. However, several other mechanisms may be involved such as valvular damage during implantation, too low implantation of the valve, and valve malapposition due to

Conclusions

This study shows that the lack of congruence between prosthesis and annulus size is associated with PVR. Multidetector computed tomography is a better tool for detecting the mismatch between prosthesis area and AoA-A and for predicting PVR as compared with TTE and TEE. An MDCT-based approach may be a reliable method to select the appropriate prosthesis size for TAVI. In this regard, specific MDCT-based sizing recommendations should be developed.

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