Clinical InvestigationImaging and Diagnostic TestingAortic 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
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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