Supervisión con ecocardiografía 3D en tiempo real intraoperatoria de la implantación de prótesis valvular aórtica por vía transapical

Prosthesis sizing for transcatheter aortic valve implantation--comparison of three dimensional transesophageal echocardiography with multislice computed tomography

BACKGROUND

The complex anatomy of the aortic annulus warrants the use of three dimensional (3D) modalities for prosthesis sizing in transcatheter aortic valve implantation (TAVI). Multislice computed tomography (MSCT) has been used for this purpose, but its use may be restricted because of contrast administration. 3D transesophageal echocardiography (3D-TEE) lacks this limitation and data on comparison with MSCT is scarce. We compared 3D-TEE with MSCT for prosthesis sizing in TAVI.

METHODS

Aortic annulus diameters in the sagittal and coronal plane and annulus areas in 3D-TEE and MSCT were compared in 57 patients undergoing TAVI. Final prosthesis size was left at the operator's discretion and the agreement with 3D-TEE and MSCT was calculated.

RESULTS

Sagittal diameters on 3D-TEE and MSCT correlated well (r=.754, p<.0001) and means were comparable (22.3±2.1 vs. 22.5±2.3 mm; p=0.2; mean difference: -0.3 mm [-3.3-2.8]). On 3D-TEE, coronal diameter and annulus area were significantly smaller (p<.0001 for both) with moderate correlation (r=0.454 and r=0.592). Interobserver variability was comparable for both modalities. TAVI was successful in all patients with no severe post-procedural insufficiency. Final prosthesis size was best predicted by sagittal annulus diameters in 84% and 79% by 3D-TEE and MSCT, respectively. Agreement between both modalities was 77%.

CONCLUSIONS

Annulus diameters and areas for pre-procedural TAVI assessment by 3D-TEE are significantly smaller than MSCT with exception of sagittal diameters. Using sagittal diameters, both modalities predicted well final prosthesis size and excellent procedural results were obtained. 3D-TEE can thus be a useful alternative in patients with contraindications to MSCT.

Severe aortic valve stenosis with low-gradient and preserved ejection fraction: a misclassification issue?

INTRODUCTION AND OBJECTIVES

Low-gradient severe aortic stenosis with preserved ejection fraction is a controversial entity. Misclassification of valvulopathy severity could explain the inconsistencies reported in the prognosis of these patients. Planimetry of the aortic area using three-dimensional transesophageal echocardiography could clear up these doubts. The objectives were to assess the agreement between measurements of the valvular aortic area by continuity equation in transthoracic echocardiography and that obtained through planimetry with three-dimensional transesophageal echocardiography in low-gradient severe aortic stenosis patients.

METHODS

Cross-sectional descriptive study of consecutive patients referred due to severe aortic stenosis. Patients underwent transthoracic echocardiography and three-dimensional transesophageal echocardiography. Paradoxical low-gradient severe aortic stenosis was defined by the presence in the transthoracic echocardiography of aortic valve area<1 cm(2), mean ventricular gradient<40 mmHg, and ejection fraction ≥ 50%. Concordance between the two techniques was evaluated.

RESULTS

Of 212 consecutive severe aortic stenosis patients evaluated, 63 cases (29.7%) fulfilled the paradoxical low-gradient inclusion criteria. We obtained three-dimensional aortic valve planimetry in 61 (96.8%) of those patients. In 52 patients (85.2%), aortic valve area by transesophageal echocardiography was <1 cm(2). The intraclass correlation coefficient between the two methods was 0.505 (95% confidence interval, 0.290-0.671; P<.001).

CONCLUSIONS

Paradoxical low-gradient severe aortic stenosis is an actual entity, confirmed in 85% of cases evaluated by three-dimensional transesophageal echocardiography.

Multimodality imaging throughout transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is a novel, less-invasive technique used to treat selected patients with severe aortic valve stenosis with a high surgical risk. Noninvasive imaging before, during and after the procedure is of the utmost importance in this minimally invasive procedure. Screening of the patient and sizing of the aortic root by echocardiography and multislice computed tomography is of great importance to ensure success of the TAVI procedure. Echocardiography and fluoroscopy are essential during the procedure. During follow-up of the patients, echocardiography is important to evaluate the prosthesis function, durability and integrity. Additionally, multislice computed tomography and MRI might be helpful in the follow-up of selected cases. This article outlines the evolving role of multimodality imaging throughout TAVI in patients with severe aortic valve stenosis. It describes, in a stepwise approach, how multimodality imaging by echocardiography, angiography, multislice computed tomography and MRI enhances the TAVI procedure.