Three-Dimensional Measurement of Aortic Annulus Dimensions Using Area or Circumference for Transcatheter Aortic Valve Replacement Valve Sizing: Does It Make a Difference?

BACKGROUND

The use of transcatheter aortic valve replacement (TAVR) is increasing worldwide. We present our 6-year experience using three-dimensional (3D) transesophageal echocardiography (TEE) and investigate whether different sizing methods of the aortic annulus lead to different prosthesis size that may impact outcome.

METHODS

We investigated 262 patients who underwent TAVR and had 3D TEE data sets of the aortic annulus. We have used the area-derived diameter (Darea = 2(area/π)) and the circumference-derived diameter (Dcirc = Circumference/π) to size the prosthesis in separate populations in different time periods.

RESULTS

The Dcirc method is correlated with lower incidence of paravalvular aortic regurgitation (PVAR; odds ratio = 0.44, 95% confidence interval, 0.23-0.85; P = .015). Other factors associated with PVAR were the cover index, area-mismatch index, and circumference-mismatch index. Retrospectively, for the purposes of the study, we used the Edwards-Sapien 3 Valve 3D sizing guide in all patients, to predict the hypothetical valve size with each method. In the whole population, the calculated Dcirc was higher in all cases (Dcirc = 23.4 ± 2.3 mm vs Darea = 22.9 ± 2.3 mm; P < .001). The two methods had good agreement in predicting the valve size (kappa = 0.600). In total, 192 (73.3%) patients were assigned for the same prosthesis size, whereas 70 (26.7%) would be eligible for a different size, of which 44 (16.7%) would definitely have had a different valve implanted.

CONCLUSION

Using the aortic annulus area or circumference to calculate the annular diameter provides different values. Comparing the two methods, a different prosthesis size could have been implanted in 26.7% of patients. In our series the use of circumference-derived diameter resulted in lower incidence of PVAR. The findings of this study may be independent of the imaging modality and may therefore also apply to computed tomography-based aortic annulus measurements, but this needs to be further investigated.