Aortic Root Dimensions Among Patients with Severe Aortic Stenosis Undergoing Transcatheter Aortic Valve Replacement

OBJECTIVES:

The aim of this study was to characterize aortic root dimensions of patients with aortic valve stenosis undergoing transcatheter aortic valve replacement (TAVR) and to evaluate sex differences.

BACKGROUND:

The advent of TAVR makes a precise delineation of the aortic root anatomy mandatory and requires a profound anatomic understanding.

METHODS:

Patients planned to undergo TAVR underwent screening imaging with use of a 64-slice or dual-source electrocardiogram-gated contrast-enhanced computed tomography. Anatomic dimensions were assessed at the level of the left ventricular outflow tract (LVOT), annulus, sinus of Valsalva, and ascending aorta.

RESULTS:

The study population comprised 80 men and 97 women (age: 82 ± 6 years) with symptomatic severe aortic valve stenosis. Multislice computed tomography aortic root assessment revealed larger annular and LVOT dimensions in men than women (area annulus: 483.1 ± 75.6 mm(2) vs. 386.9 ± 58.5 mm(2), p = 0.0002; area LVOT: 478.2 ± 131.0 mm(2) vs. 374.0 ± 94.2 mm(2), p = 0.0024), whereas dimensions of the ascending aorta were comparable. Both LVOT and annulus were predominantly oval without sex differences, with a higher mean ellipticity index for the LVOT compared with the annulus (1.49 ± 0.2 vs. 1.29 ± 0.1); the ascending aorta was primarily circular (1.07 ± 0.1). Although similar in mean surface area, an area mismatch of annulus and LVOT of more than 10%, 20%, and 40% was detected in 42, 9, and 2 patients, respectively. The mean distance from annulus to the left coronary ostium was smaller than the mean distance of the right coronary ostium (14.4 ± 3.6 mm vs. 16.7 ± 3.6 mm), and distances were lower among women than men.

CONCLUSIONS:

The aortic root has specific anatomic characteristics, which affect device design, selection, and clinical outcome in patients undergoing TAVR. Female sex is associated with smaller annular and LVOT but not aortic dimensions. The degree of ellipticity as well as a significant mismatch between annular and LVOT dimensions in selected patients deserve careful evaluation.