Aortic valve leaflet and root dimensions in normal tricuspid aortic valves: A computed tomography study

Abstract

Background and Aim of the Study: The aim of this study was to use coronary computed tomography in patients with normal tricuspid aortic valves to perform detailed aortic root and aortic valve geometric analysis with a focus on the asymmetry of the three leaflets.Methods: Retrospective analysis of anonymized coronary computed tomography angiograms was performed using dedicated software, where manual aortic root segmentation and marking of several points of interest were followed by automated measurements of aortic root and leaflets. Asymmetry of the three leaflets in individual patients was assessed by calculating absolute and relative differences between the largest and the smallest of the three leaflets.Results: We analyzed 70 aortic valves, the mean patient age was 53 ± 11 years, and 50% (n = 35) of patients were female. All aortic valves were tricuspid, without calcifications and aortic roots were of normal dimensions. Some degree of asymmetry was present in all analyzed valves. Absolute and relative differences for free margin length were 3.2 ± 1.4 mm and 9.3 ± 3.8%, respectively. The largest relative difference was noted in the coaptation area (36.5 ± 16.5%) and the smallest in leaflet effective height (6.1 ± 4.8%). Using predefined cutoff criteria for absolute differences in leaflet dimensions, 86% of the valves were classified as asymmetric.Conclusions: Most normal tricuspid aortic valves show some degree of asymmetry.Equal free margin length of the three leaflets is not needed for normal tricuspid aortic valve function. Leaflet effective height showed the least amount of asymmetry confirming its importance in keeping the aortic valve competent.

Functional and pathomorphological anatomy of the aortic valve and root for aortic valve sparing surgery in tricuspid and bicuspid aortic valves

“…The coaptation area composed of the two lunules, has an average surface of 1.2 cm 2 (0.6 cm 2 per lunule) in the normal TAV, representing approximately 40% of the leaflet surface ( Figure 6 ) ( 18 ). Other studies, using three-dimensional imaging, report a coaptation surface between adjacent leaflets (one lunule) of 0.5 cm 2 by echocardiography and 0.8 cm 2 by CT ( 33 , 36 ). The coaptation surface remains difficult to assess especially intraoperatively; therefore, two-dimensional measurements (e.g., echocardiography) of the coaptation area are preferred to assess the valve, after valve-sparing surgeries or AV-repair procedures.…”

“…There are small differences between free edge length of the three leaflets in a normal TAV; the right coronary leaflet is slightly longer followed by the non- and left coronary leaflets. The free edge can also be measured by CT using three-dimensional reconstruction ( 32 , 33 ). In these studies, the average free edge length was 33 or 34 mm, very similar results compared to ex - vivo analysis where leaflets were measured on fresh specimen and left attached to the aortic root ( 1 , 18 ).…”

“…eH can be measured intraoperatively with a dedicated caliper ( 37 ) and it can be measured by transesophageal echocardiography. Coaptation length is the height of the zone of leaflet apposition (height of the lunule); it is best measured by three-dimensional echocardiography or CT. Coaptation height is on average 3 mm at the level of the Nodulus of Arantius and it increases to 6 mm on average at the middle portion of the lunule ( 18 , 33 ). Coaptation length, as well as eH, can be used as a predictor for repair durability ( 13 , 38 ).…”

“…The commissure height or the root height is measured from the basal ring to the STJ. In normal TAVs, the average commissure height is 21 mm by direct measurement of fresh aortic homograft specimen, and 17–18 mm by CT imaging ( 18 , 32 , 33 ). The commissural height between the right/non-coronary leaflets is slightly larger compared to the height of the commissure between the left/right and the non/left.…”

Aortic Valve Repair and Early-Career Surgeons—Nothing Is Impossible

“…The procedure is undoubtedly complex and requires a thorough theoretical as well as practical knowledge from the whole heart team, especially the primary surgeon. Early-career surgeons, who wish to start their own AV repair program, should be familiar with the anatomy and (patho)physiology of the aortic root with the knowledge gained from both cadaveric specimens [2], echocardiography [3], and novel imaging modalities, such as computer tomography reconstructions [4,5]. Perhaps even more important than with mitral valve repair is a sufficient understanding of the mechanisms leading to aortic root pathology; this is imperative so that one can identify suitable candidates among their patients to achieve durable AV repair.…”