4D MDCT in the assessment of the tricuspid valve and its spatial relationship with the right coronary artery: A customized tool based on computed tomography for the planning of percutaneous procedures

Abstract

Multidetector computed tomography (MDCT) is currently the imaging technique of choice for the assessment of tricuspid valve (TV) annulus geometry and relationship with the right coronary artery (RCA). However, standardized protocols with a full 3D analysis are still lacking to plan percutaneous procedures for functional tricuspid regurgitation (FTR). A novel customized 4-dimensional tool based on MDCT data was developed and provided accurate information on TV annulus morphology (3D-perimeter, 2D-Area, maximum and minimum diameters, eccentricity index), function and distance to the RCA, crucial for patient selection of percutaneous TV procedures.

Right Heart Morphology of Candidate Patients for Transcatheter Tricuspid Valve Interventions

“…The annulus dimensions and clinical characteristics of the ‡ 3 + TR group were consistent with ‡ 3 + TR and prior quantitative studies. 1,7,8,18,21 A wide range of annular dimensions were observed in this study with overlap between the studied groups (Table 3, Figure 4). In considering these data along with the echocardiography-based measures of regurgitation and leaflet geometry, this overlap represents the spectrum of annulus geometries for which greater than moderate TR can occur, and similarly the range for which trace to no TR can exist.…”

“…Quantifying annulus-to-RCA distance is performed during patient screening for therapies in which the annular shelf is penetrated by the implant or its attachments. 6,8,13,21,27 No practical differences in annulus-to-RCA distances were observed between the studied patient groups. This finding is consistent with prior studies showing no difference in annulus-to-RCA distance between FTR patients with TR ‡ 3 + and those with TR < 3 +, and the annulus-to-RCA distance being independent of sex, age, body weight, and etiology.…”

“…The study sample size is small relative to clinical trials but exceeds or is comparable in size to studies evaluating right heart anatomical features in patients with moderate or greater FTR (sample size range: N = 8-40). 8,15,16,20,21,27 The sample size of this study is however lesser in size than a control arm of one study, in which the annulus-to-RCA distances and IVC dimensions were quantified in subjects with < 3 + TR (N = 210). 27 In a subset of patients, the annulus-to-RCA distance was unable to be determined in the posterolateral and posterior segments due to the RCA diameter decreasing to or below the spatial resolution of the CCTA images, insufficient intraluminal contrast, or both.…”

“…Recent research has quantified phasic right heart chamber dimensions and volumes, tricuspid annulus dimensions, annulus-to-right coronary artery (RCA) distances, and inferior vena cava (IVC) dimensions in FTR patients. 7,8,11,15,16,20,21,27 These data however have been unable to capture other critical features for transcatheter therapies, including the position of the vena cava with respect to the TV, vena cava delivery axis angles and heights, the topography of the tissue encircling the TV annulus, annulus excursion, and their correlation to other right heart features. 3 These knowledge and data gaps are attributed to several factors.…”

Multimodality cardiac imaging and new display options to broaden our understanding of the tricuspid valve

“…Dedicated tools are mainly used for TA sizing. However, using end-systolic MDCT data (30-40% of cardiac cycle) they provide also measurement of the extent of leaflet tethering or the 3D tenting volume, as well as landmark structure localization [26][27][28] (Fig. 3).…”