Right ventricular volumes and ejection fraction are challenging to assess by echocardiography, but are well established as functional and prognostic parameters. Three-dimensional (3D) echocardiography has become widespread and relatively easy to use, making calculation of these parameters feasible in the large majority of patients. We review past attempts to estimate right ventricular volumes, current strengths and weaknesses of 3D echocardiography for this task, and compare with corresponding data from magnetic resonance imaging.
Ellen Ostenfeld and Frank A Flachskampf
Frank A Flachskampf and Petros Nihoyannopoulos
Normal values provide the background for interpretation of quantitative imaging data and thus are essential information for daily routine. Nevertheless, the ways how normal values are obtained, presented and interpreted, often do not receive the attention they deserve. We review the concepts of normalcy, the implications of typical normal ranges including the types of distribution of normal data, the possibilities to index for confounding biological factors like body surface area and the limitations of the very concept of normal values, demonstrating that there are no easy statistical solutions for difficult clinical problems.
Inga Jona Ingimarsdóttir, Laila Hellgren and Frank A Flachskampf
Objectives: The aortic annulus diameter measured by transthoracic echocardiography yields lower values than by computed tomography, and echo-based selection of transcatheter aortic valve prosthesis size has been implied to result in more frequent paravalvular leakage. We investigated the relation of preoperative annulus diameter by echo with the ring size of the aortic prosthesis chosen by direct assessment during open heart aortic valve replacement.
Methods: Preoperative annulus diameter by echo (from parasternal long axis cross-sections of the left ventricular outflow tract and aortic valve) and implanted prosthetic diameter (tissue annulus diameter, determined intraoperatively using a sizing instrument) were compared retrospectively in 285 consecutive patients undergoing open heart aortic valve replacement.
Results: A total of 285 prostheses (240 biologic and 45 mechanical) were implanted, with prosthetic diameter ranging between 19 and 27 mm. There was a significant linear correlation (p<0.0001) with r = 0.51, between preoperative annulus diameter by echo (mean 21.8 ± 2.8 mm) and prosthetic diameter (22.9 ± 1.7 mm). Preoperative annulus diameter of patients receiving prostheses No. 21, 23 and 25 mm aortic prostheses (the most frequent prosthesis sizes) were significantly different (p<0.001) from each other. On average, preoperative annulus diameter by echo underestimated prosthetic diameter by a bias of 1.07 mm.
Conclusion: Our data confirms that preoperative echo assessment of the aortic valve may slightly underestimate the optimal surgical prosthesis diameter for the aortic valve annulus.