Mohammad Abdelghani1, Ernest Spitzer2,3, Osama I I Soliman2,3, Dietrich Beitzke4, Roberta Laggner4, Rafael Cavalcante3, Hiroki Tateishi3, Carlos M Campos5,6, Luc Verstraeten7, Yohei Sotomi1, Erhan Tenekecioglu3, Yoshinobu Onuma2,3, Jan G Tijssen8, Robbert J de Winter8, Francesco Maisano9, Patrick W Serruys10. 1. Depatment of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. 2. Cardialysis Clinical Trials Management and Core Laboratories, Rotterdam, The Netherlands. 3. Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands. 4. Department of Biomedical Imaging and Image Guided Therapy, Medical University Vienna, Vienna, Austria. 5. The Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil. 6. Hospital Israelita Albert Einstein, São Paulo, Brazil. 7. 3mensio Medical Imaging BV, Bilthoven, The Netherlands. 8. Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. 9. Department of Cardiothoracic Surgery, University Hospital of Zurich, Zurich, Switzerland. 10. Cardiovascular Science Division of the NHLI within Imperial, College of Science, Technology and Medicine, London, UK.
Abstract
AIMS: Transcatheter mitral valve replacement (TMVR) provides definitive valve replacement through a minimally invasive procedure. In the setting of TMVR, it remains unclear how relevant the differences between different mitral annular (MA) diameters are. We sought to define a simplified and reproducible method to describe the MA size. METHODS AND RESULTS: Using cardiac computed tomography angiography (CTA) studies of 47 patients, 3D MA perimeter (P3D) was annotated. The aorto-mitral continuity was excluded from MA contour either by manual annotation (yielding a saddle-shape model) or by simple truncation at the medial and lateral trigones (yielding a D-shape model). The method of the least squares was used to generate the projected MA area (Aproj) and perimeter (Pproj). Intercommissural (IC) and septolateral (SL) diameters, Dmean = (IC diameter + SL diameter)/2, area-derived diameter (DArea = 2 x √(A/π)) and perimeter-derived diameter (DPerimeter = P/π) were measured. MA eccentricity, height, and calcification (MAC) were assessed. Thirty studies were re-read by the same and by another observer to test intra- and inter-observer reproducibility. Patients (age, 75 ± 12 years, 66% males) had a wide range of mitral regurgitation severity (none-trace in 8%, mild in 55%, moderate-severe in 37%), MA size (area: 5-16 cm2), eccentricity (-8-52%), and height (3-11 mm). MAC was seen in 11 cases, in whom MAC arc occupied 26 ± 20% of the MA circumference. DArea (36.0 ± 4.0 mm) and DPerimeter (37.1 ± 3.8 mm) correlated strongly (R2 = 0.97) and were not significantly different (P = 0.15). The IC (39.3 ± 4.6 mm) and the SL (31.4 ± 4.5 mm) diameters were significantly different from DArea (P < 0.001) while Dmean (35.4 ± 4.0 mm) was not (P = 0.5). The correlation of DArea was stronger with Dmean (R2 = 0.96) than with IC and SL diameters (R2 = 0.69 and 0.76, respectively). The average difference between DArea and Dmean was +0.6 mm and the 95% limits of agreement were 2.1 and -0.9 mm. Similar results were found when the D-shape model was applied. All MA diameters showed good reproducibility with high intraclass correlation coefficient (0.93-0.98), small average bias (0.37-1.1 mm), and low coefficient of variation (3-7%) for intra- and inter-observer comparisons. Reproducibility of DArea was lower in patients with MAC. CONCLUSION: MA sizing by CTA is readily feasible and reproducible. Dmean is a simple index that can be used to infer the effective MA size. Published on behalf of the European Society of Cardiology. All rights reserved.
AIMS: Transcatheter mitral valve replacement (TMVR) provides definitive valve replacement through a minimally invasive procedure. In the setting of TMVR, it remains unclear how relevant the differences between different mitral annular (MA) diameters are. We sought to define a simplified and reproducible method to describe the MA size. METHODS AND RESULTS: Using cardiac computed tomography angiography (CTA) studies of 47 patients, 3D MA perimeter (P3D) was annotated. The aorto-mitral continuity was excluded from MA contour either by manual annotation (yielding a saddle-shape model) or by simple truncation at the medial and lateral trigones (yielding a D-shape model). The method of the least squares was used to generate the projected MA area (Aproj) and perimeter (Pproj). Intercommissural (IC) and septolateral (SL) diameters, Dmean = (IC diameter + SL diameter)/2, area-derived diameter (DArea = 2 x √(A/π)) and perimeter-derived diameter (DPerimeter = P/π) were measured. MA eccentricity, height, and calcification (MAC) were assessed. Thirty studies were re-read by the same and by another observer to test intra- and inter-observer reproducibility. Patients (age, 75 ± 12 years, 66% males) had a wide range of mitral regurgitation severity (none-trace in 8%, mild in 55%, moderate-severe in 37%), MA size (area: 5-16 cm2), eccentricity (-8-52%), and height (3-11 mm). MAC was seen in 11 cases, in whom MAC arc occupied 26 ± 20% of the MA circumference. DArea (36.0 ± 4.0 mm) and DPerimeter (37.1 ± 3.8 mm) correlated strongly (R2 = 0.97) and were not significantly different (P = 0.15). The IC (39.3 ± 4.6 mm) and the SL (31.4 ± 4.5 mm) diameters were significantly different from DArea (P < 0.001) while Dmean (35.4 ± 4.0 mm) was not (P = 0.5). The correlation of DArea was stronger with Dmean (R2 = 0.96) than with IC and SL diameters (R2 = 0.69 and 0.76, respectively). The average difference between DArea and Dmean was +0.6 mm and the 95% limits of agreement were 2.1 and -0.9 mm. Similar results were found when the D-shape model was applied. All MA diameters showed good reproducibility with high intraclass correlation coefficient (0.93-0.98), small average bias (0.37-1.1 mm), and low coefficient of variation (3-7%) for intra- and inter-observer comparisons. Reproducibility of DArea was lower in patients with MAC. CONCLUSION: MA sizing by CTA is readily feasible and reproducible. Dmean is a simple index that can be used to infer the effective MA size. Published on behalf of the European Society of Cardiology. All rights reserved.