The normal aortic valve leaflets effective height in pediatric patients: A guide to aortic valve repair

Abstract

Central MessageThis study determines a normogram to predict the normal aortic valve cusps effective height according to the body surface area in pediatric patients.See Commentaries on pages 138 and 140. This study determines a normogram to predict the normal aortic valve cusps effective height according to the body surface area in pediatric patients. See Commentaries on pages 138 and 140. Aortic valve (AV) repair is an attractive option in pediatric patients because it avoids the long-term risk of anticoagulation, allows growth, and postpones AV replacement. In the past decade, favorable results in the adult patients and the emergence of a systematic approach to the AV partly explain the 3-fold increase in pediatric AV repairs.1Bouhout I. Ba P.S. El-Hamamsy I. Poirier N. Aortic valve interventions in pediatric patients.Semin Thorac Cardiovasc Surg. 2019; 31: 277-287Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar The effective height (eH) is defined as the difference between the central free margins and the atrioventricular junction and is used as predictor of valve repair durability in adult patients.2Bierbach B.O. Aicher D. Issa O.A. Bomberg H. Gräber S. Glombitza P. et al.Aortic root and cusp configuration determine aortic valve function.Eur J Cardiothorac Surg. 2010; 38: 400-406Crossref PubMed Scopus (103) Google Scholar,3Aicher D. Kunihara T. Abou Issa O. Brittner B. Graber S. Schafers H.J. Valve configuration determines long-term results after repair of the bicuspid aortic valve.Circulation. 2011; 123: 178-185Crossref PubMed Scopus (240) Google Scholar Indeed, a postoperative eH <9 mm was associated with a higher risk of AV reintervention in the long-term. The normal value of this parameter remains unknown in pediatric populations. All the normal transthoracic echocardiograms performed in paediatric patients between January and July 2018 at our institution were considered for this study. Upon additional review, echocardiograms from patients with aortic regurgitation (trace or mild) or other cardiac lesions were excluded (n = 92). A total of 714 echocardiograms were included in the present analysis. Nine (1.2%) patients had a bicuspid AV. The echocardiogram measurements were all performed by 2 accredited cardiologists retrospectively using the long-axis view in 2-dimensional echocardiograms. The primary end point was the eH, which was defined as the distance between the free edge of individual cusp and the plane of the annulus in end-diastole. The secondary end point was the geometric height, which was defined as the length of individual cusp in end-diastole (Figure 1). The study was approved by our institutional review board and a waiver of consent was obtained. Continuous variables are presented as means, medians, standard deviations, and range as appropriate. Categorical variables are expressed as frequencies and percentages. To examine the relationships between parameters of body size and each of the echocardiographic variables, multiple models were tested (ie, linear, logarithmic, exponential, and square-root equations). Among the models that satisfied the assumption of homoscedasticity, the model with the highest R2 value and normality of residuals was considered to provide the best fit. Body surface area (BSA), height, and weight were used as independent variables in each model. The median age of patients was 6.2 years (range, 3 days-17.7 years) and 340 (48%) were female. One hundred fifteen (16%) were infants (aged <1 year), 413 (58%) were children (aged 1-12 years), and 186 (26%) were adolescents (aged 12-18 years). The median BSA, height, and weight were 0.82 m2 (range, 0.1-2.32 m2), 117 cm (range, 35-186 cm), and 21 kg (range, 1-100 kg), respectively. A logarithmic equation resulted in the best fit and was used for all the correlations. The eH correlated with BSA (R2 = 0.52 and R = 0.72). Similarly, the eH correlated with the height and weight (R2 = 0.54 and R = 0.73; R2 = 0.51 and R = 0.71). The geometric height (R2 = 0.81 and R = 0.90) correlated with the BSA. A chart of normal values has been derived from these models and presented in the Table 1 and Figure 2.Table 1Leaflet and root predicted dimensions according to the body surface areaBody surface area (m2)Effective height (mm)Geometric height (mm)0.24 ± 18 ± 10.35 ± 110 ± 10.46 ± 111 ± 10.56 ± 112 ± 10.67 ± 113 ± 10.7-0.87 ± 114 ± 10.97 ± 115 ± 11.07 ± 116 ± 11.1-1.28 ± 116 ± 11.3-1.68 ± 117 ± 11.78 ± 118 ± 11.8-2.09 ± 119 ± 1Values are presented as mean ± standard deviation. Open table in a new tab Values are presented as mean ± standard deviation. In adults, achieving a normal eH (>9 mm) after AV repair results in a better long-term valve function.2Bierbach B.O. Aicher D. Issa O.A. Bomberg H. Gräber S. Glombitza P. et al.Aortic root and cusp configuration determine aortic valve function.Eur J Cardiothorac Surg. 2010; 38: 400-406Crossref PubMed Scopus (103) Google Scholar,3Aicher D. Kunihara T. Abou Issa O. Brittner B. Graber S. Schafers H.J. Valve configuration determines long-term results after repair of the bicuspid aortic valve.Circulation. 2011; 123: 178-185Crossref PubMed Scopus (240) Google Scholar This measure is useful in accessing residual cusp prolapse and can be accessed intraoperatively using an adjustable Schäfers’ caliper (Video 1).4Schafers H.J. Bierbach B. Aicher D. A new approach to the assessment of aortic cusp geometry.J Thorac Cardiovasc Surg. 2006; 132: 436-438Abstract Full Text Full Text PDF PubMed Scopus (200) Google Scholar Therefore, the creation of a nomogram to evaluate cusp eH in pediatric patients and aiming for an optimal eH intraoperatively may improve AV repair durability in pediatric patients. This is all the more important because congenital AV disease can present with a varying degrees of cusp retraction and thickening, which often necessitate complex repair and the use a patch leaflet extension. The present study is limited by the use of 2-dimensional measures, small number of competent bicuspid AV included and the retrospective study design. The present study report measures in a normal population and a validation study is needed to assess the value of this chart in predicting long-term AV repair durability. https://www.jtcvstechniques.org/cms/asset/40a7c14d-180d-4c6e-a12d-796f26630d12/mmc1.mp4Loading ... Download .mp4 (43.78 MB) Help with .mp4 files Video 1Aortic valve repair of a truncal quadricuspid valve and measure of the effective height using Schafers’ caliper. Video available at: https://www.jtcvs.org/article/S2666-2507(21)00374-6/fulltext. Download .jpg (.12 MB) Help with files Video 1Aortic valve repair of a truncal quadricuspid valve and measure of the effective height using Schafers’ caliper. Video available at: https://www.jtcvs.org/article/S2666-2507(21)00374-6/fulltext.

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