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Background: Aortic-valve-stenosis (AS) is a frequent degenerative valvular-disease and carries dismal outcome under-medical-treatment. Transvalvular pressure gradient reflects severity of the valve-disease but is highly dependent on flow-conditions and on other valvular/aortic characteristics. Alternatively, aortic-valve-area (AVA) represents a measure of aortic-valve lesion severity conceptually essential and practically widely-recognized but exhibits multiple-limitations., Methods: We analyzed the 4D multi-detector computed tomography(MDCT) of 20 randomly selected patients with severe AS. For each-patient, we generated the 3D-model of the valve and of its calcifications, and we computed the anatomical AVA accounting for the 3D-morphology of the leaflets in three-different-ways. Finally, we compared our results vs. Doppler-based AVA E measurements and vs. 2D-planimetric AVA-measurements., Results: 3D-reconstruction and identification of the cusps were successful in 90% of the cases. The calcification patterns where highly-variable over patients, ranging from multiple small deposits to wide and c-shaped deposits running from commissure-to-commissure. AVA E was 82 ± 15 mm 2 . When segmenting 18 image planes, AVA Tight , AVA Proj-Ann , AVA Proj-Tip and their average AVA Ave were equal to 80 ± 16, 88 ± 20, 93 ± 21 and 87 ± 19 mm 2 , respectively, while AVA Plan was equal to 143 ± 50 mm 2 . Linear-regression of the three measurements vs. AVA E yielded regression slopes equal to 1.26, 1.13 and 0.93 for AVA Proj-Ann , AVA Proj-Tip and AVA Tight , respectively. The respective Pearson-coefficients were 0.85,0.86 and 0.90. Conversely, when comparing AVA Plan vs. AVA E , linear regression yielded a slope of 1.73 and a Pearson coefficient of 0.53., Conclusions: We described a new-method to obtain a set of flow-independent quantifications that complement pressure gradient measurements and combine the advantages of previously proposed methods, while bypassing the corresponding-limitations., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier B.V.)

In transcatheter aortic valve implantation (TAVI), final device position may be affected by device interaction with the whole aortic landing zone (LZ) extending to ascending aorta. We investigated the impact of aortic LZ curvature and angulation on TAVI implantation depth, comparing short-frame balloon-expanding (BE) and long-frame self-expanding (SE) devices. Patients (n = 202) treated with BE or SE devices were matched based on one-to-one propensity score. Primary endpoint was the mismatch between the intended (H Pre ) and the final (H Post ) implantation depth. LZ curvature and angulation were calculated based on the aortic centerline trajectory available from pre-TAVI computed tomography. Total LZ curvature ( k L Z , t o t ) and LZ angulation distal to aortic annulus ( α L Z , D i s t a l ) were greater in the SE compared to the BE group (P < 0.001 for both). In the BE group, H Post was significantly higher than H Pre at both cusps (P < 0.001). In the SE group, H Post was significantly deeper than H Pre only at the left coronary cusp (P = 0.013). At multivariate analysis, α L Z , D i s t a l was the only independent predictor (OR = 1.11, P = 0.002) of deeper final implantation depth with a cut-off value of 17.8°. Aortic LZ curvature and angulation significantly affected final TAVI implantation depth, especially in high stent-frame SE devices reporting, upon complete release, deeper implantation depth with respect to the intended one., (© 2024. The Author(s).)

In Sleeve procedure, the leaflets-sinus unit is maintained. We hypothesized that this feature partially preserves aortic root (AR) dynamics and leaflets kinematics and limits tensions in the leaflets. We tested our hypothesis based on in vivo and computational assessment of leaflets and AR dynamics. AR and aortic leaflet kinematics was assessed by transthoracic echocardiography in 10 patients treated with the Sleeve procedure and in 10 healthy patients. Numerical calculations with the Finite Element Method were performed to support the analysis of the clinical results and provide a better understanding of the behavior of the AR treated via the Sleeve procedure. Echocardiographic evidence showed that AR expansion in the Sleeve group was partially preserved as compared to the Control group (2.9 ± 2.5% vs 7.7 ± 6.3%, P = 0.038) and of the sinotubular junction (2.9 ± 1.5% vs 7.3 ± 3.8%, P = 0.003), and significantly preserved at the Valsalva sinuses level (6.7 ± 2.6% vs 9.5 ± 4.3%) with not statistically significant differences (P = 0.11). In none of the cardiac phases, differences in aortic valve leaflets kinematics were measured between the 2 groups; computational results were rather consistent with this evidence. Computational results well matched echocardiographic evidences, allowing for their mechanistic interpretation. Near-normal opening and closing characteristics can be accomplished by a technique that preserves the shape and the dynamics of the Valsalva sinuses. Whether the substantial preservation of the AR distensibility and leaflets kinematics observed in this study will favorably affect long-term valve durability it remains to be ascertained., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Transcatheter aortic valve implantation (TAVI) can treat symptomatic patients with calcific aortic stenosis. However, the severity and distribution of the calcification of valve leaflets can impair the TAVI efficacy. Here we tackle this issue from a biomechanical standpoint, by finite element simulation of a widely adopted balloon-expandable TAVI in three models representing the aortic root with different scenarios of calcific aortic stenosis. We developed a modeling approach realistically accounting for aortic root pressurization and complex anatomy, detailed calcification patterns, and for the actual stent deployment through balloon-expansion. Numerical results highlighted the dependency on the specific calcification pattern of the "dog-boning" of the stent. Also, local stent distortions were associated with leaflet calcifications, and led to localized gaps between the TAVI stent and the aortic tissues, with potential implications in terms of paravalvular leakage. High stresses were found on calcium deposits, which may be a risk factor for stroke; their magnitude and the extent of the affected regions substantially increased for the case of an "arc-shaped" calcification, running from commissure to commissure. Moreover, high stresses due to the interaction between the aortic wall and the leaflet calcifications were computed in the annular region, suggesting an increased risk for annular damage. Our analyses suggest a relation between the alteration of the stresses in the native anatomical components and prosthetic implant with the presence and distribution of relevant calcifications. This alteration is dependent on the patient-specific features of the calcific aortic stenosis and may be a relevant indicator of suboptimal TAVI results., (Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: Bicuspid aortic valve disease is heterogeneous with respect to valve morphology and aortopathy risk. This study searched for early imaging predictors of aortopathy in patients with a bicuspid aortic valve with right-left coronary cusp fusion, the most common morphotype., Methods: Time-resolved magnetic resonance imaging was performed in 36 subjects with nonstenotic, nonregurgitant bicuspid aortic valves and nondilated aortas and in 10 healthy controls with tricuspid aortic valves. Sinus dimensions (diameter, width, and height), ascending tract diameters, and wall strain were measured for each sinus/leaflet unit and corresponding ascending tract area to account for asymmetries. A novel parameter, "cusp opening angle," measured the degree of valve leaflet alignment to outflow axis in systole, quantifying cusp motility. Phase-contrast magnetic resonance imaging and computational fluid dynamic models assessed flow patterns. Aortic growth rate was estimated over a follow-up period ranging from 9 to 84 months., Results: The expected restriction of bicuspid aortic valve opening (conjoint cusp opening angle, 62°±5° vs 76°±3° for nonfused leaflet and 75°±3° for tricuspid aortic valve cusps; P<.001) was confirmed, and the introduced parameter reproducibly quantified this phenomenon. Phase-contrast magnetic resonance imaging demonstrated systolic flow deflection toward the right, affecting the right anterolateral ascending wall. Computational models confirmed that restricted cusp motion alone is sufficient to cause the observed flow pattern. Ascending tract wall strain was not circumferentially homogeneous in bicuspid aortic valves. In multivariable analyses, the conjoint cusp opening angle independently predicted ascending aorta diameters and growth rate (P<.001)., Conclusions: In the bicuspid aortic valve commonly defined as normofunctional by echocardiographic criteria, restricted systolic conjoint cusp motion causes flow deflection. The novel measurement introduced can quantify restricted cusp opening, possibly assuming prognostic importance., (Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Recently, the neo-chordae technique (NCT) was proposed to stabilize the surgical correction of isolated aortic valve (AV) prolapse. Neo-chordae are inserted into the corrected leaflet to drive its closure by minimal tensions and prevent relapses. In a previous in vitro study we analysed the NCT effects on healthy aortic roots (ARs). Here we extend that analysis via finite element models (FEMs). After successfully replicating the experimental conditions for validation purposes, we modified our AR FEM, obtaining a continent AV with minor isolated prolapse, thus representing a realistic clinical scenario. We then simulated the NCT, and systematically assessed the acute effects of changing neo-chordae length, opening angle, asymmetry and insertion on the aorta. In the baseline configuration the NCT restored physiological AV dynamics and coaptation, without inducing abnormal leaflet stresses. This outcome was notably sensitive only to neo-chordae length, suggesting that the NCT is a potentially easy-to-standardize technique. However, this parameter is crucial: major shortenings (6 mm) prevent coaptation and increase leaflet stresses by 359 kPa, beyond the yield limit. Minor shortenings (2-4 mm) only induce a negligible stress increase and mild leaflet tethering, which however may hamper the long-term surgical outcome.

Objective: Aortic interleaflets triangles annuloplasty (AITA) reduces interleaflet triangles' circumferential extent through properly placed sutures. To achieve aortic root functional unit (ARFU) stabilization, we aimed at quantifying the effect of suture extent (SE) on aortic valve function and at finding general optimization criteria., Methods: A previously published ARFU finite element model was modified to simulate ARFU dilation and AITA, systematically varying the SE and quantifying the corresponding regurgitant orifice (RO), leaflets co-aptation area (CA) and annular diameter (D(a)). Computational outcomes were tested by comparison with postoperative virtual basal ring echo data of 105 successfully corrected ARFUs., Results: According to our finite element simulations of AITA, RA and CA depended linearly on SE, through a relationship that predicted optimal surgical results when SE was equal to 48% of the interleaflet triangle height (ITH). Follow-up data showed that, after AITA, ARFU diameter decreased from 23.4 ± 3.93 to 20.1 ± 1.8mm, (p<0.05) at the annulus, from 41.53 ± 6.347 to 38.2 ± 4.0 mm, (p<0.01) at the sinuses, and from 41.3 ± 6.47 to 35.25 ± 5.95 mm (p=ns) at the sinotubular junction (STJ). The mean ITH was 11.18 ± 1.74 mm and the mean SE predicted by our model was 5.34 ± 0.6mm, that is, 47.76% of the ITH, comparable to 48% of the computational model. Leaflet co-aptation length (CL) increased from 2.73 ± 1.25 to 7.56 ± 2.36 mm (p<0.001), while the CA evaluated via finite element modeling changed from 8% to 48%., Conclusions: So far, the AITA seems to be a valuable technique to increase leaflet CL in aortic valve repair and in silico models seem to be able to predict the principles of the phenomena but not the individual complexity., (Copyright © 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.)

Objective: Congenital bicuspid aortic valves frequently cause aortic stenosis or regurgitation. Improved understanding of valve and root biomechanics is needed to achieve advancements in surgical repair techniques. By using imaging-derived data, finite element models were developed to quantify aortic valve and root biomechanical alterations associated with bicuspid geometry., Methods: A dynamic 3-dimensional finite element model of the aortic root with a bicuspid aortic valve (type 1 right/left) was developed. The model's geometry was based on measurements from 2-dimensional magnetic resonance images acquired in 8 normotensive and otherwise healthy subjects with echocardiographically normal function of their bicuspid aortic valves. Numeric results were compared with those obtained from our previous model representing the normal root with a tricuspid aortic valve. The effects of raphe thickening on valve kinematics and stresses were also evaluated., Results: During systole, the bicuspid valve opened asymmetrically compared with the normal valve, resulting in an elliptic shape of its orifice. During diastole, the conjoint cusp occluded a larger proportion of the valve orifice and leaflet bending was altered, although competence was preserved. The bicuspid model presented higher stresses compared with the tricuspid model, particularly in the central basal region of the conjoint cusp (+800%). The presence of a raphe partially reduced stress in this region but increased stress in the other cusp., Conclusions: Aortic valve function is altered in clinically normally functioning bicuspid aortic valves. Bicuspid geometry per se entails abnormal leaflet stress. The stress location suggests that leaflet stress may play a role in tissue remodeling at the raphe region and in early leaflet degeneration., (Copyright © 2010 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

David and Yacoub sparing techniques are the most common procedures adopted for the surgical correction of aortic root aneurysms. These surgical procedures entail the replacement of the sinuses of Valsalva with a synthetic graft, inside which the cusps are re-suspended. Root replacement by a synthetic graft may result in altered valve behaviour both in terms of coaptation and stress distribution, thus leading to the failure of the correction. A finite element approach was used to investigate this phenomenon; four 3D models of the aortic root were developed to simulate the root in physiological, pathological and post-operative conditions after the two different surgical procedures. The physiological 3D geometrical model was developed on the basis of anatomical data obtained from echocardiographic images; it was then modified to obtain the pathological and post-operative models. The effectiveness of both techniques was assessed by comparison with the first two simulated conditions, in terms of stresses acting on the root, leaflet coaptation and interaction between leaflets and the graft during valve opening. Results show that both sparing techniques are able to restore aortic valve coaptation and to reduce stresses induced by the initial root dilation. Nonetheless, both techniques lead to altered leaflet kinematics, with more evident alterations after David repair.

A 3-D model of the aortic root was developed consisting of aortic valve, sinus of Valsalva and aortic duct. Through finite element modeling, the mechanical behavior of the valve was investigated simulating four different configurations: physiological (baseline), aneurysmatic and corrected with two different sparing techniques, named after David and Yacoub, respectively. These surgical procedures imply the replacement of the sinus of Valsalva with a synthetic graft, inside which the cusps are resuspended. The final goal of this study consisted in the assessment of the mechanical effects of sinuses aneurysm on the whole root, as well as the effectiveness of the two aforementioned techniques in restoring valve functionality and normal stress values on the root substructures. Based on the assumption of three-leaflet symmetry, only one third of the aortic root was modeled. Two cardiac cycles were simulated and the mechanical behavior of the aortic root was evaluated in terms of stress pattern, contact pressure and contact areas observed during leaflets coaptation and when contact between the leaflet and the graft occurs. Both the sparing techniques are able to restore coaptation of the aortic valve, but for the David procedure, contact between the leaflet and the graft wall was detected. [ABSTRACT FROM AUTHOR]