Background: In this study, we examined and compared ex vivo mechanical properties of aortic walls in patients with bicuspid (BAV) and tricuspid (TAV) aortic valve aortopathy to investigate if the anatomical peculiarities in the BAV group are related to an increased frailty of the aortic wall and, therefore, if a different surgical cutoff point for ascending aortic replacement could be reasonable in such patients. Methods: Ultimate stress tests were performed on fresh aortic wall specimens harvested during elective aortic surgery in BAV (n. 33) and TAV (n. 77) patients. Three mechanical parameters were evaluated at the failure point, under both longitudinal and circumferential forces: the peak strain (Pstr), peak stress (PS), and maximum elastic modulus (EM). The relationships between the three mechanical parameters and preoperative characteristics were evaluated, with a special focus on evaluating potential risk factors for severely impaired mechanical properties, cumulatively and comparatively (BAV vs. TAV groups). Results: The patient populations were inhomogeneous, as BAV patients reached surgical indication, according to the maximum aortic dilatation, at a younger age (58 ± 15 vs. 64 ± 13; p = 0.0294). The extent of the maximum aortic dilatation was, conversely, similar in the two groups (52 ± 4 vs. 54 ± 7; p = 0.2331), as well as the incidences of different phenotypes of aortic dilatation (with the ascending aorta phenotype being the most frequent in 81% and 66% of the BAV and TAV patients, respectively (p = 0.1134). Cumulatively, the mechanical properties of the aortic wall were influenced mainly by the orientation of the force applied, as both PS and EM were impaired under longitudinal stress. An age of >66 and a maximum dilatation of >52 mm were shown to predict severe Pstr reduction in the overall population. Comparative analysis revealed a trend of increased mechanical properties in the BAV group, regardless of the position, the force orientation, and the phenotype of the aortic dilatation. Conclusions: BAV aortopathy is not correlated with impaired mechanical properties of the aortic wall as such. Different surgical cutoff points for BAV aortopathy, therefore, seem to be unjustified. An age of >66 and a maximum aortic dilatation of >52 mm, however, seem to significantly influence the mechanical properties of the aortic wall in both groups. These findings, therefore, could suggest the need for more accurate monitoring and evaluation in such conditions.

Background: Mock circulatory loops (MCLs) are benchtop experimental platforms that reproduce key features of the human cardiovascular system, providing a safe, controlled, and reproducible environment for haemodynamic investigation. This scoping review aims to systematically map the current landscape of MCLs used for aortic simulation and identify major areas of application. Methods: A systematic search of PubMed, Scopus, and Web of Science identified original studies employing MCLs for aortic simulation. Eligible studies were categorized into predefined themes: (I) (bio)mechanical aortic characterization, (II) hemodynamics, (III) device testing, (IV) diagnostics, and (V) training. Data on MCL configurations, aortic models, and study objectives were synthesized narratively. Results: Eighty-four studies met the inclusion criteria. Twenty-five investigated aortic biomechanics, 23 hemodynamics, 22 device or product testing, 13 validated diagnostic imaging techniques, and one training application. Models included porcine (n = 22), human cadaveric (n = 7), canine (n = 1), ovine (n = 1), bovine (n = 1), and 3D-printed or molded aortic phantoms (n = 55). MCLs were employed to study parameters such as aortic stiffness, flow dynamics, dissection propagation, endoleaks, imaging accuracy, and device performance. Conclusions: This review provides a comprehensive overview of MCL applications in aortic research. MCLs represent a versatile pre-clinical platform for studying aortic pathophysiology and testing endovascular therapies under controlled conditions. Standardized reporting frameworks are now required to improve reproducibility and accelerate translation to patient-specific planning.

Background: The ex vivo evaluation of the aortic wall aims to identify potential risk factors predictive of acute aortic syndrome. The comparison of aortic wall properties in patients with bicuspid aortic disease versus those with tricuspid aortic disease has been the subject of many studies. However, the heterogeneity of aortic wall characteristics in individual patients has never been thoroughly investigated. In this study, we focused on comparing the heterogeneity of aortic wall characteristics in patients with bicuspid (BAV) and tricuspid (TAV) aortic valve disease. Materials and Methods: Out of 113 patients enrolled in our cumulative study on the ex-vivo evaluation of the aortic wall, in patients with dilated ascending aorta, 56 patients with >3 specimens taken from the anterior wall were selected for the present study. The heterogeneity of anatomical characteristics (aortic wall thickness) was assessed by measuring the coefficient of variability (cV). In 35 patients, furthermore, mechanical (uniaxial ultimate stress–strain test) characteristics heterogeneity was also evaluated. Intra-patient mechanical and anatomical variability was then compared between the BAV and TAV groups. Results: Heterogeneity of aortic wall thickness was significantly less important compared to heterogeneity of mechanical properties: peak strain (Pstr p = 0.0042), peak stress (PS p = 0.001) and maximum elastic modulus (EM p = 0.001). Only EM heterogeneity was significantly reverse-correlated to patient’s age (p = 0.0005), and this correlation was peculiar for patients with BAV. In BAV patients, furthermore, age > 66 was associated with a significantly superior EM heterogeneity (p = 0.008). A direct comparison of anatomical and mechanical intra-patient variability between BAV and TAV groups, however, did not show significant differences. Discussion: Our study clearly demonstrates that the anatomical and mechanical characteristics of the aortic wall in patients with aortic dilation are not homogeneous. The heterogeneity of aortic wall thickness appears to be less significant than that of mechanical properties, thus confirming a limited correlation between anatomical and mechanical characteristics. The comparison between the BAV and TAV groups revealed limited peculiarities, further suggesting a preservation of the mechanical properties of the aortic wall in patients with bicuspid aortic disease and, therefore, without a peculiar mechanical properties-related increased risk of acute aortic syndrome.

Open surgical repair is the gold standard for ascending aortic (AA) diseases, but the need to manage high-risk patients has promoted interest in endovascular alternatives. However, their application in the AA remains limited, in part because suitable experimental models that accurately reproduce human geometry and biomechanics are lacking. We developed and validated a novel ex-vivo porcine model that replicates the human AA by suturing the AA of a first specimen with an additional ascending and arch segment from a second aorta. Twelve models were prepared and tested in a mock circulatory loop under physiological pressure and flow conditions. Geometrical similarity to human anatomy, mechanical behaviour, and in-vitro perfusion feasibility were evaluated by measuring length, diameter, distensibility, and pulse wave velocity (PWV). The procedure extended the native porcine AA + arch from 5.8 ± 0.4 cm to 11.6 ± 1.1 cm, matching the human length (∼12.4 cm), while diameters remained within the physiological human range (27-36 mm). Despite a local restriction at the suture site, distensibility (2.3-2.8 × 10⁻³ mmHg⁻¹) and PWV (3.8 ± 0.6 m/s) values were comparable to native porcine aortas suggesting preserved biomechanics, and differences from typical human values reflected expected interspecies variability rather than model artifacts. The extended porcine AA model accurately reproduces human AA geometry and mechanical response without compromising tissue integrity. The model provides a practical and reproducibleex-vivoplatform forin-vitro testing and development of novel endovascular devices targeting human AA, bridging the gap between bench-top validation and preclinical evaluation.

In recent years, percutaneous procedures are gradually replacing open heart surgery for the treatment of tricuspid valve pathological conditions deploying prosthetic devices (i.e., stent-graft) within the proximal portion of the cava veins. Nevertheless, since there is no comprehensive mechanical characterization of the venous district, the devices exploited in these procedures are very similar to the ones exploited in aortic treatment, involving possible critical periprocedural complications. According to the international standards adopted for the design of novel vascular devices, this study presents an experimental set-up to investigate the biomechanics of fifteen porcine cava veins with the development of a semi-automatic protocol for compliance testing. During the tests, 2D echo images of the vessel lumen are acquired for different steps within a pressure range of 5-20 mmHg. The acquired pressure-diameter curves of the samples are then derived by a polynomial function, furthermore, the compliance values are obtained using the corresponding equations as well. The results demonstrate that the cava vein exhibits a hyperelastic behavior, with a nonlinear relationship between pressure and diameter. At low pressures, the veins demonstrate high compliance and reduced stiffness (11.54 ± 4.76 kPa). On the contrary, when pressures exceed the normal physiological range (i.e., greater than 10 mmHg), the veins become stiffer (294.70 ± 233.00 kPa). The developed set-up, based on an ex-vivo porcine model, proved to be a robust tool for the assessment of vein biomechanics and for preclinical benchmarking of novel venous endovascular devices.