Intravascular lithotripsy in the treatment of coronary artery calcification in a high-risk real world population.

BACKGROUND: The DISRUPT-CAD study series demonstrated feasibility and safety of intravascular lithotripsy (IVL) in selected patients, but applicability across a broad range of clinical scenarios remains unclear. AIMS: This study aims to evaluate the procedural and clinical outcomes of IVL in a high-risk real-world cohort, compared to a regulatory approval cohort. METHODS: Consecutive patients treated with IVL and percutaneous coronary intervention at our center from May 2016 to April 2020 were included. Comparison was made between those enrolled in the DISRUPT-CAD series of studies to those with calcified lesions but an exclusion criteria. RESULTS: Among 177 patients treated with IVL, 142 were excluded from regulatory trials due to acute coronary syndrome presentation (47.2%), left ventricular ejection fraction <40% (22.5%), chronic renal failure (12.0%), or use of mechanical circulatory support (8.5%). This clinical cohort had a higher SYNTAX score (22.6 ± 12.1 vs. 17.4 ± 9.9, p = 0.019), and more treated ACC/AHA C lesions (56.3% vs. 37.1%, p = 0.042). Rates of device success (93.7% vs. 100.0%, p = 0.208), procedural success (96.5% vs. 100.0%, p = 0.585), and minimal lumen area gain (221.2 ± 93.7% vs. 198.6 ± 152.0%, p = 0.807) were similar in both groups. The DISRUPT-CAD cohort had no in-hospital mortality, 30-day major adverse cardiac events (MACE), or 30-day target vessel revascularization (TVR). The clinical cohort had an in-hospital mortality of 4.2%, 30-day MACE of 7.8%, and 30-day TVR of 1.5%. There was no difference in 12-month TVR (2.9% vs. 2.2%; p = 0.825). Twelve-month MACE was higher in the clinical cohort (21.1% vs. 8.6%, p = 0.03). CONCLUSION: IVL use remains associated with high clinical efficacy, procedural success, and low complication rates in a real-world population previously excluded from regulatory approving trials.

Metal-based micro and nanosized pollutant in marine organisms: What can we learn from a combined atomic force microscopy-scanning electron microscopy study.

Atomic force microscopy (AFM) is a consolidated technique for the study of biological systems, usually ex vivo or in culture, under different experimental conditions. Yet, the diffusion of the technique in the scientific context of histology is still rather slow and limited. In the present work, we demonstrate the potential of AFM, in terms of morphological and nanomechanical imaging, to study the effects of nano- and micro-sized metallic pollutants in living biological systems. As a model, we investigated marine molluscs (Mytilus galloprovincialis) grown in the Adriatic Sea. We characterized histological sections from two organs (gonads and digestive glands) of molluscs collected during several surveys at different growth time and distance from gas extraction platforms. We evaluated the effects of nano-pollutants mostly on the local tissue structure by combining AFM microscopy with scanning electron microscopy (SEM). Furthermore, the AFM images allowed evidencing the presence of nano- or micro-sized structures that exhibit different nanomechanical properties compared to the rest of the tissue. The results demonstrate how coupling AFM and SEM analysis can provide an effective procedure to evaluate the morphological alterations produced by the exposure to exogenous nano-pollutants in tissue and constitute a promising way to reveal basic mechanisms mediating the cytotoxicity of specific exogenous pollutants ingested by edible organisms.

3D Bioprinting in Skeletal Muscle Tissue Engineering.

Skeletal muscle tissue engineering (SMTE) aims at repairing defective skeletal muscles. Until now, numerous developments are made in SMTE; however, it is still challenging to recapitulate the complexity of muscles with current methods of fabrication. Here, after a brief description of the anatomy of skeletal muscle and a short state-of-the-art on developments made in SMTE with "conventional methods," the use of 3D bioprinting as a new tool for SMTE is in focus. The current bioprinting methods are discussed, and an overview of the bioink formulations and properties used in 3D bioprinting is provided. Finally, different advances made in SMTE by 3D bioprinting are highlighted, and future needs and a short perspective are provided.

Combination of biochemical and mechanical cues for tendon tissue engineering.

Tendinopathies negatively affect the life quality of millions of people in occupational and athletic settings, as well as the general population. Tendon healing is a slow process, often with insufficient results to restore complete endurance and functionality of the tissue. Tissue engineering, using tendon progenitors, artificial matrices and bioreactors for mechanical stimulation, could be an important approach for treating rips, fraying and tissue rupture. In our work, C3H10T1/2 murine fibroblast cell line was exposed to a combination of stimuli: a biochemical stimulus provided by Transforming Growth Factor Beta (TGF-ß) and Ascorbic Acid (AA); a three-dimensional environment represented by PEGylated-Fibrinogen (PEG-Fibrinogen) biomimetic matrix; and a mechanical induction exploiting a custom bioreactor applying uniaxial stretching. In vitro analyses by immunofluorescence and mechanical testing revealed that the proposed combined approach favours the organization of a three-dimensional tissue-like structure promoting a remarkable arrangement of the cells and the neo-extracellular matrix, reflecting into enhanced mechanical strength. The proposed method represents a novel approach for tendon tissue engineering, demonstrating how the combined effect of biochemical and mechanical stimuli ameliorates biological and mechanical properties of the artificial tissue compared to those obtained with single inducement.

Strategies and Outcomes of Repeat Mitral Valve Interventions after Failed MitraClip Therapy.

Percutaneous mitral valve repair (PMVR) with the MitraClip system (Abbott Vascular, Santa Clara, CA, USA) is a valid therapeutic option for patients with severe mitral regurgitation (MR) deemed to be at high or prohibitive surgical risk. Despite the reassuring data on efficacy and long-term durability of the procedure, the proportion of patients with residual or relapsing severe MR after MitraClip therapy is not negligible. In light of the detrimental prognostic impact of severe MR, repeat interventions are increasingly performed in clinical practice using different techniques. In high-risk settings, percutaneous procedures have proven to be effective and safe at reducing MR. Building on this, we sought to summarize the current landscape and clinical experience of reinterventions after failed MitraClip therapy, so as to assist physicians facing the clinical hurdle of proper treatment management after failed PMVR.

Could a functional artificial skeletal muscle be useful in muscle wasting?

PURPOSE OF REVIEW: Regardless of the underlying cause, skeletal muscle wasting is detrimental for a person's life quality, leading to impaired strength, locomotion, and physiological activity. Here, we propose a series of studies presenting tissue engineering-based approaches to reconstruct artificial muscle in vitro and in vivo. RECENT FINDINGS: Skeletal muscle tissue engineering is attracting more and more attention from scientists, clinicians, patients, and media, thanks to the promising results obtained in the last decade with animal models of muscle wasting. The use of novel and refined biomimetic scaffolds mimicking three-dimensional muscle environment, thus supporting cell survival and differentiation, in combination with well characterized myogenic stem/progenitor cells, revealed the noteworthy potential of these technologies for creating artificial skeletal muscle tissue. In vitro, the production of three-dimensional muscle structures offer the possibility to generate a drug-screening platform for patient-specific pharmacological treatment, opening new frontiers in the development of new compounds with specific therapeutic actions. In vivo, three-dimensional artificial muscle biomimetic constructs offer the possibility to replace, in part or entirely, wasted muscle by means of straight reconstruction and/or by enhancing endogenous regeneration. SUMMARY: Reports of tissue engineering approaches for artificial muscle building appeared in large numbers in the specialized press lately, advocating the suitability of this technology for human application upon scaling up and a near future applicability for medical care of muscle wasting. VIDEO ABSTRACT: http://links.lww.com/COCN/A9

Predictors of clinical outcomes after edge-to-edge percutaneous mitral valve repair.

BACKGROUND: There is limited information on the long-term outcomes and prognostic clinical predictors after edge-to-edge transcatheter mitral valve repair with the MitraClip system. METHODS: Consecutive patients with mitral regurgitation (MR) undergoing MitraClip therapy between October 2008 and November 2013 in 4 Italian centers were analyzed. The primary end point of interest was all-cause death. The secondary end point was the composite of all-cause death or rehospitalization for heart failure. RESULTS: A total of 304 patients were included, of which 79% had functional MR and 17% were in New York Heart Association functional class IV. Acute procedural success was obtained in 92% of cases, with no intraprocedural death. The cumulative incidences of all-cause death were 3.4%, 10.8%, and 18.6% at 30 days, 1 year, and 2 years, respectively. The corresponding incidences of the secondary end point were 4.4%, 22.0%, and 39.7%, respectively. In the Cox multivariate model, New York Heart Association functional class IV at baseline and ischemic MR etiology were found to significantly and independently predict both the primary and the secondary end point. A baseline, left ventricular end-systolic volume >110 mL was found to be an independent predictor of the secondary endpoint. Acute procedural success was independently associated with a lower risk of all-cause death and the combination of all-cause death or rehospitalization for heart failure at long-term follow-up. CONCLUSIONS: In a cohort of patients undergoing MitraClip therapy, those presenting at baseline with ischemic functional etiology, severely dilated ventricles, or advanced heart failure and those undergoing unsuccessful procedures carried the worst prognosis.

Gender-related clinical and echocardiographic outcomes at 30-day and 12-month follow up after MitraClip implantation in the GRASP registry.

OBJECTIVES: To assess the influence of patients' gender on the outcomes of percutaneous edge-to-edge mitral valve repair (PMVR) using the MitraClip system. BACKGROUND: Although gender-related differences have been extensively documented in patients who undergo surgery for moderate-to-severe (3+) and severe (4+) mitral regurgitation (MR), studies assessing whether these differences exist after PMVR are lacking. METHODS: Clinical and echocardiographic data through 12-month follow up from 171 consecutive patients whom underwent MitraClip implantation and were dichotomized by the gender (106 males and 65 females) were obtained. The primary safety endpoint was the incidence of major adverse events at 30 days and the primary efficacy endpoint was freedom from death, surgery for mitral valve dysfunction, or grade≥3+ MR at 12-month follow up. RESULTS: The primary safety endpoint was observed in four males (3.8%) and four females (6.2%) (P=0.358). Remarkable reduction in MR postprocedure was revealed in both groups, and these results were mostly sustained. Furthermore, left ventricle reverse remodeling and New York Heart Association (NYHA) functional class improvement were revealed in both groups, but females tended to demonstrate worse results over time (P=0.083). The primary efficacy endpoint obtained by Kaplan-Meier estimates was observed in 76.3 and 70.2%, respectively (log rank P=0.231). CONCLUSIONS: MitraClip implantation in patients with 3+ and 4+ MR is safe and efficacious until mid-term follow up, regardless of patients' gender. Despite improvement in NYHA functional class in both groups, female gender demonstrated a trend toward poorer results. Further validation of our findings is warranted.

On the accuracy of the segmentation process and transcatheter heart valve dimensions in TAVI patients.

Accurate segmentation of medical images is critical for generating patient-specific models suitable for computational analyses, particularly in the context of transcatheter aortic valve implantation (TAVI). This study aimed to quantify the accuracy of the segmentation process from medical images of TAVI patients to understand the uncertainty in patient-specific geometries. We also quantified discrepancies between actual and CT-related diameter measurements due to artifacts and intra-observer variability. Segmentation accuracy was assessed using both synthetic phantom models and patient-specific data. The impact of voxelization and CT scanner resolution on segmentation accuracy was evaluated, while the intersection over union (IoU) metric was used to compare the consistency of different segmentation methodologies. The voxelization process introduced a marginal error (<1%) in phantom models relative to CAD models. CT scanner resolution impacted segmented model accuracy only after a 7.5-fold increase in voxel size compared to the baseline medical image. IoU analysis revealed higher segmentation accuracy for calcification (93.4 ± 3.1 %) compared to the aortic wall (85.4 ± 8.4 %) and native valve leaflets (75.5 ± 6.3 %). Discrepancies in THV diameter measurements highlighted a ∼5 % error due to metallic artifacts, with variability among observers and at different THV heights. Errors due to voxel size, segmentation methodologies and CT-related artifacts can impact the reliability of patient-specific geometries and ultimately computational predictions used to asses clinical outcomes and enhance decision-making. This study underscores the importance of accurate segmentation and its standardization for patient-specific modeling of TAVI simulations.

Generation of a virtual cohort of TAVI patients for in silico trials: a statistical shape and machine learning analysis.

PURPOSE: In silico trials using computational modeling and simulations can complement clinical trials to improve the time-to-market of complex cardiovascular devices in humans. This study aims to investigate the significance of synthetic data in developing in silico trials for assessing the safety and efficacy of cardiovascular devices, focusing on bioprostheses designed for transcatheter aortic valve implantation (TAVI). METHODS: A statistical shape model (SSM) was employed to extract uncorrelated shape features from TAVI patients, enabling the augmentation of the original patient population into a clinically validated synthetic cohort. Machine learning techniques were utilized not only for risk stratification and classification but also for predicting the physiological variability within the original patient population. RESULTS: By randomly varying the statistical shape modes within a range of ± 2σ, a hundred virtual patients were generated, forming the synthetic cohort. Validation against the original patient population was conducted using morphological measurements. Support vector machine regression, based on selected shape modes (principal component scores), effectively predicted the peak pressure gradient across the stenosis (R-squared of 0.551 and RMSE of 11.67 mmHg). Multilayer perceptron neural network accurately predicted the optimal device size for implantation with high sensitivity and specificity (AUC = 0.98). CONCLUSION: The study highlights the potential of integrating computational predictions, advanced machine learning techniques, and synthetic data generation to improve predictive accuracy and assess TAVI-related outcomes through in silico trials.

On the Material Constitutive Behavior of the Aortic Root in Patients with Transcatheter Aortic Valve Implantation.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) is a minimally invasive procedure used to treat patients with severe aortic valve stenosis. However, there is limited knowledge on the material properties of the aortic root in TAVI patients, and this can impact the credibility of computer simulations. This study aimed to develop a non-invasive inverse approach for estimating reliable material constituents for the aortic root and calcified valve leaflets in patients undergoing TAVI. METHODS: The identification of material parameters is based on the simultaneous minimization of two cost functions, which define the difference between model predictions and cardiac-gated CT measurements of the aortic wall and valve orifice area. Validation of the inverse analysis output was performed comparing the numerical predictions with actual CT shapes and post-TAVI measures of implanted device diameter. RESULTS: A good agreement of the peak systolic shape of the aortic wall was found between simulations and imaging, with similarity index in the range in the range of 83.7% to 91.5% for n.20 patients. Not any statistical difference was observed between predictions and CT measures of orifice area for the stenotic aortic valve. After TAVI simulations, the measurements of SAPIEN 3 Ultra (S3) device diameter were in agreement with those from post-TAVI angio-CT imaging. A sensitivity analysis demonstrated a modest impact on the S3 diameters when altering the elastic material property of the aortic wall in the range of inverse analysis solution. CONCLUSIONS: Overall, this study demonstrates the feasibility and potential benefits of using non-invasive imaging techniques and computational modeling to estimate material properties in patients undergoing TAVI.

One-year clinical outcomes of transcatheter aortic valve implantation with the latest iteration of self-expanding or balloonexpandable devices: insights from the OPERA-TAVI registry.

BACKGROUND: Midterm comparative analyses of the latest iterations of the most used Evolut and SAPIEN platforms for transcatheter aortic valve implantation (TAVI) are lacking. AIMS: We aimed to compare 1-year clinical outcomes of TAVI patients receiving Evolut PRO/PRO+ (PRO) or SAPIEN 3 Ultra (ULTRA) devices in current real-world practice. METHODS: Among patients enrolled in the OPERA-TAVI registry, patients with complete 1-year follow-up were considered for the purpose of this analysis. One-to-one propensity score matching was used to compare TAVI patients receiving PRO or ULTRA devices. The primary endpoint was a composite of 1-year all-cause death, disabling stroke and rehospitalisation for heart failure. Five prespecified subgroups of patients were considered according to leaflet and left ventricular outflow tract calcifications, annulus dimensions and angulation, and leaflet morphology. RESULTS: Among a total of 1,897 patients, 587 matched pairs of patients with similar clinical and anatomical characteristics were compared. The primary composite endpoint did not differ between patients receiving PRO or ULTRA devices (Kaplan-Meier [KM] estimates 14.0% vs 11.9%; log-rank p=0.27). Patients receiving PRO devices had higher rates of 1-year disabling stroke (KM estimates 2.6% vs 0.4%; log-rank p=0.001), predominantly occurring within 30 days after TAVI (1.4% vs 0.0%; p=0.004). Outcomes were consistent across all the prespecified subsets of anatomical scenarios (all pinteraction>0.10). CONCLUSIONS: One-year clinical outcomes of patients undergoing transfemoral TAVI and receiving PRO or ULTRA devices in the current clinical practice were similar, but PRO patients had higher rates of disabling stroke. Outcomes did not differ across the different anatomical subsets of the aortic root.

Sex-Related Outcomes of Transcatheter Aortic Valve Implantation With Self-Expanding or Balloon-Expandable Valves: Insights from the OPERA-TAVI Registry.

Evidence regarding gender-related differences in response to transcatheter aortic valve implantation according to the valve type is lacking. This study aimed to evaluate the impact of gender on the treatment effect of Evolut PRO/PRO+ (PRO) or SAPIEN 3 Ultra (ULTRA) devices on clinical outcomes. The Comparative Analysis of Evolut PRO vs SAPIEN 3 Ultra Valves for Transfemoral Transcatheter Aortic Valve Implantation (OPERA-TAVI) is a multicenter, multinational registry including patients who underwent the latest-iteration PRO or ULTRA implantation. Overall, 1,174 of 1,897 patients were matched based on valve type and compared according to gender, whereas 470 men and 630 women were matched and compared according to valve type. The 30-day and 1-year outcomes were evaluated. In the PRO and ULTRA groups, men had a higher co-morbidity burden, whereas women had smaller aortic root. The 30-day (device success [DS], early safety outcome, permanent pacemaker implantation, patient-prosthesis mismatch, paravalvular regurgitation, bleedings, vascular complications, and all-cause death) and 1-year outcomes (all-cause death, stroke, and heart failure hospitalization) did not differ according to gender in both valve groups. However, the male gender decreased the likelihood of 30-day DS with ULTRA versus PRO (p for interaction = 0.047). A higher risk of 30-day permanent pacemaker implantation and 1-year stroke and a lower risk of patient-prosthesis mismatch was observed in PRO versus ULTRA, regardless of gender. In conclusion, gender did not modify the treatment effect of PRO versus ULTRA on clinical outcomes, except for 30-day DS, which was decreased in men (vs women) who received ULTRA (vs PRO).

Evolut PRO and SAPIEN ULTRA Performance in Small Aortic Annuli: The OPERA-TAVI Registry.

BACKGROUND: The performance of latest iteration transcatheter aortic valve replacement platforms in patients with small aortic anatomy remains underexplored. OBJECTIVES: The aim of this study was to evaluate effectiveness and performance between the self-expanding (SE) Evolut PRO and PRO+ and the balloon-expandable (BE) SAPIEN ULTRA in patients with small aortic annuli. METHODS: Data from the OPERA-TAVI (Comparative Analysis of Evolut PRO vs. SAPIEN 3 ULTRA Valves for Transfemoral Transcatheter Aortic Valve Implantation) registry were used, with 1:1 propensity score matching. Primary endpoints included 1-year effectiveness composite (all-cause mortality, disabling stroke, or heart failure hospitalization) and 30-day device-related (hemodynamic structural valve dysfunction and nonstructural valve dysfunction) outcomes. RESULTS: Among 3,516 patients, 251 matched pairs with aortic annular area <430 mm2 were assessed. The 1-year primary effectiveness outcome did not differ significantly between cohorts (SE 10.8% vs BE 11.2%; P = 0.91). The 30-day device-oriented composite outcome was more favorable in the Evolut PRO group (SE 4.8% vs BE 10.4%; P = 0.027). Notably, SE valve recipients showed higher rates of disabling stroke (SE 4.0% vs BE 0.0%; P < 0.01) and paravalvular leaks (mild or greater: SE 48.5% vs BE 18.6% [P < 0.001]; moderate: SE 4.5% vs BE 1.2% [P = 0.070]). The BE group had higher rates of prosthesis-patient mismatch (moderate or greater: SE 16.0% vs BE 47.1% [P < 0.001]; severe: SE 1.3% vs BE 5.7% [P = 0.197]) and more patients with residual mean gradients >20 mm Hg (SE 1.0% vs BE 13.5%; P < 0.001). CONCLUSIONS: In patients with small aortic annuli, transcatheter aortic valve replacement with latest iteration devices is safe. SE platforms are associated with more favorable device performance in terms of hemodynamic structural and nonstructural dysfunction. Randomized data are needed to validate these findings and guide informed device selection.

Parametric analysis of transcatheter aortic valve replacement in transcatheter aortic valve replacement: evaluation of coronary flow obstruction.

Transcatheter aortic valve replacement (TAVR) is increasingly being considered for use in younger patients having longer life expectancy than those who were initially treated. The TAVR-in-TAVR procedure represents an appealing strategy to treat failed transcatheter heart valves (THV) likely occurring in young patients. However, the permanent displacement of first THV can potentially compromise the coronary access and ultimately inhibit the blood flow circulation. The objective of this study was to use finite-element analysis (FEA) to quantify coronary flow in a patient who underwent TAVR-in-TAVR. A parametric investigation was carried out to determine the impact of both the implantation depth and device size on coronary flow for several deployment configurations. The FEAs consisted of first delivering the SAPIEN 3 Ultra THV and then positioning the Evolut PRO device. Findings indicates that high implantation depth and device undersize of the second THV could significantly reduce coronary flow to 20% of its estimated level before TAVR. Additionally, a positive correlation was observed between coronary flow and the valve-to-coronary distance (R = 0.86 and p = 0.032 for the left coronary artery, and R = 0.93 and p = 0.014 for the right coronary artery). This study demonstrated that computational modeling can provide valuable insights to improve the pre-procedural planning of TAVR-in-TAVR.

Biomechanical performance of the Bicaval Transcatheter System for the treatment of severe tricuspid regurgitation.

Introduction: Tricuspid regurgitation (TR) is a relatively common valvular disease, which can result from structural abnormalities of any anatomic part of the tricuspid valve. Severe TR is linked to congestive heart failure and hemodynamic impairment, resulting in high mortality when repaired by elective surgery. This study was undertaken to quantify the structural and hemodynamic performance of the novel Transcatheter Bicaval Valves System (TricValve) percutaneously implanted in the superior vena cava (SVC) and inferior vena cava (IVC) of two patients with severe TR and venous congestion. Methods: After developing the SVC and IVC device models, the contact pressure exerted on the vena cava wall was obtained by computational analysis. Both smoothed-particle hydrodynamics (SPH) and computational fluid dynamics were carried out to quantify caval reflux in the right atrium and the pressure field of pre- and post-TricValve scenarios, respectively. Results: Analysis of contact pressure highlighted the main anchoring area of the SVC device occurring near the SVC device belly, while the IVC device exerted pronounced forces in the device's proximal and distal parts. SPH-related flow velocities revealed the absence of caval reflux, and a decrease in time-averaged pressure was observed near the SVC and IVC after TricValve implantation. Discussion: Findings demonstrated the potential of computational tools for enhancing our understanding of the biomechanical performance of structural tricuspid valve interventions and improving the way we design next-generation transcatheter therapies to treat the tricuspid valve with heterotopic caval valve implantation.

A 3D adipogenesis platform to study the fate of fibro/adipogenic progenitors in muscular dystrophies.

In human dystrophies, progressive muscle wasting is exacerbated by ectopic deposition of fat and fibrous tissue originating from fibro/adipogenic progenitors (FAPs). In degenerating muscles, the ability of these cells to promote successful healing is attenuated, and FAPs aberrantly expand and differentiate into adipocytes and fibroblasts. Thus, arresting the fibro/adipogenic fate of FAPs, without affecting their physiological role, represents a valuable therapeutic strategy for patients affected by muscle diseases. Here, using a panel of adipose progenitor cells, including human-derived FAPs, coupled with pharmacological perturbations and proteome profiling, we report that LY2090314 interferes with a genuine adipogenic program acting as WNT surrogate for the stabilization of a competent ß-catenin transcriptional complex. To predict the beneficial impact of LY2090314 in limiting ectopic deposition of fat in human muscles, we combined a poly-ethylene-glycol-fibrinogen biomimetic matrix with these progenitor cells to create a miniaturized 3D model of adipogenesis. Using this scalable system, we demonstrated that a two-digit nanomolar dose of this compound effectively represses adipogenesis at higher 3D scale, thus indicating the potential for LY2090314 to limit FAP-derived fat infiltrates in dystrophic muscles.

Long-term longitudinal study on swine VML model.

BACKGROUND: Volumetric Muscle Loss (VML), resulting from severe trauma or surgical ablation, is a pathological condition preventing myofibers regeneration, since skeletal muscle owns the remarkable ability to restore tissue damage, but only when limited in size. The current surgical therapies employed in the treatment of this pathology, which particularly affects military personnel, do not yet provide satisfactory results. For this reason, more innovative approaches must be sought, specifically skeletal muscle tissue engineering seems to highlight promising results obtained from preclinical studies in VML mouse model. Despite the great results obtained in rodents, translation into human needs a comparable animal model in terms of size, in order to validate the efficacy of the tissue engineering approach reconstructing larger muscle mass (human-like). In this work we aim to demonstrate the validity of a porcine model, that has underwent a surgical ablation of a large muscle area, as a VML damage model. RESULTS: For this purpose, morphological, ultrasound, histological and fluorescence analyses were carried out on the scar tissue formed following the surgical ablation of the peroneus tertius muscle of Sus scrofa domesticus commonly called mini-pig. In particular, the replenishment of the damaged area, the macrophage infiltration and the vascularization at different time-points were evaluated up to the harvesting of the scar upon six months. CONCLUSION: Here we demonstrated that following VML damage, there is an extremely poor regenerative process in the swine muscle tissue, while the formation of fibrotic, scar tissue occurs. The analyses performed up to 180 days after the injury revealed the development of a stable, structured and cellularized tissue, provided with vessels and extracellular matrix acquiring the status of granulation tissue like in human.