Cynthia Laura Lefter

Background/Objectives: Vascular patches used in cardiovascular reconstruction remain limited by thrombosis, calcification, restricted remodeling, and inability to accommodate somatic growth. This proof-of-concept study aimed to fabricate and characterize porous vascular patches by fused deposition modeling (FDM) using polylactic acid (PLA) and thermoplastic polyurethane (TPU) in single-material and multilayer configurations. Methods: PLA/TPU patches with different polymer compositions, layer sequences, interfilament spacing, and staggered layer arrangements were fabricated by FDM. Mass and dimensional changes during in vitro immersion were assessed for the constituent polymers (n = 3 per polymer) and selected patch configurations (n = 1 per configuration). Patch microstructure and the in-plane dimensions of surface-visible pore openings were evaluated by top-view optical microscopy and ImageJ analysis, while time to first visually detectable fluid passage was assessed using a 22% (w/w) aqueous glycerol test solution under low hydrostatic pressure. Results: PLA and TPU exhibited distinct mass and dimensional profiles during 140 days of immersion, with mean mass increases of 1.37% and 3.68%, respectively. Selected patch specimens showed different temporal mass-change profiles during 42 days of immersion in phosphate-buffered saline (PBS). Descriptive pore measurements varied among the investigated configurations; V7b showed mean dimensions of 96.5 × 93.2 µm. In the exploratory test, fluid passage was first visually detected at 18 min (V5-TPU), 59 min (V6b) and 135 min (V7b). Conclusions: FDM enabled the fabrication of porous PLA/TPU vascular patch prototypes with different material composition and multilayer architectures. These findings establish a preliminary basis for further physicochemical, mechanical, biological, and hemodynamic evaluations of FDM-fabricated PLA/TPU vascular patches.

Infective Endocarditis (IE) incidence has increased in recent years, driven by emerging risk factors affecting both elderly and young adults. Also, the role of Non-Bacterial Thrombotic Endocarditis (NBTE) is gaining importance as it is a subtle, probably underdiagnosed entity. Moreover, the COVID-19 pandemic has influenced the epidemiology of endocarditis, raising questions about their relationship, diagnosis, and management. Diagnosis of IE is sometimes challenging, and classic criteria are now being rediscussed. The aim of our study is to provide a narrative review about how and why IE incidence is rising, the role of NBTE, the impact of the COVID-19 pandemic on endocarditis patterns, and the current diagnostic challenges we face in the post-pandemic era.

Background: Tissue-engineered pulmonary valves (TEPVs) hold considerable potential for improving outcomes in valve replacement surgeries. We investigated the surgical outcomes of TEPVs replacement in sheep, specifically examining the effects of valve type (decellularized versus adipose-derived stem cell-seeded valve [ADSC]) and the animal’s age at the surgery. The primary goals were to assess survival rates, postoperative complications, and the effects of cardiopulmonary bypass (CPB) on homeostasis. Methods: Nineteen juvenile and adult sheep were randomly assigned to orthotopic pulmonary valve replacement using either decellularized (DECELL, n = 10) or ADSC-seeded valves (CELL, n = 9). Blood gas analysis was conducted intraoperatively and postoperatively to assess CPB-related metabolic changes. The follow-up period after surgery was 6 months. Key demographic and operative parameters were recorded, and early and late postoperative complications were monitored. Results: No significant differences were observed in operative parameters or postoperative complications between the DECELL and CELL groups. Adult sheep exhibited longer anesthesia, CPB, and operative times due to tissue fragility but demonstrated better long-term survival than juveniles, who experienced more late-stage complications, including endocarditis. CPB exposure increased lactate and reduced hemoglobin levels, particularly in adult sheep, affecting homeostasis. The overall mortality rate was 42.1%, with deaths primarily attributed to congestive heart failure and endocarditis. Conclusion: Valve type did not significantly affect short-term outcomes and ADSC-seeding had no significant impact on operative parameters, postoperative complications, or survival rate. However, age remained a crucial factor influencing both surgical complexity and survival, highlighting the need for age-specific strategies in tissue-engineered valve applications.

Myocardial fibrosis (MF) is the excessive deposition of extracellular matrix (ECM) from myofibroblasts and is crucial in patients with heart failure (HF). Much work is still needed to fully understand its features and clinical role. This review aims to summarize the state-of-the-art of MF knowledge, focusing on assessment, quantification, predictive value, and future therapies. We performed a literature search about MF studies published between 2014 and 2024, including clinical studies on MF assessment or quantification, the role of MF as a prognostic factor in patients with HF, basic science studies on fibrosis assessment, and the role of the main mechanisms involved in MF. We identified 5161 potentially relevant articles. After excluding non-appropriate ones, we had 186 potentially suitable studies. After full reading and a review of references, 40 articles were included in our review: 8 were about MF assessment, 5 about quantification, and 27 about fibrosis as a prognostic factor. MF is a crucial process in patients with cardiac diseases and leads to HF and arrhythmias. Assessment and quantification have taken great steps forward, but more research is needed to strengthen MF’s role as a prognostic factor in the future. Basic science will play a key role in anti-fibrosis treatment.

Right ventricular (RV) failure is a common complication in multiple congenital heart disease (CHD), significantly increasing morbidity and mortality. Despite its impact, no therapies specifically target the failing RV. The growing population of CHD patients underscores the need to understand the pathophysiology of RV failure through preclinical research. This study aimed to develop an ovine model of RV failure induced by pressure and volume overload. A total of 14 juvenile sheep randomly underwent pulmonary artery banding (n = 6), pulmonary leaflet perforation (n = 4), and pulmonary annulotomy with transannular patching (TAP) (n = 4). Detailed anesthetic and surgical protocols were described, and intraoperative and early postoperative complications were evaluated. Acute RV pressure overload resulted in a 120% increase in RV pressure (p = 0.0312). The stroke volume index and cardiac index significantly declined (p = 0.0312), and there was a significant decrease in ScvO₂ (p = 0.0312). Both TAP and leaflet perforation achieved moderate-to-severe pulmonary regurgitation. Both procedures led to an incremental trend in RV pressures and resulted in a 24% increase in the stroke volume index. All techniques demonstrated safety and feasibility, with low mortality. This comprehensive model could be reproducible in other large animal models, offering a robust platform for preclinical research into CHD-RV failure models.