Journal of Artificial Organs最新文献

A 55-year-old woman developed Stanford type A acute aortic dissection complicated by occlusion of the left main coronary artery. The patient underwent an emergency ascending aortic replacement with concomitant coronary artery bypass grafting to the left anterior descending artery. Owing to extensive myocardial ischemia and the resultant severe cardiopulmonary impairment, the patient could not be weaned from the cardiopulmonary bypass. Therefore, central veno-arterial extracorporeal membrane oxygenation was initiated, with aortic perfusion via a branch of the ascending aortic graft and right atrial drainage. The central veno-arterial extracorporeal membrane oxygenation system was subsequently converted to a paracorporeal left ventricular assist device with an oxygenator, following which respiratory support was no longer required. The patient was listed for heart transplantation and underwent an elective conversion to a durable left ventricular assist device as a bridge-to-bridge strategy. During this operation, relocation of the outflow graft was necessary, and aortic valvuloplasty was performed simultaneously to address the mild residual post-dissection aortic insufficiency. Ultimately, the patient underwent heart transplantation more than 4 years after the bridge-to-bridge operation. An effective sequential mechanical circulatory support strategy, combined with meticulous technical management during bridge-to-bridge surgery, can successfully facilitate bridging to heart transplantation.

Aortic insufficiency (AI) that develops during long-term support with continuous-flow left ventricular assist devices (LVADs) remains a significant clinical problem. Abnormal flow patterns and altered wall shear stress (WSS) on the aortic valve are believed to contribute to leaflet remodeling, yet the hemodynamic influence of outflow graft orientation in patient-specific anatomies is not fully understood. This study investigated how different outflow graft angles affect aortic valve WSS and coronary perfusion using computational fluid dynamics (CFD). Three LVAD recipients who underwent preoperative ECG-gated coronary CT were retrospectively analyzed. Patient-specific geometries of the ascending aorta, aortic root, and coronary arteries were reconstructed. A cylindrical outflow graft was virtually anastomosed 25 mm above the sino-tubular junction, and three inclination angles (30°, 60°, 90°) were modeled with a fixed azimuthal angle of 90°. CFD simulations were performed under constant LVAD inflow (5.0 L/min) and uniform outlet pressure conditions. WSS on the aortic valve cusps and coronary flow rates were evaluated after achieving quasi-steady flow. Increasing outflow graft angle resulted in higher WSS on the ascending aortic wall opposite the anastomosis and consistently elevated WSS on the left coronary cusp. In some cases, the non-coronary cusp also showed localized WSS increases. Coronary flow decreased with shallower graft angles, with left coronary artery flow approximately halved at 30° compared with 90°, while right coronary flow exhibited a smaller reduction. Outflow graft angle substantially affects aortic valve WSS distribution and coronary perfusion. Steeper angles increase leaflet WSS, whereas shallower angles reduce coronary flow. Patient-specific CFD simulations may aid in optimizing graft positioning and reducing the risk of AI progression in LVAD patients.

Chronic kidney disease is a global health issue, and novel therapeutic alternatives to dialysis and kidney transplantation must be developed. Human-induced pluripotent stem cell-derived kidney organoids recapitulate developmental processes and mimic kidney-like structures in vitro and have thus attracted attention for treating chronic kidney disease. However, the limited vascularization and immaturity of human-induced pluripotent stem cell-derived kidney organoids remain major barriers to their clinical application. The latest technological advances and specific challenges in kidney organoid vascularization and maturation were thoroughly examined in this review. Diverse approaches were considered, including coculturing with endothelial cells, in vivo transplantation, applying biomaterials and microfluidic systems, controlling molecular signaling, and metabolic reprogramming. However, issues persist such as low reproducibility, lack of standardization, insufficient functional evaluations, and inadequate safety assessments. Future studies should focus on developing multifactorial and strategies for integrating multiple cell types, establishing maturation assessment criteria, and verifying the long-term functionality and safety of three-dimensional bioprinting technologies. Technologies for the vascularization and maturation of kidney organoids show promise as foundational methods for use innovative regenerative medicine and the development of drug discovery therapies.

Background: To evaluate the feasibility and safety of anticoagulation-free peripheral veno-arterial extracorporeal membrane oxygenation (VA-ECMO) during lung re-transplantation and to assess its impact on blood transfusion requirements and clinical outcomes.

Methods: In this single-center retrospective cohort (January 2023-April 2025), we included adults undergoing bilateral re-do lung transplantation on peripheral VA-ECMO with an anticoagulation-avoidance protocol; primary lung transplants were not included. Data on patient demographics, intraoperative transfusion volumes, postoperative complications, and survival were collected. The primary outcomes were intraoperative packed red blood cell transfusion volume and overall survival; secondary outcomes included incidence of primary graft dysfunction, acute kidney injury, and hemorrhagic and thromboembolic events. Continuous variables are reported as medians with interquartile ranges, and survival was estimated using the Kaplan-Meier method.

Results: Seven patients (median age, 42 years; range, 30-56 years) underwent re-transplantation for chronic lung allograft dysfunction. The median intraoperative transfusion requirement was 560 ml (interquartile range 280-1050 ml). One patient developed primary graft dysfunction of grade 3and two developed stage 3 acute kidney injury requiring renal replacement therapy. Two developed deep venous thrombosis nonrelated to ECMO cannulation; no pulmonary embolism occurred. At a median follow-up of 469 days, all patients survived without evidence of recurrence of chronic lung allograft dysfunction.

Conclusions: Full anticoagulation-free peripheral VA-ECMO during lung re-transplantation is feasible and safe, with acceptable complication rates and potential reduction in transfusion requirements. Larger, multicenter studies are warranted to confirm these findings.