Recreating the inferior vena cava with a patient-specific biodegradable conduit

Abstract

Central MessageNovel tissue-engineered grafts may provide a simple and durable means of caval reconstruction in complex congenital heart disease.See Article page 924. Novel tissue-engineered grafts may provide a simple and durable means of caval reconstruction in complex congenital heart disease. See Article page 924. The Fontan operation with an extracardiac conduit for the total cavopulmonary connection requires creation of a bridge between the inferior vena cava and the pulmonary artery. Existing prosthetic grafts in this position are far from ideal, carrying the risks of thromboembolism, neointimal hyperplasia and obstruction, and the unsatisfying compromises involved in sizing a static conduit in a growing child. We continue to tolerate these prosthetic grafts for Fontan completion, however, because of their adaptability and ease of use, generally favorable hemodynamics, and lower risk of refractory atrial arrhythmias. In this issue, Fukunishi and colleagues1Fukunishi T. Best C.A. Sugiura T. Opfermann J. Ong C.S. Shinoka T. et al.Preclinical study of patient-specific cell-free nanofiber tissue-engineered vascular grafts using 3-dimensional printing in a sheep model.J Thorac Cardiovasc Surg. 2017; 153: 924-932PubMed Google Scholar describe a custom-fabricated biodegradable tube graft specifically designed for inferior vena cava interposition in Fontan-type operations, which has the potential to alleviate many of the risks associated with traditional grafts. This group's experience with similar devices actually dates back to 2001,2Naito Y. Imai Y. Shin'oka T. Kashiwagi J. Aoki M. Watanabe M. et al.Successful clinical application of a tissue-engineered graft for extracardiac Fontan.J Thorac Cardiovasc Surg. 2003; 125: 419-420Abstract Full Text Full Text PDF PubMed Scopus (66) Google Scholar when an obstructed hepatopulmonary conduit was replaced with an absorbable tubular scaffold seeded with autologous mononuclear cells. This human clinical work has continued for more than a decade, yielding a series of 25 children followed up for an average of 5.8 years, with encouraging patency rates, responsiveness to balloon dilation, and overall adequate clinical outcomes.3Hibino N. McGillicuddy E. Matumura G. Ichihara Y. Naito Y. Breuer C. et al.Late-term results of tissue-engineered vascular grafts in humans.J Thorac Cardiovasc Surg. 2010; 139: 431-436Abstract Full Text Full Text PDF PubMed Scopus (386) Google Scholar Although it builds on previous experience, the current ovine model of Fukunishi and colleagues1Fukunishi T. Best C.A. Sugiura T. Opfermann J. Ong C.S. Shinoka T. et al.Preclinical study of patient-specific cell-free nanofiber tissue-engineered vascular grafts using 3-dimensional printing in a sheep model.J Thorac Cardiovasc Surg. 2017; 153: 924-932PubMed Google Scholar marks a distinctly new stage in the evolution of tissue-engineered vascular grafts. First, this graft is custom spun according to patient-specific imaging data, which will allow careful fitting to complex anatomy and may even provide a platform by which computational fluid dynamics analysis may be used to optimize cavopulmonary flow patterns for a particular patient. Second, the graft is no longer seeded in advance with cellular material. Despite this seemingly fundamental change in preparation, Fukunishi and colleagues1Fukunishi T. Best C.A. Sugiura T. Opfermann J. Ong C.S. Shinoka T. et al.Preclinical study of patient-specific cell-free nanofiber tissue-engineered vascular grafts using 3-dimensional printing in a sheep model.J Thorac Cardiovasc Surg. 2017; 153: 924-932PubMed Google Scholar provide histologic evidence both of well-organized cellular replacement of the scaffold material and of acceptable strength and flow characteristics at 6-month follow-up, with no long-term requirement for anticoagulation. Safely eliminating the laboratory expertise, patient discomfort, storage limitations, and cost associated with stem cell isolation and seeding would allow what was once a niche product fabricated ad hoc at a research institution to become readily available at any hospital. In the pursuit of a patient-specific therapy for a complex condition, Fukunishi and colleagues1Fukunishi T. Best C.A. Sugiura T. Opfermann J. Ong C.S. Shinoka T. et al.Preclinical study of patient-specific cell-free nanofiber tissue-engineered vascular grafts using 3-dimensional printing in a sheep model.J Thorac Cardiovasc Surg. 2017; 153: 924-932PubMed Google Scholar have demonstrated a product that is more versatile and more biocompatible than anything currently available to our patients. Concerns regarding late stenosis, thrombus formation, and growth remain unanswered, and the potential for this material to function in other anatomic positions or in human patients has not been addressed. Even so, this sophisticated iteration of the tissue-engineered vascular graft may bring us closer to a device that better recapitulates the unassuming reliability of the normal, native vena cava. Preclinical study of patient-specific cell-free nanofiber tissue-engineered vascular grafts using 3-dimensional printing in a sheep modelThe Journal of Thoracic and Cardiovascular SurgeryVol. 153Issue 4PreviewTissue-engineered vascular grafts (TEVGs) offer potential to overcome limitations of current approaches for reconstruction in congenital heart disease by providing biodegradable scaffolds on which autologous cells proliferate and provide physiologic functionality. However, current TEVGs do not address the diverse anatomic requirements of individual patients. This study explores the feasibility of creating patient-specific TEVGs by combining 3-dimensional (3D) printing and electrospinning technology. Full-Text PDF Open Archive