Stentless porcine valves in the right ventricular outflow tract: improved durability?

European Journal of Cardio-thoracic Surgery 35 (2009) 600—605 www.elsevier.com/locate/ejcts Stentless porcine valves in the right ventricular outflow tract: improved durability?§ John A. Hawkins a,*, Christopher Todd Sower b, Linda M. Lambert a, Peter C. Kouretas a, Phillip T. Burch a, Aditya K. Kaza a, Michael D. Puchalski b, Angela T. Yetman b The Division of Cardiothoracic Surgery, Department of Surgery, Primary Children’s Medical Center and The University of Utah, Salt Lake City, UT, USA The Division of Pediatric Cardiology, Department of Pediatrics, Primary Children’s Medical Center and The University of Utah, Salt Lake City, UT, USA Received 1 September 2008; received in revised form 10 December 2008; accepted 15 December 2008; Available online 10 February 2009 Abstract Objective: Stentless porcine valves are commonly used for aortic valve replacement in adults, yet their long-term performance in the right ventricular (RV) outflow tract is unknown. We evaluated intermediate-term performance of stentless porcine valves in the RV outflow tract in 150 children and adults over a 10-year period. Methods: We retrospectively reviewed data on all patients undergoing placement of a pulmonary valve or RV-PA conduit with a stentless porcine prosthesis (19 mm) from 1998 to 2008. Valvar function was assessed with echocardiography. Freedom from reintervention (explantation or catheter-based intervention) was determined by actuarial methods. Results: A stentless porcine prosthesis was placed in the pulmonary position in 150 patients with a median weight and age of 50.1 kg (range 9.8—127) and 15.8 years (range 1.4—55), respectively. There were three early deaths (2%) and no late deaths. Actuarial freedom from reintervention was 100% at 1 year and 95.5% at 5 years. Peak transvalvar gradient at 1 and 5 years was 13  12 mmHg and 25  11 mmHg, respectively. At last follow-up no patient had severe insufficiency (PI), five patients had moderate PI and the remainder mild or no PI. Conclusions: Stentless porcine valves function well in the pulmonary position over the intermediate-term and are associated with low rates of reintervention in patients requiring a >19 mm valve or valved conduit. Longer-term follow-up and comparison with other alternatives will be necessary to determine if these valves are superior to commonly used allograft or bovine jugular venous valved conduits. # 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved. Keywords: Conduit; Pulmonary valve replacement; Stentless porcine valve 1. Introduction The implantation of a right ventricle to pulmonary conduit or insertion of a pulmonary valve is commonly used in the repair of a variety of congenital heart defects in both children and adults. Valve choices vary from cryopreserved allografts, bovine jugular venous valved conduits, and stented or stentless bioprostheses. Stentless porcine valves have been utilized extensively in the left ventricular outflow tract in adults [1], but information on durability in the right ventricular outflow tract has been limited, particularly in children [2—8]. Since 1998 we have utilized stentless porcine valves for many children and young adults needing either replacement of a conduit or placement of a pulmonary valve in the right ventricular outflow tract. This report evaluates the durability § Presented at the 22nd Annual Meeting of the European Association for Cardio-thoracic Surgery, Lisbon, Portugal, September 14—17, 2008. * Corresponding author. Address: Pediatric Cardiothoracic Surgery, Suite 2800, Primary Children’s Medical Center, 100 North Mario Capecchi Drive, Salt Lake City, UT 84108, USA. Tel.: +1 801 662 5566; fax: +1 801 662 5571. E-mail address: (J.A. Hawkins). and performance of these valves in the right ventricular outflow tract over the intermediate-term. 2. Patients and methods 2.1. Patients This study was approved by the institutional review board at the University of Utah. Data on all consecutive patients undergoing placement of a stentless porcine aortic bioprosthesis in the right ventricular outflow tract at the University of Utah Medical Center or Primary Children’s Medical Center between January 1998 and December 2007 were reviewed. During this time period, stentless porcine valves were utilized selectively along with cryopreserved allografts and stented bioprostheses. Selection of valve type was determined by surgeon preference and anatomic situation. In general, the stentless valve was chosen over the pulmonary allograft when valve insufficiency was the primary indication, since it was felt that the porcine valve remains competent longer than allografts. Pulmonary allografts were often 1010-7940/$ — see front matter # 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.ejcts.2008.12.028 a b J.A. Hawkins et al. / European Journal of Cardio-thoracic Surgery 35 (2009) 600—605 preferentially used during this period for situations that involved extensive pulmonary artery reconstruction. Approximately half of all valves 19 mm placed in the right ventricular outflow tract during this time period were stentless porcine bioprostheses, and form the basis for this study. Patient records were reviewed to determine patient demographics, diagnosis, indication for operation, other coexisting cardiac anomalies, size and manufacturer of the implanted valve, valve position (orthotopic vs extracardiac conduit), operative techniques, bypass and cross-clamp times. End points for evaluation of the valve or valved conduit included, reintervention (catheter-based or reoperation), late valve function determined by echocardiography, and death. All valves were sized according to calculated Z-scores and the patient’s weight and body surface area. In general, a Zscore between +1 and +3 was targeted and as large a valve as easily inserted was chosen. The smallest stentless porcine valve that is commercially available in the USA is a 19 mm. All 19 mm valves in this study were Medtronic Freestyle valves (Medtronic, Minneapolis, MN, USA). Valves sized 21 through 29 mm were Edwards Prima Plus valves (Edwards LifeSciences Corporation, Irvine, CA, USA). 4. Operative technique All procedures were accomplished with cardiopulmonary bypass with vacuum assisted venous drainage and mild hypothermia to approximately 34 8C. We do not routinely cross-clamp unless there is a need to do an additional procedure such as closure of an intracardiac defect or intracardiac valve procedure. We use ventricular fibrillation during the conduit or valve placement to avoid any possible air entry, in the case of an unrecognized intracardiac shunt or inadvertent entry into the left side of the heart or left atrium during the valve or conduit implantation. The valves are rigorously prepared according to the washing instructions of the manufacturer and left in saline until implantation. The (...truncated)