You are in: eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Cardiothoracic Surgery Aortic Valve Disease and the Ross OperationArticle Last Updated: Oct 17, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 9
  Author: Bahaaldin Alsoufi, MD, Consulting Staff, Department of Pediatric Surgery, King Faisal Heart Institute, King Faisal Specialist Hospital and Research Centre Bahaaldin Alsoufi is a member of the following medical societies: American College of Surgeons, Royal College of Physicians and Surgeons of Canada, and Society of Thoracic Surgeons Coauthor(s): Christopher A Caldarone, MD, Associate Professor, Department of Surgery, The Hospital for Sick Children, University of Toronto; Gregory B Dalshaug, MD, Assistant Professor, Division of Cardiovascular Surgery, Royal University Hospital Editors: Daniel S Schwartz, MD, FACS, Clinical Assistant Professor of Cardiothoracic Surgery, New York University School of Medicine; Consulting Staff, Department of Surgery, Division of Thoracic Surgery, North Shore University Hospital/Long Island Jewish Medical Center; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; John Myers, MD, Director, Pediatric and Congenital Cardiovascular Surgery, Departments of Surgery and Pediatrics, Professor, Penn State Children's Hospital, Milton S Hershey Medical Center; Daniel Rauch, MD, FAAP, Director, Pediatric Hospitalist Program, Associate Professor, Department of Pediatrics, New York University School of Medicine; John Kupferschmid, MD, Director of Congenital Heart Surgery, Department of Surgery, Methodist Children's Hospital at San Antonio Author and Editor Disclosure Synonyms and related keywords: aortic valve disease, AVR, aortic valve replacement, aortic-valve replacement, aortic valve repair, aortic valve disease in children, Ross operation, Ross procedure, Ross-Konno procedure INTRODUCTIONSection 2 of 9
  Aortic valve replacement (AVR) is occasionally required in infants and children. Common indications for AVR in children include management of the following:
Although the ideal aortic valve substitute does not exist, desirable characteristics include the following:
Mechanical valve prostheses are not ideal valve substitutes in children. Although the incidence of structural valve deterioration is negligible, these prostheses have substantial limitations at the time of implantation because of the lack of appropriately sized prostheses for small children and neonates. In addition, the absence of the potential for growth can result in patient-prosthesis size mismatch as the child grows, and repeat replacement may be needed. Moreover, mechanical valves require lifetime anticoagulation with its associated activity limitations, difficulties with future pregnancy, and lifetime risk of thromboembolic and bleeding complications. Homografts and bioprosthetic valves are also problematic in children. Although these biologic valves do not require anticoagulation, they also do not allow for growth. Also, their durability is limited in the pediatric population because of the high risk of accelerated structural valve degeneration and early calcification. In addition, limited availability of appropriately sized homografts and bioprostheses can be a problem. Several techniques for aortic valve repair have been applied in children, including pericardial leaflet extension, commissural reconstruction, annuloplasty, reduction of the sinus of Valsalva, remodeling of the sinotubular junction, and even complete leaflet replacement by using autologous pericardium. Aortic valve repair in the child allows for continuing growth and eliminates the need for anticoagulation. However, long-term results so far have been less than satisfactory, and residual lesions, such as regurgitation or stenosis, are common. Despite evidence of stabilized ventricular dimensions and improved functional classification in children after aortic valve repair, residual lesions continue to progress. The regurgitant fraction and/or peak gradients across the LVOT increase, and patients eventually require repeat operation and possible valve replacement. The role of valve repair in children as a cure or a temporizing measure remains incompletely defined. Nevertheless, aortic valve repair delays ultimate replacement until alternative options for valve replacement can be offered to patients after somatic growth is complete, pregnancy occurs, or compliance with anticoagulation regimens improve. The Ross procedure with a pulmonary autograft provides excellent hemodynamic flow characteristics, it is amenable to growth, and patients do not require anticoagulation. Despite several shortcomings of the Ross procedure (discussed later in this article), it has emerged as a popular choice for managing AVR in infants and children. History of the ProcedureThe procedure of replacing the aortic valve with the patient's own pulmonary valve and then using a pulmonary allograft to replace the pulmonary valve is commonly referred to as the Ross procedure. Lower, Stofer, and Shumway investigated the concept in 1960 using autotransplantation of the pulmonic valve into the descending thoracic aorta of dogs. Pillsbury and Shumway described autotransplantation into the aortic annulus in 1966. However, the first clinical application occurred 1 year later, as reported by Donald Ross in 1967 (see Image 1). Since then, the operation has steadily gained acceptance, and the indications for the procedure have expanded. RELEVANT ANATOMYSection 3 of 9
Thorough knowledge of cardiac anatomy is required to perform the Ross procedure. In particular, an understanding the left coronary artery, the first septal branch of the left anterior descending artery, and their relationship to the aortic root and the right ventricular outflow tract is important (see Image 2). During harvest of the pulmonary autograft, an appreciation of the subpulmonary conal musculature (ie, the thin muscular tube beneath the pulmonary valve) facilitates the dissection. Knowledge of the configuration of the LVOT and the relationship to the conduction system is important when enlargement of the LVOT is required (Ross-Konno procedure). CONTRAINDICATIONSSection 4 of 9
The Ross operation is a technically demanding procedure, and the surgeon's experience with this operation and similar procedures affects the decision-making process. Patient factors that affect this process include the patient's age, lifestyle, and coexisting cardiac and noncardiac disease. Contraindications include the following:
TREATMENTSection 5 of 9
Preoperative detailsEchocardiography is used preoperatively to assess the aortic valve pathology, levels of LVOT obstruction and associated cardiac abnormalities. The pulmonary valve is assessed for clinically significant regurgitation or any other pathology. Echocardiography is also useful for assessing the sizes of the aorta and pulmonary annulus. A disparity in size of >2-3 mm is likely to require augmentation or reduction in the diameter of the aortic annulus. Intraoperative detailsAll procedures are performed though a midline sternotomy. Cardiopulmonary bypass is established by means of standard aortic and bicaval venous cannulation. The left ventricle is decompressed by venting it through the right superior pulmonary vein. Mild hypothermia (32-34°) is used with a combination of antegrade and retrograde cold-blood cardioplegia. Antegrade cardioplegia is initially administered through the root and then by directly cannulating the coronary artery at 20-minute intervals. The aorta is transected 1.5 cm above the right coronary artery. The aortic valve is inspected and repaired if possible. If the valve is not repairable, the leaflets are completely excised, and calcium is débrided if present. The main pulmonary artery is partially opened just proximal to the bifurcation, and the valve is inspected to ensure normal anatomy and function. Once the decision is made to proceed with the Ross procedure, the coronary buttons are prepared. A generous rim of aorta is left around each ostium to allow for suturing to the pulmonary autograft later. The pulmonary artery is separated from the aorta up to the bifurcation and completely divided (see Image 3). The autograft is harvested by placing a right-angled clamp through the valve and by bringing the tip through the infundibulum approximately 1 cm below the base of the cusps (see Image 4). The right ventricular outflow tract is then opened circumferentially by using scissors. At the anterior aspect, care must be taken to avoid the conus branch of the right coronary artery. When the dissection proceeds laterally, the left anterior descending artery and its first septal branch are at risk if meticulous dissection is not performed (see Image 2). After the autograft is harvested, retrograde cardioplegia is administered, and the small venous branches are ligated in the bed of the harvested autograft. The autograft and the right ventricular outflow tract are then sized with standard sizers to select an appropriately sized pulmonary homograft to be prepared. The aortic root annulus is also sized to determine if any discrepancy must be addressed. An annular size difference of 2-3 mm is well tolerated. If the aortic annulus is too large, reduction is best achieved with an imbricating suture passed circumferentially at the level of the annulus and tied over a dilator the size of the pulmonary autograft. As an alternative, a series of mattress sutures can be used with care to avoid the region of the conduction system. If the aortic root annulus is too small, aortoventriculoplasty combined with the Ross procedure (commonly known as the Ross-Konno procedure) is appropriate (see Images 8-9). The autograft is sutured to the aortic valve annulus by using interrupted 4-0 polypropylene. If no further growth is required, the sutures are tied around a circumferential strip of polytetrafluoroethylene (Teflon; DuPont, Wilmington, DE) felt approximately 3 mm wide (see Image 5). The graft should be orientated so that the commissures of the autograft line up with the commissures of the excised aortic valve. Marking sutures on the adventitia side to identify the middle of the cusps aids in reattaching the coronary arteries. A small opening is made in the left coronary sinus of the autograft, and the left coronary artery is anastomosed by using a running 6-0 polypropylene. The distal aortic anastomosis is then constructed with a continuous 4-0 polypropylene. The aortic root is de-aired and insufflated to test the suture lines and to allow for proper placement of the right coronary artery after the autograft is distended. The anastomosis is constructed in a fashion similar to that used for the left coronary button. Antegrade cardioplegia can now be administered, and bleeding in the bed of the harvested autograft site can be addressed. A cryopreserved pulmonary homograft is then trimmed appropriately, and the distal anastomosis is performed by using a continuous 4-0 polypropylene suture. The proximal anastomosis is constructed with continuous 5-0 polypropylene by taking care to avoid injury to the underlying first septal branch from the left anterior descending artery (see Image 6). The patient is then placed in steep Trendelenburg position. While the aortic and left ventricular vents are aspirated, the cross-clamp can be removed. The rest of the anterior portion of the homograft anastomosis can be completed with the heart beating. The patient is weaned from cardiopulmonary bypass. Protamine is administered, and patient is decannulated. Transesophageal echocardiography is used to assess the function of the autograft and the homograft after the procedure is completed (see Image 7). The autograft implantation technique described is the mini-root reimplantation technique. It is the preferred implantation strategy that the present authors use at our institution. Other implantation techniques are similar to those described for homografts. Examples include the subcoronary and cylinder-inclusion techniques that some surgeons prefer. In the Ross registry database, 81% of autografts were implanted by using the root technique; the subcoronary was used in 11%, and the inclusion technique was used in 6%. Postoperative detailsStandard postoperative cardiac management is administered. Patients can generally be weaned from ventilatory support in the early postoperative period, the exception being a neonate who was critically ill before surgery. Follow-upPatients are examined 4 weeks postoperatively to address any surgical issues. They should also continue to undergo biannual echocardiography to assess function of the right- and left-sided semilunar valves. After undergoing surgical repair of aortic valve disease, patients are given antibiotics to prevent endocarditis before they receive any procedures that may cause bacteremia. For more information, see Antibiotic Prophylactic Regimens for Endocarditis. OUTCOME AND PROGNOSISSection 6 of 9
Surgical resultsThe Ross procedure is a safe operation and can be performed with a low mortality risk. Data from The International Registry for the Ross Procedure, which includes 6088 patients, reveals an early mortality rate of 3.3%. Perioperative complications are uncommon and include arrhythmias in 3% of patients, bleeding in 2%, stroke in 1%, and sepsis in 1%. Many groups have reported results even more favorable than these in children and young adults undergoing the Ross procedure. Surgical mortality rates approach 0% in different series from experienced centers despite the complexity of the procedure. Actuarial long-term survival for patients undergoing the Ross procedure in the Ross registry and in several surgical series is 80-90% at 10 years and 70-80% at 20 years. These favorable results reflect selection bias because patients undergoing the Ross procedure are usually young with minimal comorbidities such as coronary artery disease. Durability and autograft failure Early autograft failure or dysfunction requiring replacement of the autograft at the time of surgical insertion or at the time of reoperation within 6 months of the original Ross procedure is rare when the surgeons are experienced. The incidence is less than 1% in the Ross registry. This failure or dysfunction is usually due to technical problems, such as leaflet distortion and leaflet injury during harvest or implantation of the autograft. Pulmonary autograft is a durable replacement for the aortic valve. Initial data that Dr Ross collected demonstrated a rate of autograft failure and replacement of 2.5% per patient year and an actuarial event-free rate of 48% at 19 years. Several advances in technique, including the root-replacement technique and procedures to limit potential autograft dilation, have improved outcomes after the Ross procedure. In the most recent analysis of data from Ross registry, rates of freedom from explantation of failing autografts was 89% and 82% at 10 and 25 years, respectively. Valve durability is clearly superior to that of homografts or bioprosthetic valves, as the last 2 undergo calcific degeneration and require replacement, especially in young patients in whom expected survival is long and in whom early degeneration of biologic valve substitutes is accelerated. Moreover, valve-related complications (eg, endocarditis, valve pannus, thrombosis) are low following the Ross procedure. Consequently, the need for valve explantation secondary to the aforementioned problems is rare compared with mechanical valves. An increasing concern is dilatation of the neoaortic root after the Ross procedure that leads to progressive aortic regurgitation, especially in the setting of a geometric mismatch of aortic and pulmonary roots and bicuspid regurgitant aortic valve. Several groups have identified specific subsets of patients at high risk of autograft dilatation and recurrent regurgitation. Dilatation of the sinuses of Valsalva results in root aneurysm, even without clinically significant aortic regurgitation, whereas dilatation of the sinotubular junction causes recurrent regurgitation, especially in patients who undergo root implantation of the autograft. Dilatation of the sinotubular junction is probably the most common cause of pulmonary autograft failure. Although valve replacement may be required, several groups have reported that valve-sparing replacement of the aortic root and ascending aorta eliminates the aneurysmal dilated wall and restores valve competency. Several investigators reported improved performance of the autograft in younger children compared with older children and adults, with reduced rates of autograft dilatation and repeat operations. Their findings suggest that autografts in young children can best adapt to systemic pressures. Nonetheless, many surgeons are reconsidering the Ross procedure, especially for the treatment of congenital and bicuspid aortic valve disease. Finally, several groups have reported modifications of the valve implantation techniques, such as adjusting the diameter of the aortic annulus and/or the sinotubular junction of the aorta by using polytetrafluoroethylene (Teflon; DuPont) strips, implanting the autografts into a polyethylene terephthalate (Dacron; DuPont) graft or wrapping the autograft with glutarylaldehyde-treated pericardium to prevent dilatation of the autograft. Further follow-up is needed to assess the utility of these modifications. Pulmonary homograft degeneration The pulmonary homograft used to reconstruct the right ventricular outflow tract is subject to calcific degeneration, which, in addition to its failure to grow with the child, will likely lead to repeat operation and conduit replacement. It is generally acknowledged that the pulmonary homograft placed during the Ross procedure has greater longevity than that used for reconstruction of the right ventricular outflow tract for repair of congenital heart disease. The reason is presumably its orthotopic position, normal pulmonary arteries, and pulmonary vascular resistance. However, recent data indicate that replacement is still necessary. Factors associated with homograft dysfunction include use of an aortic homograft, a small homograft, a recipient younger than 10 years, homograft storage time, and immune-mediated reactions. The reported incidence of homograft dysfunction is 6-20% at 10 years after the Ross procedure. In the Ross registry, rates of freedom from pulmonary homograft replacement were 91% and 84% at 10 and 25 years, respectively. When re-replacement of the subpulmonary homograft is required, the surgical results are associated with minimal mortality. This observation further supports the utility of the Ross procedure for valve replacement in children and young adults. LifestylePatients undergoing the Ross procedure do not require anticoagulation. Patients have minimal restrictions on their lifestyle and do not require cardiac medications to maintain or preserve valve function. Despite the development of mildly elevated gradients across the pulmonary homograft, patients treated with Ross surgery have near-normal exercise endurance, and most have a New York Heart Association (NYHA) class of I. A recent echocardiographic comparison of rest and exercise hemodynamics showed that hemodynamic characteristics and exercise performance in athletes after Ross procedure were similar to those of age-matched healthy athletes. FUTURE AND CONTROVERSIESSection 7 of 9
Although the Ross procedure for AVR in the pediatric population is more demanding than straightforward valve replacement, it offers distinct advantages, including excellent hemodynamic flow characteristics, potential for growth, excellent patient survival, and minimal incidence of late embolic complications. Repeat operations on the reconstructed right ventricular outflow tract are infrequent and associated with low surgical risk. Surveillance for autograft dilatation is necessary, as it may result in aneurysm formation and/or recurrent aortic regurgitation. Reoperation on the autograft may be required; however, valve-sparing root replacement can be performed to preserve the autograft valve. The advantages of the Ross procedure, despite its limitations, make it the currently preferred choice for AVR in children. Advances in the techniques of aortic valve repair and developments in valve-substitute technology may offer improved alternatives for children with aortic valve disease in the future. MULTIMEDIASection 8 of 9
REFERENCESSection 9 of 9
Aortic Valve Disease and the Ross Operation excerpt Article Last Updated: Oct 17, 2006 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
