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The Ross/Konno Procedure

  • Peter Pastuszko
    Affiliations
    From the Division of Cardiothoracic Surgery, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
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  • Thomas L. Spray
    Correspondence
    Address reprint requests to Thomas L. Spray, MD, Division of Cardiothoracic Surgery, The Children's Hospital of Philadelphia, 31th Street and Civic Center Boulevard, Suite 8527, Philadelphia, PA 19104
    Affiliations
    From the Division of Cardiothoracic Surgery, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
    Search for articles by this author
      Left ventricular outflow tract obstruction in neonates and infants encompasses a variety of anatomical defects, ranging from isolated aortic valve stenosis or discrete subaortic stenosis to the more complex tunnel subaortic stenosis that is often associated with hypoplasia of the aortic valve. Whereas balloon dilatation for congenital aortic valve stenosis and membrane enucleation for discrete subaortic lesions are well-established approaches for discrete valvar or subvalvar obstruction, more diffuse disease involving several levels of left ventricular outflow tract (LVOT) obstruction presents a therapeutic challenge.
      The ideal treatment of complex LVOT obstruction compounded by critical aortic stenosis or severe valve dysplasia has yet to be identified. When the left ventricle is not sufficiently developed to support the systemic circulation or when multiple levels of LVOT obstruction coexist with mitral valve stenosis and left ventricular hypoplasia conversion to a single-ventricle physiology may be the pathway of choice. In the group of patients who are candidates for a two-ventricle repair, alternatives include root-enlarging procedures combined with placement of valve prosthesis or allograft, left ventricle to aorta valved conduit placement and pulmonary autograft root replacement with aortoventriculoplasty (Ross-Konno procedure). Mechanical valves, with their size limitations as well as lifetime anticoagulation requirement, play only a minor role in the treatment of a neonate. Aortic allografts have been proven to be of limited durability in the younger patient population. It is in this population of infants, where a two-ventricle repair remains a viable option, that a Ross-Konno operation may provide the best chance for a complete relief of obstruction and reasonable long-term durability.
      First described in 1967, the Ross procedure utilized the pulmonary autograft for the replacement of a diseased aortic valve and an allograft to replace the transplanted pulmonary valve.
      • Ross D
      Replacement of aortic and mitral valves with a pulmonary autograft.
      It has become an attractive option for young individuals with aortic root pathology not amenable to repair, with well-documented excellent long-term results.
      • Matsuki O
      • Okita Y
      • Almeida RS
      • et al.
      Two decades' experience with aortic valve replacement with pulmonary autograft.
      • Ross D
      The pulmonary autograft: History and basic techniques.
      • Elkins RC
      Both experimental as well as clinical data have shown that the pulmonary autograft can tolerate the aortic diastolic pressures and function well in the aortic position. It is free of the high early failure rates observed with aortic homografts and avoids the problems of sizing and anticoagulation seen with mechanical valves,
      • Gerosa G
      • McKey R
      • et al.
      Comparison of the aortic homograft and the pulmonary autograft for aortic valve or root replacement in children.
      although late dilation and valve failures do occur in a small percentage of patients. Finally, it has been shown to have potential for growth in the LVOT position, making it ideal for even the youngest individuals.
      • Gerosa G
      • McKey R
      • Ross DN
      Replacement of the aortic valve or root with a pulmonary autograft in children.
      • Elkins RC
      • Knott-Craig CJ
      • Ward K
      • et al.
      Pulmonary autograft in children: Realized growth potential.
      The Ross procedure, however, in its initial form was applied only to those “suitable” cases with nearly perfect size match between the aortic and pulmonary valves. It was not until the pulmonary autograft was combined with the Konno aortoventriculoplasty
      • Konno S
      • Imai Y
      • Iida Y
      • et al.
      A new method for prosthetic valve replacement in congenital aortic stenosis associated with hypoplasia of the aortic valve ring.
      that it became such an attractive option for young patients with diffuse LVOT stenosis associated with significant aortic valve stenosis or dysplasia.
      The Ross-Konno procedure is not without disadvantages. The ventriculoplasty carries a risk of heart block, while the mobilization and reimplantation of the coronary arteries is associated with some morbidity and residual ventricular septal defects are occasionally seen. In addition, the procedure converts a single-valve to a double-valve operation making it a more technically challenging undertaking.

      Anatomical Considerations

      The significant improvement in the mortality and morbidity associated with the Ross procedure from it's inception to the present reflects not just the learning curve but also a more thorough understanding of the involved anatomy. Ross, in his initial experience with the procedure, noted a very high incidence of rhythm abnormalities as well as electrocardiogram findings consistent with myocardial ischemia. He noted that those abnormalities were not seen in those patients who underwent homograft replacement of the aortic valve. After a detailed analysis of the anatomy of the pulmonary artery root, he concluded that the first portion of the left coronary system is in close proximity to the posterior surface of the pulmonary artery. In particular, the first septal perforator, the source of blood supply to the right bundle branch, is located close to the pulmonary valve, hence it is susceptible to injury.
      • Geens M
      • Gonzalez-Lavin L
      • Dawbarn C
      • Ross DN
      The surgical anatomy of the pulmonary artery root in relation to the pulmonary valve autograft and surgery of the right ventricular outflow tract.
      This discovery led to the modification of the original technique with subsequent “enucleation” of the pulmonary valve along the posterior wall to avoid injury to these vessels. Postoperative rhythm disturbances are still common, however, possibly related to the severe left ventricular hypertrophy seen in most of the candidates for the procedure (CHOP data).
      Anatomic considerations apply to the Konno procedure as well.
      • Sud A
      • Parker F
      • Magilligan DJ
      Anatomy of the aortic root.
      To avoid injury to the conduction system, the location of the ventricular septal incision must be to the left of the right coronary ostium. Once the annulus is divided, the septal incision is extended in an oblique and nearly transverse direction to the left of the conal papillary muscle of the tricuspid valve.

      Surgical Technique

      Over the years, several different pulmonary autograft implantation methods have been developed.
      • Ross D
      Replacement of the aortic valve with a pulmonary autograft: The “switch operation”.
      The one most commonly used, and the one we utilize in the Ross-Konno procedure, is the technique of root replacement of the ascending aorta with the autograft pulmonary artery conduit.
      • Spray TL
      Technique of pulmonary autograft aortic valve replacement in children (the Ross procedure).
      Other methods proposed, such as free-hand subcoronary implantation and inclusion root replacement, have fallen out favor either a result of technical difficulties or size discrepancy between the aortic valve annulus and the autograft annulus. The root replacement technique, when combined with an annulus enlarging procedure, can be used with good results even with the significant size difference between the autograft and the original aortic annulus in patients with complex LVOTO.
      The level of hypothermia utilized for the procedure is determined by the presence of associated defects. Complex left ventricular outflow tract obstruction is frequently associated with some form of arch defect. Most often the arch anomaly, such as an interrupted aortic arch or aortic coarctation, has previously been addressed and does not require concurrent repair or revision. If, however, arch repair is necessary, a brief period of circulatory arrest is often utilized. Otherwise, the procedure is performed under moderate systemic hypothermia (28°C).
      Figure thumbnail fx1
      1After a standard median sternotomy is performed, the aorta is cannulated distally, close to the origin of the innominate artery. This facilitates the exposure and subsequent dissection. The superior and inferior vena cavae are cannulated separately. The aorta and the pulmonary artery are extensively mobilized, and the adventitial plane between the two vessels is dissected proximally, close to the origin of the right coronary artery. The aortic arch is examined for any abnormalities and landmarks are identified for subsequent incisions. Cardiopulmonary bypass is initiated and the patient is cooled. A left ventricular vent is placed through the right superior pulmonary vein.
      Figure thumbnail fx2
      2The aorta is cross-clamped and cardiopegia administered antegrade into the root if there is no significant aortic regurgitation (AR) and directly into the coronary ostia or retrograde if there is predominant AR. After the heart is arrested, the main pulmonary artery is divided anteriorly and obliquely to the left at the level of the bifurcation. The pulmonary valve is then inspected for any defects.
      Figure thumbnail fx3
      3If the pulmonary valve appears normal, the pulmonary artery is completely transected, and the surrounding adventitial tissue is mobilized using cautery and sharp dissection proximally, down to the level of the right ventricular muscle. The excision of the pulmonary autograft from the right ventricular outflow tract is then completed.
      Figure thumbnail fx4
      4The right ventricular wall is incised first anteriorly, with the position of this incision carefully chosen to be below the sinuses of the pulmonary valve.
      Figure thumbnail fx5
      5The incision is carried medially and laterally towards the ventricular septum and an infundibular muscle flap is created based on the expected depth of the ventriculoplasty that will be filled in by RV freewall muscle, the pulmonary valve is “enucleated” from the right ventricular outflow tract posteriorly. This maneuver prevents injury to the left anterior descending artery and the first septal perforator branch. We prefer to use cautery to remove posterior attachments of the pulmonary valve. This coagulates small vessels found in the area and prevents bleeding that may be difficult to control at a later time. If the plan is to repair the aortoventriculoplasty with a prosthetic patch, the extent of the infundibular muscle flap may be minimized. Once the pulmonary autograft is removed, the right ventricular muscle rim, with exception of the infundibular flap, is trimmed to within 3 to 4 mm of the valve and thinned to prevent subaortic narrowing once it is sewn into the LVOT. Infants with complex LVOTO often have significant pulmonary hypertension and PV hypertrophy, making debridement of the thick RV muscle necessary.
      Figure thumbnail fx6
      6After the autograft preparation is completed, attention is directed to the aorta and the aortic valve. The aorta is divided distally above the commissural attachments. If an arch defect, such as a coarctation or an interrupted aortic arch, is present, it is repaired often with a combination of primary anastomosis and homograft patch augmentation to create a good size match between the autograft and the distal aorta. Discrepancy at the initial suture line can cause dilation of the sinotubular junction if too large and stenosis with accelerated autograft valve failure if too small. Aortic buttons containing the coronary artery ostia are then excised and mobilized. The proximal aortic wall is removed down to 3 to 4 mm from the base of the coronary sinuses.
      Figure thumbnail fx7
      7The next step of the procedure is determined by the size discrepancy between the pulmonary autograft and the aortic annulus. If the size difference is only minor, aortic valve removal alone or an incision across the annulus such as the one used for Nicks valvuloplasty, may open the root sufficiently.
      Figure thumbnail fx8
      8If the aortic annulus requires more significant enlargement, the Ross-Konno procedure is performed. The septum is inspected, and the extent of the subaortic stenosis is determined. The aortic annulus and the ventricular septum are incised 4 to 5 mm to the left of the right coronary ostia or between the commissural attachments of the left and right coronary leaflets. This incision extends in an oblique and almost transverse direction, to the left of the conal papillary muscle of the tricuspid valve, thus avoiding an injury to the conduction tissue. The incision into the septum is carried down to just below the level of the subaortic stenosis. Any associated abnormal tissue, such as endocardial fibroelastosis or hypertrophied muscle is resected at this point.
      Figure thumbnail fx9
      9The pulmonary autograft is then sized to the left ventricular outflow tract.
      Figure thumbnail fx10
      10If the aortic annulus requires significant enlargement or the septal incision is too long to use the infundibular muscle flap, the septal defect is repaired with a v-shaped prosthetic patch. The autograft is then anastomosed to the aortic annulus posteriorly and to the superior edge of the patch. If the septal defect is small, it can often be then repaired with the infundibular muscle flap. In infants with an associated conoventricular VSD, use of the infundibular muscle flap is avoided, because the thickness and the need to suture to the TV annulus can cause inflow obstruction to the PV.
      Figure thumbnail fx11
      11The pulmonary autograft is anastomosed to the LVOT with a running absorbable suture, positioning the autograft so that the posterior sinus of the pulmonary autograft becomes the left coronary sinus and the infundibular muscle fits into the ventriculoplasty. After the first suture line is completed, the proximal aortic wall remnant is oversewn over this anastomosis with another running suture to aid hemostasis. In addition, this maneuver may potentially prevent late annular dilatation.
      Figure thumbnail fx12
      12The positions of the coronary arteries are determined, and, after suitable openings are excised in the pulmonary artery, the coronary ostia are anastomosed to the pulmonary artery with fine monofilament suture.
      Figure thumbnail fx13
      13Finally, after being trimmed to appropriate length, the distal pulmonary artery of the autograft is sutured to the aorta. Reinforcement of the distal suture line with a strip of prosthetic material is sometimes used in older patients to prevent dilation of the sino-tubular junction.
      Figure thumbnail fx14
      14The final segment of the procedure involves the right ventricular outflow tract reconstruction, more commonly using a pulmonary allograft. We routinely try to use the largest possible allograft that will fit in the chest to minimize the need for future replacement. Most infants who come to autograft root and Ross-Konno root replacement have some degree of arch and annular hypoplasia, in which case the pulmonary autograft will be significantly larger than the native aortic annulus and the ascending aorta. After the LVOT is reconstructed with the autograft, the location of the pulmonary bifurcation tends to be posterior to the neoaorta. Therefore, to prevent any allograft kinking, coronary artery compression, or anastomotic stricture, it is advisable to extend the opening in the pulmonary bifurcation onto the left pulmonary artery. The homograft is sutured distally to the pulmonary bifurcation with a continuous nonabsorbable suture, and proximally to the right ventricular outflow tract in a similar fashion. However, because of the proximity of the septal perforating branches of the LAD, the posterior sutures are taken only through the endocardium and partial thickness of the myocardium so as not to compromise the septal blood supply.
      Figure thumbnail fx15
      15Finally, because the autograft tends to be much larger than the original aortic annulus, it encroaches onto the right ventricular outflow tract. The allograft then ‘wraps’ itself around the pulmonary autograft and the posterior proximal suture line will be placed onto or near the autograft annulus.
      Figure thumbnail fx16
      16The pulmonary homograft is usually of sufficient size that additional patch augmentation of the RVOT is rarely necessary. After completion of all of the suture lines, the cross-clamp is removed. The patient is then rewarmed and weaned from bypass.

      Results

      Despite the early introduction of both Ross and Konno surgical methods, most of the data on pulmonary autograft use in the youngest patient population has only short term follow-up. The earliest experience with pulmonary autografts comes from the application of the Ross procedure alone in children and young adults. One of the largest series comes from Elkins et al, who looked at their experience with the Ross procedure performed in 86 young patients (mean age of 11).
      • Elkins RC
      • Knott-Craig CJ
      • Ward K
      • et al.
      Pulmonary autograft in children: Realized growth potential.
      Their results were excellent, with 96.5 +/− 2% actu-arial survival at 7 years and 96 +/− 4% freedom from reoperation on the autograft when done by the root replacement technique. More importantly, however, by comparing the size of the aortic annulus to the body surface area, they confirmed growth of the autograft. The Ross-Konno modification represents a subset of patients undergoing a pulmonary autograft replacement in most published reports. Starnes et al have shown excellent results in their series of 24 pediatric patients who underwent a Ross procedure.
      • Starnes VA
      • Luciani GB
      • Wells WJ
      • et al.
      Aortic root replacement with the pulmonary autograft in children with complex left heart obstruction.
      In this group, eight patients had complex LVOTO and required ventriculoplasty as a part of the procedure. There were no perioperative or late deaths, and follow-up echocardiograms showed good functional results (mean f/u of 13.5 +/− months).
      Our own recent reported experience includes 66 patients, with median age of 10.8 years, operated at CHOP between January 1995 and October 1998.
      • Marino BS
      • Wernovsky B
      • Rychik J
      • et al.
      Early results of the Ross procedure in simple and complex left heart disease.
      Twenty-five of these patients had multiple levels of LVOTO, with 17 undergoing a Ross-Konno procedure. There was a single mortality in the entire group, in a patient who underwent a combined Ross-Konno procedure and redo arch reconstruction, and who died suddenly on postoperative day 3 secondary to a cardiac arrhythmia. The most common morbidity seen was arrhythmia, which occurred in 64% of the patients with complex heart disease. However, none of the patients developed complete heart block despite annular enlargement in 19 of 25 patients within the complex group. An earlier experience from St. Louis with the Ross procedure also documented very good functional results.
      • Kouchoukos NT
      • Davila-Roman VG
      • Spray TL
      • et al.
      Replacement of the aortic root with a pulmonary autograft in children and young adults with aortic-valve disease.
      Thirty-three patients (mean age of 31.4) with aortic valve disease underwent a Ross procedure. Serial echocardiograms were obtained and, at a mean follow up of 24 months, showed good autograft function without late onset aortic regurgitation.
      Several other series have shown similar results. Reddy et al report 11 patients, age 4 days to 17 years (median 12 months) who underwent a Ross-Konno operation.
      • Reddy VM
      • Rajasinghe HA
      • Teitel DF
      • et al.
      Aortoventriculolasty with the pulmonary autograft: The “Ross-Konno” procedure.
      There was one early mortality and no late deaths or reoperations. Follow-up ranged from 2 weeks to 16 months with follow-up echo showing mild aortic insufficiency in only one patient. Recently, Ohye et al reported 10 patients with a median age of 16 days and median follow-up of 48 months, who underwent a Ross-Konno procedure.
      • Ohye RG
      • Gomez CA
      • Ohye BJ
      • et al.
      The Ross/Konno procedure in neonates and infants: Intermediate-term survival and autograft function.
      There were no deaths. On follow-up, no annular dilatation was noted and no reoperations for the pulmonary autograft were required. The most recent report is from Eraz et al who presented their combined experience with Konno aortoventriculoplasties and the Ross-Konno procedure including 15 patients who underwent Ross-Konno procedure, ranging in age from 7 days to 15 years (mean of 5.4 years).
      • Erez E
      • Kanter KR
      • Tam VKH
      • et al.
      Konno aortoventriculoplasty in children and adolescents: From prosthetic valves to the Ross operation.
      There was one operative mortality, and one patient required a permanent pacemaker. Follow-up ranged from 5 months to 3.7 years (mean of 2.1 years) with two late deaths. None of the patients required reoperation. Although the follow-up was not as long, these results contrast strikingly with their experience with the Konno procedure with mechanical or biological valve replacement. All of the patients with tissue valves required a reoperation within 10 years, and 48% of the patients with mechanical valves needed additional surgery within 15 years.
      A number of additional case reports and small series have been published describing application of the Ross-Konno procedure to various forms of the LVOTO.
      • Calhoon JH
      • Bolton JWR
      Ross/Konno procedure for critical aortic stenosis in infancy.
      • Hirooka K
      • Fraser CD
      Ross-Konno procedure with interrupted aortic arch repair in a premature neonate.
      • Daenen W
      • Gewillig M
      Extended aortic root replacement with pulmonary autografts.
      • van Son JAM
      • Falk V
      • Mohr FW
      Ross-Konno operation with resection of endocardial fibroelastosis for critical aortic stenosis with borderline-sized left ventricle in neonates.
      • Hvass U
      • Chatel D
      • et al.
      Relief of complex left ventricular outflow tract obstruction with pulmonary autografts.

      Summary

      The technique of aortic valve replacement with the pulmonary autograft was originally described by Ross in 1967. Aortoventriculoplasty was first described by Konno in 1975 and was used for aortic valve replacement using a mechanical prosthesis. Since then, various refinements in both procedures as well as wider availability of cryopreserved allografts have permitted increasing application of the combined surgical approach in infants and small children. The Ross-Konno combination became particularly appealing in the treatment of complex left ventricular tract obstruction that is often not amenable to simpler techniques such as open valvulotomy or balloon valvuloplasty. The Ross-Konno technique offers a number of advantages over the two alternatives of mechanical or allograft valve replacement. It has a low risk of thromboembolism and prosthetic valve endocarditis, and avoids the lifetime anticoagulation requirement and the size limitation seen with the mechanical valves. It also seems to be free of the rapid degeneration observed with the allografts, particularly when placed in the aortic position. However, the primary advantage of the pulmonary autograft over the other two choices is its apparent potential for growth in the aortic position. Confirmed in a number of short to intermediate term follow-up studies, the Ross-Konno technique is at this time the superior option for definitive treatment of a complex LVOTO at an early age.

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        Extended aortic root replacement with pulmonary autografts.
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