The Ross Operation in Children: Effects of Aortic Annuloplasty

Transcription

1 The Ross Operation in Children: Effects of Aortic Annuloplasty Robert D. Stewart, MD, MPH, Carl L. Backer, MD, Neal D. Hillman, MD, Cynthia Lundt, MD, and Constantine Mavroudis, MD Division of Cardiovascular and Thoracic Surgery, and Division of Cardiology, Children s Memorial Hospital, and Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois Background. Autograft dilatation and progressive neoaortic regurgitation after the Ross procedure prompted us to perform routine aortic annuloplasty. The purpose of this review is to evaluate the success of this technical modification in preventing autograft failure requiring reoperation. Methods. From 1994 to 2005, 46 children and young adults with a mean age of years (range, 14 months to 21 years) underwent a Ross procedure; 19 of 46 patients had prior aortic valve surgery. Neoaortic valve function and need for reintervention were compared between patients who had a Ross procedure without annuloplasty (n 20) and those who had an annular reduction prior to the autograft anastomosis (n 26). Results. There were no early or late deaths during a mean follow-up of months. Mean hospital stay was days. Two patients required early intervention (eight days) for significant neoaortic regurgitation; one patient required repair of a left ventricular outflow tract pseudoaneurysm a month after emergent Ross procedure for endocarditis, and one patient required replacement of a stenotic homograft at five years. Five patients (13%) required autograft repair (n 3) or replacement (n 2) for progressive neoaortic regurgitation, two of the 26 patients had reduction annuloplasty (8%), and three of the 20 patients did not (15%) (p 0.6). There was a similar incidence of neo-sinus of Valsalva dilatation 37 mm or greater in patients with (53%) and without (36%) annuloplasty (p 0.5). Conclusions. The Ross procedure remains an excellent option for valve replacement in children and young adults given the alternatives and can be performed with very low mortality. However, in this series of Ross operations in children, routine use of aortic annuloplasty failed to prevent neoaortic regurgitation requiring reoperation. (Ann Thorac Surg 2007;84: ) 2007 by The Society of Thoracic Surgeons Aortic valve replacement in infants and children remains problematic due to inadequate prosthetic valve replacements. Pulmonary autograft replacement of the aortic valve (Ross operation) has become an important alternative that addresses many of the pitfalls of mechanical and prosthetic valves in children [1 4]. The advantages of the Ross operation include the following: (1) reduced thrombogenicity of the autograft obviating the need for anticoagulation, (2) decreased risk of reinfection after valve replacement for endocarditis [5], (3) proven durability [6, 7], and (4) the potential for autograft growth in children [8 11]. With the expanding use of the Ross operation, there has been a heightened awareness of potential long-term complications which include progressive dilatation of the autograft leading to neoaortic valvular regurgitation, neoaortic aneurysm formation, and the need for future pulmonary homograft valve replacement. Concerns regarding aortic annular dilatation and subsequent aortic regurgitation have caused Accepted for publication March 13, Presented at the Poster Session of the Forty-second Annual Meeting of The Society of Thoracic Surgeons, Chicago IL, Jan 30 Feb 1, Address correspondence to Dr Mavroudis, Children s Memorial Hospital, 2300 Children s Plaza, MC22, Chicago, IL 60614; cmavroudis@ childrensmemorial.org. some centers to reduce the frequency with which the Ross operation is performed in children [12]. We had similar concerns due to annular dilatation requiring reoperation early in our series of Ross operations. Since these early failures, we have modified our approach to the aortic annulus. The purpose of this review is to evaluate our results for the Ross operation in 46 consecutive children and young adults and to determine the effect of annular reduction on the incidence of autograft failure requiring reoperation. Patients and Methods This study was approved by the Institutional Review Board (IRB) of Children s Memorial Hospital as a retrospective chart analysis. The IRB waived the need for patient consent. The cardiac surgery database was searched for all patients aged 21 years or younger who underwent a Ross operation. Between January 1994 and December 2005, 46 children and young adults have undergone the Ross operation at our institution. The mean age was years (range, 1.2 to 21 years). An additional 11 patients underwent a Ross-Konno operation during this same period, but are excluded from this review as annular reduction was the focus of the analysis. Forty-one patients had a preoperative diagnosis of con by The Society of Thoracic Surgeons /07/$32.00 Published by Elsevier Inc doi: /j.athoracsur

2 Ann Thorac Surg STEWART ET AL 2007;84: AORTIC ANNULOPLASTY AND THE ROSS OPERATION 1327 genital aortic valvular disease; predominant aortic stenosis (AS) in six, predominant aortic regurgitation (AR) in six, and mixed AS and AR in 29. Five patients (10%) had acquired AR from acute bacterial streptococcal endocarditis that had damaged the aortic valve, four of whom had active infection at the time of surgery. Nineteen patients (40%) had undergone prior surgical aortic valvuloplasty and 11 had a prior aortic balloon valvuloplasty. Twenty-six patients had bicuspid aortic valves and 20 had tricuspid valves. Additional procedures performed at the time of the Ross operation included ventricular septal defect closures (n 3), ascending aortic aneurysm resections (n 2), and plasty of a coronary artery ostial stenosis (n 1). One of the patients with infective endocarditis required resection of vegetations on the anterior leaflet of the mitral valve with reconstruction of the mitral valve. Of the 46 patients, 20 had their native aortic annulus left intact. From 1994 to 1996 reduction annuloplasty was performed sparingly. Based upon results from three early autograft failures we modified our technique to include reduction annuloplasty. Subsequently, the other 26 patients have undergone reduction annuloplasty by the pledgeted technique. Operative Technique We performed the Ross operation in all cases as an autograft root replacement. All patients had intraoperative transesophageal echocardiography (TEE). Since 1999 all patients have had aprotinin administered intraoperatively. Aorto-bicaval, hypothermic (28 C) cardiopulmonary bypass was established with left ventricular drainage through the right superior pulmonary vein. Antegrade and retrograde cold blood cardioplegia were used routinely. The pulmonary autograft was excised from the right ventricular outflow tract removing a 2 to 3 mm rim of muscle. The pulmonary valve annulus and the aortic annulus were measured using calibrated dilators. If the aortic annulus was larger than the pulmonary annulus, the aortic annulus was reduced in size by placing two or three pledget-supported horizontal mattress sutures through the aortic annulus within the noncoronary sinus (Fig 1). The sutures were placed to reduce the aortic annulus to a size that was approximately 1 to 2 mm smaller than the measured pulmonary annulus. If the diameters of the aortic and the pulmonary annuli were similar, the pulmonary autograft was implanted without remodeling of the aortic annulus. The neoaorta was sutured to the remodeled aortic annulus with two layers of running polypropylene suture followed by coronary reimplantation. The primary outcome of this review was the need for reoperation for neoaortic insufficiency. Echocardiographic data were compared as a secondary endpoint. Intraoperative echocardiographic data were available for all patients. Follow-up echocardiographic data from at least six months after Ross operation were available for 31 patients (67%). Categoric data are expressed as means standard deviation. The paired Student t test was used for analysis of the differences between measurements taken after surgery and those at the latest follow-up. Statistical significance is assumed with a p value of less than Fig 1. After sizing the pulmonary autograft in the aortic valve annulus, the size of the aortic valve annulus is reduced with simple interrupted pledget-supported sutures. The small inset shows how the diameter of the aortic annulus has been reduced in size. This illustration shows the beginning of the anastomosis of the autograft to the left ventricular outflow tract. The aortic valve has been removed. (Reprinted from Pediatric Cardiac Surgery, Third Ed, Mavroudis C, Backer CL, eds. Tchervenkov CI, Chu VF, Shum-Tim D., Left ventricular outflow tract obstruction., p. 544, Mosby, Copyright 2003, with permission from Elsevier.) Results Operative Outcomes The mean cardiopulmonary bypass and aortic crossclamp times were and minutes, respectively. The mean postoperative hospital stay was days. The mean follow-up for our cohort of 46 patients was months. There have been no early or late deaths associated with the Ross operation. Six major early complications (13%) occurred. One patient had a phrenic nerve injury, one patient had heart block requiring a transvenous pacemaker implantation, and one patient required reexploration for postoperative bleeding. Two patients required early reoperation for neoaortic insufficiency, both on postoperative day 8. One of these patients was a six-year-old boy who required an autograft valve-sparing David II root replacement using a Hemashield graft (Boston Scientific, Natick, MA). The other early failure was a 3.5-year-old boy who required a neoaortic reduction annuloplasty with improvement of the acute valvular insufficiency. Both of these early failures are considered technical errors and not progressive autograft failures. The final early complication occurred in a 15-year-old female who had an emergent Ross

3 1328 STEWART ET AL Ann Thorac Surg AORTIC ANNULOPLASTY AND THE ROSS OPERATION 2007;84: Table 1. Reoperations for Neoaortic Autograft Failure Repair Interval (yrs) Aortic Annulus (mm) Initial Procedure Autograft Failure Repair Type Age at Ross (yrs) Diagnosis Patient 25-mm St. Jude b valved conduit No annuloplasty Neo-sinus of Valsalva dilatation to 55 mm with severe AR, annulus 25 mm Severe AR, bicuspid AV, s/p balloon valvuloplasty, s/p surgical valvuloplasty Annular dilatation to 20 mm Aortic homograft replacement Reduction annuloplasty to 20 mm 2 a 6.1 Severe AR, s/p conal VSD repair, s/p pericardial aortoplasty 3.7 Annular reduction to 25 mm and autograft valve-preserving root replacement with 26-mm Hemashield c graft (David II) Annular and neo-sinus of Valsalva dilatation with moderate AR 24 No annuloplasty, ascending aortic Hemashield interposition graft Severe AR, moderate AS, ascending aortic aneurysm (5 cm), s/p surgical valvotomy 4.2 Neoaortic valve sparing root replacement with #32 Gelweave Valsalva d graft (David I) 20 Reduction annuloplasty Neo-sinus of Valsalva dilatation with moderate-to-severe AR Severe AR, mild AS, bicuspid AV 11.6 Neoaortic valve sparing root replacement with #30 Gelweave Valsalva d graft (David I) 24 No annuloplasty Annular and neo-sinus of Valsalva dilatation with moderate-to-severe AR Severe AS and AR, bicuspid AV, s/p valvotomy a Second reoperation on patient 2; b St. Jude Medical, Inc., St. Paul, MN; c Boston Scientific, Natick, MA; d Vascutek, a Terumo company, Renfrewshire, Scotland. AR aortic regurgitation; AS aortic stenosis; AV aortic valve, s/p status post; VSD ventricular septal defect. Table 2. Echocardiographic Findings Findings Aortic annulus at Ross (mm) Aortic annulus at follow-up (mm) Neo-sinus of Valsalva 37 at Follow-up (mm) Annuloplasty (n 17) No Annuloplasty (n 11) p Value /17 (53%) 5/14 (36%) 0.5 procedure with debridement of three subannular abscesses after she presented in cardiogenic shock from bacterial endocarditis. She developed a pseudoaneurysm of her left ventricular outflow tract discovered on routine follow-up echocardiography one month postoperatively and required a homograft patch repair of the pseudoaneurysm with preservation of the autograft. Cultures at the time of her reoperation had no growth of bacteria. None of the four patients with active endocarditis have had any evidence of recurrent endocarditis by either blood culture or echocardiogram. Routine anticoagulation has not been used postoperatively in any patients and there have been no clinically evident thromboembolic events. Late Reoperations Six patients (13%) required late reoperation. One patient required reoperation solely for pulmonary valve stenosis. She was an 11-year-old female with Staphylococcus viridans endocarditis with severe AR and a mycotic aneurysm of the sinus of Valsava, who underwent an urgent Ross operation that included an aortic homograft replacement of her pulmonary valve. She developed calcification of the neopulmonary artery with severe stenosis requiring replacement with a pulmonary homograft five years postoperatively. Her neoaortic autograft continues to function well. Five patients required reoperation for neoaortic valve revision (n 3) or replacement (n 2) for autograft failure resulting in significant AR. The details of these patients are listed in Table 1. There was a similar prevalence of autograft failure between patients with a bicuspid aortic valve (3 of 26, 12%) and those with tricuspid valves (2 of 20, 10%, p 0.9). There was no difference between the annuloplasty and no annuloplasty groups in the prevalence of reoperation for autograft failure; 3 of 20 patients who did not have reduction annuloplasty (15%) compared with 2 of 26 patients who had annular reduction (8%), p 0.6. Echocardiographic Data The echocardiographic findings of the 31 patients with follow-up data from at least six months after the Ross operation are depicted in Table 2. When compared with intraoperative measurements, there was a significant increase in the measured size of the aortic annulus at follow-up in both patients with and without an annuloplasty. However, while the size of the aortic annulus was statistically slightly smaller in the no annuloplasty group

4 Ann Thorac Surg STEWART ET AL 2007;84: AORTIC ANNULOPLASTY AND THE ROSS OPERATION 1329 at baseline, the mean annular size was still approximately 2 mm smaller than the annuloplasty group at follow-up, though there was no statistical difference in those dimensions. More significant than the equivalent annular sizes between the two groups was the size of the neo-sinus of Valsalva. A measurement 37 mm or greater was considered significant for root dilatation based on a published report [13]. There was a similar number of patients with annuloplasty (53%) and without annuloplasty (36%, p 0.5) who had had significant root dilatation. Comment This review of 46 children and young adults who underwent the Ross procedure at our institution over an 11-year period adds to the growing body of literature demonstrating that the Ross is a relatively safe and effective treatment for aortic valvular disease in the young. Very low mortality and low morbidity can be achieved even when 40% of the patients had prior aortic surgery and 10% had active acute bacterial endocarditis. However, these data also show that the Ross procedure is far from a perfect operation. Six of 46 (13%) patients had an early major complication and six patients (13%) required late reoperations, five for autograft failure manifested as progressive AR (11%). David and colleagues [14] pointed out the importance of intraoperative measurements of the aortic and pulmonary annulus along with reducing the aortic annulus size when the aortic annulus is greater than the pulmonary annulus. Their belief is that postoperative aortic regurgitation is due to a geometric mismatch between the diseased aortic valve and the normal pulmonary valve. Our early failures of the Ross operation led us to pay particular attention to the pulmonary-aortic geometry at the time of the operation. By reducing the annulus with simple interrupted pledget-supported sutures at the level of the noncoronary cusp, potential for continued growth of the annulus is maintained. In this series, however, despite correcting autograft-toaortic annular geometry, autograft failures occurred in patients who had a reduction annuloplasty. The incidence among the patients who had annuloplasty is statistically similar to those who did not have annuloplasty (8% vs 15%), and so annuloplasty did not have a protective effect. It is clear that reduction annuloplasty does not prevent dilatation of the autograft at the level of the sinus. The degree of sinus dilatation was similar for both the annuloplasty and nonannuloplasty groups. Dilatation of the autograft after the Ross procedure has been well-documented and is progressive. Simon- Kupilik and associates [13] and Luciani and associates [15] found that freedom from autograft dilatation at one, five, and seven years were 80%, 48%, and 45% and 99%, 65%, and 42% respectively. The majority of the dilatation was at the level of the sinus and sinotubular junction. Interestingly, both authors concluded that despite the very high prevalence of autograft dilatation, the majority of patients did not develop AR. In our series we found autograft dilatation in the majority of patients, but with the greatest dilatation occurring at the level of the neosinus of Valsalva. Yet, like the findings noted above, only three patients who have not undergone autograft revision have greater than mild AR at follow-up despite the prevalence of autograft dilatation. It is possible, however, that the association between autograft dilatation and AR will become stronger with time. Kouchoukos and associates [16] reported only 12 autograft reoperations among 119 patients at 2 to 140 months from time of initial operation. Amazingly, as noted in their addendum from the time of data preparation to publication, six additional patients required surgery for dilatation of the autograft and significant AR. They found progressive dilatation of the neo-sinus of Valsalva and sinotubular junction, but not at the annulus, presumably due to use of pericardial or polytetrafluoroethylene reinforcing strip at the annular suture line. Failed autografts lend themselves to repair rather than replacement because the prominent mechanism for development of AR after the Ross procedure is dilatation of the sinus of Valsalva, as opposed to semilunar cusp degeneration. In this series we performed valve-sparing autograft revisions on three of the five patients. Only one patient had degenerated valve cusps and, despite an effort to correct recurrent AR with a David II valvesparing procedure, he required a root replacement in less than two years. The only other patient who did not have a valve-sparing autograft revision presented at seven years with a massively dilated annulus and neo-sinus of Valsalva due to an unrecognized recurrent aortic coarctation. Along with the experience with our own autograft failures, we have revised three Ross operations performed at other institutions and in two of the three we were able to spare the valve. Our current operation of choice for autograft failure is the David I with valvar resuspension within a Gelweave Valsalva graft (Vascutek, Renfrewshire, Scotland). While technically challenging to get the proper height and orientation of the resuspended valves, the inclusion of the valve within a Dacron tube eliminates future dilatation. Overall, five of the eight (63%) autograft revisions we performed were valve-sparing procedures. Conclusion We believe the Ross operation is, and should continue to be, an important procedure for the treatment of aortic valve stenosis and regurgitation in the pediatric patient. However, neo-sinus of Valsalva dilatation and neoaortic regurgitation remain serious shortcomings of the procedure. This study fails to demonstrate that reduction annuloplasty prevents the occurrence of these problems and a similar number of patients will require reoperation for neoaortic failure with or without reduction annuloplasty. Autograft failure and AR due to dilatation can frequently be corrected with an autograft valve-sparing procedure.

5 1330 STEWART ET AL Ann Thorac Surg AORTIC ANNULOPLASTY AND THE ROSS OPERATION 2007;84: References 1. Williams MA. Tissue valves in young patients--a recipe for disaster. J Card Surg 1991;6(4 suppl): Gallo R, Kumar N, Prabhakar G, al-halees Z, Duran CM. Accelerated degeneration of aortic homograft in an infant. J Thorac Cardiovasc Surg 1994;107: Yankah AC, Alexi-Meskhishvili V, Weng Y, Schorn K, Lange PE, Hetzer R. Accelerated degeneration of allografts in the first two years of life. Ann Thorac Surg 1995;60(2 suppl): S Clarke DR, Campbell DN, Hayward AR, Bishop DA. Degeneration of aortic valve allografts in young recipients. J Thorac Cardiovasc Surg 1993;105: Niwaya K, Knott-Craig CJ, Santangelo K, Lane MM, Chandrasekaran K, Elkins RC. Advantage of autograft and homograft valve replacement for complex aortic valve endocarditis. Ann Thorac Surg 1999;67: Elkins RC, Knott-Craig CJ, Ward KE, Lane MM. The Ross operation in children: 10-year experience. Ann Thorac Surg 1998;65: Rubay JE, Buche M, El Khoury GA, et al. The Ross operation: mid-term results. Ann Thorac Surg 1999;67: Elkins RC, Knott-Craig CJ, Ward KE, McCue C, Lane MM. Pulmonary autograft in children: realized growth potential. Ann Thorac Surg 1994;57: Pessotto R, Wells WJ, Baker CJ, Luna C, Starnes VA. Midterm results of the Ross procedure. Ann Thorac Surg 2001; 71(5 suppl):s Solymar L, Sudow G, Holmgren D. Increase in size of the pulmonary autograft after the Ross operation in children: growth or dilatation? J Thorac Cardiovasc Surg 2000;119: Simon P, Aschauer C, Moidl R, et al. Growth of the pulmonary autograft after the Ross operation in childhood. Eur J Cardiothorac Surg 2001;19: Laudito A, Brook MM, Suleman S, et al. The Ross procedure in children and young adults: a word of caution. J Thorac Cardiovasc Surg 2001;122: Simon-Kupilik N, Bialy J, Moidl R, et al. Dilatation of the autograft root after the Ross operation. Eur J Cardiothorac Surg 2002;21: David TE, Omran A, Webb G, Rakowski H, Armstrong S, Sun Z. Geometric mismatch of the aortic and pulmonary roots caused aortic regurgitation after the Ross procedure. J Thorac Cardiovasc Surg 1996;112: Luciani GB, Casali G, Favaro A, et al. Fate of the aortic root late after Ross operation. Circulation 2003;108(suppl II): II Kouchoukos NT, Masetti P, Nickerson NJ, Castner CF, Shannon WD, Davila-Roman VG. The Ross procedure: longterm clinical and echocardiographic follow-up. Ann Thorac Surg 2004;78: INVITED COMMENTARY The Ross operation was introduced in 1967 by Donald Ross. It became an important alternative for prosthetic valves in patients who needed aortic valve replacement. The major advantages are that it has low thrombogenicity resulting in avoidance of anticoagulant therapy and the potential to grow in children. Patients who benefit most from the Ross operation are children, young adults with an active lifestyle that can interfere with anticoagulant therapy, and women in childbearing age. Despite these advantages, long-term follow-up studies now show substantial reoperation rates. The main reasons for reoperation are the degeneration of the allograft in the pulmonary position and aortic root dilatation leading to progressive aortic insufficiency. Some studies describe better results by using the subcoronary implantation technique or the inclusion cylinder technique. However, as yet there is no definite answer to the high incidence of autograft failure in these patients. In their study, Stewart and colleagues [1] report the effects of aortic annuloplasty on aortic root dilatation in a group of children who underwent the Ross operation. In patients in whom the aortic annulus was larger as compared with the pulmonary autograft, the authors developed a reduction annuloplasty technique and reduced the size of the aortic annulus to 1 to 2 mm smaller than the measured pulmonary annulus. Twenty-six children and young adults who did undergo the annuloplasty technique were compared with 20 patients who had a Ross procedure without annuloplasty. During months of follow-up, all patients remained in good health and there was no early or late mortality. However, 5 patients required reoperation for neoaortic valve revision or replacement for autograft failure resulting in significant aortic regurgitation. There was no difference in the rate of reoperation between the annuloplasty and no annuloplasty groups. Even more, the frequency of aortic root dilatation was similar between these two groups. The authors concluded that their study failed to demonstrate that reduction annuloplasty prevents the occurrence of aortic root dilatation and neoaortic regurgitation in patients undergoing the Ross operation. Although the annuloplasty technique as described by the authors did not result in prevention of aortic root dilatation, this study again shows the very low mortality and good long-term survival after the Ross operation. Despite its shortcomings, the Ross operation still remains an important operation for aortic valve replacement, especially in young children and women of childbearing age. Future studies may include newer technologies as tissue engineering, and hopefully are able to combine the good survival rates with prevention of aortic root dilatation. A. D. J. Ten Harkel, MD, PhD Erasmus MC-Sophia Department of Pediatric Cardiology Dr Molewaterplein 60 Rotterdam, 3015 GJ the Netherlands a.tenharkel@erasmusmc.nl Reference 1. Stewart RD, Backer CL, Hillman ND, Lundt C, Mavroudis C. The Ross operation in children: effects of aortic annuloplasty. Ann Thorac Surg 2007;84: by The Society of Thoracic Surgeons /07/$32.00 Published by Elsevier Inc doi: /j.athoracsur