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Ann Thorac Surg 2001;71:S340-S343
© 2001 The Society of Thoracic Surgeons

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Autografts, allografts, and biological valves in children

Technical evolution of the Ross operation: midterm results in 186 patients

^a Sana Herzchirurgische Klinik, Stuttgart, Germany
^b Unitas Hospital, Centurion, South Africa

Address reprint requests to Dr Böhm, Sana Herzchirurgische Klinik, Herdweg 2, D-70174 Stuttgart, Germany
e-mail: joboehm{at}z.zgs.de

Presented at the VIII International Symposium on Cardiac Bioprostheses, Cancun, Mexico, Nov 3–5, 2000.

	Abstract

Top Abstract Introduction Patients and methods Results Comment References

 
Background. The Ross operation approaches the ideal aortic valve replacement. Between February 1995 and February 2000 we performed 186 procedures. This article reviews modifications introduced reflecting our experience.

Methods. In all patients the Ross operation was performed as root replacement. Echocardiographic follow-up was complete in 94% of patients.

Results. No operative death or early mortality occurred, nor did thromboembolic or hemorrhagic events. One patient died at 25 months from hemoptysis with pulmonary valve vegetations. Three patients required reoperation for autograft insufficiency. In 1 patient a tethered cusp was repairable and in 2 patients progressive autograft dilatation required autograft replacement. After routinely incorporating support into the aortic annulus and replacing all dilated ascending aorta, autograft dilatation did not recur. For the pulmonary homograft, one outflow patch was placed to relieve a symptomatic gradient. Nine patients with elevated gradients were under observation. Echocardiography revealed autograft median peak systolic gradients of 4.6 ± 2.8 mm Hg, pulmonary homograft gradients of 14.8 ± 9.6 mm Hg, and nil or insignificant regurgitation.

Conclusions. The aortic annulus must be supported and the dilated ascending aorta replaced. Root replacement with a short autograft allows consistent results. Pulmonary homograft dysfunction is rare but unpredictable.

	Introduction

Top Abstract Introduction Patients and methods Results Comment References

 
Since the introduction of the Ross operation by Donald Ross in 1967 [1] clear advantages over mechanical and biological aortic valve prostheses have been demonstrated. Pediatric cardiologists value the growth potential and elimination of systemic anticoagulation. The Ross operation also has clear advantages for adults with active lifestyles or contraindications to anticoagulation. Other advantages contributing to quality of life are the virtual physiologic hemodynamic performance, absence of audible valve clicks, possible endocarditis resistance, and absence of thromboembolic complications and hemolysis [2–6]. Factors which have limited acceptance of the operation are certainly the complexity, limited homograft availability, and unproven long-term function.

In the interim, results have been published of more than 10-years of follow-up with incident free survival of approximately 90% of patients [2, 3]. These results, together with the greater availability of cryopreserved human homografts, as well as the reproducibility and relative simplicity of the free-standing root technique of implantation of the autograft, have allowed a resurgence of popularity and the frequency of using this operation. The advantages of this technique are related to the maintenance of the valve and autograft root as a functional unit thereby achieving predictable competence in a reproducible fashion [4, 7]. However, the Ross operation remains technically more demanding than routine aortic valve replacement with a prosthesis.

From our first Ross operation, all patients were intensively studied and certain subsequent procedural developments not only allowed us the confidence in the expected results but also encouraged us to include a larger spectrum of patients for the operation. In this study we discuss the technical evolution.

	Patients and methods

Top Abstract Introduction Patients and methods Results Comment References

 
Between February 1995 and February 2000, we performed 186 Ross operations at two institutions (mean age, 38.2 years; range, 2 to 62 years; 38 female, 148 male). The diagnosis was aortic stenosis in 46 patients, aortic regurgitation in 71 patients, combined disease in 66 patients, and aortic prosthesis replacement in 3 patients. In 7 patients endocarditis was present, 32 patients had redo procedures, and 36 patients had combined procedures performed.

All the pulmonary autografts, as well as the pulmonary homografts, used to reconstruct the right ventricular outflow tract were inserted as a free-standing root adhering to the following surgical principles as previously published [4, 7].

1. To guarantee optimal cusp apposition, the aortic annulus has to be equivalent or even smaller in diameter to the pulmonary autograft inflow, and it is conscientiously plicated if necessary.
   
2. The autograft is strictly sutured to the strongest tissue available, generally the aortic annulus, and the autograft to annulus anastomosis is routinely supported externally with a collar of prosthetic material.
   
3. The main pulmonary artery in its flaccid state serves as a guide to the eventual diameter of the distal aorta, which is tailored to fit from the sinotubular junction taking care not to unduly stretch the tissue involved.
   
4. The body surface area serves as a guide for the homograft size. Therefore, patients with a body surface area greater than 1.6 m² receive any valve larger than 23 mm, and patients with a body surface area less than 1.6 m² receive any valve between 18 to 23 mm. This was necessary because we do not have a homograft bank, and a single pulmonary homograft was obtained for each patient from different tissue banks throughout Europe, the United States, and South Africa.
   

Cardiopulmonary bypass was conducted at mild hypothermia using antegrade and retrograde cold blood cardioplegia ending in warm reperfusion of the arrested heart. Concomitant procedures were performed first, and then, only when the surgeon was confident of acceptable long-term results of the additional procedure, the pulmonary autograft was harvested and the Ross operation was commenced. Operative details and concomitant procedures performed are listed in Table 1.

Autograft regurgitation was graded according to the method of Perry and colleagues [8]. Pulmonary homograft insufficiency was assessed using the grading of Chan and coworkers [9]. Peak and mean systolic gradients were calculated from Doppler velocity.

	Results

Top Abstract Introduction Patients and methods Results Comment References

 
The mean follow-up was 27 months (standard deviation, 16; range, 1 to 64 months). Seventy seven percent of the patients were studied for 1 year and 51% of the patients for 2 years. Major perioperative complications are listed in Table 2. Seventy percent of the patients improved postoperatively by at least one functional class of the New York Heart Association and 26% of the patients remained in their preoperative state. Echocardiographic results are listed in Table 3.

In one 8-year-old boy, rapid progressive stenosis of the right ventricular outflow tract developed, which required reoperation at 8 months. The whole homograft conduit appeared symmetrically fibrotic and was repaired with an outflow Dacron patch.

Nine patients are under strict observation for elevated pulmonary gradients ranging from 30 to 53 mm Hg but remain asymptomatic.

One patient died 11 months after surgery in a motor vehicle accident. A second patient died of massive hemoptysis from a complicated lung abscess 25 months after the Ross operation; pulmonary homograft endocarditis was discovered at autopsy.

	Comment

Top Abstract Introduction Patients and methods Results Comment References

 
Excellent midterm results with physiologic gradients and clinically insignificant incompetence, or none at all, of the autograft have been achieved in the majority of patients. There were no early deaths, one suspected cardiac-related late mortality and total morbidity was acceptably low. In our opinion the free-standing root technique, meticulously adjusted to size and supported at the annulus, is critical to achieve and maintain consistent competence; this fact is supported by other authors [5, 6].

The 3 patients with autograft regurgitation who had reoperations reflect a learning curve because they were all part of our early experience. The regurgitation was evident and progressive within a year of operation. Initially only patients who required aortic annulus plication for autograft to aortic annulus mismatch received an external buttress with autologous pericardium incorporated into the suture to prevent against dilatation. Autograft failure in 2 patients, in whom the aortic annulus did dilate despite this pericardial support, convinced us to change to an external Dacron strip since 1997, as suggested by others [3, 10]. Prevention of annular dilatation is of cardinal importance. Therefore, all patients subsequently received the Dacron support, whether the aortic annulus was plicated or not. In children further autograft growth must of course be accounted for.

The distal autograft to aorta anastomosis technique has also evolved. The sinotubular junction of the autograft determines the ideal diameter of the distal anastomosis and the autograft is therefore purposely kept short. Any ectatic aorta is removed and we have a very low threshold to replace the ascending aorta with a prosthetic conduit to permanently fix the sinotubular junction. Initially the autograft was harvested close to the pulmonary bifurcation as suggested by others [11]. In our opinion this is incorrect because it often leaves a substantial length of thin-walled main pulmonary artery exposed to systemic aortic pressure [12]. For the same reservations, we now rarely remodel the ectatic ascending aorta to size, as we did initially [7]. Now we prefer to replace the ectatic section when in doubt. Patients with a bicuspid valve receive the same aggressive treatment.

A short harvested autograft allows the use of a short pulmonary homograft in the right ventricular outflow tract, and therefore, a minimum of foreign tissue, which may reduce an immune response and simplify reoperation. The cryopreserved homografts from transplant recipients are usually short, but excellent in quality and serve our purpose well. From the outset we dissected the pulmonary autograft in a scalloped form following the natural pulmonary valve cusp rim with no more than a 2 to 4 mm right ventricular rim of muscle to minimize the risk of late dilatation as described elsewhere [13].

One patient, an 8-year-old boy, required early reoperation caused by right ventricular outflow conduit stenosis. The patient had a previous aortic valve replacement with an aortic homograft. This implies involvement of an immune response because the discharge gradient was unremarkable, but the course was rapidly progressive and well documented. One study suggesting that homografts seem to sensitize recipients might support this assumption [14]. Although unproven, we henceforth advocate the use of immunosuppression regimen for 6 months in patients such as these.

We have 9 asymptomatic patients with elevated right ventricular outflow tract gradients under observation. The surgery was unremarkable and nothing in their case histories suggests a common cause.

In conclusion, excellent midterm results for the Ross operation are achievable when adhering to surgical principles based on the evolved free-standing root technique with a routinely supported aortic annulus, utilization of a short autograft, and correction of a dilated ascending aorta. Elevated gradients on the right ventricular outflow tract are rare but unpredictable.

	References

Top Abstract Introduction Patients and methods Results Comment References

 

1. Ross D.N. Replacement of aortic and mitral valves with a pulmonary autograft. Lancet 1967;2:956-958.
2. Elkins R.C. The Ross operation: a 12-year experience. Ann Thorac Surg 1999;68:S14-S18.
3. Stelzer P., Weinrauch S., Tranbaugh R.F. Ten years of experience with the modified Ross procedure. J Thorac Cardiovasc Surg 1998;115:1091-1100.
4. Botha C.A., Rupp W., Böhm J.O., Roser D., Rein J.-G. The pulmonary autograft (Ross operation) as aortic valve replacement. S Afr Med J 1999;89:C202-C208.
5. Hokken R.B., Cromme-Dijkhuis A.H., Bogers A.J.J.C., et al. Clinical outcome and left ventricular function after pulmonary autograft implantation in children. Ann Thorac Surg 1997;63:1713-1717.
6. O’Brien M.F., Finney R.S., Stafford E.G., et al. Root replacement for all allograft aortic valves: preferred technique or too radical?. Ann Thorac Surg 1995;60:S87-S91.
7. Botha C.A., Roser D., Rupp W., et al. The influence of geometric mismatch between the native aortic, native pulmonary and homograft pulmonary valve on the results of the pulmonary autograft operation. J Heart Valve Dis 1997;6:355-360.
8. Perry G.J., Helmcke F., Nanda N.C., Byard C., Soto B. Evaluation of aortic insufficiency by doppler color flow mapping. J Am Coll Cardiol 1987;9:952-959.
9. Chan K.C., Fyfe D.A., McKay C.A., Sade R.M., Crawford F.A. Right ventricular outflow reconstruction with cryopreserved homografts in pediatric patients: intermediate-term follow-up with serial echocardiographic assessment. J Am Coll Cardiol 1994;24:483-489.
10. Elkins R.C., Knott-Craig C.J., Howell C.E. Pulmonary autografts in patients with aortic annulus dysplasia. Ann Thorac Surg 1996;61:1141-1145.
11. David T.E., Omran A., Webb G., et al. Geometric mismatch of the aortic and pulmonary roots causes aortic insufficiency after the Ross procedure. J Thorac Cardiovasc Surg 1996;112:1231-1239.
12. Plank L., James J., Wagenvoort C.A. Caliber and elastin content of the pulmonary trunk. Arch Pathol Lab Med 1980;104:238-241.
13. Choudhary S.K., Mathur A., Sharma R., et al. Pulmonary autograft. Should it be used in young patients with rheumatic disease. J Thorac Cardiovasc Surg 1999;118:483-491.
14. Schütz A., Fischlein T., Breuer M., et al. Cytoimmunological monitoring after homograft valve replacement. Eur J Cardiothorac Surg 1994;8:609-612.

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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Böhm, J. O. Articles by Roser, D. Search for Related Content PubMed PubMed Citation Articles by Böhm, J. O. Articles by Roser, D. Related Collections Valve disease