Ann Thorac Surg 2003;76:1754-1756
© 2003 The Society of Thoracic Surgeons
How to do it
Modified ross procedure for dysplasic ascending aorta
Pierre Michel Roux, MD*a,
Nabil Saad, MDa
a Department of Cardiovascular Surgery, Hôpital Bon Secours, Metz, France
Accepted for publication March 5, 2003.
* Address reprint requests to Dr Roux, Department of Cardiovascular Surgery, Hôpital Bon Secours, 57038 Metz, France
e-mail: pmroux{at}chr-metz-thionville-rss.fr
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Abstract
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We present a modification of the Ross procedure, to help reduce the risk of late pulmonary artery wall dilatation. The strength of this modified technique is its composite graft construction, consisting of a pulmonary valve autograft inserted in a Dacron tube. This composite graft can be used either as a free graft or a mini-root implant.
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Introduction
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Traditionally, the Ross procedure has been the technique of choice for aortic valve replacement in children [1, 2] and has been used frequently in young adults who have anticoagulation contraindications or do not want anticoagulant treatment. More recently, because of mid- and long-term advantages, this technique has become popular for older patients. However, when used for patients with dysplasia or aneurysm of the ascending aorta, the results are disappointing. The Ross procedure carries out a late reoperation risk, because of pulmonary artery wall dilation or autograft dysfunction [3, 4], which are probably less frequent with the aortic root inclusion technique [5].
We describe a modification of the Ross procedure, with the pulmonary autograft implanted as a free graft in a Dacron tube [6]; the full root implantation technique is available as well. The proposed technique avoids the long-term risk of pulmonary artery wall dilation.
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Technique
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The procedure consists of three steps: - Pulmonary procedure: The pulmonary autograft is harvested, and the right ventricle outflow tract is reconstructed with a homograft according to the classical technique, under normothermic cardiopulmonary bypass, with a beating heart and use of bicaval snaring.
- Composite graft construction: The cardiopulmonary bypass is turned off. The diameter of the harvested pulmonary autograft annulus is measured, and a tube with a diameter one size larger than that of the pulmonary annulus is selected. Then, the autograft is trimmed as a stentless valve for subcoronary implantation and inserted into the Dacron tube. Positioning the "free autograft" in the tube requires three mattress sutures to fix it to the Dacron tube, 2 mm above the bottom of the tube (Fig 1).
Attaching the commissures to the tube requires three more suspended commissural mattress sutures, without traction applied (Fig 2).
Then, the pulmonary annulus is sewn to the Dacron tube with a 4-0 monofilament running suture, leaving a 2-mm Dacron cuff to allow later simplified fixation of the Dacron tube alone to the aortic annulus. The Dacron tube is then measured to be tailored to the appropriate length of the ascending aorta. The top of the autograft is fixed to the Dacron tube with the same 4-0 monofilament running suture in a procedure similar to that for stentless valve insertion. The pulmonary composite graft is now completed, this step having required an average of 30 minutes of off-pump time.
- Left ventricular outflow tract procedure: The aortic valve and ascending aorta are replaced by the composite graft under cardiopulmonary bypass and cardiac arrest, by completely excising the coronary buttons. The proximal cuff of the tube is inserted on the aortic annulus by a 3-0 monofilament running suture, positioning the base of the autograft against the aortic annulus, to improve the quality of the pulmonary valve revascularization coming from the aortoventricular junction (Fig 3).
The two coronary ostia are reinserted into the Dacron conduit (Fig 4),
and the distal part of the Dacron tube is then sewn to the distal part of the ascending aorta, to reestablish the continuity of the aortic outflow tract.
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Comment
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Among 18 patients who had undergone operations with the Ross procedure, 2 have undergone the above technique, the first with the full root autograft implantation variant, and the second with the above-described technique. Our preference is the free graft implantation technique, because of the coronary ostia implantation. The two patients are alive and well and have active lives 33 and 25 months after surgery, respectively, and neither has recent echocardiographic evidence for aortic incompetence.
The modified Ross procedure is more time consuming than the classical technique, because of construction of the autograft composite conduit. Thus, to decrease cardiopulmonary bypass time and improve procedure safety, this step is performed off cardiopulmonary bypass. Pulmonary valve viability over time is the main uncertainty of this technique. The vascularization of the pulmonary valve is interrupted on both sides, but, in this modified technique, the possibilities of autograft revascularization are not as clear as in the classical procedure. The distal part of the valve is attached to the tube and cannot be revascularized from the distal part of the aorta. On the opposite side, the base of the autograft is sewn to the Dacron conduit, not to the aortic annulus. Suturing the aortic annulus to the proximal cuff of the Dacron conduit and not to the base of the autograft is easier and faster but may prevent continuity between the aortic and pulmonary valve annuli, and thus the revascularization of the pulmonary autograft.
To avoid the risk of tissue interruption, the distal Dacron cuff is limited to 2 mm, which allows for joining the two annuli as closely as possible and improving the pulmonary artery wall revascularization. In the absence of early autograft dysfunction, the valve viability could probably be maintained because of direct leaflet vascularization from the left ventricular cavity blood, a well-known physiological concept associated with revascularization from the aortoventricular junction. But, it is not clear whether this double vascularization system can provide sufficient blood supply to all the components of the autograft, leaflets, and residual parts of the pulmonary artery wall to maintain the function of the valve. Obviously, only long-term results will confirm the durability of this composite autograft and the safety of the technique.
The rigidity of the linear Dacron tube has been suspected of jeopardizing the aortic valve leaflets, at the end of the systolic leaflet motion, in different surgical procedures, including native aortic valve sparing or stentless bioprothesis implantation. This risk can be avoided by using, as for the aortic root remodelling procedure, a De Paulis vasalva conduit, with neo-Vasalva sinuses, which prevents any shock between the leaflets and the conduit. Because the diameter of the Dacron tube limits enlargement of the valve, this procedure cannot be proposed for children, who require growth of the pulmonary valve. Dilation of the pulmonary autograft annulus or artery wall is a late but severe complication of the Ross procedure, which seems to occur more frequently over time. This complication requires difficult reoperation, on a calcified pulmonary artery wall, and thus decreases the advantages of the Ross procedure.
By scaffolding the pulmonary autograft annulus with a nondeformed Dacron tube, our proposed technique decreases the risk of late dilation of both the pulmonary artery wall and annulus. This modified Ross procedure could have indications for adult patients who require both aortic valve and ascending aorta replacement, excluding the possibility of native aortic valve sparing.
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References
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- Ross D., Jackson M., Davies J. Pulmonary autograft aortic valve replacement: long- term results. J Cardiac Surg 1991;6:529-533.[Medline]
- Eltkins R.C., Knott-Craig C.J., Howell C.E. Pulmonary autograft in patients with aortic annulus dysplasia. Ann Thorac Surg 1996;61:1141-1145.[Abstract/Free Full Text]
- Hokken R.B., Bogers A.J.J., Taams M.A., et al. Does the pulmonary autograft in the aortic position in adults increase in diameter? An echocardiographic study. J Thorac Cardiovasc Surg 1998;113:667-674.
- Takkenberg J.J.M., Zondervan P.E., van Herwerden L.A. Progressive pulmonary autograft root dilatation and failure after Ross procedure. Ann Thorac Surg 1999;67:551-554.[Abstract/Free Full Text]
- David T.F., Omran A., Ivanov J., et al. Dilatation of the pulmonary autograft after the Ross procedure. J Thorac Cardiovasc Surg 2000;119:210-220.[Abstract/Free Full Text]
- Urbanski P.P. Replacement of the ascending aorta and aortic valve with a valved stentless composite graft. Ann Thorac Surg 1999;67:1501-1502.[Abstract/Free Full Text]
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A modification of the Ross procedure to prevent pulmonary autograft dilatation
Eur. J. Cardiothorac. Surg.,
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