The Ross Procedure: Pulmonary autograft replacement of the aortic valve

Extended Root Replacement

In those patients with an aortic annulus diameter that is within the 70% confidence limits of the aortic annulus size for the patient's body surface area [3], the operation is done using the following technique.

1. CANNULATION
   Bicaval cannulation is used in all patients with insertion of the superior vena cava cannula relatively high in the vena cava. This allows for excellent exposure of the aortic valve, avoids problems with an "air lock" when the outflow tract of the right ventricle is being reconstructed, and allows opening of the right atrium for direct cannulation of the coronary sinus if necessary. Ascending aortic cannulation is accomplished near the origin of the innominate artery unless the ascending aorta is dilated. If the ascending aorta is aneurysmal or significantly dilated, aortic cannulation is accomplished in the transverse aortic arch. A left ventricular vent is inserted through the right superior pulmonary vein.
   
2. MYOCARDIAL PROTECTION
   Moderate systemic hypothermia is utilized (28-30 deg. C) with cold antegrade blood cardioplegia for induction and intermittent retrograde blood cardioplegia for maintenance. Right ventricular protection is enhanced with ice saline slush. Myocardial temperature is maintained below 15 deg. C.
   
3. AUTOGRAFT HARVEST
   With the heart arrested, the pulmonary artery is opened at the origin of the right pulmonary artery with a transverse arteriotomy (Fig. 1).

   Careful visual inspection of the pulmonary valve should identify three leaflets with minimal fenestration (Fig. 2). The presence of a bicuspid or quadricuspid pulmonary valve or the presence of large (greater than 5 mm) fenestrations or multiple (5 or more) fenestrations preclude a Ross Operation. The incidence of an abnormal pulmonary valve has been 2% in our experience. The main pulmonary artery and its normal contained valve is harvested by completing the transverse arteriotomy and beginning the dissection of the pulmonary artery in a posterior plane, staying adjacent to the pulmonary artery. The left main coronary artery, the anterior descending coronary artery and the first septal perforator must be identified and protected. It may be helpful to open the aorta and place a flexible probe in the left main coronary artery in the reoperative patient or when the surgeon is beginning his experience. This dissection continues close to the pulmonary artery until septal musculature is encountered (Fig. 3). The attachment of the pulmonary artery and the aorta at their common conal tissue may be difficult to dissect, and the surgeon should avoid injury to the autograft by dissecting into the aortic wall if necessary. When septal musculature is encountered, the surgeon, looking through the pulmonary valve into the right ventricle, identifies a point 3 to 4 mm below the pulmonary artery annulus and, using a right-angled clamp, elevates the free wall of the right ventricle and a ventriculotomy is performed (Fig. 4). With the pulmonary valve visualized, the right ventricle is divided 3 to 4 mm below the annulus. Where the right ventricle becomes adherent to the ventricular septum, the dissection is kept superficial and only right ventricular musculature is divided to avoid injury to the first septal perforator of the anterior descending coronary artery (Fig. 5). After completion of the dissection and harvesting of the autograft, it is prepared for implantation. When the autograft is used as a root replacement, all adventitia is left on the autograft and the proximal musculature attached to the pulmonary valve annulus is trimmed in a plane 3 to 4 mm below the nadir of the three coronary sinuses.

4. AUTOGRAFT IMPLANTATION
   The aortotomy should be transverse and located about 2 cm above the origin of the right coronary artery. After careful excision of the aortic valve and any subvalvar obstruction, the aortic annulus is debrided, removing all calcification. The aortic annulus is sized with an aortic valve sizer or a calibrated dilator (Hegar uterine dilator). The left and right coronary arteries are then mobilized with large cuffs of aortic wall. Minimal dissection of the coronary arteries is usually required. The remaining proximal aorta is then excised to the level of the aortic annulus in the nadir of the coronary sinuses and removal of the commissural attachment in the inter-leaflet triangle. The pulmonary autograft is positioned so the posterior sinus of the pulmonary valve becomes the left coronary sinus. Interrupted sutures of 4-0 polypropylene are placed between the nadir of the pulmonary sinuses and the nadir of the aortic sinuses, unless the aortic annulus is markedly dysplastic. These sutures are used to trifurcate the aortic annulus, beginning with the first suture placed below the left coronary ostium, the second suture adjacent to the right coronary ostium and the remaining suture trifurcating the aortic annulus (Fig. 6). The three sinuses of the pulmonary valve are symmetrical and the proximal suture line should attempt to maintain this anatomic symmetry. In adult patients, the proximal suture line is interrupted, tied over a thin strip of pericardium; in the children, in whom we anticipate growth, the suture line is running Polyglyconate, Maxon® (Davis+Geck, Manati, PR).

   After completing the proximal suture line, the left coronary ostium is implanted to a 5 mm opening made in the mid-point of the neo-left coronary sinus (Fig. 7). This suture line is a running 5-0 polypropylene. If the patient is a young child, a 4 mm opening is made and the suture line is 6-0 Maxon. The autograft is then trimmed for the distal suture line, leaving 4 to 5 mm of pulmonary artery distal to the sino-tubular junction of the pulmonary artery. The distal suture line is then completed with a running 4-0 polypropylene suture. If the ascending aorta is dilated, a vertical aortoplasty is completed prior to completing the distal anastomosis (Fig. 8a). The aorta should be reduced in size so that it approximates the size of the sinotubular junction of the pulmonary autograft (Fig. 8b). If the ascending aorta is aneurysmal, the aorta is resected to the level of the innominate artery and replaced with a collagen filled dacron graft of appropriate size. In general, the dacron graft should be the size of the aortic annulus or 2 to 3 mm smaller (Fig. 9). After completing the distal anastomosis to the aorta, the autograft is distended with cardioplegia and the site for implanting the right coronary artery is selected, being careful to avoid kinking of this coronary artery. A 5 mm opening is made in the autograft and after trimming the aortic cuff of the right coronary artery it is sewn to this opening with a running suture of 5-0 polypropylene (Fig. 10). The aortic cross clamp is removed and the remainder of the operation is accomplished during rewarming.

   A pulmonary homograft of appropriate size, 4 to 6 mm larger than the aortic annulus, is trimmed and the proximal anastomosis of the right ventricular outflow tract is accomplished with 4-0 polypropylene. This suture line is completed while cardiac activity is limited so that accurate placement of the suture line to the right ventricular septum can be accomplished. Injury to the septal coronary arteries must be avoided while completing this suture line. With completion of the proximal homograft suture line, hemostasis of the bed of the autograft dissection is accomplished prior to completion of the distal homograft to pulmonary artery anastomosis.

5. De-airing and discontinuation of bypass is completed after warming and establishment of adequate cardiac function.

Inclusion Cylinder The operative technique for the inclusion cylinder is similar to that utilized for the root replacement. Cannulation, perfusion, myocardial protection and harvesting the autograft are identical. The inclusion cylinder technique is utilized in patients with an aortic annulus between 22 and 25 mm in diameter, when this is an appropriate aortic annulus size for the patient's body surface area.

1. The transverse aortotomy is extended into the middle of the non-coronary sinus to the level of the aortic annulus. This provides excellent exposure of the aortic annulus (Fig. 11).
   
2. After harvesting the pulmonary autograft, all adventitia is trimmed from the autograft prior to its insertion, and the proximal myocardial rim below the pulmonary valve annulus is trimmed so that it is no more than 3 mm in length and thickness.
   
3. The proximal suture line is interrupted and is similar to the suture line of the root replacement technique (Fig. 12). As the pulmonary valve has three sinuses that are equal in size and the nadir of these sinuses are 120 degrees apart, the patient with a dysplastic or a bicuspid aortic valve and coronary arteries that are 180 degrees apart presents a technically difficult problem for insertion using the inclusion cylinder technique. These patients should have a root replacement if the surgeon does not have extensive experience with this technique. After placement of the proximal sutures, the valve is seated and the sutures are tied with the valve inverted into the left ventricular outflow tract (Fig. 13).
   
4. The autograft is reverted and trimmed for the distal anastomosis, leaving 3 to 4 mm of pulmonary artery distal to the sinotubular junction. The site for attachment of the commissural fixation suture is selected by placing traction to elevate the commissure of the pulmonary autograft and the appropriate site on the host aorta so that equal tension is on both. A horizontal mattress suture is placed through the pulmonary artery 2 mm above the commissure of the pulmonary artery and full thickness of the aorta at the previously identified point. This usually places the sinotubular junction of the pulmonary artery 5 mm or more above the sinotubular junction of the host aorta. The attachment of the commissures to the aorta affects the long term autograft valve function, and therefore the placement of these sutures is very important. They should be very similar in height and should be 120 degrees apart when they have been properly placed. These sutures are not tied until the coronary arteries have been implanted to the pulmonary autograft. The left coronary artery is sutured to a 5 mm opening in the mid-portion of the posterior sinus of the pulmonary autograft with a running suture of 5-0 polypropylene, followed by a similar technique for the right coronary anastomosis (Fig. 14). The commissural sutures are tied and the distal anastomosis of the pulmonary autograft and the host aorta is initiated at the commissure between the right and left coronary sinuses. This suture is placed full thickness of the aorta and the pulmonary artery and tied outside the lumen of the aorta. The suture is then brought into the lumen of the aorta and a running technique is utilized. When the suture line approaches the aortotomy that has been extended into the non-coronary sinus, the suture line is not completed until this portion of the aortotomy has been closed. The closure of this portion of the aortotomy includes a limited full-thickness bite of the autograft in this sinus to insure fixation of the non-coronary sinus of the autograft to the aortic sinus. The distal suture line is then completed and the remaining portion of the aortotomy is completed in the usual fashion (Fig. 15).

Annulus Reduction and Fixation In patients that have reached their adult size and who have an aortic annulus that is greater than their predicted size based on their body surface area by 2 mm or more, an aortic annulus reduction and fixation is accomplished as a modification of the Ross Operation.

1. After excision of the aortic valve and debridement of the aortic annulus if required, two purse string sutures of heavy polypropylene (2-0 or 3-0) are placed in the left ventricular outflow tract. These sutures are one millimeter apart and are in the aortic annulus at the nadir of the coronary sinuses and below the aortic annulus in the inter-leaflet triangle (Fig. 16a & b). Between the commissure between the right and non-coronary sinus and the adjacent commissure between the non-coronary and left coronary sinus, the reduction sutures are in the membranous septum, close to the aortic annulus, to avoid injury to the conduction system. These two sutures are passed external to the aorta in the mid-portion of the non-coronary sinus and through a teflon felt pledget. A calibrated dilator (uterine dilator), sized to equal the expected mean size of the normal aortic annulus for this patient's body surface area, is passed through the annulus into the left ventricle and the sutures are tied snugly, reducing the aortic annulus to the size of the dilator (Fig. 17).
   
2. The Ross Operation is accomplished as a root replacement and the proximal line of interrupted sutures is carefully placed so that it includes the sutures used to reduce the aortic annulus (Fig. 18). The pulmonary autograft is "seated" into the reduced annulus and the sutures of the proximal suture line are tied over an external cuff of woven dacron material 2 to 3 mm thick (Fig. 19). These sutures are carefully tied to ensure apposition of the aortic annulus and the autograft, keeping the dacron cuff external to the anastomosis. The ends of the external cuff of dacron are secured with an additional suture to complete the "fixation" of the aortic annulus.
   
3. Many of the patients with aortic annulus dilatation will also have significant dilatation of the ascending aorta and in some there will be aneurysmal changes in the aorta. In these patients, the aortic cannula is placed in the transverse arch and the aortic cross clamp is placed at the origin of the innominate artery. A decision to replace the ascending aorta or to reduce the aortic diameter with a vertical aortoplasty is based on the degree of dilatation and the pathologic appearance of the aortic wall.
   
4. In either situation, the Ross Operation proceeds with implantation of the left coronary artery and then trimming the pulmonary autograft 3 to 4 mm distal to the sinotubular junction for attachment to the reduced aorta or to an interposition graft used to replace the ascending aorta. If a vertical aortoplasty is performed, the resulting aorta should approximate the sinotubular dimension of the pulmonary autograft. In general this dimension is about 10% less in size than the pulmonary annulus [4] and we have determined the pulmonary annulus size by our aortic reduction annuloplasty. We reduce the size of the aorta to the size of the reduced aortic annulus, or slightly less. The distal anastomosis is completed and the remainder of the operation is completed as described in the section on the technique for root replacement.
   
5. If the aorta is aneurysmal, it is replaced with a knitted dacron graft that is collagen or gel filled so that post-operative hemostasis is not difficult. A graft equal in size to the size of the reduced aortic annulus is used and the distal anastomosis between the distal aorta and the graft is accomplished first. After implantation of the left coronary artery, the autograft is trimmed as previously described and the graft-autograft anastomosis is completed after trimming of the graft. The graft should be trimmed so that with the distention of the graft and autograft when the aortic cross-clamp is removed there will be no "kinking" of the autograft produced by a redundant graft. The site for implantation of the right coronary artery is always selected after completion of the ascending aortic reconstruction and distention of the autograft with cardioplegia so that the right coronary can be implanted without distortion.

Extended Root Replacement (Ross-Konno Operation) Patients with left ventricular obstruction that involves the aortic valve, the aortic annulus and the left ventricular outflow tract may require an aortoventriculoplasty to relieve their obstruction. Most patients in our experience with subvalvar obstruction and aortic valve disease require resection of the subvalvar obstruction and a left ventricular myomectomy with or without a limited annuloplasty for correction of their obstruction. In these patients, the Ross Operation is usually accomplished as a root replacement. In those patients with severe obstruction or when complete relief of the obstruction is uncertain, an aortoventriculoplasty is performed.

1. The operation proceeds as a standard root replacement with cannulation, perfusion and myocardial protection as previously described. The aortotomy includes an extension into the non-coronary sinus to allow good visualization of the left ventricular outflow tract. The aortic valve is carefully excised and all abnormal subvalvar endocardial thickening is excised. The left and right coronary arteries are mobilized and the proximal aorta is excised to the level of the annulus.
   
2. The pulmonary artery is opened at the origin of the right pulmonary artery and the pulmonary valve is inspected. If the pulmonary valve is normal, the pulmonary autograft is harvested in the usual fashion, except that the right ventriculotomy is initiated about one to 1 to 1½ cm below the pulmonary annulus so that the anterior free wall of the right ventricle can be used to "patch" the ventriculotomy of the aortoventriculoplasty.
   
3. After enucleation of the autograft with this segment of the anterior wall of the right ventricle, the ventriculotomy can be initiated in the right coronary sinus, adjacent to the commissure between the right and non-coronary sinus. The ventriculotomy is extended until complete relief of the outflow tract has been achieved. If additional subvalvar resection of obstructing septal muscle is necessary, it can be accomplished at this time. The autograft is then positioned so that the posterior sinus of the pulmonary valve will become the neo-left coronary sinus and the attached segment of the anterior wall of the right ventricle will be used to close the ventriculotomy. The proximal suture line of 5-0 Maxon is placed to attach the nadir of the left coronary sinus to the nadir of the posterior sinus of the autograft. A second suture is placed through the nadir of non-coronary sinus and through the nadir of the right sinus of the autograft. A third suture is at the apex of the ventriculotomy and through the free wall of the right ventricle below the commissure between the right and left sinuses of the autograft. These three sutures orient the autograft properly. The suture at the left coronary sinus is tied and a continuous suture line attaches the aortic annulus to the autograft posteriorly and this suture is tied to the suture in the non-coronary sinus of the aorta. The suture line is continued in the left and right coronary sinuses to the ventriculotomy suturing the aortic annulus to the autograft. The suture line between the ventriculotomy and the right ventricular wall is buttressed with a strip of pericardium (Fig. 20) and this completes the proximal suture line. The remainder of the autograft implantation is similar to the usual root replacement. Insertion of the pulmonary homograft requires the proximal suture line of the homograft to be sewn to the autograft where the right ventricular muscle has been used to close the ventriculotomy. A relatively large pulmonary homograft should be selected and use of the cryopreserved right ventricular muscle to close this enlarged opening in the right ventricle has not been difficult.

IMAGE DISPLAY NOTE Click on any of the figures to view a larger version of the image.

FIGURE 1 The distal pulmonary artery is incised at the origin of the right pulmonary artery. A transverse arteriotomy, adequate to allow careful inspection of the pulmonary artery, is made.1 Back to text

FIGURE 2 The normal tri-leaflet pulmonary valve with three equal sinuses and no significant fenestrations or other abnormalities of the leaflets.1 Back to text

FIGURE 3 Dissection of the pulmonary autograft is initiated on the posterior aspect of the proximal pulmonary artery. Dissection is continued in this plane, adjacent to the pulmonary artery until septal myocardium is encountered. The left main coronary artery and left anterior descending coronary artery are protected.1 Back to text

FIGURE 4 Identification of the anterior right ventriculotomy is facilitated by placing a right angled clamp through the pulmonary valve and indenting the myocardium 3-4 mm below the pulmonary valve annulus. 1 Back to text

FIGURE 5 Completion of the posterior enucleation of the pulmonary autograft from the outflow tract of the right ventricle. The usual location of the first large septal perforating coronary artery. It arises adjacent to the first diagonal coronary artery of the LAD and traverses the septal musculature toward the conal papillary muscle of the tricuspid valve.1 Back to text

FIGURE 6 The pulmonary autograft is in an anatomic position with the posterior sinus of the autograft becoming the neo-left coronary sinus. (The stay suture in this sinus is not shown for clarity.) The remaining sutures for orientation are placed to position the neo-right coronary sinus and to trifurcate the aortic annulus.1 Back to text

FIGURE 7 The left coronary artery is implanted with a continuous suture of polypropylene.1 Back to text

FIGURE 8a & b Elliptical vertical aortoplasty to correct non-aneurysmal aortic enlargement. After excision of aortic tissue, aortotomy is closed with a double row of polypropylene suture.2 Back to text

FIGURE 9 Replacement of an ascending aortic aneurysm with a knitted dacron graft, similar in size to the size of the aortic annulus following annulus reduction. The graft is anastomosed to the pulmonary autograft 4 to 5 mm distal to the sinotubular junction of the autograft. This anastomosis is completed prior to implantation of the right coronary artery so that the autograft can be distended and the proper site for implantation of the right coronary can be selected.2 Back to text

FIGURE 10 Completion of the pulmonary autograft root implantation with selection of site of implantation of the right coronary artery with the autograft distended. The pulmonary homograft reconstruction of the outflow tract of the right ventricle is with two continuous suture lines.1 Back to text

FIGURE 11 Cannulation: Distal aorta, bicaval cannulation with superior vena caval cannula placed through a pursestring in the vena cava, left ventricular vent through the right superior pulmonary vein and retrograde cardioplegia cannula through the right atrium. All illustrations are oriented as seen by a surgeon standing on the right side of the patient.1 Back to text

FIGURE 12 Placement of three polypropylene sutures to orient the pulmonary autograft. The posterior sinus of the pulmonary autograft becomes the neo-left coronary sinus.1 Back to text

FIGURE 13 The autograft is inverted into the left ventricle and the proximal sutures are tied and divided. 1 Back to text

FIGURE 14 The pulmonary autograft is reinverted - horizontal mattress sutures are placed to secure the height and position of autograft (but not tied until the right and left coronary arteries are implanted). An aortic punch (4 or 5 mm) is used to create an opening in the autograft to allow attachment of the coronary artery ostia.[1 Back to text

FIGURE 15 After completion of the coronary artery anastomosis, commissural stay sutures are tied and divided and the distal suture line is initiated at the commissure between the left and right coronary artery. This is continued to the aortotomy extension into the non-coronary sinus. This portion of the aortotomy is closed with a running suture line with the suture including a full thickness "bite" of the non-coronary sinus of the pulmonary autograft.1 Back to text

FIGURE 16a Two purse-string sutures of 2-0 polypropylene are placed at the aortic annulus in the nadir of the coronary sinuses, in the lateral fibrous trigone in the inter-leaflet triangle between the left and non-coronary sinus, in the muscle of the ventricular septum at the commissure between the left and right coronary sinuses and in the membranous septum between the right and non-coronary sinus. The sutures are brought through the aortic annulus external to the aorta in the mid-point of the non-coronary sinus and passed through a felt pledget. FIGURE 16b An opened view of the aortic annulus showing the exact placement of the sutures. Notice the placement of the sutures in the membranous septum to avoid the conduction system.2 Back to text

FIGURE 17 The two sutures are tied over the felt pledget with a graduated dilator in the aortic annulus of appropriate size for the patient.2 Back to text

FIGURE 18 The proximal interrupted suture line includes the annulus reduction sutures at the level of the aortic valve annulus.2 Back to text

FIGURE 19 The proximal suture line is tied over a thin strip of woven dacron graft being careful to keep the dacron material external to the autograft and not between the apposition line of the aortic annulus and the autograft. The two ends of the dacron graft are tied together with the last two sutures to complete the "fixation" of the aortic annulus. 2 Back to text

FIGURE 20 The pulmonary autograft is positioned in an anatomic position, with the anterior free wall of the right ventricle being used to close the ventriculotomy, and the pulmonary root is attached to the aortic annulus in the normal fashion.3 Back to text