Perspective Chapter: Ross Procedure in Adults with Congenital Aortic Valve Stenosis - New Perspectives

Abstract

Congenital aortic valve stenosis represents 3–5% of patients with congenital heart disease. Management options include both transcatheter and surgical. Open valvotomy/valvuloplasty and aortic valve replacement represent the main surgical choices, and while aortic valve repair is preferred, replacement may be the only option for non-repairable valves. Current available replacement options include pulmonary autograft, homografts, and biological or mechanical prostheses. The Ross procedure first introduced in 1967 by Donald Ross utilizes the patient’s pulmonary valve (autograft) as an aortic valve substitute. Despite being technically challenging it carries the advantages of maintaining the growth potentials and freedom from anticoagulation which are important in young patients. The procedure gained wide interest initially, however it fell out of favor due to concerns related to its complexity and risks of creating “two-valve” disease. Recently, long-term data confirmed the Ross procedure excellent outcomes and better survival in comparison to other aortic valve replacement options. As a result, currently it is considered the procedure of choice for young adults with congenital aortic valve stenosis at many institutions. This chapter discusses the technical aspects of the Ross procedure, and its modifications, and available options for the failing Ross, in addition to outcomes and future directions.

1. Introduction

Congenital aortic valve (AV) stenosis is a progressive pathology that can affect up to 5% of patients with congenital heart disease [1, 2]. It can occur in isolation, in association with genetic syndromes, or as a part of a constellation of findings in other defects in up to 20% of patients [3]. The AV in these cases is usually a bicommissural or bicuspid [4, 5], however unicommisurral, unicuspid and aortic annular hypoplasia can also occur. In adolescents and young adults, congenital aortic stenosis may be asymptomatic or present only on exertion in active patients.

The most common presenting symptoms occur secondary to left ventricular outflow obstruction and may include syncope, angina, dyspnea, and heart failure. Endocarditis, and sudden cardiac death can occur as well. In patients with mild (peak gradient less than 40 mmHg) aortic stenosis, 20% go on to develop moderate stenosis in 10 years after diagnosis, which increases to 45% at 20 years [6]. Evaluation with echocardiography, cardiac catheterization, and stress testing allows for prompt diagnosis and proper intervention.

2. Advantages of the Ross procedure in young adults

The Ross procedure entails the use of the patient’s pulmonary root (autograft) to replace the diseased aortic valve/root and reconstruction of the right ventricular outflow tract using a pulmonary homograft. In comparison with simple aortic valve replacement with either mechanical or biological prosthesis, the procedure is more complex and is technically demanding, however it carries several advantages that are particularly important in young adults. This includes great hemodynamics, freedom from anticoagulation, excellent lifestyle, and more importantly better longer-term survival in comparison to any other AV replacement option [7, 8, 9]. One recent meta-analysis of 3516 adults revealed that the Ross procedure is associated with a significant 46% lower all-cause mortality compared to mechanical aortic valve replacement [7]. In fact, long-term data of the Ross procedure shows that it has survival similar to that of the age-matched healthy general population. This makes it the procedure of choice for treating AV disease in young adults by many surgeons.

3. Potential drawbacks of the Ross procedure

No doubt, the Ross procedure is technically demanding and more complex compared to standard AV replacement. Initial concerns were related to higher operative mortality, however this is not supported by recent data, especially if performed at institutions with Ross and aortic root surgical expertise [9]. There is a significant learning curve. The utilization of the Ross procedure peaked in 1990s, when it represented 1.2% of all AV replacements in North America, and subsequently declined to 0.09% in 2010 [10]. A majority of the data surrounding the Ross procedure are from high-volume single center reports; it was noted that only 9 institutions in the Society of Thoracic Surgeons (STS) database complete on average at least 5 Ross procedures per year [11]. A bare minimum volume of 10 to 15 Ross procedures per year is needed to ensure operative safety and success for patients [11].

One of the arguments against the Ross procedure is related to the concept of “two-valve” disease which results in increased need for reintervention and or reoperation which more often complex with higher mortality. Recent technical refinements in the procedure have improved durability and decreased risks of reintervention significantly. Several long-term studies showed lower rate of reinterventions on the neo-aortic root and the pulmonary homograft, ranging from 0.5–1.2% per patient-year. Autograft dilation represents one of the main reasons for repeat intervention after the Ross procedure, however in many of these cases, the neo-aortic valve can be spared. In addition, the current outcomes for the reinforced Ross procedure appear to be encouraging in terms of stability of the aortic root and lack of dilation.

4. Who is the ideal candidate?

Patient selection is key to ensuring success with the Ross procedure, and many of the early failures of the procedure were attributed to poor patient selection. It is important to consider the patient’s age, etiology of the aortic valve disease, and associated comorbidities. While age should be strongly considered, those with life expectancy of at least 15 years should be strongly considered for the procedure. Those young adults with isolated aortic valve stenosis and small annuli appear to be the ideal candidates for the Ross procedure.

5. Contraindications for the Ross procedure

A. Absolute contraindications:

• Connective tissue disorders: collagen vascular disorders and familial aortopathies (Marfan’s Syndrome, Ehlers-Danlos syndrome, Loeys-Dietz syndrome) in addition to some rheumatologic and autoimmune conditions. These conditions have been shown to lead to vasculitic degeneration and earlier autograft failure.

• Anatomic anomalies of the pulmonary valve: these may not be apparent until intraoperative inspection of the autograft.

• Lack of pulmonary autograft: The Ross procedure is impossible in patients with prior truncus arteriosus repair, pulmonary atresia, and those with congenital pulmonary valve lesions.

B. Relative contraindications:

• Aortic/pulmonary annular size mismatch: This has been showing as a predictor for autograft failure.

• Aortic insufficiency: This has also been associated with increased risk of later autograft failure [12]. This may be the concomitant aortic annular dilation, however several recent technical modifications allowed expansion of the Ross procedure in those subset of patients with excellent results and acceptable autograft durability [13].

• Bicuspid aortic valve: Fewer data exists in patients with bicuspid valves undergoing the Ross procedure and this remains a controversial topic, but it is not currently a contraindication [14]. It is thought that the hesitation to perform the Ross in these patients is primarily due to the bicuspid valve’s association with other histopathologic abnormalities of the aorta, placing patients at higher risk for post-Ross aortic dilatations and accelerated autograft failure [15]. The most recent data do not demonstrate an increased risk of pulmonary autograft failure in patients with bicuspid aortic valves [14].

6. Technical details of the Ross procedure

The technical complexity of the Ross procedure stems from several operative steps that are not part of the standard AV replacement operation. This includes dissecting the aortic root, mobilizing the coronary arteries, meticulous harvesting of the pulmonary autograft, coronary artery reimplantation, and finally pulmonary homograft implantation [16]. Thus, not only should operators be well-trained in the intricacies of this procedure, but experience with aortic root surgery is also extremely important for a successful and durable Ross.

Three variations exist for specific techniques to implant the pulmonary autograft, including:

1. The subcoronary technique, the initial strategy used by Donald Ross. This approach is technically difficult due to pulmonary and aortic anatomic variation in both size and commissure alignment [17].

2. The full root replacement technique, associated with higher risk of pulmonary autograft dilatation due to the high pressures of the systemic circulation, initially described by Stelzer and Elkins in the late 1980s [18].

3. The root inclusion technique, the most recent rendition of the procedure [19]. This allows for implantation of the pulmonary autograft within the patient’s own aortic root, reducing the risk of maladaptive remodeling against the pulmonary root. Modifications using a Dacron graft for further reinforcement have also been used [20].

A general overview of the operative steps of the Ross procedure is as follows:

1. Median sternotomy followed by standard cardiopulmonary bypass with aortic and bicaval cannulation (Figure 1).

2. After cardioplegic arrest, the aortic valve is inspected, and decision is made regarding the potential for repair.

3. If the native AV deemed to be irreparable, the pulmonary valve is then inspected via a pulmonary arteriotomy to determine its suitability as an AV substitute (Figure 2).

4. Harvesting and Preparation of the pulmonary autograft

   1. Using a right-angled clamp through the pulmonary valve helps directing the right ventricular free wall incision (Figure 3a). The autograft is then harvested either with scissors or with electrocautery, paying attention to closely related left main and left anterior descending coronary arteries (Figure 3b).

   2. Removal of the autograft posteriorly is more or less, a process of enucleation, paying attention not to injure the first septal perforator artery (Figure 3c).

   3. Once the autograft is harvested, the infundibular muscle is trimmed, leaving only 2–3 mm below the pulmonary cusps that will allow suturing without leaving too much muscle below the valve.

5. Aortic valve cusps are then excised (Figure 4a), and the annulus is debrided.

6. Coronary buttons are then harvested (Figure 4b and c).

7. The autograft is then implanted into the left ventricular outflow tract using one of the techniques described above. This can be done using running (Figure 5a) or interrupted suture techniques with or without pledgets (Figure 5b and c) [16].

8. Coronary artery reimplantation into their respective sinuses of Valsalva of the autograft (Figure 6a and b).

9. The distal anastomosis of the pulmonary homograft is then performed prior to completion of the distal aortic anastomosis, which allows adequate visualization and ensure good hemostasis of the distal homograft to pulmonary branch anastomosis.

10. Distal aortic anastomosis with the native ascending aorta is then completed (Figure 7).

11. Proximal pulmonary homograft to right ventricular (RV) anastomosis is then completed (Figure 8a and b).

12. Weaning from cardiopulmonary bypass, and evaluation of the neo-aortic valve, and the pulmonary homograft is done with transesophageal echocardiography (Figure 9).

13. Hemostasis and chest closure per routine.

Figure 1.

Cardiopulmonary bypass is initiated typically via aortic and bicaval cannulation.

Figure 2.

After initiation of cardiopulmonary bypass, the main pulmonary artery is transected just proximal to its bifurcation and the pulmonary valve is inspected to determine its suitability as an aortic valve substitute.

Figure 3.

Operative steps of harvesting the pulmonary autograft. (a): A right angled-clamp is passed through the pulmonary valve into the right ventricular outflow tract below the nadir of the anterior cusp of the pulmonary valve, (b): using electrocautery or scissors, the autograft is harvested paying attention to the pulmonary cusps location, and the close by left anterior descending coronary artery (marked blue in the photo), and (c): along the posterior harvest line, the autograft is enucleated from the right ventricular outflow tract to avoid injury to the first septal perforator branch of the left anterior descending coronary artery.

Figure 4.

The left ventricular outflow tract is being prepared. (a): Aortic valve cusps are resected, and the annulus is debrided, (b): the left coronary artery button is harvested, and (c): both coronary artery buttons are prepared.

Figure 5.

Different techniques have been used to secure the autograft to the left ventricular outflow tract. (a): Running, (b): interrupted simple, and (c): interrupted pledgeted sutures.

Figure 6.

Once the autograft is secured, the left coronary button is then reimplanted (a), followed by the implantation of the right coronary button (b).

Figure 7.

The distal aortic anastomosis is then performed.

Figure 8.

The pulmonary homograft is being implanted. (a). The distal anastomosis is constructed first. This can be done prior to completion of the distal aortic anastomosis if there is concern related to adequate exposure to ensure proper hemostasis. (b): The proximal anastomosis of the homograft is done to the right ventricular outflow tract. This can be done on beating heart.

Figure 9.

Final appearance of the completed Ross procedure. In this case, the autograft is reinforced with a Dacron graft.

7. Modifications of the Ross procedure

7.1 Technical tips to stabilize the autograft and minimize risk of future dilation

Autograft dilation has been considered the Achilles’ heel of the Ross operation. Early failure of the procedure has been attributed to autograft dilation with or without neo-aortic valve regurgitation. Several tips are important to consider during implantation of the autograft:

1. Trimming of the autograft muscle to a minimum facilitates the implantation of the autograft in to the LVOT. This creates an external supporting layer at the base of the autograft which prevents dilation.

2. The autograft length has to be cut to minimum to decrease the amount of the pulmonary tissue that has the potential for future dilation

3. Replacement of the ascending aorta or a short segment of the ascending aorta is preferred when it is 40 mm or more to prevent dilation of the distal autograft.

4. Stabilization of the sinotubular junction of the autograft with a Dacron strip if the ascending aorta will not be replaced.

5. Using the native non-coronary sinus of Valsalva of the aortic root to externally support the autograft.

6. In those with dilated aortic annulus (most likely in the presence of aortic regurgitation), a strip of Dacron can be used as an annuloplasty and is secured to the left ventricular/aortic junction prior to implantation of the autograft (Figure 10).

Figure 10.

In patients with severe aortic valve regurgitation and dilated aortic annulus. The annulus can be reduced with a Dacron strip that is secured to the left ventricular/aortic junction with multiple interrupted sutures to sinch the annulus prior to implantation of the autograft, thus preventing future dilation of the proximal end of the autograft.

7.2 Ross-Konno procedure

The Ross-Konno procedure provides more or less a radical solution to multilevel left ventricular outflow tract (LVOT) obstruction. It combines autograft aortic root replacement (Ross) with the aortic annular enlargement (Konno-Rastan), thus addressing both valvular and subvalvular obstruction, in addition to aortic annular hypoplasia.

In this version of the procedure, the pulmonary autograft is harvested with a right ventricular infundibular muscle (skirt) that will be used to augment the aortic annulus and the LVOT anteriorly. The aortic annulus and the LVOT are enlarged anteriorly by incising the annulus and the interventricular septum to the left of the right coronary artery button or along the right/left coronary commissure (Figure 11). This procedure carries slightly higher risk of heart block, and it has been modified further to decrease the length of the incision into the interventricular septum (mini-Konno) and to further enlarge the subvalvular area with a septal myectomy.

Figure 11.

Operative photo showing the Konno incision in a patient with small left ventricular outflow tract and significant size mismatch between the aortic and pulmonary annuli. The incision is created across the interventricular septum and to the left of the right coronary artery button.

7.3 Beating-heart harvest of the autograft

The length of the ischemic time with the Ross procedure is longer in comparison to routine AV replacement. To decrease the cross-clamp time, the autograft can be harvested on a beating heart (Figure 12). This, however, requires caution to avoid injury to the autograft valve or the close by coronary arteries. It can be done in cases where the surgeon is confident that the AV cannot be repaired, so initial inspection of the aortic root is not required.

Figure 12.

The autograft is being harvested on a beating heart. This serves to minimize the aortic cross clamp and ischemic time.

7.4 The reinforced Ross

Recently, the autograft has been implanted in a Dacron graft prior to its securement to the LVOT. The theoretical advantage is prevention of future autograft dilation, and it also allows the ease of implantation of the autograft into the LVOT as a routine full root replacement technique which further decreases the complexity of the procedure.

After harvesting the autograft, it is trimmed, and its proximal end is sized with Hegar dilator (Figure 13a). A 3–4 mm are then added to determine the size of the Dacron graft needed. The autograft is then secured proximally (Figure 13b) and distally (Figure 13c) to the Dacron graft using running 5/0 polypropylene sutures and the valve is tested. The reinforced autograft is then secured to the LVOT using running/interrupted polypropylene sutures. Coronary arteries are then reimplanted into the corresponding sinus of Valsalva of the reinforced autograft. This implantation is a three-layer implantation which includes the native coronary artery wall, the Dacron graft, and the autograft wall.

Figure 13.

Operative photos showing the steps taken in reinforcement of the autograft. (a): After harvesting the autograft, its proximal end is sized with the appropriate Hegar dilator, (b) the Dacron graft is usually sized by adding 4 mm to the Hegar size. The autograft is placed inside the Dacron graft, and secured proximally with three running 5/0 polypropylene sutures, and (c): the distal end of the autograft is then secured to the distal end of the Dacron graft with running or interrupted polypropylene sutures.

This technique does not allow growth of the autograft and therefore is only recommended for adults and fully grown patients.

7.5 The loose jacket technique

This is another technique that has been proposed recently to prevent further autograft dilation using autologous tissue. In this modification, the aortic root wall is not resected. The non-coronary sinus of Valsalva of the aortic root is incised all the way towards the annulus. It is then augmented using a teardrop shaped piece of fresh pericardium. The aortic valve is then excised, and autograft is harvested in the standard fashion. The autograft is secured to the LVOT. The coronary buttons are harvested and threaded through corresponding defects into the aortic wall to be reimplanted into the autograft. The distal aortic anastomosis is then completed. Once the pulmonary homograft implantation is completed, the “loose Jacket” is created. This involves suturing the autologous pericardium to the aortic wall and securing it distally to the ascending aorta with multiple interrupted sutures. This theoretically allows further stabilization of the autograft and may prevent future dilation.

7.6 Ross PEARS (personalized external aortic root support) modification

Recently, an external aortic root support has been used in combination with the Ross procedure to stabilize the autograft and prevent future dilation. This personalized prosthesis is designed based on the pulmonary artery and root measurement on preoperative CT scan. No long-term data exist about this technique.

8. Operative risks and current status

Historically there have been mixed results surrounding the early mortality rates after the Ross procedure, which potentially why some institutions do not support the procedure as a first-line option in younger populations. There is likely a volume-outcome relationship that exists with the Ross procedure [10], and a majority of studies which have reported acceptable lower operative mortality rates are from expert centers. The range in operative and early mortality of the Ross in the current era is approximately 0–4% [21, 22]; these differences are possibly due to [1] volume-outcome relationship, [2] patient selection, and [3] which Ross modification techniques are utilized.

One recent study using the Society of Thoracic Surgeons database reported an almost 3-fold greater operative mortality compared to standard AVR (2.7% versus 0.9%) [10]. This statistic was unfortunately partly responsible for declining interest in the procedure over the last decade, however the reason for this increased operative mortality is due to the study’s inclusion of extremely low-volume centers. Only 6 of the 231 institutions included in this study had experience performing at least 5 procedures per year, which has been suggested as the bare minimum needed to begin to achieve competency in this complex operation [10]. These misleading mortality data are contrasted with single institutional experiences frequently reporting early mortality rates less than 1% [7, 8, 23].

9. Long-term outcomes after the Ross procedure

9.1 Freedom from valve complications and long-term survival

The major drawback to the Ross procedures is the possible need of reoperation due to potential failure of both the autograft and/or the pulmonary homograft. This is often referred to the “Achilles’ heel” of the Ross procedure [24]. This could be one of a few reasons why the Ross procedure is not included as a first-line Class Ia recommendation in cardiology and cardiac surgery societal guidelines on AV replacement [25, 26]. Older reports found that after 13 years of follow-up, freedom from autograft and homograft reoperation was 57% and 93% respectively [24]. Of note, when compared to other AVR options, studies have shown that the Ross has superior long-term freedom from valve-related mortality and all-cause mortality compared to mechanical valves (97% vs. 89%) [27, 28]. There are currently no published reports comparing bioprosthetic AVR versus the pulmonary autograft in the Ross, and there is only one randomized trial comparing it to homografts in adult patients [29].

Several studies have compared homografts and autografts in the pediatric population, including prospective randomized clinical trials. One early trial of 182 patients showed improved survival, reduced 30-day mortality, and greater freedom from reoperation [30]. This greater freedom from reoperation benefit was particularly present in the younger age groups, where the autografts had superior outcomes and there was no evidence of autograft structural degeneration. The most recent studies have reported much lower rates of reoperation for both the autograft and the pulmonary homograft, approximately. 0.5%–1.5% per patient-year, which results in approximately 85–95% freedom from reoperation after 10 years [8, 12, 29]. One of the longest-term outcomes studies by Chambers and Ross of 131 patients who underwent the Ross from 1967 to 1984 reported freedom from autograft replacement after 10 and 20 years of 88% and 75% respectively [31]. These excellent autograft outcomes were also shown for freedom from pulmonary reintervention during the same time course, 89% and 80%. Pathologic evaluation of 30 explanted autografts in this study showed only 3 of 30 underwent degenerative changes. One single center study reported overall survival in pediatric patients (mean age 10.1 years) at 5, 15, and 25 years of 96.7%, 94.4%, and 94.4%, respectively [32]. Accompanying these data on freedom from intervention, a randomized control trial of the Ross versus aortic homograft replacement demonstrated patients who underwent the Ross had better short-term quality of life [29]. Thus, even since the early experience with the Ross, long-term outcomes of using a patient’s own ‘living’ valve for aortic valve replacement are superb in growing adolescent and young adult patients when performed at expert centers.

There are currently 9 studies with more than 15 years of follow-up after the Ross procedure which have demonstrated overall survival that parallels that of the general population [16]. Importantly, such superior outcomes have not been seen in the young adult population with other forms of aortic valve replacement, as discussed here.

9.2 Cardiac remodeling after the Ross procedure

Donald Ross originally demonstrated that the pulmonary autograft was the ideal option to replace the aortic valve, compared to aortic allografts or mechanical valves [33, 34]. The same can be said nearly six decades since the procedure was first described. Few studies have tried to identify specific biologic reasons why the Ross appears to offer superior outcomes in patients with congenital aortic valve disease. As Mazine and colleagues point out, the aortic root composed of the annulus, sinuses of Valsalva, sinotubular junction, valve and valve leaflets are all living dynamic structures and have expansile and contractile functions to ensure adequate aortic valvular hemodynamics [16]. In short, the complex aortic structure informs its function. Thus, replacing the aortic valve with something that most closely retains its native tissue properties, as with the pulmonary autograft, offers patients the best opportunity for full restoration of aortic valve functionality.

Based on current research, it is plausible that the pulmonary autograft, through persistent cellular viability and biologic mechanisms, leads to adaptive cardiac remodeling, reducing long-term morbidity in young patients. In fact, on the gene expression level, the specific endothelial cells lining the pulmonary autograft undergo a phenotypic switch to express genes associated with higher left-sided heart systemic circulatory pressures when implanted in the aortic position [35]. This living valve has the capacity to grow as a viable living structure as the patient develops into middle adulthood, unlike with mechanical or other bioprosthetic valves. Its superior hemodynamic performance is likely due to the preservation of valve mobility with the living pulmonary autograft, compared to mechanical valves, bioprostheses and even homografts [36]. One study demonstrated autografts have reduced LVOT peak velocities after valve replacement and reduced left ventricular wall thickness, which was not seen in a comparison to patients who receiving aortic homografts [37, 38, 39]. Beyond these benefits, the Ross procedure is typically used in physically active young adults, and the reason for this is due to the pulmonary autograft’s ability to adapt to aerobic exercise without increasing the neo-aortic valve gradient, thus mimicking normal aortic physiology [40, 41].

Ex-vivo simulations have allowed for in-depth study of the pulmonary valve biomechanics in the Ross procedure [42]. Some have investigated the proteomic signatures that could be responsible for pulmonary homograft failure after the Ross, suggesting the molecular basis for maladaptive pulmonary remodeling [43]. Such computational modeling studies will allow for further identification of how to modify the original procedure in specific patient situations to ensure optimal long-term results of both the neo-aorta the pulmonary homograft.

10. Reoperation after the Ross procedure: managing the failing Ross

Despite the benefits just discussed, reoperation after the Ross procedure is not entirely benign and requires expertise in reoperative surgery similar to cases of patients with adult congenital heart disease. One small single center study reported approximately a 90% 1-year survival after Ross reoperations, which often involve multiple structures [44]. While a patient with congenital aortic stenosis originally presented with one problem, the Ross procedure in effect converts his or her disease into a 2-valve problem. Current research has focused on understanding predictors of valve failure and refining and improving operative technique to avoid the need for early operation.

Ross reoperation can include a complex spectrum of reoperative cardiac surgery in patients with congenital aortic valve disease. These must be performed in experienced centers with higher-than-average volumes and significant aortic experience. One of the largest studies, using the German Ross Registry of 1779 patients, reported a 2.9% reoperative mortality [8]. Data from the Toronto group of 212 patients with 14-years of follow-up demonstrated no reoperative mortality [27].

10.1 Ross reoperation: autograft failure

This is the most common need for reintervention after the Ross procedure [7]. Reasons for failure include [1] primary leaflet failure, and/or [2] dilatation of the annulus, sinuses of Valsalva, and/or sinotubular junction of the autograft. Predictive factors of autograft reoperation include pre-Ross aortic insufficiency, male gender, and aortic annulus diameter greater than or equal to 15 mm/m², and pulmonary-aortic dimension/size mismatch [7]. To take this one step further, it was determined that the majority of the post-Ross neo-aortic root remodeling leading to autograft failure actually occurs prior to patient discharge [45, 46]. This leaves areas for improvement, particularly continuing to research and refine intraoperative technique to ensure optimal long-term outcomes.

Other preoperative predictors of both autograft and pulmonary homograft failure include high systemic and pulmonary pressures [16]. Thus, patients with uncontrolled hypertension or pulmonary hypertension could be poor candidates for this procedure, especially if there is any concern with controlling blood pressure after the Ross. Close follow up with cardiology can prevent maladaptive remodeling by tight control of systolic pressures below <115 mmHg in the first year of the operation [16].

Another consideration is patients with evidence of aortic dilatation on imaging during follow-up but with an otherwise competent and well-functioning neo-aortic valve. There are few cases of dissection in this patient population, thus the specific diameter at which replacement should be considered is unknown; Mazine and colleagues have suggested an autograft diameter of 50 mm is an indication for reintervention [16].

Several options are available to manage the failing autograft:

10.1.1 Valve-sparing autograft root replacement

If the primary failure is the result of the autograft dilation (Figure 14a), the autograft valve can be saved with a valve-sparing root procedure that is similar to patients with Marfan’s syndrome and other aortopathies. The aneurysmal autograft wall is excised leaving the valve (Figure 14b and c), which is then implanted in a Dacron graft in a similar manner to other valve-sparing root procedures (Figure 14d and e). The procedure, however, is a bit more complex and more technically demanding due to the complexity of the dissection required and the adherence between the autograft and the pulmonary homograft from the previous procedure.

Figure 14.

Valve-sparing aortic root replacement (VSRR) is an option to save the autograft valve in those presented with dilated autograft after Ross procedure. (a) Preoperative computed tomography (CT) scan with 3-dimensional reconstruction in a patient who underwent Ross procedure previously showing significant pulmonary autograft dilation, (b) the aneurysmal autograft wall was resected and measures are taken to determine the size of the Dacron graft to be used, (c) the autograft valve is evaluated and appeared structurally normal, (d) the autograft valve is implanted inside the Dacron graft and the commissures are secured to the graft wall, and (e) postoperative CT scan after VSRR.

In some situation, a remodeling technique combined with suture annuloplasty can be utilized. This allows downsizing the annulus without the need for deeper dissection.

10.1.2 Ross reversal

Petterrsson and colleagues in 2007 proposed the concept of “Ross reversal” [47]. This operation is indicated for patients with autograft insufficiency secondary to aortic remodeling including root dilatation, and concomitant pulmonary homograft dysfunction. It consists of transplanting the autograft back to its native pulmonary position, and a composite graft (Bentall), or allograft aortic root replacement. This effectively converts a patient’s Ross-created 2-valve disease back into a 1-valve (aortic) disease [48]. The physiology behind the ability to rescue the failing pulmonary autograft includes the previous remodeling that took place after the initial Ross procedure from constant exposure to higher left-sided systemic pressure and stress [49]. Patients are also more likely able to tolerate pulmonary regurgitation after the native pulmonary valve is restored, compared to aortic insufficiency. Further, the patient’s own living autograft is once again the best option for pulmonary valve replacement, compared to bioprostheses, mechanical, and transcatheter valves.

In 2018, the first early and midterm outcomes from the original Ross reversal operation were published [50]. This study included 39 adult patients, of whom 30 underwent successful Ross reversals. The time from initial Ross to the reversal operation was approximately 12 years (range 5–19 years). There was no major postoperative morbidity, no operative deaths, and no reoperation during the mean follow-up period of four years. A minority of patients (6/30) had moderate to severe pulmonary regurgitation that was clinically insignificant. The Ross reversal represents a new era in Ross research, and long-term outcomes data are needed to understand the safety and overall effectiveness of this novel salvage option.

10.1.3 Personalized external aortic root support (PEARS) procedure

As mentioned previously, PEARS is a personalized external aortic root support that has been designed to support the autograft at the time of Ross procedure and has been also used to salvage the failing dilated autograft. The advantages of this technique is the lack of need for cardiopulmonary bypass and ischemic time, however no long-term data is available yet regarding its outcomes.

10.1.4 Transcatheter aortic valve implantation after Ross procedure

Transcatheter aortic valve implantation for autograft valve regurgitation has been reported. This may present an additional future option for patients with failed Ross. With the progress and improvement in transcatheter valve technology, this may present a valuable option in the future, but long-term data will be needed to prove its effectiveness.

10.2 Ross reoperation: pulmonary homograft failure

Pulmonary homograft failure, most commonly consists of homograft dysfunction from progressive pulmonary stenosis with peak systolic gradients greater than 40 mmHg [51]. An inflammatory process along the pulmonary distal anastomosis has been suggested a potential etiology of the stenosis [52]. Other pathologies of homograft failure include pulmonary insufficiency from leaflet prolapse [53]. Similar to risk factors associated with autograft failure, pulmonary homograft dysfunction can be accelerated from high preoperative pulmonary arterial pressures.

Younger patients, smaller homograft diameters, increases in body surface area during follow-up, and male gender are potential predictors of post-Ross higher peak homograft pressure gradients [54, 55]. Careful attention during the operation should be paid to avoid under-sizing of the pulmonary homograft. In fact, the Toronto group published a series of 212 patients using this technique of homograft oversizing, and at 20-years of follow-up, there was 93% freedom from pulmonary reoperation [7].

Although historically Ross reintervention was primarily a result of pulmonary autograft failure, as the modifications for autograft implantation and reinforcement have become popularized, some studies are now reporting increased rates of pulmonary reintervention in addition to autograft failure. Particularly in younger patients, there is up to a 2-fold increased risk of pulmonary homograft reintervention compared to aortic reintervention [32]. Fortunately, in the current era of transcatheter and percutaneous technology, homograft failure can occasionally be treated with minimally invasive approaches. There is early experience with both the Medtronic Melody valve and the Edwards-Life Sciences Sapien valve in these situations [56, 57, 58] In conclusion, the new era modifications for Ross reinforcement, coupled with an expansion of options for pulmonary reintervention may lead to increased utilization of the Ross procedure over the next few decades.

11. Conclusions and future directions

In this chapter, we have discussed the indications and outcomes of the Ross procedure for young adult patients with congenital aortic valve stenosis. The Ross procedure offers exceptional biologic and hemodynamic results for these patients. This cannot be achieved by using mechanical or other bioprosthetic valves including xenograft or homografts. While there is increased complexity to the Ross procedure compared to the traditional AV replacement, requiring significant operator expertise, thinking about the long-term durability and longevity for young patients is critical.

As we enter a new era of the Ross procedure’s evolution, attention to patient selection is critical to identify and risk-stratify patients who will benefit most from this procedure. Continued research examining predictors of pulmonary homograft failure and consequences of aortic remodeling in these patients is needed. Basic science and computational models to elucidate the hemodynamic benefits of the Ross will also lead to greater understanding of the benefits of the procedure and identify ways to further refine the technique. New options for pulmonary homograft replacement, including transcatheter intervention and even engineered living valves that grow with patients [59, 60] may alleviate some of the main concerns with converting patients with congenital aortic stenosis into a 2-valve disease process after the Ross. Referral of such patients to expert centers is also imperative. Given the recent positive literature surrounding this procedure as discussed in this chapter, it is also possible that there will be an increase in dedicated training for surgeons interested in gaining Ross operative experience. This will allow for expanded access for patients with congenital aortic stenosis and will lead to the opportunity to conduct gold-standard clinical trials using real-world, multicenter, and international experiences.

Conflict of interest

Disclosures/Funding: Dr. Sameh M. Said is a consultant for Cryolife, Abbott and Stryker.