Pulmonary valve preservation techniques

The primary goals of pulmonary valve preservation strategies include valvuloplasty in some form, right ventricular outflow tract augmentation, and offloading the right ventricle while maintaining valve competence. Techniques to accomplish these goals as part of an early repair include commissurotomy and rigid bougiennage, commissurotomy, and balloon pulmonary valvuloplasty, which have been shown to be effective in mild-to-moderate pulmonary stenosis and dysplasia.Reference Ring, Kulik and Burke^9–Reference Robinson, Rathod and Brown¹¹ Severely stenotic or dysplastic valves require extensive valvotomy with or without a transannular patch to complete right ventricular outflow tract augmentation. Transannular patching usually results in free pulmonic insufficiency; therefore some groups have advocated for pulmonary cusp patch reconstruction.Reference Bacha¹² This technique creates a large anterior leaflet of either polytetrafluoroethylene or extracellular matrix to maintain some valve competence and shows promise in early- and mid-term reports.Reference Bacha¹² Prosthetic material, whether extracellular matrix or polytetrafluoroethylene, is subject to calcification and deterioration, but the long-term durability of these materials and the clinical course of cusp failure have not been fully elucidated.Reference Turrentine, McCarthy, Vijay, McConnell and Brown^13–Reference Hayabuchi, Mori, Kitagawa, Sakata and Kagami¹⁵

Other groups have implemented extensive valvotomy to avoid the transannular patch technique, and these efforts have been successful in preserving the annular structure of the pulmonary valve.Reference Mavroudis^16–Reference Ilbawi, Idriss and DeLeon¹⁸ Relief of supravalvar pulmonary stenosis is accomplished through the use of a pantaloon patch of the autologous pericardium, as highlighted in Figs 1–3.Reference Mavroudis¹⁶ This is typically performed after ventricular septal defect and atrial septal defect/patent foramen ovale closure during cardioplegic arrest, allowing for precise suture placement at the pulmonary annulus and sinuses of valsalva. The cross-clamp can be removed at any time during reconstruction to minimise ischaemic arrest time. In patients who require concomitant relief of subvalvar tunnel stenosis, a separate prosthetic patch is sometimes necessary to prevent subvalvar right ventricular outflow tract obstruction. This patch is placed far enough into the right ventricular chamber to relieve the stenosis that was not treated by transatrial resection and towards the pulmonary valve annulus. Care is taken to preserve the functional status of the pulmonary valve to take advantage of valve competency. Such methods have resulted in pulmonary valve preservation in up to 70% of patients,Reference Mavroudis¹⁶ comparing favourably with the 40% or fewer noted in previous reports.Reference Hirsch, Mosca and Bove^19, Reference Pigula, Khalil, Mayer, Del Nido and Jonas²⁰

Figure 1

Exposure of the pulmonary valve via a vertical incision superior to the pulmonary valve into the sinuses of valsalva in the event that there is an anterior–posterior orientation of a bicuspid pulmonary valve or into the two facing sinuses if there is a tricuspid pulmonary valve. If the pulmonary valve is bicuspid and oriented in a horizontal position, a linear incision into the facing sinus of Valsalva is made. The incisions are extended to ~1–2 mm from the pulmonary valve annulus. After valvotomy, ventricular septal defect closure and infundibular resection, three interrupted sutures are placed at the incised portion of the pericardial patch and tied. The purpose of these interrupted sutures is to prepare for a subsequent transannular patch across the reconstruction without suture line disruption in the event that the resultant right ventricular pressure proves excessive. Reproduced with permission from Mavroudis C. Pulmonary valve preservation strategies for tetralogy of Fallot repair. Oper Tech Thorac Cardiovasc Surg 2013;18:301-315. Copyright © 2013, with permission from Elsevier.Reference Mavroudis¹⁶

Figure 2

Once the interrupted sutures are placed, a running suture technique is used to complete pantaloon patch augmention of the incised sinuses of valsalva. At this point of the operation, and after the ventricular septal defect and atrial septal defect are closed, the cross-clamp can be removed and the patient can be rewarmed. The left ventricular vent is allowed to drain and the vena cava catheters are allowed to capture the right atrial return without caval tapes. Reproduced with permission from Mavroudis C. Pulmonary valve preservation strategies for tetralogy of Fallot repair. Oper Tech Thorac Cardiovasc Surg 2013;18:301-315. Copyright © 2013, with permission from Elsevier.Reference Mavroudis¹⁶

Figure 3

Artist’s representation of the complete repair. Reproduced with permission from Mavroudis C. Pulmonary valve preservation strategies for tetralogy of Fallot repair. Oper Tech Thorac Cardiovasc Surg 2013;18:301-315. Copyright © 2013, with permission from Elsevier.Reference Mavroudis¹⁶

When the pulmonary valve annulus is too small, the transannular incision can be placed across the right ventricular outflow tract exactly at the anterior commissurotomy, thereby dividing the pulmonary annulus between the two valve leaflets and ensuring valvar leaflet integrity and attachment. This can be accomplished, despite the prior placement of the pantaloon patch owing to the interrupted sutures that were initially placed in this location. The incision can be completed in the supravalvar pericardial patch and extended across the annulus to the body of the right ventricle, as noted in Fig 4. Reference Mavroudis¹⁶Figure 5 shows the placement of the transannular pericardial patch that preserves the two valve leaflets while relieving the right ventricular outflow tract obstruction.Reference Mavroudis¹⁶ These preserved leaflets will grow with the child and may form the substrate of pulmonary valve restoration that will be described in the next section. Of course, this strategy cannot be used in horizontally oriented or unicusp pulmonary valves. These circumstances will require a transannular patch without valve competency, unless other monocusp techniques are used.

Figure 4

Limited ventriculotomy after pantaloon patch pulmonary arterioplasty. Reproduced with permission from Mavroudis C. Pulmonary valve preservation strategies for tetralogy of Fallot repair. Oper Tech Thorac Cardiovasc Surg 2013;18:301-315. Copyright © 2013, with permission from Elsevier.Reference Mavroudis¹⁶

Figure 5

Completion of limited transannular patch after pantaloon patch pulmonary arterioplasty. Reproduced with permission from Mavroudis C. Pulmonary valve preservation strategies for tetralogy of Fallot repair. Oper Tech Thorac Cardiovasc Surg 2013;18:301-315. Copyright © 2013, with permission from Elsevier.Reference Mavroudis¹⁶

Although these advances have spared many patients from the pathophysiologic spiral that accompanies the incompetent pulmonary valve, there remains a subset of tetralogy of Fallot patients for whom the pulmonary valve-sparing technique was not or could not be applied. The management of the incompetent pulmonary valve has stimulated diverse and creative solutions, all of which require an additional procedure. Pulmonary valve replacement with either homograft or heterograft prostheses provides functional improvement and good freedom from reintervention; however, the timing of this procedure is challenging.Reference Fuller²¹ Furthermore, although patients undergoing late pulmonary valve replacement after tetralogy of Fallot repair do demonstrate evidence of right ventricular functional recovery and a decrease in right ventricular end-diastolic volume, their incidence of ventricular arrhythmias and sudden death has not been shown to decrease significantly.Reference Discigil, Dearani and Puga²² Because of this, earlier pulmonary valve replacement has been advocated, but earlier intervention also carries with it the risk of placing a small valve in a growing child and the need for a subsequent valve replacement earlier in the patient’s life. Pulmonary valve replacement is a well-tolerated procedure, however, and the advent of transcatheter pulmonary valve replacement has the potential to minimise reoperative concerns, although long-term data are lacking.Reference McElhinney, Hellenbrand and Zahn²³ Alternatives to traditional pulmonary valve replacement have been proposed to preserve right ventricular function. Polytetrafluoroethylene monocusp conduits and bicuspid valves have been implanted by several groups with promising early data,Reference Quintessenza, Jacobs, Chai, Morrell and Lindberg²⁴ but calcification and leaflet failure have limited widespread adoption to this point.Reference Turrentine, McCarthy, Vijay, McConnell and Brown^13–Reference Hayabuchi, Mori, Kitagawa, Sakata and Kagami¹⁵

Pulmonary valve restoration techniques

To avoid the cycle of subsequent pulmonary valve replacements, efforts have been made to restore pulmonary valve competence after transannular patching. Reports by Papadopoulos et al,Reference Papadopoulos, Esmaeili, Zierer, Bakhtiary, Ozaslan and Moritz²⁵ Mainwaring et al,Reference Mainwaring, Pirolli, Punn and Hanley²⁶ Prêtre et al,Reference Prêtre, Rosser, Mueller, Kretschmar and Dave²⁷ Park et al,Reference Park, Lee, Lee, Kim, Kim and Kim²⁸ and Mavroudis et alReference Mavroudis, Mavroudis and Frost²⁹ have introduced methods by which a previously rendered incompetent pulmonary valve can be made competent. The impetus behind the development of these techniques was the observation that native leaflet tissue often continues to grow after transannular patching, despite valvar incompetence. These authors therefore postulated that through various methods of valvuloplasty and annular remodelling, a pulmonary valve replacement could be avoided with durable results. These techniques have been referred to as pulmonary valve restoration, recycling, late repair, and secondary repair.

Only 41 such repairs have been published in the various case reports and case series to this point, and the surgical methods of reconstruction vary considerably with the anatomy and pathology of each patient. In the largest series of 20 patients, Park et alReference Park, Lee, Lee, Kim, Kim and Kim²⁸ successfully restored competence using leaflet extension of the previously incised leaflet using either fresh autologous pericardium or polytetrafluoroethylene. Papadopoulous et alReference Papadopoulos, Esmaeili, Zierer, Bakhtiary, Ozaslan and Moritz²⁵ successfully implemented valve resuspension similar to the David procedure in two of their patients, whereas most of the other patients were repaired by leaflet extension with fresh autologous pericardium or partial leaflet excision to increase mobility and to allow for coaptation. In one patient, a monocusp valve was fashioned using glutaraldehyde-treated autologous pericardium sewn to a polytetrafluoroethylene patch.Reference Papadopoulos, Esmaeili, Zierer, Bakhtiary, Ozaslan and Moritz²⁵ Mainwaring et al,Reference Mainwaring, Pirolli, Punn and Hanley²⁶ Prêtre et al,Reference Prêtre, Rosser, Mueller, Kretschmar and Dave²⁷ and Mavroudis et alReference Mavroudis, Mavroudis and Frost²⁹ have used similar techniques in reports that require incising the transannular patch (Fig 6),Reference Mavroudis, Mavroudis and Frost²⁹ performing an annuloplasty to allow for coaptation of the two competent leaflets (Fig 7),Reference Mavroudis, Mavroudis and Frost²⁹ and supravalvar reconstruction with a polytetrafluoroethylene patch and closure of the ventriculotomy (Figs 8 and 9).Reference Mainwaring, Pirolli, Punn and Hanley^26, Reference Prêtre, Rosser, Mueller, Kretschmar and Dave^27, Reference Mavroudis, Mavroudis and Frost²⁹ It is important to note that several concomitant procedures were performed in many of the cases, demonstrating that the techniques thus reported need not be performed as stand-alone procedures.

Figure 6

Transannular patch incision, valve exposure, and leaflet inspection. Reproduced with permission from Mavroudis et al. Native pulmonary valve restoration after remote tetralogy of Fallot repair: how to do it. World J Pediatr Congenit Heart Surg 2013;4:422-426. Copyright © 2013, with permission from SAGE publications in association with the World Society for Pediatric and Congenital Heart Surgery.Reference Mavroudis, Mavroudis and Frost²⁹

Figure 7

Placement of a pledgeted suture to approximate the right posterior and left posterior pulmonary commissures to form a competent bicuspid valve after removal of the oftentimes calcified transannular patch. A second pledgeted suture may be placed to reinforce this commissuroplasty if necessary. Reproduced with permission from Mavroudis et al. Native pulmonary valve restoration after remote tetralogy of Fallot repair: how to do it. World J Pediatr Congenit Heart Surg 2013;4:422-426. Copyright © 2013, with permission from SAGE publications in association with the World Society for Pediatric and Congenital Heart Surgery.Reference Mavroudis, Mavroudis and Frost²⁹

Figure 8

Supravalvar pulmonary artery augmentation using either biologic or prosthetic patch material. At this point, valve competence is assessed through the open right ventricular outflow tract. Re-repair can be performed in the event of valvar incompetence. Reproduced with permission from Mavroudis et al. Native pulmonary valve restoration after remote tetralogy of Fallot repair: how to do it. World J Pediatr Congenit Heart Surg 2013;4:422-426. Copyright © 2013, with permission from SAGE publications in association with the World Society for Pediatric and Congenital Heart Surgery.Reference Mavroudis, Mavroudis and Frost²⁹

Figure 9

Closure of the right ventricular outflow tract with running suture technique. A biologic or prosthetic patch may also be used. Reproduced with permission from Mavroudis et al. Native pulmonary valve restoration after remote tetralogy of Fallot repair: how to do it. World J Pediatr Congenit Heart Surg 2013;4:422-426. Copyright © 2013, with permission from SAGE publications in association with the World Society for Pediatric and Congenital Heart Surgery.Reference Mavroudis, Mavroudis and Frost²⁹

Despite the variety of techniques, the short- and mid-term freedom from pulmonary valve incompetence and reintervention has been promising. Papadopoulos et alReference Papadopoulos, Esmaeili, Zierer, Bakhtiary, Ozaslan and Moritz²⁵ published the longest mean follow-up time of 4 years, during which time all patients experienced symptomatic and echocardiographic improvement in right ventricular size and function, and no patient developed pulmonary valve insufficiency or required reoperation.Reference Papadopoulos, Esmaeili, Zierer, Bakhtiary, Ozaslan and Moritz²⁵ The median duration of follow-up in the largest series (Park et alReference Park, Lee, Lee, Kim, Kim and Kim²⁸) was 12 months, during which time all patients had similar findings. Of the patients, two developed pulmonary stenosis that did not require reintervention. These patients had preoperative pulmonary stenosis, which has led groups to avoid repair attempts in patients with significant preoperative stenosis.Reference Park, Lee, Lee, Kim, Kim and Kim²⁸ Mainwaring et alReference Mainwaring, Pirolli, Punn and Hanley²⁶ published a follow up of 4–30 months in five patients, all of whom experienced similar success. Of the patients, two experienced prohibitive postoperative bypass gradients of >40 mmHg and underwent uncomplicated pulmonary valve replacement. Prêtre et alReference Prêtre, Rosser, Mueller, Kretschmar and Dave²⁷ published similar success with a median follow-up of 38 months of eight patients in whom restoration was possible. In four patients, however, restoration was aborted and pulmonary valve replacement was performed. In cases where pulmonary valve replacement was necessary either before or after an attempt was made to restore competence, the authors note that the amount of time on cardiopulmonary bypass required to investigate the valve or to complete the valvar restoration was minimal and conferred no significant morbidity.Reference Mainwaring, Pirolli, Punn and Hanley^26, Reference Prêtre, Rosser, Mueller, Kretschmar and Dave²⁷

It is important to note that not every patient is a candidate for valve restoration. In all published series to date, the foremost implied or denoted inclusion criterion is that the leaflet tissue needs to have been sufficiently preserved to allow for interim growth. Cases where anterior leaflets were damaged or excised at the initial operation would not be suitable candidates for the described restoration techniques. Furthermore, surgical techniques that require annular remodelling such as those used by Prêtre et al,Reference Prêtre, Rosser, Mueller, Kretschmar and Dave²⁷ Mainwaring et al,Reference Mainwaring, Pirolli, Punn and Hanley²⁶ and Mavroudis et alReference Mavroudis, Mavroudis and Frost²⁹ cannot be performed in the setting of significant concomitant pulmonary stenosis, as the procedure will exacerbate this stenosis.Reference Mainwaring, Pirolli, Punn and Hanley^26, Reference Prêtre, Rosser, Mueller, Kretschmar and Dave^27, Reference Mavroudis, Mavroudis and Frost²⁹ In only one study,Reference Prêtre, Rosser, Mueller, Kretschmar and Dave²⁷ there was a discussion of the percentage of patients who are candidates for restoration procedures, and only 15% of patients were deemed candidates.Reference Prêtre, Rosser, Mueller, Kretschmar and Dave²⁷ Further studies are needed to clarify the incidence of patients with anatomy amenable to these techniques.

In summary, pulmonary valve preservation and restoration techniques have been successfully implemented in a variety of patients using several different techniques. Although the short-term data look promising, further studies are needed to assess long-term freedom from reintervention and valvar incompetence to provide a more accurate comparison with conventional pulmonary valve replacement. In the case of pulmonary valve restoration, one must keep in mind that these techniques have been used only in a few centres and only in a relatively small subset of patients. The relative rarity of these procedures may indicate that only a very small subset of the patient population is a candidate for valve restoration at this point; however, more experience is necessary to clarify the role of these promising procedures. It is our hope that by becoming more aware of the successful implementation of these preservative and restorative methods, surgeons will consider all patients as candidates for valve repair much like mitral valve surgery evolved in adults. In those patients where transannular patching is required, the success of the methods presented herein provide an incentive to limit trauma to the pulmonary valve leaflets to maximise the potential for leaflet growth, and thus candidacy for valve restoration in the future.