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Complex Pulmonary Artery Reconstruction
Congenital
Complex Pulmonary Artery Reconstruction Michael Ma, MD, Olaf Reinhartz, MD, Richard D. Mainwaring, MD, and Frank L. Hanley, MD Complex Pulmonary Artery Reconstruction evolved through our long-term clinical experience in the surgical management of patients with major aortopulmonary collateral arteries. A midline sternotomy approach, utilizing novel techniques for exposure and mobilization, enables access to the distal pulmonary artery tree to the segmental and subsegmental levels. This allows reconstructive procedures to address both discrete stenoses and areas of long-segment hypoplasia, to reduce pulmonary hypertension and improve and/or preserve right ventricular function. We have utilized this technique in over 70 patients, with our most recent analysis demonstrating one operative mortality, no operative reintervention, and improvement in right to left ventricular pressure ratio from 0.94 (0.72-1.30) to 0.36 (0.190.54) with durable 4 § 3 year follow-up. Operative Techniques in Thoracic and Cardiovasculary Surgery 24:163 175 Ó 2019 Elsevier Inc. All rights reserved. KEYWORDS pulmonary artery, Pulmonary Artery Reconstruction, major aortopulmonary collateral arteries (MAPCAs), Williams syndrome, Alagille syndrome
Introduction
T
hrough our 25-year experience in managing patients with major aortopulmonary collateral arteries via midline sternotomy unifocalization procedures,1 we have developed and refined various techniques to allow for complex Pulmonary Artery Reconstruction (PAR). PAR has become an important therapy for patients afflicted by peripheral pulmonary artery stenosis (PPAS) and/or other phenotypes involving hypoplasia or stenosis of the distal pulmonary artery tree, supplanting existing catheter-based treatment modalities as first-line therapy. Typically, surgery is offered to patients with evidence of significant pulmonary hypertension (>50% systemic pressure), right ventricular strain or reduced function, and/or attributable clinical symptoms. Several technical principles are emphasized in this approach and illustrated in the figures to follow (Figs. 1-8):
2. Division of the branch PAs from each other, and from the main PA, allows for extensive PA tree mobilization to the segmental and subsegmental levels. 3. Longitudinal arteriotomy along the posteromedial surface of each branch PA, carried through to the most posteromedial segment of the lower lobar arteries, allows visualization of each hypoplastic/stenotic branch point, as these vessels originate from the anterolateral aspects of the ongoing PA. 4. Ostial stenoses are treated effectively with “v-plasty” native-native tissue anastomoses, while long-segment hypoplasia improves with longitudinal arteriotomy and PA homograft patch augmentation. Both augmentation techniques allow for interval PA tree growth.
1. Midline sternotomy allows access to both lungs and ease of establishing cardiopulmonary bypass. This is performed via central aortic and bi-caval venous cannulae; the separate superior vena cava drainage ensures appropriate upper body drainage while the right PA reconstruction, which can impact flow in the proximal superior vena cava, is completed.
Stanford University School of Medicine, Department of Cardiothoracic Surgery, Division of Pediatric Cardiac Surgery, Lucile Packard Children’s Hospital, Stanford, CA Address reprint requests to Michael Ma, MD, Stanford University School of Medicine, Department of Cardiothoracic Surgery, Division of Pediatric Cardiac Surgery, 870 Quarry Road, Falk Building, CVRB, Stanford, CA 94305. E-mail: [email protected] 1522-2942/$ see front matter © 2019 Elsevier Inc. All rights reserved. https://doi.org/10.1053/j.optechstcvs.2019.09.004
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Figure 1 (a) Midline sternotomy is utilized to allow access to both pulmonary hila and to facilitate cardiopulmonary bypass (not depicted). (b) The pulmonary tree is dissected extensively within the mediastinum, and the main pulmonary artery is divided. (c) The main pulmonary trunk is oversewn, and retraction sutures are placed to maintain orientation of the distal main pulmonary artery orifice. (d) The branch pulmonary arteries are divided along their natural raphe, and the preplaced retraction sutures are utilized to mobilize each branch extensively.
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Figure 1 Continued
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Figure 1 Continued
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Figure 1 Continued
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Figure 2 Extensive mobilization and dissection of the pulmonary tree is facilitated in an extrapericardial fashion if necessary. The right pulmonary artery can be mobilized lateral to the superior vena cava to improve visualization. Progressive increased retraction on both branch pulmonary arteries allows access to the lobar, segmental, and subsegmental levels, and surrounding pulmonary veins and airways.
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Figure 3 (a) The anterolateral aspect of the branch pulmonary artery gives rise to lobar vessels, with areas of stenosis and/or hypoplasia. (b) The posteromedial surface of the branch pulmonary artery can be opened longitudinally to allow intraluminal visualization of the opposing branches.
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Figure 4 (a) Proximal and distal branches can demonstrate both focal stenoses and long-segment hypoplasia. (b) The vector of branch arteries relative to the ongoing pulmonary artery helps to determine the appropriate reconstructive strategy. Acute take-offs and focal stenoses are more amenable to “v-plasty” (Fig. 5), while obtuse take-offs and long-segment hypoplasia is better served by pulmonary artery homograft patch augmentation (Fig. 6).
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Figure 5 (a) Longitudinal arteriotomy along the posteromedial surface of the pulmonary artery enables intraluminal access to branch points. (b) An ostial stenosis is located. (c) Retraction sutures are placed on either side of the planned “v-plasty.” (d) A planned incision line in the ongoing pulmonary artery is visualized, such that distortion of the smaller branch is minimized. (e) Counter-incisions are made in the ongoing pulmonary artery and in the branch to be augmented. These are extended an equal distance along both vessels, past the point of narrowing within the branch. (f) A fine (8-0) Prolene suture is placed through the distal end of both incisions. (g) Each end of the Prolene is then run in continuous fashion to bring the counter-incisions together in longitudinal fashion. These ends are carefully tied to themselves intraluminally, and the knots cut precisely to avoid excise suture material within the enlarged ostium. (h) The retraction sutures are removed. The ostial stenosis is eliminated, and the functional orifice to the branch is thus enlarged.
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Figure 6 Longitudinal pulmonary artery homograft patch augmentation is performed along the posteromedial arteriotomy to finish each branch pulmonary artery reconstruction. Obtuse take-off branches and long-segment hypoplasia can also be addressed in this fashion. At completion, all areas of stenosis and/or hypoplasia, through to the segmental and subsegmental levels, are improved and/or eliminated. Native-native tissue remains throughout the reconstruction, to ensure ongoing growth potential. The typical branch pulmonary artery reconstruction is depicted, although additional homograft patches may be utilized in select situations.
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Figure 7 Both augmented branch pulmonary arteries are returned to orthotopic position. The initial retraction sutures guide orientation and reconstruction of the original distal main pulmonary artery orifice, with the homograft augmentation returned to a posterior position (not visible). The distal and proximal main pulmonary arteries are reconnected, and the patient weaned from cardiopulmonary bypass (not depicted).
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Figure 8 Cather-based angiography remains the gold standard method for surgical planning to delineate areas of hypoplasia and/or branch stenosis. (a) Pre- and (b) postsurgical images from 1 such patient provide a sense for the degree of reconstruction afforded by this technique, although a complete understanding of each case requires several selective injections into individual lobar/segmental vessels to assess their overall distal pressures and character.
Complex Pulmonary Artery Reconstruction
Discussion Prior to this approach, PPAS and its related phenotypes were managed primarily through catheter-based interventions, with surgery (ie, hilum-hilum branch PA patch augmentation) limited to the intrapericardial branch PAs. Unfortunately, balloon angioplasty often resulted in only modest and transient improvements in right ventricular afterload. Stents seemed to offer a greater duration of short-term gain, at the expense of (1) eventual in-stent restenosis, (2) multibranch loss in the setting of stent obstruction at points of bifurcation, (3) loss of PA growth potential, and (4) mass effect compression to surrounding pulmonary veins and bronchioles. Several single-center series have examined outcomes of this approach,2-4 the largest of which included 69 patients treated over a 25-year period.2 In this cohort, the average right to left ventricular (RV:LV) pressure ratio improved from 1.0 (0.52-2.17) to 0.52 (0.24-1.04) after all interventions, with freedom from death or surgery 38% § 6% at 1 year and 22% § 6% at 5 years. Ten patients ultimately died and 13 required surgical intervention. PAR, which has been employed at our center as first-line therapy for these patients, avoids many of the catheter-based procedural shortcomings listed above, and attempts to provide a definitive and durable repair. The most recent published analysis5 of our cohort included 38 patients who had been treated in this manner, from 2002 to 2016. Underlying syndromes included Williams (n = 20), Alagille (n = 12), other (n = 3), and none (n = 3). Initial RV:LV pressure ratio improved from 0.94 (0.72-1.30) to 0.36 (0.19-0.54) after surgery. One operative mortality occurred in a Williams patient, in the setting of significant left ventricular dysfunction as a sequela of ongoing left-sided obstruction. One patient required Extra Corporeal Membrane Oxygenation for 4 postoperative days in the
175 setting of acute lung injury. At most recent follow-up (4 § 3 years), no long-term mortality has been observed. One patient has required balloon angioplasty of a focal recurrent PA stenosis. RV:LV pressure ratio remains stable at 0.35 § 0.04. We believe that ongoing follow-up for this surgical cohort, which has expanded to over 70 patients, will further validate complex PAR as a mainstay therapy for patients afflicted with PPAS and its related phenotypes. We hope that the outlined principles and stepwise illustrations depicted herein will allow for widespread adoption of PAR to improve outcomes for this critically-ill population of patients.
Acknowledgments The authors thank Michael Leonard, CMI, FAMI, American River College, Sacramento, CA, for preparing the illustrations for this publication.
References 1. Bauser-Heaton H, Borquez A, Han B, et al: Programmatic approach to management of tetralogy of Fallot with major aortopulmonary collateral arteries: A 15-year experience with 458 patients. Circ Cardiovasc Interv 10, 2017:e004952 2. Cunningham JW, McElhinney DB, Gauvreau K, et al: Outcomes after primary transcatheter therapy in infants and young children with severe bilateral peripheral pulmonary artery stenosis. Circ Cardiovasc Interv 6:460–467, 2013 3. Gandy KL, Tweddell JS, Pelech AN: How we approach peripheral pulmonary artey stenosis in Williams-Beuren Syndrome. Semin Thorac Cardiovasc Surg Pediatr Card Surg Ann 12:118–121, 2009 4. Stamm C, Friehs I, Moran A, et al: Surgery for bilateral outflow tract obstruction in elastin arteriopathy. J Thorac Cardiovasc Surg 120: 755–763, 2000 5. Mainwaring RD, Hanley FL: Surgical technique for repair of peripheral pulmonary artery stenosis. Semin Thoracic Surg 28:418–424, 2016
Complex Pulmonary Artery Reconstruction Michael Ma, MD, Olaf Reinhartz, MD, Richard D. Mainwaring, MD, and Frank L. Hanley, MD Complex Pulmonary Artery Reconstruction evolved through our long-term clinical experience in the surgical management of patients with major aortopulmonary collateral arteries. A midline sternotomy approach, utilizing novel techniques for exposure and mobilization, enables access to the distal pulmonary artery tree to the segmental and subsegmental levels. This allows reconstructive procedures to address both discrete stenoses and areas of long-segment hypoplasia, to reduce pulmonary hypertension and improve and/or preserve right ventricular function. We have utilized this technique in over 70 patients, with our most recent analysis demonstrating one operative mortality, no operative reintervention, and improvement in right to left ventricular pressure ratio from 0.94 (0.72-1.30) to 0.36 (0.190.54) with durable 4 § 3 year follow-up. Operative Techniques in Thoracic and Cardiovasculary Surgery 24:163 175 Ó 2019 Elsevier Inc. All rights reserved. KEYWORDS pulmonary artery, Pulmonary Artery Reconstruction, major aortopulmonary collateral arteries (MAPCAs), Williams syndrome, Alagille syndrome
Introduction
T
hrough our 25-year experience in managing patients with major aortopulmonary collateral arteries via midline sternotomy unifocalization procedures,1 we have developed and refined various techniques to allow for complex Pulmonary Artery Reconstruction (PAR). PAR has become an important therapy for patients afflicted by peripheral pulmonary artery stenosis (PPAS) and/or other phenotypes involving hypoplasia or stenosis of the distal pulmonary artery tree, supplanting existing catheter-based treatment modalities as first-line therapy. Typically, surgery is offered to patients with evidence of significant pulmonary hypertension (>50% systemic pressure), right ventricular strain or reduced function, and/or attributable clinical symptoms. Several technical principles are emphasized in this approach and illustrated in the figures to follow (Figs. 1-8):
2. Division of the branch PAs from each other, and from the main PA, allows for extensive PA tree mobilization to the segmental and subsegmental levels. 3. Longitudinal arteriotomy along the posteromedial surface of each branch PA, carried through to the most posteromedial segment of the lower lobar arteries, allows visualization of each hypoplastic/stenotic branch point, as these vessels originate from the anterolateral aspects of the ongoing PA. 4. Ostial stenoses are treated effectively with “v-plasty” native-native tissue anastomoses, while long-segment hypoplasia improves with longitudinal arteriotomy and PA homograft patch augmentation. Both augmentation techniques allow for interval PA tree growth.
1. Midline sternotomy allows access to both lungs and ease of establishing cardiopulmonary bypass. This is performed via central aortic and bi-caval venous cannulae; the separate superior vena cava drainage ensures appropriate upper body drainage while the right PA reconstruction, which can impact flow in the proximal superior vena cava, is completed.
Stanford University School of Medicine, Department of Cardiothoracic Surgery, Division of Pediatric Cardiac Surgery, Lucile Packard Children’s Hospital, Stanford, CA Address reprint requests to Michael Ma, MD, Stanford University School of Medicine, Department of Cardiothoracic Surgery, Division of Pediatric Cardiac Surgery, 870 Quarry Road, Falk Building, CVRB, Stanford, CA 94305. E-mail: [email protected] 1522-2942/$ see front matter © 2019 Elsevier Inc. All rights reserved. https://doi.org/10.1053/j.optechstcvs.2019.09.004
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Figure 1 (a) Midline sternotomy is utilized to allow access to both pulmonary hila and to facilitate cardiopulmonary bypass (not depicted). (b) The pulmonary tree is dissected extensively within the mediastinum, and the main pulmonary artery is divided. (c) The main pulmonary trunk is oversewn, and retraction sutures are placed to maintain orientation of the distal main pulmonary artery orifice. (d) The branch pulmonary arteries are divided along their natural raphe, and the preplaced retraction sutures are utilized to mobilize each branch extensively.
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Figure 1 Continued
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Figure 1 Continued
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Figure 1 Continued
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Figure 2 Extensive mobilization and dissection of the pulmonary tree is facilitated in an extrapericardial fashion if necessary. The right pulmonary artery can be mobilized lateral to the superior vena cava to improve visualization. Progressive increased retraction on both branch pulmonary arteries allows access to the lobar, segmental, and subsegmental levels, and surrounding pulmonary veins and airways.
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Figure 3 (a) The anterolateral aspect of the branch pulmonary artery gives rise to lobar vessels, with areas of stenosis and/or hypoplasia. (b) The posteromedial surface of the branch pulmonary artery can be opened longitudinally to allow intraluminal visualization of the opposing branches.
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Figure 4 (a) Proximal and distal branches can demonstrate both focal stenoses and long-segment hypoplasia. (b) The vector of branch arteries relative to the ongoing pulmonary artery helps to determine the appropriate reconstructive strategy. Acute take-offs and focal stenoses are more amenable to “v-plasty” (Fig. 5), while obtuse take-offs and long-segment hypoplasia is better served by pulmonary artery homograft patch augmentation (Fig. 6).
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Figure 5 (a) Longitudinal arteriotomy along the posteromedial surface of the pulmonary artery enables intraluminal access to branch points. (b) An ostial stenosis is located. (c) Retraction sutures are placed on either side of the planned “v-plasty.” (d) A planned incision line in the ongoing pulmonary artery is visualized, such that distortion of the smaller branch is minimized. (e) Counter-incisions are made in the ongoing pulmonary artery and in the branch to be augmented. These are extended an equal distance along both vessels, past the point of narrowing within the branch. (f) A fine (8-0) Prolene suture is placed through the distal end of both incisions. (g) Each end of the Prolene is then run in continuous fashion to bring the counter-incisions together in longitudinal fashion. These ends are carefully tied to themselves intraluminally, and the knots cut precisely to avoid excise suture material within the enlarged ostium. (h) The retraction sutures are removed. The ostial stenosis is eliminated, and the functional orifice to the branch is thus enlarged.
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Figure 6 Longitudinal pulmonary artery homograft patch augmentation is performed along the posteromedial arteriotomy to finish each branch pulmonary artery reconstruction. Obtuse take-off branches and long-segment hypoplasia can also be addressed in this fashion. At completion, all areas of stenosis and/or hypoplasia, through to the segmental and subsegmental levels, are improved and/or eliminated. Native-native tissue remains throughout the reconstruction, to ensure ongoing growth potential. The typical branch pulmonary artery reconstruction is depicted, although additional homograft patches may be utilized in select situations.
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Figure 7 Both augmented branch pulmonary arteries are returned to orthotopic position. The initial retraction sutures guide orientation and reconstruction of the original distal main pulmonary artery orifice, with the homograft augmentation returned to a posterior position (not visible). The distal and proximal main pulmonary arteries are reconnected, and the patient weaned from cardiopulmonary bypass (not depicted).
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Figure 8 Cather-based angiography remains the gold standard method for surgical planning to delineate areas of hypoplasia and/or branch stenosis. (a) Pre- and (b) postsurgical images from 1 such patient provide a sense for the degree of reconstruction afforded by this technique, although a complete understanding of each case requires several selective injections into individual lobar/segmental vessels to assess their overall distal pressures and character.
Complex Pulmonary Artery Reconstruction
Discussion Prior to this approach, PPAS and its related phenotypes were managed primarily through catheter-based interventions, with surgery (ie, hilum-hilum branch PA patch augmentation) limited to the intrapericardial branch PAs. Unfortunately, balloon angioplasty often resulted in only modest and transient improvements in right ventricular afterload. Stents seemed to offer a greater duration of short-term gain, at the expense of (1) eventual in-stent restenosis, (2) multibranch loss in the setting of stent obstruction at points of bifurcation, (3) loss of PA growth potential, and (4) mass effect compression to surrounding pulmonary veins and bronchioles. Several single-center series have examined outcomes of this approach,2-4 the largest of which included 69 patients treated over a 25-year period.2 In this cohort, the average right to left ventricular (RV:LV) pressure ratio improved from 1.0 (0.52-2.17) to 0.52 (0.24-1.04) after all interventions, with freedom from death or surgery 38% § 6% at 1 year and 22% § 6% at 5 years. Ten patients ultimately died and 13 required surgical intervention. PAR, which has been employed at our center as first-line therapy for these patients, avoids many of the catheter-based procedural shortcomings listed above, and attempts to provide a definitive and durable repair. The most recent published analysis5 of our cohort included 38 patients who had been treated in this manner, from 2002 to 2016. Underlying syndromes included Williams (n = 20), Alagille (n = 12), other (n = 3), and none (n = 3). Initial RV:LV pressure ratio improved from 0.94 (0.72-1.30) to 0.36 (0.19-0.54) after surgery. One operative mortality occurred in a Williams patient, in the setting of significant left ventricular dysfunction as a sequela of ongoing left-sided obstruction. One patient required Extra Corporeal Membrane Oxygenation for 4 postoperative days in the
175 setting of acute lung injury. At most recent follow-up (4 § 3 years), no long-term mortality has been observed. One patient has required balloon angioplasty of a focal recurrent PA stenosis. RV:LV pressure ratio remains stable at 0.35 § 0.04. We believe that ongoing follow-up for this surgical cohort, which has expanded to over 70 patients, will further validate complex PAR as a mainstay therapy for patients afflicted with PPAS and its related phenotypes. We hope that the outlined principles and stepwise illustrations depicted herein will allow for widespread adoption of PAR to improve outcomes for this critically-ill population of patients.
Acknowledgments The authors thank Michael Leonard, CMI, FAMI, American River College, Sacramento, CA, for preparing the illustrations for this publication.
References 1. Bauser-Heaton H, Borquez A, Han B, et al: Programmatic approach to management of tetralogy of Fallot with major aortopulmonary collateral arteries: A 15-year experience with 458 patients. Circ Cardiovasc Interv 10, 2017:e004952 2. Cunningham JW, McElhinney DB, Gauvreau K, et al: Outcomes after primary transcatheter therapy in infants and young children with severe bilateral peripheral pulmonary artery stenosis. Circ Cardiovasc Interv 6:460–467, 2013 3. Gandy KL, Tweddell JS, Pelech AN: How we approach peripheral pulmonary artey stenosis in Williams-Beuren Syndrome. Semin Thorac Cardiovasc Surg Pediatr Card Surg Ann 12:118–121, 2009 4. Stamm C, Friehs I, Moran A, et al: Surgery for bilateral outflow tract obstruction in elastin arteriopathy. J Thorac Cardiovasc Surg 120: 755–763, 2000 5. Mainwaring RD, Hanley FL: Surgical technique for repair of peripheral pulmonary artery stenosis. Semin Thoracic Surg 28:418–424, 2016