Operative Strategies for Pulmonary Artery Occlusion Secondary to Mediastinal Fibrosis

Operative Strategies for Pulmonary Artery Occlusion Secondary to Mediastinal Fibrosis Morgan L. Brown, MD, Alex R. Cedeño, BS, Eric S. Edell, MD, Donald J. Hagler, MD, and Hartzell V. Schaff, MD

Background. Fibrosing mediastinitis is a rare disease characterized by an excessive fibrotic reaction in the mediastinum, which may entrap mediastinal structures including the pulmonary arteries. Our objectives were to assess the surgical strategies and outcomes of repair of pulmonary artery occlusion attributable to mediastinal fibrosis. Methods. With approval from the Mayo Clinic Institutional Review Board, we identified all patients with fibrosing mediastinitis who underwent an operation for relief of pulmonary artery obstruction between 1980 and 2008. Perioperative data were collected using medical records and late follow-up surveys. Results. Operative procedures to bypass or reconstruct an obstructed pulmonary artery were performed in 5 patients. Patients’ median age was 40 years (range, 27 to 51 years), and all patients were symptomatic and had right ventricular hypertension. In 3 patients, a doubleoutlet right ventricle was constructed using a valved conduit (porcine valved conduit, n ⴝ 1; aortic homograft, n ⴝ 2) from the right ventricle to the right pulmonary artery. Two patients required complete reconstruction of the pulmonary artery confluence using a pulmonary

homograft in 1 patient and a hybrid technique of autologous pericardial reconstruction and intraoperative stenting in another patient. All patients had a reduction in right ventricular pressures after operation. One patient died perioperatively owing to respiratory failure; the remaining 4 patients were alive at a median follow-up of 7.4 years (range, 0.5 to 14.7 years). One patient required late balloon dilatation of the conduit and distal pulmonary arteries 10 years after initial operation, but the remaining conduits were widely patent at late follow-up. Late functional improvement was limited owing to other complications from mediastinal fibrosis or other comorbidities. Conclusions. Treatment of pulmonary artery occlusion attributable to mediastinal fibrosis can be challenging. Successful operative strategies include both creation of a double-outlet right ventricle and complete reconstruction of the pulmonary artery confluence. Hybrid techniques of both conduit placement and stenting should also be considered for patients with occluded pulmonary arteries. (Ann Thorac Surg 2009;88:233–7) © 2009 by The Society of Thoracic Surgeons

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fungal agents [9 –13]. Idiopathic mediastinal fibrosis may respond more favorably to corticosteroids than that caused by histoplasmosis [9 –12]. Surgery has been used to improve symptoms caused by vascular and airway obstruction, but success has been variable. The majority of reports are limited to interventions on systemic venous obstruction, and there are few publications on treatment of pulmonary artery (PA) obstruction. In this report we review the surgical methods used to manage PA obstruction in 5 patients with fibrosing mediastinitis.

ibrosing mediastinitis, also known as sclerosing mediastinitis or mediastinal fibrosis, is a rare disease characterized by an excessive fibrotic reaction in the mediastinum [1]. This may cause gradual obstruction of the airways, great vessels, and other mediastinal structures. Mediastinal fibrosis is thought to result from a delayed hypersensitivity reaction to a fungal, mycobacterial, bacterial, or other unknown antigen [1–5]. Prior infection with histoplasmosis is thought to be the most common infectious cause, but other precipitating antigens have been identified including tuberculosis and blastomycosis [6 – 8]. As well, there is a form of idiopathic fibrosing mediastinitis that may be related to an autoimmune disorder [2]. There is no uniformly effective medical therapy to treat fibrosing mediastinitis, although there have been several reports of the use of corticosteroids and anti-

Accepted for publication April 3, 2009. Address correspondence to Dr Brown, Mayo Clinic, 200 1st Ave SW, Rochester, MN 55905; e-mail: [email protected].

© 2009 by The Society of Thoracic Surgeons Published by Elsevier Inc

Material and Methods After approval from the Mayo Clinic Institutional Review Board, we identified all patients with fibrosing mediastinitis who had involvement of the PA and underwent an operative intervention to bypass or reconstruct the PAs between 1980 and 2007. Perioperative data were collected using all medical records. Survival status was ascertained through Accurint (Lexus Nexus) and follow-up survey information. 0003-4975/09/$36.00 doi:10.1016/j.athoracsur.2009.04.012

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Divisions of Cardiovascular Surgery, Pulmonary and Critical Care Medicine, and Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota; and School of Medicine, University of Puerto Rico, San Juan, Puerto Rico

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Fig 1. Computed tomography demonstrating an obstructed right pulmonary artery (arrow) secondary to mediastinal fibrosis.

Results Operative procedures to bypass or reconstruct the obstructed PA were performed in 5 patients (Fig 1). All patients were severely symptomatic with exertional dyspnea, and 4 of 5 had severe right ventricular hypertension with median preoperative right ventricular systolic pressure of 70 mm Hg (range, 33 to 110 mm Hg) on echocardiography. Anatomic findings that prompted consideration of surgery included severely narrowed or occluded PAs, an adequately sized PA at the anticipated site of distal anastomoses, and adequate distal perfusion and ventilation (Table 1). In 3 patients, a double-outlet right ventricle was created to bypass an obstructed PA (Table 2). All patients underwent midline sternotomy, and cardiopulmonary bypass at 2.4 L · min⫺1 · m⫺2 was used. Patient 1 was cooled to 18°C for circulatory arrest, during which time the superior vena cava was divided and a pulmonary arteriotomy was made along the right PA (RPA); a 22-mm Hancock valve (Hancock-Extracorporeal Inc, Anaheim, CA) conduit was sewn to the RPA. Connection of the superior vena cava to the right atrium was established using a 15-mm Gore-Tex graft. Perfusion was recommenced, and the patient was rewarmed. The PA conduit was beveled and sewn to the right ventricle using an oblique right ventriculotomy. In patients 2 and 3, a longitudinal incision was performed in the RPA. Thrombi

were removed from the lumen, and the arteriotomy was extended beneath the superior vena cava until reasonable backbleeding was achieved and no residual obstruction could be ascertained. Pulmonary artery to right ventricle connection was reestablished in both patients by means of a 22-mm aortic homograft sewn proximally to a right ventriculotomy. In patient 2, to prevent distortion of the homograft conduit, a proximal extension of a Hemashield Dacron graft (24 mm) was beveled and sewn to the right ventriculotomy; then, it was trimmed to the appropriate length and sewn to the proximal portion of the homograft (Fig 2). In patient 3, the superior vena cava was widely mobilized so that it would not compress the distal anastomosis. Both operations (patients 2 and 3) were done with the heart beating. In 2 patients, the pulmonary arteries were encased in an inflammatory mass of lymph nodes and complete reconstruction of the PA confluence was required. Patient 4 was cooled to 20°C, and a period of low flow (0.5 L · min⫺1 · m⫺2) was used to facilitate exposure during the anastomoses. The RPA was opened longitudinally posterior to the aorta, and the thrombus filling the posterior aspect of the artery was removed. Good backbleeding was evident, but there was a large hole in the posterior RPA where a lymph node had eroded into the wall. This section of the PA was excised and a 26-mm pulmonary homograft was sewn to the left PA at the pericardial reflection and to the RPA posterior to the superior vena cava. The homograft was then sewn to the native central PA. In patient 5, cardiopulmonary bypass was initiated, but normothermia was maintained while the PAs were examined. No segment of the PAs was palpable that was either proximal enough or large enough to consider bypass. Therefore, a longitudinal arteriotomy was made on the main PA and extended on to the left PA until backbleeding was evident from the distal artery. The necrotic lymph nodes that were eroding into the back wall of the left PA were excised, and an autologous piece of pericardium was harvested. A pericardial patch was sewn to the pulmonary arteriotomy to create a patch angioplasty. In conjunction with an interventional cardiologist, a stent was inserted into both the left PA and RPA under direct vision. The expanded stents were tacked to the pulmonary wall, and then the remaining pericardial patch was used to close the incision in the PA. Of note, this patient had previous assessments by

Table 1. Patient Preoperative Characteristics Patient Age at Histoplasmosis No. Operation (y) Sex Serology 1 2 3 4 5 a

51 42 40 31 27

F F F M F

Unknown Negative Negative Negative Positive

Mediastinal Structures Involved Occlusion Occlusion Occlusion Occlusion Occlusion

LPA, stenosis RPA, occlusion L mainstem bronchus RPA RPA RPA, stenosis LPA LPA, stenosis RPA

Measured directly at time of operation, under anesthesia.

L ⫽ left;

LPA ⫽ left pulmonary artery;

RPA ⫽ right pulmonary artery.

Right Ventricular Pressures (mm Hg)a 70/10 46/3 28/0 64/4 35/10

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Patient No.

Operative Approach

Year of Operation

Cardiopulmonary Bypass Time (min)

Circulatory Arrest Time (min)

Conduit or Reconstruction Material

1 2

Double-outlet right ventricle Double-outlet right ventricle

1990 1999

153 82

53 0

3 4

Double-outlet right ventricle Reconstruction of central pulmonary arteries Reconstruction of central pulmonary arteries

2000 1992

64 132

0 0

2007

74

0

22-mm Hancock 22-mm aortic homograft and 26-mm Gore-Tex 22-mm aortic homograft 26-mm pulmonary homograft Pericardium and 2 Palmaz P308 stents

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interventional radiologists who did not think that the PAs could be stented. In all 5 patients, a reduction in right ventricular systolic pressures was noted after conduit placement. The median postoperative right ventricular systolic pressure was 29 mm Hg (range, 23 to 56 mm Hg). Patients were not anticoagulated postoperatively. One patient (patient 1) died perioperatively as a result of respiratory failure and cardiac arrest after endoscopy for investigation of dysphagia. The remaining 4 patients were alive at a median follow-up of 7.4 years (range, 0.5 to 14.7 years). Patient 4 required balloon angioplasty of the conduit and stenting of distal PAs almost 10 years after the initial bypass procedure (Fig 3), but other conduits remain patent and free of reintervention (Fig 4). Patients rated their overall activity levels compared with their peers at between 2 and 4 on a scale of 1 to 10 (10 being the highest rating) at follow-up. Poor functional status and quality of life was associated with other complications owing to mediastinal fibrosis or other comorbidities such as depression or severe chronic obstructive pulmonary disease.

Comment Fibrosing mediastinitis is a rare disorder. Histoplasmosis is the most common precipitating factor in the United

Sates, but other antigens have also been implicated [1– 8]. In addition, there is a rare subtype called idiopathic mediastinal fibrosis, which may be related to an underlying autoimmune condition [2]. In the case of histoplasmosis, as the acute infection heals, caseation develops in mediastinal lymph nodes, generally located adjacent to mainstem bronchi. These granulomas may rupture, spreading caseous material into the mediastinum where an intense inflammatory reaction occurs. As the inflammation heals, collagen is produced, which may entrap mediastinal structures [1–5]. Stenosis or obstruction of the venae cavae, pulmonary veins, bronchi, and the PAs all produce distinctive clinical pictures and may be observed alone or in combination. Of these structures, involvement of the PA is quite rare [14, 15]. Pulmonary artery obstruction may lead to right ventricular hypertension with resultant right heart dysfunction, shortness of breath, and fatigue. There is no universally successful treatment for fibrosing mediastinitis. Medications, such as corticosteroids and antifungal agents, are generally thought to be ineffective in these patients; however, there may be some role for corticosteroids in patients with the rare idiopathic mediastinal fibrosis [9, 10, 12]. Both stents and surgery have been performed to relieve vascular and airway obstruction, but there are few data on long-term results in the literature. Extensive fibrosis, calcification, Fig 2. This figure demonstrates the placement of an aortic homograft from the right ventricle to the right pulmonary artery (RPA). (A) A longitudinal incision is made in the right ventricle and the superior vena cava is retracted medially to expose the right pulmonary artery where a longitudinal pulmonary arteriotomy was made. (B) An aortic homograft may be used because it is more pliable and has a slight curve that allows for a more natural position when in place. A small piece of Dacron graft was used as a proximal extension from the right ventricle to the aortic homograft. In patients with mediastinal fibrosis, the right ventricle is generally not grossly enlarged or hypertrophied, which allows for easier conduit placement between the right ventricle and sternum.

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Table 2. Operative Characteristics

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Fig 3. Contrast angiography demonstrating results before (A) and after (B) stenting of the right pulmonary artery and placement of a homograft conduit 10 years after operation.

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and collateral vessels limit the surgical options for direct repair, and these complicating features are the main causes of surgical morbidity and mortality. Obstruction of the bronchi can be difficult to treat, especially if dilation is not possible owing to extensive fibrosis. Early excision of granulomas has been advised in an effort prevent disease progression and proximal bronchial involvement [16]. In the series by Mathisen and Grillo [16], 3 of 4 deaths occurred in patients who required carinal pneumonectomy. Superior vena cava obstruction has been a frequently reported complication. Endovascular stenting is now the first option for treatment although late outcomes are not known [17, 18]. When operation is necessary, spiral vein grafts or externally reinforced polytetrafluoroethylene grafts can be used to bypass the involved segment [19 –21]. The pulmonary veins are also frequently amenable to stenting, and this procedure may be preferred as outcomes from operation on the pulmonary veins in other conditions are variable [22]. The successful experience with conduit reconstruction of right ventricular outflow obstruction in congenital

Fig 4. A homograft conduit is visible connecting the right ventricle and right pulmonary artery (arrows). Eight years after operation, the conduit was patent with a normally functioning valve and calcium in the wall of the homograft.

heart disease has led us to attempt restoration of antegrade lung perfusion by bypassing the PA obstruction with valved conduits that originate on the right ventricle. This approach minimizes mobilization of rock-hard tissues in the central mediastinum, and proximal anastomosis of the conduit to the right ventricle can be performed easily with the heart beating on cardiopulmonary bypass. We have used both homografts and porcinevalved Dacron grafts. Homografts may have some advantages as regards ease of handling and suturing to thinwalled PAs. Restoration of pulmonary blood flow has been successful in each of the 3 patients in whom this approach used, no aortic cross-clamping was needed, and the procedure has been well tolerated. A hypothetical long-term risk is persistence of histoplasmosis and fibrous proliferation that can progress and cause obstruction of the bypass conduits. Thus, adequate follow-up with imaging techniques is imperative. In our limited experience, graft patency is excellent in the midterm. It is possible to that calcification of the valve within the conduit may eventually lead to conduit failure. Echocardiography and computed tomography or magnetic resonance imaging were performed in all patients before operation, but cardiac catheterization or exercise functional testing may be required in select patients. Follow-up should be based on patient symptom status. Imaging is directed at visualization of the conduit through either computed tomography or transesophageal echocardiography. There are also several case reports of stenting the PAs for mediastinal fibrosis [23–30]. These also appear to have good early results in properly selected patients, but should be performed by interventional cardiologists experienced in the stenting of venous structures [24]. We used stents at the time of operation in 1 patient (patient 5) and another patient required late angioplasty and stenting of the homograft conduit and distal left and right PAs (patient #4). A hybrid approach consisting of concomitant or delayed operation and stenting can be considered as a potential strategy in these difficult patients. Treatment of PA occlusion attributable to mediastinal fibrosis can be challenging. Operative approaches include both creation of a double-outlet right ventricle

using a conduit or complete reconstruction of the PA confluence. These may be performed safely in selected symptomatic patients who have appropriate PA anatomy. Although the surgical treatment was technically successful in all patients in our series, late functional outcomes are affected by other mediastinal structure involvement and patient comorbidities. Hybrid techniques of both conduit placement and stenting should be considered for patients with severely obstructive PAs. This project was made possible by Grant Number 1 TL1 RR024152 from the National Center for Research Resources (NCRR), a component of the National Institutes of Health (NIH), and the NIH Roadmap for Medical Research.

References 1. Fibrosing Mediastinitis. Available at: http://www. uptodate.com/online/content/topic.do?topicKey⫽int_pulm/ 6609&selectedTitle⫽1⬃12&source⫽search_result. Accessed December 1, 2008. 2. Mole TM, Glover J, Sheppard MN. Sclerosing mediastinitis: a report on 18 cases. Thorax 1995;50:280 –3. 3. Goodwin RA, Nickell JA, des Prez RM. Mediastinal fibrosis complicating healed primary histoplasmosis and tuberculosis. Medicine 1972;51:227– 46. 4. Dines DE, Spencer PW, Bernatz PE, Pairolero PC. Mediastinal granuloma and fibrosing mediastinitis. Chest 1979;75: 320 – 4. 5. Loyd JE, Tillman BF, Atkinson JB, des Prez RM. Mediastinal fibrosis complicating histoplasmosis. Medicine (Baltimore) 1988;67:295–310. 6. Zhang C, Yao M, Yu Z, Jiang L, Jiang X, Ni Y. Rare fibrosing granulomatous mediastinitis of tuberculosis with involvement of the transverse sinus. J Thorac Cardiovasc Surg 2007:133:836 –7. 7. Esquivel L, Diaz-Picado H. Fibrosing TB mediastinitis presenting as a superior vena cava syndrome: a case presentation and echocardiogram correlate. Echocardiography 2006; 23:588 –91. 8. Lagerstrom CF, Mitchell HG, Graham BS, Hammon JW Jr. Chronic fibrosing mediastinitis and superior vena caval obstruction from blastomycosis. Ann Thorac Surg 1992;54: 764 –5. 9. Ikeda K, Nomori H, Mori T, et al. Successful steroid treatment for fibrosing mediastinitis and sclerosing cervicitis. Ann Thorac Surg 2007;83:1199 –201. 10. Ichimura H, Ishikawa S, Yamamoto T, et al. Effectiveness of steroid treatment for hoarseness caused by idiopathic fibrosing mediastinitis: report of a case. Surg Today 2006;36: 382– 4. 11. Urschel HC, Razzuk MA, Netto GJ, Disiere J, Chung SY. Sclerosing mediastinitis: improved management with histoplasmosis titer and ketoconazole. Ann Thorac Surg 1990; 50:215–21. 12. Lal C, Weiman D, Eltorky M, Pugazhenthi M. Complete resolution of fibrosing mediastinitis with corticosteroid therapy. South Med J 2007;987:749 –50.

BROWN ET AL OPERATIVE TREATMENT IN MEDIASTINAL FIBROSIS

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13. Worrell JA, Donnelly EF, Martin JB, Bastarache JA, Loyd JE. Computed tomography and the idiopathic form of proliferative fibrosing mediastinitis. J Thorac Imaging 2007;22: 235– 40. 14. Berry DF, Buccigrossi D, Peabody J, Peterson KL, Moser KM. Pulmonary vascular occlusion and fibrosing mediastinitis. Chest 198;89:291–301. 15. Wieder S, White TJ, Salazar J, Gold RE, Moinuddin M, Tonkin I. Pulmonary artery occlusion due to histoplasmosis. AJR Am J Roentgenol 1982;138:243–51. 16. Mathisen D, Grillo HC. Clinical manifestation of mediastinal fibrosis and histoplasmosis. Ann Thorac Surg 1992;54: 1053– 8. 17. Rizvi AZ, Kalra M, Bjarnason H, Bower TC, Schleck C, Gloviczki P. Benign superior vena cava syndrome: stenting is now the first line of treatment. J Vasc Surg 2008;47:372– 80. 18. Eguchi K, Kobayashi K, Hasegawa I, Nakatsuka S. Restenosis of superior vena cava after treatment using a selfexpanding metallic stent in a patient with idiopathic fibrosing mediastinitis. Interact Cardiovasc Thorac Surg 2003;2: 355–7. 19. Pompeo E, Stella F, Ippoliti A, Mineo T. Extra-anatomic bypass of the superior vena cava after successful stenting for fibrosing mediastinitis. J Thorac Cardiovasc Surg 2008;135: 220 –1. 20. Doty JR, Flores JH, Doty DB. Superior vena cava obstruction: bypass using spiral vein graft. Ann Thorac Surg 1999;67: 1111– 6. 21. Levitt RG, Glazer HS, Gutierrez F, Moran J. Magnetic resonance imaging of spiral vein bypass of superior vena cava in fibrosing mediastinitis. Chest 1986;90:676 – 80. 22. van Son JA, Danielson GK, Puga FJ, Edwards WD, Driscoll DJ. Repair of congenital and acquired pulmonary vein stenosis. Ann Thorac Surg 1995;60:144 –50. 23. Satpathy R, Aguila V, Mohiuddin SM, Khan IA. Fibrosing mediastinitis presenting as pulmonary stenosis: stenting works. Int J Cardiol 2007;118:e85– 6. 24. Doyle TP, Loyd JE, Robbins IM. Percutaneous pulmonary artery and vein stenting: a novel treatment for mediastinal fibrosis. Am J Respir Crit Care Med 2001;164:657– 60. 25. Hamilton-Craig CR, Slaughter R, McNeil K, Kermeen F, Walters DL. Improvements after angioplasty and stenting of pulmonary arteries due to sarcoid mediastinal fibrosis: case report. Heart Lung Circ 2008 Mar 28;epub. 26. Guerrero A, Hoffer EK, Hudson L, Schuler P, Karmy-Jones R. Treatment of pulmonary artery compression due to fibrous mediastinitis with endovascular stent placement. Chest 2001;119:966 – 8. 27. Thiessen R, Matzinger FR, Seely J, Aina R, Macleod P. Fibrosing mediastinitis: successful stenting of the pulmonary artery. Can Respir J 2008;15:41– 4. 28. Kandzari DE, Warner JJ, O’Laughlin MP, Harrison KJ. Percutaneous stenting of right pulmonary artery stenosis in fibrosing mediastinitis. Cardiovasc Intervent 2000;49:321– 4. 29. Fontaine AB, Borsa JJ, Hoffer EK, Bloch RD, So C. Stent placement in the treatment of pulmonary artery stenosis secondary to fibrosing mediastinitis. J Vasc Interv Radiol 1002;12:1107–11. 30. Guerrero A, Hoffer EK, Hudson L, Schuler P, Karmy-Jones R. Treatment of pulmonary artery compression due to fibrous mediastinitis with endovascular stent placement. Chest 2001;119:966 – 8.

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