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Saphenous vein graft pseudoaneurysm formation after postoperative mediastinitis
Saphenous Vein Graft Pseudoaneurysm Formation After Postoperative Mediastinitis Julian A. Smith, FRACS, and Jacob Goldstein, FRACS Cardiothoracic Surgery Unit, Alfred Hospital, Prahran, Victoria, Australia
Pseudoaneurysm formation involving the body of an aortocoronary saphenous vein graft is a rare event. True aneurysmal dilatation of the graft and anastomotic pseudoaneurysm formation occur more commonly. We present the case of a 73-year-old woman in whom a pseudoaneurysm communicating with the body of a
P
ostoperative mediastinal infection is a serious complication of myocardial revascularization. A potentially lethal sequel of mediastinal sepsis is pseudoaneurysm formation. This may occur at a variety of positions including anastomoses and cannulation sites, but very rarely within the body of a saphenous vein graft alone. We report the case of pseudoaneurysm formation involving an aortocoronary saphenous vein graft, presumably after an episode of mediastinal sepsis. A 73-year-old non-insulin-dependent diabetic woman with postinfarction angina pectoris due to triple-vessel coronary disease underwent coronary artery bypass grafting in early April 1991. Her left internal mammary artery was applied to the left anterior descending coronary artery, and separate reversed saphenous vein grafts were applied to the obtuse marginal and posterior descending coronary arteries. Her initial postoperative course was uncomplicated until she presented in early May 1991 with a septicemic illness due to Staphylococcus aureus and renal failure. A small hemoserous discharge was noted from the lower end of her sternal wound. The wound was not tender and the bone edges were firmly united. The lower end of her wound was explored and no evidence of deep-seated infection was found. She was treated with intravenous antibiotics, rehydration, and dopamine for her renal failure and made a satisfactory recovery. In the middle of June 1991 she was seen again with an enlarging, pulsatile mass over the xiphoid region. A lateral chest roentgenogram (Fig 1) revealed her lower figure-of-8 sternal wire was displaced anteriorly from the body of the sternum. Needle aspiration of the mass revealed bloody fluid from which Staphylococcus aureus was grown. Echocardiography confirmed the presence of a cavity that communicated with the circulation. She underwent an emergency operation with cardioAccepted for publication Jan 9, 1992. Address reprint requests to Dr Goldstein, Cabrini Medical Center, Private Consulting Rooms, Isabella Street, Malvem, 3144 Victoria, Australia.
0 1992 by The Society of Thoracic Surgeons
posterior descending coronary artery saphenous vein graft developed, presumably after a postoperative sternal wound infection. The aneurysm was excised and the defect within the saphenous vein graft repaired using hypothermia and circulatory arrest. (Ann Thorac Surg 1992;54:766-8)
pulmonary bypass being established through an arterial cannula in the femoral artery and venous cannulas within the femoral and internal jugular veins. After cooling to 18"C, during which ventricular fibrillation occurred, the circulation was turned off and the mass entered. A bilobar aneurysm cavity containing blood was found (Fig 2). The superficial portion was approximately 8 x 5 cm in size with its neck at the level of the sternum, which had been eroded above the xiphoid. The lower, slightly smaller portion lay below sternal level, but above the heart. There was a bleeding vessel within the deepest portion, which represented erosion of the saphenous vein graft feeding the posterior descending coronary artery. The lowest (most inferior) sternal wire lay almost free within the anterior cavity but was still attached to a remnant of sternum at one point. Surrounding the cavity, but slightly superiorly, around the middle sternal wire was a collection of purulent material which drained from around this wire and multiple lateral sinuses within the soft tissues of the chest wall. There was much necrotic tissue surrounding both the aneurysm cavity and the purulent material, with the skin over the point of the aneurysm cavity breaking down. The upper half of the sternum was intact, with no evidence of infection. The wall of the aneurysm cavity was removed and the bleeding saphenous vein graft in the base of the cavity was oversewn with 5-0 Prolene (Ethicon, Somerville, NJ) suture. All necrotic and purulent material was debrided and sections of sternum and costal cartilages were excised to leave freely bleeding surfaces. The patient was rewarmed, spontaneously defibrillated, and weaned from cardiopulmonary bypass with ease. The resultant sternal cavity was dressed with povidone-iodine (Betadine; Faulding Pharmaceuticals, South Australia)-soaked gauze. After the use of regular dressings and systemic antibiotics to eradicate local sepsis, the sternal defect was repaired by rotating a right pectoralis major muscle flap. However, the resultant wound broke down and she required the transfer of omentum and a split skin graft to close the defect. She was discharged home well in the 0003-4975/92/$5.00
CASE REPORT
Ann Thorac Surg 1992;54:76&3
SMITH AND GOLDSTEIN GRAFT PSEUDOANEURYSM
767
Fig 3. Completed chest wall reconstruction after filling the defect with omentum and laying on a split skin graft.
Fig 1 . Lateral chest roentgenogram showing the anteriorly displaced inferior sternal wire.
middle of August 1991. The final reconstructive result is shown in Figure 3.
Comment The most common form of aneurysms seen in saphenous vein aortocoronary grafts are the true atherosclerotic
\
n
STERNAL WIRE WITH ANEURYSM
XIPHI-- STERNUM Fig 2. Midsagittal section diagram showing the operative findings (see text).
variety [l,21. Their incidence increases with time and they are often filled with thrombus, thus contributing to late graft stenosis and occlusion. False or pseudoaneurysm formation is rare and may occur at proximal [3] or distal [4] anastomotic sites. Mediastinal sepsis, especially due to Staphylococcus uureus, is the major predisposing factor in more than half of the cases [3]. Mycotic or infected pseudoaneurysms result from direct extension or hematogenous seeding to the anastomotic site leading to suture line dehiscence. Involvement of the body of the graft in this process is unusual, but mycotic aneurysm formation at this location has been reported to coexist with an anastomotic pseudoaneurysm [ 5 ] . Presumably the body of the graft or a branch ligature is directly invaded. It is clear that our patient had deep-seated mediastinal sepsis that was not apparent at her original presentation. The diagnosis of these aneurysms may be difficult [3]. The symptoms may include fever, chest pain, evidence of myocardial ischemia, local compressive features, or rupture [3, 61. We were aided by the extension of the process to the surface. Echocardiography was an ideal noninvasive means of confirming the diagnosis. Other investigations that have been employed include contrast-enhanced computed tomography, magnetic resonance imaging, and angiography [3, 71. As the risk of rupture is high, expeditious surgical repair is required, although successful transcatheter embolization has been reported [8].We, along with others [3, 9, 101, recommend the use of cardiopulmonary bypass, deep hypothermia, and a brief period of circulatory arrest to achieve a safe re-entry, aneurysm excision, and repair. It was impossible to primarily close the wound in our patient, and therefore subsequent soft tissue reconstruction was required. A long course of appropriate antibiotics is mandatory in these patients. We have presented a rare sequel to the complication of mediastinal sepsis after coronary artery bypass grafting. The involvement of the body of the saphenous vein graft and the subsequent presentation were most unusual. A successful outcome was achieved by using a stepwise management plan.
768
Ann Thorac Surg 1992;54:7664
CASE REPORT SMITH AND GOLDSTEIN GRAFT PSEUDOANEURYSM
We acknowledge the assistance of Richard Maxwell, FRACS, and Roaer Wale, FRACS, in managine; this patient. 6.
References 1. Neitzel GF, Barboriak JJ, Pintar K, Qureshi I. Atherosclerosis in aortocoronary bypass grafts. Morphological study and risk factor analysis 6 to 12 years after surgery. Arteriosclerosis 1986;6594400. 2. Pintar K, Barboriak JJ, Johnson WD, Co ED. Atherosclerotic aneurysm in aortocoronary vein graft. Arch Pathol Lab Med 1978;102:287-8. 3. Sullivan KL, Steiner RM, Smullens SN, Griska L, Meister SG. Pseudoaneurysm of the ascending aorta following cardiac surgery. Chest 1988;93:13%43. 4. De Haan HPJ, Huysmans HA, Weeda HWH, Bosker HA, Buis B. Anastomotic pseudoaneurysm after aorto-coronary bypass grafting. Thorac Cardiovasc Surg 1985;33:554. 5. Douglas BP, Bulkley BH, Hutchins GM. Infected saphenous
7. 8.
9.
10.
vein coronary artery bypass graft with mycotic aneurysm. Fatal dehiscence of the proximal anastomosis. Chest 1979;75: 76-7. Rosin MD, Ridley PD, Maxwell PH. Rupture of a pseudoaneurysm of a saphenous vein coronary arterial bypass graft presenting with superior caval venous obstruction. Int J Cardiol 1989;25:121-3. Sherry CS, Harms SE. MR imaging of pseudoaneurysms in aortocoronary bypass graft. J Comput Assist Tomogr 1989; 13:426-9. Kim D, Guthaner DF, Wexler L. Transcatheter embolization of a leaking pseudoaneurysm of saphenous vein aortocoronary bypass graft. Cathet Cardiovasc Diagn 1983;9:5914. Lillehei CW, Todd DB, Levy MJ, Ellis RJ. Partial cardiopulmonary bypass, hypothermia, and total circulatory arrest. A lifesaving technique for ruptured mycotic aortic aneurysms, ruptured left ventricle, and other complicated cardiac pathology. J Thorac Cardiovasc Surg 1969;58:530-44. Smith P, Qureshi S, Yacoub MH. Dehiscence of infected aortocoronary vein graft suture lines. Cause of late pseudoaneurysm of ascending aorta. Br Heart J 1983;50:19%5.
Pseudoaneurysm formation involving the body of an aortocoronary saphenous vein graft is a rare event. True aneurysmal dilatation of the graft and anastomotic pseudoaneurysm formation occur more commonly. We present the case of a 73-year-old woman in whom a pseudoaneurysm communicating with the body of a
P
ostoperative mediastinal infection is a serious complication of myocardial revascularization. A potentially lethal sequel of mediastinal sepsis is pseudoaneurysm formation. This may occur at a variety of positions including anastomoses and cannulation sites, but very rarely within the body of a saphenous vein graft alone. We report the case of pseudoaneurysm formation involving an aortocoronary saphenous vein graft, presumably after an episode of mediastinal sepsis. A 73-year-old non-insulin-dependent diabetic woman with postinfarction angina pectoris due to triple-vessel coronary disease underwent coronary artery bypass grafting in early April 1991. Her left internal mammary artery was applied to the left anterior descending coronary artery, and separate reversed saphenous vein grafts were applied to the obtuse marginal and posterior descending coronary arteries. Her initial postoperative course was uncomplicated until she presented in early May 1991 with a septicemic illness due to Staphylococcus aureus and renal failure. A small hemoserous discharge was noted from the lower end of her sternal wound. The wound was not tender and the bone edges were firmly united. The lower end of her wound was explored and no evidence of deep-seated infection was found. She was treated with intravenous antibiotics, rehydration, and dopamine for her renal failure and made a satisfactory recovery. In the middle of June 1991 she was seen again with an enlarging, pulsatile mass over the xiphoid region. A lateral chest roentgenogram (Fig 1) revealed her lower figure-of-8 sternal wire was displaced anteriorly from the body of the sternum. Needle aspiration of the mass revealed bloody fluid from which Staphylococcus aureus was grown. Echocardiography confirmed the presence of a cavity that communicated with the circulation. She underwent an emergency operation with cardioAccepted for publication Jan 9, 1992. Address reprint requests to Dr Goldstein, Cabrini Medical Center, Private Consulting Rooms, Isabella Street, Malvem, 3144 Victoria, Australia.
0 1992 by The Society of Thoracic Surgeons
posterior descending coronary artery saphenous vein graft developed, presumably after a postoperative sternal wound infection. The aneurysm was excised and the defect within the saphenous vein graft repaired using hypothermia and circulatory arrest. (Ann Thorac Surg 1992;54:766-8)
pulmonary bypass being established through an arterial cannula in the femoral artery and venous cannulas within the femoral and internal jugular veins. After cooling to 18"C, during which ventricular fibrillation occurred, the circulation was turned off and the mass entered. A bilobar aneurysm cavity containing blood was found (Fig 2). The superficial portion was approximately 8 x 5 cm in size with its neck at the level of the sternum, which had been eroded above the xiphoid. The lower, slightly smaller portion lay below sternal level, but above the heart. There was a bleeding vessel within the deepest portion, which represented erosion of the saphenous vein graft feeding the posterior descending coronary artery. The lowest (most inferior) sternal wire lay almost free within the anterior cavity but was still attached to a remnant of sternum at one point. Surrounding the cavity, but slightly superiorly, around the middle sternal wire was a collection of purulent material which drained from around this wire and multiple lateral sinuses within the soft tissues of the chest wall. There was much necrotic tissue surrounding both the aneurysm cavity and the purulent material, with the skin over the point of the aneurysm cavity breaking down. The upper half of the sternum was intact, with no evidence of infection. The wall of the aneurysm cavity was removed and the bleeding saphenous vein graft in the base of the cavity was oversewn with 5-0 Prolene (Ethicon, Somerville, NJ) suture. All necrotic and purulent material was debrided and sections of sternum and costal cartilages were excised to leave freely bleeding surfaces. The patient was rewarmed, spontaneously defibrillated, and weaned from cardiopulmonary bypass with ease. The resultant sternal cavity was dressed with povidone-iodine (Betadine; Faulding Pharmaceuticals, South Australia)-soaked gauze. After the use of regular dressings and systemic antibiotics to eradicate local sepsis, the sternal defect was repaired by rotating a right pectoralis major muscle flap. However, the resultant wound broke down and she required the transfer of omentum and a split skin graft to close the defect. She was discharged home well in the 0003-4975/92/$5.00
CASE REPORT
Ann Thorac Surg 1992;54:76&3
SMITH AND GOLDSTEIN GRAFT PSEUDOANEURYSM
767
Fig 3. Completed chest wall reconstruction after filling the defect with omentum and laying on a split skin graft.
Fig 1 . Lateral chest roentgenogram showing the anteriorly displaced inferior sternal wire.
middle of August 1991. The final reconstructive result is shown in Figure 3.
Comment The most common form of aneurysms seen in saphenous vein aortocoronary grafts are the true atherosclerotic
\
n
STERNAL WIRE WITH ANEURYSM
XIPHI-- STERNUM Fig 2. Midsagittal section diagram showing the operative findings (see text).
variety [l,21. Their incidence increases with time and they are often filled with thrombus, thus contributing to late graft stenosis and occlusion. False or pseudoaneurysm formation is rare and may occur at proximal [3] or distal [4] anastomotic sites. Mediastinal sepsis, especially due to Staphylococcus uureus, is the major predisposing factor in more than half of the cases [3]. Mycotic or infected pseudoaneurysms result from direct extension or hematogenous seeding to the anastomotic site leading to suture line dehiscence. Involvement of the body of the graft in this process is unusual, but mycotic aneurysm formation at this location has been reported to coexist with an anastomotic pseudoaneurysm [ 5 ] . Presumably the body of the graft or a branch ligature is directly invaded. It is clear that our patient had deep-seated mediastinal sepsis that was not apparent at her original presentation. The diagnosis of these aneurysms may be difficult [3]. The symptoms may include fever, chest pain, evidence of myocardial ischemia, local compressive features, or rupture [3, 61. We were aided by the extension of the process to the surface. Echocardiography was an ideal noninvasive means of confirming the diagnosis. Other investigations that have been employed include contrast-enhanced computed tomography, magnetic resonance imaging, and angiography [3, 71. As the risk of rupture is high, expeditious surgical repair is required, although successful transcatheter embolization has been reported [8].We, along with others [3, 9, 101, recommend the use of cardiopulmonary bypass, deep hypothermia, and a brief period of circulatory arrest to achieve a safe re-entry, aneurysm excision, and repair. It was impossible to primarily close the wound in our patient, and therefore subsequent soft tissue reconstruction was required. A long course of appropriate antibiotics is mandatory in these patients. We have presented a rare sequel to the complication of mediastinal sepsis after coronary artery bypass grafting. The involvement of the body of the saphenous vein graft and the subsequent presentation were most unusual. A successful outcome was achieved by using a stepwise management plan.
768
Ann Thorac Surg 1992;54:7664
CASE REPORT SMITH AND GOLDSTEIN GRAFT PSEUDOANEURYSM
We acknowledge the assistance of Richard Maxwell, FRACS, and Roaer Wale, FRACS, in managine; this patient. 6.
References 1. Neitzel GF, Barboriak JJ, Pintar K, Qureshi I. Atherosclerosis in aortocoronary bypass grafts. Morphological study and risk factor analysis 6 to 12 years after surgery. Arteriosclerosis 1986;6594400. 2. Pintar K, Barboriak JJ, Johnson WD, Co ED. Atherosclerotic aneurysm in aortocoronary vein graft. Arch Pathol Lab Med 1978;102:287-8. 3. Sullivan KL, Steiner RM, Smullens SN, Griska L, Meister SG. Pseudoaneurysm of the ascending aorta following cardiac surgery. Chest 1988;93:13%43. 4. De Haan HPJ, Huysmans HA, Weeda HWH, Bosker HA, Buis B. Anastomotic pseudoaneurysm after aorto-coronary bypass grafting. Thorac Cardiovasc Surg 1985;33:554. 5. Douglas BP, Bulkley BH, Hutchins GM. Infected saphenous
7. 8.
9.
10.
vein coronary artery bypass graft with mycotic aneurysm. Fatal dehiscence of the proximal anastomosis. Chest 1979;75: 76-7. Rosin MD, Ridley PD, Maxwell PH. Rupture of a pseudoaneurysm of a saphenous vein coronary arterial bypass graft presenting with superior caval venous obstruction. Int J Cardiol 1989;25:121-3. Sherry CS, Harms SE. MR imaging of pseudoaneurysms in aortocoronary bypass graft. J Comput Assist Tomogr 1989; 13:426-9. Kim D, Guthaner DF, Wexler L. Transcatheter embolization of a leaking pseudoaneurysm of saphenous vein aortocoronary bypass graft. Cathet Cardiovasc Diagn 1983;9:5914. Lillehei CW, Todd DB, Levy MJ, Ellis RJ. Partial cardiopulmonary bypass, hypothermia, and total circulatory arrest. A lifesaving technique for ruptured mycotic aortic aneurysms, ruptured left ventricle, and other complicated cardiac pathology. J Thorac Cardiovasc Surg 1969;58:530-44. Smith P, Qureshi S, Yacoub MH. Dehiscence of infected aortocoronary vein graft suture lines. Cause of late pseudoaneurysm of ascending aorta. Br Heart J 1983;50:19%5.