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Visceral and Limb Perfusion During Thoracoabdominal Aortic Aneurysm Repair
HOW TO DO IT
Visceral and Limb Perfusion During Thoracoabdominal Aortic Aneurysm Repair George T. Christakis, MD, Anthony Panos, MD, Charles M. Peniston, MD, Samuel V. Lichtenstein, MD, and Tomas A. Salerno, MD Division of Cardiovascular Surgery, St. Michael's Hospital and the University of Toronto, Toronto, Ontario, Canada
Patients undergoing thoracoabdominal aortic aneurysm repair are at high risk of operative morbidity and death. Aortic clamping and unclamping stresses the myocardium, interrupts visceral and limb perfusion, and leads to metabolic acidosis. Use of a simple technique to
preserve distal perfusion during the period of aortic clamping may reduce perioperative morbidity. We describe a technique of visceral and limb perfusion that may reduce surgical risk in high-risk patients. (Ann Thorac Surg 1989;48:5924)
R
Material and Methods Pa tien ts
esection of a thoracoabdominal aortic aneurysm necessitates cross-clamping of the thoracic and abdominal aorta. Concerns have been expressed since the early development of thoracic aortic surgery over the intenuption of visceral and distal limb blood flow [l]. Despite improvements in anesthetic management, aortic crossclamping results in increased myocardial work and stresses cardiac reserve in patients whose cardiac status may already be compromised [2]. Plasma epinephrine levels increase significantly during aortic clamping, with further increases in myocardial work [3]. Aortic declamping produces a decrease in mean systemic pressure and may decrease coronary blood flow. Decreased coronary perfusion combined with metabolic acidosis may cause myocardial damage in patients with coronary artery disease and ventricular dysfunction. Renal and visceral impairment after thoracoabdominal aortic operations are well-recognized complications [4, 51. Carlson and colleagues [6] demonstrated that use of a shunt during thoracic aortic operations decreased the incidence of renal failure. Crawford and associates [7] concluded from their large experience that cardiopulmonary bypass was not necessary for thoracoabdominal aortic aneurysm repair. In high-risk patients with severe coronary artery disease, ventricular dysfunction, and diffuse atherosclerosis, perfusion of viscera and limbs during thoracoabdominal aortic aneurysm repair may decrease perioperative morbidity and mortality. Distal continuous perfusion during the cross-clamp period may minimize changes in afterload and decrease cardiac stress. The incidence and extent of metabolic acidosis may also be decreased by maintenance of even limited perfusion.
Accepted for publication June 5, 1989 Address reprint requests to Dr Salemo, 3058, St. Michael's Hospital, 30 Bond St, Toronto, Ont, M5B 1W8, Canada.
0 1989 by The
Society of Thoracic Surgeons
We describe the surgical results in 3 high-risk patients undergoing thoracoabdominal aortic aneurysm repair. All 3 patients had documented coronary artery disease and poor ventricular function (ejection fraction less than 40%). One patient had cardiogenic shock, myocardial infarction, and a ruptured thoracoabdominal aortic aneurysm and underwent an emergency operation. The second patient underwent an elective operation but was at additional high risk due to previous nephrectomy. The third patient had stable exertional angina and peripheral vascular disease and also underwent an elective operation.
Surgical Technique Operative exposure was obtained through a left thoracoabdominal incision. Proximal and distal aortic control was obtained after radial division of the diaphragm and retroperitoneal exposure of the entire abdominal aorta. Both common iliac arteries were isolated. All patients were heparinized (1 mgikg sodium heparin), and the uninvolved segment of the descending thoracic aorta (proximal to the intended site of clamping) was cannulated with a 6.5-mm Moms aortic cannula. A second cannula was placed in the abdominal aorta, proximal to the bifurcation. Both cannulas were interconnected through a manifold system containing individually controlled, self-inflating balloon catheters (Fig 1). The Morris cannula was unclamped just before clamping of the thoracic and abdominal aorta. The aneurysm was incised longitudinally to just below the level of the clamp. After removal of clots and atherosclerotic debris, balloon-tipped catheters were individually inserted to perfuse the celiac axis and the superior mesenteric and renal arteries (Fig 2). All 3 patients received a HemoShield graft (24 mm). We used the inclusion technique with a circumferential running 3-0 Prolene (Ethicon) suture to attach a posterior elliptical opening in the graft to the visceral arterial orifices. The perfusion catheters were left in situ throughout the entire procedure and were brought out through the suture line at the thoracic aorta. The sutures were held
Ann Thorac Surg 1989;48:592-4
HOW TO DO IT CHRISTAMS ET AL VISCERAL PERFUSION DURING ANEURYSM REPAIR
593
Fig 1 . The catheter system used for shunting during thoracoabdominal aortic aneurysm repair includes two 6.5-mm Morris aortic cannulas interconnected by a manifold system with self-inflating balloon-tipped catheters.
under tension and were tied only after proximal and distal anastomoses had been completed and the cross-clamps and perfusion catheters had been removed.
Results The patient who had a ruptured thoracoabdominal aortic aneurysm and myocardial infarction with cardiogenic
shock died postoperatively due to extensive myocardial necrosis. The other 2 patients had an uneventful postoperative course, with extubation within 12 hours of operation and discharge from the hospital within ten days of operation. None of the patients suffered from massive head and neck and upper limb edema, as is common after thoracic aortic clamping. The average cross-clamp time was 40 minutes. The average mean arterial pressure increased from 80 to 85 mm Hg after aortic clamping and decreased to 75 mm Hg with declamping. Nitroprusside was used in 2 of 3 patients but was discontinued at the time of cross-clamping. Positive inotropic agents were not required perioperatively except for the patient in cardiogenic shock preoperatively. Arterial blood gas levels were normal in all 3 patients five minutes after aortic declamping (carbon dioxide tension, 38 mm Hg; oxygen tension, 240 mm Hg; pH, 7.42). Urinary output was maintained at greater than 30 mL/h during the cross-clamping period, with no evidence of renal dysfunction postoperatively. The average blood loss was 1,240 f 84 mL. Autotransfusion was used with the Haemonetics Cell-Saver system.
Comment
Fig 2 . Technique of simultaneous visceral and limb perfusion during thoracoabdominal aortic aneurysm repair. Arrows s h m direction of blood flow through the catheter system. Balloon-tipped catheters are inserted into the celiac axis and the superior mesenteric and renal arteries.
The operative mortality after thoracoabdominal aortic aneurysm repair vanes between 10% and 50% [4]. The incidence of renal and visceral dysfunction is high even in centers with much clinical experience [4,6]. We describe a technique of continuous visceral and limb perfusion during thoracoabdominal aortic aneurysm repair in high-risk patients. With autotransfusion, blood loss was minimal and surgical exposure was excellent. Although we did not measure flow through the catheter system or distal vascular pressures, even limited perfusion is probably superior to no perfusion under normothermic conditions. Prolonged nitroprusside infusion dur-
594
HOW TO D O IT CHRISTAMS ET AL VISCERAL PERFUSION DURING ANEURYSM REPAIR
ing aortic clamping was not necessary and metabolic acidosis was not a problem after declamping. In our experience, the maneuvers of aortic cannulation and perfusion did not add to the complexity of the operation. In this very small series of patients, we cannot provide scientific evidence of the effectiveness of this technique over that of the standard operation. We recommend, however, that the technique be considered in high-risk patients who have limited cardiac reserve and ventricular dysfunction. Further investigation with animal models and a larger surgical experience in high-risk patients will be necessary to provide validation and additional information.
References 1. Johnson J, Kirby CK, Lehr HB. A method of maintaining
adequate blood flow through the thoracic aorta while inserting
Ann Thorac Surg 1989;48:5924
an aortic graft to replace the aortic aneurysm. Surgery 1955; 3754-7. 2. Kalman PG, Wellwood MR, Weisel RD, et al. Cardiac dysfunction during abdominal aortic surgery: the limitations of pulmonary wedge pressure. J Vasc Surg 1986;3:773-81. 3. Symbas PN, Pfaender LM, Drucker MH, Lester JL, Gravanis MB, Zacharapoulos L. Cross-clamping of the descending aorta. J Thorac Cardiovasc Surg 1983;85:300-8. 4. Crawford ES, Snyder DM, Cho GC, Roehm JOF. Progress in treatment of thoracoabdominal and abdominal aortic aneurysm involving celiac, superior mesenteric and renal arteries. Ann Surg 1978;188:404-11. 5. Oyoma M, McNamara J, Shehiro GT, et al. The effects of thoracic aortic cross-damping and dedamping in visceral organ blood flow. Ann Surg 1983;197459-62. 6. Carlson DE,Karp RB, Kouchoukos NT. Surgical treatment of aneurysms of the descending thoracic aorta: an analysis of 85 patients. Ann Thorac Surg 1983;35:5W. 7. Crawford ES, Walker HSJ, Saleh SA, Norman NA. Graft replacement of aneurysm in descending thoracic aorta: results without bypass or shunting. Surgery 1981;8973-9.
Visceral and Limb Perfusion During Thoracoabdominal Aortic Aneurysm Repair George T. Christakis, MD, Anthony Panos, MD, Charles M. Peniston, MD, Samuel V. Lichtenstein, MD, and Tomas A. Salerno, MD Division of Cardiovascular Surgery, St. Michael's Hospital and the University of Toronto, Toronto, Ontario, Canada
Patients undergoing thoracoabdominal aortic aneurysm repair are at high risk of operative morbidity and death. Aortic clamping and unclamping stresses the myocardium, interrupts visceral and limb perfusion, and leads to metabolic acidosis. Use of a simple technique to
preserve distal perfusion during the period of aortic clamping may reduce perioperative morbidity. We describe a technique of visceral and limb perfusion that may reduce surgical risk in high-risk patients. (Ann Thorac Surg 1989;48:5924)
R
Material and Methods Pa tien ts
esection of a thoracoabdominal aortic aneurysm necessitates cross-clamping of the thoracic and abdominal aorta. Concerns have been expressed since the early development of thoracic aortic surgery over the intenuption of visceral and distal limb blood flow [l]. Despite improvements in anesthetic management, aortic crossclamping results in increased myocardial work and stresses cardiac reserve in patients whose cardiac status may already be compromised [2]. Plasma epinephrine levels increase significantly during aortic clamping, with further increases in myocardial work [3]. Aortic declamping produces a decrease in mean systemic pressure and may decrease coronary blood flow. Decreased coronary perfusion combined with metabolic acidosis may cause myocardial damage in patients with coronary artery disease and ventricular dysfunction. Renal and visceral impairment after thoracoabdominal aortic operations are well-recognized complications [4, 51. Carlson and colleagues [6] demonstrated that use of a shunt during thoracic aortic operations decreased the incidence of renal failure. Crawford and associates [7] concluded from their large experience that cardiopulmonary bypass was not necessary for thoracoabdominal aortic aneurysm repair. In high-risk patients with severe coronary artery disease, ventricular dysfunction, and diffuse atherosclerosis, perfusion of viscera and limbs during thoracoabdominal aortic aneurysm repair may decrease perioperative morbidity and mortality. Distal continuous perfusion during the cross-clamp period may minimize changes in afterload and decrease cardiac stress. The incidence and extent of metabolic acidosis may also be decreased by maintenance of even limited perfusion.
Accepted for publication June 5, 1989 Address reprint requests to Dr Salemo, 3058, St. Michael's Hospital, 30 Bond St, Toronto, Ont, M5B 1W8, Canada.
0 1989 by The
Society of Thoracic Surgeons
We describe the surgical results in 3 high-risk patients undergoing thoracoabdominal aortic aneurysm repair. All 3 patients had documented coronary artery disease and poor ventricular function (ejection fraction less than 40%). One patient had cardiogenic shock, myocardial infarction, and a ruptured thoracoabdominal aortic aneurysm and underwent an emergency operation. The second patient underwent an elective operation but was at additional high risk due to previous nephrectomy. The third patient had stable exertional angina and peripheral vascular disease and also underwent an elective operation.
Surgical Technique Operative exposure was obtained through a left thoracoabdominal incision. Proximal and distal aortic control was obtained after radial division of the diaphragm and retroperitoneal exposure of the entire abdominal aorta. Both common iliac arteries were isolated. All patients were heparinized (1 mgikg sodium heparin), and the uninvolved segment of the descending thoracic aorta (proximal to the intended site of clamping) was cannulated with a 6.5-mm Moms aortic cannula. A second cannula was placed in the abdominal aorta, proximal to the bifurcation. Both cannulas were interconnected through a manifold system containing individually controlled, self-inflating balloon catheters (Fig 1). The Morris cannula was unclamped just before clamping of the thoracic and abdominal aorta. The aneurysm was incised longitudinally to just below the level of the clamp. After removal of clots and atherosclerotic debris, balloon-tipped catheters were individually inserted to perfuse the celiac axis and the superior mesenteric and renal arteries (Fig 2). All 3 patients received a HemoShield graft (24 mm). We used the inclusion technique with a circumferential running 3-0 Prolene (Ethicon) suture to attach a posterior elliptical opening in the graft to the visceral arterial orifices. The perfusion catheters were left in situ throughout the entire procedure and were brought out through the suture line at the thoracic aorta. The sutures were held
Ann Thorac Surg 1989;48:592-4
HOW TO DO IT CHRISTAMS ET AL VISCERAL PERFUSION DURING ANEURYSM REPAIR
593
Fig 1 . The catheter system used for shunting during thoracoabdominal aortic aneurysm repair includes two 6.5-mm Morris aortic cannulas interconnected by a manifold system with self-inflating balloon-tipped catheters.
under tension and were tied only after proximal and distal anastomoses had been completed and the cross-clamps and perfusion catheters had been removed.
Results The patient who had a ruptured thoracoabdominal aortic aneurysm and myocardial infarction with cardiogenic
shock died postoperatively due to extensive myocardial necrosis. The other 2 patients had an uneventful postoperative course, with extubation within 12 hours of operation and discharge from the hospital within ten days of operation. None of the patients suffered from massive head and neck and upper limb edema, as is common after thoracic aortic clamping. The average cross-clamp time was 40 minutes. The average mean arterial pressure increased from 80 to 85 mm Hg after aortic clamping and decreased to 75 mm Hg with declamping. Nitroprusside was used in 2 of 3 patients but was discontinued at the time of cross-clamping. Positive inotropic agents were not required perioperatively except for the patient in cardiogenic shock preoperatively. Arterial blood gas levels were normal in all 3 patients five minutes after aortic declamping (carbon dioxide tension, 38 mm Hg; oxygen tension, 240 mm Hg; pH, 7.42). Urinary output was maintained at greater than 30 mL/h during the cross-clamping period, with no evidence of renal dysfunction postoperatively. The average blood loss was 1,240 f 84 mL. Autotransfusion was used with the Haemonetics Cell-Saver system.
Comment
Fig 2 . Technique of simultaneous visceral and limb perfusion during thoracoabdominal aortic aneurysm repair. Arrows s h m direction of blood flow through the catheter system. Balloon-tipped catheters are inserted into the celiac axis and the superior mesenteric and renal arteries.
The operative mortality after thoracoabdominal aortic aneurysm repair vanes between 10% and 50% [4]. The incidence of renal and visceral dysfunction is high even in centers with much clinical experience [4,6]. We describe a technique of continuous visceral and limb perfusion during thoracoabdominal aortic aneurysm repair in high-risk patients. With autotransfusion, blood loss was minimal and surgical exposure was excellent. Although we did not measure flow through the catheter system or distal vascular pressures, even limited perfusion is probably superior to no perfusion under normothermic conditions. Prolonged nitroprusside infusion dur-
594
HOW TO D O IT CHRISTAMS ET AL VISCERAL PERFUSION DURING ANEURYSM REPAIR
ing aortic clamping was not necessary and metabolic acidosis was not a problem after declamping. In our experience, the maneuvers of aortic cannulation and perfusion did not add to the complexity of the operation. In this very small series of patients, we cannot provide scientific evidence of the effectiveness of this technique over that of the standard operation. We recommend, however, that the technique be considered in high-risk patients who have limited cardiac reserve and ventricular dysfunction. Further investigation with animal models and a larger surgical experience in high-risk patients will be necessary to provide validation and additional information.
References 1. Johnson J, Kirby CK, Lehr HB. A method of maintaining
adequate blood flow through the thoracic aorta while inserting
Ann Thorac Surg 1989;48:5924
an aortic graft to replace the aortic aneurysm. Surgery 1955; 3754-7. 2. Kalman PG, Wellwood MR, Weisel RD, et al. Cardiac dysfunction during abdominal aortic surgery: the limitations of pulmonary wedge pressure. J Vasc Surg 1986;3:773-81. 3. Symbas PN, Pfaender LM, Drucker MH, Lester JL, Gravanis MB, Zacharapoulos L. Cross-clamping of the descending aorta. J Thorac Cardiovasc Surg 1983;85:300-8. 4. Crawford ES, Snyder DM, Cho GC, Roehm JOF. Progress in treatment of thoracoabdominal and abdominal aortic aneurysm involving celiac, superior mesenteric and renal arteries. Ann Surg 1978;188:404-11. 5. Oyoma M, McNamara J, Shehiro GT, et al. The effects of thoracic aortic cross-damping and dedamping in visceral organ blood flow. Ann Surg 1983;197459-62. 6. Carlson DE,Karp RB, Kouchoukos NT. Surgical treatment of aneurysms of the descending thoracic aorta: an analysis of 85 patients. Ann Thorac Surg 1983;35:5W. 7. Crawford ES, Walker HSJ, Saleh SA, Norman NA. Graft replacement of aneurysm in descending thoracic aorta: results without bypass or shunting. Surgery 1981;8973-9.