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Right thoracotomy for reoperative right coronary artery bypass procedures
Right Thoracotomy for Reoperative Right Coronary Artery Bypass Procedures Rakesh Uppal, FRCS, Walter G. Wolfe, MD, James E. Lowe, MD, and Peter K. Smith, MD Department of Surgery, Duke University Medical Center, Durham. North Carolina
The use of a right thoracotomy is a safe alternative approach for reentering the mediastinum for reoperative right coronary artery bypass grafting. This technique was used in 9 patients and allowed minimal dissection, reducing the risks of hemorrhage and injury to previously placed patent grafts. Cardiopulmonary bypass was used in 4 patients in whom myocardial protection was accomplished with systemic hypothermia. Right atrial cannulation provided adequate venous return, with arterial inflow established via the femoral artery (n = 2) or
ascending aorta (n = 2). In 5 patients, revascularization was accomplished by temporary coronary artery occlusion without cardiopulmonary support. There were no deaths, and postoperative recovery was not delayed. Postoperative chest drainage (mean f standard deviation, 1,076 f 718 mL) was significantly less ( p < 0.01) than redo median sternotomy (1,352 f 602 mL) in a similar population. Eight of 9 patients remain free of angina 29 2 24.8 months postoperatively. (Ann Thorac Surg 1994;57:123-5)
R
induction of anesthesia, the patients were intubated with a double-lumen endotracheal tube to permit selective ventilation. All patients underwent grafting of the right coronary system using either the right IMA (RIMA) or a reversed SVG. An external defibrillating pad was attached to the left posterior chest and the patient rotated 45 degrees into the right anterolateral position as shown in Figure 1. The chest was entered through the fourth intercostal space with simultaneous exposure of the right femoral artery and harvesting of a segment of sayhenous vein if required. The ascending aorta may also be used for arterial cannulation. The preferred method of venous cannulation was to establish return from the right atrium (3/9), although in 1 patient the superior vena cava and right femoral vein were individually cannulated. Cardiopulmonary bypass was not used in 5 patients. Of these, 3 patients had 100% occlusion of the RCA, 1 was an angioplasty failure, and the fifth had a 95% RCA occlusion. A variety of techniques were used to protect the heart, based primarily on systemic hypothermia without crossclamping. Three patients were cooled to 32°C. One patient was cooled to 22°C with 16 minutes of intermittent circulatory arrest to repair a false aneurysm at the proximal anastomosis of a previously placed right SVG. Adequate decompression was achieved in all but the latter patient, who was vented through the right superior pulmonary vein. This patient had four normally functioning grafts in situ. The procedure for grafting was as follows (Figs 2, 3): Once the pericardium had been opened and the vessel isolated, two 2-0 silk sutures were placed in the myocardium encircling the coronary artery. Moderate tension on the sutures allowed a bloodless and relatively motionless field for operation. The coronary artery was dissected and
edo coronary artery bypass grafting is becoming common worldwide and now constitutes a substantial proportion of a cardiac surgeon’s practice. These procedures will increase in number in the future [l]. Redo sternotomy has been associated with increased morbidity and mortality due to the risk of reentering the surgical plane where adhesions may be dense and normal anatomical landmarks obliterated [2]. The presence of patent grafts, especially to the anterior surface of the heart, compounds this risk and has become more common with the preferential use of internal mammary artery (IMA) grafts. Injury to a patent graft where myocardial perfusion is graft dependent has been associated with a mortality rate of up to 50% [3]. In the presence of a functioning IMA graft, myocardial protection requires dissection of the IMA to control it, further increasing the risk to it. The manipulation and handling of diseased saphenous vein grafts (SVGs) can result in embolization into the native coronary circulation with consequent morbidity or mortality [4, 51. The mediastinum has traditionally been reentered through a median sternotomy, but there have been numerous reports in the literature on the use of a left thoracotomy for revascularization of the left anterior descending artery and circumflex artery territories [6-121. The present report describes 9 patients in whom a right anterior or lateral thoracotomy was used to revascularize the distal right coronary artery (RCA) circulation.
Material and Methods Nine patients underwent myocardial revascularization through a right anterior or lateral thoracotomy. After Accepted for publication Feb 19, 1993. Address reprint requests to Dr Smith, Duke University Medical Center, Box 3442, Durham, NC 27710.
0 1YY4 by The Society of Thoracic Surgeons
0003-4975/Y4/$7.00
124
UPPAL ET AL RIGHT THORACOTOMY FOR REOPERATIVE CORONARY PROCEDURES
Ann Thorac Surg 1994;5712b5
Pericar,dium DA \
.
.I
Corn anas Fig 3. Completed anastomosis at the crux of the right coronary ar tery. (PDA = posterior descending artery.) Fig 1. Lateral incision with patient rotated to 45 degrees.
opened, and a previously prepared RIMA or SVG was anastomosed using a standard technique. In 1 patient the RIMA was anastomosed to the distal portion of a previously placed vein graft. Exposure permitted grafting of the RCA as far distal as the origin of the posterior descending coronary artery. In those patients in whom an SVG was performed, the proximal anastomosis was made to the aorta. Table 1 summarizes clinical data on the 9 patients who underwent a right thoracotomy. All patients had a technically satisfactory operation and postoperative ventilation times were not prolonged, with a mean time of 15 hours. The mean blood loss for these patients was 1,075 f 718 mL, which was significantly less than that of standard redo
Fig 2. Right coronary artery (RCA) isolated on two slings with a previously dissected internal mamma ry arte y (IMA) in the operative field.
procedures (1,352 ? 602 mL) in a similar patient population at this institution ( p < 0.01). 'There were no deaths. Eight of these 9 patients have remained free of angina (mean follow up 29 months; range, 2 to 72 months). One patient (patient 7) required further operatlon 2 years after the reported operation. At that time, a median stemotomy incision was used to perform a left IMA (LIMA) graft to the left anterior descending artery and an SVG to the RCA.
Comment The number of patients with SVG stenosis requiring reoperative surgical procedures is increasing [ 11. This is related to the increasing use of the LIMA graft and its superior long-term patency rate. The use of a right thoracotomy [13] is an alternative means to revascularize the right coronary system. These procedures were performed in highly selected patients in whom coronary artery anatomy and coronary lesion distribution were suitable. It should be emphasized that exposure for grafting of the proximal posterior descending coronary artery is extremely difficult through this approach, which should be considered only when grafting of the idistal RCA will provide satisfactory results. The patients described represent only 2% (9 of 525) of redo coronary operations performed in the same period. With proper selection, excellent results can be obtained. The use of this approach allows the LIMA graft to remain undisturbed and free from the risk of accidental transection, with its attendant mortality. A lateral, as opposed to an anterior, thoracotomy allows better exposure of the RlMA and is recommended for those patients undergoing IMA grafting. With their limited anterior or lateral incisions patients require only standard methods of analgesia. More sophisticated methods of analgesia such as epidural or continuous paravertebral blocks would be required if a more extensive posterolateral approach were used. The preferred method of myocardial protection was systemic hypothermia, allowing the heart to fibrillate while the distal anastomosis was being performed. Left anterior and posterior external defibrillating pads are placed before skin preparation to permit external defibril-
UPPAL ET AL RIGHT THORACOTOMY FOR REOPERATIVE CORONARY PROCEDURES
Ann Thorac Surg 1994:5712>5
125
Table 1 . Preoperative and Postoperative Characteristics Patient No.
Age Sex (y)
Previous Operation
Reoperation
Cannulation
Myocardial Protection
Blood Loss (mL)
Ventilation Time (h)
No CPB
None
350
12
No CPB
None
560
13
No CPB
None
560
10
No CPB
None
1,200
24
68
CABG x 3,1984
R1MA-t RCA, 1992 RIMAjRCA, 1992 RIMAjRCA, 1991 RIMAjRCA, 1991 S V G R C A . 1991
Fem, RA
32°C; no CC
1,900
19
M
55
No CPB
None
1,865
21
M
62
CABG X 2, 1990; RIMAjRCA, 1990 mediastinitis CABG x 3, 1983 S V G R C A , 1991
Aorta, RA
32T, no CC
2,160
11
M
65
CABG x 5, 1986
Fem/fem and
22°C; no CC
505
13
F
49
CABG
Aorta, RA
32°C; no CC
560
11
M
50
CABG x 3, 1981
M
69
CABG x 2, 1976
M
40
CABG
M
73
CABG x 2, 1972
M
X
X
1, 1984
5, 1981
Repair RCA graft aneurysm, 1986 RIMAjRCA, 1986
svc
Outcome Discharge home, no angina Discharge home, no angina Discharge home, no angina Discharge home, no angina Discharge home, no angina Discharge home, no angina Discharge home; redo CABG, 1992 Discharge home, no angina Discharge home, no angina
CABG = coronary artery bypass grafting; CC = cross-clamp; CPB = cardiopulmonary bypass; Fem = femoral artery; RA = right SVG = saphenous vein graft. SVC = superior vena cava; RIMA = right internal mammary artery; atrium; RCA = right coronary artery;
lation. After right thoracotomy exposure, one of these pads may be coupled with a single internal paddle, which allows safe defibrillation despite the limited cardiac dissection this technique espouses. In 5 patients in whom there was complete or almost complete occlusion of both the native RCA and its graft, an RIMA graft to the distal right coronary system was performed without using cardiopulmonary bypass. This approach for redo coronary artery bypass grafting can be recommended in those patients who have a patent LIMA graft, those who have had mediastinitis with pectoral flaps rotated which may further obliterate the surgical plane, those who have undergone irradiation to the mediastinum, and those patients who have a right-sided pulmonary lesion requiring concomitant resection. The rapidity of exposure compared with standard redo sternotomy may also benefit unstable patients with RCA lesions after failure of percutaneous transluminal coronary angioplasty. In addition, this approach is potentially beneficial in diabetic patients who had a LIMA dissected previously and in whom an RIMA graft is being contemplated. These patients have been shown to have a higher risk of infection when a median sternotomy incision is used [14]. Rakesh Uppal was supported in part by a Kings Fund Traveling scholarship and a scholarship from the Cardiothoracic Society of Great Britain.
References 1. Lytle BW, Loop FD, Taylor PC, et al. Vein graft disease: the clinical impact of stenoses in saphenous vein bypass grafts to coronary arteries. J Thorac Cardiovasc Surg 1992;103:83140.
2. Loop FD. Catastrophic hemorrhage during sternal reentry (Editorial]. Ann Thorac Surg 1984;37:271-2. 3. Dobell AR, Jain AK. Catastrophic hemorrhage during redo sternotomy. Ann Thorac Surg 1984;37273-8. 4. Keon WJ, Heggtveit HA, Leduc J. Perioperative myocardial infarction caused by atheroembolism. J Thorac Cardiovasc Surg 1982;84:849-55. 5. Grondin CM, Pomar JL, Hebert Y, et al. Reoperation in patients with patent atherosclerotic coronary vein grafts. A different approach to a different disease. J Thorac Cardiovasc Surg 1984;87:379-85. 6. Grosner G, Lajos TZ, Schimert G, Bergsland J. Left thoracotomy reoperation for coronary artery disease. J Cardiac Surg 1990;5:304-8. 7. Faro RS, ]avid H, Najafi H, et al. Left thoracotomy for reoperation for coronary revascularization. J Thorac Cardiovasc Surg 1982;84:45>5. 8. Cheung D, Flemma RJ, Mullen DC, Lepley D Jr. An alternative approach to isolated circumflex coronary bypass reoperations. Ann Thorac Surg 1982;33:302-3. 9. Ungerleider RM, Mills NL, Wechsler AS. Left thoracotomy for reoperative coronary artery bypass procedures. Ann Thorac Surg 1985;40:11-5. 10. Burlingame MW, Bonchek LI, Vazales BE. Left thoracotomy for reoperative coronary bypass. J Thorac Cardiovasc Surg 1988;95:5Of%lO. 11. Gandjbakhch I, Acar C, Cabrol C. Left thoracotomy approach for coronary artery bypass grafting in patients with pericardial adhesions. Ann Thorac Surg 1989;48:871-3. 12. Borst HG. Leftsided thoracotomy for coronary artery reoperation. Thoraxchir Vask Chir 1978;26:9.57. 13. Walker WS, Sang CT. Avoidance of patent anterior grafts at revisional coronary artery surgery: use of a lateral thoracotomy approach. Thorax 1986;41:692-5. 14. Loop FD, Lytle BW, Cosgrove DM, et al. Sternal wound complications after isolated coronary artery bypass grafting: early and late mortality, morbidity, and cost of care. Ann Thorac Surg 1990;49:179-87.
The use of a right thoracotomy is a safe alternative approach for reentering the mediastinum for reoperative right coronary artery bypass grafting. This technique was used in 9 patients and allowed minimal dissection, reducing the risks of hemorrhage and injury to previously placed patent grafts. Cardiopulmonary bypass was used in 4 patients in whom myocardial protection was accomplished with systemic hypothermia. Right atrial cannulation provided adequate venous return, with arterial inflow established via the femoral artery (n = 2) or
ascending aorta (n = 2). In 5 patients, revascularization was accomplished by temporary coronary artery occlusion without cardiopulmonary support. There were no deaths, and postoperative recovery was not delayed. Postoperative chest drainage (mean f standard deviation, 1,076 f 718 mL) was significantly less ( p < 0.01) than redo median sternotomy (1,352 f 602 mL) in a similar population. Eight of 9 patients remain free of angina 29 2 24.8 months postoperatively. (Ann Thorac Surg 1994;57:123-5)
R
induction of anesthesia, the patients were intubated with a double-lumen endotracheal tube to permit selective ventilation. All patients underwent grafting of the right coronary system using either the right IMA (RIMA) or a reversed SVG. An external defibrillating pad was attached to the left posterior chest and the patient rotated 45 degrees into the right anterolateral position as shown in Figure 1. The chest was entered through the fourth intercostal space with simultaneous exposure of the right femoral artery and harvesting of a segment of sayhenous vein if required. The ascending aorta may also be used for arterial cannulation. The preferred method of venous cannulation was to establish return from the right atrium (3/9), although in 1 patient the superior vena cava and right femoral vein were individually cannulated. Cardiopulmonary bypass was not used in 5 patients. Of these, 3 patients had 100% occlusion of the RCA, 1 was an angioplasty failure, and the fifth had a 95% RCA occlusion. A variety of techniques were used to protect the heart, based primarily on systemic hypothermia without crossclamping. Three patients were cooled to 32°C. One patient was cooled to 22°C with 16 minutes of intermittent circulatory arrest to repair a false aneurysm at the proximal anastomosis of a previously placed right SVG. Adequate decompression was achieved in all but the latter patient, who was vented through the right superior pulmonary vein. This patient had four normally functioning grafts in situ. The procedure for grafting was as follows (Figs 2, 3): Once the pericardium had been opened and the vessel isolated, two 2-0 silk sutures were placed in the myocardium encircling the coronary artery. Moderate tension on the sutures allowed a bloodless and relatively motionless field for operation. The coronary artery was dissected and
edo coronary artery bypass grafting is becoming common worldwide and now constitutes a substantial proportion of a cardiac surgeon’s practice. These procedures will increase in number in the future [l]. Redo sternotomy has been associated with increased morbidity and mortality due to the risk of reentering the surgical plane where adhesions may be dense and normal anatomical landmarks obliterated [2]. The presence of patent grafts, especially to the anterior surface of the heart, compounds this risk and has become more common with the preferential use of internal mammary artery (IMA) grafts. Injury to a patent graft where myocardial perfusion is graft dependent has been associated with a mortality rate of up to 50% [3]. In the presence of a functioning IMA graft, myocardial protection requires dissection of the IMA to control it, further increasing the risk to it. The manipulation and handling of diseased saphenous vein grafts (SVGs) can result in embolization into the native coronary circulation with consequent morbidity or mortality [4, 51. The mediastinum has traditionally been reentered through a median sternotomy, but there have been numerous reports in the literature on the use of a left thoracotomy for revascularization of the left anterior descending artery and circumflex artery territories [6-121. The present report describes 9 patients in whom a right anterior or lateral thoracotomy was used to revascularize the distal right coronary artery (RCA) circulation.
Material and Methods Nine patients underwent myocardial revascularization through a right anterior or lateral thoracotomy. After Accepted for publication Feb 19, 1993. Address reprint requests to Dr Smith, Duke University Medical Center, Box 3442, Durham, NC 27710.
0 1YY4 by The Society of Thoracic Surgeons
0003-4975/Y4/$7.00
124
UPPAL ET AL RIGHT THORACOTOMY FOR REOPERATIVE CORONARY PROCEDURES
Ann Thorac Surg 1994;5712b5
Pericar,dium DA \
.
.I
Corn anas Fig 3. Completed anastomosis at the crux of the right coronary ar tery. (PDA = posterior descending artery.) Fig 1. Lateral incision with patient rotated to 45 degrees.
opened, and a previously prepared RIMA or SVG was anastomosed using a standard technique. In 1 patient the RIMA was anastomosed to the distal portion of a previously placed vein graft. Exposure permitted grafting of the RCA as far distal as the origin of the posterior descending coronary artery. In those patients in whom an SVG was performed, the proximal anastomosis was made to the aorta. Table 1 summarizes clinical data on the 9 patients who underwent a right thoracotomy. All patients had a technically satisfactory operation and postoperative ventilation times were not prolonged, with a mean time of 15 hours. The mean blood loss for these patients was 1,075 f 718 mL, which was significantly less than that of standard redo
Fig 2. Right coronary artery (RCA) isolated on two slings with a previously dissected internal mamma ry arte y (IMA) in the operative field.
procedures (1,352 ? 602 mL) in a similar patient population at this institution ( p < 0.01). 'There were no deaths. Eight of these 9 patients have remained free of angina (mean follow up 29 months; range, 2 to 72 months). One patient (patient 7) required further operatlon 2 years after the reported operation. At that time, a median stemotomy incision was used to perform a left IMA (LIMA) graft to the left anterior descending artery and an SVG to the RCA.
Comment The number of patients with SVG stenosis requiring reoperative surgical procedures is increasing [ 11. This is related to the increasing use of the LIMA graft and its superior long-term patency rate. The use of a right thoracotomy [13] is an alternative means to revascularize the right coronary system. These procedures were performed in highly selected patients in whom coronary artery anatomy and coronary lesion distribution were suitable. It should be emphasized that exposure for grafting of the proximal posterior descending coronary artery is extremely difficult through this approach, which should be considered only when grafting of the idistal RCA will provide satisfactory results. The patients described represent only 2% (9 of 525) of redo coronary operations performed in the same period. With proper selection, excellent results can be obtained. The use of this approach allows the LIMA graft to remain undisturbed and free from the risk of accidental transection, with its attendant mortality. A lateral, as opposed to an anterior, thoracotomy allows better exposure of the RlMA and is recommended for those patients undergoing IMA grafting. With their limited anterior or lateral incisions patients require only standard methods of analgesia. More sophisticated methods of analgesia such as epidural or continuous paravertebral blocks would be required if a more extensive posterolateral approach were used. The preferred method of myocardial protection was systemic hypothermia, allowing the heart to fibrillate while the distal anastomosis was being performed. Left anterior and posterior external defibrillating pads are placed before skin preparation to permit external defibril-
UPPAL ET AL RIGHT THORACOTOMY FOR REOPERATIVE CORONARY PROCEDURES
Ann Thorac Surg 1994:5712>5
125
Table 1 . Preoperative and Postoperative Characteristics Patient No.
Age Sex (y)
Previous Operation
Reoperation
Cannulation
Myocardial Protection
Blood Loss (mL)
Ventilation Time (h)
No CPB
None
350
12
No CPB
None
560
13
No CPB
None
560
10
No CPB
None
1,200
24
68
CABG x 3,1984
R1MA-t RCA, 1992 RIMAjRCA, 1992 RIMAjRCA, 1991 RIMAjRCA, 1991 S V G R C A . 1991
Fem, RA
32°C; no CC
1,900
19
M
55
No CPB
None
1,865
21
M
62
CABG X 2, 1990; RIMAjRCA, 1990 mediastinitis CABG x 3, 1983 S V G R C A , 1991
Aorta, RA
32T, no CC
2,160
11
M
65
CABG x 5, 1986
Fem/fem and
22°C; no CC
505
13
F
49
CABG
Aorta, RA
32°C; no CC
560
11
M
50
CABG x 3, 1981
M
69
CABG x 2, 1976
M
40
CABG
M
73
CABG x 2, 1972
M
X
X
1, 1984
5, 1981
Repair RCA graft aneurysm, 1986 RIMAjRCA, 1986
svc
Outcome Discharge home, no angina Discharge home, no angina Discharge home, no angina Discharge home, no angina Discharge home, no angina Discharge home, no angina Discharge home; redo CABG, 1992 Discharge home, no angina Discharge home, no angina
CABG = coronary artery bypass grafting; CC = cross-clamp; CPB = cardiopulmonary bypass; Fem = femoral artery; RA = right SVG = saphenous vein graft. SVC = superior vena cava; RIMA = right internal mammary artery; atrium; RCA = right coronary artery;
lation. After right thoracotomy exposure, one of these pads may be coupled with a single internal paddle, which allows safe defibrillation despite the limited cardiac dissection this technique espouses. In 5 patients in whom there was complete or almost complete occlusion of both the native RCA and its graft, an RIMA graft to the distal right coronary system was performed without using cardiopulmonary bypass. This approach for redo coronary artery bypass grafting can be recommended in those patients who have a patent LIMA graft, those who have had mediastinitis with pectoral flaps rotated which may further obliterate the surgical plane, those who have undergone irradiation to the mediastinum, and those patients who have a right-sided pulmonary lesion requiring concomitant resection. The rapidity of exposure compared with standard redo sternotomy may also benefit unstable patients with RCA lesions after failure of percutaneous transluminal coronary angioplasty. In addition, this approach is potentially beneficial in diabetic patients who had a LIMA dissected previously and in whom an RIMA graft is being contemplated. These patients have been shown to have a higher risk of infection when a median sternotomy incision is used [14]. Rakesh Uppal was supported in part by a Kings Fund Traveling scholarship and a scholarship from the Cardiothoracic Society of Great Britain.
References 1. Lytle BW, Loop FD, Taylor PC, et al. Vein graft disease: the clinical impact of stenoses in saphenous vein bypass grafts to coronary arteries. J Thorac Cardiovasc Surg 1992;103:83140.
2. Loop FD. Catastrophic hemorrhage during sternal reentry (Editorial]. Ann Thorac Surg 1984;37:271-2. 3. Dobell AR, Jain AK. Catastrophic hemorrhage during redo sternotomy. Ann Thorac Surg 1984;37273-8. 4. Keon WJ, Heggtveit HA, Leduc J. Perioperative myocardial infarction caused by atheroembolism. J Thorac Cardiovasc Surg 1982;84:849-55. 5. Grondin CM, Pomar JL, Hebert Y, et al. Reoperation in patients with patent atherosclerotic coronary vein grafts. A different approach to a different disease. J Thorac Cardiovasc Surg 1984;87:379-85. 6. Grosner G, Lajos TZ, Schimert G, Bergsland J. Left thoracotomy reoperation for coronary artery disease. J Cardiac Surg 1990;5:304-8. 7. Faro RS, ]avid H, Najafi H, et al. Left thoracotomy for reoperation for coronary revascularization. J Thorac Cardiovasc Surg 1982;84:45>5. 8. Cheung D, Flemma RJ, Mullen DC, Lepley D Jr. An alternative approach to isolated circumflex coronary bypass reoperations. Ann Thorac Surg 1982;33:302-3. 9. Ungerleider RM, Mills NL, Wechsler AS. Left thoracotomy for reoperative coronary artery bypass procedures. Ann Thorac Surg 1985;40:11-5. 10. Burlingame MW, Bonchek LI, Vazales BE. Left thoracotomy for reoperative coronary bypass. J Thorac Cardiovasc Surg 1988;95:5Of%lO. 11. Gandjbakhch I, Acar C, Cabrol C. Left thoracotomy approach for coronary artery bypass grafting in patients with pericardial adhesions. Ann Thorac Surg 1989;48:871-3. 12. Borst HG. Leftsided thoracotomy for coronary artery reoperation. Thoraxchir Vask Chir 1978;26:9.57. 13. Walker WS, Sang CT. Avoidance of patent anterior grafts at revisional coronary artery surgery: use of a lateral thoracotomy approach. Thorax 1986;41:692-5. 14. Loop FD, Lytle BW, Cosgrove DM, et al. Sternal wound complications after isolated coronary artery bypass grafting: early and late mortality, morbidity, and cost of care. Ann Thorac Surg 1990;49:179-87.