Scand J Thor Cardiovasc Surg 26: 57-59, 1992
PATENCY OF THE INTERNAL MAMMARY ARTERY USED AS SEQUENTIAL GRAFT Jon Aksnes,' Kenneth Nordstrand,' Harald Lindberg,' Oddbjrarn Christensen,' Karleiv Vatne,*Otto Smiseth3 and Tor Froysaker' From the Departments of 'Surgery, 'Radiology and 3Medicine, Rikshospitalet, Oslo, Norway
Scand Cardiovasc J Downloaded from informahealthcare.com by Queen's University on 01/04/15 For personal use only.
(Accepted for publication July 5, 1991)
Abstract. In 28 patients with the left internal mammary artery (IMA) used as a sequential coronary artery graft, clinical and angiographic evaluation was made 19-47 months postoperatively. Patency was 96% in the proximal anastomoses and 93 Yo in all the anastomoses. Angiography, however, showed optimal function in only 75% of the distal graft ends. These observations indicate that routine use of left IMA as a sequential graft should be restricted to experienced surgeons. Clinical and angiographic findings did not always correlate, emphasizing that evaluation of IMA-graft patency should include angiography. Key words: IMA, sequential IMA-graft patency, angiography.
years. Table I presents a clinical profile. Two patients had significant left main stem stenosis. One of them was the only patient with unstable angina at the time of surgery. No patient had left ventricular aneurysm. Three patients had an isolated stenotic lesion of the left anterior descending (LAD) artery system and required only a sequential IMA graft. The others had triple vessel disease. No patient had previous heart surgery, but one had twice undergone percutaneous transluminal coronary angioplasty. The surgical technique was as earlier described (2, 4). Sequential procedure was used when the stenotic processes were localized so that two of either distal LAD, left 1st diagonal (LAD 1) or left 2nd diagonal (LD 2) required bypass. For other vessels needing bypass we used reversed saphenous vein as a single or as a sequential graft. The sites of anastomosis are listed in Table I1 and intraoperative data in Table 111. The only additional
Although the long-term patency of single internal mammary artery (IMA) grafts has proved superior to that of saphenous vein grafts (1, 3, 51, the patency of IMA as a sequential graft is not well documented angiographically. This Table I. Preoerative clinical data (28 patients) study presents both clinical and angiographic follow-up results from sequential antegrade No. of IMA-graft ing . patients Data ~~
MATERIAL AND METHODS During 20 months up to June 1989, a total of 32 patients underwent coronary artery bypass using IMA as a sequential graft. There was no hospital mortality. Two patients died at home 10 and 30 months postoperatively, one suddenly without prior symptoms of cardiac ischemia. The other patient had had myocardial infarction on postoperative day I and after discharge developed angina and dyspnea. Two survivors were not available for follow-up. One was a 36-yearold diabetic with postoperative renal failure and subsequent cerebral insult. He is now free from coronary ischemia and has received a kidney transplant. The second patient refused angiography. The study thus comprised 28 patients (only 4 women) with a mean age at operation of 59 (range 39-79)
NYHA function class I1 111 IV Left ventricular end-diastolic pressure > 25 mmHg Left ventricular ejection fraction t40% Arteriosclerosis obliterans Previous acute myocardial infarction Diabetes mellitus Hyperlipidemia Arterial hypertension
3 20 5
2 2 8 16 1
12 9
Duration of angina pectoris (years): mean 4.4, range 0.25-10. Scand J Thoracic 26
58
J. Alcsnes et al.
Table 11. Anastomoses to coronary arteries Grafts
Scand Cardiovasc J Downloaded from informahealthcare.com by Queen's University on 01/04/15 For personal use only.
IMA LAD LD 1 LD 2 Vein Simple Sequential
Table IV. Clinical data ab follow-up evaluation
No. of anastomoses
Data
26 19 11
Angina pectoris Dyspnea Fatigue NYHA function class I
I1
24 36
No. of patients 7 7 I 14
13
111
1
IV
0
The follow-up interval averaged 28 (range 19-47) months. Seven patients complained of recurrent angina. Table IV summarizes the clinical status. At exercise stress testing 17 patients had no symptoms or electrocardiographic
signs of cardiac ischemia, and thus only their IMA grafts were angiographically visualized. In the remaining 11 patients, with positive or inconclusive stress test, a full angiographic examination was performed. There were no complications of follow-up angiography. Table V shows the angiographic evaluation of the IMA grafts. Only one (in the patient with sternal osteomyelitis) was occluded in its full length. Graft patency thus was 96%. In addition, two distal IMA-to-LAD anastomoses were occluded. Thus 52 (93%) of the total 56 IMA anastomoses were patent. Further, one distal IMA anastomosis was 90% stenotic, and there were three stenotic sites in the 'jump' portion, two of them 90% and the third representing a kinked area. In five of the seven patients with significant stenotic IMA-graft lesions, clinical evaluation and stress testing gave no reason to suspect myocardial ischemia. In nine of the 11 patients with positive or inconclusive clinical evaluation and stress test, the obvious cause was progression of arteriosclerosis in native vessels or angiographic defects in the vein grafts. Only two IMA grafts were angiographically defective-the one with kinking and the totally occluded graft.
Table 111. Peroperative data
Table V. Angiographic findings in sequential
surgery was mitral valve plasty in one case. Staff surgeons performed all the operations. No patient required intra-aortic balloon pumping. Postoperatively three patients underwent re-operation for bleeding and two had acute myocardial infarction. The hospital stay averaged 6 (range 3-10) days. During the observation period before follow-up investigation one patient was operated on for sternal nonunion and epigastric hernia. In another case sternal infection progressed to chronic osteomyelitis despite treatment. This patient was one of the three reoperated on for postoperative bleeding. Thorough clinical evaluation at follow-up included bicycle exercise stress testing starting at 50 W load and increasing 50 W every 4 min. Unless signs or symptoms of myocardial ischemia appeared, the cycling continued until exhaustion. Angiography was performed in all cases. If there was any suspicion of coronary ischemia, left ventriculography and selective coronary angiography were performed, studying both native vessels and grafts. In the other patients only the entire IMA, including the two anastomoses, was visualized.
RESULTS
ZMA-graBs
Data
Mean Range
Perfusion time (min) Aortic occlusion time (min) Coronary anastomoses/patient
83 51
Scand J Thoracic 26
4.1
30-140
14-77 2-6
No. of examined grafts Total occlusion Distal occlusion Graft stenosis Anastomotic stenosis
28 1 2 3 1
Sequential IMA grafting
Scand Cardiovasc J Downloaded from informahealthcare.com by Queen's University on 01/04/15 For personal use only.
DISCUSSION IMA sequential technique is used to reach more underperfused areas than with single IMAgraft. The present report is based on our first 28 patients submitted to this technically more demanding operation. The purpose was to evaluate patency of sequential IMA-grafts, especially the 'jump' portion representing the extra procedure as compared with single IMA technique. Compared with vein grafts, sequential-graft IMA has limitations in regard to the length of the IMA-graft per se and sites of anastomosis. As a rule the proximal anastomosis does not require extra length. However, it is often necessary to reach the distal LAD with the IMAgraft. The potential length of the IMA-graft as a rule makes it difficult to reach LD branches in the upper part of the LAD in combination with a distal LAD anastomosis without risk of graft kinking. Our series was small, but the early complication rate did not seem higher than in simple IMA-grafting. An exception was reoperation for bleeding (1 1 O/O). In one of these three patients bacterial mediastinitis subsequently developed, probably affecting the IMA-graft and thus linking an early complication to a poor clinical outcome, as this was the only patient with a totally occluded graft. Anghiographic evaluation in 28 (88 O/o) of our total 32 patients revealed that the intermediate patency of sequential IMA-grafts was 96% in the 'non-jump' portion and 93 O/o in the anastomoses. The distal anastomoses were most often to the LAD, as the most essential vessel involved. Distal patency in our study was 89%. Angiography showed four additional significant lesions in the distal portion, indicating optimal perfusion of 75% of the distal anastomoses. This figure is lower than for single IMA grafts and thus calls for reconsideration of the sequential technique as procedure of choice. Of the seven patients with angiographic abnormalities in sequential IMA-grafts, only two had positive or inconclusive findings at clinical
59
examination with stress testing. This lack of correlation pinpoints the importance of angiographic visualization of all IMA-grafts to reveal their true patency. Only a few authors have reported angiographic evaluation of more than 80%of their patients (2, 4). Seven (25%) of the examined patients had recurrent angina. Angiography indicated plausible causes in only two unsuccessful IMAgrafts, while in all the other cases there were defective vein grafts or significant progression of arteriosclerotic lesions in native vessels. There was no reason to suspect that any of the angiographically well functioning IMA-grafts could not provide sufficient blood flow to both recipient vessels. In introducing sequential JMA-grafting we experienced some of its technical dificuIties, indicating that this procedure should be performed only by experienced surgeons, with others taken stepwise through the learning process. Only in such circumstances does it seem feasible to increase the success rate in arterial revascularization. REFERENCES Barner HB, Standeven JW, Reese J. Twelve-year experience with internal mammary artery for coronary artery bypass. J Thorac Cardiovasc Surg 1985; 90: 668-675. Harjola PT, Frick MH, Harjula A, Jarvinen A, Meurala H, Valle M. Sequential internal mammary artery (IMA) grafts in coronary artery bypass surgery. Thorac Cardiovasc Surgeon 1984; 32: 2 88-29 2 . Lytle BW, Loop FD, Cosgrove DM, Ratliff NB, Easley K, Taylor PC. Long-term (5 to 12 years) serial studies of internal mammary artery and saphenous vein coronary bypass grafts. J Thorac Cardiovasc Surg 1985; 89: 284-258. Rankin JS, Newmann GE, Bashore T, Muhlbaier LH, Tyson GS, Ferguson TB, Reeves JG, Sabiston DC. Clinical and angiographic assessment of complex mammary grafting. J Thorac Cardiovasc Surg 1986; 92: 832-846. Singh RN, Sosa JA, Green GA. Long-term fate of the internal mammary artery and saphenous vein grafts. J Thorac Cardiovasc Surg 1983; 86:359363.
Scand J Thoracic 4'6
PATENCY OF THE INTERNAL MAMMARY ARTERY USED AS SEQUENTIAL GRAFT Jon Aksnes,' Kenneth Nordstrand,' Harald Lindberg,' Oddbjrarn Christensen,' Karleiv Vatne,*Otto Smiseth3 and Tor Froysaker' From the Departments of 'Surgery, 'Radiology and 3Medicine, Rikshospitalet, Oslo, Norway
Scand Cardiovasc J Downloaded from informahealthcare.com by Queen's University on 01/04/15 For personal use only.
(Accepted for publication July 5, 1991)
Abstract. In 28 patients with the left internal mammary artery (IMA) used as a sequential coronary artery graft, clinical and angiographic evaluation was made 19-47 months postoperatively. Patency was 96% in the proximal anastomoses and 93 Yo in all the anastomoses. Angiography, however, showed optimal function in only 75% of the distal graft ends. These observations indicate that routine use of left IMA as a sequential graft should be restricted to experienced surgeons. Clinical and angiographic findings did not always correlate, emphasizing that evaluation of IMA-graft patency should include angiography. Key words: IMA, sequential IMA-graft patency, angiography.
years. Table I presents a clinical profile. Two patients had significant left main stem stenosis. One of them was the only patient with unstable angina at the time of surgery. No patient had left ventricular aneurysm. Three patients had an isolated stenotic lesion of the left anterior descending (LAD) artery system and required only a sequential IMA graft. The others had triple vessel disease. No patient had previous heart surgery, but one had twice undergone percutaneous transluminal coronary angioplasty. The surgical technique was as earlier described (2, 4). Sequential procedure was used when the stenotic processes were localized so that two of either distal LAD, left 1st diagonal (LAD 1) or left 2nd diagonal (LD 2) required bypass. For other vessels needing bypass we used reversed saphenous vein as a single or as a sequential graft. The sites of anastomosis are listed in Table I1 and intraoperative data in Table 111. The only additional
Although the long-term patency of single internal mammary artery (IMA) grafts has proved superior to that of saphenous vein grafts (1, 3, 51, the patency of IMA as a sequential graft is not well documented angiographically. This Table I. Preoerative clinical data (28 patients) study presents both clinical and angiographic follow-up results from sequential antegrade No. of IMA-graft ing . patients Data ~~
MATERIAL AND METHODS During 20 months up to June 1989, a total of 32 patients underwent coronary artery bypass using IMA as a sequential graft. There was no hospital mortality. Two patients died at home 10 and 30 months postoperatively, one suddenly without prior symptoms of cardiac ischemia. The other patient had had myocardial infarction on postoperative day I and after discharge developed angina and dyspnea. Two survivors were not available for follow-up. One was a 36-yearold diabetic with postoperative renal failure and subsequent cerebral insult. He is now free from coronary ischemia and has received a kidney transplant. The second patient refused angiography. The study thus comprised 28 patients (only 4 women) with a mean age at operation of 59 (range 39-79)
NYHA function class I1 111 IV Left ventricular end-diastolic pressure > 25 mmHg Left ventricular ejection fraction t40% Arteriosclerosis obliterans Previous acute myocardial infarction Diabetes mellitus Hyperlipidemia Arterial hypertension
3 20 5
2 2 8 16 1
12 9
Duration of angina pectoris (years): mean 4.4, range 0.25-10. Scand J Thoracic 26
58
J. Alcsnes et al.
Table 11. Anastomoses to coronary arteries Grafts
Scand Cardiovasc J Downloaded from informahealthcare.com by Queen's University on 01/04/15 For personal use only.
IMA LAD LD 1 LD 2 Vein Simple Sequential
Table IV. Clinical data ab follow-up evaluation
No. of anastomoses
Data
26 19 11
Angina pectoris Dyspnea Fatigue NYHA function class I
I1
24 36
No. of patients 7 7 I 14
13
111
1
IV
0
The follow-up interval averaged 28 (range 19-47) months. Seven patients complained of recurrent angina. Table IV summarizes the clinical status. At exercise stress testing 17 patients had no symptoms or electrocardiographic
signs of cardiac ischemia, and thus only their IMA grafts were angiographically visualized. In the remaining 11 patients, with positive or inconclusive stress test, a full angiographic examination was performed. There were no complications of follow-up angiography. Table V shows the angiographic evaluation of the IMA grafts. Only one (in the patient with sternal osteomyelitis) was occluded in its full length. Graft patency thus was 96%. In addition, two distal IMA-to-LAD anastomoses were occluded. Thus 52 (93%) of the total 56 IMA anastomoses were patent. Further, one distal IMA anastomosis was 90% stenotic, and there were three stenotic sites in the 'jump' portion, two of them 90% and the third representing a kinked area. In five of the seven patients with significant stenotic IMA-graft lesions, clinical evaluation and stress testing gave no reason to suspect myocardial ischemia. In nine of the 11 patients with positive or inconclusive clinical evaluation and stress test, the obvious cause was progression of arteriosclerosis in native vessels or angiographic defects in the vein grafts. Only two IMA grafts were angiographically defective-the one with kinking and the totally occluded graft.
Table 111. Peroperative data
Table V. Angiographic findings in sequential
surgery was mitral valve plasty in one case. Staff surgeons performed all the operations. No patient required intra-aortic balloon pumping. Postoperatively three patients underwent re-operation for bleeding and two had acute myocardial infarction. The hospital stay averaged 6 (range 3-10) days. During the observation period before follow-up investigation one patient was operated on for sternal nonunion and epigastric hernia. In another case sternal infection progressed to chronic osteomyelitis despite treatment. This patient was one of the three reoperated on for postoperative bleeding. Thorough clinical evaluation at follow-up included bicycle exercise stress testing starting at 50 W load and increasing 50 W every 4 min. Unless signs or symptoms of myocardial ischemia appeared, the cycling continued until exhaustion. Angiography was performed in all cases. If there was any suspicion of coronary ischemia, left ventriculography and selective coronary angiography were performed, studying both native vessels and grafts. In the other patients only the entire IMA, including the two anastomoses, was visualized.
RESULTS
ZMA-graBs
Data
Mean Range
Perfusion time (min) Aortic occlusion time (min) Coronary anastomoses/patient
83 51
Scand J Thoracic 26
4.1
30-140
14-77 2-6
No. of examined grafts Total occlusion Distal occlusion Graft stenosis Anastomotic stenosis
28 1 2 3 1
Sequential IMA grafting
Scand Cardiovasc J Downloaded from informahealthcare.com by Queen's University on 01/04/15 For personal use only.
DISCUSSION IMA sequential technique is used to reach more underperfused areas than with single IMAgraft. The present report is based on our first 28 patients submitted to this technically more demanding operation. The purpose was to evaluate patency of sequential IMA-grafts, especially the 'jump' portion representing the extra procedure as compared with single IMA technique. Compared with vein grafts, sequential-graft IMA has limitations in regard to the length of the IMA-graft per se and sites of anastomosis. As a rule the proximal anastomosis does not require extra length. However, it is often necessary to reach the distal LAD with the IMAgraft. The potential length of the IMA-graft as a rule makes it difficult to reach LD branches in the upper part of the LAD in combination with a distal LAD anastomosis without risk of graft kinking. Our series was small, but the early complication rate did not seem higher than in simple IMA-grafting. An exception was reoperation for bleeding (1 1 O/O). In one of these three patients bacterial mediastinitis subsequently developed, probably affecting the IMA-graft and thus linking an early complication to a poor clinical outcome, as this was the only patient with a totally occluded graft. Anghiographic evaluation in 28 (88 O/o) of our total 32 patients revealed that the intermediate patency of sequential IMA-grafts was 96% in the 'non-jump' portion and 93 O/o in the anastomoses. The distal anastomoses were most often to the LAD, as the most essential vessel involved. Distal patency in our study was 89%. Angiography showed four additional significant lesions in the distal portion, indicating optimal perfusion of 75% of the distal anastomoses. This figure is lower than for single IMA grafts and thus calls for reconsideration of the sequential technique as procedure of choice. Of the seven patients with angiographic abnormalities in sequential IMA-grafts, only two had positive or inconclusive findings at clinical
59
examination with stress testing. This lack of correlation pinpoints the importance of angiographic visualization of all IMA-grafts to reveal their true patency. Only a few authors have reported angiographic evaluation of more than 80%of their patients (2, 4). Seven (25%) of the examined patients had recurrent angina. Angiography indicated plausible causes in only two unsuccessful IMAgrafts, while in all the other cases there were defective vein grafts or significant progression of arteriosclerotic lesions in native vessels. There was no reason to suspect that any of the angiographically well functioning IMA-grafts could not provide sufficient blood flow to both recipient vessels. In introducing sequential JMA-grafting we experienced some of its technical dificuIties, indicating that this procedure should be performed only by experienced surgeons, with others taken stepwise through the learning process. Only in such circumstances does it seem feasible to increase the success rate in arterial revascularization. REFERENCES Barner HB, Standeven JW, Reese J. Twelve-year experience with internal mammary artery for coronary artery bypass. J Thorac Cardiovasc Surg 1985; 90: 668-675. Harjola PT, Frick MH, Harjula A, Jarvinen A, Meurala H, Valle M. Sequential internal mammary artery (IMA) grafts in coronary artery bypass surgery. Thorac Cardiovasc Surgeon 1984; 32: 2 88-29 2 . Lytle BW, Loop FD, Cosgrove DM, Ratliff NB, Easley K, Taylor PC. Long-term (5 to 12 years) serial studies of internal mammary artery and saphenous vein coronary bypass grafts. J Thorac Cardiovasc Surg 1985; 89: 284-258. Rankin JS, Newmann GE, Bashore T, Muhlbaier LH, Tyson GS, Ferguson TB, Reeves JG, Sabiston DC. Clinical and angiographic assessment of complex mammary grafting. J Thorac Cardiovasc Surg 1986; 92: 832-846. Singh RN, Sosa JA, Green GA. Long-term fate of the internal mammary artery and saphenous vein grafts. J Thorac Cardiovasc Surg 1983; 86:359363.
Scand J Thoracic 4'6
