Y-Grafts and Sequential
Grafts in C o r o n e Bypass Surgery: A Critical Evaluation of Patency Rates Thomas J. Yeh, M.D., Dariush Heidary, M.D., and Larry Shelton, C.C.P. ABSTRACT In a series of 584 patients undergoing coronary bypass, 425 patients received Y-grafts, sequential grafts, or a combination of the two. The saphenous veins from the legs frequently had Y- or double Y-branches suitable for bypasses. As many as 5 grafts have been served satisfactorily by a single proximal anastomosis. Simultaneous procedures included 45 left ventricular aneurysmectomies, 18 valve replacements, 7 carotid endarterectomies, repairs of a ventricular septal defect, an acute dissection, and coronary arteriovenous fistulas, with a total surgical mortality of 6 (1.4%). Restudy to determine graft patency was undertaken only in the 59 patients with unsatisfactory surgical results. These patients represent the worst 10% of the series in terms of surgical results. The patency rate for proximal anastomoses was 93%; Y-branchings, 93%; distal end-to-side anastomoses, 89%; and distal side-to-side anastomoses, 89%. Fifty-eight patients (98%) had at least 1 patent graft, and in 47 patients (80%) all anastomoses were patent up to six years after operation. Six patients underwent reoperation without any deaths.
Y-grafts offer most of the advantages of sequential grafts with few of the disadvantages.
Material and Method In a series of 584 consecutive patients who had aortocoronary bypass operations, 425 received Y-grafts, sequential grafts, or a combination of the two. Approximately 20% of the patients underwent operation on an urgent or emergency basis because of unstable angina, stenosis of the left main coronary artery, or its equivalent. Concomitant procedures were required in 76 (18%) of the 425 patients and included 45 left ventricular aneurysmectomies (1lo/o), 18 valve replacements (4%), 7 carotid endarterectomies, repairs of a ventricular septal defect, an acute aortic dissection, coronary arteriovenous fistulas, and an innominate artery bypass. A restudy to determine graft patency was recommended only for patients in whom surgical results were unsatisfactory as judged by the cardiologist. Fifty-nine patients were restudied one month to six years following bypass proceDuring the seven-year period 1971 to 1978, Y- dure. The patency rates of various anastomoses grafts and sequential grafts were employed ex- were calculated from the data obtained on these tensively in aortocoronary bypasses. Several 59 patients. authors have reported on the advantages of sequential grafts and the patency rates of the Technical Considerations side-to-side anastomosis [l-3, 5, 7, 91. Rela- The saphenous vein was harvested from the tively little has been written about Y-grafts ankle up toward the knee. Thigh veins were [5, 6, 91. Naturally formed Y-branches in the seldom used. Naturally formed Y-branches saphenous vein have been found to be frequent were found in the legs in more than 50% of occurrences. To our knowledge, their use in the patients. Occasionally two or three such coronary bypass grafts has not been reported. branches are found in one vein. A 2 cm length of a branch is adequate for a bypass. When YFrom the Memorial Medical Center, Savannah, GA. branches could not be found, sequential grafts Presented at the Twenty-fifth Annual Meeting of the Southe m Thoracic Surgical Association, Nov 2-4, 1978, Marco were used. Incision in the vein for side-to-side Island, FL. anastomosis was always made longitudinally to Address reprint requests to Dr. Yeh, Cardiovascular and Thoracic Surgery Associates, PC, 5112 Paulsen St, Savan- avoid constriction at the anastomotic site [4]. nah, GA 31405. The angle of crossing between the vein graft 409
0003-4975179/050409-04$01.25 @ 1978 by Thomas J. Yeh
410 The Annals of Thoracic Surgery Vol 27 No 5 May 1979
Aortocoronary quadruple and quintuple bypasses using Y-grafts, sequential grafts, or a combination of the t w o . (lad = left anterior descending coronary artery; m , = first marginal artery; m:, = third marginal artery; d = diagonal artery; rpd = right posterior descending artery; im = intermediate artery; r = right coronary artery; d, = first diagonal artery; d, = second diagonal artery.)
and the artery ranges from parallel to a right angle. In both Y- and sequential grafts, care was taken to avoid angulation, tension, and twisting of the vein grafts. Correct anatomical re-
lationship between the artery and vein was judged with the vein distended. For a proximal anastomosis, a small ellipse of tissue was removed from the aortic wall. In some patients, a single proximal anastomosis served 4 to 5 distal anastomoses. The Figure depicts some representative arrangements.
Results The average number of grafts was 3.29 per patient. The relationship between the number of
411 Yeh, Heidary, and Shelton: Y-Grafts and Sequential Grafts in Coronary Bypasses
Table 1 . Number of Patients According to the Number of Proximal and Distal Anastomoses No. of Proximal
No. of Distal Anastomoses
Anastomoses
Double
Triple
Single Double Triple Total
82
59 137
82
196
patients and the proximal and distal anastomoses is shown in Table 1. Among the 425 patients in whom Y-grafts, sequential grafts, or both were used, there were 6 deaths, an overall mortality rate of 1.4%. Two of the deaths occurred in salvage patients in whom extensive generalized atherosclerosis involved the carotid, peripheral, and renal arteries. Another patient had replacement of a mitral valve, resection of two separate left ventricular aneurysms, and triple bypass grafts all in one session. One patient was operated on during an acute infarction. The other 2 deaths were in patients with no additional factors to make them high-risk patients. It was found that the greater the number of grafts a patient received the less likely he was to need a restudy. Whereas the restudy rate for the patients receiving single or double bypasses was 12.570, it was 9.3% for the patients with triple bypass grafts and 7% for those receiving 4 or 5 grafts. In the 59 patients restudied, there were 102 proximal and 158 distal anastomoses. Of the distal anastomoses, 130 were end-to-side and 28 were side-to-side. Endarterectomy was done in 14 of 130 end-to-side anastomoses. The patency rates for the various types of anastomosis are tabulated in Table 2. Endarterectomy predisposed to a lower patency rate, 64% compared with 92% when endarterectomy was not employed. For the patients operated on since 1974, the patency rate was 91% compared with 85% for those done before 1973. The difference is explained almost totally by elimination of endarterectomy in the latter group. The duration of time between operation and restudy did not influence the patency rates to any extent (Table 3). Of 59 patients restudied, 47 (79.7%) were
Quadruple
Quintuple
Subtotal
16 94 3
4 30
161 261 3
113
34
425
Table 2 . Patency Rates of Various Anastomoses in 59 Patients Restudied
Anastomosis Proximal Distal
Total No.
No.
102 158
7 17
End-to-side Side-to-side Y-branching
Occluded
130 28 29
Patency Rate ("/o)
93 89 14 3
89 89
2
93
Table 3. Patency Rate versus Age of Grafts" W h e n Restudied Age
No. of
No. of Grafts
Patency
Rate Occluded (%)
(Yd
Patients
0- 1 1-2 2-3 3-4 4-5 5-6
24 13 8 4 6 4
73 27 18 7 9 10
8 0 2 0 1 1
59
144
12
~~~~~
Total
89 100 89 100 89 90 91.6
"Excluding14 anastomoses with thromboendarterectomy.
found to have all grafts patent, and 58 patients (98.3%) had some functioning grafts. In 1 patient all grafts were found to be closed. Reoperation was carried out in 6 patients (10% of restudy group, 1% of total series) without a death.
Comment Each Y-branch or side-to-side anastomosis used translates into one less proximal anastomosis, with a reduction of 10 to 15 minutes of the pump and operating times and a saving of
412 The Annals of Thoracic Surgery Vol 27
No 5 May 1979
up to 10 cm of the segment used for the vein graft. The theoretical disadvantage of a sequential graft is that an occlusion of a proximal anastomosis can result in the closure of all the distal anastomoses. In practice, the proximal anastomosis as the primary site of graft closure has been rare, and since it became our routine to excise an ellipse of tissue from the aortic wall for anastomosis, this problem has been eliminated. In 1 patient in whom the proximal segment of the vein became occluded, the distal vein segment between the 2 distal anastomoses remained patent. At reoperation, a new bypass was inserted into this bridge of vein. The Ygrafts have an additional advantage over sequential grafts in that none of the theoretical objections to side-to-side anastomosis applies. Naturally formed Y-branching is hemodynamically sound. Analysis of Table 2 indicates that most of the graft failures occur during the first year. A longer follow-up showed no further decrease in patency rate. The figures also indicate that in most cases, the persistence or recurrence of symptoms cannot be attributed to graft closure, but rather to the development of new lesions or progression of preexisting mild lesions. This conclusion is in agreement with the findings of Seides and co-workers [81. After our study, we reached the following conclusions: 1. In 59 patients in whom restudy was done for unsatisfactory results from aortocoronary bypass, 89% of the grafts were found to be patent. Fifty-eight patients (98%) had some functioning grafts, and 47 patients (80%) had all grafts patent. 2 . Side-to-side anastomosis has the same patency rate as end-to-side anastomosis. 3. Naturally formed Y-branching suitable for
bypass can be found in the saphenous veins in the leg in more than 50% of patients. 4. Proximal anastomosis and Y-branching is seldom the primary site of graft closure. As many as 5 distal anastomoses can be served by a single proximal anastomosis. 5. Unsatisfactory surgical results are not due to graft closures, as a rule. The causes must be looked for elsewhere and include progression of mild lesions, development of new lesions, previously damaged left ventricle, postpericardiotomy syndrome, musculoskeletal pains, or neurotic complaints.
References 1. Bartley TD, Bigelow JC, Page US: Aortocoronary
2.
3.
4.
5. 6. 7. 8.
9.
bypass grafting with multiple sequential anastomoses to a single vein. Arch Surg 105:915, 1972 Bigelow JC, Bartley TD, Page US, et al: Long-term follow-up of sequential aortocoronary venous grafts. Ann Thorac Surg 22:507, 1976 Grondin CM, Limet R: Sequential anastomoses in coronary artery grafting: technical aspect and early and late angiographic results. Ann Thorac Surg 23:1, 1977 Grow JB, Brantigan CO: The diamond anastomosis: a technique for creating a right-angle side-to-side vascular anastomosis. J Thorac Cardiovasc Surg 69:188, 1975 Loop FD: Sequential coronary artery anastomoses (editorial). Ann Thorac Surg 17:637, 1974 Marco JD, Orszulak TL, Barner HB, et al: In favor of the Y-graft for aortocoronary bypass. Ann Thorac Surg 21:519, 1976 Moreno-Cabral RJ, Mamiya RT, Dang CR: Multiple coronary artery bypass using sequential technique. Am J Surg 134:64, 1977 Seides SF, Borer JS, Kent KM, et al: Long term anatomic fate of coronary artery bypass grafts and functional status of patients five years after operation. N Engl J Med 298:1213, 1978 Sewell WH: Improved coronary vein graft patency rates with side-to-side anastomoses. Ann Thorac Surg 17:538, 1974
Grafts in C o r o n e Bypass Surgery: A Critical Evaluation of Patency Rates Thomas J. Yeh, M.D., Dariush Heidary, M.D., and Larry Shelton, C.C.P. ABSTRACT In a series of 584 patients undergoing coronary bypass, 425 patients received Y-grafts, sequential grafts, or a combination of the two. The saphenous veins from the legs frequently had Y- or double Y-branches suitable for bypasses. As many as 5 grafts have been served satisfactorily by a single proximal anastomosis. Simultaneous procedures included 45 left ventricular aneurysmectomies, 18 valve replacements, 7 carotid endarterectomies, repairs of a ventricular septal defect, an acute dissection, and coronary arteriovenous fistulas, with a total surgical mortality of 6 (1.4%). Restudy to determine graft patency was undertaken only in the 59 patients with unsatisfactory surgical results. These patients represent the worst 10% of the series in terms of surgical results. The patency rate for proximal anastomoses was 93%; Y-branchings, 93%; distal end-to-side anastomoses, 89%; and distal side-to-side anastomoses, 89%. Fifty-eight patients (98%) had at least 1 patent graft, and in 47 patients (80%) all anastomoses were patent up to six years after operation. Six patients underwent reoperation without any deaths.
Y-grafts offer most of the advantages of sequential grafts with few of the disadvantages.
Material and Method In a series of 584 consecutive patients who had aortocoronary bypass operations, 425 received Y-grafts, sequential grafts, or a combination of the two. Approximately 20% of the patients underwent operation on an urgent or emergency basis because of unstable angina, stenosis of the left main coronary artery, or its equivalent. Concomitant procedures were required in 76 (18%) of the 425 patients and included 45 left ventricular aneurysmectomies (1lo/o), 18 valve replacements (4%), 7 carotid endarterectomies, repairs of a ventricular septal defect, an acute aortic dissection, coronary arteriovenous fistulas, and an innominate artery bypass. A restudy to determine graft patency was recommended only for patients in whom surgical results were unsatisfactory as judged by the cardiologist. Fifty-nine patients were restudied one month to six years following bypass proceDuring the seven-year period 1971 to 1978, Y- dure. The patency rates of various anastomoses grafts and sequential grafts were employed ex- were calculated from the data obtained on these tensively in aortocoronary bypasses. Several 59 patients. authors have reported on the advantages of sequential grafts and the patency rates of the Technical Considerations side-to-side anastomosis [l-3, 5, 7, 91. Rela- The saphenous vein was harvested from the tively little has been written about Y-grafts ankle up toward the knee. Thigh veins were [5, 6, 91. Naturally formed Y-branches in the seldom used. Naturally formed Y-branches saphenous vein have been found to be frequent were found in the legs in more than 50% of occurrences. To our knowledge, their use in the patients. Occasionally two or three such coronary bypass grafts has not been reported. branches are found in one vein. A 2 cm length of a branch is adequate for a bypass. When YFrom the Memorial Medical Center, Savannah, GA. branches could not be found, sequential grafts Presented at the Twenty-fifth Annual Meeting of the Southe m Thoracic Surgical Association, Nov 2-4, 1978, Marco were used. Incision in the vein for side-to-side Island, FL. anastomosis was always made longitudinally to Address reprint requests to Dr. Yeh, Cardiovascular and Thoracic Surgery Associates, PC, 5112 Paulsen St, Savan- avoid constriction at the anastomotic site [4]. nah, GA 31405. The angle of crossing between the vein graft 409
0003-4975179/050409-04$01.25 @ 1978 by Thomas J. Yeh
410 The Annals of Thoracic Surgery Vol 27 No 5 May 1979
Aortocoronary quadruple and quintuple bypasses using Y-grafts, sequential grafts, or a combination of the t w o . (lad = left anterior descending coronary artery; m , = first marginal artery; m:, = third marginal artery; d = diagonal artery; rpd = right posterior descending artery; im = intermediate artery; r = right coronary artery; d, = first diagonal artery; d, = second diagonal artery.)
and the artery ranges from parallel to a right angle. In both Y- and sequential grafts, care was taken to avoid angulation, tension, and twisting of the vein grafts. Correct anatomical re-
lationship between the artery and vein was judged with the vein distended. For a proximal anastomosis, a small ellipse of tissue was removed from the aortic wall. In some patients, a single proximal anastomosis served 4 to 5 distal anastomoses. The Figure depicts some representative arrangements.
Results The average number of grafts was 3.29 per patient. The relationship between the number of
411 Yeh, Heidary, and Shelton: Y-Grafts and Sequential Grafts in Coronary Bypasses
Table 1 . Number of Patients According to the Number of Proximal and Distal Anastomoses No. of Proximal
No. of Distal Anastomoses
Anastomoses
Double
Triple
Single Double Triple Total
82
59 137
82
196
patients and the proximal and distal anastomoses is shown in Table 1. Among the 425 patients in whom Y-grafts, sequential grafts, or both were used, there were 6 deaths, an overall mortality rate of 1.4%. Two of the deaths occurred in salvage patients in whom extensive generalized atherosclerosis involved the carotid, peripheral, and renal arteries. Another patient had replacement of a mitral valve, resection of two separate left ventricular aneurysms, and triple bypass grafts all in one session. One patient was operated on during an acute infarction. The other 2 deaths were in patients with no additional factors to make them high-risk patients. It was found that the greater the number of grafts a patient received the less likely he was to need a restudy. Whereas the restudy rate for the patients receiving single or double bypasses was 12.570, it was 9.3% for the patients with triple bypass grafts and 7% for those receiving 4 or 5 grafts. In the 59 patients restudied, there were 102 proximal and 158 distal anastomoses. Of the distal anastomoses, 130 were end-to-side and 28 were side-to-side. Endarterectomy was done in 14 of 130 end-to-side anastomoses. The patency rates for the various types of anastomosis are tabulated in Table 2. Endarterectomy predisposed to a lower patency rate, 64% compared with 92% when endarterectomy was not employed. For the patients operated on since 1974, the patency rate was 91% compared with 85% for those done before 1973. The difference is explained almost totally by elimination of endarterectomy in the latter group. The duration of time between operation and restudy did not influence the patency rates to any extent (Table 3). Of 59 patients restudied, 47 (79.7%) were
Quadruple
Quintuple
Subtotal
16 94 3
4 30
161 261 3
113
34
425
Table 2 . Patency Rates of Various Anastomoses in 59 Patients Restudied
Anastomosis Proximal Distal
Total No.
No.
102 158
7 17
End-to-side Side-to-side Y-branching
Occluded
130 28 29
Patency Rate ("/o)
93 89 14 3
89 89
2
93
Table 3. Patency Rate versus Age of Grafts" W h e n Restudied Age
No. of
No. of Grafts
Patency
Rate Occluded (%)
(Yd
Patients
0- 1 1-2 2-3 3-4 4-5 5-6
24 13 8 4 6 4
73 27 18 7 9 10
8 0 2 0 1 1
59
144
12
~~~~~
Total
89 100 89 100 89 90 91.6
"Excluding14 anastomoses with thromboendarterectomy.
found to have all grafts patent, and 58 patients (98.3%) had some functioning grafts. In 1 patient all grafts were found to be closed. Reoperation was carried out in 6 patients (10% of restudy group, 1% of total series) without a death.
Comment Each Y-branch or side-to-side anastomosis used translates into one less proximal anastomosis, with a reduction of 10 to 15 minutes of the pump and operating times and a saving of
412 The Annals of Thoracic Surgery Vol 27
No 5 May 1979
up to 10 cm of the segment used for the vein graft. The theoretical disadvantage of a sequential graft is that an occlusion of a proximal anastomosis can result in the closure of all the distal anastomoses. In practice, the proximal anastomosis as the primary site of graft closure has been rare, and since it became our routine to excise an ellipse of tissue from the aortic wall for anastomosis, this problem has been eliminated. In 1 patient in whom the proximal segment of the vein became occluded, the distal vein segment between the 2 distal anastomoses remained patent. At reoperation, a new bypass was inserted into this bridge of vein. The Ygrafts have an additional advantage over sequential grafts in that none of the theoretical objections to side-to-side anastomosis applies. Naturally formed Y-branching is hemodynamically sound. Analysis of Table 2 indicates that most of the graft failures occur during the first year. A longer follow-up showed no further decrease in patency rate. The figures also indicate that in most cases, the persistence or recurrence of symptoms cannot be attributed to graft closure, but rather to the development of new lesions or progression of preexisting mild lesions. This conclusion is in agreement with the findings of Seides and co-workers [81. After our study, we reached the following conclusions: 1. In 59 patients in whom restudy was done for unsatisfactory results from aortocoronary bypass, 89% of the grafts were found to be patent. Fifty-eight patients (98%) had some functioning grafts, and 47 patients (80%) had all grafts patent. 2 . Side-to-side anastomosis has the same patency rate as end-to-side anastomosis. 3. Naturally formed Y-branching suitable for
bypass can be found in the saphenous veins in the leg in more than 50% of patients. 4. Proximal anastomosis and Y-branching is seldom the primary site of graft closure. As many as 5 distal anastomoses can be served by a single proximal anastomosis. 5. Unsatisfactory surgical results are not due to graft closures, as a rule. The causes must be looked for elsewhere and include progression of mild lesions, development of new lesions, previously damaged left ventricle, postpericardiotomy syndrome, musculoskeletal pains, or neurotic complaints.
References 1. Bartley TD, Bigelow JC, Page US: Aortocoronary
2.
3.
4.
5. 6. 7. 8.
9.
bypass grafting with multiple sequential anastomoses to a single vein. Arch Surg 105:915, 1972 Bigelow JC, Bartley TD, Page US, et al: Long-term follow-up of sequential aortocoronary venous grafts. Ann Thorac Surg 22:507, 1976 Grondin CM, Limet R: Sequential anastomoses in coronary artery grafting: technical aspect and early and late angiographic results. Ann Thorac Surg 23:1, 1977 Grow JB, Brantigan CO: The diamond anastomosis: a technique for creating a right-angle side-to-side vascular anastomosis. J Thorac Cardiovasc Surg 69:188, 1975 Loop FD: Sequential coronary artery anastomoses (editorial). Ann Thorac Surg 17:637, 1974 Marco JD, Orszulak TL, Barner HB, et al: In favor of the Y-graft for aortocoronary bypass. Ann Thorac Surg 21:519, 1976 Moreno-Cabral RJ, Mamiya RT, Dang CR: Multiple coronary artery bypass using sequential technique. Am J Surg 134:64, 1977 Seides SF, Borer JS, Kent KM, et al: Long term anatomic fate of coronary artery bypass grafts and functional status of patients five years after operation. N Engl J Med 298:1213, 1978 Sewell WH: Improved coronary vein graft patency rates with side-to-side anastomoses. Ann Thorac Surg 17:538, 1974
