In situ bilateral skeletonized internal thoracic arterial grafting for left-side myocardial revascularization using an off-pump technique
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《血管的通路杂志》
a Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka City, 545-8585, Japan
b Department of Cardiovascular Surgery, Sakakibara Heart Institute, Tokyo, Japan
c Department of Cardiovascular Surgery, Shin-Tokyo Hospital, Chiba, Japan
Abstract
The aim of this study was to review the clinical and angiographic outcomes of in situ skeletonized bilateral internal thoracic artery (ITA) grafting for left coronary arterial revascularization using an off-pump technique in 144 consecutive patients. We also assessed the difference between left and right ITA grafting to the left anterior descending coronary artery (LAD). Arrangement of the bilateral ITAs (grafting of the left/right ITA to the LAD) was decided according to the coronary anatomy and quality of the grafts. Early postoperative angiograms were evaluated in 110 patients. The average numbers of anastomoses and bilateral ITA anastomoses per patient were 3.4 and 2.3, respectively. There were no surgical deaths or sternal infection. The left and right ITA were anastomosed to the LAD in 106 (73.6%) and 38 (26.4%) patients, respectively. There were no differences in preoperative conditions and postoperative complications between the left ITA and right ITA to LAD groups. The patencies of the left and right ITAs were 99.1 and 100%, respectively. In situ skeletonized bilateral ITA grafting for left-side revascularization using an off-pump technique was shown to be feasible, producing excellent early clinical and angiographic outcomes. Furthermore, arrangement of bilateral ITAs did not affect outcomes.
Key Words: Coronary artery bypass grafts; Coronary artery bypass grafting; Off-pump coronary artery bypass grafting
1. Introduction
Left internal thoracic artery (ITA) grafting has been shown to have better long-term patency rate and excellent clinical results compared to saphenous vein grafts [1]. Furthermore, better long-term outcomes have been demonstrated with bilateral ITA grafting compared to single ITA graft [2,3]. Especially, long-term benefits may be achieved when in situ bilateral ITAs are used for left-side myocardial revascularization [4]. Since the length and flexibility of ITAs are increased if they are harvested with a skeletonized technique, some reports have described the use of such grafts for multiple grafting [5]. However, there is still some reluctance to use bilateral ITAs because of technical difficulty, the prolonged operation time and increased chance of sternal infection.
Off-pump coronary artery bypass grafting (OPCAB) provides early and long-term benefits compared with conventional coronary artery bypass grafting (CABG) [6,7]. However, few studies have determined the optimum combination of OPCAB and in situ bilateral ITA grafting [7,8], and there remain concerns over the quality and patency of grafts when these techniques are combined.
This study aims to determine the early clinical and angiographic outcomes of using in situ bilateral skeletonized ITAs for multiple left coronary artery bypass grafting in patients undergoing OPCAB. We also assess the difference between left and right ITA grafting to the left anterior descending coronary artery (LAD).
2. Patients and methods
2.1. Patient population
Between April 2001 and July 2004, we performed isolated OPCAB in 602 patients at Shin-Tokyo Hospital. Of these, 336 patients (55.8%) received bilateral ITA grafts for myocardial revascularization, and of these, there were 144 (60.8%) whose bilateral ITAs were used as in situ grafts. In these patients, ITAs were not used as the inflow for the free grafts. Preoperative characteristics are summarized in Table 1. Diabetes, obesity, female gender and chronic obstructive pulmonary disease were not considered contra-indications of the need to harvest a bilateral ITA.
This study was approved by our institutional review committee, and informed consent was obtained from all patients with respect to the surgical method and postoperative angiography.
2.2. ITA harvesting
All ITAs were harvested in a skeletonized fashion using an ultrasonic scalpel. Radial arteries, gastroepiploic arteries and saphenous vein grafts were harvested in 55 patients (38.2%), 44 patients (30.6%) and 31 patients (21.5%), respectively (Table 2). Heparin was administered after all grafts were harvested.
2.3. Grafting of bilateral ITA
CABG strategy was to bypass all significant stenosis (a diameter reduction of at least 50%) in all coronary vessels larger than 1 mm in diameter. Since the long-term result of bilateral ITAs used for left coronary artery has been proved to be better than that used for right coronary artery (RCA) [4], we did not use the ITA for RCA. Arrangement of the ITAs, which ITA was used for the LAD and which ITA was used for the circumflex artery (Cx), was decided according to the coronary anatomy and quality of the graft, including its length. When the left/right ITA was used for the LAD, the right/left ITA was used for Cx revascularization. The choice and combination of other grafts were based on the coronary artery anatomy, severity of coronary stenosis, and size of the grafted vessel. Basically, the larger ITA was used for the LAD. When sequential grafting is necessary in the Cx, the longer ITA will be used for this region.
2.4. Surgical technique
Median sternotomy was performed in all patients. A deep pericardial stay suture was not used, and a commercially available heart positioner and stabilizer were applied to the heart (Starfish and Octopus, Medtronic Inc., Minneapolis, MN). A bloodless field was obtained using a proximal silastic snare suture and CO2 blower. All anastomoses were performed with an 8-0 polypropylene running suture.
When the right ITA was anastomosed to the Cx, it was routed through the transverse sinus. After the harvesting the right ITA, the distal end of the graft was clipped with silastic tape without twisting. A right-angled forceps was used to grasp the tape and pass the graft through the transverse sinus. When sequential grafting is constructed, diamond shaped side-to-side anastomosis and terminal T-shaped anastomosis are our preferred approaches [9]. When the right ITA was anastomosed to the LAD, it was directed anterior to the aorta. When possible, the right ITA was wrapped in thymic tissue and covered with mediastinal fat to prevent injury at reopening [10].
2.5. Angiographic study
Postoperative angiography was performed before discharge at 4 to 11 days (mean: 7.8±1.9 days) after surgery to assess graft patency in 110 patients (76.4%) who gave informed consent. Clinical and angiographic outcomes were then compared between those in whom the left ITA was grafted to the LAD and right ITA was grafted to the Cx (left ITA to LAD group) and vice versa (right ITA to LAD group).
2.6. Statistical analysis
Continuous variables are reported as the mean ± standard deviation. Continuous variables were compared using the Student's t-test and discrete variables were compared using the 2-test or Fisher's exact test. Differences were considered statistically significant at P<0.05. Statistical analyses were performed using the StatView 5.0 software package (SAS Institute Inc, Cary, NC).
3. Results
The average number of anastomoses per patient was 3.4±1.0 (range: 2–7) and the average number of bilateral ITA anastomoses was 2.3±0.5 (range: 2–4) (Table 2). The mean number of grafts per patient was 2.9±0.6. Bilateral ITA grafts only were used in 34 patients.
There were no surgical deaths (defined as death within 30 days after surgery); other morbidities are listed in Table 3. Re-exploration due to side-branch bleeding of the ITAs was not performed in any patients. Postoperative respiratory failure (defined as prolonged ventilator use for more than 48 h after surgery) was observed in three patients (2.1%). No sternal infection, superficial or deep, was observed.
3.1. Arrangement of ITAs
The left ITA was anastomosed to the LAD in 106 patients (73.6%) and the right ITA was anastomosed to the LAD in 38 patients (26.4%). Graft arrangement of the bilateral ITAs in these patients is listed in Table 4. The preoperative characteristics of the two groups did not differ (Table 1). The total number of anastomoses per patient in the left ITA to LAD group (3.5±1.0) was larger than that in the right ITA to LAD group (3.2±1.0); however, this difference did not reach statistical significance (Table 2). There were no differences in the number of bilateral ITA anastomoses per patient between the two groups (2.2±0.5 vs. 2.3±0.6). Although the number of grafts per patient was not different between groups, the radial artery was more frequently used in the left ITA to LAD group than the right ITA to LAD group (45.3% vs. 18.4%). There was no difference in postoperative complications and courses between the two groups (Table 3).
3.2. Angiographic results
The patency rate of the left ITA was 99.1% (109/110) and that of the right ITA was 100% (110/110). Only one ITA graft to the LAD was occluded. No stenosis of the right ITA due to compression by the aorta or kinking was observed in any patient. The patency rates of the radial arteries, the gastroepiploic arteries and saphenous vein grafts were 93.6% (44/47), 86.2% (25/29) and 100% (21/21), respectively.
4. Discussion
Bilateral ITA coronary artery bypass grafting has been shown to result in better survival than single ITA grafting [2,3]. Composite grafting using free ITA has been shown to result in a decreased midterm survival compared to in situ bilateral ITA grafting [10]. Especially, long-term benefits may be achieved when in situ bilateral ITAs are used for left-side myocardial revascularization [4]. It is possible to evaluate the outcomes of in situ ITA grafting from the angiographic results, because no ITA was used as an inflow graft in this study. The early clinical and angiographic results in our patients are excellent and comparable to those obtained in other studies using bilateral skeletonized ITAs [7,8]. These favorable results reveal the effectiveness and safety of the in situ bilateral ITA grafting for the left myocardial revascularization with off-pump technique.
There are two arrangements of the bilateral ITA grafting in left-side myocardial revascularization. One is anastomosis of the left ITA to the LAD and the right ITA to the Cx, and the other is anastomosis of the right ITA to the LAD and the left ITA to the Cx. The superiority of one of these two arrangements has never been determined. The first arrangement (left ITA to LAD) was employed in 73.6% of patients in the present study. Although it was easy to achieve these operative procedures, this arrangement has several limitations. The first is the length of the right ITA, which could sometimes not reach two or three lateral branches sequentially. The second is the course of the right ITA: a retroaortic course is disadvantageous because of the inability to control side-branch bleeding, compression by the aorta or undetected graft kinks. However, in our patients, no side-branch bleeding, stenosis or kinks were observed in postoperative angiography.
The second arrangement (right ITA to LAD) was used in 26.4% of patients under the assumption that the patency rates of both arrangements were identical [11]. Sequential grafting of the left ITA to the Cx was also easily performed. However, this arrangement also has a limitation. There is a compromise of surgical flexibility by anastomosing the right ITA in its distal and relative narrow part to the LAD. Since there were no differences in clinical and angiographic outcomes between these two arrangements in the present study, we suggest that arrangement should be decided upon according to the quality of the grafts and anatomy of the target vessels. We basically use the larger ITA for the LAD. When sequential grafting is necessary in the Cx region, the longer ITA will be used for this region.
The combination of OPCAB and arterial grafts is widespread [9,12]. Though sequential grafting using bilateral ITAs is somewhat technically demanding with a beating heart, the distance between the two anastomoses can be determined easily with the OPCAB technique [9]. In the present study, the average number of bilateral ITA anastomoses per patient was 2.3±0.5. As shown in the results, sequential grafting can be performed safely using either the left or right ITA with the off-pump technique. We believe that determining the correct direction and course of the conduit are important in preventing kinking, especially kinking of the right ITA through the transverse sinus.
A skeletonized ITA provides a longer length and better flexibility than a pedicled ITA [5]. Moreover, the blood flow of skeletonized ITA is reported to be greater than that of pedicled ITA [13]. As a result, grafting to a beating heart can be easily performed with skeletonized ITAs. Furthermore, with the skeletonization technique, the utilization of bilateral ITAs might no longer be a risk factor for mediastinitis, because the collateral blood supply to the sternum can be preserved [14,15]. In the present study, no sternal infection, superficial or deep, was observed using these techniques, although there was no selection bias for using bilateral ITAs.
The operation time in the present study may have been long with nearly 5 h. This may be because all grafts were harvested by residents in our institutes. Furthermore, the harvesting of the bilateral ITAs may take a longer time than harvesting a single ITA. However, we believe that in situ bilateral skeletonized with OPCAB is a safe method with least complication rate even though it relatively took a long time.
The present clinical study had the following limitations. The number of patients included was small and only early clinical and angiographic results were obtained. Furthermore, this was a retrospective observational study and not randomized. Lastly, because there was no control group, it is not possible to conclude that in situ bilateral skeletonized ITA grafting with OPCAB is superior to conventional CABG.
In conclusion, we demonstrated the feasibility of in situ bilateral skeletonized ITA grafts for left-side myocardial revascularization using the off-pump technique, revealing excellent early clinical and angiographic results. Moreover, arrangement of the bilateral ITA did not affect the results.
References
Cameron A, Davis KB, Green G, Schaff HV. Coronary bypass surgery with internal-thoracic-artery grafts – effects on survival over a 15-year period. N Engl J Med 1996; 334:216–219.
Rizzoli G, Schiavon L, Bellini P. Does the use of bilateral internal mammary artery (IMA) grafts provide incremental benefit relative to the use of a single IMA graft A meta-analysis approach. Eur J Cardiothorac Surg 2002; 22:781–786.
Calafiore AM, Di Giammarco G, Teodori G, Di Mauro M, Iaco AL, Bivona A, Contini M, Vitolla G. Late results of first myocardial revascularization in multiple vessel disease: single versus bilateral internal mammary artery with or without saphenous vein grafts. Eur J Cardiothorac Surg 2004; 26:542–548.
Schmidt SE, Jones JW, Thornby JI, Miller CC 3rd, Beall AC Jr. Improved survival with multiple left-sided bilateral internal thoracic artery grafts. Ann Thorac Surg 1997; 64:9–14.
Gurevitch J, Paz Y, Shapira I, Matsa M, Kramer A, Pevni D, Lev-Ran O, Moshkovitz Y, Mohr R. Routine use of bilateral skeletonized internal mammary arteries for myocardial revascularization. Ann Thorac Surg 1999; 68:406–411.
Sabik JF, Blackstone EH, Lytle BW, Houghtaling PL, Gillinov AM, Cosgrove DM. Equivalent midterm outcomes after off-pump and on-pump coronary surgery. J Thorac Cardiovasc Surg 2004; 127:142–148.
Calafiore AM, Di Giammarco G, Teodori G, Iaco AL, Pano M, Contini M, Vitolla G, Di Mauro M. Bilateral internal thoracic artery grafting with and without cardiopulmonary bypass: six-year clinical outcome. J Thorac Cardiovasc Surg 2005; 130:340–345.
Kim KB, Cho KR, Chang WI, Lim C, Ham BM, Kim YL. Bilateral skeletonized internal thoracic artery graftings in off-pump coronary artery bypass: early result of Y versus in situ grafts. Ann Thorac Surg 2002; 74:S1371–1376.
Fukui T, Takanashi S, Hosoda Y, Suehiro S. Total arterial myocardial revascularization using composite and sequential grafting with the off-pump technique. Ann Thorac Surg 2005; 80:579–585.
Lev-Ran O, Paz Y, Pevni D, Kramer A, Shapira I, Locker C, Mohr R. Bilateral internal thoracic artery grafting: midterm results of composite versus in situ crossover graft. Ann Thorac Surg 2002; 74:704–710.
Chow MS, Sim E, Orszulak TA, Schaff HV. Patency of internal thoracic artery grafts: comparison of right versus left and importance of vessel grafted. Circulation 1994; 90:Pt 2II129–132.
Quigley RL, Weiss SJ, Highbloom RY, Pym J. Creative arterial bypass grafting can be performed on the beating heart. Ann Thorac Surg 2001; 72:793–797.
Choi JB, Lee SY. Skeletonized and pedicled internal thoracic artery grafts: effect on free flow during bypass. Ann Thorac Surg 1996; 61:909–913.
Parish MA, Asai T, Grossi EA, Esposito R, Galloway AC, Colvin SB, Spencer FC. The effects of different techniques of internal mammary artery harvesting on sternal blood flow. J Thorac Cardiovasc Surg 1992; 104:1303–1307.
Higami T, Maruo A, Yamashita T, Shida T, Ogawa K. Histologic and physiologic evaluation of skeletonized internal thoracic artery harvesting with an ultrasonic scalpel. J Thorac Cardiovasc Surg 2000; 120:1142–1147.(Toshihiro Fukui, Shuichir)
b Department of Cardiovascular Surgery, Sakakibara Heart Institute, Tokyo, Japan
c Department of Cardiovascular Surgery, Shin-Tokyo Hospital, Chiba, Japan
Abstract
The aim of this study was to review the clinical and angiographic outcomes of in situ skeletonized bilateral internal thoracic artery (ITA) grafting for left coronary arterial revascularization using an off-pump technique in 144 consecutive patients. We also assessed the difference between left and right ITA grafting to the left anterior descending coronary artery (LAD). Arrangement of the bilateral ITAs (grafting of the left/right ITA to the LAD) was decided according to the coronary anatomy and quality of the grafts. Early postoperative angiograms were evaluated in 110 patients. The average numbers of anastomoses and bilateral ITA anastomoses per patient were 3.4 and 2.3, respectively. There were no surgical deaths or sternal infection. The left and right ITA were anastomosed to the LAD in 106 (73.6%) and 38 (26.4%) patients, respectively. There were no differences in preoperative conditions and postoperative complications between the left ITA and right ITA to LAD groups. The patencies of the left and right ITAs were 99.1 and 100%, respectively. In situ skeletonized bilateral ITA grafting for left-side revascularization using an off-pump technique was shown to be feasible, producing excellent early clinical and angiographic outcomes. Furthermore, arrangement of bilateral ITAs did not affect outcomes.
Key Words: Coronary artery bypass grafts; Coronary artery bypass grafting; Off-pump coronary artery bypass grafting
1. Introduction
Left internal thoracic artery (ITA) grafting has been shown to have better long-term patency rate and excellent clinical results compared to saphenous vein grafts [1]. Furthermore, better long-term outcomes have been demonstrated with bilateral ITA grafting compared to single ITA graft [2,3]. Especially, long-term benefits may be achieved when in situ bilateral ITAs are used for left-side myocardial revascularization [4]. Since the length and flexibility of ITAs are increased if they are harvested with a skeletonized technique, some reports have described the use of such grafts for multiple grafting [5]. However, there is still some reluctance to use bilateral ITAs because of technical difficulty, the prolonged operation time and increased chance of sternal infection.
Off-pump coronary artery bypass grafting (OPCAB) provides early and long-term benefits compared with conventional coronary artery bypass grafting (CABG) [6,7]. However, few studies have determined the optimum combination of OPCAB and in situ bilateral ITA grafting [7,8], and there remain concerns over the quality and patency of grafts when these techniques are combined.
This study aims to determine the early clinical and angiographic outcomes of using in situ bilateral skeletonized ITAs for multiple left coronary artery bypass grafting in patients undergoing OPCAB. We also assess the difference between left and right ITA grafting to the left anterior descending coronary artery (LAD).
2. Patients and methods
2.1. Patient population
Between April 2001 and July 2004, we performed isolated OPCAB in 602 patients at Shin-Tokyo Hospital. Of these, 336 patients (55.8%) received bilateral ITA grafts for myocardial revascularization, and of these, there were 144 (60.8%) whose bilateral ITAs were used as in situ grafts. In these patients, ITAs were not used as the inflow for the free grafts. Preoperative characteristics are summarized in Table 1. Diabetes, obesity, female gender and chronic obstructive pulmonary disease were not considered contra-indications of the need to harvest a bilateral ITA.
This study was approved by our institutional review committee, and informed consent was obtained from all patients with respect to the surgical method and postoperative angiography.
2.2. ITA harvesting
All ITAs were harvested in a skeletonized fashion using an ultrasonic scalpel. Radial arteries, gastroepiploic arteries and saphenous vein grafts were harvested in 55 patients (38.2%), 44 patients (30.6%) and 31 patients (21.5%), respectively (Table 2). Heparin was administered after all grafts were harvested.
2.3. Grafting of bilateral ITA
CABG strategy was to bypass all significant stenosis (a diameter reduction of at least 50%) in all coronary vessels larger than 1 mm in diameter. Since the long-term result of bilateral ITAs used for left coronary artery has been proved to be better than that used for right coronary artery (RCA) [4], we did not use the ITA for RCA. Arrangement of the ITAs, which ITA was used for the LAD and which ITA was used for the circumflex artery (Cx), was decided according to the coronary anatomy and quality of the graft, including its length. When the left/right ITA was used for the LAD, the right/left ITA was used for Cx revascularization. The choice and combination of other grafts were based on the coronary artery anatomy, severity of coronary stenosis, and size of the grafted vessel. Basically, the larger ITA was used for the LAD. When sequential grafting is necessary in the Cx, the longer ITA will be used for this region.
2.4. Surgical technique
Median sternotomy was performed in all patients. A deep pericardial stay suture was not used, and a commercially available heart positioner and stabilizer were applied to the heart (Starfish and Octopus, Medtronic Inc., Minneapolis, MN). A bloodless field was obtained using a proximal silastic snare suture and CO2 blower. All anastomoses were performed with an 8-0 polypropylene running suture.
When the right ITA was anastomosed to the Cx, it was routed through the transverse sinus. After the harvesting the right ITA, the distal end of the graft was clipped with silastic tape without twisting. A right-angled forceps was used to grasp the tape and pass the graft through the transverse sinus. When sequential grafting is constructed, diamond shaped side-to-side anastomosis and terminal T-shaped anastomosis are our preferred approaches [9]. When the right ITA was anastomosed to the LAD, it was directed anterior to the aorta. When possible, the right ITA was wrapped in thymic tissue and covered with mediastinal fat to prevent injury at reopening [10].
2.5. Angiographic study
Postoperative angiography was performed before discharge at 4 to 11 days (mean: 7.8±1.9 days) after surgery to assess graft patency in 110 patients (76.4%) who gave informed consent. Clinical and angiographic outcomes were then compared between those in whom the left ITA was grafted to the LAD and right ITA was grafted to the Cx (left ITA to LAD group) and vice versa (right ITA to LAD group).
2.6. Statistical analysis
Continuous variables are reported as the mean ± standard deviation. Continuous variables were compared using the Student's t-test and discrete variables were compared using the 2-test or Fisher's exact test. Differences were considered statistically significant at P<0.05. Statistical analyses were performed using the StatView 5.0 software package (SAS Institute Inc, Cary, NC).
3. Results
The average number of anastomoses per patient was 3.4±1.0 (range: 2–7) and the average number of bilateral ITA anastomoses was 2.3±0.5 (range: 2–4) (Table 2). The mean number of grafts per patient was 2.9±0.6. Bilateral ITA grafts only were used in 34 patients.
There were no surgical deaths (defined as death within 30 days after surgery); other morbidities are listed in Table 3. Re-exploration due to side-branch bleeding of the ITAs was not performed in any patients. Postoperative respiratory failure (defined as prolonged ventilator use for more than 48 h after surgery) was observed in three patients (2.1%). No sternal infection, superficial or deep, was observed.
3.1. Arrangement of ITAs
The left ITA was anastomosed to the LAD in 106 patients (73.6%) and the right ITA was anastomosed to the LAD in 38 patients (26.4%). Graft arrangement of the bilateral ITAs in these patients is listed in Table 4. The preoperative characteristics of the two groups did not differ (Table 1). The total number of anastomoses per patient in the left ITA to LAD group (3.5±1.0) was larger than that in the right ITA to LAD group (3.2±1.0); however, this difference did not reach statistical significance (Table 2). There were no differences in the number of bilateral ITA anastomoses per patient between the two groups (2.2±0.5 vs. 2.3±0.6). Although the number of grafts per patient was not different between groups, the radial artery was more frequently used in the left ITA to LAD group than the right ITA to LAD group (45.3% vs. 18.4%). There was no difference in postoperative complications and courses between the two groups (Table 3).
3.2. Angiographic results
The patency rate of the left ITA was 99.1% (109/110) and that of the right ITA was 100% (110/110). Only one ITA graft to the LAD was occluded. No stenosis of the right ITA due to compression by the aorta or kinking was observed in any patient. The patency rates of the radial arteries, the gastroepiploic arteries and saphenous vein grafts were 93.6% (44/47), 86.2% (25/29) and 100% (21/21), respectively.
4. Discussion
Bilateral ITA coronary artery bypass grafting has been shown to result in better survival than single ITA grafting [2,3]. Composite grafting using free ITA has been shown to result in a decreased midterm survival compared to in situ bilateral ITA grafting [10]. Especially, long-term benefits may be achieved when in situ bilateral ITAs are used for left-side myocardial revascularization [4]. It is possible to evaluate the outcomes of in situ ITA grafting from the angiographic results, because no ITA was used as an inflow graft in this study. The early clinical and angiographic results in our patients are excellent and comparable to those obtained in other studies using bilateral skeletonized ITAs [7,8]. These favorable results reveal the effectiveness and safety of the in situ bilateral ITA grafting for the left myocardial revascularization with off-pump technique.
There are two arrangements of the bilateral ITA grafting in left-side myocardial revascularization. One is anastomosis of the left ITA to the LAD and the right ITA to the Cx, and the other is anastomosis of the right ITA to the LAD and the left ITA to the Cx. The superiority of one of these two arrangements has never been determined. The first arrangement (left ITA to LAD) was employed in 73.6% of patients in the present study. Although it was easy to achieve these operative procedures, this arrangement has several limitations. The first is the length of the right ITA, which could sometimes not reach two or three lateral branches sequentially. The second is the course of the right ITA: a retroaortic course is disadvantageous because of the inability to control side-branch bleeding, compression by the aorta or undetected graft kinks. However, in our patients, no side-branch bleeding, stenosis or kinks were observed in postoperative angiography.
The second arrangement (right ITA to LAD) was used in 26.4% of patients under the assumption that the patency rates of both arrangements were identical [11]. Sequential grafting of the left ITA to the Cx was also easily performed. However, this arrangement also has a limitation. There is a compromise of surgical flexibility by anastomosing the right ITA in its distal and relative narrow part to the LAD. Since there were no differences in clinical and angiographic outcomes between these two arrangements in the present study, we suggest that arrangement should be decided upon according to the quality of the grafts and anatomy of the target vessels. We basically use the larger ITA for the LAD. When sequential grafting is necessary in the Cx region, the longer ITA will be used for this region.
The combination of OPCAB and arterial grafts is widespread [9,12]. Though sequential grafting using bilateral ITAs is somewhat technically demanding with a beating heart, the distance between the two anastomoses can be determined easily with the OPCAB technique [9]. In the present study, the average number of bilateral ITA anastomoses per patient was 2.3±0.5. As shown in the results, sequential grafting can be performed safely using either the left or right ITA with the off-pump technique. We believe that determining the correct direction and course of the conduit are important in preventing kinking, especially kinking of the right ITA through the transverse sinus.
A skeletonized ITA provides a longer length and better flexibility than a pedicled ITA [5]. Moreover, the blood flow of skeletonized ITA is reported to be greater than that of pedicled ITA [13]. As a result, grafting to a beating heart can be easily performed with skeletonized ITAs. Furthermore, with the skeletonization technique, the utilization of bilateral ITAs might no longer be a risk factor for mediastinitis, because the collateral blood supply to the sternum can be preserved [14,15]. In the present study, no sternal infection, superficial or deep, was observed using these techniques, although there was no selection bias for using bilateral ITAs.
The operation time in the present study may have been long with nearly 5 h. This may be because all grafts were harvested by residents in our institutes. Furthermore, the harvesting of the bilateral ITAs may take a longer time than harvesting a single ITA. However, we believe that in situ bilateral skeletonized with OPCAB is a safe method with least complication rate even though it relatively took a long time.
The present clinical study had the following limitations. The number of patients included was small and only early clinical and angiographic results were obtained. Furthermore, this was a retrospective observational study and not randomized. Lastly, because there was no control group, it is not possible to conclude that in situ bilateral skeletonized ITA grafting with OPCAB is superior to conventional CABG.
In conclusion, we demonstrated the feasibility of in situ bilateral skeletonized ITA grafts for left-side myocardial revascularization using the off-pump technique, revealing excellent early clinical and angiographic results. Moreover, arrangement of the bilateral ITA did not affect the results.
References
Cameron A, Davis KB, Green G, Schaff HV. Coronary bypass surgery with internal-thoracic-artery grafts – effects on survival over a 15-year period. N Engl J Med 1996; 334:216–219.
Rizzoli G, Schiavon L, Bellini P. Does the use of bilateral internal mammary artery (IMA) grafts provide incremental benefit relative to the use of a single IMA graft A meta-analysis approach. Eur J Cardiothorac Surg 2002; 22:781–786.
Calafiore AM, Di Giammarco G, Teodori G, Di Mauro M, Iaco AL, Bivona A, Contini M, Vitolla G. Late results of first myocardial revascularization in multiple vessel disease: single versus bilateral internal mammary artery with or without saphenous vein grafts. Eur J Cardiothorac Surg 2004; 26:542–548.
Schmidt SE, Jones JW, Thornby JI, Miller CC 3rd, Beall AC Jr. Improved survival with multiple left-sided bilateral internal thoracic artery grafts. Ann Thorac Surg 1997; 64:9–14.
Gurevitch J, Paz Y, Shapira I, Matsa M, Kramer A, Pevni D, Lev-Ran O, Moshkovitz Y, Mohr R. Routine use of bilateral skeletonized internal mammary arteries for myocardial revascularization. Ann Thorac Surg 1999; 68:406–411.
Sabik JF, Blackstone EH, Lytle BW, Houghtaling PL, Gillinov AM, Cosgrove DM. Equivalent midterm outcomes after off-pump and on-pump coronary surgery. J Thorac Cardiovasc Surg 2004; 127:142–148.
Calafiore AM, Di Giammarco G, Teodori G, Iaco AL, Pano M, Contini M, Vitolla G, Di Mauro M. Bilateral internal thoracic artery grafting with and without cardiopulmonary bypass: six-year clinical outcome. J Thorac Cardiovasc Surg 2005; 130:340–345.
Kim KB, Cho KR, Chang WI, Lim C, Ham BM, Kim YL. Bilateral skeletonized internal thoracic artery graftings in off-pump coronary artery bypass: early result of Y versus in situ grafts. Ann Thorac Surg 2002; 74:S1371–1376.
Fukui T, Takanashi S, Hosoda Y, Suehiro S. Total arterial myocardial revascularization using composite and sequential grafting with the off-pump technique. Ann Thorac Surg 2005; 80:579–585.
Lev-Ran O, Paz Y, Pevni D, Kramer A, Shapira I, Locker C, Mohr R. Bilateral internal thoracic artery grafting: midterm results of composite versus in situ crossover graft. Ann Thorac Surg 2002; 74:704–710.
Chow MS, Sim E, Orszulak TA, Schaff HV. Patency of internal thoracic artery grafts: comparison of right versus left and importance of vessel grafted. Circulation 1994; 90:Pt 2II129–132.
Quigley RL, Weiss SJ, Highbloom RY, Pym J. Creative arterial bypass grafting can be performed on the beating heart. Ann Thorac Surg 2001; 72:793–797.
Choi JB, Lee SY. Skeletonized and pedicled internal thoracic artery grafts: effect on free flow during bypass. Ann Thorac Surg 1996; 61:909–913.
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