Myocardial revascularization without cardiopulmonary

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1 Multiple Arterial Conduits Without Cardiopulmonary Bypass: Early Angiographic Results Antonio M. Calafiore, MD, Giovanni Teodori, MD, Gabriele Di Giammarco, MD, Giuseppe Vitolla, MD, Nicola Maddestra, MD, Leonardo Paloscia, MD, Marco Zimarino, MD, and Valerio Mazzei, MD Division of Cardiac Surgery, University G. D Annunzio, Chieti and Division of Cardiology, Hospital of Pescara, Pescara, Italy Background. Lack of angiographic results and technical difficulty in grafting the vessels in the lateral and posterior walls have reduced interest in myocardial revascularization without cardiopulmonary bypass (CPB). We describe our experience to demonstrate the feasibility of coronary surgical intervention without CPB in multivessel disease. Methods. From May 21, 1997, through February 1998, 227 patients underwent revascularization with two or more arterial conduits as the first operation: 122 without CPB (group A) and 105 with CPB (group B). included a greater number of high-risk patients. Results. Mean SD anastomoses per patient were in group A and in group B (p NS). No patient died in group A, whereas 1 patient (0.9%) died in group B. The postoperative complication rate was low in both groups, but intensive care unit and in-hospital stays were shorter in group A than in group B ( versus hours, p < 0.001, and versus days, p < 0.001, respectively [group A versus group B]). Sixty-seven patients in (54.9%) underwent postoperative angiography days after operation. The patency rate was 98.9% (98.2% for the marginal branches). Conclusions. Arterial revascularization of the coronary arteries without CPB is feasible, with results similar to those obtained with CPB. The two techniques, in our opinion, are complementary, not antagonistic. (Ann Thorac Surg 1999;67:450 6) 1999 by The Society of Thoracic Surgeons Myocardial revascularization without cardiopulmonary bypass (CPB) is a surgical strategy that has been used since the beginning of coronary artery surgical intervention. Despite gratifying results in large series of patients [1, 2], coronary artery bypass grafting (CABG) without CPB has not been completely accepted because of lack of long-term and angiographic results and technical difficulties in grafting the marginal branches of the circumflex coronary artery. Recently, the possibility of grafting the left anterior descending coronary artery (LAD) with the left internal mammary artery (LIMA) through a left anterior small thoracotomy in a beating heart [3] stimulated a new interest in coronary surgical procedures without CPB. Technologic developments have allowed stabilization of the target coronary vessels independent of the surgical approach. We describe our initial experience with CABG without CPB using a median sternotomy with two or more arterial conduits in patients who underwent a first coronary revascularization and analyze the evolution of the surgical techniques and assess the early clinical and angiographic results. Accepted for publication July 8, Address reprint requests to Dr Calafiore, Department of Cardiac Surgery, G. D Annunzio University, San Camillo de Lellis Hospital, Via C Forlanini 50, Chieti, Italy ( calafiore@unich.it). Material and Methods Patients From January 1995 to February 1998, as the first operation, 181 patients underwent myocardial revascularization without CPB using two or more arterial conduits; they represent 20.5% of all 879 patients who underwent the same procedure in the same period. According to the technical evolution, this time frame can be divided in two periods. In the first period (from January 1995 to May 20, 1997) only patients with favorable anatomy were considered. However, only in patients with high risk factors for CPB were the marginal branches or the posterior descending artery grafted. The remaining patients had only grafts to the LAD, diagonal branches, or the right coronary artery proximal to the crux. During this period, 58 patients were operated on and represent 8.9% of the patients operated on during the same period with two or more arterial grafts. In the second period (from May 21, 1997, through February 1998), after a new, improved technique for exposure of the lateral, posterior, and inferior walls of the heart was developed, surgical indications were expanded to include every patient who showed the following characteristics: 1999 by The Society of Thoracic Surgeons /99/$20.00 Published by Elsevier Science Inc PII S (98)

2 Ann Thorac Surg CALAFIORE ET AL 1999;67:450 6 MYOCARDIAL REVASCULARIZATION WITHOUT CPB 451 Table 1. Preoperative Data a 1. The coronary vessels had to be epicardial, with an internal size greater than 1.2 mm, not calcified at the level of the anastomotic site. 2. The marginal branches had to be long, with a uniform internal size up to the midportion, which is often the anastomotic site, because the part of the marginal branch near the atrioventricular groove is generally accessible with difficulty. 3. Electric instability had to be not present because the risk of severe ventricular arrhythmias during manipulation is high. 4. Left ventricular ejection fraction itself was not a contraindication; however, an enlarged heart can make exposure of the lateral wall difficult. Need of multiple sequential grafts was considered a contraindication up to the end of December 1997 because we concentrated our attention in obtaining a good endto-side anastomosis. Since January 1998, sequential grafts were routinary performed without CPB if necessary. During the second period, 122 patients were operated on, 53.7% of those patients were operated on in the same period with two or more arterial grafts. The present report concerns this second group of patients because this group (group A) allowed a comparison with patients operated on with use of CPB during the same period (group B, n 105). Only 1 patient was not included in any group, because the anastomoses were performed both without and with CPB. Table 1 shows the preoperative data. Surgical Technique p Value Age (y) NS Female 30 (24.6%) 14 (13.3%) NS No. of diseased vessels NS LMCA 11 (9.0%) 15 (14.3%) NS LVEF NS 35% 13 (10.6%) 8 (7.6%) NS Diabetes 33 (27.1%) 29 (27.6%) NS Urgent operation 19 (15.6%) 13 (12.4%) NS High-risk factors 58 (47.5%) 30 (28.6%) 0.05 Age 75 y 15 5 NS Previous CVA 6 3 NS Malignancy 6 2 NS Diffuse vasculopathy 7 3 NS CRF 3 3 NS COPD NS Epathic cirrhosis 1... NS a Data presented are mean value SD, number (%) of patients, or number of patients. COPD chronic obstructive pulmonary disease; CRF chronic renal failure; CVA cerebrovascular accident; LMCA left main coronary artery; LVEF left ventricular ejection fraction; NS not significant. CORONARY ARTERY BYPASS GRAFTING WITHOUT CARDIOPULMO- NARY BYPASS. Anesthesia is induced with fentanyl and propofol and maintained with fentanyl and propofol and a mixture of nitrous oxide and oxygen. Muscular relaxation is obtained with pancuronium bromide. At the beginning of the procedure, a continuous infusion of nitroglycerin is administered; volume is added if necessary. Before any maneuver to expose the lateral or posterior walls, any infusion of vasodilating agent is stopped to let the systemic pressure rise. Small boluses of a vasopressor (metaraminole, 1 mg) are administered if necessary. In the final part of the operation, propofol delivery is decreased to allow rapid patient awakening. The mammary arteries are harvested skeletonized; the remaining conduits are harvested as previously described [4]. After partial heparinization (1 mg/kg body weight), all arterial grafts are prepared as previously reported [5]. The target coronary vessels are explored, and the surgical strategy is confirmed. Four slings (50 cm long, 3 cm wide) are enrolled and passed, two through the transverse sinus and two behind the inferior vena cava. The exposure of the lesions is obtained as follows. The LAD is exposed by placing a laparathomic sponge behind the heart; the artery is gently moved medially and is easily accessible. This maneuver is well tolerated and takes seconds. The diagonal branches are exposed in the same way. However, the two transverse sinus slings are moved so as to surround the lateral wall of the heart and are fixed to a towel in the right side of the sternotomy. This maneuver, well tolerated, moves the diagonal branches medially, making their position similar to the LAD (Fig 1A). To expose the marginal branches, the patient is placed in the Trendelenburg position and is rotated rightward. All vasodilators are stopped, and the systemic pressure is allowed to rise. The heart is then pulled upward, with the apex outside the sternotomy, and the target vessel is identified. Two slings (one from above and one from below) are crossed above the anastomotic site and fixed to a towel on the right side of the sternotomy. The other slings are positioned to improve the exposure. In the latter patients, exposure of the first portion of the intermediate branch and first marginal was improved using the strategy proposed by Lima (R. Lima, personal communication, January, 1998). Two stay sutures are positioned deep in the pericardium, just above the left superior pulmonary veins, and one more in the posterior pericardium, between the left inferior pulmonary vein and the inferior vena cava. The first two are pulled up to the left side of the patient, the latter to the right side. Because the pericardium is mobile at that level, this maneuver elevates and rotates rightward the base of the heart with the first two stay sutures, whereas the third stay suture maintains the apex outside the sternum. This position is well tolerated, and hemodynamic status remains unchanged. After hemodynamic stabilization, the anastomotic site is presented. If the slings have to be moved, this is done slowly, a few millimeters each time, waiting 20 to 30 seconds before moving them again (Fig 1B). Exposure of the inferior wall is obtained by pulling the heart upward in the vertical position, parallel to the diaphragm. Two slings (one from above and one from

3 452 CALAFIORE ET AL Ann Thorac Surg MYOCARDIAL REVASCULARIZATION WITHOUT CPB 1999;67:450 6 Fig 1. (A) The two slings passed through the transverse sinus (TS) are used to rotate the heart toward the median line, exposing the diagonal branch. (B) One sling from the transverse sinus (TS) and one from the inferior vena cava (IVC) are crossed just above the anastomotic site. The other sling from the inferior vena cava is used to increase the exposure of the lateral wall. (C) The slings from the transverse sinus (TS) cross the heart from left to right; the slings from the inferior vena cava (IVC) are directed upward to maintain the vertical position of the heart. below) are crossed above the target vessel but near the apex to maintain the heart in position. The remaining slings are positioned near the others to better maintain the heart in a vertical position and to improve exposure as necessary. This maneuver is well tolerated by the heart, and hemodynamic stabilization is obtained in a few seconds (Fig 1C). The right coronary artery proximal to the crux is exposed, pulling the acute margin up toward the aorta with 4-0 sutures. The two inferior vena cava slings are fixed to the left lateral portion of the sternotomy to improve exposure of the vessel. The coronary arteries are occluded before the anastomoses, as described previously for the left anterior small thoracotomy (LAST) operation [6]. The LAD and the main right coronary artery are occluded proximally and distally and the other branches only proximally. An oxygen blower makes the operative field dry at the moment of the anastomosis. Stabilization of the target vessel can be done pharmacologically or mechanically, or both. In the first part of our experience we used only diltiazem to reduce the movement of the heart; in September 1997 we began to use the MV stabilizer (CardioThoracic System, Cupertino, CA). Once exposure and stabilization are obtained, the artery is incised, and the anastomosis is performed with a single suture. For the LAD and the diagonal branches, a Prolene or Sharpoint 8-0 suture is used. If a right gastroepiploic artery is used, an 8-0 suture is also used because of the characteristics of the graft. When a marginal branch or the RCA is grafted, when the radial artery is used, or when the coronary wall is thick, a 7-0 needle is used. For the marginal branches it is mandatory to use the 7-0 needle because a needle longer and thicker than 8-0 is needed. At the end of every anastomosis the flow in the graft is measured using a flowmeter (Cardiomed, Medi- Stim Oslo, Norway; Transonic System, Ithaca, NY). Blood lost during the procedure is reinfused in the patient using a cell saver (Dideco, Mirandola, Modena, Italy). Protamine is reversed 1:1, and the wound is closed in the usual manner. CORONARY ARTERY BYPASS GRAFTING WITH CARDIOPULMONARY BYPASS. The technical aspects of the operation were as follows: Warm systemic perfusion was used together with intermittent antegrade warm blood cardioplegia [7]; all proximal anastomoses were performed during a single cross-clamping time.

4 Ann Thorac Surg CALAFIORE ET AL 1999;67:450 6 MYOCARDIAL REVASCULARIZATION WITHOUT CPB 453 Hemodynamic Data To evaluate the hemodynamic changes related to cardiac manipulation, mean systemic pressure and cardiac output (thermodilution method; Baxter Explorer, Irvine, CA) were recorded in 10 patients before any maneuver and during the anastomosis. Postoperative Course The patients were admitted to the intensive care unit, where they remained until extubation and clinical stabilization; intravenous diltiazem was given. Patients were transferred to the ward (generally on the same day as the operation or in the first postoperative day); diltiazem (60 mg, three times a day) was given orally and was continued for 4 weeks. On the morning of the first postoperative day, all infusion lines and drainage tubes were removed, and the patients were ambulatory. If the patient agreed, control angiography was performed before hospital discharge in group A; if, for practical reasons, this was not possible, angiography was performed a few days or weeks later. One, 3, and 6 months postoperatively, all the patients were seen in the outpatient clinic and were asked to perform a stress test. Statistical Analysis Results are expressed as mean value SD, unless otherwise indicated. Statistical analysis comparing two groups was performed with an unpaired two-tailed t test for mean values or a 2 test for categoric variables. Survival and event-free survival curves were obtained with the Kaplan-Meier method (BMDP 1L software). Statistical significance was calculated using the Mantel- Cox and z tests. A p value less than 0.05 was considered significant. Results All but 1 patient in whom operation was attempted underwent myocardial revascularization without CPB. In 1 patient, the second marginal branch could not be adequately visualized, and anastomosis was performed with CPB. This patient was not included in any group (his outcome was uneventful). Technical Details Most patients in both groups achieved total arterial myocardial revascularization (78.3% in group A, 69.4% in group B, p NS). Arterial conduits, distal anastomoses, and associated operations are shown in Table 2, whereas different conduit arrangements are shown in Table 3. Two arterial conduits were used in 95 patients in group A and 84 patients in group B, three in 26 patients in group A and 21 patients in group B, and four only in 1 patient in group A. The mean anastomoses per patient were 2.5 in group A but increased to 2.8 in the last 2 months. Hemodynamic Results Hemodynamic data are shown in Table 4. Table 2. Operative Data a Arterial conduit LIMA RIMA RGEA RA IEA 2 1 Saphenous vein graft Distal anastomosis LAD D OM RCA PDA Associated carotid operation 1 4 Anastomoses/patient Mean SD Range a Data presented are number of patients, unless otherwise indicated; p NS for all comparisons. D diagonal branch; IEA inferior epigastric artery; LAD left anterior descending coronary artery; LIMA left internal mammary artery; NS not significant; OM obtuse marginal branch; PDA posterior descending coronary artery; RA radial artery; RCA right coronary artery; RGEA gastroepiploic artery; RIMA right internal mammary artery. Early Deaths No patient died in group A, whereas 1 patient in group B died 6 days after operation because of acute myocardial infarction (mortality rate 0.9%). Postoperative Course Postoperative data are shown in Table 5. The intensive care unit stay was lower in group A than in group B, and Table 3. Conduit Arrangements a Arterial Conduit p Value LIMA RGEA 8 1 NS LIMA RA 4 2 NS LIMA IEA... 1 NS LIMA RGEA RA 1 1 NS LIMA RA SVG 2... NS BIMA NS BIMA RGEA NS BIMA RA 10 8 NS BIMA IEA 1 1 NS BIMA RGEA IEA 1... NS BIMA SVG NS Y grafts NS Sequential grafts a Data presented are number of patients. BIMA bilateral internal mammary artery; IEA inferior epigastric artery; LIMA left internal mammary artery; NS not significant; RA radial artery; RGEA gastroepiploic artery; SVG saphenous vein graft.

5 454 CALAFIORE ET AL Ann Thorac Surg MYOCARDIAL REVASCULARIZATION WITHOUT CPB 1999;67:450 6 Table 4. Hemodynamic Data for 10 Patients a Grafted Vessel CO (mean SD) MSP (mean SD) Baseline DA Baseline DA LAD OM PDA a p NS for all comparisons. CO cardiac output; DA during anastomosis; LAD left anterior descending coronary artery; MSP mean systemic pressure; NS not significant; OM obtuse marginal branch; PDA posterior descending coronary artery. 26.2% of patients were discharged by the first 6 hours. Postoperative complications were lower in both groups. Only 1 patient in group B (0.9%) had a cerebrovascular accident and died late of complications related to residual deficit. The postoperative in-hospital stay was significantly less in group A than in group B ( versus days, p 0.001; median, 4 and 5 days, respectively). Table 5. Postoperative Data a Variable p Value Time to awakening (h) Mechanical ventilation (h) NS Inotropes ( 12 h)... 5 (5.7%) NS AMI... 1 NS Bleeding (ml) NS Redo for bleeding 1 (0.8%)... NS Transfusion 18 (14.7%) 25 (23.8%) NS ARF... 2 (1.9%) NS CVA... 1 (0.9%) NS AF 12 (9.8%) 13 (12.3%) NS 30-day death... 1 (0.9%) NS ICU stay (h) (26.2%) 2 (1.9%) (21.3%) 3 (2.8%) NS (30.3%) 25 (23.8) NS (20.5%) 57 (54.3%) (1.6%) 18 (17.1%) Postop hospital stay (days) Discharge day NS NS NS a Data presented are mean value SD, number (%) of patients, or number of patients. AF atrial fibrillation; AMI acute myocardial infarction; ARF acute renal failure; CVA cerebrovascular accident; ICU intensive care unit; NS not significant. Fig 2. The left internal mammary artery (LIMA) is anastomosed to the left anterior descending coronary artery. The right internal mammary artery (RIMA), connected proximally to the left internal mammary artery, is anastomosed to the obtuse marginal branch. The inferior epigastric artery (IEA) goes from the right internal mammary artery to the first diagonal branch. Clinical Results The follow-up period ranged from 1 to 9 months. Two patients in group B died (1 in the second and the other in the third postoperative month) of complications related to an early cerebrovascular accident and intestinal infarction. One patient in group A had postoperative angina 3 months after operation because of occlusion of a saphenous vein graft on a second marginal branch. He underwent successful percutaneous transluminal coronary angioplasty 7 months after operation and is now asymptomatic. No patient in group B had recurrence of angina. We were able to collect data from 137 of 138 patients with negative stress test results among the survivors, the remaining being clinically well. Globally, after a mean follow-up period of months, 121 patients in group A (99.1%) and 102 in group B (97.1%) are alive ( p NS), and 120 in group A (98.3%) and 102 in group B (97.1%) are alive and asymptomatic without medical treatment ( p NS). After 9 months, the actuarial survival rate was 99.1% 0.8% in group A and 95.9% 1.6% in group ( p NS); the actuarial event-free survival rate was 96.0% 1.7% in group A and 95.9% 1.6% in group B ( p NS). Postoperative Angiography After a mean period of days after operation, 67 patients (54.9%) in group A underwent angiography (23 during the same hospital period) (Figs 2 4); the details are shown in Table 6. Three sequential grafts and 14 Y grafts were restudied; all anastomoses, including the intermediate one in the Y grafts, were perfectly patent (grade A). According to the classification of Fitzgibbon and colleagues [8], the patency rate (grade A plus B) was 98.9% (183 of 185); the perfect patency rate (grade A) was

6 Ann Thorac Surg CALAFIORE ET AL 1999;67:450 6 MYOCARDIAL REVASCULARIZATION WITHOUT CPB 455 Table 6. Postoperative Angiographic Findings in Grafted Vessel No. of Patients Grade (no. of patients) A B 0 LAD a... D OM RCA PDA Total (98.5%) 1 (0.5%) 2 (1%) a Reversed to grade A, 44 days after first angiography. LAD left anterior descending coronary artery; D diagonal branch; OM obtuse marginal branch; PDA posterior descending coronary artery; RCA right coronary artery. Fig 3. The left internal mammary artery is anastomosed to the left anterior descending coronary artery. The right internal mammary artery goes from the left internal mammary artery to the first and second obtuse marginal branches (OM1 and OM2, respectively). 98.4% (182 of 185). However, subsequent angiography, performed 44 days after the first angiography, showed a reversal to normal of the conduit shape (Fig 5) in only the grade B anastomosis, making the perfect patency rate equal to the patency rate (98.9%). Only 4 patients in group B underwent postoperative angiography, 12 anastomoses were checked (four on the LAD, one on the diagonal branch, four on the obtuse marginal branch, three on the posterior descending coronary artery), and all were grade A. Fig 4. The right gastroepiploic artery (RGEA) is grafted to the posterior descending artery. Comment Lack of angiographic studies in patients who underwent coronary surgical procedures with a beating heart has led surgeons to question the safety and efficacy of these operations, including patency rate. Most series reporting on coronary surgical intervention without CPB have used old technology and incomplete reporting of data, which may not truly reflect the current practice of coronary operations. Technologic advances have allowed construction of an anastomosis in a beating heart for arteries in the anterior surface of the heart. In the present study, the marginal branches of the circumflex coronary artery were bypassed in a beating heart through a median sternotomy, with angiographic studies that were performed early after operation to confirm patency of the anastomosis. We compared our early results with those obtained in patients who had two or more arterial conduits during CPB. The present study was not randomized because the two strategies are, in our opinion, complementary, not antagonist. Postoperative mortality and morbidity were absent or low in both groups. The major difference was intensive care unit stay, which was significantly lower in group A than in group B. In group A, 26.2% of patients were discharged in the first 6 hours, allowing the use of a single intensive care unit bed for 2 patients. Also, hospital stay was significantly lower in group A, especially when the 23 patients who underwent angiography during this period, prolonging hospital stay 1 or 2 days more, are considered. Angiographic studies in group A showed good results. There was a high incidence of grade A anastomoses (98.9%). In particular, LAD grafts were patent in 100% of patients; in a single patient in this group a grade B anastomosis was present but reversed to grade A 44 days after operation, confirming our observations after the left anterior small thoracotomy operation [6]. Marginal branch grafts had a high patency rate (98.2%). This is a very important finding because lateral wall grafting is a major problem in myocardial revascularization without CPB. In conclusion, we demonstrated by carefully carried out angiographic studies that arterial revascularization of

7 456 CALAFIORE ET AL Ann Thorac Surg MYOCARDIAL REVASCULARIZATION WITHOUT CPB 1999;67:450 6 Fig 5. The left internal mammary artery is anastomosed to the left anterior descending coronary artery (LAD). (A) Routine angiography 8 days after operation shows severe stenosis in the conduit (arrow). (B) Forty-four days after baseline angiography the stenosis reversed spontaneously to normal anatomy. all the arteries of the heart is possible without use of CPB in selected patients, with results similar to those obtained with CPB. Technologic advances facilitated the procedure and may simplify the technique in the future. Our early clinical results indicate that the procedure is safe. Our angiographic studies demonstrate a satisfactory patency rate. Even if some loss of patency, still related to perioperative technical inadequacies, occurs during the first year, this is true for every coronary anastomosis, independent of surgical technique. References 1. Buffolo E, Silva de Andrade JC, Rodrigues Branco JN, et al. Coronary artery bypass surgery without cardiopulmonary bypass. Ann Thorac Surg 1996;61: Benetti FJ, Naselli G, Wood M, Geffner L. Direct myocardial revascularization without extracorporeal circulation. Experience in 700 patients. Chest 1991;100: Calafiore AM, Di Giammarco G, Teodori G, et al. Left anterior descending coronary artery grafting via left anterior small thoracotomy without cardiopulmonary bypass. Ann Thorac Surg 1996;61: Calafiore AM, Di Giammarco G. Complete revascularization with three or more arterial conduits. Semin Thorac Cardiovasc Surg 1996;8: Calafiore AM, Di Giammarco G, Luciani N, et al. Composite arterial conduits for a wider arterial myocardial revascularization. Ann Thorac Surg 1994;58: Calafiore AM, Di Giammarco G, Teodori G, et al. Midterm results after minimally invasive coronary surgery (LAST operation). J Thorac Cardiovasc Surg 1998;115: Calafiore AM, Teodori G, Mezzetti A, et al. Intermittent antegrade warm blood cardioplegia. Ann Thorac Surg 1995; 59: Fitzgibbon GM, Kafka HP, Leach AJ. Coronary bypass graft fate and patient outcome: angiographic follow-up of 5,065 grafts related to survival and reoperation in 1,388 patients during 25 years. J Am Coll Cardiol 1996;28: