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ORIGINAL CONTRIBUTIONS |
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Department of Cardiovascular Surgery Kobari General Hospital Noda City, Chiba, Japan 1 Department of Cardiovascular Surgery Shin-Tokyo Hospital Matsudo City, Chiba, Japan |
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| Hitoshi Hirose, MD Tel: 81 471 24 6666 Fax: 81 471 24 6764 email: genex{at}nifty.com Department of Cardiovascular Surgery, Kobari General Hospital, 29-1 Yokouchi, Noda City, Chiba 278-8501, Japan. |
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONPATIENTS AND METHODSRESULTSDISCUSSIONREFERENCES |
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONPATIENTS AND METHODSRESULTSDISCUSSIONREFERENCES |
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PATIENTS AND METHODS |
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TOPABSTRACTINTRODUCTIONPATIENTS AND METHODSRESULTSDISCUSSIONREFERENCES |
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). Since poorly controlled diabetic patients were not considered as candidates for quadruple arterial bypass, less than 10% of the study patients were insulin users.
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The left anterior descending artery was revascularized with one of the IMAs, preferably the LIMA. The RIMA was mostly used for revascularization of the diagonal artery. The GEA was primarily used for the distal right coronary artery system, while the RA was used for the circumflex artery including the posterolateral branches, the obtuse marginal branch, and the high lateral branch. Both the IMAs and the GEA were used as in situ grafts. The RA was used as a free graft; but if the proximal anastomoses posed a risk for stroke due to aortic calcifi-cation, it was used as a Y-graft in combination with the LIMA. The saphenous vein was used if additional anastomoses were required.
When quadruple arterial OPCAB was first performed in August 1999, its indication was limited to patients contraindicated for cardiopulmonary bypass (CPB), such as calcification of the aorta, recent stroke, renal failure, and other comorbidities. However, after March 2000, it was systematically performed if the patient had no contraindication for OPCAB, which was intramyocardial coronary arteries or severe calcification of the coronary arteries.
In all patients undergoing OPCAB, the heart was approached via a midline sternotomy. After harvest of the appropriate conduits, a local coronary stabilizer (Octopus; Medtronic, Minneapolis, MN, USA) was applied to the target coronary artery. Anastomosis was performed in the following sequence: posterior wall of the heart, lateral wall, anterior wall, and lastly the inferior wall. However, if the left anterior descending artery was the only collateral supply to the other coronary arteries, it was anastomosed first with one of the IMAs to avoid global ischemia. The posterior aspect of the heart was exposed with 4 retropericardial suspension sutures applied behind the heart,2 which was placed in the Trendelenburg position to provide further support. Blood pressure was maintained using appropriate inotropic agents and/or vasodilators administered by the anesthesiologist. Coronary pre-conditioning was not performed. Proximal and distal control of the target coronary artery was achieved using silicone occlusion tape. An intracoronary shunt tube was utilized during anastomosis of the culprit lesion. A carbon dioxide gas blower was used to obtain a bloodless operative field and to facilitate anastomosis. Coronary anastomosis was performed using 8/0 or 7/0 polypropylene sutures. In aortocoronary bypass, proximal anastomosis was performed last, with 6/0 polypropylene sutures under the side clamp applied to the ascending aorta.
Graft spasm was reversed by an intraluminal injection of diluted papaverine. The grafts were wrapped in warm papaverine-soaked sponges until use. To prevent peri-operative vasospasm, calcium channel blockers such as diltiazem and/or nicorandil were administered during the perioperative period, switching to oral administration on postoperative day 2.
Postoperatively, the patients were extubated when fully awake from general anesthesia. The patients were kept in the intensive care unit (ICU) until they were hemo-dynamically stable, and inotropic support was dis-continued. They were rehabilitated according to hospital protocol after transfer to the ward. The patients were discharged when they could tolerate work equivalent to a double-master exercise.
Pre-, intra-, and postoperative data were collected from medical records. The definitions of preoperative risk factors, postoperative complications, and late cardiac events were described elsewhere.4 Follow-up was completed by telephone by medical professionals. Post-operative angiographic control was performed within 1 year after surgery if the patient consented. If angina occurred after CABG, angiography was recommended.
Results were expressed as mean ± standard deviation. Statistical analysis was performed using Student's t test for continuous variables and the chi-squared test (Fisher's exact test if n < 5) for categorical variables. A p value < 0.05 was considered significant. All analyses were performed using StatView version 5.0 (SAS Institute, Cary, NC, USA).
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RESULTS |
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TOPABSTRACTINTRODUCTIONPATIENTS AND METHODSRESULTSDISCUSSIONREFERENCES |
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. No off-pump patients developed hypotension requiring emergent CPB support. The distribution of the distal anastomoses of each graft did not differ significantly between the 2 groups (Table 3). Because of diffuse coronary lesions, sequential bypass was performed in 8 off-pump patients and 32 on-pump patients.
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). The only major complication observed in the off-pump group was atrial fibrillation requiring electronic defibrillation. No postoperative stroke, renal failure, or pneumonia occurred in either group. There was 1 in-hospital death. The patient was a 74-year-old male who underwent on-pump redo quadruple arterial bypass, and he died of mediastinitis.
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). Because of the late introduction of OPCAB, the follow-up period in patients undergoing this procedure was only 6 months. No cardiac events or deaths occurred during this period. In the on-pump group, 4 cardiac events and 4 deaths occurred during the mean follow-up period of 2.2 ± 1.0 years.
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). No graft occlusion was observed in the OPCAB group, while there were 2 cases in the on-pump group. The stenosis-free patency rates of the grafts did not differ significantly between the 2 groups.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONPATIENTS AND METHODSRESULTSDISCUSSIONREFERENCES |
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The indications for quadruple bypass include relatively young age (usually below 65 years), revascularization of more than 4 vessels, a poor saphenous vein, and no contraindications for harvesting the 4 arterial grafts. The primary reason for quadruple bypass for elderly patients (over 75 years) is the lack of good venous grafts because of thrombosed or varicose veins. These indications apply regardless of whether anastomosis is performed on-pump with cardioplegic arrest or off-pump on a beating heart. Since uncontrolled diabetics were not considered for quadruple bypass, we have experienced only 1 case of postoperative sternal infection.
Exposure and local coronary stabilization play a key role in OPCAB, and the suction type of coronary stabilizer is an essential element of multivessel revascularization. In our hospital group, the compression type of coronary stabilizer was used until the suction device became available in mid-1999. The compression device allowed OPCAB to be performed only on the anterior surface of the heart since hemodynamics were difficult to maintain if it was applied to the posterior wall.12,13 Thus, when only the compression device was available, patients requiring quadruple bypass were referred for on-pump CABG. However, after the introduction of the suction device, together with retropericardial suspension, anastomosis on the posterior wall could be carried out without hemodynamic changes under beating heart conditions. Supported by our favorable early results with OPCAB,4 patients requiring isolated CABG are now referred for OPCAB instead of on-pump CABG.
The contraindications for OPCAB are now limited to intramyocardial coronary arteries and severely calcified coronary arteries. Denudation of the intramyocardial coronary artery under beating heart conditions is unsafe because of the high risk of ventricular perforation,14 and bypass to the intramyocardial coronary artery should be performed under cardiac arrest with CPB. Anastomosing to a calcified coronary artery under beating heart conditions is technically difficult. Local clamping of the calcified artery using silicone snare loops is not easy. Forceful application of the snare loops may result in coronary dissection, and an intracoronary shunt tube should be utilized in these cases.
Our results indicate that OPCAB allows earlier recovery than on-pump CABG even in quadruple arterial bypass. The operation time required for quadruple arterial bypass was longer than usual since graft harvesting is time-consuming. The LIMA and the RA can be harvested simultaneously, but not the other grafts. Bilateral IMA harvesting requires an additional 20 to 30 minutes, so does GEA harvesting. Although the operation time was relatively long, postoperative mortality and morbidity were minimal. No complications relating to the prolonged operation occurred in our study. OPCAB successfully reduced the intubation time by more than half, ICU stay by one-third, and postoperative hospital stay by about one-fourth, compared to on-pump CABG. Despite the shorter hospital stay of OPCAB patients, the length was almost 3 times that reported in the USA.15 This may be a reflection of the culture and health insurance program in Japan.
The early follow-up results of the patients undergoing quadruple arterial OPCAB were satisfactory. Long-term results remain to be determined. Graft occlusion occurred only rarely in our arterial conduits regardless of the surgical approach (off-pump or on-pump). However, graft stenosis should be carefully monitored. If initial angiographic control shows stenosis, angiography should be repeated within a year after the first one.
Our study was performed within a single hospital group with a single surgical team, which may bias the operative data. The majority of the patients were referred from outside the hospital. Only 10% of the patients were followed up at our outpatient clinics, while the rest were followed by local hospitals or private cardiologists, which may have affected the late results.
In conclusion, quadruple arterial bypass provides good clinical outcomes within a short follow-up period. OPCAB allows faster postoperative recovery. Follow-up results so far have been satisfactory.
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TOPABSTRACTINTRODUCTIONPATIENTS AND METHODSRESULTSDISCUSSIONREFERENCES |
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This article has been cited by other articles:
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  S. G Raja and G. D Dreyfus Current Status of Off-pump Coronary Artery Bypass Surgery Asian Cardiovasc Thorac Ann, April 1, 2008; 16(2): 164 - 178. [Abstract] [Full Text] [PDF]
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 R. Pandey, A. D. Grayson, D. M. Pullan, B. M. Fabri, and W. C. Dihmis Total arterial revascularisation: effect of avoiding cardiopulmonary bypass on in-hospital mortality and morbidity in a propensity-matched cohort Eur. J. Cardiothorac. Surg., January 1, 2005; 27(1): 94 - 98. [Abstract] [Full Text] [PDF]
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 P. A. Berdat, K. Muller, J. Schmidli, B. Kipfer, F. Eckstein, F. F. Immer, and T. Carrel Totally arterial off-pump vs. on-pump coronary revascularization: comparison of early outcome Interactive CardioVascular and Thoracic Surgery, March 1, 2004; 3(1): 176 - 181. [Abstract] [Full Text] [PDF]
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 J. T. Reston, S. J. Tregear, and C. M. Turkelson Meta-analysis of short-term and mid-term outcomes following off-pump coronary artery bypass grafting Ann. Thorac. Surg., November 1, 2003; 76(5): 1510 - 1515. [Abstract] [Full Text] [PDF]
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D. L. Ngaage Off-pump coronary artery bypass grafting: the myth, the logic and the science Eur. J. Cardiothorac. Surg., October 1, 2003; 24(4): 557 - 570. [Abstract] [Full Text] [PDF]
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