Asian Cardiovasc Thorac Ann 1999;7:177-181
© 1999 Asia Publishing EXchange Pte Ltd
Minimally Invasive Coronary Artery Bypass: Experience in 114 Patients
enol Yavuz, MD,
M Adnan Celkan, MD,
Cüneyt Eri
, MD,
Mustafa Mavi, MD,
Tamer Türk, MD,
Osman Tiryakio
lu, MD,
Yusuf Ata, MD,
Vedat Koca, MD,1,
Ayhan Özdemir, MD
Department of Cardiovascular Surgery
1 Department of Cardiology
Bursa Yüksek htisas Hospital
Bursa, Turkey
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For reprint information contact: enol Yavuz, MD Tel: 90 224 360 5055 Fax: 90 224 360 2928 Department of Cardiovascular Surgery, Bursa Yüksek htisas Hospital, Duaçinari 16330, Bursa, Turkey.
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Abstract
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From February 1996 to May 1998, 114 patients underwent a small (6 to 8 cm) left anterior thoracotomy for single-vessel coronary artery bypass grafting on a beating heart. There were 85 men and 29 women with a mean age of 63.1 ± 9.4 years, ranging from 36 to 84 years, and a mean preoperative ejection fraction of 53.2% ± 6.9%. The left internal mammary artery was anastomosed to the left anterior descending coronary artery under direct vision without cardiopulmonary bypass. There was no mortality. Postoperative morbidity included superficial wound infection in 3 patients. The length of the left internal thoracic artery was insufficient in two patients and the radial artery was used as an extension. Sixty-five (57%) patients underwent repeat coronary angiography (49 early, 16 late) and all grafts were patent. On intraoperative transesophageal echocardio-graphy, no segmental wall motion was seen during local coronary occlusion. Mean operative time was 1.7 ± 0.3 hours. One hundred and three patients (90%) were discharged 2 to 4 days postoperatively. The mean follow-up was 21.7 months. Minimally invasive surgery for left anterior descending coronary artery revascu-larization was considered to be a simple and effective alternative to the standard operation or angioplasty in selected patients.
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Introduction
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Coronary artery bypass grafting (CABG) on a beating heart without cardiopulmonary bypass (CPB) has a potential advantage because of its minimal effect on patient physiology.1–3 Recent efforts in myocardial revascu-larization have focused with increasing enthusiasm on a less invasive surgical approach.4–6 The potential for decreased patient morbidity, shorter hospital stay, an accelerated return to active life, and lower cost are the advantages of minimally invasive surgery. We report our clinical experience in 114 minimally invasive coronary bypass operations without CPB through a small left anterior thoracotomy with left internal thoracic artery (LITA) harvesting under direct vision to accomplish myocardial revascularization.
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Patients and Methods
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From February 1996 to May 1998, 114 patients underwent LITA-to-left anterior descending coronary artery (LAD) anastomosis at Bursa Yüksek htisas Hospital. All patients gave informed written consent. There were 85 men (74.6%) and 29 women (25.4%) with a mean age of 63.1 ± 9.4 years, ranging from 36 to 84 years. The patient characteristics are shown in Table 1
. Preoperative mean left ventricular ejection fraction was 53.2% ± 6.9%, ranging from 32% to 73%. The selection criteria included patients with severe LAD disease in whom percutaneous transluminal coronary angioplasty was not feasible and those with associated systemic diseases that carry a high risk for CPB (e.g. chronic renal failure, malignancy, or morbid obesity). Six patients had previous angioplasty or stent implantation. Only one patient underwent surgery on an emergency basis. Marked calcification in the ascending aorta was determined by preoperative chest radiography in 5 patients. There were no cases of comorbidity of other coronary arteries. Patients with left main disease and those with combined valvular and coronary diseases were excluded.
Anesthetic techniques included premedication with midazolam, induction with fentanyl and pancuronium bromide, and maintenance with isoflurane and fentanyl if needed. All patients were monitored with radial arterial, central venous, and pulmonary arterial catheters. External defibrillation pads were placed. A CPB pump was on standby in the operating room for the first 30 patients. The patients were placed in a 30-degree right lateral decubitus position and draped as for conventional CABG.
A small (6 to 8 cm) left anterior thoracotomy incision was made from near the nipple to the breast bone, over the anterior part of the fourth rib, with excision of the fourth costal cartilage. Exposure and dissection of the LITA was accomplished with single-lumen intubation. LITA harvesting up to the level of the first intercostal space was easily performed under direct vision through this incision, with sufficient proximal mobilization for anastomosis. It was harvested as a pedicle with control of the side branches by clips. The LITA was treated with topical papaverine to provide better initial flow and facilitate the anastomotic procedure. Mean arterial pressure was kept at 90 mm Hg and heart rate was reduced to 50 beats•min–1 by continuous intravenous diltiazem (10 mg•h–1); small boluses were injected when necessary. The patient was systemically heparinized with 10,000 units of sodium heparin. In addition, nitroglycerin was given to reduce myocardial ischemia. Intraoperative transesophageal echocardio-graphy was used to monitor ventricular wall motion during occlusion of the LAD for anastomosis.
The pericardium was opened anterior to the phrenic nerve by a vertical incision. Excellent exposure was obtained by elevating the heart with stay sutures placed on the pericardium. These stay sutures were important both for visualization of the LAD and for partial immobilization of the heart. The stay sutures also prevented the insufflated lung from obscuring the surgeon's view. Snare sutures of 4/0 polypropylene (Prolene; Ethicon Ltd., Edinburgh, Scotland, UK) were placed around the LAD, proximal and distal to the site selected for arteriotomy. The sutures were snared with thin silicone rubber, keeping the operative field dry. The vessel was occluded at the time of the anastomosis. No ischemic preconditioning was performed. The LITA-to-LAD anastomosis was made on a beating heart during immobilization of the LAD by the snare sutures. Anastomosis was performed with a running 7/0 Prolene suture, facilitated by irrigation or suction to clear the vessel, and completed in 8 to18 minutes (mean, 13.2 minutes). The graft was deaired and flow was re-established. After completion of the procedure, heparin was totally reserved with protamine. The pericardium was partially closed with care not to kink the LITA. Standard closure of the thoracotomy wound was employed, leaving a small thoracic catheter inside the pericardium.
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Results
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There were no incidents of injury to the LITA during mobilization under direct vision. The distal pedicle was exteriorized and demonstrated good flow in all patients. In 2 patients, the radial artery was used as an extension between the LITA and the LAD because of insufficient length of the LITA due to the lateral nature of the LAD. On intraoperative transesophageal echocardiography, no segmental wall motion was seen during local coronary occlusion. The procedure was tolerated well by all patients. Mean operative time was 1.7 ± 0.3 hours (Table 2). Mean postoperative mechanical ventilation time was 4.3 hours, ranging from 2 to 11 hours.
There was no inhospital mortality. Postoperative complications are listed in Table 3. Low cardiac output syndrome was noted in one patient who required intra-aortic balloon pumping after emergency surgery following a failed angioplasty due to acute anterior myocardial infarction and who was considered high risk for CBP. Abnormal ST-segment changes were observed in one patient. There was no neurological disorder in any of the patients and none needed reexploration for bleeding. Blood products (fresh frozen plasma) were used in 5 patients (4.4%). Mean blood drainage was 230 mL in the first 12 hours. Postoperative angiography was performed in 49 patients (43%) before discharge and all grafts were patent in the early postoperative period (Figure 1). We did not observe large side-branches of the LITA in any of the patients at angiography (Figure 2). No redo operation via conventional median sternotomy was necessary in any of the patients.
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Figure 1. Early postoperative angiogram demonstrating a patent left internal thoracic artery (arrow) anastomosis to the left anterior descending coronary artery (arrowhead) with proximal and distal run-off.
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Figure 2. On an early postoperative angiogram, large side branches of the left internal thoracic artery (arrow) are not observed.
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One hundred and three patients (90%) were discharged home 2 to 4 days postoperatively. In the late postoperative period, 16 patients (14%) underwent angiography that showed the grafts were patent (Figure 3). We confirmed the patency of the LITA by duplex scanning in the early and late postoperative periods in the last 57 patients. Pulsed Doppler spectrum analysis demonstrated a change from systolic to a predominantly diastolic flow pattern.
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Figure 3. Late postoperative (22 months) angiogram. Arrow = left internal thoracic artery, arrowhead = left anterior descending coronary artery.
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All patients were alive and clinically event-free (except in the 2 patients mentioned above) at a mean follow-up period of 21.7 months (range, 6 to 33 months). At follow-up, the functional status of the patients according to the classification of the New York Heart Association was class I in 112 patients (98.2%) and class II in 2 (1.8%).
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Discussion
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The gold standard for direct myocardial revascularization is still open-chest CABG with CPB and cardioplegic arrest. However, early follow-up after minimally invasive surgery indicates this approach maintains the effectiveness of the operation, reduces cost, accelerates patient recovery, and decreases hospital stay.1–3,7,8
The LITA can be taken down through a small left anterior thoracotomy and its dissection can be limited below the second rib because the LAD is closer to the LITA than in a conventional sternotomy. However, if postoperative coronary steal is of concern because of a large intercostal artery, further proximal dissection is mandatory. One or more costal cartilages may be resected to improve visualization and dissection of the LITA. We performed LITA harvesting up to the first intercostal space under direct vision but it may also be harvested by thoraco-scopy.4,6,9 A median sternotomy should be avoided in some redo CABG cases in which repeat sternotomy has been associated with increased mortality and morbidity. The left thoracotomy approach has been used to avoid injury of a patent old graft and the myocardium where severe mediastinal adhesion is suspected.10 A right thoracotomy has been used for redo right coronary bypass procedures.11
CABG without CPB is gaining popularity for myocardial revascularization in suitable cases.1–3,8 It is not only practical and economical but also very useful in situations where there are risks associated with cannulation, hypothermia, or CPB.2 CABG without CPB was first performed by Kolessov12 in 1967. In the early 1970s, Ankeney13 advocated bypass grafting to the right coronary artery and the LAD on a beating heart without CPB. Recently, a left minithoracotomy or left mediastinotomy has been used to perform LITA-LAD anastomosis on a beating heart with the aid of a thoracoscope or with the support of femorofemoral bypass.4,6,14–16 Calafiore and colleagues5 popularized minimally invasive CABG through a small left anterior thoracotomy and reported the largest series, extending the indication to patients with multivessel coronary disease. With this approach, the heart moves up and down while the pericardium and left lung remain in place. Go and colleagues17 developed a new technique that allows minimally invasive direct CABG in the setting of multivessel disease using small bilateral anterior thoracotomies.
The most attractive aspect of off-pump operations is a marked decrease in the need for postoperative trans-fusions.12 In our study, only 5 patients required blood products. The second major advantage of off-pump operation is a decrease in low cardiac output syndrome. In our experience, only one patient developed low cardiac output syndrome and occlusion of the distal LAD caused no hemodynamic change or rhythm disturbance in any of the patients.
The 12-year experience of Benetti and colleagues1 of CABG on a beating heart in 700 patients, showed 4% morbidity and 1% mortality, only 10% of patients required blood products, and 91% of patients were extubated immediately postoperatively. Pfister and colleagues2 compared the outcome of 220 off-pump operations with 220 conventional operations matched for number of grafts and left ventricular function; left ventricular function was better preserved in the off-pump procedures. Buffolo and colleagues3 reported 1274 consecutive carefully selected patients undergoing direct CABG without CPB with an acceptable mortality of 2.5% and a myocardial infarction rate of 4.8%. In our experience, there were no early or late (33 months) deaths or reoperations and the myocardial infarction rate was 0.9%. This technique is particularly useful in high-risk patients such as those with renal failure, respiratory problems, advanced age, cerebrovascular accidents, and other systemic diseases.3
Current techniques used to stabilize the coronary artery for anastomosis on a beating heart include epicardial sutures, finger stabilization, and pharmacologic slowing of the heart rate. For better stabilization of the artery, traction sutures to the pericardium lateral to the LAD, a suction device, or a stabilizer can be used. Traction sutures also aid visualization of the LAD. Alternatively, the vessel can be opened and an occluding device placed intra-luminally. Snares surrounding the coronary vessel achieve good exposure as well as fixing the heart. Any intimal or transmural damage to the native coronary vessel, which may result in either acute occlusion by spasm or thrombosis, or provocation of intimal hyperplasia, is of concern. Perrault and colleagues18 reported that experimental snaring of the coronary artery for hemostasis at the anastomotic site did not cause endothelial dysfunction.
The advantages of minimally invasive CABG derive primarily from avoidance of the adverse effects of CPB and secondarily from limited incisions. In our study, there was a cost saving due to decreased use of operating room equipment such as oxygenators, cardioplegic sets, and cannulas, as well as shorter intensive care unit and hospital stay. With no mortality, acceptably low morbidity, and satisfactory graft patency, we concluded that minimally invasive coronary bypass surgery was a safe and efficacious technique. We recommend it for selected patients as an alternative to interventional procedures (angioplasty and stent implantation) and standard CABG.
Presented in part at Current Trends in Thoracic Surgery IV, New Orleans, LA, USA, January 24, 1998.
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References
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Abstract
Introduction
