Asian Cardiovasc Thorac Ann 2000;8:114-117
© 2000 Asia Publishing EXchange Pte Ltd
Grafts for Left Main Trunk Lesion Using "MIDCAB Doughnut" on Beating Heart
Masao Takahashi, MD,
Go Watanabe, MD,1,
Hidetoshi Furuta, MD,
Toshio Doi, MD,
Nobuyuki Tanaka, MD,
Takuro Misaki, MD,1
Department of Cardiovascular Surgery
Chigasaki Tokushukai Hospital
Kanagawa, Japan
1 Department of Surgery I
Toyama Medical and Pharmaceutical University
Toyama, Japan
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For reprint information contact: Masao Takahashi, MD Tel: 81 467 85 1122 Ext. 349 Fax: 81 467 83 9798 email: airdonut{at}nifty.com Department of Cardiovascular Surgery, Chigasaki Tokushukai Hospital, 14-1 Saiwai-cho, Chigasaki, Kanagawa 253-0052, Japan.
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Abstract
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Successful beating heart multiple bypass grafting to the left anterior descending and circumflex artery for a left main trunk lesion was performed in 5 patients through a left thoracotomy using the "MIDCAB doughnut" for immobilization and hemostasis. After completion of left internal thoracic artery-to-left anterior descending artery grafting, a radial artery or saphenous vein graft was anastomosed safely to the obtuse marginal branch, without hemodynamic deterioration. Extending the left anterior small thoracotomy 3 or 4 cm laterally, the obtuse marginal branch could be approached easily without rotating the beating heart. The device achieved a still and stable operative field even for circumflex grafting. An inflow of the graft to the circumflex was placed at the left axillary artery to prevent blood flow shortage to the left coronary system. Mean perioperative blood flow was 29.5 ± 7.1 mL•min–1 in the internal thoracic artery grafts and 43 ± 8 mL•min–1 in the circumflex grafts. Postoperative angiography revealed patency of all grafts. The technique may extend the surgical indications for beating heart bypass surgery without cardiopulmonary bypass.
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Introduction
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Minimally invasive coronary artery bypass grafting (CABG) without cardiopulmonary bypass has gained gradual widespread acceptance because of excellent clinical results and cost-effectiveness.1–4 However, technical difficulties may restrict the surgical indications in spite of these advantages. We developed the "MIDCAB doughnut" for immobilization and hemostasis of the anastomotic site on the beating heart.5,6 Safe and secure anastomoses can be achieved under a still and stable operative field using this device. The early graft patency rate was 100%.7 Minimally invasive CABG for multivessel disease has been performed using the MIDCAB doughnut.8,9 This report describes an alternative minimally invasive approach for patients with a left main trunk (LMT) lesion.
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Patients and Methods
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Five patients underwent double or triple minimally invasive CABG without cardiopulmonary bypass. All were male and the mean age was 68.2 ± 4.7 years (range, 62 to 87 years). All had LMT lesions without previous myocardial infarction, including a patient who required intraaortic balloon pumping due to unstable angina. Three patients had old brain infarctions and one had renal insufficiency. A 64-year-old patient had advanced rectal cancer. Another 64-year-old patient had received long-term bone marrow suppressive therapy for polycythemia vera.
The first 2 patients were intubated with a double-lumen endotracheal tube to permit selective ventilation. In the last 3 cases, a single-lumen endotracheal tube was used. The patient was placed in a slightly right lateral position with pillows under the left thorax. The left internal thoracic artery (LITA) was harvested by a thoracoscopic technique or under direct vision. At the same time, the right radial artery (RA) was dissected. In 2 patients, saphenous vein grafts (SVG) were used instead of RA because of a positive Allen's test. A left anterior small thoracotomy was performed in the fourth intercostal space and the pericardium was incised longitudinally to expose the left anterior descending artery (LAD). Extending the thoracotomy 3 or 4 cm laterally (Figure 1
), the obtuse marginal (OM) branch of the circumflex artery (CX) could be found easily through another pericardiotomy lateral to the left phrenic nerve. The left axillary artery was exposed and taped via a small left subclavian approach. After systemic heparinization (1 mg•kg–1), the LITA was divided distally and injected with 3 mL of saline solution containing papaverine.
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Figure 1. Photograph showing the skin incision of the second patient. Extending the left anterior thoracotomy 3 or 4 cm laterally, the obtuse marginal branch of the circumflex artery could be found easily.
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The LAD was surrounded with a proximal snare (5/0 polypropylene suture) and ischemic preconditioning was carried out twice to obtain hemodynamic stability. The LITA-to-LAD anastomosis was performed with a single 8/0 polypropylene continuous suture. The MIDCAB doughnut was used for immobilization and hemostasis without distal snaring. Blood flow in the graft was measured with a transit-time flowmeter (Cardiomed CM 2000; Medi-Stim A/S, Oslo, Norway). The pedicle was fixed next to the anastomotic site. One patient underwent additional bypass grafting to a large first diagonal branch using a composite graft of inferior epigastric artery from the LITA. After completion of the LITA-to-LAD anastomosis, RA or SVG was anastomosed to the left axillary artery. The posterior wall of the axillary artery was punched out using a 4-mm arterial puncher and the RA or SVG was anastomosed with 7/0 or 6/0 polypropylene continuous suture. The graft was carefully passed through a fingerbored hole in the first intercostal space. None of the costa were removed. The graft was located medial to the lung and next to the LITA-to-LAD graft.
An oblique-formed MIDCAB doughnut was specially developed for immobilization of the OM branch (Figure 2). After ischemic preconditioning, the distal anastomosis was safely accomplished on a beating heart. Using the instrument, immobilization as stable as that with cardioplegic arrest was achieved under routine intravenous infusion of low-dose diltiazem. A single 8/0 or 7/0 polypropylene suture was used for RA or SVG-to-OM grafting. The MIDCAB doughnut was removed and the graft flow was measured. The effects of heparin were reversed with protamine and the thoracotomy was closed. A single chest drainage tube was placed. One patient underwent triple grafting that comprised LITA to LAD, inferior epigastric artery to first diagonal, and RA to OM. The other 4 patients underwent double bypass grafting of LITA to LAD and RA, or SVG to OM.
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Figure 2. The oblique-formed MIDCAB doughnut. The MIDCAB doughnut is fixed around the entire anastomotic site by negative pressure.
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Results
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Double or triple minimally invasive CABG was performed safely without cardiopulmonary bypass in all cases. Perioperative graft flow measurements were very useful in ascertaining the accuracy of anastomoses of the grafts. Mean blood flow in the LITA-to-LAD grafts was 29.5 ± 7.1 mL•min–1 and in the CX grafts, it was 43 ± 8 mL•min–1. Flow patterns were found to be dominant in the diastolic segment.
There were no operative or hospital deaths. Postoperative angiography showed patent LITA-to-LAD grafts and RA or SVG to the OM branch (Figures 3A and 3B). Miles' operation was performed 3 weeks later in the patient who had rectal cancer. At the one-year follow-up examinations, all patients were free of angina and none had suffered a cardiac event.
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Figure 3A. Postoperative intra-arterial digital subtraction angiography in the first patient. Both the left internal thoracic artery-to-left anterior descending artery graft and the radial artery-to-obtuse marginal graft were patent.
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Discussion
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This study demonstrates that double or triple minimally invasive CABG can be performed successfully for LMT lesions. After accurate LITA-to-LAD grafting, bypass grafting to the CX could be carried out safely on a beating heart. An inflow to the CX graft was placed in the left axillary artery to prevent shortage of blood flow in the left coronary system due to the LMT lesion. This new operative technique may extend the surgical indications for bypass graft surgery on a beating heart without cardiopulmonary bypass.
The MIDCAB doughnut was invented by the first author.5–7 This instrument can create a motionless and bloodless operative field on the beating heart and it is not necessary to produce bradycardia with a beta-blocker or to induce transient ventricular asystole with adenosine. Even with heart rates over 80 beats per minute, safe and secure anastomoses could be completed in a still and stable operative field using this device. We would like to term the MIDCAB doughnut technique "mechanical cardioplegia." For grafting to the CX, a new type of MIDCAB doughnut was developed with a slightly oblique round base to fit over the lateral cardiac wall. The coronary artery can be easily dislocated after fastening the MIDCAB doughnut to the anastomotic site by negative pressure.
Minimally invasive axillary-coronary artery bypass has been reported previously in LAD grafting.10–12 Knight and colleagues10 described routing the SVG through a tunnel created at the site of resection of the fourth costal cartilage, behind the pectoralis major muscle, medial to the pectoralis minor muscle. Coulson and Bakhshay11 provided a window into the thorax for the SVG, created in the second rib by excising a one-inch section of the bone. Tovar and colleagues12 chose to resect the anterior portion of the first rib. In this series, an inflow to the CX graft was placed in the left axillary artery and rib resection was unnecessary; a hole bored in the first intercostal space by a finger maneuver was sufficient for passing the graft through (Figure 4).
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Figure 4. Axillary arterial inflow to the radial artery-to-obtuse marginal graft. The graft was passed through the first intercostal space without resection of the costa.
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For such high-risk patients as those with LMT lesions, the lateral thoracotomy approach is safer for CX grafting than a median sternotomy with rotation of the beating heart. The MIDCAB doughnut had no detrimental hemodynamic effects even in these high-risk patients because it fits over the epicardial surface by negative pressure; this technique of immobilization does not compress the myocardium.5–7 To prevent shortage of blood flow to the left coronary system, it is necessary in patients with LMT lesions that the inflow to the CX graft should be placed not in LITA as a composite graft, but in the axillary artery. Moreover, this technique using an axillary arterial inflow avoids touching the aorta and might reduce postoperative brain complications. The limitation of this technique is that the graft to the CX should be longer than the ascending aortic inflow. Long-term patency must be carefully examined.
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References
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Watanabe G, Misaki T, Kotoh K, Ueyama K. Left thoracodorsal artery as an inflow graft for minimally invasive direct coronary artery bypass grafting. J Thorac Cardiovasc Surg 1998;116:524–5.[Free Full Text]
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Abstract
Introduction
