Asian Cardiovasc Thorac Ann 2001;9:7-9
© 2001 Asia Publishing EXchange Pte Ltd
Thoracoscopic Internal Thoracic Artery Harvest: Angiographic Assessment
Nobuaki Hirata, MD,
Shigeaki Ohtake, MD,
Yoshiki Sawa, MD,
Masao Yoshitatsu, MD,
Hiroshi Kato, MD1,,
Nobukazu Ohkubo, MD1,,
Hikaru Matsuda, MD
First Department of Surgery Osaka University Medical School Osaka, Japan
1 Division of Cardiovascular Surgery Toyonaka Municipal Hospital Osaka, Japan
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For reprint information contact: Nobuaki Hirata, MD Tel: 81 797 87 1161 Fax: 81 797 87 5624 Division of Cardiovascular Surgery, Takarazuka Municipal Hospital, 4-5-1 Kohama, Takarazuka, Hyogo 665-0827, Japan.
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Abstract
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Minimally invasive direct coronary artery bypass grafting was carried out in 10 patients. The left internal thoracic artery was mobilized under direct vision in the first 5 and by thoracoscopy in the next 5. Postoperative arteriography confirmed the advantage of thoracoscopic arterial harvest. The length of the thoracoscopically harvested artery was 10 ± 2 cm compared to 6 ± 1 cm for grafts harvested under direct vision (p < 0.05). The anastomotic angle between the internal thoracic artery and the left anterior descending coronary artery was 43° ± 4° for thoracoscopically harvested grafts versus 62° ± 5° for the direct vision method (p < 0.05). One anastomotic complication (occlusion) was found in a patient who had arterial harvest under direct vision. Internal thoracic artery harvested by thoracoscopy diverges from the chest wall and runs directly to the anastomotic site. Such a conduit harvested by direct vision runs along the chest wall until near the anastomotic site, which might increase the risk of anastomotic complications.
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Introduction
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Minimally invasive direct coronary artery bypass (MIDCAB) is still in the evolutionary phase. Internal thoracic artery (ITA) harvest presents one of its challenges. Although the ITA is usually mobilized through an incision under direct vision, ITA takedown can be difficult because of complications such as insufficient length for coronary anastomosis at the selected site, the risk of kinking, and coronary steal syndrome.1 Some studies have demon-strated the usefulness of a thoracoscopic technique that overcomes the drawbacks of the direct vision method, in spite of being technically more demanding and time- consuming.2–5 This study assessed both techniques by angiography.
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Patients and Methods
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From May 1997 to March 1998, 10 patients underwent MIDCAB by the same surgeon at our institute. All patients were men with a mean age of 57 ± 8 years (range, 48 to 69 years). There was isolated left anterior descending (LAD) coronary artery disease in 4 cases, 6 patients had double-vessel disease that included a LAD lesion. In the first 5 patients, the left ITA was mobilized through an incision under direct vision. In the next 5 patients, the left ITA was mobilized using a thoracoscope.
After standard anesthesia and endotracheal intubation with a double-lumen tube, the patient was placed in a 30-degree right lateral decubitus position and the left arm was flexed and suspended above the patient's head. A 6- to 8-cm left anterior thoracotomy was performed in the fourth intercostal space in 9 patients and in the fifth intercostal space in 1. The fourth or fifth costal cartilage was removed. In the first 5 patients, the ITA was harvested up to the second intercostal space from the medial part of the incision, under direct vision, and after collapsing the left lung. The length of the harvested ITA was 6 cm. In the next 5 patients, dissection of the ITA pedicle was started in the medial part of the incision and continued proximally with an ultrasonic scalpel using a thoracoscope (Olympus, Tokyo, Japan) after the left lung was collapsed.4 Trocars were introduced through 3 thoracic incisions of less than 15 mm at the level of the fourth and sixth intercostal spaces along the midaxillary line and at the level of the fifth intercostal space on the anterior axillary line. Ten-millimeter rigid thoracoscopes of 0° or 30° were used for visualization of the thoracic cavity and identifi-cation and exposure of the ITA. The ITA pedicle could be dissected further proximally above the first rib and distally underneath the fifth costal cartilage. The harvesting time using a thoracoscope was 35 ± 5 minutes.
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Results
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The harvested ITA grafts were used for LAD anastomoses. All patients underwent postoperative left ITA angiography on the third postoperative day. The ITA grafts harvested by thoracoscopy diverged from the chest wall and ran directly to the anastomotic sites. On the other hand, ITA harvested by the direct vision method ran along the chest wall until near the anastomotic site (Figure 1
). The length of the thoracoscopically harvested ITA was 10 ± 2 cm compared to 6 ± 1 cm for grafts harvested under direct vision (p < 0.05). The anastomotic angle between the ITA and LAD was 43° ± 4° for thoracoscopically harvested grafts compared to 62° ± 5° for the direct vision technique, p < 0.05 (Figure 2). Operative time was longer in patients who had thoracoscopic arterial harvest (253 ± 95 min versus 218 ± 25 min, p < 0.05). There was no operative mortality. One anastomotic complication (occlusion) was found in a patient who had arterial harvest under direct vision. The size of the left anterior thoracotomy incision was less in the thoracoscopic arterial harvest group (66 ± 1 cm) than in the direct vision arterial harvest group (8 ± 2 cm), p < 0.05.
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Figure 1a. Postoperative internal thoracic arteriograms in frontal and lateral views. (A) Internal thoracic artery harvested by thoracoscopy diverges from the chest wall and runs directly to the anastomotic site. (B) Internal thoracic artery harvested under direct vision runs along the chest wall until near the anastomotic site. Lateral views give the clearest comparison.
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Figure 1b. Postoperative internal thoracic arteriograms in frontal and lateral views. (A) Internal thoracic artery harvested by thoracoscopy diverges from the chest wall and runs directly to the anastomotic site. (B) Internal thoracic artery harvested under direct vision runs along the chest wall until near the anastomotic site. Lateral views give the clearest comparison.
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Figure 2a. (A & B). Measurement of the anastomotic angle between the internal thoracic artery and left anterior descending coronary artery. A tangent (t) of the left anterior descending coronary artery is drawn at the anastomotic site and the anastomotic angle is measured from the lateral view.
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Figure 2b. (A & B). Measurement of the anastomotic angle between the internal thoracic artery and left anterior descending coronary artery. A tangent (t) of the left anterior descending coronary artery is drawn at the anastomotic site and the anastomotic angle is measured from the lateral view.
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Discussion
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These angiographic results reconfirm the advantages of thoracoscopic ITA harvesting. This technique allowed ample dissection (longer ITA grafts were harvested) and provided better positioning with no tension or kinking of the anastomosis (the anastomotic angle was not acute), thus providing better results. Furthermore, thoracoscopic ITA harvest facilitated the use of a more proximal ITA portion for anastomosis, which may help to avoid the anastomotic complications of MIDCAB. However, the importance of adequate mobilization of the ITA cannot be over-emphasized.
Thoracoscopic techniques typify the disadvantages of MIDCAB. For example, more operative time is needed along with more instruments in the operating room. Nevertheless, we believe that the advantages of thoraco-scopic ITA harvest outweigh these disadvantages.
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References
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Abstract
Introduction
