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Ann Thorac Surg 1998;66:1012-1017
© 1998 The Society of Thoracic Surgeons
a Division of Cardiothoracic Surgery, Durham Veterans Administration Medical Center and Duke University Medical Center, Durham, North Carolina, USA
b Fuqua Heart Center, Piedmont Hospital, Atlanta, Georgia, USA
c The Christ and Jewish Hospitals and Department of Surgery, University of Cincinnati, Cincinnati, Ohio, USA
Address reprint requests to Dr Duhaylongsod, Duke University Medical Center, Box 3457 Med Ctr, Durham, NC 27710
e-mail: (duhay001{at}mc.duke.edu)
Presented at "Facts and Myths of Minimally Invasive Cardiac Surgery: Current Trends in Thoracic Surgery IV," New Orleans, LA, Jan 24, 1998.
Abstract
Background. Off-pump bypass grafting most commonly involves harvest of the left internal thoracic artery (ITA) through a minithoracotomy under direct vision. Disadvantages to this approach, however, include poor exposure, incomplete dissection resulting in inadequate ITA length, and significant postoperative pain because of rigorous chest retraction. This study determined the safety and efficacy of an alternative to direct ITA harvest using a thoracoscopic approach.
Methods. Two hundred eighteen patients at three institutions underwent thoracoscopic ITA harvest; 118 (54%) for off-pump coronary bypass grafting.
Results. The left ITA was harvested in 211 patients (96%); the mean harvest time ranged from 42 to 55 minutes. The ITA was injured in 4 patients (1.8%), and conversion to open ITA harvest occurred in 18 (8%). Complications included intercostal neuropathy (4), reoperation for ITA bleeding (2), phrenic nerve injury (1), and wound infection (1).
Conclusions. This large, multicenter experience demonstrates that thoracoscopic harvest of the ITA can be accomplished safely and within a reasonable time frame in most patients undergoing coronary bypass grafting.
Off-pump bypass grafting of the anterior descending coronary artery using an in situ left internal thoracic artery (ITA) is an operation that is gaining acceptance. The most common technique employs a 6- to 10-cm left anterior thoracotomy incision in the fourth intercostal space, with or without removal or dislocation of the third and fourth costal cartilages, and harvest of the left ITA under direct vision [1]. The anastomosis of the ITA to the coronary artery is then performed directly through the thoracotomy incision. Disadvantages to this approach, however, include (1) poor exposure of the ITA, making dissection difficult and potentially hazardous; (2) incomplete dissection of the ITA leading to inadequate length to permit a tension-free anastomosis; and (3) significant postoperative incisional pain because of costochondral dislocation or inflammation, rib fracture, intercostal myalgia, or neuralgia from mechanical trauma [2]. Insofar as the incisional pain restricts chest wall motion, pulmonary function is impaired [3] and physical activity is encumbered.
A potential solution is to perform the ITA harvest thoracoscopically [4]. This approach provides superior exposure and allows a meticulous and complete harvest of the ITA. Moreover, by avoiding costochondral resection or dislocation, and mechanical trauma to the intercostal muscles and nerves, this approach may alleviate postoperative incisional pain.
The objective of this study was to determine the safety and efficacy of thoracoscopic ITA harvest in a large, multicenter series of patients, to describe the fundamental technique on the basis of this experience, and to discuss the potential benefits and limitations.
Material and methods
All patients undergoing thoracoscopic harvest of the left ITA (LITA) or right ITA at Duke University Medical Center and the Durham Veterans Administration Medical Center (Duke), the Fuqua Heart Center at Piedmont Hospital (Atlanta), and The Christ and Jewish Hospitals (Cincinnati) provided the subject material for this report. At Duke subjects were prospectively enrolled in a research protocol approved by the institutional review board (June 7, 1996). Institutional review board approval was obtained to specifically examine the effects of thoracoscopic harvest on postoperative pulmonary function, pain, and quality of life. Because no such study was undertaken in Atlanta or Cincinnati, institutional review board approval was not obtained. Written, informed consent was obtained in all patients.
Anesthetic considerations
After standard intravenous induction, single-lung ventilation is achieved with a single-lumen tube combined with a bronchial blocker (Uni-vent; Fuji Systems, Tokyo, Japan) or a double-lumen endotracheal tube. The proper anesthetic plane is maintained with forane and oxygen without nitrous oxide. After complete collapse of the left or right lung, the thoracoscope (5- or 10-mm diameter) is inserted into the pleural cavity. During the procedure, the opposite lung is ventilated with a tidal volume of 6 to 8 mL · kg-1. Warm carbon dioxide gas is insufflated into the pleural cavity to a pressure of 8 to 10 mm Hg [5]. This significantly improves exposure by shifting the heart and the mediastinal and pericardial fat away from the anterior chest wall. Although the resultant pneumothorax may occasionally induce mild to moderate embarrassment of cardiac venous return with hypotension, this is readily corrected by decreasing gas flow, withdrawing the scope to vent the pleural space, or administering intravenous fluid. A diltiazem or nitroglycerin infusion is routinely started before harvest of the ITA to lessen arterial spasm. The infusion rate is titrated to maintain the systolic blood pressure at greater than 100 mm Hg. After operation, diltiazem or nitroglycerin administration is continued until oral intake is resumed, whereupon treatment with aspirin and either nifedipine or a nitroglycerin patch is begun.
Patient positioning for left internal thoracic artery harvest
The patient is positioned near the left edge of the table with a rolled towel placed beneath the left scapula or on a bean bag to slightly elevate the left chest 20 to 30 degrees. The left upper extremity is abducted 90 degrees and the forearm is flexed at the elbow and suspended above the shoulder with an orthopedic finger trap (S. Ronci Co, Inc, Franconia, NH). This relieves tension on the brachial plexus and permits unobstructed access to the left lateral chest wall. Alternatively, the left and right arm are extended and elevated toward the head by an orthopedic support or cushioned wedges (Alimed, Inc, Dedham, ME). In patients undergoing a limited left anterior thoracotomy, emergency external defibrillation pads were placed. The patient is prepared from neck to toe, and from bedline to bedline. The video monitor is placed directly across the operating table from the surgeon.
Technique of thoracoscopic harvest of the left internal thoracic artery
Thoracoscopic harvest of the LITA is performed through three skin incisions (Fig 1). First, a 5- to 10-mm incision is made in the fifth or sixth intercostal space in the anterior axillary line, for inserting a rigid 0-degree or 30-degree video thoracoscope (10-mm diameter, Stryker Endoscopy, Santa Clara, CA; 5-mm diameter, Genzyme Surgical Products, Cambridge, MA) or a flexible 0-degree video thoracoscope (10-mm diameter, Welch-Allyn, Skaneateles Falls, NY). Second, a 3- to 5-mm incision is made in the third or fourth intercostal space in the midaxillary line, for insertion of an endosurgical electrocautery with irrigation and suction capability (Heartport, Redwood City, CA; or Genzyme Surgical Products, Cambridge, MA) or an ultrasonic scalpel (Harmonic Scalpel, Ethicon Endo-Surgery, Cincinnati, OH). Third, a 3- to 5-mm incision is made in the fourth or fifth intercostal space in the midaxillary line, at the level of the nipple, for insertion of an endosurgical grasper (Heartport; or Mayfield Toothed Grasper, Genzyme Surgical Products, Cambridge, MA) or Kittner dissector (BTD-5, Ethicon Endo-Surgery). Alternatively, the video thoracoscope can be inserted preferentially through the third incision with the working instruments placed in the first and second incisions. Factors that influence incision location include the degree of upper torso obesity, the presence of large breasts, cardiac enlargement, and the location of the anticipated anterior thoracotomy for off-pump coronary bypass. Maneuverability of the working instruments and scope within the pleural cavity can be severely restricted by excessive torque against adjacent ribs and soft tissue. This is ameliorated by introducing instruments directly into the pleural space through small stab incisions without ports (see Fig 1), employing instruments of smaller diameter, interchanging instrument sites (for example, inserting the endosurgical instruments through the caudal two incisions to improve access to the distal LITA), or modifying the intercostal incision. Often, the latter can be accomplished by widening the incision within an intercostal space, or by entering the interspace above or below, through the same skin incision.
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Two hundred eighteen patients underwent thoracoscopic harvest of the ITA at three different institutions (Table 1). The average number of thoracoscopic harvests performed per month at Duke was 7.5 and 2.5 times greater than at the Cincinnati and Atlanta, respectively. This is explained by the policy of routine thoracoscopic LITA harvest in conventional and off-pump coronary bypass cases performed at Duke as part of a larger research investigation. Excluding conventional coronary bypass operations, the average numbers of thoracoscopic harvests performed per month for off-pump coronary bypass grafting at Duke, Cincinnati, and Atlanta were 1.3, 2.7, and 0.9, respectively. The LITA was harvested in 96% of cases. The vast majority of patients had thoracoscopic harvest for primary operations. Patients were 3.5 times more likely to be male than female. This is explained in part by the preponderance of Veterans Administration Medical Center patients included in the Duke series and the institutional bias against performing thoracoscopic harvest in female patients with significant truncal obesity, a short torso, or large breasts.
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This large, multicenter experience demonstrates that thoracoscopic harvest of the ITA can be accomplished safely and within a reasonable time frame in most patients undergoing coronary bypass grafting. Superior exposure of the ITA is achieved by complete collapse of the ipsilateral lung with a bronchial blocker or double-lumen endotracheal tube. After the initiation of single-lung ventilation, a thoracoscope is inserted through a small incision (5 to 10 mm) into the chest and the ITA is inspected. Exposure is improved through judicious use of carbon dioxide gas insufflation, which shifts the mediastinum toward the contralateral lung and the heart away from the anterior chest wall. Relative contraindications to thoracoscopic harvest include extensive pleural symphysis, significant cardiac enlargement, and exuberant mediastinal, pericardial, and chest wall fat. An absolute contraindication is intolerance to single-lung ventilation because of severe pulmonary disease [6]; however, such patients are uncommon and were not encountered in this series. A cutting/coagulating device and a retractor instrument are introduced into the chest through separate small incisions (3 to 5 mm) that permit easy maneuverability and access to the ITA. Meticulous endosurgical technique combined with advanced instrumentation permits harvest of the entire ITA in the vast majority of patients with minimal trauma and morbidity.
For off-pump coronary bypass grafting, thoracoscopic harvest of the internal thoracic artery offers several distinct advantages:
(1) The optics on current endoscopes have achieved exceptional resolution and magnification (up to 20x), providing unsurpassed visualization. Hence, even the most diminutive vessel branches can be identified and controlled with remarkable precision. Indeed, the current study demonstrated a less than 1% risk of reoperation for bleeding secondary to missed branches on the ITA pedicle.
(2) The thoracoscopic approach allows complete harvest of the internal thoracic artery from the first through sixth ribs. This was accomplished in nearly 90% of patients in this series. In contrast to open ITA dissection through a minithoracotomy for off-pump coronary bypass, thoracoscopic harvest consistently provides sufficient pedicle length for a tension-free anastomosis without kinking. In a particularly striking example, McMahon and associates [7] reported on a patient whose short LITA graft (dissected between the third and fifth interspaces through a minithoracotomy) had completely avulsed from the anterior descending coronary artery after a period of heavy lifting. Finally, complete harvest of the entire ITA allows optimal positioning of the pedicle beneath the inflated lung.
(3) Using a thoracoscopic approach, the minithoracotomy incision can be tailored exclusively to facilitate the coronary anastomosis—rather than the ITA harvest—thus, thoracoscopic ITA harvest allows a smaller chest incision. More importantly, rigorous chest wall retraction and cartilage and rib resection are virtually eliminated [6, 8]. In our experience, the chest incision measures only 4 to 6 cm in length, directly overlies the anterior descending coronary artery, and is often centered near the nipple away from the lateral sternal border. These benefits may translate into less postoperative incisional pain, improved pulmonary function, and more rapid recovery.
(4) Thoracoscopic ITA harvest requires fundamental skills that provide the platform on which future advances in endosurgical technology and methodology will build. Thus, thoracoscopic ITA harvest may bring us one step closer to achieving true minimally invasive surgical revascularization.
Although this study clearly establishes the efficacy of thoracoscopic ITA harvest for coronary artery bypass, several potential limitations to the procedure were observed.
(1) Proficiency at thoracoscopic harvest entails a significant learning curve. In particular, for surgeons inexperienced in thoracoscopic techniques, the hand-eye coordination required to accomplish even the most basic surgical tasks may be disconcerting. Moreover, the infrequency of suitable candidates for thoracoscopic harvest when limited to off-pump coronary bypass procedures may further impede training. Indeed, in this study, the average number of thoracoscopic harvests performed for off-pump coronary bypass operations ranged from only 1 to 2.7 cases per month. At present, the ideal mechanism to obtain appropriate instruction and training in thoracoscopic ITA harvest is problematic.
(2) Although the time required for thoracoscopic ITA harvest improved significantly over the course of this study, the procedure is unlikely to require less time than open ITA harvest through a median sternotomy. Among the three participating centers, the average duration of ITA harvest ranged from 42 to 55 minutes. Although the putative benefits of thoracoscopic harvest arguably justify the additional time invested, it is also reasonable to expect that future technical refinements will continue to improve the efficiency of the procedure.
(3) Compared with open ITA harvest through a median sternotomy, the use of disposable items to facilitate thoracoscopic harvest increases cost. In this study, the per procedure cost for disposable items ranged from $155 to $335. Yet, this compares favorably with the inordinate cost of current devices to facilitate less-invasive direct ITA harvest through a minithoracotomy, which ranges from $800 for disposable retractors to upwards of $5,000 for reusable ones.
(4) Thoracoscopic ITA harvest is technically difficult in certain patients. In particular, those with significant upper torso obesity, narrow intercostal spaces, and abundant mediastinal, pericardial, and chest wall fat may present a formidable challenge. Ironically, because these patients are at a high risk for wound complications and significant postoperative incisional pain after open ITA harvest through a minithoracotomy, they stand to benefit the most from a thoracoscopic approach. It is speculated that technical improvements to facilitate thoracoscopic harvest may particularly benefit this subgroup of patients.
(5) Similar to the open technique, thoracoscopic harvest may risk injury to the ITA. In the present study, the prevalence of ITA injury after thoracoscopic harvest was 1.8%. Insofar as the observed rate of ITA injury can be attributed in part to the learning curve, a larger experience is necessary to more accurately determine risk. Furthermore, intermediate- and long-term angiographic follow-up can best establish the risk of occult injury to the ITA after thoracoscopic harvest. Studies attempting to address this important issue are currently underway.
In summary, this large, multicenter experience demonstrates that thoracoscopic harvest of the ITA can be accomplished safely and within a reasonable time frame in most patients undergoing coronary bypass grafting. Although this study clearly establishes the fundamental technique, widespread application of thoracoscopic ITA harvest must await future refinements in endosurgical technology and methodology to address the important issues raised in this report. Finally, provisions for training must be determined so that cardiac surgeons can obtain the fundamental skills necessary to safely perform thoracoscopic ITA harvest, as well as to incorporate new endosurgical techniques as they evolve.
Footnotes
1 Doctor Wolf is a paid consultant for Ethicon Endo-Surgery, Cincinnati, OH. Doctor Mayfield is a paid consultant for Genzyme Surgical Products, Cambridge, MA. 
References
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|
|
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|
|
|
|
|
|
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|
|
|
|
 |
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|
|
|
|
 |
|
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|
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|
|
 |
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
 |
|
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|
|
|
|
 |
|
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|
|
|
|
 |
|
 H. G. Colt Thoracoscopy: Window to the Pleural Space Chest, November 1, 1999; 116(5): 1409 - 1415. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. K. Wolf, K. Miyaji, and J. B. Flege Jr Thoracoscopic mammary artery mobilization in redo minimally invasive coronary bypass operations Ann. Thorac. Surg., October 1, 1999; 68(4): 1540 - 1541. [Abstract] [Full Text] [PDF]
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