Ann Thorac Surg 1999;67:632-634
© 1999 The Society of Thoracic Surgeons
Original Articles
Minimally invasive internal thoracic artery harvest: the hybrid approach
Massimo Massetti, MDa,
Gerard Babatasi, MD, PhDa,
Patrick Nataf, MDa,
Satar Bhoyroo, MDa,
Olivier Le Page, MDa,
Andre Khayat, MDa
a Thoracic and Cardiovascular Surgery, University Hospital, Caen, France
Accepted for publication July 28, 1998.
Address reprint requests to Dr Massetti, Department of Thoracic and Cardiovascular Surgery, C.H.U. "Cote de Nacre," 14033 Caen, France
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Abstract
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Background. Safe harvesting of the left internal thoracic artery is a difficult problem during minimally invasive coronary artery bypass grafting without cardiopulmonary bypass. A complete internal thoracic artery dissection through a limited approach is technically demanding and time consuming and different techniques have been proposed.
Methods and Results. Based on our experience, the different surgical approaches and technical considerations are reviewed.
Conclusions. A hybrid technique using dissection under direct vision and completed by thoracoscopy is discussed and proposed as our preferred technique of internal thoracic artery harvesting.
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Introduction
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Minimally invasive direct coronary artery bypass grafting (MIDCABG) is a safe and effective procedure with good early and mid-term clinical results, especially with left internal thoracic artery–left anterior descending (LITA-LAD) grafting [1–4]. In these operations there are two fundamental steps: first, an adequate length of ITA must be harvested and second, a technically perfect ITA to LAD anastomosis must be performed on the beating heart. Many surgical approaches with different techniques have been adopted successfully and although anterior minithoracotomy seems to be the most popular approach, the technique of ITA harvesting is still debated [3, 5, 10, 11]. Complete thoracoscopic dissection or preparation under direct vision, either complete or segmental, is discussed. Techniques and approaches are shown in Figure 1. Our clinical experience with MIDCABG during a 15-month period form the basis of this report, which describes the surgical aspects of ITA harvest and the special instruments designed for optimized thoracic access.
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Fig 1. Surgical approaches and techniques of internal thoracic artery harvesting used in minimally invasive direct coronary artery bypass grafting.
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Material and methods
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Between February 1996 and June 1997, 30 patients (18 men and 12 women; mean age, of 67 ± 10 years) were operated for LITA-LAD anastomosis with a MIDCABG approach. The indication of this procedure included proximal disease in the LAD. In most patients percutaneous transluminal coronary angioplasty was either not feasible (due to tight or complex lesions) or unsuccessful. All patients agreed and gave informed consent. Anesthetic management included routine cardiac anesthesia with etomidate, fentanyl, pancuronium bromide, and sodium thiopentale. During the procedure, heparin was administered with a dose of 100 IU/kg body weight. Depending on the bleeding tendency in the operative field, protamine was given to antagonize half of the initial heparin dose.
Only details of the surgical approaches and techniques of ITA harvest were collected and analyzed.
Techniques of ITA harvest changed from a videothoracoscopic dissection to a preparation under direct vision. The surgical approach changed also from the mediastinotomy to the anterior minithoracotomy with or without costal dislocation. On the basis of our experience, the essential points of the different techniques are listed in Table 1.
Thoracoscopic internal thoracic artery harvest
Anterior minithoracotomy
The patient is placed in the 30-degree anterolateral position with the left arm positioned lateral to the chest. The operation is carried out under general anesthesia with single lung ventilation, using a double-lumen endotracheal tube to permit the collapse of the left lung. The left groin was usually draped for potential femoral cannulation. A standard 10-mm 30-degree right thoracoscope is placed through a trocar placed in the fifth intercostal space in the anterior axillary line. Additional ports are placed in the fourth and sixth intercostal spaces along the medial axillary line allowing the introduction of various minimally invasive surgical instruments. After the exploration of the thoracic cavity the LITA is identified and exposed; the pedicle harvesting is performed under video-imaging with control of the side branches by either cautery or endoscopic clips. An electric cautery instrument with a fine spatula tip, which has the ability to both aspirate and irrigate (modified Surgiwand II; U.S. Surgical Corp, Norwalk, CT) allows dissection of the pedicle from the parietal pleura. Fine endoscopic dissectors (Endodissect 176645; U.S. Surgical) permit the manipulation of the pedicled artery without injury. Perforated arterial branches are cauterized or clipped with a thoracoscopic stapler (Endoclip M 176619; U.S. Surgical). This procedure allows complete dissection of the LITA from the subclavian artery to the fifth intercostal space. Distal transection of the LITA is then performed with endoscopic scissors between two vascular clips.
Harvest under direct vision
Anterior mediastinotomy
The patient is positioned in a supine position and intubated with a double-lumen endotracheal tube for selective ventilation on the right lung; the patient is draped as for a conventional coronary bypass procedure, therefore, should any event occur that is not controlled by the usual therapeutic interventions, conversion to classic sternotomy is immediately possible. After an 8- to 10-cm left vertical parasternal incision is made, two costal cartilages (third and fourth) are removed; care is required medially during the excision of the costal cartilage to avoid injury to the underlying ITA. The initial medial and lateral mobilization of the pedicle is particularly difficult and its release from the adjacent intercostal muscles is made without diathermy. Transection and hoisting up the cartilage immediately rostral to the incision improves access for the pedicle takedown. Perforator arterial branches, anterior intercostals, and sternal branches are clipped and cut with fine scissors. Blunt dissection using a small cautery spatula with a protected diathermy tip is used to separate the pedicle from the intercostal muscles and from the endothoracic fascia. As freeing of the pedicle progresses, the dissection becomes easier and it can be taken right to the origin from the subclavian artery and distally just one interspace beyond the lower margin of the incision. If necessary, the internal thoracic vein can be clipped and severed to obtain more ITA length. The intercostal branch in the first interspace is usually only clipped. Once the ITA has been transected distally, the entire pedicle is mobilized and further hemostasis of the vascular bed is accomplished if needed.
Anterior minithoracotomy
The patient’s position and preparation for operation are the same as for thoracoscopic harvesting of the ITA. A 10- to 12-cm submammary incision is made over the fourth interspace; the pleura is opened and the lung is pushed away by a gauze pad. An ITA access retractor (Thora-LIFT Rib Retractor System; U.S. Surgical) is placed and the fourth and fifth ribs are offset, creating a wide tunnel for ITA dissection. The mobilization of the entire pedicle of the ITA is done from a lateral approach, resulting in a mirror image of the technique used in median sternotomy. The retractor hoists the anterior thoracic wall and in patients with narrow intercostal spaces or fragile ribs, the intercostal muscle is detached from the rib 4 to 6 cm lateral to the skin incision to increase the mobility of the ribs and reduce the risk of fracture. The ITA pedicle is harvested under direct vision proximally, usually to the first and sometimes only to the second rib in tall patients. The assistant maneuvers the inferior blade of the retractor upward to elevate the inferior ribs and maximize the exposure. The ITA is dissected distally to the sixth rib and if possible the sixth intercostal space. To minimize the trauma to the ITA during harvest and thereby minimize spasm, hydrostatic pressure is applied as an aid to dissection of the tissue.
After a line is marked superficially with the diathermy 1 cm lateral from the ITA, a syringe containing papaverine solution with a fine metal cannula is introduced through this region so that its point is immediately between the costal cartilage and the adjacent tissue. Ten milliliters of this solution is injected with the effect that the ITA pedicle is separated from the costal cartilages and from the diathermy tip during the dissection. This method, previously experienced during a sternotomy approach, enables easy dissection of ITA through a small minithoracotomy minimizing the trauma to the pedicle and preventing its spasm [6].
The hybrid technique
A small anterior thoracotomy with a 6- to 8-cm skin incision and without costal dislocation permits a video-assisted harvesting of the ITA pedicle. At the beginning, an endoscopic approach allows for dissection of the proximal part of the ITA; the cranial segment of the artery is easily mobilized from the endothoracic fascia and the branches are ligated with hemostatic clips or dissected with electrocautery. The distal part of the ITA is usually intramuscular and frequently covered by pleuropericardial fat. Moreover, the increased cardiac volume sometimes makes it difficult to harvest this portion of the artery thoracoscopically; therefore, a dissection under direct vision is performed through the limited anterior thoracotomy without any costal dislocation or fractures. A platform thoracic retractor (Thora-Lift Rib Retractor System, U.S. Surgical) with a 5-cm retractor blade and "kick-stand" legs are especially designed to improve access for ITA dissection; by elevating the third and fourth ribs, and depressing the first and second ribs, it maximizes the exposure without excessive trauma to the thoracic wall. The thoracoscopy is used as source of intrathoracic light. Special adapted instruments like the electrocautery instrument with a 10-cm long tip and a disposable instrument (Endo-peanut 173019, U.S. Surgical) facilitates the dissection of the entire pedicle (Fig 2 ).
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Fig 2. Hybrid technique: operative view. After the proximal internal thoracic artery has been harvested by thoracoscopy; the distal segment is being dissected under direct vision through a limited anterior thoracotomy.
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Comment
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Early reports questioned the most simple and effective approach in MIDCABG [1, 7–9]. In this operation a safe harvest of the ITA precedes coronary anastomosis on a beating heart. Although many surgeons perform MIDCABG through a ministernotomy or parasternal longitudinal thoracotomy, actually the most popular approach for minimally invasive coronary operations remains the anterior minithoracotomy with or without costal resection or dislocation [3, 5, 8–10]. The fundamental steps of this operation range from complete endoscopic dissection to a totally open technique under direct vision [3, 6, 10, 11] . Although the former approach is likely to be least traumatic, it is technically demanding and time consuming. Therefore, a practical compromise seems to be a "video-assisted" approach whereby the left ITA is dissected under direct vision and sometimes helped by thoracoscopy; the instruments are introduced through the minithoracotomy and the surgeon can work in a manner not so different from the classic sternotomy approach. The advantages of this approach are that it is quick, does not require special instruments, and does not require previous experience in endoscopic surgery. In a number of surgical specialties, simple reduction in the size of incisions has resulted in reduced trauma and accelerated patient recovery. Nevertheless sometimes minimal access techniques do not necessarily equate with minimal trauma. If the costal cartilage has to be resected or dislocated or the rib cage hoisted up for exposure to compensate for the limited incision, the purpose of minimal access operation is defeated. It is well known that in thoracic operations the main cause of postoperative pain and morbidity is the spreading of ribs and sternum, and not the size of the skin incision. The hybrid technique of harvesting ITA appears in our experience a practical compromise between surgical exposure and less invasive operation. It is quick to execute, the learning curve for the surgeon is acceptable, and it does not inflict unnecessary trauma to the chest wall.
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Acknowledgments
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We sincerely appreciate and acknowledge our anesthesiologists for their continuous support to our work. We also recognize Lecornu Gerard for the technical assistance. This work was made possible by the economic support of Groupement d’Etudes et de Recherche en Chirurgie Cardiovasculaire.
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Abstract
Introduction
