Asian Cardiovasc Thorac Ann 2001;9:260-263
© 2001 Asia Publishing EXchange Pte Ltd
Another Autograft for Coronary Artery Bypass Grafting
Wang Wen Lin, MD,
Zeng Wei Sheng, MD,
Jiang Ren Chao, MD
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Department of Cardiothoracic Surgery Guangzhou General Military Hospital Guangzhou, Guangdong People's Republic of China
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For reprint information contact: Wang Wen Lin, MD Tel: 86 20 3622 2315 Fax: 86 20 3622 5230 email: willine0472{at}sina.com Department of Cardiothoracic Surgery, Guangzhou General Military Hospital, No. 111 Liuhua Road, Guangzhou, Guangdong 510010, People's Republic of China.
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ABSTRACT
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To assess the possibility of using the descending branch of the lateral circumflex femoral artery as a free arterial autograft for coronary artery bypass grafting, the anatomy of this artery and its surrounding structures were studied in 19 cadavers. The artery was found to be situated in the groove between the rectus femoris and the vastus intermedius muscles. The mean length of the arterial trunk was 12 ± 2.36 cm (range, 9.2 to 15.1 cm). The diameter was 2.7 ± 0.35 mm at the origin and 2.2 ± 0.28 mm at the terminal end. The reflection of this artery on the body surface was easy to locate. It was concluded that the descending branch of the lateral circumflex femoral artery could be considered as a potential conduit for coronary revascularization.
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INTRODUCTION
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Arterial grafts have been used for coronary artery bypass grafting (CABG) for many years.1 Although numerous arteries in the human body have been found useful for CABG, there are still occasions when these are insufficient.1–3 Thus, identification of other potential arterial grafts is meaningful. The lateral circumflex femoral artery (LCFA) is a branch of the deep femoral artery or the femoral artery, and its descending branch (DBLCFA) is a large blood vessel in the anterolateral part of the thigh. In recent years, the DBLCFA has been widely used as the nutrient artery for femoral anterolateral flaps, and satisfactory results have been claimed.4 However, the use of DBLCFA as a conduit in CABG has not been reported.
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MATERIALS AND METHODS
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All 38 DBLCFA from 19 adult cadavers were investigated. The arterial system of these cadavers was infused with red emulsion. The anatomy of the anterolateral part of the thigh, especially the DBLCFA and its surrounding structures, was studied carefully. The length of the DBLCFA trunk between its origin and the site where it diverged into the vastus lateralis muscle was determined. The outer diameters at the origin and the terminal end of the DBLCFA trunk were measured. The vertical distance from the groove between the rectus femoris and the vastus lateralis muscles to the median point of a line between the anterosuperior iliac spine and the median of the patella was ascertained (Figure 1
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Figure 1. Reflection of the descending branch of the lateral circumflex femoral artery on the body surface and its surrounding structures. A = femoral artery, B = ascending branch of the lateral circumflex femoral artery, C = transverse branch of the lateral circumflex femoral artery, D = anterosuperior iliac spine, E = median of the patella, F = origin of the descending branch of the lateral circumflex femoral artery, G = site of divergence of the descending branch of the lateral circumflex femoral artery into the vastus lateralis muscle.
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The DBLCFA was harvested by initially drawing a line from the anterosuperior iliac spine to the median of the patella and locating its median point. A longitudinal skin incision was made 0.5 cm exterior to the median point, approximately 5 cm in length. The subcutaneous tissue was dissected until the fascia lata was encountered. The fascia lata was incised longitudinally and blunt dissection was used to expose the groove between the vastus lateralis and rectus femoris muscles. The incisions in both the skin and the fascia lata were extended upwards along the course of this muscular groove, until the groove could be exposed adequately. The groove was retracted as widely as possible. When the neurovascular bundle was located, its fascia was cut longitudinally. The accompanying nerve was dissected to free the DBLCFA and its branches. After careful examination of the vessel, all its branches were ligated and dissected, and the trunk of the DBLCFA and its accompanying veins were harvested. In the clinical situation, the fascia lata and skin incisions could then be sutured after reliable hemostasis.
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RESULTS
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In most cases (34/38; 89%), the LCFA arose from the deep femoral artery, and only 4 of these arteries arose from the femoral artery. The LCFA was noted to give off ascending, transverse, and descending branches in 6 configurations (Figure 2). Type I (11/38; 29%) and type II (13/38; 34%) were the most common configurations encountered. After the ascending and transverse branches emerged near its origin, the LCFA was found to advance exteriorly at first, and then descend from the interior superior to the exterior inferior region. This part of the LCFA has been defined as the DBLCFA. In the upper part of its course, the DBLCFA was seen to be situated in the groove between the rectus femoris and vastus intermedius muscles before descending into the groove between these muscles. The accompanying structures, including a couple of veins and the nerve to the vastus lateralis muscle, were observed to be wrapped in a layer of fascia. During its descending course, the DBLCFA was perceived to give off some branches into the vastus medialis, rectus femoris, and vastus lateralis muscles. It was determined that the trunk of the DBLCFA diverged into the vastus lateralis muscle, and its terminal portion proceeded downwards to the exterior superior part of the knee, and contributed to an arterial network.
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Figure 2. Configurations of the origin of the descending branch of the lateral circumflex femoral artery.
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The mean length of the DBLCFA trunk was 12 ± 2.36 cm (range, 9.2 to 15.1 cm), and the diameters at its origin and terminal end were 2.7 ± 0.35 mm and 2.2 ± 0.28 mm, respectively. On the body surface, the reflection of the DBLCFA trunk was situated in the mid superior part of the front of the thigh, which was interior and superior to the reflection of the superior half of the groove between the rectus femoris and lateralis muscles. The vertical distance from this groove to the median point of the line drawn from the anterosuperior iliac spine to the median of the patella was 0.4 ± 0.18 cm (Figure 1
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DISCUSSION
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Since the internal thoracic artery was first used as a graft for CABG, several other arteries have been employed as conduits, including the radial, inferior epigastric, inferior mesenteric, and right gastroepiploic arteries.5–9 In spite of the substantial number of arteries potentially available for grafting, sometimes the requirements for CABG are not met in cases of extensive arterial disease.2,3 Coronary artery disease usually involves more than one vessel, so several grafts may be needed for complete revasculari-zation. Unfortunately, postoperative progression of disease in the native coronary arteries and obstruction of the bypass grafts are not uncommon, but reoperation for further grafting requires additional conduits. Moreover, the frequent involvement of arteriosclerosis in some potential arterial grafts makes these vessels unsuitable for use in CABG. In such circumstances, it is desirable to find other available arteries that could be employed for coronary revascularization.
A satisfactory arterial autograft should be attributed with certain essential features.2,3 First, it should have an adequate length and diameter. On removal for use as a free graft, there should be sufficient collateral circulation to supply nutrients to its associated organ or tissues. It should have a regular and superficial course to facilitate its location and harvesting. In addition, there should be no important structures in the surrounding area, which could pose a danger during conduit harvesting.
When CABG is performed between the ascending aorta and a coronary artery, the length of the graft required may be estimated from the following guidelines: 12 to 15 cm for the distal third of the right coronary artery; 15 to 18 cm for the posterior descending artery; 10 to 15 cm for the left anterior descending artery, depending on the level of anastomosis; 10 to 15 cm for the first obtuse marginal artery; and 20 cm for the posterolateral artery.10 As no comparative experiments were performed, it is difficult to assess the length of the DBLCFA in relation to these distances. Nevertheless, it is obvious that the length of the DBLCFA trunk could meet the requirements for bypass of some coronary arterial branches. It would most certainly fulfil the criteria for bypassing the left anterior descending artery and the first obtuse marginal artery, although it might not be suitable for the posterior descending and posterolateral arteries. However, if the bypass was carried out as a Y-graft or T-graft from the left internal thoracic artery to the posterior descending and posterolateral arteries, use of the DBLCFA could be extended.10 The outer diameters of the origin and terminal end of the DBLCFA trunk were similar to the diameters of the major coronary arteries. Thus, the width of the DBLCFA is adequate for a satisfactory blood flow, and the com-patibility of widths would also facilitate the anastomosis.4
The DBLCFA has long been used as the nutrient artery in anterolateral flaps, and it has been demonstrated clinically that all the structures nourished by this branch have abundant collateral circulation.4 If the DBLCFA was dissected, all of these structures would still have sufficient blood supply. Therefore, there should be no concern about ischemic complications in the thigh due to removal of the DBLCFA.
Although there were various types of branching at the origin, the course of the DBLCFA observed in this study was relatively uniform. Thus, it should be easy to find and dissect this artery through the groove between the vastus lateralis and rectus femoris muscles. Furthermore, the accompanying nerve of the LCFA was easy to dissect from this artery, and the accessory veins could be removed simultaneously.
As harvesting of the graft in CABG is an affiliated operation, it should be as simple as possible, and it should not cause extensive tissue injury. The operation of harvesting a femoral anterolateral flap has been performed for many years. However, its purpose is not just to obtain an arterial conduit. Thus, the damage is relatively wide, and this harvesting method is not suitable for procuring a graft for CABG.4 After carefully studying the anatomical characteristics of the DBLCFA, the harvesting method described herein was developed for use in coronary revascularization. With a lateral thigh incision, it is easy to enter the groove between the vastus lateralis and rectus femoris muscles, and very simple to expose and remove the DBLCFA.
Nevertheless, there are some limitations on the use of the DBLCFA. During harvesting, insufficient length of the DBLCFA trunk might be encountered. In this circumstance, several strategies could be considered to deal with the problem. First, it could be dissected downwards into the vastus lateralis muscle until an adequate length was achieved. Second, if the distal part of the DBLCFA trunk was not wide enough for CABG, a segment of the ascending or transverse branch of the LCFA could be removed and anastomosed end-to-end with the DBLCFA to obtain a satisfactory graft. Third, if the DBLCFA has a very short trunk and its terminal end gives off 2 branches, the short trunk and its slender branches could be removed at the same time; the 2 branches could then be anastomosed simultaneously to one coronary artery in an end-to-side fashion. Besides these limitations of the DBLCFA, there are some potential complications in the harvesting procedure, as with any other arterial graft. These complications include possible damage to the femoral structures and postoperative infection. Fortunately, both of these can be avoided by a careful harvesting procedure and prudent postoperative management. Since atherosclerosis can involve every part of the arterial system, there is the possibility of obstruction of the DBLCFA. Therefore, to avoid an unsuccessful harvesting attempt, some preoperative investigations such as a Doppler sonogram or arteriography should be made.
It was concluded from these data that the DBLCFA could be regarded as a potential conduit for CABG. If investigated carefully preoperatively and harvested skilfully, this vessel could provide a satisfactory arterial autograft. As these studies, especially the harvesting procedure for DBLCFA, were carried out in cadavers, some details should be further assessed before clinical application.
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REFERENCES
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ABSTRACT
INTRODUCTION
