Interact CardioVasc Thorac Surg 2005;4:160-162. doi:10.1510/icvts.2004.104828
© 2005 European Association of Cardio-Thoracic Surgery
Institutional report - Coronary |
Endothelium histological integrity after skeletonized dissection of the left internal mammary artery with ultrasonic scalpel
Pedro P. Lima Cañadas1,*,
Alfonso Cañas Cañas1,
Juan L. Orradre Romeo2,
Carlos I. Rubio Martínez2,
Luis F. López Almodóvar1 and
Manuel Calleja Hernández1
1 Departments of Cardiac Surgery, Hospital "Virgen De La Salud", Servicio de Cirugia Cardiaca, Avenida de Barber 30, 45005 Toledo, Spain
2 Departments of Pathology, Hospital, "Virgen De La Salud", Toledo, Spain
Received 19 December 2004;
received in revised form 17 February 2005;
accepted 1 March 2005
 Presented at the joint 18th Annual Meeting of the European Association for Cardio-thoracic Surgery and the 12th Annual Meeting of the European Society of Thoracic Surgeons, Leipzig, Germany, September 12-15, 2004.
*Corresponding author. Tel.: +34 609955315; fax: 34 925269499 (upon request).
E-mail address: plima{at}sescam.jccm.es (P.P. Lima Cañadas).
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Abstract
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Evaluate the endothelium histological changes produced in the left internal mammary artery (LIMA) after its dissection in a skeletonized manner with an ultrasonic scalpel. Two study groups were created in a prospective and randomized way: group A, 14 LIMA fragments skeletonized with a high frequency ultrasonic scalpel and group B (control group) with 14 specimens dissected with scissors and clips. The endothelium was studied in all 28 fragments fixing the segments with 10% formaldehyde, and paraffin inclusion. The arteries were sliced in 4 µm sections and stained with hematoxilin-eosin, and then evaluated by one single pathologist. In group A (ultrasonic scalpel) none of the specimens showed any endothelial damage, as did the samples in group B (control group). In both groups the endothelial wall was intact. There were chronic lesions in the form of intimal hyperplasia that might be in relation to the advanced age of both groups of patients. The left IMA dissection in a skeletonized fashion with an ultrasonic scalpel does not produce endothelial structural damage in it being similar to the one dissected with conventional methods. This permits its safe use, allowing us to benefit from the numerous advantages of arterial grafts usage in modern era coronary surgery.
Key Words: Coronary artery bypass surgery; Internal mammary artery; Surgical instruments
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1. Introduction
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The use of left internal mammary artery (LIMA) to the left anterior descending artery has been associated with increased survival in patients undergoing coronary artery bypass grafting when compared to vein grafting [1]. This conduit can be used in a pedicle, skeletonized and free form [2]. There are several reports indicating the advantages of having the LIMA dissected in a skeletonized manner, as far as sternal blood supply and length of the obtained graft [3].
Several authors have clearly stated the possibility of LIMA damage when harvested with electric scalpel thus altering the fate of the conduit [4]. The broader availability of the harmonic scalpel (Ultracision Ethicon corp., Michigan) has led some groups to use this device for LIMA harvesting with early state reports in experimental and clinical data [5,6].
The objective of the study was to evaluate the histological damage produced with the harmonic scalpel to the LIMA compared with the classic dissection with scissors and clips when obtaining the conduit.
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2. Patients and methods
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Twenty-eight consecutive patients submitted to our institution for isolated coronary artery bypass grafting between October and December 2003 were enrolled in the study. Informed consent was obtained from all the participants and the ethical committee from our hospital approved the study. These patients were prospectively randomized to have the final portion (1–2 cm) of the LIMA dissected with either ultrasonic scalpel or scissor and clips dissection.
In all cases a median sternotomy was performed. After careful dissection of the pleural reflection the LIMA was exposed. The internal thoracic fascia was opened with the ultrasonic scalpel and the fat around the artery mobilized with the ‘fast touch’ technique described in detail by Higami and coworkers [7]. The branches were coagulated 1 mm away from the main trunk and the final portion of the artery was dissected according to the randomization group either with ultrasonic scalpel or scissor and clips. The artery was soaked in papaverin and no intraluminal drugs were administered [8].
The fragments were placed in saline solution and sent to the pathology lab to be processed. They were included in 10% formaldehyde and then included in paraffin. They were cut into 4 µm sections and stained with the usual hematoxilin-eosin procedure.
The sections were evaluated by one single pathologist (JL Orradre) and carefully inspected for endothelial layer disruption and basal membrane exposure and for thrombi formation.
All the clinical preoperative data and the histological result were included in a database and processed statistically with the Openstat 3.5.6 (William G Miller, Iowa, USA).
The clinical preoperative data are presented in Table 1. There were no statistically significant differences in any of the risk factors evaluated for both groups.
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3. Results
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None of the samples in the Ultracision group showed any endothelial disruption or exposure of the basal membrane. There was some evidence of intimal hyperplasia which is considered to be a chronic lesion probably related to age. An example of both groups is shown in Fig. 1. There were no damage cases in control group.
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4. Discussion
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The LIMA graft to the anterior descending artery has been clearly stated as the sole major determinant of short and long term results for the coronary bypass surgery [1]. The most actual patency data for the LIMA is 96.4% at 79.3 months in a series with 1345 grafts from the series by Tatoulis and coworkers [9].
The damage that the LIMA may sustain during harvesting and manipulation prior to grafting has been associated with early graft failure with intraluminal thrombi formation, and also with initiation of the inflammatory cascade that may lead to intimal hyperplasia and late graft failure.
There are three modes of LIMA use in coronary surgery which are free grafts, pedicle grafts and skeletonized grafts. Free grafts have been shown to have lower patency rates than pedicle grafts and several factors have been invoked [10–12]. These factors include the discontinuity of an elastic artery with a low calibre artery, and the pulsatile flow in the aorta.
The comparison between pedicle and skeletonized grafts have been discussed by many authors and recently summarized in a meta-analysis by Athanasiou et al. [3]. There is an increase in the preservation of sternal blood supply in the skeletonized group and also a higher free flow. The patency rates for skeletonized arteries are similar to the pedicle group. There were no clinical differences in any of the settings even in diabetic patients.
The different methods of skeletonized dissection include the standard method of scissor and clips, electrocautery and ultrasonic scalpel.
The original technique for dissection of the LIMA with ultrasonic scalpel was described by Higami and co-workers and they have evaluated the safety of their technique for side branch closure and recently published their initial clinical results with excellent patency rates [5–7]. Yoshikai et al. have confirmed the safety of the method with a scanning electron microscope analysis [13].
Lehtola and coworkers raised the question about the safety of electrocautery use for LIMA harvesting [4], and other authors have stated that a lower damage rate was achieved when an ultrasonic scalpel, compared to electrocautery in pedicles smaller than 0.5 cm was used [14]. The only three arms comparison showed lower clip use for the ultrasonic group with no significant differences between groups [15].
Our study shows the feasibility and safety of LIMA harvesting with the ultrasonic scalpel and it has become our routine practice.
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5. Conclusions
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The left IMA dissection in a skeletonized fashion with an ultrasonic scalpel does not produce endothelial structural damage in it being similar to the one dissected with conventional methods. This permits its safe use, allowing us to benefit from the numerous advantages of arterial grafts usage in modern era coronary surgery. We recommend its routine use for LIMA harvesting in a skeletonized manner.
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References
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Abstract
1. Introduction
