A review of the best method of leg wound closure following open harvesting of the long saphenous vein for coronary artery bypass grafting

Uncertainty exists around the optimal method of leg wound closure following open long saphenous vein harvesting in adults undergoing coronary artery bypass graft surgery (CABG). Such is evident from the variety observed in the closure approach utilised. Consequently, a best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was ‘following open long saphenous vein harvesting in adults undergoing CABG, is single-layer leg wound closure superior to multiple-layer closure in terms of post-operative complications encountered? ‘. Altogether 382 papers on Ovid Embase and Ovid Medline, 301 papers on PubMed and 11 papers on the Cochrane database were found using the reported search. From the screened articles, 6 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that the best method of leg closure following open saphenous vein harvesting for CABG is single-layer cutaneous closure. The use of a suction drain to eliminate the dead space should be considered on a case-to-case basis by the lead operating surgeon with the patient's characteristics and their own expertise in mind.


Introduction
Leg wound complications following coronary artery bypass graft surgery (CABG) are a major cause for morbidity requiring further invasive interventions [1]; a large-scale study by Paletta et al. reported an average lower extremity complication rate of 4.1% which conforms with the range observed in other literature findings [1][2][3][4]. As such, it is important to study every surgical aspect to identify methods of minimising the complication rate where possible in addition to making economic and time savings. Endoscopic vein harvesting of the long saphenous vein (LSV) is gaining popularity over the open approach owing to its lower complication rate [5]; however, several centres continue to use the open technique due to factors such as the harvest time, learning curve and cost. In this study, we have focused on the open technique. Traditionally, when employing the open approach to harvesting the LSV as a conduit for CABG, a double-layer closure technique is used where the subcutaneous tissue is closed first followed by cutaneous closure. Here, we review the best evidence available to determine whether the multiple-layer approach should be replaced by a single-layer cutaneous closure. This best evidence topic was constructed according to a structured protocol; this is fully described by the International Journal of Surgery [6].

Clinical scenario
A 74-year-old patient with a background of type 1 diabetes mellitus initially presented to the chest pain clinic with angina. Further investigations were carried out including percutaneous angiography which revealed severe triple vessel disease of the coronary arteries. Echocardiography found no valvular pathology and a left ventricular ejection fraction of 30-35%. The case was discussed at the multidisciplinary meeting and CABG was recommended. You discuss the choice of conduit with the patient. The patient who is of a surgical background enquires further about the outcomes encountered when using a single-layer leg wound closure compared with multiple-layer closure. Unsure of the best closure technique, you resolve to check the literature for evidence.

Three-part question
In [adults undergoing coronary artery bypass graft surgery], which method of leg wound closure following open long saphenous vein harvesting [single-layer versus multiple-layer closure] is superior in terms of [length of admission and post-operative complications] encountered?

Search strategy
The search strategy outlined below was utilised and where possible the results were limited to English articles, Persian articles and human studies. In addition, the reference lists of the screened articles were reviewed. Medline

Search outcome
382 papers on Ovid Embase and Ovid Medline, 301 papers on PubMed and 11 papers on the Cochrane database were found using the reported search and screened. From these, 6 papers were identified that provided the best evidence to answer the question determining the optimal leg wound closure technique following open LSV harvesting in adults undergoing CABG. These are presented in Appendix 1. An example of the screening and eligibility assessment process for the search results obtained from the Ovid interface is detailed in Fig. 1.

Results
The results of this article are tabulated in Appendix 1 which contains a review of the most relevant and highest quality evidence available assessing the best method of leg wound closure after harvesting the LSV for CABG. This table is structured according to the guidance by the International Journal of Surgery [6] highlighting key results, statistical analysis and study limitations.

Discussion
In 2011, a randomised controlled trial by Siddiqi et al. compared single-layer closure of the leg over a suction drain (with drain removal after 48 hours) against double-layer closure following extraction of the LSV for CABG [7]. The harvesting of the vein was performed by a single surgeon and the patients were followed up until two weeks after discharge. The ASEPSIS score was used to assess the wound in this study; this scoring method was first described in a study published in the Lancet by Wilson et al. on cardiac surgery patients [8] and has been shown to be a reliable method of wound assessment [9]. The ASEPSIS score allocates points for the following: need for Additional treatment, Serous discharge, Erythema, Purulent exudate, Separation of deep tissues, Isolation of bacteria, and the duration of inpatient Stay. In the study by Siddiqi et al. the mean ASEPSIS score of both single-and double-layer groups were within the satisfactory healing category; however, a statistically significant lower ASEPSIS score was observed in the single-layer group compared with the double-layer group. Furthermore, a smaller percentage of complications were encountered in the single-layer group. Consequently, it was concluded that single-layer closure of the leg wound should be the method of choice.
Tiryakioglu et al. conducted a randomised controlled trial in 2010 comparing single-layer closure with double-layer closure following saphenectomy for CABG [10]. Several aspects of the leg wound were assessed up to 2 months post-operatively. There were no statistically significant differences between the two groups in terms of the demographics, operative time, number of grafts and hospitalisation period. Whilst it was found that up to the point of 1 week post-discharge, the incidence of haematoma was higher in the single-layer group, this was not statistically significant. On the other hand, the single-layer group demonstrated a statistically significant lower incidence of infection, oedema, numbness and number of legs with associated complaints. As such, it was reasonably concluded that single-layer closure should be the favoured method.
In 2006, a randomised controlled trial by Stenvik et al. investigated single-layer leg wound closure against double-layer closure and further investigated the impact of the operating practitioner harvesting the vein (rotational surgical residents against one dedicated experienced physical assistant) [11]. Whilst a lower incidence of infection was observed in the single-layer group, this was not statistically significant. Of note is the fact that there was a significant lower infection rate in the group operated on by one dedicated physical assistant when compared to the group operated on by surgical residents. In terms of closure technique, similar findings were reported in a study by Teebken et al. who observed no significant difference between the two closure methods when considering haematoma formation, length of hospital stay, infection and wound dehiscence; this article by Teebken et al. has not been tabulated in the present study because it is not available in English [12].
Zafar et al. conducted a randomised controlled trial in 2005 to compare single-layer leg closure over a suction drain (with drain removal after 24 hours) against double-layer closure following saphenectomy for CABG [13]. The legs were reviewed every 48 hours until discharge and at 6 weeks in the outpatient clinic. The randomisation method of minimisation and the statistical analysis are clearly defined. The ASEPSIS score, used to assess the wound in this study, suggested satisfactory wound healing in both the single-layer and double-layer group. However, keeping in mind that a lower ASEPSIS score indicates a better outcome, the single-layer group had a statistically significant lower ASEPSIS score; this finding was maintained when the diabetic and non-diabetic subgroups were analysed separately. Considering the statistically significant lower ASEPSIS score and incidence of donor leg oedema as well as the quoted decreased dead space due to haematoma evacuation and reduced tissue handling, the single-layer technique of leg wound closure with a drain was determined to be the superior method.
A randomised controlled trial by Nouraei et al. in 2010 concluded that single-layer closure of the LSV donor site with a haemovac drain is superior to multiple-layer closure in several aspects at day 2, 14 and 21 post-CABG [14]. The study was limited to those who were non-urgent, BMI less than 30, under 70 years of age and non-diabetic patients. The authors specify that the multiple-layer closure was achieved by closing the "skin, subcutaneous tissue, subcutaneous fat and scarpa's fascia". On day 2 post-operatively, the only statistically significant difference was observed in the lower occurrence of haematomas in the single-layer group. Throughout the following two timepoints, there was a statistically significant lower occurrence of all complications in the single-layer group, apart from saphenous nerve paraesthesia on day 14 and day 21 as well as skin necrosis on day 21 whereby the lower occurrence of these complications in the single-layer group was not statistically significant.
In contrast, a study by Nair et al. assessing the cutaneous sensation in a randomised controlled trial (n = 50) comparing single-layer interrupted sutures without a drain to multiple-layer closure, excluding those with diabetes and peripheral arteriopathy, found less neurological complications and better sensory perception recovery in the single-layer closure group [15]. Apart from gender, no other demographics were disclosed. Wound infection or seroma was not observed in either group. Three patients were excluded due to injury to the branches of the long saphenous nerve. The lower incidence of anaesthesia, paraesthesia and pain in the single-layer group was statistically significant at 1 and 6-8 weeks post-operatively, but not at day two. There was also a lower incidence of neurologic complications in the single-layer group at 14-18 months, though this was not statistically significant. The observed neurological differences were attributed to nerve compression secondary to the subcutaneous sutures.
A randomised controlled trial by El Gamel et al. in 1994 compared single-layer closure against double-layer closure following saphenectomy for CABG [16]. In the first subset, the patients were recruited from the UK and the LSVs were harvested from below the knee of both legs of the same patient; therefore, the patient acted as their own control whereby one leg was randomly assigned to a fat stitch (double-layer closure) and the contralateral leg of the same patient to no fat stitch (single-layer closure). In the second subset, the patients were recruited from the USA and the LSV was harvested from the thigh of one leg (above the knee). Wounds were observed until discharge and later reviewed in the outpatient clinic. The interesting approach for the first subset was unique to this study allowing for controlling of several confounding factors except unequal peripheral arterial disease and such patients were appropriately excluded. However, an explanation is not provided as to why this approach was not used for the second subset. El Gamel et al. concluded that double-layer closure takes longer and may increase skin edge necrosis requiring plastic surgical intervention. Considering the surgical time and comparable complication (Haematoma/infection) rate between single-and double-layer closure, it was suggested that the use of a fat suture is not necessary and as such its use should be discontinued.
The discussions of this study are limited by the weaknesses of the included articles which are highlighted in the comments section of the table in Appendix 1. For instance, it is important to note that the inconsistency in wound healing descriptors makes comparisons between studies more challenging. The ASEPSIS scoring system has been validated as a reproducible method to quantify wound healing and is recommended for future studies in this field.

Clinical bottom line
Taking into account the above discussed articles representing the best evidence topics available, it is evident that the best method of leg wound closure following LSV harvesting for CABG is single-layer cutaneous closure. Some of the discussed studies combined single-layer closure with the use of a suction drain; as such, the use of a suction drain to eliminate the dead space should be considered on a case-to-case basis by the lead operating surgeon with the patient's characteristics and their own expertise in mind.

Ethical approval
Not required.

Funding
None.

Consent
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Registration of research studies
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Declaration of competing interest
None to declare.   Minimisation was used to allow for a method of randomisation which accounts for the imbalance between patients. The statistical analysis method is clearly delineated. No declaration of conflict of interest. Discrepancy in the gender of patients was present (67 male and 11 female patients), but diabetics were equally distributed amongst the two groups. The above discussed discrepancies may be a source of selection bias in this study. NB. a lower ASEPSIS score indicates better healing.