Ann Thorac Surg 2006;81:1269-1274
© 2006 The Society of Thoracic Surgeons
Original article: Cardiovascular
Selection of Saphenous Vein Conduit in Varicose Vein Disease
Joseph D. Cohn, MD, FACS
*
,
Keith F. Korver, MD, FACS
Department of Surgery, Sutter Medical Center of Santa Rosa, Santa Rosa, California
Accepted for publication November 4, 2005.
* Address correspondence to Dr Cohn, 5773 Shiloh Ridge, Santa Rosa, CA 95403 (Email: jcohn{at}alum.mit.edu).
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Abstract
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BACKGROUND: Limbs with varicose veins are difficult to assess as a source of saphenous vein conduit. Anatomic, histologic, and ultrasound studies demonstrate two types of longitudinal veins in the lower extremities. The great saphenous vein is deep to the saphenous fascia. Accessory saphenous veins are superficial to this layer and have thin walls with diminished muscle cells and elastic fiber. Accessory saphenous veins dilate and form varicosities. Segments of great saphenous veins are often suitable as coronary conduits. No studies have assessed the suitability of saphenous veins as coronary artery conduits in patients with varicose vein disease.
METHODS: Intraoperative high-resolution ultrasound studies were performed in coronary artery bypass graft procedures to assess lower extremity venous morphology in limbs of 77 patients without known venous disease, in 19 limbs with venous telangiectases, and in 23 limbs with varicose veins.
RESULTS: Dilated great saphenous vein segments were identified in 6% of normal limb venous segments compared with 21% of segments in limbs with telangiectases (p = 0.027) and 22% of segments in limbs with varicosities (p = 0.012). The incidence of absent or hypoplastic great saphenous vein segments is increased in limbs with varicosities (35%) compared with normal limbs (21%; p = 0.032). In the calf, at least one great saphenous vein segment suitable for coronary artery bypass grafting is present in 70% of limbs with varicosities and in 89% of limbs with telangiectases.
CONCLUSIONS: Ultrasound studies document that varicose veins are limited to accessory saphenous veins. Great saphenous vein conduits, identified by ultrasonography, are available in limbs with varicose vein disease.
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Introduction
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It has been presumed that saphenous veins in limbs with varicose veins cannot routinely be used as coronary artery conduits. This assertion is based on the view that venous dilatation and tortuosity affect all superficial veins in limbs with varicose vein disease. Alternative conduit sites and options for use in patients with venous varicosities have been reported [1, 2]. MacFarlane and colleagues [3] documented that great saphenous vein (GSV) segments below the knee do not become varicose even in patients with extensive below-knee varicosities. Fligelstone and coworkers [4] and Hammarsten and associates [5] performed ultrasound studies and venography in limbs with varicosities after high saphenous vein ligation and multiple stab phlebectomy. They reported that GSV length and lumen dimensions were suitable for vascular conduit in more than 60% of limbs. Mellière [6] performed preoperative ultrasound assessment in patients with varicose vein disease and demonstrated that more than 80% of limbs had normal or slightly dilated GSV segments.
Ultrasound studies in limbs with venous telangiectases demonstrate reflux into reticular veins, and this is often associated with incompetence of larger epifascial veins. In some cases, there is reflux into the deep venous system [7, 8]. Thibault and associates [9] performed ultrasound imaging in patients with symptomatic telangiectases and demonstrated that 23% have major sources of venous reflux within the GSV. No studies have systematically assessed the suitability of saphenous veins as coronary artery conduits in patients with venous telangiectases or varicose veins.
Correlation of anatomic and ultrasound studies demonstrates two types of longitudinal veins in the lower extremities [10–13]. The GSV lies deep to the saphenous fascia and above the muscular fascia. Accessory saphenous veins (ASVs) are superficial to the saphenous facial layer. The muscular and saphenous fasciae join after arching over the GSV, delimiting the saphenous compartment. This compartment contains the GSV, facial septa, adipose tissue, saphenous artery, and saphenous nerve [11–17]. All longitudinal veins devoid of a fascial envelope are ASVs. Accessory saphenous veins may dilate and develop into varicose veins. In varicose vein disease, dilatation and reflux may occur within GSVs, but development of varicosities does not occur owing to the firm investing saphenous and muscular fascia [15, 18].
Accessory saphenous veins may be anterior, posterior, or lateral to the GSV. Segments of ASVs and GSVs may be absent, atretic, or hypoplastic. The transition of an ASV as a branch of the GSV may be seamless, indistinct even during anatomic dissection. Each of the two veins has differing anatomic, histologic, and physiologic characteristics [11, 16]. On the basis of these findings and additional studies, it has been postulated that ASVs are prone to varicose changes [12, 14, 18].
The purpose of this study is to assess GSVs in limbs with telangiectases and varicosities and to document the suitability of GSVs as coronary artery conduits in limbs with venous varicosities. Great saphenous vein site selection criteria and issues related to venous varicosities in patients undergoing coronary artery bypass graft surgery are examined.
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Material and Methods
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This study was reviewed by the Sutter Health Central Area Institutional Review Committee and received exempt status approval. The study involves record review of intraoperative ultrasound reports and data on patients from September 22, 2004, through October 26, 2005.
This study was performed to define the incidence of GSVs suitable for use as coronary artery conduits in limbs with venous telangiectases and varicose veins. Consecutive, intraoperative ultrasound studies were performed in 154 limbs without venous disease (77 patients), in 19 limbs (12 patients) with telangiectases, and in 23 limbs (14 patients) with varicosities. Studies were performed in patients undergoing elective and emergent coronary artery bypass graft surgery. For the purpose of this study, venous telangiectases represent intradermal telangiectases present in a fan-shaped or cluster pattern, located in the thighs or calves, behind the knees, or over the ankles. The individual veins are less than 2 mm in diameter. Varicose veins are recognized as irregular dilated veins in a subcutaneous location anywhere in the lower extremity.
Intraoperative venous duplex ultrasound studies are performed routinely in all coronary artery bypass graft patients using a high-resolution duplex scanner and model 15L8 linear array probe (Acuson Sequoia 512 Ultrasound System, Acuson Corp, Mountain View, CA). After endotracheal intubation, a high thigh tourniquet is placed around the proximal thigh using a 1-inch rubber drain secured tightly with a clamp. This provides compression of the saphenous vein distal to the saphenofemoral junction. Venous distention approximates the distention achieved during vein conduit preparation. Real-time transverse axial scanning provides sufficient imaging to assess venous anatomy. Scans are performed from the ankle to the proximal thigh, with the leg externally rotated and the knee flexed. Initial ultrasound depth adjustment is 20 mm with 13.0 MHz probe scan frequency. Frequent tissue pressure with the scan head is used to compress the saphenous vein to identify areas of venous thrombosis. Venous abnormalities and internal lumen diameters of the distended vein segments are recorded. Scan time for each leg is usually 3 to 4 minutes. Additional scan time is necessary if the GSV is unsatisfactory and ASV segments require identification as conduit options. Ultrasound studies are performed during intraoperative preparatory procedures, avoiding unnecessary operative delays. Details and methodology of the procedure have been previously reported [19].
Patient data include age, sex, type of surgery, and ankle to brachial artery pressure index. Accessory saphenous veins and GSVs are evaluated in the proximal and distal calf and thigh. For the purpose of this study, a vein segment is defined as representing the length of vein at each of these four sites. Characteristics of the four ASV and four GSV segments in each limb, two in the thigh and two in the calf, are recorded.
Accessory saphenous vein and GSV segments are described as normal if they measure 2 to 5 mm in internal lumen diameter and extend half of the length of the calf or thigh, a length suitable for at least one coronary artery conduit. A small segment is defined as a narrow ASV or GSV segment, less than 2 mm in diameter, or not extending half of the length of the calf or thigh. Narrowed segments may represent absent, atretic, or hypoplastic veins [10]. Vein segments less than 2 mm in diameter are not considered for conduit use. Dilated ASV and GSV segments are identified as veins greater than 5 mm internal lumen diameter and extending approximately half of the length of the calf or thigh. Thrombosed veins are defined as incompletely compressible vein segments. On a few occasions, more then one abnormality is present within a limb segment. A vein segment is assigned a single category based on the major portion of the vein segment fulfilling the defined criteria.
An example of an ultrasound recording of a GSV and an ASV is shown in Figure 1. An ultrasound image of varicosities associated with a GSV is shown in Figure 2.
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Fig 1. Intraoperative ultrasound recording of great saphenous vein (G) and accessory saphenous vein (A). Transaxial image of the mid thigh. The great saphenous vein is located beneath the saphenous fascia and measures 2.7 mm in internal lumen diameter. The accessory saphenous vein measures 2.6 mm in diameter. White arrowheads indicate saphenous fascia. Black arrowheads identify muscular fascia. Vertical axis, full scale, is 20 mm.
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Fig 2. Intraoperative ultrasound recording of varicose veins (V) and great saphenous vein (large white arrowhead). Transaxial image of the mid calf. Varicose veins are located above the saphenous fascia. The small white arrowheads identify the saphenous fascia and adjacent border of varicose veins. The great saphenous vein is located beneath the saphenous fascia and above the muscular fascia and measures 1.6 mm in internal lumen diameter. Vertical axis, full scale, is 30 mm.
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Statistical analysis of categorical data is performed by the Mann-Whitney rank sum test statistic. All probability value statistics are two-tailed. Percentage values are rounded to whole numbers. In some instances, percentage values do not add to 100% as a result of whole number rounding. Vein diameter measurements, identified in Figures 1 and 2, are obtained from scanned images.
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Results
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Patient demographics include coronary artery bypass graft procedures in 76 men and 26 women. Mean age for all patients is 67.6 years. Average saphenous vein conduits per patient are 2.2. Additional procedures include internal mammary artery anastomoses (n = 50), aortic valve replacement (n = 18), and mitral valve repair or replacement (n = 9). Venous telangiectases were identified in 19 (10%) limbs, and varicosities were present in 23 (12%) limbs. Vein harvesting was performed endoscopically with the Guidant Vasoview Uniport Plus kit (Guidant Corp, Santa Clara, CA) in 34 instances. Surgical excision was performed at 126 limb sites. In some patients, endoscopic vein harvesting and surgical excision were both performed. More than one conduit was usually obtained at each vein excision site.
Normal Limbs
Dilated vein segments, in limbs without known venous disease, were identified in 34 of 616 venous segments (6%). All dilated segments were located in the thigh. Absent or hypoplastic venous segments were documented in 21% of venous segments. The remaining 74% of venous segments were in the range 2 to 5 mm internal lumen diameter and would be suitable for use as coronary artery conduits. No thrombosed venous segments were identified. The number of dilated, small, and normal-caliber GSV segments and their percentage limb distributions are shown in Table 1.
On the basis of venous segments measuring 2 to 5 mm internal lumen diameter, at least one GSV segment suitable for use as a coronary artery conduit was present in every limb. At least two segments could be harvested in 91% of limbs. Three segments were available in 61% of limbs, and four venous segments could be obtained in 42% of limbs.
Venous Telangiectases
Dilated GSV segments in limbs with venous telangiectases were identified in 16 of 76 venous segments (21%). All dilated GSV segments were located in the thigh. Small GSV segments were recorded in 13 venous segments (17%). Venous segments suitable for use as coronary conduits were identified in 62% of limb segments. No thrombosed venous segments were identified. Distributions of dilated, small, and normal venous segment dimensions in limbs with telangiectases are recorded in Table 2.
In all limbs with venous telangiectases, at least one GSV segment was identified as suitable for use as a coronary artery conduit. In 84% of limbs, at least two GSV segments were available for conduit use. At least three GSV segments could be used in 37% of limbs, and four venous segments, the entire GSV, could be used for bypass grafting in 26% of limbs with telangiectases.
The distribution of the size of limb segments between normal limbs and limbs with telangiectases was compared using the Mann-Whitney rank sum test. There was a statistical difference in size distribution of limb segments in the proximal thigh (p = 0.007) and distal thigh (p = 0.036) but not in the two calf segments (both p > 0.6).
Varicose Veins
A similar pattern of increased dilated vein segments was found in limbs with varicose veins. Dilated GSV segments were detected in 20 of 92 venous segments (22%). Small venous segments were found in 35% of venous segments, and normal-caliber venous segments were documented in 40%. Thrombosed venous segments, all in the distal calf, were detected in 3% of venous segments. Frequency distributions of GSV segment categories are shown in Table 3.
Varicosities imaged by ultrasound were always located superficial to the saphenous fascia, within the subcutaneous adipose tissue. In the event a GSV was not able to be ultrasonically detected between the muscular and saphenous fascia, ASVs were readily detected in a subcutaneous location. Normal diameter and dilated GSVs were easily identified. No GSV segment was documented to be tortuous.
At least one GSV segment, measuring between 2 and 5 mm internal lumen diameter, could be harvested in 78% of limbs with varicosities. Two GSV segments were suitable as conduits in 57% of limbs. The availability of GSV segments within a limb for use as coronary conduits in normal limbs and in limbs with telangiectases and varicose veins is illustrated in Figure 3.
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Fig 3. Percent great saphenous vein (GSV) segment distribution for normal-caliber vein segments, internal lumen diameter greater than 2 mm and less than 5 mm, in normal limbs, limbs with venous telangiectases, and limbs with varicose veins. Four great saphenous vein segments are identified in each limb. The abscissa notations >=1, >=2, and >=3 indicate that at least one, two, and three normal-size great saphenous vein segments are identified by ultrasound in the limb. The abscissa notation "4" indicates that four great saphenous vein segments are identified. There is a decreased incidence of suitable great saphenous vein segments for conduit use in limbs with varicose veins compared with normal limbs (p < 0.001). The distribution difference between normal limbs and limbs with telangiectases is of borderline significance (p = 0.054).
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Data analysis illustrates a predominance of normal-sized GSV segments within the thigh and calf in normal limbs and in the calf in limbs with venous telangiectases. Venous dilatation within the thigh in limbs with telangiectases and varicosities results in a reduction in suitable GSV segments for conduit use. In varicose vein disease, calf GSV segments have the highest likelihood for providing at least one suitable GSV segment for use as a coronary conduit. In 5 of 23 limbs with varicosities (22%), a satisfactory GSV segment for conduit use could not be identified in the entire limb.
Great saphenous vein size distribution was compared at the various vessel segment levels in normal limbs and in limbs with varicose veins using the Mann-Whitney rank sum test. There were statistically significant differences in GSV segment size distribution in the proximal thigh (p = 0.002), distal thigh (p = 0.006), and proximal calf (p < 0.001). Differences in distribution categories in the distal calf were of borderline significance (p = 0.052).
Although demographic findings were similar in normal limbs and in limbs with telangiectases and varicosities, the high frequency of dilated combined with absent or hypoplastic GSV segments in the thigh resulted in a reduction in the use of endoscopic vein harvesting in these patients. In patients with normal limbs, endoscopic vein harvesting was performed in 43% of cases. Endoscopic vein harvesting was performed in one limb with telangiectases and in no limbs with varicose veins.
Accessory Saphenous Veins
Accessory saphenous veins and collateral veins are readily distinguished from GSVs by their location above the saphenous fascia. Longitudinal ASV segments, in the range greater than 2 mm and less than 5 mm internal lumen diameter and extending half of the calf or thigh, were observed in 144 of 616 normal limb venous segments (23%). In limbs with venous telangiectases, ASV segments in this diameter and length range were present in 30% of limb segments. In limbs with varicosities, ASV segments were documented in 28% of the limb segments. A few dilated segments and a single thrombosed ASV segment in a limb with varicosities were observed. There were no statistical differences in distribution of small, normal-caliber, dilated, and thrombosed vein segments in normal limbs compared with limbs with telangiectases and varicosities (all p > 0.32). Varicosities were always observed above the saphenous fascia. Great saphenous vein segments adjacent to either varicosities or ASVs may be of normal caliber (Fig 1), absent, hypoplastic (Fig 2), dilated, or thrombosed.
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Comment
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Normal-appearing limbs, without evidence of venous disease, have a low incidence of dilated GSV segments (6%), all present in the thigh. The incidence of normal-sized GSV segments in the thigh is 75% and in the calf is 72%. The remaining GSV segments are small, measuring less than 2 mm in diameter. These small GSV segments cannot be used for saphenous conduits. Similar results have been reported by others [14, 20–24].
Limbs with telangiectases and varicosities have a high incidence of dilated and small GSV segments, compared with normal limbs. The finding of GSV dilatation in limbs with telangiectases supports the concept that reflux occurs in venous tributaries draining into the GSV, resulting in proximal dilatation of GSV segments in the thigh [9]. Findings in our study indicate that two suitable GSV segments could be harvested in 84% of limbs with telangiectases. In limbs with varicosities, the possibility of harvesting two normal-sized segments is reduced to 57%. In limbs with telangiectases or varicosities, thigh segments have a higher incidence of small and dilated GSV segments compared with calf segments. Similar findings have been reported by MacFarlane and coworkers [3]. Ultrasound studies can identify GSV lumen and length characteristics to optimize surgical site selection [19].
Both dilated and small venous segments contribute to a reduction in available sites for harvesting saphenous vein conduits. The finding of an increased incidence of small GSV segments in limbs with varicose veins is consistent with the investigations of Caggiati and Ricci [14] and Caggiati and Mendoza [15], who described an increased incidence of dilated ASV segments in limbs with proximal GSV atresia. They postulated that atretic GSV segments were causative in the development of varicose veins by diverting blood flow through adjacent ASVs, which then became dilated and varicose.
Accessory saphenous veins have characteristic features on ultrasound examination [12, 13]. In the diameter range 2 mm to 5 mm, they are common in normal limbs, occurring in 23% of venous segments. A slightly higher frequency is recorded in limbs with telangiectases and varicose veins. Because of their thin wall structure, ASVs may not be suitable for use as coronary artery conduits. Definitive studies are needed to resolve this issue. Ultrasonic identification of ASVs is important to consider in saphenous site selection to select optimal saphenous conduits for coronary artery bypass graft.
In this study, varicosities within GSV segments were not identified on ultrasound studies. Surgical excision of GSV segments, in limbs with varicose veins, also did not identify varicose GSV segments. In some of these GSV segments, venous valves were incompetent but vein diameter was of normal caliber, and these segments were suitable for use as coronary conduits.
Intraoperative ultrasound provides a rapid and effective means to assess GSV segments suitable for use as coronary artery conduits. Ultrasound guidance, particularly in limbs with telangiectases and varicosities, allows identification of suitable saphenous vein conduits, optimizing surgical site selection. The use of ASV segments for bypass conduits may not be comparable with GSV conduits because of their differing histologic and physiologic characteristics. Long-term assessment, comparing the use of ASVs and GSVs as coronary artery conduits, requires further investigation.
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References
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- Moritz A, Grabenwöger F, Wolner E. Mesh tube-calibrated varicose veins for coronary artery bypass grafting Ann Thorac Surg 1994;57:240-242.[Abstract]
- Canver CC. Conduit options in coronary artery bypass surgery Chest 1995;108:1150-1155.[Abstract/Free Full Text]
- MacFarlane R, Godwin RJ, Barabas AP. Are varicose veins and coronary artery bypass surgery compatible? Lancet 1985;2:859.[Medline]
- Fligelstone L, Carolan G, Pugh N, Shandall A, Lane I. An assessment of the long saphenous vein for potential use as a vascular conduit after varicose vein surgery J Vasc Surg 1993;18:836-840.[Medline]
- Hammarsten J, Pedersen P, Cederlund C-G, Campanello M. Long saphenous vein saving surgery for varicose veins Eur J Vasc Surg 1990;4:361-364.[Medline]
- Mellière D. Why and when to preserve the saphenous veins of varicose patients to serve as an arterial conduit J Mal Vasc 1994;19:216-221.[Medline]
- Weiss RA, Weiss MA. Doppler ultrasound findings in reticular veins of the thigh subdermic lateral venous system and implication for sclerotherapy J Dermatol Surg Oncol 1993;19:947-951.[Medline]
- Somjen GM, Ziegenbein R, Johnston AH, Royle JP. Anatomical examination of leg telangiectases with duplex scanning J Dermatol Surg Oncol 1993;19:940-945.[Medline]
- Thibault P, Bray A, Wlodarczyk J, Lewis W. Cosmetic leg veinsevaluation using duplex venous imaging. J Dermatol Surg Oncol 1990;16:612-618.[Medline]
- Caggiati A, Bergan JJ, Gloviczki P, Eklof B, Allegra C, Partsch H. Nomenclature of the veins of the lower limbextensions, refinements, and clinical application. J Vasc Surg 2005;41:719-724.[Medline]
- Papadopoulos NJ, Sherif MF, Albert EN. A fascial canal for the great saphenous veingross and microanatomical observations. J Anat 1981;132:321-329.[Medline]
- Caggiati A. The saphenous venous compartments Surg Radiol Anat 1999;21:29-34.[Medline]
- Lova RM, Cappelli M, Macchi C, et al. Macroscopic anatomy of the superficial veins of the lower limba systematic review based upon echography. It J Anat Embryol 2001;106:215-220.[Medline]
- Caggiati A, Ricci S. The caliber of the human long saphenous vein and its congenital variations Ann Anat 2000;182:195-201.[Medline]
- Caggiati A, Mendoza E. Segmental hypoplasia of the great saphenous vein and varicose disease Eur J Vasc Endovasc Surg 2004;28:257-261.[Medline]
- Caggiati A. Facial relationships of the long saphenous vein Circulation 1999;100:2547-2549.[Free Full Text]
- Lescalié F, Germouty I, Chevalier JM, Enon B, Moreau P, Pillet J. Extrinsic arterial supply of the great saphenous veinan anatomic study. Ann Vasc Surg 1986;1:273-277.[Medline]
- Caggiati A. Fascial relationships and structure of the tributaries of the saphenous veins Surg Radiol Anat 2000;22:191-196.[Medline]
- Cohn JD, Korver KF. Optimizing saphenous vein site selection using intraoperative venous duplex ultrasound scanning Ann Thorac Surg 2005;79:2013-2017.[Abstract/Free Full Text]
- Bagi P, Schroeder T, Sillesen H, Lorentzen JE. Real time B-mode mapping of the greater saphenous vein Eur J Vasc Surg 1989;3:103-105.[Medline]
- Head HD, Brown MF. Preoperative vein mapping for coronary artery bypass operations Ann Thorac Surg 1995;59:144-148.[Abstract/Free Full Text]
- Kupinski AM, Evans SM, Khan AM, et al. Ultrasonic characterization of the saphenous vein Cardiovasc Surg 1993;1:513-517.[Medline]
- Ruoff BA, Cranley JJ, Hannan LA, et al. Real-time duplex ultrasound mapping of the greater saphenous vein before in situ infrainguinal revascularization J Vasc Surg 1987;6:107-113.[Medline]
- Van Dijk LC, Wittens CH, Pieterman H, van Urk H. The value of pre-operative ultrasound mapping of the greater saphenous vein prior to ‘closed' in situ bypass operations Eur J Radiol 1996;23:235-237.[Medline]
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Abstract
Introduction
