- Email: [email protected]
Optimizing Saphenous Vein Site Selection Using Intraoperative Venous Duplex Ultrasound Scanning
Joseph D. Cohn, MD, FACS, and Keith F. Korver, MD, FACS Department of Surgery, Sutter Medical Center of Santa Rosa, Santa Rosa, California
Background. Saphenous vein is the most common conduit utilized for coronary artery bypass. However, preoperative noninvasive venous studies to evaluate saphenous vein morphology are not commonly performed due to limited logistical support. A prospective, nonrandomized study was developed to assess the utility of intraoperative saphenous vein duplex ultrasound studies in optimizing saphenous vein site selection. Methods. Intraoperative saphenous vein duplex scanning was performed in 58 consecutive patients undergoing coronary artery bypass surgery utilizing two-dimensional ultrasound monitoring equipment. Following anesthetic intubation, studies were performed by one of the surgeons. Most scans were completed in less than 8 minutes. Results. Findings demonstrate at least 1 venous abnormality in 31 of 116 (26.7%) above knee saphenous veins and 59 of 116 (50.9%) below knee veins. In 38 of 58 patients (65.5%), duplex ultrasound scanning proved
beneficial in surgical site selection. Most abnormalities are related to major branches and bifurcations except in the lower calf where small lumen caliber is the most common abnormal finding. Additional beneficial findings include identifying abnormal vein course, identifying suitable conduit in reoperative procedures and precise localization of vein segments for endoscopic surgery. Conclusions. Intraoperative saphenous vein duplex scanning is rapidly and easily accomplished with available operating room resources. Study information allows optimal surgical site selection, avoiding unnecessary surgical dissection, time delays, vein wastage and potential for wound complications. Optimizing incision site selection eliminates blind exploration for vein conduit, improves conduit planning, and expedites surgical dissection during endoscopic vein harvest.
S
Logistical support and scheduling coordination is often difficult because vein mapping requires skin marking and must be performed within a few days before surgery. In urgent or emergent circumstances, where knowledge of saphenous vein morphology would be most useful, vein mapping is not likely to be performed. Ultrasound studies have demonstrated saphenous vein abnormalities in more then 30% of limbs [8]. Ideally, identification of distended saphenous vein segments utilizing ultrasound scanning should be performed in all patients. Knowledge of small caliber vein segments, abnormal vein course, bifurcated vein segments, multiple vein branches, and thrombosed or dilated vein segments could then be used to plan incision sites for saphenous vein access and avoid needless, fruitless, and time consuming surgical dissection.
aphenous vein is the most common coronary artery bypass (CAB) conduit. Although clinical examination of the distal calf may suggest a satisfactory origin of the great saphenous vein, morphologic assessment of proximal segments remains unknown until surgical exploration. Benefits of preoperative saphenous vein mapping have been documented for peripheral vascular reconstructive procedures [1–3] and for assessment of coronary artery conduits [4, 5]. Complications of saphenous vein harvest include leg wound infections [6] and ischemic ulcers [7], and pose an increased risk in elderly patients with associated peripheral vascular compromise. Postoperative surgical site infection in a limb that does not provide a satisfactory venous conduit is frustrating, may lead to increased limb complications, and is a potentially preventable event [3, 5]. Use of vein mapping provides a means to accurately identify venous abnormalities. With precise knowledge of vein anatomy, direct incision over the vein segment may be performed, which eliminates extensive dissection and avoids development of skin flaps and hematoma. However, the standard noninvasive venous ultrasound procedure is time consuming and requires access to a noninvasive vascular laboratory with vascular technologist support personnel. Accepted for publication Dec 20, 2004. Address reprint requests to Dr Cohn, 5773 Shiloh Ridge, Santa Rosa, CA 95403; e-mail: [email protected].
© 2005 by The Society of Thoracic Surgeons Published by Elsevier Inc
(Ann Thorac Surg 2005;79:2013–7) © 2005 by The Society of Thoracic Surgeons
Material and Methods This prospective, nonrandomized, preliminary study was performed to define the utility of intraoperative duplex venous ultrasound studies to optimize saphenous vein harvesting during CAB surgery. The study consists of 58 consecutive patients undergoing CAB surgery and associated procedures. Studies were performed in elective and emergent cases. Intraoperative ultrasound venous studies are performed following endotracheal intubation and bladder catheterization with a high-resolution real0003-4975/05/$30.00 doi:10.1016/j.athoracsur.2004.12.022
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Optimizing Saphenous Vein Site Selection Using Intraoperative Venous Duplex Ultrasound Scanning
2014
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time duplex scanner (Acuson Sequoia 512 Ultrasound System; Acuson Corp, Mountain View, CA) and model 15L8 linear array probe. This probe is also utilized to assist in locating jugular veins and radial arteries, if difficulty is encountered during upper extremity vascular access. It is occasionally used to assess ascending aorta plaque and calcification prior to aortic arch cannulation. The same ultrasound equipment provides for routine intraoperative two-dimensional echocardiographic monitoring, with a TEV5Ms (Acuson Corp, Mountain View, CA) multiplane transesophageal probe. Following endotracheal intubation, a tourniquet is placed around the proximal thigh using a 1-inch Penrose drain secured tightly with a Kelly clamp to occlude the saphenous vein distal to the saphenofemoral junction. The low profile tourniquet allows scanning to be performed to the proximal thigh. Venous distension approximates the distension achieved during vein conduit preparation. All studies are performed by one of the operating surgeons. Real-time transverse axial scanning provides sufficient imaging to assess venous anatomy. Scans are performed with ultrasound transmission gel (Aquasonic 100; Parker Laboratories, Inc, Fairfield, NJ), from the ankle to the proximal thigh, with the leg externally rotated and the knee flexed. Initial ultrasound depth adjustment is 30 mm with 10.0-MHz probe scan frequency. Increased depth setting is necessary in large or obese limbs. Additional probe frequencies of 8.0, 11.5, and 13.0 MHz are also available. The rectilinear scan image facilitates morphologic interpretation and estimates of internal lumen dimensions. Vein tracking is rapidly performed along the course of the saphenous vein. Veins in obese limbs are readily identified. Skin marking is performed with indelible ink [9] (Pilot Super Color Marker B; Pilot Corp of America, Trumbull, CT). Location of the vein at the medial knee is identified and marked for dissection during endoscopic vein harvest. Frequent tissue pressure with the scan head is used to compress the saphenous vein in order to identify areas of
Ann Thorac Surg 2005;79:2013–7
venous thrombosis. Venous abnormalities and internal lumen diameters of the distended vein segments are recorded. Vein depth is noted in large or obese limbs. Scan time for each leg is usually 3 to 4 minutes. Normal studies are completed in less time. Additional scan time is necessary if the great saphenous vein is unsatisfactory and accessory saphenous vein segments require identification as conduit options. Patient data includes age, gender, type of surgery, ankle/brachial artery pressure index, presence of lower extremity varicosities, and history of stripping or ligation of lower extremity varicose veins. Saphenous vein segments were evaluated in the proximal and distal calf and thigh, reflecting the use of each of these vein segments at these sites as coronary conduits. Vein segments were considered normal if they were continuous and measured 2-mm to 5-mm internal diameter, with progressive increase in size proximally. A vein segment less than 2-mm internal diameter was considered small and unlikely to be considered for conduit use. A discontinuous segment was identified if there was a major branch or abnormality affecting lumen size of the great saphenous vein or if a major bifurcation was evident. Dilated vein segments were identified as veins greater than 5-mm internal diameter or with major focal dilatations. All vessels demonstrated normal compression on probe pressure. No thrombosed vein segments were detected. On occasion, more then one abnormality was present within a vein segment. Following each study, the benefit of the intraoperative ultrasound examination was recorded. An ultrasound study was considered a beneficial aid if the study directed vein harvesting away from abnormal vein segments. A benefit was also noted in endoscopic vein site selection in large or obese limbs where the vein was identified more than 35 mm from the skin surface and in a few additional isolated and unusual cases. Examples of characteristic imaging studies are shown in Figure 1. Statistical analysis of categorical data was
Fig 1. (A) Transaxial scan distal calf revealing 1.6-mm internal diameter great saphenous vein (arrowhead). (B) Scan image midcalf demonstrating great saphenous vein with major branch (two arrowheads). Largest vein measures 3.2-mm internal lumen diameter. (C) Scan image distal thigh illustrating great saphenous vein (arrowhead). Internal lumen diameter measures 3 mm. Vertical axes, all panels, 20-mm full scale.
COHN AND KORVER INTRAOPERATIVE DUPLEX SCANNING
Table 1. Abnormal Vein Segment Distribution Site Thigh Proximal Thigh Proximal Thigh Proximal Thigh Proximal Thigh Distal Thigh Distal Thigh Distal Thigh Distal Calf Proximal Calf Proximal Calf Proximal Calf Proximal Calf Distal Calf Distal Calf Distal Calf Distal
Diameter
Number
Normal Discontinous Dilated Small Normal Discontinous Dilated Small Normal Discontinous Dilated Small Normal Discontinous Dilated Small
94 19 2 4 89 24 2 5 61 44 0 34 80 22 0 27
Values record venous abnormalities in proximal and distal thigh and calf vein segments for the 116 limbs examined. A total of 464 venous segments were studied. More than one abnormality may be present in a segment. Normal ⫽ continuous segment between 2 mm and 5 mm internal lumen diameter, venectomy sites are recorded as zero; Discontinuous ⫽ significant bifurcation, branching or absent vein segment; Dilated ⫽ segment greater than 5-mm internal lumen diameter; Small ⫽ segment less than 2-mm internal lumen diameter.
performed by the Chi-square method.
Results Patient demographics include coronary bypass procedures in 38 males and 20 procedures in females. Mean age for all patients was 69.8 years old. Average saphenous vein conduits per patient were 2.5. Additional procedures included internal mammary artery anastomoses (25), aortic valve replacement (6), and mitral valve repair or replacement (8). Vein harvesting was performed endoscopically with the Guidant Vasoview Uniport Plus kit (Guidant Corp, Santa Clara, CA) in 43 instances and 54 times by surgical excision. Silberg Tissue Preparation System was utilized during endoscopic vein harvest (Mettler Electronics Corp, Anaheim, CA) to facilitate endoscopic dissection. Tabulation of vein morphology is recorded in Table 1. An abnormal event was recorded if the ultrasound scan demonstrated the abnormality to include a sufficient portion of the proximal or distal calf or thigh vein segment to preclude its use as a vein conduit. Eight
2015
venous segments were evaluated in each patient. A total of 464 venous segments were examined in the 58 patients studied. A total of 183 abnormalities were identified. Discontinuous segments were most common (59.6%) followed by small vessel segments (38.3%) and dilated vessels (2.2%). Abnormal venous morphology is most common in the proximal calf where 42.6% of all abnormalities were detected. The next most common site is the lower calf. Proximal thigh segments accounted for 13.7% of abnormalities and distal thigh segments contributed to 16.9% of all abnormalities. Of the 116 complete limbs examined, 45 (38.8%) were normal. Venous abnormalities in the right and left limbs demonstrated no limb preference. There was a statistical gender difference related to vein size with small lumen size predominating in females in the upper calf (p ⫽ 0.002). Discontinuities were also more prevalent in the upper calf in females (p ⫽ 0.02). There were no statistically significant site gender differences in frequency occurrence of other abnormalities. Utilization of intraoperative lower extremity venous ultrasound proved beneficial in 38 of 58 patients (65.5%), by identifying major areas of discontinuity, attenuated vein segments, depth and location of veins in obese limbs, and abnormal vein locations. Selective incisions were placed to avoid needless dissection and reduce vein harvest time delays. On occasions, small calf veins (2-mm internal diameter) were harvested. During vein preparation these veins distended sufficiently to be usable as a coronary conduit where a small diameter conduit to coronary artery match was suitable. In most cases, smallsized veins were not acceptable. As limb dissection of small vein segments was usually avoided, the decision process for utilizing small caliber saphenous vein segments as coronary artery conduits remains uncertain [5]. While not systematically investigated, use of intraoperative duplex scanning has proven useful in patients undergoing reoperative CAB surgery. Venous ultrasound studies in 1 patient demonstrated an overlooked great saphenous vein segment or an enlarged bifurcated vein segment, adjacent to an incision site that was suitable for use as a venous conduit. The incidence of fruitless attempts at vein harvesting may be estimated from analysis of the data in Table 2. If the right lower extremity is routinely utilized for saphenous vein harvesting then at least one significant venous abnormality would be encountered in 17 of 58 thigh segments (29.3%) and 26 of 58 calf segments (44.8%). This calculation possibly overestimates the incidence of unsuitable harvested vein segments because a portion of a
Table 2. Normal Limb Vein Sites Site Thigh Normal Calf Normal
Right n ⫽ 58
Left n ⫽ 58
Both n ⫽ 116
Percent Normal
41 32
44 25
85 57
73.3 49.1
Values record normal vein segments in both the proximal and distal thigh and proximal and distal calf. A normal occurrence for the thigh is recorded if the proximal and distal thigh segments in the same limb are both normal. A total of 116 limbs were examined.
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harvested vein containing some abnormality may be salvageable for conduit use.
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Comment Ruoff and colleagues [10] and others [1, 5, 8] have documented abnormalities in great saphenous vein segments. Kupinski and associates [8] described ultrasonic characteristics of saphenous veins in over 1400 limbs in patients undergoing peripheral vascular and coronary artery revascularization procedures. In their study, the thigh segment consisted of a single venous conduit in 67% of limbs. In the calf, a single vein was observed in 65% of limbs. Van Dijk and coworkers [11] found 20% of 44 patients to have great saphenous duplications and 23% to have narrow segments on preoperative ultrasound studies. Caggiati and Ricci [12] found segmental narrowing in 39.8% of saphenous veins in studies involving anatomic limb dissections and ultrasonography. These combined studies suggest an incidence of untrasonically detected venous abnormalities of the great saphenous vein in the range 20% to 40%. Patient position and techniques during ultrasound examinations have included 10-degree to 20-degree reversed Trendelenburg position without tourniquet [1, 4, 5]. Hoballah and colleagues [13] studied the effect of tourniquet application and position on saphenous venous distension in normal male volunteers. Maximum vein diameters were achieved with dependency and 40 mm Hg tourniquet inflation. Saphenous vein diameters, with tourniquet and reversed Trendelenburg position, increased 0.39 mm above the knee and 0.15 mm below the knee compared to dimensions recorded during supine position with tourniquet. The increase in vein caliber with increased venous pressure associated with reversed Trendelenburg position suggests that vein internal lumen dimension may be further increased following conduit preparation with directly applied fluid distension. Use of intraoperative ultrasound venous duplex scanning provides a safe and rapid means to assess saphenous vein morphology. Proximal thigh tourniquet application results in prompt distension of the saphenous vein and allows measurements of internal lumen dimensions. Ultrasound equipment utilized in this procedure is also utilized for intraoperative two-dimensional echocardiographic monitoring of myocardial function. A portable gray-scale ultrasound monitor or use of a sterile sheath over the scan probe would be other options to aid in intraoperative assessment of the saphenous vein. Data analysis demonstrates normal studies in 85 of 116 thigh veins (73.3%) and 57 of 116 calf veins (49.1%). Discontinuities represented the major abnormality in all segments except for the lower calf segment where small caliber veins were the most common abnormal finding. In 50 instances, more than one venous abnormality was present within a vein segment. Almost all of these were related to the association of discontinuities and small caliber veins. Isolated abnormal findings affecting site selection include a thigh segment vein dilatation, venous valve dilatation and a large posterior thigh vein arising from
Ann Thorac Surg 2005;79:2013–7
the short saphenous system with absence of the normally positioned great saphenous vein. Reoperations occurred in 3 patients. In one patient undergoing reoperative CAB, duplex scanning demonstrated a satisfactory vein segment adjacent to a previous surgical vein excision site. A similar finding was reported by Head and Brown [5]. In the two other patients, the remaining saphenous venous systems were normal. Findings in intraoperative ultrasound examinations provide a means to plan conduit options while limiting surgical incisions and avoiding vein waste. Other reports have demonstrated correlation of preoperative vein mapping with operative findings [3, 5, 6], and suggested a reduction in wound complications and infections attributable to surgical site selection. Allen and Shaar [14] utilized a portable intraoperative two-dimensional ultrasound system to locate the saphenous vein prior to endoscopic vein harvest. They documented a decrease in time required for identification and dissection of the saphenous vein, especially in obese patients. Intraoperative duplex ultrasound scanning proved beneficial in surgical site selection in 38 of 58 patients (65.5%). In the majority of cases, branched vessels, bifurcations, and small caliber veins were avoided and the better-quality limb was selected. In isolated instances, surgery was averted on limbs with major venous anatomic abnormalities. In obese patients, vein position and depth information proved valuable in surgical site incision placement before endoscopic vein harvest. Routinely, intraoperative ultrasound scan led to optimum endoscopic incision site selection and to the optimum sites for excisional vein harvesting. The unexpected high incidence of benefit utilizing intraoperative ultrasound likely relates to the greater use of saphenous vein as the conduit of choice and limited use of internal mammary artery in an older age population.
Conclusions Intraoperative venous duplex ultrasound study of the great saphenous veins with use of tourniquet is quickly and easily performed during intraoperative preparatory procedures. The study provides information related to venous abnormalities and distended vein lumen caliber. Intraoperative ultrasound scanning eliminates failed attempts at endoscopic or excisional vein harvesting in a calf or thigh with a small caliber vein, vein branches, dilatations or bifurcations. Precise incision site selection is identified for endoscopic vein harvesting. Optimal surgical vein excision site selection is achieved by avoiding incisions over abnormal vein segments.
The authors thank James C. Finn, MD, cardiac anesthesiologist, for suggesting use of the small body part ultrasound probe and monitoring scanner for intraoperative venous duplex ultrasound scanning. We thank him for his assistance in integrating and coordinating postintubation preparatory procedures. The authors thank him and Peter Anastassiou, MD, for manuscript review.
References 1. Bagi P, Schroeder T, Sillesen H, Lorentzen JE. Real time B-mode mapping of the greater saphenous vein. Eur J Vasc Surg 1989;3:103–5. 2. Buchbinder D, Semrow C, Friedell ML, Ryan T, Calligaro K, Rollins D. B-mode ultrasonic imaging in the preoperative evaluation of saphenous vein. Am Surg 1987;53:368 –72. 3. Seeger, JM, Schmidt JH, Flynn TC. Preoperative saphenous and cephalic vein mapping as an adjunct to reconstructive arterial surgery. Ann Surg 1987;205:733–9. 4. Lemmer JH, Meng RL, Corson JD, Miller E. Preoperative saphenous vein mapping for coronary artery bypass. J Card Surg 1988;3:237– 40. 5. Head HD, Brown MF. Preoperative vein mapping for coronary artery bypass operations. Ann Thor Surg 1995;59:144 – 8. 6. DeLaria GA, Hunter JA, Goldin MD, Serry C, Javid H, Najafi H. Leg wound complications associated with coronary revascularization. J Thorac Cardiovasc Surg 1981;81:403–7. 7. Gandhi RH, Katz D, Wheeler JR, et al. Vein harvest ischemia: a peripheral vascular complication of coronary artery bypass grafting. Cardiovasc Surg 1994;2:478 – 83.
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8. Kupinski AM, Evans SM, Khan AM, et al. Ultrasonic characterization of the saphenous vein. Cardiovasc Surg 1993;1:513–7. 9. Magee TR, Leopold PW, Campbell WB. Vein marking through ultrasound coupling gel. Eur J Vasc Surg 1990;4:491–2. 10. 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: 107–13. 11. 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;23:235–7. 12. Caggiati A, Ricci S. The caliber of the human long saphenous vein and its congenital variations. Anat Anz 2000;182:195–201. 13. Hoballah JJ, Corry DC, Rossley N, Chalmers RTA, Sharp WJ. Duplex saphenous vein mapping: venous occlusion and dependent position facilitate imaging. Vasc Endovasc Surg 2002;36:377– 80. 14. Allen KB, Shaar CJ. Facile location of the saphenous vein during endoscopic vessel harvesting. Ann Thor Surg 2000;69:295–7.
Southern Thoracic Surgical Association: Fifty-Second Annual Meeting The Fifty-Second Annual Meeting of the Southern Thoracic Surgical Association (STSA) will be held November 10 –12, 2005, in Orlando, Florida. The Postgraduate Course will be held the morning of Thursday, November 10, 2005, and will provide in-depth coverage of cardiothoracic surgical topics selected primarily as a means to enhance and broaden the knowledge of practicing thoracic and cardiac surgeons. Manuscripts accepted for the Resident Competition
must be submitted to the STSA headquarters office no later than September 16, 2005. The Resident Award will be based on abstract, presentation, and manuscript. Applications for membership should be completed by September 15, 2005, and forwarded to Richard L. Prager, MD, Membership Committee Chairman, Southern Thoracic Surgical Association, 633 N Saint Clair St, Suite 2320, Chicago, IL 60611-3658.
Please visit the STSA (http://www.stsa.org) or CTSNet (http://www.ctsnet.org) websites for detailed information on submitting abstracts. All abstracts must be submitted electronically for consideration.
© 2005 by The Society of Thoracic Surgeons Published by Elsevier Inc
Ann Thorac Surg 2005;79:2017
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0003-4975/05/$30.00
CARDIOVASCULAR
Ann Thorac Surg 2005;79:2013–7
Background. Saphenous vein is the most common conduit utilized for coronary artery bypass. However, preoperative noninvasive venous studies to evaluate saphenous vein morphology are not commonly performed due to limited logistical support. A prospective, nonrandomized study was developed to assess the utility of intraoperative saphenous vein duplex ultrasound studies in optimizing saphenous vein site selection. Methods. Intraoperative saphenous vein duplex scanning was performed in 58 consecutive patients undergoing coronary artery bypass surgery utilizing two-dimensional ultrasound monitoring equipment. Following anesthetic intubation, studies were performed by one of the surgeons. Most scans were completed in less than 8 minutes. Results. Findings demonstrate at least 1 venous abnormality in 31 of 116 (26.7%) above knee saphenous veins and 59 of 116 (50.9%) below knee veins. In 38 of 58 patients (65.5%), duplex ultrasound scanning proved
beneficial in surgical site selection. Most abnormalities are related to major branches and bifurcations except in the lower calf where small lumen caliber is the most common abnormal finding. Additional beneficial findings include identifying abnormal vein course, identifying suitable conduit in reoperative procedures and precise localization of vein segments for endoscopic surgery. Conclusions. Intraoperative saphenous vein duplex scanning is rapidly and easily accomplished with available operating room resources. Study information allows optimal surgical site selection, avoiding unnecessary surgical dissection, time delays, vein wastage and potential for wound complications. Optimizing incision site selection eliminates blind exploration for vein conduit, improves conduit planning, and expedites surgical dissection during endoscopic vein harvest.
S
Logistical support and scheduling coordination is often difficult because vein mapping requires skin marking and must be performed within a few days before surgery. In urgent or emergent circumstances, where knowledge of saphenous vein morphology would be most useful, vein mapping is not likely to be performed. Ultrasound studies have demonstrated saphenous vein abnormalities in more then 30% of limbs [8]. Ideally, identification of distended saphenous vein segments utilizing ultrasound scanning should be performed in all patients. Knowledge of small caliber vein segments, abnormal vein course, bifurcated vein segments, multiple vein branches, and thrombosed or dilated vein segments could then be used to plan incision sites for saphenous vein access and avoid needless, fruitless, and time consuming surgical dissection.
aphenous vein is the most common coronary artery bypass (CAB) conduit. Although clinical examination of the distal calf may suggest a satisfactory origin of the great saphenous vein, morphologic assessment of proximal segments remains unknown until surgical exploration. Benefits of preoperative saphenous vein mapping have been documented for peripheral vascular reconstructive procedures [1–3] and for assessment of coronary artery conduits [4, 5]. Complications of saphenous vein harvest include leg wound infections [6] and ischemic ulcers [7], and pose an increased risk in elderly patients with associated peripheral vascular compromise. Postoperative surgical site infection in a limb that does not provide a satisfactory venous conduit is frustrating, may lead to increased limb complications, and is a potentially preventable event [3, 5]. Use of vein mapping provides a means to accurately identify venous abnormalities. With precise knowledge of vein anatomy, direct incision over the vein segment may be performed, which eliminates extensive dissection and avoids development of skin flaps and hematoma. However, the standard noninvasive venous ultrasound procedure is time consuming and requires access to a noninvasive vascular laboratory with vascular technologist support personnel. Accepted for publication Dec 20, 2004. Address reprint requests to Dr Cohn, 5773 Shiloh Ridge, Santa Rosa, CA 95403; e-mail: [email protected].
© 2005 by The Society of Thoracic Surgeons Published by Elsevier Inc
(Ann Thorac Surg 2005;79:2013–7) © 2005 by The Society of Thoracic Surgeons
Material and Methods This prospective, nonrandomized, preliminary study was performed to define the utility of intraoperative duplex venous ultrasound studies to optimize saphenous vein harvesting during CAB surgery. The study consists of 58 consecutive patients undergoing CAB surgery and associated procedures. Studies were performed in elective and emergent cases. Intraoperative ultrasound venous studies are performed following endotracheal intubation and bladder catheterization with a high-resolution real0003-4975/05/$30.00 doi:10.1016/j.athoracsur.2004.12.022
CARDIOVASCULAR
Optimizing Saphenous Vein Site Selection Using Intraoperative Venous Duplex Ultrasound Scanning
2014
COHN AND KORVER INTRAOPERATIVE DUPLEX SCANNING
CARDIOVASCULAR
time duplex scanner (Acuson Sequoia 512 Ultrasound System; Acuson Corp, Mountain View, CA) and model 15L8 linear array probe. This probe is also utilized to assist in locating jugular veins and radial arteries, if difficulty is encountered during upper extremity vascular access. It is occasionally used to assess ascending aorta plaque and calcification prior to aortic arch cannulation. The same ultrasound equipment provides for routine intraoperative two-dimensional echocardiographic monitoring, with a TEV5Ms (Acuson Corp, Mountain View, CA) multiplane transesophageal probe. Following endotracheal intubation, a tourniquet is placed around the proximal thigh using a 1-inch Penrose drain secured tightly with a Kelly clamp to occlude the saphenous vein distal to the saphenofemoral junction. The low profile tourniquet allows scanning to be performed to the proximal thigh. Venous distension approximates the distension achieved during vein conduit preparation. All studies are performed by one of the operating surgeons. Real-time transverse axial scanning provides sufficient imaging to assess venous anatomy. Scans are performed with ultrasound transmission gel (Aquasonic 100; Parker Laboratories, Inc, Fairfield, NJ), from the ankle to the proximal thigh, with the leg externally rotated and the knee flexed. Initial ultrasound depth adjustment is 30 mm with 10.0-MHz probe scan frequency. Increased depth setting is necessary in large or obese limbs. Additional probe frequencies of 8.0, 11.5, and 13.0 MHz are also available. The rectilinear scan image facilitates morphologic interpretation and estimates of internal lumen dimensions. Vein tracking is rapidly performed along the course of the saphenous vein. Veins in obese limbs are readily identified. Skin marking is performed with indelible ink [9] (Pilot Super Color Marker B; Pilot Corp of America, Trumbull, CT). Location of the vein at the medial knee is identified and marked for dissection during endoscopic vein harvest. Frequent tissue pressure with the scan head is used to compress the saphenous vein in order to identify areas of
Ann Thorac Surg 2005;79:2013–7
venous thrombosis. Venous abnormalities and internal lumen diameters of the distended vein segments are recorded. Vein depth is noted in large or obese limbs. Scan time for each leg is usually 3 to 4 minutes. Normal studies are completed in less time. Additional scan time is necessary if the great saphenous vein is unsatisfactory and accessory saphenous vein segments require identification as conduit options. Patient data includes age, gender, type of surgery, ankle/brachial artery pressure index, presence of lower extremity varicosities, and history of stripping or ligation of lower extremity varicose veins. Saphenous vein segments were evaluated in the proximal and distal calf and thigh, reflecting the use of each of these vein segments at these sites as coronary conduits. Vein segments were considered normal if they were continuous and measured 2-mm to 5-mm internal diameter, with progressive increase in size proximally. A vein segment less than 2-mm internal diameter was considered small and unlikely to be considered for conduit use. A discontinuous segment was identified if there was a major branch or abnormality affecting lumen size of the great saphenous vein or if a major bifurcation was evident. Dilated vein segments were identified as veins greater than 5-mm internal diameter or with major focal dilatations. All vessels demonstrated normal compression on probe pressure. No thrombosed vein segments were detected. On occasion, more then one abnormality was present within a vein segment. Following each study, the benefit of the intraoperative ultrasound examination was recorded. An ultrasound study was considered a beneficial aid if the study directed vein harvesting away from abnormal vein segments. A benefit was also noted in endoscopic vein site selection in large or obese limbs where the vein was identified more than 35 mm from the skin surface and in a few additional isolated and unusual cases. Examples of characteristic imaging studies are shown in Figure 1. Statistical analysis of categorical data was
Fig 1. (A) Transaxial scan distal calf revealing 1.6-mm internal diameter great saphenous vein (arrowhead). (B) Scan image midcalf demonstrating great saphenous vein with major branch (two arrowheads). Largest vein measures 3.2-mm internal lumen diameter. (C) Scan image distal thigh illustrating great saphenous vein (arrowhead). Internal lumen diameter measures 3 mm. Vertical axes, all panels, 20-mm full scale.
COHN AND KORVER INTRAOPERATIVE DUPLEX SCANNING
Table 1. Abnormal Vein Segment Distribution Site Thigh Proximal Thigh Proximal Thigh Proximal Thigh Proximal Thigh Distal Thigh Distal Thigh Distal Thigh Distal Calf Proximal Calf Proximal Calf Proximal Calf Proximal Calf Distal Calf Distal Calf Distal Calf Distal
Diameter
Number
Normal Discontinous Dilated Small Normal Discontinous Dilated Small Normal Discontinous Dilated Small Normal Discontinous Dilated Small
94 19 2 4 89 24 2 5 61 44 0 34 80 22 0 27
Values record venous abnormalities in proximal and distal thigh and calf vein segments for the 116 limbs examined. A total of 464 venous segments were studied. More than one abnormality may be present in a segment. Normal ⫽ continuous segment between 2 mm and 5 mm internal lumen diameter, venectomy sites are recorded as zero; Discontinuous ⫽ significant bifurcation, branching or absent vein segment; Dilated ⫽ segment greater than 5-mm internal lumen diameter; Small ⫽ segment less than 2-mm internal lumen diameter.
performed by the Chi-square method.
Results Patient demographics include coronary bypass procedures in 38 males and 20 procedures in females. Mean age for all patients was 69.8 years old. Average saphenous vein conduits per patient were 2.5. Additional procedures included internal mammary artery anastomoses (25), aortic valve replacement (6), and mitral valve repair or replacement (8). Vein harvesting was performed endoscopically with the Guidant Vasoview Uniport Plus kit (Guidant Corp, Santa Clara, CA) in 43 instances and 54 times by surgical excision. Silberg Tissue Preparation System was utilized during endoscopic vein harvest (Mettler Electronics Corp, Anaheim, CA) to facilitate endoscopic dissection. Tabulation of vein morphology is recorded in Table 1. An abnormal event was recorded if the ultrasound scan demonstrated the abnormality to include a sufficient portion of the proximal or distal calf or thigh vein segment to preclude its use as a vein conduit. Eight
2015
venous segments were evaluated in each patient. A total of 464 venous segments were examined in the 58 patients studied. A total of 183 abnormalities were identified. Discontinuous segments were most common (59.6%) followed by small vessel segments (38.3%) and dilated vessels (2.2%). Abnormal venous morphology is most common in the proximal calf where 42.6% of all abnormalities were detected. The next most common site is the lower calf. Proximal thigh segments accounted for 13.7% of abnormalities and distal thigh segments contributed to 16.9% of all abnormalities. Of the 116 complete limbs examined, 45 (38.8%) were normal. Venous abnormalities in the right and left limbs demonstrated no limb preference. There was a statistical gender difference related to vein size with small lumen size predominating in females in the upper calf (p ⫽ 0.002). Discontinuities were also more prevalent in the upper calf in females (p ⫽ 0.02). There were no statistically significant site gender differences in frequency occurrence of other abnormalities. Utilization of intraoperative lower extremity venous ultrasound proved beneficial in 38 of 58 patients (65.5%), by identifying major areas of discontinuity, attenuated vein segments, depth and location of veins in obese limbs, and abnormal vein locations. Selective incisions were placed to avoid needless dissection and reduce vein harvest time delays. On occasions, small calf veins (2-mm internal diameter) were harvested. During vein preparation these veins distended sufficiently to be usable as a coronary conduit where a small diameter conduit to coronary artery match was suitable. In most cases, smallsized veins were not acceptable. As limb dissection of small vein segments was usually avoided, the decision process for utilizing small caliber saphenous vein segments as coronary artery conduits remains uncertain [5]. While not systematically investigated, use of intraoperative duplex scanning has proven useful in patients undergoing reoperative CAB surgery. Venous ultrasound studies in 1 patient demonstrated an overlooked great saphenous vein segment or an enlarged bifurcated vein segment, adjacent to an incision site that was suitable for use as a venous conduit. The incidence of fruitless attempts at vein harvesting may be estimated from analysis of the data in Table 2. If the right lower extremity is routinely utilized for saphenous vein harvesting then at least one significant venous abnormality would be encountered in 17 of 58 thigh segments (29.3%) and 26 of 58 calf segments (44.8%). This calculation possibly overestimates the incidence of unsuitable harvested vein segments because a portion of a
Table 2. Normal Limb Vein Sites Site Thigh Normal Calf Normal
Right n ⫽ 58
Left n ⫽ 58
Both n ⫽ 116
Percent Normal
41 32
44 25
85 57
73.3 49.1
Values record normal vein segments in both the proximal and distal thigh and proximal and distal calf. A normal occurrence for the thigh is recorded if the proximal and distal thigh segments in the same limb are both normal. A total of 116 limbs were examined.
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harvested vein containing some abnormality may be salvageable for conduit use.
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Comment Ruoff and colleagues [10] and others [1, 5, 8] have documented abnormalities in great saphenous vein segments. Kupinski and associates [8] described ultrasonic characteristics of saphenous veins in over 1400 limbs in patients undergoing peripheral vascular and coronary artery revascularization procedures. In their study, the thigh segment consisted of a single venous conduit in 67% of limbs. In the calf, a single vein was observed in 65% of limbs. Van Dijk and coworkers [11] found 20% of 44 patients to have great saphenous duplications and 23% to have narrow segments on preoperative ultrasound studies. Caggiati and Ricci [12] found segmental narrowing in 39.8% of saphenous veins in studies involving anatomic limb dissections and ultrasonography. These combined studies suggest an incidence of untrasonically detected venous abnormalities of the great saphenous vein in the range 20% to 40%. Patient position and techniques during ultrasound examinations have included 10-degree to 20-degree reversed Trendelenburg position without tourniquet [1, 4, 5]. Hoballah and colleagues [13] studied the effect of tourniquet application and position on saphenous venous distension in normal male volunteers. Maximum vein diameters were achieved with dependency and 40 mm Hg tourniquet inflation. Saphenous vein diameters, with tourniquet and reversed Trendelenburg position, increased 0.39 mm above the knee and 0.15 mm below the knee compared to dimensions recorded during supine position with tourniquet. The increase in vein caliber with increased venous pressure associated with reversed Trendelenburg position suggests that vein internal lumen dimension may be further increased following conduit preparation with directly applied fluid distension. Use of intraoperative ultrasound venous duplex scanning provides a safe and rapid means to assess saphenous vein morphology. Proximal thigh tourniquet application results in prompt distension of the saphenous vein and allows measurements of internal lumen dimensions. Ultrasound equipment utilized in this procedure is also utilized for intraoperative two-dimensional echocardiographic monitoring of myocardial function. A portable gray-scale ultrasound monitor or use of a sterile sheath over the scan probe would be other options to aid in intraoperative assessment of the saphenous vein. Data analysis demonstrates normal studies in 85 of 116 thigh veins (73.3%) and 57 of 116 calf veins (49.1%). Discontinuities represented the major abnormality in all segments except for the lower calf segment where small caliber veins were the most common abnormal finding. In 50 instances, more than one venous abnormality was present within a vein segment. Almost all of these were related to the association of discontinuities and small caliber veins. Isolated abnormal findings affecting site selection include a thigh segment vein dilatation, venous valve dilatation and a large posterior thigh vein arising from
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the short saphenous system with absence of the normally positioned great saphenous vein. Reoperations occurred in 3 patients. In one patient undergoing reoperative CAB, duplex scanning demonstrated a satisfactory vein segment adjacent to a previous surgical vein excision site. A similar finding was reported by Head and Brown [5]. In the two other patients, the remaining saphenous venous systems were normal. Findings in intraoperative ultrasound examinations provide a means to plan conduit options while limiting surgical incisions and avoiding vein waste. Other reports have demonstrated correlation of preoperative vein mapping with operative findings [3, 5, 6], and suggested a reduction in wound complications and infections attributable to surgical site selection. Allen and Shaar [14] utilized a portable intraoperative two-dimensional ultrasound system to locate the saphenous vein prior to endoscopic vein harvest. They documented a decrease in time required for identification and dissection of the saphenous vein, especially in obese patients. Intraoperative duplex ultrasound scanning proved beneficial in surgical site selection in 38 of 58 patients (65.5%). In the majority of cases, branched vessels, bifurcations, and small caliber veins were avoided and the better-quality limb was selected. In isolated instances, surgery was averted on limbs with major venous anatomic abnormalities. In obese patients, vein position and depth information proved valuable in surgical site incision placement before endoscopic vein harvest. Routinely, intraoperative ultrasound scan led to optimum endoscopic incision site selection and to the optimum sites for excisional vein harvesting. The unexpected high incidence of benefit utilizing intraoperative ultrasound likely relates to the greater use of saphenous vein as the conduit of choice and limited use of internal mammary artery in an older age population.
Conclusions Intraoperative venous duplex ultrasound study of the great saphenous veins with use of tourniquet is quickly and easily performed during intraoperative preparatory procedures. The study provides information related to venous abnormalities and distended vein lumen caliber. Intraoperative ultrasound scanning eliminates failed attempts at endoscopic or excisional vein harvesting in a calf or thigh with a small caliber vein, vein branches, dilatations or bifurcations. Precise incision site selection is identified for endoscopic vein harvesting. Optimal surgical vein excision site selection is achieved by avoiding incisions over abnormal vein segments.
The authors thank James C. Finn, MD, cardiac anesthesiologist, for suggesting use of the small body part ultrasound probe and monitoring scanner for intraoperative venous duplex ultrasound scanning. We thank him for his assistance in integrating and coordinating postintubation preparatory procedures. The authors thank him and Peter Anastassiou, MD, for manuscript review.
References 1. Bagi P, Schroeder T, Sillesen H, Lorentzen JE. Real time B-mode mapping of the greater saphenous vein. Eur J Vasc Surg 1989;3:103–5. 2. Buchbinder D, Semrow C, Friedell ML, Ryan T, Calligaro K, Rollins D. B-mode ultrasonic imaging in the preoperative evaluation of saphenous vein. Am Surg 1987;53:368 –72. 3. Seeger, JM, Schmidt JH, Flynn TC. Preoperative saphenous and cephalic vein mapping as an adjunct to reconstructive arterial surgery. Ann Surg 1987;205:733–9. 4. Lemmer JH, Meng RL, Corson JD, Miller E. Preoperative saphenous vein mapping for coronary artery bypass. J Card Surg 1988;3:237– 40. 5. Head HD, Brown MF. Preoperative vein mapping for coronary artery bypass operations. Ann Thor Surg 1995;59:144 – 8. 6. DeLaria GA, Hunter JA, Goldin MD, Serry C, Javid H, Najafi H. Leg wound complications associated with coronary revascularization. J Thorac Cardiovasc Surg 1981;81:403–7. 7. Gandhi RH, Katz D, Wheeler JR, et al. Vein harvest ischemia: a peripheral vascular complication of coronary artery bypass grafting. Cardiovasc Surg 1994;2:478 – 83.
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8. Kupinski AM, Evans SM, Khan AM, et al. Ultrasonic characterization of the saphenous vein. Cardiovasc Surg 1993;1:513–7. 9. Magee TR, Leopold PW, Campbell WB. Vein marking through ultrasound coupling gel. Eur J Vasc Surg 1990;4:491–2. 10. 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: 107–13. 11. 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;23:235–7. 12. Caggiati A, Ricci S. The caliber of the human long saphenous vein and its congenital variations. Anat Anz 2000;182:195–201. 13. Hoballah JJ, Corry DC, Rossley N, Chalmers RTA, Sharp WJ. Duplex saphenous vein mapping: venous occlusion and dependent position facilitate imaging. Vasc Endovasc Surg 2002;36:377– 80. 14. Allen KB, Shaar CJ. Facile location of the saphenous vein during endoscopic vessel harvesting. Ann Thor Surg 2000;69:295–7.
Southern Thoracic Surgical Association: Fifty-Second Annual Meeting The Fifty-Second Annual Meeting of the Southern Thoracic Surgical Association (STSA) will be held November 10 –12, 2005, in Orlando, Florida. The Postgraduate Course will be held the morning of Thursday, November 10, 2005, and will provide in-depth coverage of cardiothoracic surgical topics selected primarily as a means to enhance and broaden the knowledge of practicing thoracic and cardiac surgeons. Manuscripts accepted for the Resident Competition
must be submitted to the STSA headquarters office no later than September 16, 2005. The Resident Award will be based on abstract, presentation, and manuscript. Applications for membership should be completed by September 15, 2005, and forwarded to Richard L. Prager, MD, Membership Committee Chairman, Southern Thoracic Surgical Association, 633 N Saint Clair St, Suite 2320, Chicago, IL 60611-3658.
Please visit the STSA (http://www.stsa.org) or CTSNet (http://www.ctsnet.org) websites for detailed information on submitting abstracts. All abstracts must be submitted electronically for consideration.
© 2005 by The Society of Thoracic Surgeons Published by Elsevier Inc
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