Venous Conduits Research Articles

8 Does the addition of a radial artery graft improve survival after higher risk coronary surgery? A Propensity-Score analysis

Introduction The use of the radial artery as a second arterial graft during coronary surgery has become popular due to high patency, encouraging clinical outcomes and low harvest site complication rates. However it is not clear whether higher risk patients derive such benefits. We sought to assess this by examining outcomes in higher risk subgroups. Methods A multicentre database was analysed. From 2001 to 2009, 11 388 patients underwent isolated multivessel coronary surgery. We identified a higher risk subgroup (n=3149) according to emergent status, coronary instability, low ejection fraction, aortic counterpulsation or anticoagulant status. Among these, 2231 (71%) received at least 1 radial artery graft in addition to a left internal thoracic artery (LITA). The remaining 918 (29%) received LITA and veins only. Propensity-score matching and adjustment was performed to correct for group differences. Results Patients who did not receive a radial artery were more likely to be older (mean age, radial: 66±10 years vs vein: 71±10, p 0.99) and combined any mortality/morbidity (30% vs 32%, p=0.33). At 7 years, survival between radial and vein groups was similar (79±2.5% vs 80±2.5%, p=0.74). Propensity-adjusted multivariable regression did not show radial artery to be protective from 30-day mortality (p=0.14, OR 0.67, 0.40 to 1.13), 30-day MACCE (p=0.23, OR 0.76, 0.48 to 1.20), or mid-term mortality (p=0.79, HR 0.97, 0.78 to 1.20). Conclusions This multicentre analysis suggests that patients with the greatest coronary instability, urgency of surgery, or impairment of ventricular function are not disadvantaged in the early and mid-term by use of a single arterial graft. Limitations include the inability to correct for unquantifiable variables retrospectively. Despite this, surgeons may utilise clinical judgement to select radial or venous conduits to supplement the LITA according to other patient factors or technical preference without prejudicing outcome.

Mineralocorticoid receptor expression in human venous smooth muscle cells: a potential role for aldosterone signaling in vein graft arterialization.

Experimental studies have suggested a role for the local renin-angiotensin-aldosterone system in the response to vascular injury. Clinical data support that aldosterone, via activation of the mineralocorticoid receptor (MR), is an important mediator of vascular damage in humans with cardiovascular disease. In mineralocorticoid-sensitive target tissue, aldosterone specificity for MR is conferred enzymatically by the cortisol-inactivating enzyme 11β-hydroxysteroid-dehydrogenase-2 (11βHSD2). However, the role of MR/aldosterone signaling in the venous system has not been explored. We hypothesized that MR expression and signaling in venous smooth muscle cells contributes to the arterialization of venous conduits and the injury response in vein bypass grafts. MR immunostaining was observed in all samples of excised human peripheral vein graft lesions and in explanted experimental rabbit carotid interposition vein grafts, with minimal staining in control greater saphenous vein. We also found upregulated transcriptional expression of both MR and 11βHSD2 in human vein graft and rabbit vein graft, whereas control greater saphenous vein expressed minimal MR and no detectable 11βHSD2. The expression of MR and 11βHSD2 was confirmed in cultured human saphenous venous smooth muscle cells (hSVSMCs). Using an adenovirus containing a MR response element-driven reporter gene, we demonstrate that MR in hSVSMCs is capable of mediating aldosterone-induced gene activation. The functional significance for MR signaling in hSVSMCs is supported by the aldosterone-induced increase of angiotensin II type-1 receptor gene expression that was inhibited by the MR antagonist spironolactone. The upregulation of MR and 11βHSD2 suggests that aldosterone-mediated tissue injury plays a role in vein graft arterialization.

Ausscore Relates to Cost of Isolated CABG Surgery

sity adjusted multivariable Cox regression did not show radial artery to be protective from mid-term mortality (p= 0.79, HR 0.97, 0.78–1.20). Furthermore, 548 patients in the radial groupwerepropensity-matched to 548 receiving only veins.At 30days, therewere comparable rates ofmortality (radial: 2% vs. vein: 3%, p= 0.19), stroke (1% vs. 1%, p= 0.51), myocardial infarction (1% vs. 1%, p= 0.77), composite MACCE (2% vs. 4%, p= 0.12), return to theatre (5% vs. 7%, p= 0.19) and hospital readmissions (12% vs. 12%, p> 0.99). At seven years, survival between radial and vein groups were also similar (79± 2.5% vs. 80± 2.5%, p= 0.74). Discussion and conclusion: This substantial multicentre analysis suggests that patients with the greatest coronary instability, urgency of surgery, or impairment of ventricular function are not disadvantaged in short-term outcome or mid-term survival by use of only a single arterial graft. Limitations include the inability to correct for unquantifiable variables retrospectively. In spite of this, surgeons may utilise clinical judgement to select radial or venous conduits to supplement the LITA according to other patient factors or technical preference without prejudicing outcome. doi:10.1016/j.hlc.2010.11.030 Ausscore Relates to Cost of Isolated CABG Surgery Diem Dinh2,∗, Andrew E. Newcomb1, Molla Huq2, D

Primary arteriovenous fistula inflow proximalization for patients at high risk for dialysis access-associated ischemic steal syndrome

Establishing a functional vascular access while minimizing the risk of dialysis access-associated ischemic steal syndrome (DASS) may present a challenging problem in patients with severe peripheral vascular disease where even a low-flow arteriovenous fistula (AVF) may lead to severe symptoms and physical findings of DASS. Proximalization of arterial inflow for an existing vascular access is established as an effective treatment for DASS. We hypothesized that a primary proximal arterial inflow procedure for vascular access in patients judged to be at high risk for DASS would result in a successful hemodialysis access and mitigate the risk of steal syndrome. We report four such patients considered to be at significant risk for DASS after construction of a new vascular access. An axillary artery AVF inflow anastomosis was constructed in each patient. The access outflow configuration varied with the available venous outflow conduit identified during the preoperative ultrasound evaluation. In all four patients in this report, a functional autogenous dialysis access was established without DASS.

A Review of Femoral-Distal Bypass with Varicose Vein Covered by Prosthetic Mesh

The authors are to be congratulated for bringing the technique of wrapping suboptimal venous conduits with prosthetic meshes to our attention [1]. This technique is a valuable addition to our armamentarium in dealing with patients with critical limb ischemia.

Effective silencing of adhesion molecules on venous endothelial cells for protection of venous bypass grafts

The patency of venous conduits after aortocoronary bypass grafting is still not satisfactory and needs to be improved. Atherosclerotic alterations mediated by adhesion molecules triggering the transmigration of leukocytes are regarded as one of the major causes for venous graft failure. This study deals with short interfering RNA (siRNA)-mediated silencing of adhesion molecule expression on venous endothelial cells, which could lead to a new therapeutic strategy, resulting in improved patency rates by inhibiting early graft alterations. Primary human venous endothelial cells (HVECs) were cultured in a newly developed perfusion model and subsequently transfected with specific siRNAs targeting three different adhesion molecules (the E-selectin (ESELE), the intercellular adhesion molecule 1 (ICAM-1), and the vascular adhesion molecule (VCAM-1)), followed by stimulation with tumor necrosis factor-alpha (TNF-α). Isolated leukocytes were perfused under physiological shear stress conditions, and their attachment to HVEC after single and triple transfection was quantified. siRNA transfection effectively knocks down adhesion molecule expression on venous endothelial cells, which subsequently reduces leukocyte attachment. Leukocyte adhesion to activated HVEC was significantly reduced after transfection by specific siRNAs in each case compared to the controls (p<0.05). Transfection with a mixture of all three siRNA sequences improved this effect even more (p<0.05). For the first time, a functional protection of HUEC in a model simulating physiologic vascular conditions by using nonviral transfection of the cells in a setup with high relevance for clinical applicability was demonstrated. Therefore, siRNA transfection of bypass material may develop into a new therapeutic option to improve the quality of venous graft material in the future.

Open or Endovascular Repair of Secondary Aortoenteric Fistulae?

Secondary aortoenteric fistula (AEF) complicate 0.3e2.5% of all open aortic surgical procedures, with the incidence being lower following endovascular aortic aneurysm repair. It is, however, one of the most dangerous complications for a patient to encounter, with the highest mortality rates being observed in patients presenting with massive haemorrhage. In the past, patients with secondary AEF have usually been treated with total graft excision and either oversewing of the aortic stump and extra anatomic revascularisation or in-situ replacement with a rifampicin bonded prosthesis or (less commonly) deep venous conduits. Because of the considerable morbidity and mortality associated with these difficult and prolonged redo open procedures; the emergence of an endovascular solution has been actively welcomed. There are considerable theoretical attractions associated with the endovascular treatment of secondary AEF, most notably; reduced physiological stresses to the patient, shorter operating times, less trauma and reduced transfusion requirements, all of which translate into lower mortality and morbidity. However, following the publication of several small case series from around the world, there are now concerns that while the endovascular treatment of AEF may confer better short term outcomes, this may come with a heavy price in the long term. In effect; the endovascular treatment of secondary AEF may

Late improvement in graft patency after coronary artery bypass grafting: Serial assessment with multidetector computed tomography in the early and late postoperative settings

Grafts initially showing poor patency after coronary artery bypass grafting have occasionally shown improvement on serial multidetector computed tomography. This study analyzed possible factors associated with this phenomenon. Between September 2003 and July 2007, 512 patients underwent multidetector computed tomography within 1 month of isolated coronary artery bypass grafting. Among them, 1720 distal anastomoses were made with 1042 arterial and 302 venous conduits. Of these, 95 grafts (in 73 patients) were faint (n = 67) or nonvisualized (n = 28). Seventy-three of these grafts (in 56 patients) had follow-up multidetector computed tomographic evaluation 1 year after surgery and comprised the study group. Improvement in graft patency (faint to patent or nonvisualization to visualization) occurred in 44 grafts (60.3%). Multivariate analysis revealed proximal target vessel stenosis of at least 90% (relative risk, 3.81; P = .009), larger target coronary size (relative risk, 1.72; P = .002), and radial artery graft use (relative risk, 4.44; P = .003) to be significantly associated with the graft patency restoration. Graft patency restoration was most commonly observed in a group of 28 radial artery grafts that were anastomosed to target vessel with proximal stenosis of at least 90%; of these grafts, 24 (85.7%) showed improved graft patency on follow-up. A large proportion of radial artery grafts initially showing poor opacification after coronary artery bypass grafting demonstrated patency restoration on serial multidetector computed tomography. Larger target vessel size and target vessel stenosis of at least 90% were significant correlative factors.

Wall Shear Stresses Remain Elevated in Mature Arteriovenous Fistulas: A Case Study

Maintaining vascular access (VA) patency continues to be the greatest challenge for dialysis patients. VA dysfunction, primarily due to venous neointimal hyperplasia development and stenotic lesion formation, is mainly attributed to complex hemodynamics within the arteriovenous fistula (AVF). The effect of VA creation and the subsequent geometrical remodeling on the hemodynamics and shear forces within a mature patient-specific AVF is investigated. A 3D reconstructed geometry of a healthy vein and a fully mature patient-specific AVF was developed from a series of 2D magnetic resonance image scans. A previously validated thresholding technique for region segmentation and lumen cross section contour creation was conducted in MIMICS 10.01, allowing for the creation of a 3D reconstructed geometry. The healthy vein and AVF computational models were built, subdivided, and meshed in GAMBIT 2.3. The computational fluid dynamic (CFD) code FLUENT 6.3.2 (Fluent Inc., Lebanon, NH) was employed as the finite volume solver to determine the hemodynamics and shear forces within the healthy vein and patient-specific AVF. Geometrical alterations were evaluated and a CFD analysis was conducted. Substantial geometrical remodeling was observed, following VA creation with an increase in cross-sectional area, out of plane curvature (maximum angle of curvature in AVF=30 deg), and angle of blood flow entry. The mean flow velocity entering the vein of the AVF is dramatically increased. These factors result in complex three-dimensional hemodynamics within VA junction (VAJ) and efferent vein of the AVF. Complex flow patterns were observed and the maximum and mean wall shear stress (WSS) magnitudes are significantly elevated. Flow reversal was found within the VAJ and efferent vein. Extensive geometrical remodeling during AVF maturation does not restore physiological hemodynamics to the VAJ and venous conduit of the AVF, and high WSS and WSS gradients, and flow reversal persist. It is theorized that the vessel remodelling and the continued non-physiological hemodynamics within the AVF compound to result in stenotic lesion development.

Influence of tissue pressure on central venous pressure/peripheral venous pressure correlation: An experimental report

Peripheral venous pressure (PVP) has been shown to correlate with central venous pressure (CVP) in a number of reports. Few studies, however, have explored the relationship between tissue pressure (TP) and PVP/CVP correlation. PVP and CVP were simultaneously recorded in a bench-top model of the venous circulation of the upper limb and in a single human volunteer after undergoing graded manipulation of tissue pressure surrounding the intervening venous conduit. Measures of correlation were determined below and above a point wherein absolute CVP exceeded TP. Greater correlation was observed between PVP and CVP when CVP exceeded TP in both models. Linear regression slope was 0.975 (95% CI: 0.959-0.990); r (2) 0.998 above tissue pressure 10 cmH2O vs. 0.393 (95% CI: 0.360-0.426); and r (2) 0.972 below 10 cmH2O at a flow rate of 2000 mL/h in the in vitro model. Linear regression slope was 0.839 (95% CI: 0.754-0.925); r (2) 0.933 above tissue pressure 10 mmHg vs. slope 0.238 (95% CI: -0.052-0.528); and r (2) 0.276 in the en vivo model. PVP more accurately reflects CVP when absolute CVP values exceed tissue pressure.

Quantification of thermal spread and burst pressure after endoscopic vessel harvesting: A comparison of 2 commercially available devices

Endoscopic vein harvesting systems have grown in popularity and are becoming the gold standard for coronary artery bypass grafting. Although a consensus is present that endoscopic vessel harvesting minimizes wound complications, long-term graft patency remains a concern. It has been proposed that endoscopic vessel harvesting affects graft patency because of irreversible trauma to the endothelium. This study was performed to examine the extent of thermal injury caused by 2 commercially available endoscopic vessel harvesting systems in a porcine model. Superficial epigastric veins and saphenous arteries were exposed in 10 anesthetized swine. All vessel samples (conduits) were harvested randomly with either a VirtuoSaph (Terumo Cardiovascular, Ann Arbor, Mich) or VASOVIEW 6 (MAQUET, Inc, Wayne, NJ) endoscopic vessel harvesting system. Conduits were harvested and saved for either histologic analysis or burst-pressure test. Statistical differences were analyzed by using a Wilcoxon rank sum test in SAS 9.2 software (SAS Institute, Inc, Cary, NC) for thermal spread and a 2-tailed t test with equal variance for burst pressure. The average thermal spreads for saphenous artery and superficial epigastric vein conduits were significantly shorter in the VirtuoSaph group (0.42 ± 0.08 and 0.49 ± 0.05 mm, respectively) than in the VASOVIEW 6 group (1.05 ± .04 and 0.94 ± 0.19 mm, respectively). No significant differences were observed in burst pressure. The length of thermal spread is short in arterial and venous conduits (0.4-1.1 mm) and depends on the endoscopic vessel harvesting system. Clinical protocols should include a minimal length of the cauterized branch to ensure that thermal spread does not reach the main vessel. The results of this study suggest that at least 1 mm is sufficient.

A Challenging Case of Bilateral Iliopsoas Abscess

Bilateral iliopsoas abscess is very rare and has never been reported in cases of aortic graft infections. To date, only cases of unilateral abscess have been reported in association with aortic graft infection, and even these are uncommon. Case report and literature review. We present the first report of an infected abdominal aortic graft, secondary to an ileal perforation, in a 76-year-old woman presenting with bilateral iliopsoas abscess. The presence of lumbar spondylodiscitis initially led us to suspect this as the primary cause of the abscess. Hence, she was treated initially with drainage of the abscess, percutaneously and surgically. This proved to be unsuccessful. A laparotomy, excision of the aortic graft, and in situ revascularization with a femoral venous conduit was performed subsequently. The bilateral iliopsoas abscess was found to be caused by a perforation of the ileum. Despite the surgery, the patient finally succumbed. Bilateral iliopsoas abscess secondary to infected aortic graft is extremely rare and challenging. Drainage of the abscess, percutaneously or surgically, and excision of graft with or without revascularization must be considered carefully based on the individual case.

Carotid Artery Reconstruction for Infected Carotid Patches

Objectives Infected carotid prosthetic patches (ICPP) are a rare but catastrophic complication of carotid endarterectomy (CEA). Prevention and appropriate surgical management is essential. We report our experience of carotid artery reconstruction for ICPP. Design Single-center retrospective study. Methods 10-year review of the surgical treatment of ICPP. Results Twelve patients presented with patch infection following CEA. Three patients presented acutely with an expanding hematoma, eight with chronic complications (abscess/discharging sinus n = 5, carotid pseudoaneurysm n = 3). Mean age was 75 years. Replacement conduits included superficial femoral artery ( n = 6), cadaveric homograft ( n = 3), long saphenous vein ( n = 2) and one patient had primary closure. Five patients had muscle flaps fashioned for carotid artery protection. Operative complications included hypoglossal nerve injury (1 patient), superficial skin infection (2 patients) and one patient was returned to the operating room for a neck haematoma. Five surgical specimens were culture positive for: Staphylococcus aureus ( n = 3), Corynebacterium propionibacterium ( n = 1) and Streptococcus anginous ( n = 1). There were no 30-day mortalities. Mean hospital stay was 6 days. Median follow-up was 16 months (range 3–108 months). Conclusion Carotid artery reconstruction in a contaminated wound represents a significant surgical challenge. Unlike previous reports that used venous conduits, this is the first series where cadaveric or autologous arterial conduits were preferred. Arterial conduits achieved durable short term follow-up.

Brachial Artery Aneurysms Associated with Arteriovenous Access for Hemodialysis

Brachial artery aneurysm (BAA) is a rare condition. We describe a series of cases of BAA with arteriovenous access. Thirteen patients were retrospectively identified between January 2006 and July 2009 using a patient database. All were associated with brachio-cephalic fistulas. Mean age was 51.2 +/- 13.8 years. Twelve males (93.3%) were identified. Characteristics were: diabetes 1, hypertension 8, hypercholesterolemia 2, ischemic heart disease 2, family history of aneurysmal disease 2. Five BAA developed after access ligation, eight while it was working, one after trauma. One was associated with a venous aneurysm. While the average life of the access was 161 +/- 115 months, the average time for BAA formation was 40 +/- 35.8 months. BAA was asymptomatic in three patients, whereas 10 presented with ischemic and neurologic symptoms. None presented with a rupture. All patients underwent surgical repair, seven an aneurysm excision and end-to-end reconstruction of the brachial artery. Venous conduits were utilized: four long saphenous veins, one cephalic, and one basilic vein. All patients had patent brachial arteries with a complete relief of symptoms at 14 months. BAA is a rare but significant complication of vascular access. The surgical approaches presented offer a reasonable outcome.

RE: Regarding the ‘‘SAFARI’’ Technique: a Word of Caution

To the Editor, We read with great interest the letter from Lupattelli et al. [1]. We agree with the authors that when using the combined technique of subintimal arterial flossing with anteroretrograde intervention (SAFARI) in patients with critical limb ischemia (CLI) presenting with long-segment occlusions involving the superficial femoral, popliteal, and trifurcation arteries, it should be implemented with care and only in selected patients. Since the initial published experience by Spinosa et al. [2], we have performed this procedure on 45 limbs in patients with CLI. All patients had tissue loss (Rutherford 5/6) and were deemed not to have a reasonable operative option by an experienced vascular surgeon (i.e., no venous conduit, high risk for general anesthesia, or large wound at the distal bypass site). The median length of the occlusions in these 45 limbs was 30 cm. Technical success in providing in-line flow to the foot was achieved in 41 of 45 (90%) treated limbs. Access into the distal vessels was performed under ultrasound guidance using local anesthesia and a micropuncture set (Cook, Bloomington, IN, or AngioDynamics, Glen Falls, NY). The limb-salvage rate for technically successful cases was 78%, 71%, 57%, and 57% at 6, 12, 24, and 48 months, respectively [3]. In our experience, we did not encounter arterial dissection or thrombosis at the access site or distal emboli. The target vessels were studied carefully with ultrasound before retrograde arterial puncture, and a disease-free segment of the pedal or peroneal artery was accessed. The distal access site catheter diameter (i.e., the inner dilator of the transition dilator in a micropuncture set) was limited to 3F. Intra-arterial vasodilators, such as nitroglycerin, were liberally administered into the distal artery to minimize vasospasm. Appropriate anticoagulation is essential until in-line flow is established. Severe stenoses distal to the retrograde access site were treated through the antegrade access to maximize outflow. When the distal retrograde access was no longer needed, the catheter was removed, and light pressure was applied to the access site for 5 min, which was usually sufficient to obtain hemostasis. Open surgical access for the distal vessels was not necessary. Indeed, surgical access creates excess tissue trauma in these poorly perfused limbs, and we have not needed to employ open distal access in any of our patients. We agree that this procedure can be time-consuming in some cases, but use of the SAFARI technique has resulted in fairly rapid guidewire traversal of long-segment occlusion in patients in whom antegrade attempts to cross occlusions have proven to be difficult or have failed. In addition, the patients undergoing such procedures often have multiple comorbidities, including renal insufficiency and severe cardiac disease, and must be closely monitored during a potentially lengthy and stressful procedure. However, the stress on the cardiovascular system associated with the use of conscious sedation is much less than that associated with the general or epidural anesthesia used during open surgical revascularization. In our practice, the SAFARI technique is used primarily in patients with CLI when the main therapeutic alternative would be a major amputation or a high-risk distal bypass. Antegrade traversal of the occluded infrainguinal segments, most often from an ipsilateral antegrade approach, S. S. Sabri (&) J. F. Angle A. H. Matsumoto Department of Radiology, University of Virginia, Charlottesville, VA, USA e-mail: ss2bp@virginia.edu

A route for venous or free arterial conduits to the distal circumflex artery branches in coronary artery bypass operations

We describe a route for venous or free arterial conduits to the distal circumflex artery branches in coronary artery bypass operations. After constructing the distal anastomosis, open the space behind the inferior vena cava and pass the conduit through, in front of the right pulmonary vein to be anastomosed to the right side of the ascending aorta, anterior to the superior vena cava. This generates a lie of the conduit which allows it to sit in line with the target vessel (Fig. 1). Care must be taken to avoid conduit rotation as it passes behind the inferior vena cava.

EComment: Minimally invasive endoscope-enhanced venous conduit harvesting techniques

eComment: Minimally invasive endoscope-enhanced venous conduit harvesting techniques

Comparable patencies of the radial artery and right internal thoracic artery or saphenous vein beyond 5 years: Results from the Radial Artery Patency and Clinical Outcomes trial

To investigate the optimum conduit for coronary targets other than the left anterior descending artery, we evaluated long-term patencies and clinical outcomes of the radial artery, right internal thoracic artery, and saphenous vein through the Radial Artery Patency and Clinical Outcomes trial. As part of a 10-year prospective, randomized, single-center trial, patients undergoing primary coronary surgery were allocated to the radial artery (n = 198) or free right internal thoracic artery (n = 196) if aged less than 70 years (group 1), or radial artery (n = 113) or saphenous vein (n = 112) if aged at least 70 years (group 2). All patients received a left internal thoracic artery to the left anterior descending, and the randomized conduit was used to graft the second largest target. Protocol-directed angiography has been performed at randomly assigned intervals, weighted toward the end of the study period. Grafts are defined as failed if there was occlusion, string sign, or greater than 80% stenosis, independently reported by 3 assessors. Analysis is by intention to treat. At mean follow up of 5.5 years, protocol angiography has been performed in groups 1 and 2 in 237 and 113 patients, respectively. There are no significant differences within each group in preoperative comorbidity, age, or urgency. Patencies were similar for either of the 2 conduits in each group (log rank analysis, P = .06 and P = .54, respectively). The differences in estimated 5-year patencies were 6.6% (radial minus right internal thoracic artery) in group 1 and 2.9% (radial minus saphenous vein graft) in group 2. At mean 5-year angiography in largely asymptomatic patients, the selection of arterial or venous conduit for the second graft has not significantly affected patency. This finding offers surgeons, for now, enhanced flexibility in planning revascularization.

Technical Factors in Lower-Extremity Vein Bypass Surgery: How Can We Improve Outcomes?

Lower-extremity vein bypass surgery has been a standard operation in the armamentarium of vascular surgeons for more than 4 decades. Yet there remains surprising heterogeneity in the utilization, techniques, and outcomes associated with this procedure in current practice. Despite improvements in surgical technique and careful postoperative surveillance, vein graft failure remains a significant clinical problem affecting up to 50% of patients within 5 years. Experience, clinical judgment, creativity, and technical precision are required to optimize long-term results. Many factors, including patient-specific comorbidities, and variable biologic responses in the venous conduit, influence the ultimate outcome. Technical factors, however, play a dominant role in determining clinical success. Multiple single-center reports, and more recent multicenter trials, have clearly demonstrated that conduit selection and quality is the most critical element. An adequate caliber (>/=3.5 mm), good quality great saphenous vein is the optimal graft for infrainguinal bypass. Contralateral great saphenous vein, arm vein, and lesser saphenous vein are the next most desirable conduits. Graft configuration (reversed, nonreversed, or in situ) appears to have little influence on outcomes per se. Shorter grafts have improved patency. Inflow can be improved by surgical or endovascular means if necessary, and distal-origin grafts perform as well as those originating from the common femoral artery. The selected outflow vessel should supply unimpeded runoff to the foot, conserve conduit length, and allow for adequate soft-tissue coverage of the graft and a simplified surgical exposure. This review summarizes the data linking technical factors with graft patency, highlighting the importance of surgical judgment and operative planning in the current practice of infrainguinal bypass surgery.

Klippel-Trenaunay syndrome and radial artery coronary graft spasm.

A 75-year-old woman with known diagnosis of Klippel-Trenaunay syndrome presented with acute onset of chest pain, dyspnea and elevated cardiac enzymes. She had triple vessel coronary artery disease on subsequent coronary angiography. Given the unavailability of venous conduits secondary to lower extremity varicosities, coronary artery bypass grafting with radial and internal mammary arterial grafts was carried out. The radial artery graft went into spasm two days later and required intracoronary vasodilators to relieve the spasm. The patient remained hypotensive and finally expired.