Systematic literature review comparing clinical utility of heparin-bonded expanded polytetrafluoroethylene graft with autologous saphenous vein graft for the management of below-the-knee peripheral arterial disease.

BACKGROUND: This systematic literature review compares the clinical outcomes of heparin-bonded expanded polytetrafluoroethylene with autologous saphenous vein in the management of patients undergoing below-the-knee bypass to treat peripheral arterial disease. METHODS: An electronic literature search was conducted in MEDLINE and Embase to identify comparative studies in patients who underwent below-the-knee surgical bypass. Studies were screened at abstract and full text review using predefined inclusion criteria by two independent reviewers and critically appraised for risk of bias. Meta-analyses were conducted using Review Manager 5 software (Nordic Cochrane Centre). RESULTS: Eight retrospective cohort studies were identified. Meta-analysis of primary patency demonstrated no significant difference between heparin-bonded expanded polytetrafluoroethylene and autologous saphenous vein grafts after 1 (odds ratio: 0.91, 95% confidence interval: [0.52-1.59]; P = .74), 2 (1.12 [0.60-2.10]; P = .77), 3 (0.62 [0.26-1.48]; P = .28), and 4 years (0.70 [0.36-1.39]; P = .31). Similarly, for secondary patency, no significant difference was detected at 1 (0.62 [0.33-1.15]; P = .13), 2 (0.83 [0.32-2.13]; P = .69), 3 (0.60 [0.27-1.32]; P = .20), and 4 years (0.66 [0.32-1.36]; P = .26). There was no significant difference between autologous veins and heparin-bonded expanded polytetrafluoroethylene for limb salvage and mortality at all time points. A sensitivity analysis to compare outflow vessels was conducted in only tibial bypass and identified no differences. All analyses were considered at high-risk bias because of heterogeneity in study populations and attrition in follow-up. CONCLUSIONS: This meta-analysis demonstrates similar outcomes between autologous saphenous vein and heparin-bonded expanded polytetrafluoroethylene for patency, limb salvage, and mortality through 4 years. The use of heparin-bonded expanded polytetrafluoroethylene synthetic grafts is a satisfactory option to prevent amputation, particularly when autologous saphenous vein grafts are not available. Controlled clinical studies are needed to further inform future decision-making and economic modeling related to the choice of conduit for below-the-knee graft construction.

Management of peripheral arterial disease in the context of a multidisciplinary limb program.

Peripheral artery disease (PAD) continues to increase in prevalence worldwide due to risk factors such as advanced age, diabetes mellitus, and obesity. Critical limb ischemia (CLTI) is the advanced form of PAD that can result in a lack of healing and limb loss as the most devastating consequence. Patients with PAD, especially CLTI, benefit from multidisciplinary care to optimize outcomes by reducing cardiovascular morbidity and mortality and preventing lower extremity amputation. Collaboration between various specialties allows a focus on problems involved in treating the patient with PAD including prevention, screening, medical care, wound care, infection, and revascularization when needed. Although there is no clear definition or consensus on the structure of the PAD team, certain guidelines are applicable to most clinical scenarios emphasizing "provider champions" in leading a clinical program. A vascular specialist (vascular surgery, interventional radiology, interventional cardiology) and a soft tissue specialist (podiatry, plastic surgery) are the typical "champions," often involving orthopedics, general surgery, vascular medicine, diabetology/endocrinology, infectious disease, nephrology, and rehabilitation medicine. The team should also include wound nurses, nutritionists, occupational therapists, orthotists, pharmacists, physical therapists, prosthetists, and social workers. This paper presents a brief overview of the structure of the multidisciplinary team with key components and functions of such a team to optimize treatment outcomes for PAD and CLTI.

Surgical Deep Vein Arterialization: Adding to the Armamentarium of Complex Limb Salvage.

BACKGROUND: Patients with severe peripheral arterial disease with limited or nonexistent arterial runoff, the so-called "desert foot", challenge efforts at limb preservation. Deep vein arterialization (DVA) involves incorporating a venous target as an outflow to achieve revascularization in these complex patients. We report outcomes in an initial series of patients undergoing DVA as a component of surgical bypass. METHODS: Over a 2-year period, 10 patients underwent bypass incorporating DVA due to severely disadvantaged runoff using a heparin-bonded expanded polytetrafluoroethylene conduit. Indications for surgery included tissue loss (8) or ischemic rest pain (2) in patients who had failed endovascular (3) or surgical (7) revascularization. Inflow arteries for bypass ranged from external iliac to below knee popliteal. Outflow anastomoses incorporated a common ostium arteriovenous fistula between anterior tibial (5), posterior tibial (2), peroneal (1) or plantaris pedis (2) arteries, and corresponding tibial veins. Prior to anastomotic completion, tibial vein valves were lysed to allow venous arterialization by a way of retrograde flow. Postoperative medical regimen included dual antiplatelet (2), antiplatelet plus anticoagulation (7), or anticoagulation alone (1). RESULTS: Primary patency was maintained in 7 of 10 grafts (average: 4.1 months, range: 1-18 months). Limb salvage was achieved in 8 of 10 patients (average: 6 months, range: 1-18 months). Two below knee amputations were performed after graft occlusion due to extensive tissue loss and infection, whereas 1 patient maintained limb salvage despite graft occlusion after successful wound healing. CONCLUSIONS: This initial experience describes surgical DVA using a prosthetic conduit in conjunction with an arteriovenous fistula at the distal anastomosis in patients with threatened limb loss and severely disadvantaged tibial runoff. Although evidence for long-term efficacy is uncertain, preliminary outcomes warrant further investigation as this technique may allow for surgical revascularization resulting in limb preservation for patients with no other alternative than amputation.

Learning curve and proficiency metrics for transcarotid artery revascularization.

BACKGROUND: When introduced to a new procedure, physicians improve their performance and reduce their procedural adverse event rates rapidly during the initial cases and then improvement slows, signaling that proficiency has been achieved. Determining when they have acquired proficiency has important implications for procedural innovation, education, credentialing, and patient safety. We analyzed the worldwide experience with transcarotid artery revascularization (TCAR), a hybrid approach to carotid revascularization, to identify the (1) procedural performance measures associated with clinical and technical adverse events; (2) target levels of performance measures that minimize adverse event rates; and (3) number of TCAR cases needed to achieve the target levels for the performance measures. METHODS: The patient, lesion, and physician characteristics were collected for each TCAR procedure performed by each physician worldwide in an international quality assurance database. Four procedural performance measures were recorded for each procedure: flow-reversal time, fluoroscopy time, contrast volume, and total skin-to-skin time. Composite clinical adverse events (ie, transient ischemic attack, stroke, myocardial infarction, death) and composite technical adverse events (ie, aborted procedure, conversion to surgery, bleeding, dissection, cranial nerve injury, device failure), occurring within 24 hours were also recorded. Correlations between each performance measure and the clinical and technical adverse event rates were computed. The inflection points in the performance measures were identified at which no further improvements occurred in the adverse event rates. Finally, the minimum number of TCAR cases required to achieve the target performance measure levels was computed. RESULTS: A total of 18,240 procedures performed by 1273 physicians were analyzed. Of the 18,240 patients, 34.9% were women and 62.5% were asymptomatic. The flow-reversal time correlated with clinical adverse events adjusted for age, sex, and symptomatic status (R2 = 0.91; P < .0001) and adjusted technical adverse events (R2 = 0.86; P < .0001). The skin-to-skin time correlated with adjusted technical adverse events (R2 = 0.92; P < .0001). A reduction in flow-reversal times to <13.1 minutes and the skin-to-skin time to <81 minutes did not translate into further improvements in the adverse event rates. A minimum of 26 TCAR cases was required to achieve the target flow-reversal time, and a minimum of 15 cases was required to achieve the target skin-to-skin time. CONCLUSIONS: The flow-reversal time and skin-to-skin time are appropriate performance measures for establishing the level of expertise of physicians as they acquire skills to perform TCAR. A target time of ≤13.1 minutes for flow-reversal and 81 minutes for skin-to-skin time minimized the adverse event rates. Familiarity with the steps involved in performing TCAR was achieved after ≥15 cases, and minimizing clinical adverse events occurred after ≥26 cases.

Modern multidisciplinary team approach is crucial in treatment for critical limb threatening ischemia.

The aim of this study was to provide a brief overview of the history the multidisciplinary team approach, highlighting the benefit to the patient with critical limb threatening ischemia in relation to health care economics. Furthermore, we provided a description of the requisites and key components, showing how to build a multidisciplinary team.

Determinants of Long-Term Outcomes and Costs in the Management of Critical Limb Ischemia: A Population-Based Cohort Study.

Background The optimal treatment for critical limb ischemia remains controversial owing to conflicting conclusions from previous studies. Methods and Results We obtained administrative claims on Medicare beneficiaries with initial critical limb ischemia diagnosis in 2011. Clinical outcomes and healthcare costs over 4 years were estimated among all patients and by first treatment (endovascular revascularization, surgical revascularization, or major amputation) in unmatched and propensity-score-matched samples. Among 72 199 patients with initial primary critical limb ischemia diagnosis in 2011, survival was 46% (median survival, 3.5 years) and freedom from major amputation was 87%. Among 9942 propensity-score-matched patients (8% rest pain, 26% ulcer, and 66% gangrene), survival was 38% with endovascular revascularization (median survival, 2.7 years), 40% with surgical revascularization (median survival, 2.9 years), and 23% with major amputation (median survival, 1.3 years; P<0.001 for each revascularization procedure versus major amputation). Corresponding major amputation rates were 6.5%, 9.6%, and 10.6%, respectively ( P<0.001 for all pair-wise comparisons). The cost per patient year during follow-up was $49 700, $49 200, and $55 700, respectively ( P<0.001 for each revascularization procedure versus major amputation). Conclusions Long-term survival and cost in critical limb ischemia management is comparable between revascularization techniques, with lower major amputation rates following endovascular revascularization. Primary major amputation results in shorter survival, higher risk of subsequent major amputation, and higher healthcare costs versus revascularization. Results from this observational research may be susceptible to bias because of the influence of unmeasured confounders.

Development of a Limb-Preservation Program.

In the global scenario, as the prevalence of renal failure and diabetes increases, healing and limb preservation assume increasing clinical importance for patients and healthcare systems. Unfortunately, there continues to be variation in the care delivered to patients at risk of losing a limb based on geography, race, socioeconomic status, and insurance status. There are also a variety of therapeutic approaches to patients with limb-threatening ischemia; 25% undergo primary amputation, 25% undergo medical therapy, and only 50% undergo any attempt at revascularization. Nearly 50% of patients undergoing major amputation have not had a simple diagnostic arteriogram to assess the possibility of limb preservation. The Society of Vascular Surgery and the American Podiatric Medical Association have recognized the benefits of a multidisciplinary approach to limb preservation. Benefits to the patient include rapid assessment, improved healing, and enhanced revascularization. Advantages for the providers include the ability to efficiently manage complex patients with help from the appropriate specialties, an increase in referrals, enhanced identity of the institution, and clinical research and trials. Such a program requires the coordinated effort of physicians, nurses, allied health professionals, and administrators dedicated to the preservation of functional limbs. Beneficial components include identifiable space, a vascular laboratory, hyperbaric oxygen therapy, and protocol-driven care involving diagnostic and therapeutic modalities such as endovascular revascularization, open bypass, and soft tissue reconstruction. Prosthetic expertise is also important to maintain function in those patients for whom amputation is appropriate. But, the key to a program is cooperation and communication among the participants who have a passion for limb preservation. Video Journal Club 'Cappuccino with Claudio Ronco' at http://www.karger.com/?doi=452746.

Initial in vitro and in vivo evaluation of a self-monitoring prosthetic bypass graft.

OBJECTIVE: Prosthetic grafts used for lower extremity revascularization and dialysis access fail because of hyperplastic stenosis and thrombosis. Graft surveillance is advocated to monitor function; however, graft failure can occur between episodic examinations. An innovative sensor with wireless, microchip technology allows automated surveillance with assessment of graft function using a "cloud"-based algorithm. We performed proof-of-concept experiments with in vitro and in vivo models to assess the feasibility such a real-time graft surveillance system. METHODS: A self-monitoring graft system was evaluated consisting of a prosthetic conduit of expanded polytetrafluoroethylene and a sensor unit, and a microsensor, microelectronics, battery, and remote processor with a monitor. The sensor unit was integrated on the extraluminal surface of expanded polytetrafluoroethylene grafts without compromise to the lumen of the conduit. The grafts were tested in vitro in a pulsatile, recirculating flow system under physiologic flow parameters. The hemodynamic parameters were varied to assess the ability to obtain wireless signal acquisition reflecting real-time flow properties in vitro. Segments of custom tubing with reduced diameters were inserted into the model to mimic stenosis proximal and distal to the grafts. After characterization of the initial data, the self-monitoring grafts were implanted in an ovine carotid model to assess proof of concept in vivo with 30-day follow-up of signal acquisition as well as arteriographic and histologic analysis. RESULTS: In vitro flow data demonstrated the device was able to determine factors related to prosthetic graft function under varied hemodynamic flow conditions. Wireless signal acquisition using Bluetooth technology (Bluetooth SIG, Inc, Kirkland, Wash) allowed remote data analysis reflecting graft flow parameters through changes in microsensor voltage and frequency. Waveform analysis was applied to construct an algorithm using proprietary software and determine a parameter for graft flow characteristics. This algorithm allowed determination of the degree of stenosis and location of stenosis location (proximal or distal) for display on a remote monitor in real time. Subsequent in vivo experiments confirmed the ability of the system to generate signal acquisition through skin and soft tissue under biologic conditions with no arteriographic stenosis and a favorable healing response at 30-day harvest. CONCLUSIONS: Initial in vitro and in vivo experiments demonstrate the ability for a self-monitoring graft system to remotely monitor hemodynamic parameters reflecting graft function using wireless data transmission. This automated system shows promise to deliver real-time data that can be analyzed by cloud-based algorithms alerting the clinician of a change in graft function or development of stenosis for further diagnostic study or intervention before graft failure.

Postoperative complications after common femoral endarterectomy.

BACKGROUND: Common femoral endarterectomy (CFE) for limited arterial occlusive disease is considered a fairly low-risk operation of short duration. This study investigated the timing of 30-day outcomes as they related to hospital discharge and predicted the risk of operative mortality of this procedure. METHODS: All patients in the National Surgical Quality Improvement Program database who underwent isolated CFE between 2005 and 2010 were selected for the test sample. We identified postoperative mortality and morbidities occurring before and after hospital discharge. A risk calculator for 30-day mortality, developed in the test sample using logistic regression, was validated in a new sample of cases from 2011 to 2012. RESULTS: A total of 1843 CFEs reported from 2005 to 2010 met the inclusion and exclusion criteria. The average operative time was 146 ± 69.5 minutes (median, 133; interquartile range, 98-179 minutes), and 10% of patients needed to return to the operating room. The average length of stay was 4 ± 7.5 days (median, 3; interquartile range, 2-5 days); 91% of patients were discharged ≤ 1 week of surgery. Occurrences of cardiovascular events, renal dysfunction, and pulmonary complication were relatively low. There was 3.4% mortality and 8% wound-related complications, 30% and 86% of which occurred after hospital discharge, respectively. Overall, there was a 15% risk of combined mortality/morbidity, and >60% of these events occurred after discharge. The independent predictors of 30-day mortality were age, nonindependent functional status, preoperative dialysis, sepsis, emergency status, and American Society of Anesthesiologists Physical Status Classification 4 or 5, and the association between risk strata and death in the validation sample was strong (φ = 0.29) and significant (P < .001). CONCLUSIONS: CFE is not as "benign" a procedure as previously believed. The risks of death and wound complications are not insignificant, and a high percentage of these complications occurred after patients were discharged from the hospital. Patients should be carefully selected, especially in the elderly population, and close postoperative follow-up should be considered.

Celiac artery compression after a gastric bypass.

Median arcuate ligament (MAL) syndrome or celiac artery compression occurs secondary to diaphragmatic compression of the celiac artery and the corresponding neural structures of the celiac plexus. Typically, patients present with postprandial abdominal pain, nausea, vomiting, and weight loss. Diagnostically, various radiologic studies are used to document impingement of the celiac artery including ultrasound, computed tomography, aortograms, and magnetic resonance imaging. Historically, open approaches to the aorta and the celiac artery are performed to release the MAL and relieve compression of the celiac artery and the plexus. Laparoscopic approaches are now utilized to divide the MAL. This study describes a patient who underwent a successful laparoscopic Roux-en-Y gastric bypass and lost 100 lbs over a 2-year postoperative period. Subsequently, the patient developed postprandial abdominal pain associated with nausea. She underwent a computed tomogram that diagnosed celiac compression and then a dynamic ultrasound that showed elevated velocities with deep expiration. Ultimately, a laparoscopic MAL release with division of the celiac plexus was performed. At 10 months postoperatively, the patient remains asymptomatic. To our knowledge, this report documents a rare case of CAC after Roux-en-Y gastric bypass. On the basis of this report, CAC should be considered in the differential diagnosis of postprandial abdominal pain in patients after bariatric surgery.

The effect of graft configuration on 30-day failure of infrapopliteal bypasses.

BACKGROUND: Despite advances in endovascular techniques, infrapopliteal bypasses are still required for limb salvage. Short-term graft patency is an important outcome parameter reflecting technical considerations and acute graft thrombosis. Both are important prerequisites for long-term patency. In this analysis, we compared the 30-day patency of all conduit configurations for infrapopliteal bypasses. METHODS: All primary infrapopliteal bypasses from the American College of Surgeons-National Surgical Quality Improvement Program database between 2005 and 2010 were divided into six groups: (1) great saphenous vein (GSV); (2) prosthetic conduit (prosthetic); (3) prosthetic conduit with a distal anastomotic venous adjunct (ADJ), such as a cuff or patch (prosthetic + ADJ); (4) composite graft of prosthetic and a vein segment (composite); (5) spliced autogenous vein (spliced vein); and (6) arm vein. Thirty-day graft failure, patient demographics, and operative details were compared among groups. A multivariate model was used for statistical analysis. RESULTS: A total of 5375 infrapopliteal bypasses were analyzed by conduit: GSV, 3983 (75%); prosthetic, 898 (17%); spliced vein, 160 (3%); prosthetic + ADJ, 112 (2%); arm vein, 93 (2%); and composite, 91 (2%). The difference among groups in demographics and comorbidities was not statistically significant. Perioperative mortality rates were similar among different conduits. After adjusting for sex, age, weight, race, and previous cardiac surgery, the bypass conduit had a significant independent association with 30-day graft patency (P = .006). The GSV failure rate was 7.5%. Composite had a significantly higher 30-day failure rate (15.4%, P = .006). There was no significant difference in 30-day failure rate of spliced vein (5.6%, P = .37) or arm vein (4.3%, P = .24) conduits compared with GSV. Prosthetic had significantly higher 30-day failure rate than GSV (10.5%, P = .004). The addition of adjuvant venous tissue at the distal anastomosis of prosthetic bypasses did not significantly improve their 30-day patency (failure rate of 9.8% for prosthetic + ADJ and 10.5% for prosthetic). There was no significant difference in graft patency between alternative venous conduits (arm vein/spliced vein) and prosthetic + ADJ. CONCLUSIONS: Venous conduits (GSV, spliced vein, arm vein) deliver the best 30-day patency for infrapopliteal bypasses, and GSV remains the most commonly used graft. Prosthetic grafts had a higher 30-day failure rate. Composite grafts should be abandoned because their early patency is not better than pure prosthetic conduits. The addition of a distal venous adjunct did not seem to improve acute prosthetic graft patency, which may reflect lack of effect on thrombogenicity rather than the myointimal hyperplastic response that effects long-term failure of infrapopliteal bypass.

Comparison of outcomes for open abdominal aortic aneurysm repair and endovascular repair in patients with chronic renal insufficiency.

OBJECTIVE: This study investigates whether this practice is supported by multicenter prospectively collected data. BACKGROUND: Currently, open abdominal aortic aneurysm (AAA) repair (OPEN) is preferred over endovascular repair (EVAR) in patients with chronic renal insufficiency because of the concern that the contrast load used for EVAR may result in postoperative dialysis. METHODS: Patients who underwent EVAR and OPEN for infrarenal AAA were identified in the NSQIP database from 2005 to 2010. Preoperative renal function was assessed by estimated glomerular filtration rate (eGFR) calculated by the Chronic Kidney Disease Epidemiology Collaboration equation. Patients with chronic renal insufficiency were further stratified into 2 different groups: moderate (eGFR = 30-60 mL/min) and severe (eGFR <30 mL/min) renal dysfunction. Multivariate regression model was used for data analysis. RESULTS: We identified 13,191 patients who underwent AAA repair: 9877 patients underwent EVAR and 3314 underwent OPEN. Forty percent of patients had eGFR of less than 60 mL/min. OPEN in patients with moderate renal dysfunction resulted in significantly higher mortality, cardiovascular events, and combined outcomes. However, in patients with severe renal dysfunction, these outcomes were similarly high in both OPEN and EVAR. Most importantly, OPEN in patients with moderate renal dysfunction resulted in 5.2 times higher risk of dialysis. CONCLUSIONS: Contrary to current practice, and despite the use of contrast, EVAR should be the first choice in patients with moderate renal dysfunction if they have the appropriate anatomy. Higher threshold for AAA repair with either OPEN or EVAR should be applied in patients with severe renal dysfunction because postoperative complications were significantly high with either approach.

Surgical bypass: when is it best and do angiosomes play a role?

The etiology of foot lesions in diabetics is multifactorial. Arterial insufficiency, neuropathy, and susceptibility to infection are major factors contributing to the formation of nonhealing diabetic foot lesions. These factors lead to a 15% ulceration rate in diabetics with 20% resulting in amputation. This amputation rate, 4.1 per 1,000 per year, represents a risk 40 times greater for diabetics, with a subsequent second amputation in 60% by 5 years. Conversely, more than half of all lower-extremity amputations are performed in diabetic patients. Therefore, the primary goal in diabetic lower-extremity care is to heal foot ulcerations and prevent amputations and major disabilities. Lower-extremity revascularization is a major facet of achieving the goal of healing and amputation prevention. Due to the severity, distribution, and complexity of diabetic vascular disease, surgical bypass continues to play a role in attaining this goal. Surgical bypass might be the best option for diabetic patients with significant tissue loss or to revascularize the appropriate angiosome of the foot and maximize healing potential. In order to offer surgical bypass to these patients, innovative techniques might need to be considered, including venous patches and cuffs, heparin-bonded grafts, and adjunctive distal arteriovenous fistulas.