Bruce A. Snyder

Prosthetic thigh arteriovenous access: outcome with SVS/AAVS reporting standards

PURPOSEnDifferences in the reporting methods of results for arteriovenous (AV) access can dramatically affect apparent outcome. To enable meaningful comparisons in the literature, the Society for Vascular Surgery and the American Association for Vascular Surgery (SVS/AAVS) recently published reporting standards for dialysis access. The purpose of the present study was to determine infection rates, patency rates, and possible predictive factors for prosthetic thigh AV access outcomes with the reporting standards of the SVS/AAVS.nnnMETHODSnA retrospective analysis was performed of all patients who underwent placement of thigh AV access by the Surgical Teaching Service at Greenville Memorial Hospital between 1989 and 2001. Outcomes were determined based on SVS/AAVS Standards for Reports Dealing with AV Accesses. The rate of revision per year of access patency was also determined; this end point more accurately reflects the true cost and morbidity associated with AV access than do patency or infection rates alone.nnnRESULTSnOne hundred twenty-five polytetrafluoroethylene thigh AV accesses were placed in 100 patients. Nine accesses were excluded from the study, six because there was no patient follow-up and 3 as a result of deaths unrelated to the access procedure and which occurred less than 30 days after access placement. There were six (4%) late access-related deaths. There were 18 (15%) early access failures, related to infection in 14 cases (12%), thrombosis in three cases (2%), and steal in one case (1%). Early failure was more common in patients with diabetes mellitus (P =.036). The primary and secondary functional patency rates were 19% and 54%, respectively, at 2 years. Infection occurred in 48 (41%) accesses. The patency and infection rates were not influenced by patient age, gender, body mass index, or diabetes mellitus. The median number of interventions per year of access patency was 1.68, and this outcome was positively correlated with body mass index (P <.001).nnnCONCLUSIONSnProsthetic AV access in the thigh is associated with higher morbidity compared with that reported for the upper extremity, and should be considered only if no upper extremity AV access option is available. Early access failure and the requirement for an increased number of interventions to reestablish and maintain access patency are more common in patients with diabetes mellitus and obesity. The number of interventions per year of access patency is a valuable end point when assessing the outcome of AV access procedures.

Can the Perclose suture-mediated closure system be used safely in patients undergoing diagnostic and therapeutic angiography to treat chronic lower extremity ischemia?

PURPOSEnMechanical closure devices for arterial hemostasis after angiography, such as the Perclose suture-mediated closure system, are designed to decrease time to ambulation and improve patient comfort. Although these devices are safe and efficacious, to date there has been little reported about use of the Perclose device in a cohort consisting exclusively of patients with lower extremity peripheral vascular disease. The purpose of this study was to determine the safety and efficacy of routine use of the Perclose system in patients with documented peripheral vascular disease undergoing angiography to treat chronic lower extremity ischemia.nnnMETHODSnThe Perclose device was placed for arterial closure after femoral artery access in 500 consecutive patients with documented peripheral vascular disease (ankle-brachial index, <0.8) who underwent diagnostic angiography or percutaneous intervention because of chronic lower extremity ischemia. These 500 patients composed 91% of all patients who underwent angiography because of chronic lower extremity ischemia between January 1, 2001, and April 1, 2002. All complications associated with the Perclose device were identified and reviewed.nnnRESULTSnOf the 500 arteries, 54% were accessed for diagnostic angiography and 46% for intervention. Perclose device placement was successful in 475 attempts (95%). Overall major complication rate was 1.4% (7 of 500 arteries). Complications included one death from retroperitoneal hemorrhage; three episodes of limb ischemia, two requiring operation and one requiring lytic therapy; two pseudoaneurysms; and one hematoma, which prolonged hospitalization. The hematoma was the only complication in the 25 patients with failed Perclose device placement. There were no infections requiring admission or operation.nnnCONCLUSIONnThe Perclose suture-mediated closure device is efficacious and can be used safely in selected patients with documented peripheral vascular disease. Complications associated with this device tend to be more severe than those historically reported for manual compression. Substantial experience with use of this device is required to achieve excellent results in patients with difficult anatomy.

The LEGS Score: A Proposed Grading System to Direct Treatment of Chronic Lower Extremity Ischemia

ObjectiveTo prospectively compare the Lower Extremity Grading System (LEGS)-derived “recommended treatment” to the actual treatment performed and to analyze LEGS intergrader scoring consistency by comparing blinded scoring results between physician graders. Summary Background DataDue to technical advances and the increased medical complexity of the aging population, the most appropriate treatment for chronic lower extremity ischemia—open surgery versus endovascular—is again in flux. In an attempt to standardize management, the LEGS score, based on the best available outcomes data, was devised by the physicians of an established vascular service. MethodsFrom March to June 2002, all chronically ischemic lower extremities that met standard indications for revascularization were prospectively enrolled and independently graded with the LEGS score by an “endovascular surgeon” and an “open surgeon” for comparative analysis. The results were then blindly evaluated to determine whether the LEGS-derived “recommended treatment” agreed with the actual treatment rendered and to assess for intergrader consistency. Agreement was assessed using kappa statistical analysis. ResultsOf the 137 presenting limbs (mean patient age 66.4 yo; 43% claudication, 57% limb-threatening ischemia), 107 were treated (65% endovascular, 30% open surgery, 5% amputation), 16 were pending treatment, and 14 were not treated because of patient refusal (n = 13) or death (n = 1). The LEGS score predicted the actual or offered clinical treatment in 90% of cases. The LEGS score comparison between physician graders resulted in identical “recommended treatment” in 116 of 128 cases for a 90.6% agreement. ConclusionsA reproducible scoring system to guide the treatment of patients with chronic lower extremity ischemia is possible. While systems like the LEGS score may have potential clinical application, their use as a treatment standardization tool for future prospective outcomes comparisons between open and endovascular surgery will be essential.

Do Current Outcomes Justify More Liberal Use of Revascularization for Vasculogenic Claudication? A Single Center Experience of 1,000 Consecutively Treated Limbs

BACKGROUNDnThe purpose of this study was to reconsider current recommended treatment guidelines for vasculogenic claudication by examining the contemporary results of surgical intervention.nnnSTUDY DESIGNnWe performed a retrospective review of 1,000 consecutive limbs in 669 patients treated for medically refractory vasculogenic claudication and prospectively followed. Outcomes measured included procedural complication rates, reconstruction patency, limb salvage, maintenance of ambulatory status, maintenance of independent living status, survival, symptom resolution, and symptom recurrence.nnnRESULTSnOf the 1,000 limbs treated, endovascular therapy was used in 64.3% and open surgery in 35.7% of patients; aortoiliac occlusive disease was treated in 70.1% and infrainguinal disease in 29.9% of patients. The overall 30-day periprocedural complication rate was 7.5%, with no notable difference in complication rates when comparing types of treatment or levels of disease. Overall reconstruction primary patency rates were 87.7% and 70.8%; secondary patencies were 97.8% and 93.9%; limb salvage, 100% and 98.8%; and survivals, 95.4% and 76.9%, at 1 and 5 years, respectively. More than 96% of patients maintained independence and ambulatory ability at 5 years. Overall symptom resolution occurred in 78.8%, and symptom recurrence occurred in 18.1% of limbs treated, with slightly higher resolution and recurrence noted in patients treated with endovascular therapy.nnnCONCLUSIONSnContemporary treatment of vasculogenic claudication is safe, effective, and predominantly endovascular. These data support a more liberal use of revascularization for patients with claudication and suggest that current nonoperative treatment guidelines may be based more on surgical dogma than on achievable outcomes.

An analysis of limb-threatening lower extremity wound complications after 1090 consecutive coronary artery bypass procedures

The objective of this study was to examine and characterize limb-threatening lower extremity wound or soft tissue complications after coronary artery bypass (CABG) and determine risk factors for their cause. While minor wound problems of the leg after CABG are not uncommon, serious limb-threatening complications, though less frequent, do occur and are often de-emphasized in the surgical literature. A review of 1090 consecutive CABG procedures performed from January 1, 1995 through December 31, 1995 was instituted, which screened for limb-threatening lower extremity wound or soft tissue complications defined as wounds that: required additional surgery for treatment; prolonged the length of stay; or which required lengthy home health nursing for treatment. Minor lymph leaks, leg swelling, infections or wound problems treated as an outpatient were excluded. Of 1090 patients, 54 (5.0%) experienced a limb-threatening lower extremity complication. Complications were categorized as vein harvest incision non-healing (n = 36, 66.7%), decubitus ulceration (n = 11, 20.4%), forefoot ischemia/embolization (n = 10, 18.5%), groin hematoma/abscess (n = 6, 11.1%), severe cellulitis (n = 3, 5.6%), or a combination (n = 12, 22.2%). Statistically significant risk factors by univariate and bivariate analysis for a complication included older age (68 years vs 62 years, p = 0.007), female sex (57% vs 28%, p, 0.001), diabetes (57% vs 33%, p = 0.005) and longer pump time (129 min vs 114 min, p = 0.009). These complications necessitated five major lower extremity amputations and nine revascularization procedures. Chronic lower extremity ischemia from peripheral vascular disease (PVD) was a major contributing factor for the development of wounds in at least 23 (42.6%) of these patients, though suspected in only 10 (43.5%) preoperatively. A non-healing vein harvest incision below the knee of a patient retrospectively found to have inadequate distal circulation for healing occurred in 17 (31.5%) of the total 54 cases. It was concluded that non-healing vein incisions, decubitus ulcers and forefoot ischemic lesions frequently occurring in older diabetic females with undetected pre-existing PVD, comprise the majority of limb-threatening leg complications after CABG. Nearly one-third of the complications may have been avoided had the vein harvest incision not been made at the ankle of a patient with unappreciated PVD.

A reappraisal of a modified through-knee amputation in patients with peripheral vascular disease

BACKGROUNDnThrough-knee amputation provides a longer lever arm and improved muscle control of the limb compared with above-knee amputation. Through-knee amputation also allows use of a total end-bearing prosthesis, which avoids the ischial pressure and suspension belts required of the above-knee amputation prosthesis. Several reports in the European literature tout the superiority of the through-knee amputation over the above-knee amputation in the patient with vascular disease. Through-knee amputation has received little attention in the United States, however, owing to the belief that the long flaps necessary to close a standard through-knee amputation are associated with an unacceptable rate of wound problems and offer no functional ambulatory advantage to above-knee amputation. We reviewed our experience with a modified technique of through-knee amputation in a group of patients with severe lower extremity ischemia who were not candidates for below-knee amputation to determine the incidence of wound complications and their functional outcome.nnnMETHODSnSince 1996, 12 patients with severe lower extremity arterial insufficiency have undergone through-knee amputation utilizing a technique designed to limit flap length and facilitate the fit of a suction prosthesis. Two patients died of myocardial infarction in the immediate postoperative period and were excluded from the study. In the remaining 10 patients (1 man, 9 women; mean age 63 years (range 40 to 86), the below-knee amputation level was precluded because of gangrene or nonhealing wounds of the mid leg in 5 patients, failure of a previous below-knee amputation attempt in 4 patients, and severe ischemia that would compromise below-knee amputation healing in 1 patient. Nine patients had at least one failed vascular reconstruction procedure.nnnRESULTSnMean follow-up is 25 months (range 6 to 41). Six (60%) patients had primary healing of their amputations. Two (20%) patients had delayed healing (6 weeks and 8 weeks). Two (20%) patients developed wound infections, which required amputation revision to the above-knee level. Seven (70%) patients were fitted with a suction socket prosthesis and are fully ambulatory. One patient healed but has not ambulated because of ischemia and subsequent ulceration of the contralateral limb.nnnCONCLUSIONSnThese data show that through-knee amputation is associated with an acceptable primary healing rate (80%) and satisfactory functional outcomes (70% ambulation) in a high-risk vascular population. The functional advantages of through-knee amputation over above-knee amputation make it the preferred alternative for patients with vascular disease.

Superficial femoral artery eversion endarterectomy: A useful adjunct for infrainguinal bypass in the presence of limited autogenous vein

PURPOSEnTo evaluate, in a group of technically high-risk patients, the results of infrainguinal revascularization using a conduit constructed with endarterectomized superficial femoral artery (SFA) and available arm or saphenous vein.nnnMETHODSnOf 237 consecutive lower extremity vein graft bypass procedures performed in 195 patients from July 1992 through August 1996, 15 SFA eversion endarterectomies (in 10 men and five women; median age, 70 years) were performed and used as a composite bypass conduit with available autogenous vein for the treatment of limb-threatening ischemia. In each case, an occluded SFA was divided 8 to 15 cm distal to its origin, proximally endarterectomized, and sewn end-to-end to a segment of vein to provide adequate conduit length for bypass grafting. Indications for this technique were unavailability of vein as a result of failed previous bypass grafting (n = 10) or previous coronary artery bypass grafting (n = 5). Veins were sewn distally to a below-knee popliteal artery (n = 4; 27%) or tibial artery (n = 11; 73%).nnnRESULTSnPrimary patency, secondary patency, and limb salvage rates at 36 months by life table analyses for the 237 grafts were 62.3%, 81.0%, and 77.2%, respectively. The 15 composite SFA-vein bypass grafts had 36-month primary patency, secondary patency, and limb salvage rates of 60.0%, 72.0%, and 65.9%, respectively (mean follow-up, 15 months). Currently, eight of these patients (53%) have patent bypass grafts; two (13%) died at 4 and 18 months after the operation with patent grafts; two (13%) underwent amputations for progressive foot gangrene despite a patent bypass graft; and three (20%) had grafts that thrombosed at 4, 5, and 10 months. Typical hyperplastic intrinsic graft-threatening stenoses developed in two patients (13%) in the SFA segment at 4 and 8 months; they were discovered by routine duplex scan surveillance.nnnCONCLUSIONnComposite SFA eversion endarterectomy/vein graft conduits yield acceptable results, behave similarly to other autogenous conduits used for technically high-risk infrainguinal revascularization, and are beneficial when autogenous vein is limited.

Characterization of fracture behavior of human atherosclerotic fibrous caps using a miniature single edge notched tensile test

UNLABELLEDnOne well-established cause of ischemic stroke is atherosclerotic plaque rupture in the carotid artery. Rupture occurs when a tear in the fibrous cap exposes highly thrombogenic material in the lipid core. Though some fibrous cap material properties have been measured, such as ultimate tensile strength and stress-strain responses, there has been very little, if any, data published regarding the fracture behavior of atherosclerotic fibrous caps. This study aims to characterize the qualitative and quantitative fracture behavior of human atherosclerotic plaque tissue obtained from carotid endarterectomy samples using two different metrics. Uniaxial tensile experiments along with miniature single edge notched tensile (MSENT) experiments were performed on strips of isolated fibrous cap. Crack tip opening displacement (CTOD) and stress in the un-cracked segment (UCS) were measured at failure in fibrous cap MSENT specimens subjected to uniaxial tensile loading. Both CTOD and the degree of crack blunting, measured as the radius of curvature of the crack tip, increased as tearing propagated through the tissue. Higher initial stress in the UCS is significantly correlated with higher collagen content and lower macrophage content in the fibrous cap (ρ=0.77, P=0.009; ρ=-0.64, P=0.047; respectively). Trends in the data show that higher CTOD is inversely related to collagen content, though the sample size in this study is insufficient to statistically substantiate this relationship. To the authors knowledge, this is the pioneering study examining the fracture behavior of fibrous caps and the first use of the CTOD metric in vascular tissue.nnnSTATEMENT OF SIGNIFICANCEnA tear in the fibrous cap of atherosclerotic plaque can lead to ischemic stroke or myocardial infarction. While there is some information in the literature regarding quantitative measures of fibrous cap failure, there is little information regarding the behavior of the tissue during failure. This study examines the failure behavior of fibrous caps both qualitatively, by examining how and where the tissue fails, and quantitatively, by measuring (a) crack tip opening displacement (CTOD) in vascular tissue for the first time and (b) uniaxial stress in the un-cracked segment (UCS). This study shows that both metrics should be evaluated when assessing plaque vulnerability.

The impact of a community-wide vascular access program on the management of graft thromboses in a dialysis population of 495 patients

BACKGROUNDnThe unpredictability of prosthetic vascular access thrombosis precludes the scheduling of elective graft thrombectomy. This results in inconsistent dialysis for patients, as well as logistical challenges for dialysis clinics and surgeons, and increased cost. In an effort to solve this problem a community-wide, prospective vascular access program (VAP) was established. This study evaluates the impact of the VAP by comparing the operative procedures and outcomes of vascular access surgery performed in the community before and after establishment of the program.nnnMETHODSnAll 17 surgeons who perform vascular access, representing five independent practice groups in Greenville, South Carolina, formed a VAP in November 1996. Dialysis patients were pooled, and all graft thrombectomies were managed on a rotational basis by a surgeon assigned daily to a specifically designated access thrombectomy operating room. The hospital records of all patients undergoing vascular access procedures from November 1, 1995, through October 31, 1996 (pre-VAP), and November 1, 1996, through October 31, 1997 (post-VAP), were reviewed.nnnRESULTSnComparison of the pre-VAP and post-VAP groups showed no significant difference in the number of patients undergoing vascular access procedures (391 versus 378), number of vascular access procedures performed (1034 versus 1,048), or average number of vascular access procedures performed per patient (2.64 versus 2.79). There was no statistical difference in the number of thrombectomies and revisions (786 versus 765; P = 0.114) or thrombectomies alone (248 versus 283; P = 0.114) in the pre-VAP and post-VAP groups. There was a significant increase in the number of procedures performed on an outpatient basis in the post-VAP group (757; 73%) compared with the pre-VAP group (575; 56%); P <0.001. There was also a significant difference in the percentage of cases performed after 6:00 PM in the pre-VAP group (262; 25%) compared with the post-VAP group (48; 4.5%; P = 0.001).nnnCONCLUSIONSnDialysis graft thrombosis, occurring in 75% of our patients annually, represents a substantial logistical dilemma necessitating the incorporation of 1,000 additional operations into a busy elective surgery schedule. An organized VAP reduces inpatient hospitalization, minimizes expensive after hours surgery, and enhances patient and physician convenience while providing a mechanism to monitor clinical outcomes and assure timely dialysis.