Biomedical subjects

S S Berman

Publications and source records attributed to S S Berman.

At least 19 recordsLinked to original sources

PubMed2006

Strategies for predicting and treating access induced ischemic steal syndrome.

Access induced ischemia is an uncommon but devastating complication for patients maintained on hemodialysis. A number of clinical risk factors have been identified to select patients at risk. Intraoperative measurement of the digital-brachial index may further distinguish at-risk patients when the DBI is <0.45. Once clinically significant steal has developed, surgical strategies to treat this problem should ideally reverse the ischemia while maintaining uninterrupted access for hemodialysis. To date, the distal revascularization-interval ligation or DRIL procedure has been the most consistently successful tactic in achieving these dual objectives. A number of alternative strategies have recently been proposed and will be discussed.

Arteriovenous Shunt, Surgical↗

PubMed2001

Improved patency of infrainguinal polytetrafluoroethylene bypass grafts using a distal Taylor vein patch.

OBJECTIVE: The purpose of this study was to evaluate graft patency and limb salvage rates for infrainguinal polytetrafluoroethylene (PTFE) bypass grafts using distal anastomotic Taylor vein patch in patients lacking suitable vein conduit. METHODS: We reviewed 44 patients who underwent infrainguinal bypass between January 1996 and August 2000 using 6-mm PTFE and a distal Taylor vein patch. Postoperative oral anticoagulation was administered to 80% of patients. Graft patency was confirmed during follow-up with serial graft duplex scanning. RESULTS: Operative indications were rest pain, nonhealing ulcer, or gangrene in 76% of patients, 43% of whom had undergone previous ipsilateral leg bypass. Distal anastomotic sites were the below-knee popliteal (29%) and tibial-peroneal arteries (67%). At 1 month, 1 year, and 2 years, respectively, the primary patencies (SE <10%) were 86%, 71%, and 71%; limb salvage rates were 95%, 75%, and 66%; and mortality rates were 5%, 20%, and 20%. CONCLUSIONS: These early results with PTFE and distal Taylor vein patch are promising, and markedly superior to previous reports of PTFE without anastomotic modification. Further long-term follow-up will be necessary to determine the 3- to 5-year durability of such reconstructions.

Aged↗

PubMed2001

Impact of nonpenetrating clips on intimal hyperplasia of vascular anastomoses.

Non-penetrating, arcuate-legged titanium clips create an interrupted, non-penetrated, yet compliant vascular anastomoses that is associated with significantly reduced anastomotic neointimal hyperplasia. Recent experimental and clinical studies provide evidence that the non-suture alternative changes the biology of vessel-to-vessel and graft-to-vessel connections that reduces the stimulus for hyperplasia at a number of critical points in the response to injury schema. The compliant, "blood-tight" characteristics of clipped vascular reconstructions are associated with no endothelial injury or intraluminal foreign body, minimal platelet aggregation and laminal flow. Clinical applications including vascular access, femoropopliteal bypass, and closure of carotid endarterectomies are remarkable for the absence of restenosis and preserved anastomotic patency.

Anastomosis, Surgical↗

PubMed2001

Impact of secondary procedures in autogenous arteriovenous fistula maturation and maintenance.

PURPOSE: The purpose of this study was to evaluate the impact of secondary procedures to facilitate maturation of autogenous arteriovenous (AV) fistulas and optimize their use for hemodialysis access. METHODS: The records of patients undergoing new autogenous AV fistulas were reviewed. Analyses of fistula maturation, subsequent interventions, access function, and patency were performed. RESULTS: From July 1998 through June 2000, 362 new AV access fistulas and grafts were constructed in 310 patients. In this cohort, 170 autogenous fistulas (55%) were placed in 163 patients. Fistula types included 115 antecubital brachiocephalic fistulas (Kaufmann) (68%), 47 radiocephalic fistulas (Brescia-Cimino) (28%), and 8 basilic vein transposition fistulas (4%). Secondary procedures were required in nine cases (5%) for failure to mature (4 Brescia-Cimino, 5 Kaufmann) and included 3 vein patches, 3 interposition vein grafts, 1 transposition to a more proximal artery, 1 branch ligation, and 1 balloon angioplasty of the subclavian artery; they occurred at 4.4 +/- 2.1 months (mean +/- SD). Additional procedures were needed to revise patent but failing fistulas in six cases (3.5%; 3 Brescia-Cimino, 3 Kaufmann) and included 5 transpositions to a more proximal artery and 1 vein patch; they occurred at 12.3 +/- 5.6 months (P =.002 compared with immature fistulas). For this series of autogenous fistulas, a functional access was achieved in 129 of 143 patients (90%) for whom follow-up was available. Twelve-month actuarial primary patency for autogenous fistulas was 78% compared with 49% for prosthetic grafts placed in the same period (P =.001, log-rank). CONCLUSIONS: In the current series, a 10% improvement in accomplishing or maintaining a functional autogenous access was achieved through secondary procedures applied to autogenous fistulas that either fail to mature or develop functional deterioration. Aggressive assessment of immature or failing autogenous AV fistulas for correctable lesions should be included in any hemodialysis practice to optimize their use and exploit the superiority of the native fistula.

Arteriovenous Shunt, Surgical↗

PubMed2000

Intimal growth and neovascularization in human stenotic vein grafts.

BACKGROUND: Myointimal thickening and microvessel ingrowth are commonly observed in vein graft stenosis, which complicates a third of infrainguinal bypass procedures. But a direct correlation between these two features has not been established. Our purpose was to analyze the relationship between neovascularity and intimal thickness in human vein grafts. STUDY DESIGN: Twenty-two explant stenotic vein grafts (STVG), 8 nonstenotic arterialized vein grafts (AVG), and 20 age-matched control greater saphenous veins (CGSV) were analyzed histologically and compared morphologically by light microscopy. Digitized computer image analysis was used to measure intimal thickness and quantitate microvessel ingrowth. Immunolocalization of endothelial cells around the lumen and in microvessels was determined using antibodies to factor VIII and to endothelial nitric oxide synthase (eNOS), respectively. RESULTS: Focal areas of endothelial disruption and thrombus deposition were present in 23% (5 of 22) of stenotic vein grafts. The neointima of STVG grafts was two- and fourfold thicker than that of AVG and CGSV, respectively (p < 0.0001). Microvessels were most frequently observed in the adventitia and media of STVG and increased in number with increasing intimal thickness (p < 0.001 by ANOVA). CONCLUSIONS: A fourfold increased neointimal thickness in critically stenotic vein grafts is associated with increased medial and adventitial neovascularization. Remodeling alone with doubling of the intimal thickness in nonstenotic arterialized vein grafts does not appear to be associated with enhancement of the graft microvasculature. More specific observations using an experimental model may allow us to further define the role of angiogenesis in vein graft stenosis and to determine the therapeutic implications of such observations.

Aged↗

PubMed2000

Distal revascularization-interval ligation for maintenance of dialysis access and restoration of distal perfusion in ischemic steal syndrome.

Ischemic steal syndrome after hemodialysis access challenges the clinician to reconcile the dichotomy of maintenance of access patency and restoration of distal limb perfusion. Results from traditional procedures directed toward increasing the resistance in the fistula (eg, banding, lengthening) have yielded unreliable results and frequently eventuate in fistula thrombosis. The recently described technique of distal revascularization, interval ligation (DRIL) provides a more physiological approach. Based on several recent series, application of the technique has provided excellent resolution of ischemic symptoms and superior preservation of fistula patency.

Arteriovenous Shunt, Surgical↗

PubMed1999

Comparison of carotid endarterectomy using primary closure, patch closure, and eversion techniques.

BACKGROUND: This study was undertaken to evaluate the role of eversion endarterectomy in the management of extracranial carotid occlusive disease. METHODS: A retrospective review was performed of all patients undergoing carotid endarterectomy between July 1994 and July 1998. After reviewing the records, patients were assigned to one of three groups: eversion (ECEA); open with primary closure (CEA); or open with patch closure (CEAP). Statistical comparisons were made. RESULTS: The 190 index cases comprised 33 ECEA (17%), 15 CEA (8%), and 142 CEAP (75%). Both ECEA and CEA were more likely to be done on males versus females compared with CEAP (P = 0.01). For the entire 190 cases, stroke occurred in 1 patient (0.5%); and myocardial infarction in 2 patients (1%), resulting in death in both. Two patients (1.4%) in the CEAP group have undergone redo surgery at 8 and 24 months. CONCLUSIONS: This study demonstrates that eversion endarterectomy achieves early results similar to open endarterectomy with and without patch closure.

Carotid Artery, Common↗

PubMed1999

Anastomotic tissue response associated with expanded polytetrafluoroethylene access grafts constructed by using nonpenetrating clips.

PURPOSE: The gross, light microscopic, and scanning microscopic appearance of arterial and venous anastomoses in expanded polytetrafluoroethylene (ePTFE) access grafts constructed with nonpenetrating clips were compared with that of those constructed with polypropylene suture. We hypothesized that clip-constructed anastomoses would provide controlled approximation of native vessel intimal and medial components with the ePTFE grafts. We further hypothesized that anastomotic healing with clips would involve primarily an intimal cellular response, as compared with suture-constructed anastomoses in which cells within the media and adventitia walls participate. METHODS: Femoral artery to femoral vein arteriovenous (AV) grafts were constructed in five dogs using 4-mm internal diameter ePTFE graft material. Each animal received one AV graft with anastomoses constructed by using polypropylene sutures in one leg and one AV graft with anastomoses constructed with Vascular Closure System clips in the contralateral leg. Animals were given aspirin for the duration of the study, and grafts were explanted at 5 weeks. At the time of explantation, graft segments were grossly evaluated and then underwent light and scanning electron microscopic analysis. RESULTS: At the time of explantation, all access grafts were patent. Joining the ePTFE grafts to the native vessels with clips resulted in minimal vessel wall damage. The lumenal contours of the discontinuous approximation were smooth and without gross endothelial disruption. These observations are in contrast to the lumenal compromise and endothelial disturbance associated with the sutured anastomoses. Furthermore, hemostasis was achieved immediately in the clipped grafts, decreasing the incidence of perianastomic hematoma. Finally, cellular reconstitution occurred at the anastomotic cleft in both the sutured and the clipped junctions. The neointima exhibited an endothelial cell lining on the lumenal surface and the presence of alpha-smooth muscle cell actin positive cells within the subendothelial layer. CONCLUSION: Vascular Closure System clips are a viable alternative to suture for the approximation of ePTFE AV access grafts to native blood vessels. The use of the clips resulted in a more streamlined anastomosis, with decreased vessel wall damage, immediate hemostasis, and a trend toward shorter procedure times.

Animals↗

PubMed1999

Characterization of cellular density and determination of neointimal extracellular matrix constituents in human lower extremity vein graft stenoses.

UNLABELLED: Arterial restenosis has been attributed to a hyperproliferative smooth muscle cell response. Paradoxically, studies of human coronary atherectomy and vein graft stenotic lesions have demonstrated a relatively low nuclear proliferative rate with the majority of the neointimal mass consisting of extracellular matrix. The purpose of the present study was to characterize the cellular density and determine the relative composition of the extracellular matrix protein constituents in stenotic, human lower extremity vein-bypass graft lesions. METHODS: Duplex surveillance of 148 consecutive infrainguinal bypass grafts identified 17 patients with 22 preocclusive autogenous vein graft stenoses (mean graft age 7 months). Morphological analyses of these stenotic lesions were compared with excised samples of 20 greater saphenous vein segments taken at the time of graft implantation from matched control patients. Intimal and medial areas were compared and cell density was determined with fluorescent nuclear (Bisbenzimide) staining. Differential light microscopy with pentachrome staining was performed to determine the relative percent composition of intimal matrix constituents by stereological morphometric (point-count) techniques. RESULTS: The intimal areas for control and stenotic vein segments were 1.64 x 10(6) microm2 and 3.85 x 10(6) microm2, P < 0.0001, whereas the intimal nuclear densities (cells/unit volume) were 1.42 x 10(3) and 1.70 x 10(3) cells/microm2, P = 0.03. respectively. The corresponding medial area and medial nuclear densities were 5.01 x 10(6) microm2, 3.31 x 10(6) microm2; P = 0.08, and 2.27 x 10(3), 3.29 x 10(3); P = 0.001, for control and stenotic specimens, respectively. The intima:media area ratios were much greater, whereas the intimal and medial cell densities were only slightly greater in the stenotic compared with control veins. The relative composition of intimal extracellular matrix proteins of stenotic vein graft segments consisted of 21% cellular (fibrous) material, 33% collagen, and 46% glycosaminoglycan ground substance. CONCLUSION: The intimal lesions responsible for lower extremity vein graft stenosis are more hypertrophic than hyperplastic. Therapies aimed at preventing arterial and vein graft restenosis may thus need to inhibit matrix biosynthetic processes in addition to cellular proliferation.

Aged↗

PubMed1998

Healing response associated with balloon-dilated ePTFE.

Deployment of endovascular grafts composed of a metallic stent surrounded by expanded polytetrafluoroethylene (ePTFE) stretches the polymer beyond its original dimensions, altering the structural characteristics of the ePTFE. We hypothesized this structural modification would alter the healing response associated with the implant. In this study, 4 mm i.d. of ePTFE (30 microns internodal distance) vascular grafts were balloon dilated using angioplasty balloons having final diameters of 6 (1.5X), 8 (2X), 10 (2.5X), 12 (3X), and 18 (4.5X) mm. Following balloon dilatation of the ePTFE, a circular punch (6 mm in diameter) was used to prepare polymer samples for implantation. The ePTFE circular patches were implanted within subcutaneous tissue and epididymal fat pads of male Sprague-Dawley rats. After 5 weeks, the implants were removed and analyzed for fibrous capsule formation, inflammation, and neovascularization associated with the material. Histological analysis revealed the formation of fibrous capsules only with control subcutaneous implants. The inflammatory response associated with subcutaneously implanted ePTFE was decreased significantly following balloon dilatation to at least 2.5 times the original diameter of the graft. In contrast, ePTFE implanted within adipose tissue demonstrated a significantly greater inflammatory response following balloon dilatation when compared to control implants. Only ePTFE balloons dilated to 6 mm and implanted within adipose tissue demonstrated neovascularization to any extent. These data suggest the structural modifications incurred by ePTFE following balloon dilatation dramatically affect the inflammatory response associated with an implant. Therefore, polymeric materials used for endovascular graft technology require designs that consider changes in polymer healing inherent to device design.

Adipose Tissue↗

PubMed1998

A regional pedal ischemia scoring system for decision analysis in patients with heel ulceration.

PURPOSE: The objective of this study was to evaluate patients undergoing operative debridement for heel ulceration and to categorize pedal perfusion and its influence on therapeutic alternatives. METHODS: Patients with heel ulceration were stratified by arteriography and graded I (patent posterior tibial, PT), II (occluded PT/reconstituted from peroneal), III (PT reconstituted from dorsal pedal), IV (no PT reconstitution but visible heel tributaries), and V (avascular heel). RESULTS: From May 1992 through January 1997, 23 patients underwent operative treatment for 25 heel ulcers. The heel ischemia score stratified patients into two groups: 1, revascularization/debridement (71% grades I to III, 29% grade IV, 0% grade V); and 2, free tissue transfer with or without revascularization (100% grades IV, V). Cumulative functional limb salvage was 91% (BP), 60% (BP + TT), and 81% (TT) at 24 months (P = 0.15 log rank). CONCLUSION: The heel ischemia score may direct treatment of heel ulceration by identifying patients who will need vascularized tissue transfer early in their treatment regimen.

Angiography↗

PubMed1998

Vein patching reduces neointimal thickening associated with prosthetic graft implantation.

PURPOSE: Modified anastomotic techniques utilizing autogenous vein-cuffs or patches have been devised with the hope of improving prosthetic graft patency. The mechanisms of the presumed improvement in patched anastomoses have never been elucidated and remain speculative. We characterized the healing response of the Taylor vein patch in prosthetic arteriovenous fistulae in a canine model of intimal hyperplasia. METHODS: Six adult dogs underwent placement of bilateral (6 patched, 6 control) 4-mm diameter expanded polytetrafluoroethylene loop femoral artery-vein fistulae. Serial duplex ultrasound examinations confirmed graft patency until explant at 6 weeks. Differential light microscopy with computerized image analysis was performed on serial 5-microm sections. Intimal thickness through the venous anastomosis and outflow veins of Taylor patch and control (nonpatched) grafts were compared. Cell type-specific immunocytochemical antibody stains for smooth muscle cells (alpha SMC actin) and endothelial cells (von Willebrand factor) were performed. RESULTS: Eleven of 12 grafts remained patent for 6 weeks, 1 control graft thrombosed. Mean duplex-derived peak systolic velocities of patched (96 cm/sec) and control (108 cm/sec) grafts were similar. Microscopy revealed more intimal pannus anastomotic suture line ingrowth in controls (mean thickness = 178 microm) than Taylor patched grafts (mean 147 microm, p = 0.0002). Significantly less intimal thickening was present in the outflow vein of patched (mean thickness = 90 microm) versus control grafts (mean 195 microm, P <0.0001). The intima maintained a single cell layer of vWF + endothelial cells, while the majority of the cells comprising the lesion expressed alpha SMC actin. CONCLUSION: Perianastomotic pannus is primarily composed of intimal smooth muscle cells. Neointimal thickening is significantly reduced in prosthetic arteriovenous fistulae created with the Taylor vein patch in a canine model. Reduction in perianastomotic intimal thickening may explain the reported clinical improvement in prosthetic bypass graft patency when modified with vein patch techniques.

Anastomosis, Surgical↗

PubMed1998

Treatment of patients with venous thromboembolism and malignant disease: should vena cava filter placement be routine?

PURPOSE: It has been proposed that inferior vena cava filter placement should be the initial treatment of deep venous thrombosis (DVT) or pulmonary embolus (PE) in patients with coexisting malignant disease. We have chosen instead to selectively place filters only in patients with either a contraindication to anticoagulation therapy or a subsequent complication from anticoagulation therapy. The treatment efficacy and mortality rates in patients with concomitant malignant disease and venous thromboembolism using this approach was determined. METHODS: We retrospectively reviewed all patients at our institution with malignant disease in whom venous thromboembolism developed between August 1991 through August 1996 and identified 166 patients with PE (n = 8), DVT (n = 147), and DVT/PE (n = 11). Of these patients, 138 (83.1%) were initially treated with anticoagulation therapy, and 28 (16.9%) had primary filter placement because of contraindications to anticoagulation therapy (10 for intracranial tumors, 11 for recent or upcoming operations, 6 for recent hemorrhage, and 1 for a malignant bloody pericardial effusion). RESULTS: Thirty-two (23%) of the 138 patients who initially underwent anticoagulation therapy subsequently required a filter for the following reasons: bleeding (n = 15, 10.9%); recurrent thromboembolism (n = 6, 4.3%); heparin-induced thrombocytopenia (n = 1, 0.7%); and perceived high risk for bleeding with continued anticoagulation therapy (n = 11, 8%). Both bleeding and recurrent thromboembolism developed in 1 patient. Sixty patients (36%) received filters. No major technical complications occurred from filter placement. Major recurrent thromboembolic complications developed in 10 patients: DVT (n = 6, 10%), PE (n = 2, 3.3%), inferior vena cava thrombosis and phlegmasia cerulea dolens (n = 1, 1.7%), superior vena cava thrombosis (n = 1, 1.7%). Venous gangrene developed in 1 patient with DVT. The 1-year actuarial survival rates for patients treated with filter and anticoagulation therapy were 35% and 38%, respectively (P = NS). CONCLUSION: In summary, our experience suggests that 64% of patients with malignant disease and venous thromboembolism are effectively treated with anticoagulation alone; 17% require primary filter placement for standard indications, and an additional 19% require subsequent filter placement because of complications (primarily bleeding) or failure of anticoagulation therapy. Although technical complications of filter placement are low, serious life-threatening or limb-threatening thromboembolic complications developed in 17% of patients. Survival was poor in all patients, regardless of treatment. These data support a conservative approach of routine anticoagulation therapy with selective filter placement.

Adolescent↗

PubMed1997

Effects of balloon dilatation on ePTFE structural characteristics.

The search for less invasive treatments for cardiovascular disease has lead to the development of endovascular stent grafts, metallic and alloy stents surrounded by prosthetic vascular graft material. Introduced intravascularly, the deployment of stent grafts requires balloon dilatation of the device which results in expansion of the stent along with the vascular graft material. We hypothesized that balloon dilatation of stent grafts would alter the physical structure of the prosthetic graft material. In this study, noncompliant angioplasty balloons were used to dilate expanded polytetrafluoroethylene (ePTFE), a material commonly used for endovascular stent-graft technology. The maximal outer diameter (inflated balloon within the lumen) and the recoiled outer diameter (balloon removed) of two types of ePTFE, 3-mm inside diameter (i.d.) thin wall (30-micron internodal distance) and 4-mm i.d. standard wall (30-micron internodal distance), were measured to compare material recoil. Following balloon dilatation, ePTFE samples were prepared for scanning electron microscopic examination and the following parameters were measured: wall thickness, internodal distance, nodal width, interfiber distance, and fiber width. Following primary dilatation, both types of ePTFE recoiled approximately 20% regardless of inflated balloon diameter. However, following eight repetitive balloon dilatations, recoil decreased to approximately 10%. Scanning electron microscopic analysis revealed variations in internodal distance and significant decreases in wall thickness, nodal thickness, and interfiber distance. Fiber width was significantly decreased following dilatation of 3 mm, but not 4 mm ePTFE. Our data support our initial hypothesis that balloon dilatation alters the structure of ePTFE.

Blood Vessel Prosthesis↗

PubMed1997

Differential healing and neovascularization of ePTFE implants in subcutaneous versus adipose tissue.

The preclinical evaluation of polymer biocompatibility is often performed using animal subcutaneous implant models. The choice of subcutaneous tissue as the implant site is due to a number of factors including simplicity of the surgery involved. Results from subcutaneous implants cannot necessarily be extrapolated to other tissues due to the differences in cellular composition of tissues. We have evaluated and compared the healing characteristics of expanded polytetrafluoroethylene (ePTFE) discs implanted in either subcutaneous tissue or epididymal fat pad tissue in rats. Following 3 and 5 weeks of implantation, the healing characteristics of discs were evaluated histologically with particular emphasis on tissue and polymer neovascularization. Implants placed in subcutaneous tissue exhibited limited formation of new microvascular elements within and directly in contact with the polymer, and the formation of an extensive fibrous capsule. In contrast, ePTFE implanted in the epididymal fat pads of rats exhibited extensive neovascularization of tissue surrounding the polymer, penetration of these microvascular cells into the graft interstices for distances < or = 100 microns and no morphological evidence of a fibrous capsule. The rat epididymal fat pad provides an alternative tissue for polymer healing evaluations. Due to the extensive presence of fat in subcutaneous tissue in humans, we suggest the fat pad model provides a more relevant preclinical evaluation of the healing characteristics of polymers used clinically in anatomic positions which contain significant amounts of fat.

Adipose Tissue↗

PubMed1997

The effects of porosity on endothelialization of ePTFE implanted in subcutaneous and adipose tissue.

Healing of biomaterial implants varies depending on the type and structure of material and the tissue surrounding the implant. In this study we examined structural differences of 30 microm, 60 microm, and 100 microm expanded polytetrafluoroethylene (ePTFE) using scanning electron microscopy, and we also investigated differences in healing for these three different porosity ePTFE grafts implanted within subcutaneous tissue and adipose tissue. Scanning electron microscopic examination of 30 microm, 60 microm, and 100 microm ePTFE revealed structural differences and differences in fiber density within the internodal space. Circular patches (6 mm in diameter) of 30 microm ePTFE were implanted within subcutaneous tissue and epididymal fat pads of male Sprague-Dawley rats. After 5 weeks, the implants were removed and analyzed for fibrous capsule formation, endothelialization, and for activated monocytes and macrophages in association with the material. Histological evaluation revealed dense fibrous capsule formation surrounding only the 30 microm ePTFE subcutaneous implants. From immunohistochemistry data obtained, we generated an Endothelialization Index (measure of neovascularization) and a Monocyte/Macrophage Index (measure of inflammatory response) for each sample. Consistently, 60 microm ePTFE had the greatest Endothelialization Index at both implant sites while 100 microm ePTFE generally had the largest values for the Monocyte/Macrophage Index. These data indicate that both the structure of the material and the site of implant influence the healing characteristics of ePTFE and suggest that activated monocytes and/or macrophages associated with the implant may inhibit endothelialization of ePTFE.

Adipose Tissue↗

PubMed1997

The influence of routine completion arteriography on outcome following carotid endarterectomy.

The necessity for routine completion arteriography (RCA) following carotid endarterectomy (CEA) is controversial, with the reported yield of clinically significant findings varying from 3% to 16%. In order to determine the utility of RCA, we reviewed completion studies in 154 consecutive CEAs, defined the frequency and characteristics of arteriographic defects, and correlated RCA defects with early outcome (internal carotid artery [ICA] occlusion, stroke) and late restenosis. All intraoperative RCAs were reviewed by two blinded observers and categorized into three subsets: Group A (n = 69) normal; Group B (n = 29), abnormal, severe defects; Group C (n = 56), abnormal, mild-moderate defect. RCA detected 32 defects in Group B: 10 internal carotid (ICA), seven endpoint flaps, two kinks, one dissection; 16 external carotid (ECA), 10 severe endpoint defects and six total occlusion; six common carotid (CCA), five irregular proximal shelfs, one web. Thirty of 32 defects were successfully repaired as confirmed by normal repeat RCA studies; one ECA defect was not repaired and the ICA dissection was irreparable. In Group C, 67 mild-moderate defects were identified, but not corrected. These included < 30% stenosis in the ICA (12), ECA (18), CCA (24), and vein patch corrugation or irregularity (13). For the entire series the postoperative ICA occlusion rate was 2% (3/154), stroke rate 2.6% (4/154), and a subsequent > 50% restenosis rate of 7% (11/154). The yield from routine carotid completion arteriograms was significant, with 19% of studies identifying a severe defect that required repair. Although the difference in stroke rates and restenosis between the different groups did not reach statistical significance, patients with normal intraoperative arteriograms initially or after correction of a significant RCA defect had no early carotid occlusion (p = 0.05, Fisher's exact test) compared to patients with residual RCA defects. All early carotid occlusions occurred in patients with unrepaired defects. We conclude that RCA is an important method of quality control after CEA and exerts a subtle, but real, reduction in postoperative complications.

Aged↗

PubMed1997

Prospective validation of threshold criteria for intervention in infrainguinal vein grafts undergoing duplex surveillance.

Although color flow duplex surveillance (CFDS) of infrainguinal vein grafts has gained wide acceptance, definitive criteria mandating graft revision remain to be established. We prospectively evaluated 101 infrainguinal vein grafts undergoing CFDS in order to validate threshold duplex criteria for intervention which were derived from our previous experience and that reported by others. Complete CFDS of the bypass conduit and adjacent inflow and outflow arteries and Doppler-derived ankle brachial indices (ABI) were obtained every 3 months x 4 and every 6 months thereafter. The following threshold criteria mandating further evaluation and intervention to prevent graft occlusion were applied: high-velocity criteria (HVC) defined as peak systolic velocity (PSV) > 300 cm/sec and velocity ratio (Vr) > 3.5; low-velocity criteria (LVC) defined as PSV < 45 cm/sec; an ABI decrease > 0.15. Fifty-one grafts had normal serial CFDS and ABI; none subsequently occluded or required revision. Stenosis was detected by CFDS in 43 grafts (PSV > 180 cm/sec, Vr > 1.5). Within this subgroup, 54% of grafts subsequently required revision (20/43) or occluded (3/43). All grafts in this subgroup with stenoses progressed to PSV > 300 or Vr > 3.5 prior to revision or occlusion. Ten lesions (23%) regressed spontaneously without intervention (mean PSV 252 cm/sec, mean Vr 3.2); 10 lesions (23%) are stable, non-progressive, and remain under surveillance. Two grafts were abnormal by LVC; one was successfully revised, the other occluded prior to intervention. Five grafts had normal CFDS and ABI decrease > 0.15. Four were revised (three inflow lesions, one outflow lesion) and one occluded (missed lesion by CFDS). Only five graft occlusions occurred in the entire series: three grafts met HVC and occluded prior to intervention; one developed an ABI drop of 0.4 due to graft stenosis missed by CFDS and uncovered following thrombolysis, and the other graft met LVC and occluded prior to intervention. Infrainguinal vein grafts with normal serial CFDS and ABI are at minimal risk of spontaneous graft occlusion. When CFDS is abnormal (PSV > 180 cm/sec, Vr > 1.5), over 50% of grafts will ultimately require revision or progress to occlusion. Grafts with such lesions can be safely monitored by CFDS until progression to lesions meeting HVC occurs with minimal risk of graft occlusion. A decrease in ABI > 0.15 with normal CFDS mandates arteriography to identify inflow and outflow lesions or a missed graft stenosis. The present study prospectively validates threshold intervention criteria for graft lesions meeting HVC (PSV > 300 cm/sec, Vr > 3.5), LVC (PSV < 45 cm/sec throughout graft) or an ABI decrease > 0.15.

Aged↗