Evaluation of platelet activity by multiple electrode impedance aggregometry in acute coronary syndromes: pilot study in a Brazilian tertiary-care public hospital.

There is no definite recommendation for testing platelet aggregation (PA) in acute coronary syndromes (ACS) due to inconclusive evidence on the usefulness of platelet function tests to guide therapy and improve clinical outcomes. The evaluation of PA with multiple electrode impedance platelet aggregometry (MEA) may be useful to manage antiplatelet therapy and possibly influence patient outcome. The primary aim of this study was to measure PA with MEA in Brazilian patients with ACS and evaluate the association between PA and adverse clinical outcomes. Forty-seven consecutive patients admitted with ACS to a Brazilian tertiary-care public hospital were studied and PA was evaluated using MEA. Patients were followed for six months for the occurrence of all-cause death, acute myocardial infarction, or stroke. Suboptimal inhibition of PA was found in 7 patients (14.9%); 5 (10.6%) in response to ASA (acetylsalicylic acid), 2 (5.0%) to clopidogrel, and none to ticagrelor. Inadequate PA inhibition in response to ASA was significantly associated with the composite end point, but there was no significant association for insufficient PA inhibition in response to clopidogrel. This study suggested that the evaluation of PA in ACS using MEA may identify non-responders to ASA. Larger studies are necessary to define, in a public health scenario, the value of MEA in the management of ACS.

Evaluation of platelet activity by multiple electrode impedance aggregometry in acute coronary syndromes: pilot study in a Brazilian tertiary-care public hospital

There is no definite recommendation for testing platelet aggregation (PA) in acute coronary syndromes (ACS) due to inconclusive evidence on the usefulness of platelet function tests to guide therapy and improve clinical outcomes. The evaluation of PA with multiple electrode impedance platelet aggregometry (MEA) may be useful to manage antiplatelet therapy and possibly influence patient outcome. The primary aim of this study was to measure PA with MEA in Brazilian patients with ACS and evaluate the association between PA and adverse clinical outcomes. Forty-seven consecutive patients admitted with ACS to a Brazilian tertiary-care public hospital were studied and PA was evaluated using MEA. Patients were followed for six months for the occurrence of all-cause death, acute myocardial infarction, or stroke. Suboptimal inhibition of PA was found in 7 patients (14.9%); 5 (10.6%) in response to ASA (acetylsalicylic acid), 2 (5.0%) to clopidogrel, and none to ticagrelor. Inadequate PA inhibition in response to ASA was significantly associated with the composite end point, but there was no significant association for insufficient PA inhibition in response to clopidogrel. This study suggested that the evaluation of PA in ACS using MEA may identify non-responders to ASA. Larger studies are necessary to define, in a public health scenario, the value of MEA in the management of ACS.

Outcome of venous stasis ulceration when complicated by arterial occlusive disease.

OBJECTIVE: to report the outcome of patients with venous stasis ulceration (VSU) and severe arterial occlusive disease (AOD). DESIGN: retrospective study. METHODS: using the International Classification of Diseases (ICD-9), codes for VSU and AOD were cross-matched to identify patients from 1989 to 1999 at two tertiary hospitals. Entry into the study required the presence of a VSU and an ipsilateral procedure to improve AOD or major amputation during the same hospitalisation. RESULTS: fourteen patients (15 extremities) with a mean age of 80 years (range: 47-93) were identified as having VSU and AOD. Mean duration of VSU up to the time of revascularisation or amputation was 6.4 years (range: 4 months-21 years). The mean number of VSUs per extremity was 2.1 and mean wound area was 71 cm(2). Mean ankle-brachial index was 0.46 (range: 0.10-0.78). Nine extremities (60%) had a bypass procedure, 3 (20%) had an interventional procedure, 1 (0.6%) had a lumbar sympathectomy, and 2 (13%) had an amputation. Over a mean follow-up of 2.8 years, 3 extremities (23%) healed of which 2 recurred. On last review, 11 patients with 12 afflicted extremities had expired. Nine of the remaining 10 extremities were not healed at the time of death. Eight of nine bypass grafts remained patent in follow-up or at death and subsequent limb salvage was 100%. CONCLUSIONS: combined VSU and AOD represents a rare condition predominantly found in elderly patients with multiple comorbidities. Few patients had complete healing despite an arterial inflow procedure and mortality was high over the short term.

Carotid endarterectomy in women: challenging the results from ACAS and NASCET.

OBJECTIVE: To evaluate and compare the short- and long-term outcomes in female and male patients after carotid endarterectomy (CEA). SUMMARY BACKGROUND DATA: Randomized carotid trials have clearly shown the benefits of CEA in specific symptomatic and asymptomatic patients. However, the short- and long-term benefits in women appear to be less clear, and the role of CEA among women with carotid disease remains uncertain. METHODS: During a 21-year period, 1,204 CEAs were performed, 464 (39%) in women and 739 (61%) in men. Complete follow-up was available in 70% of patients. RESULTS: Women were less likely to have evidence of coronary artery disease, were more likely to be hypertensive, and had a significantly greater incidence of diabetes. The mean age at CEA was 68.5 +/- 9.5 years for women and 68.0 +/- 8.5 years for men. There were no significant differences in the use of shunts, patching, tacking sutures, or severity of carotid stenoses between men and women. Surgical death rates were nearly identical for asymptomatic and symptomatic patients. Perioperative stroke rates were similar for asymptomatic and symptomatic patients. Life-table stroke-free rates at 1, 5, and 8 years were similar for asymptomatic women and men and symptomatic women and men. Long-term survival rates at 1, 5, and 8 years were higher for asymptomatic women compared with men and for symptomatic women compared with men. As a result, stroke-free survival rates at these follow-up intervals were greater for asymptomatic women compared with men, and for symptomatic women compared to men. CONCLUSIONS: The results from this study challenge the conclusions from the Asymptomatic Carotid Endarterectomy Study and the North American Symptomatic Carotid Endarterectomy Trial regarding the benefits of CEA in women. Female gender did not adversely affect early or late survival, stroke-free, or stroke-free death rates after CEA. The authors conclude that CEA can be performed safely in women with asymptomatic and symptomatic carotid artery disease, and physicians should expect comparable benefits and outcomes in women and men undergoing CEA.

A prospective study of discharge disposition after vascular surgery.

OBJECTIVE: The purpose of this study was to determine what factors are predictive of a decline in independent living after vascular surgery during recovery. METHODS: Demographics, risk factors, operations, complications, wound status, and discharge disposition for all patients admitted to a tertiary vascular surgery service for any surgical procedure were prospectively recorded at the time of discharge. The declining order of dispositions at discharge were home (no professional assistance), home (professional assistance), rehabilitation facility, and skilled nursing facility. RESULTS: Over a 15-month period, 380 patients underwent 442 primary operations. Primary operations included 74 (17%) carotid procedures, 38 (8%) aortic procedures, 186 (42%) extremity revascularizations, 29 (7%) major amputations, 45 (10%) minor amputations, and 70 (16%) other. There were 148 (33%) complications and 85 (20%) subsequent operations (same hospitalization); 159 (36%) open wounds occurred. Forty-six percent of the patients were discharged to home (no professional assistance), 28% to home (professional assistance), 3% to a rehabilitation facility, and 18% to a skilled nursing facility; 5% died. At discharge, 51% of patients required professional assistance, 39% had a decline in disposition, and 12% went from home (+/- professional assistance) to a facility. By multivariate regression analysis, a hospital stay more than 6 days, emergency operation, open operative wound, systemic complications, and minor amputation were significantly associated (P <.001) with a decline in disposition at discharge (odds ratios: 5.5, 3.7, 3.6, 3.6, and 2.8, respectively). CONCLUSIONS: Prospective study reveals that a large proportion of patients (39%) had a decline in disposition after vascular surgery. A hospital stay more than 6 days, emergency operation, open operative wound, systemic complications, and minor amputation were strong independent predictors of decline. This information suggests modifications in treatment strategies may improve independent living status after vascular surgery and decrease the intense use of extended care resources required for this patient population during recovery.

Management of ectatic, nonaneurysmal iliac arteries during endoluminal aortic aneurysm repair.

PURPOSE: Most endografts for an endoluminal AAA repair cannot achieve an adequate hemostatic seal in ectatic common iliac arteries larger than 14 mm. The extension of the endograft into the external iliac artery can alleviate this problem but requires sacrifice of the internal iliac artery. We have used the larger diameter aortic extension cuff to obtain adequate endograft to arterial wall apposition in patients with ectatic, nonaneurysmal common iliac arteries. Because of the resultant flared configuration of the iliac limb, the technique is termed bell-bottom. However, it is unknown whether subsequent enlargement of these ectatic common iliac arteries that will lead to endoleaks or endograft migration will occur. METHODS: The records of all 96 patients who have undergone endoluminal abdominal aortic aneurysm repair at our institution were reviewed. Fourteen patients were identified in whom aortic extension cuffs were placed into 18 ectatic (>14 mm, but <20 mm) common iliac arteries. The mean follow-up time was 14 months (range, 6-24 months). The maximal diameter of the common iliac artery on computed tomography scan before endograft placement was compared with the maximal diameter at the most recent follow-up. The incidence of endoleaks, ruptures, and endograft migration related to the "bell-bottom" technique were recorded. RESULTS: The mean preoperative common iliac artery diameter was 18 mm (range, 15-20 mm). Aortic extension cuffs of 20-mm diameter and 24-mm diameter were used in 14 and 4 common iliac arteries, respectively. The diameter did not change in 11 common iliac arteries (61%), increased by 1 mm in 4 common iliac arteries (22%), and decreased by 1 mm in 3 common iliac arteries (17%). No endoleaks, ruptures, or endograft migration related to this technique was identified. CONCLUSION: The use of aortic extension cuffs for ectatic common iliac arteries expands the number of patients who can be treated endoluminally without sacrifice of the internal iliac artery. Most common iliac arteries do not increase in diameter. When enlargement occurs, the degree of dilation is minimal. Therefore, the "bell-bottom" technique appears to be an acceptable option in the management of large, nonaneurysmal iliac vessels during endoluminal abdominal aortic aneurysm repair.

Adverse consequences of internal iliac artery occlusion during endovascular repair of abdominal aortic aneurysms.

OBJECTIVE: Embolization of the internal iliac artery (IIA) may be performed during endovascular abdominal aortic aneurysm (AAA) repair if aneurysmal disease of the common iliac artery precludes graft placement proximal to the IIA orifice. The IIA may also be unintentionally occluded because of iliac trauma or coverage by the endograft. The purpose of this study was to determine the incidence, etiology, and consequences of IIA occlusion during endoluminal AAA repair. METHODS: Over 2 years, 96 patients have undergone endoluminal AAA repair. The details of the operative procedure, reasons for IIA occlusion, perioperative complications, and clinical follow-up were recorded. RESULTS: The IIA was intentionally occluded in 15 patients (16%) to treat 13 common iliac artery aneurysms, one IIA aneurysm, and one external iliac artery aneurysm. The IIA was unintentionally occluded in 9 patients (9%), resulting from traumatic iliac dissection in 5 patients and coverage of the IIA by the endograft in the remaining 4 patients. Three patients had colon ischemia. One patient with a unilateral IIA occlusion had sigmoid infarction necessitating resection. The other two patients underwent intentional occlusion of one IIA followed by unintentional occlusion of the contralateral IIA because of a traumatic iliac dissection. Both had postoperative abdominal pain and distention; rectosigmoid ischemia was revealed through colonoscopy. Conservative treatment with bowel rest and broad-spectrum antibiotics was successful in both cases. Nondisabling hip and buttock claudication occurred in seven patients (32%) at 1 month but resolved by 6 months in three of these patients. CONCLUSION: Embolization of the IIA for iliac aneurysmal disease and unintentional IIA occlusion due to trauma or graft coverage occurs in a considerable number of patients undergoing endoluminal AAA repair. Most patients with unilateral occlusion do not experience colon ischemia or disabling claudication. Therefore, unilateral embolization of the IIA is well tolerated and allows for the endoluminal treatment of patients with both an AAA and an iliac artery aneurysm, thereby expanding the number of patients who can be managed with an endovascular approach. Although acute, bilateral IIA occlusions should be avoided, significant consequences were not observed in our small series of patients.

Factors affecting the diagnosis of peripheral vascular disease before vascular surgery referral.

OBJECTIVE: Many new patients evaluated by vascular surgeons are referred by internal medicine physicians (IMPs). Objectives shared by vascular surgeons and IMPs include early identification of peripheral arterial disease (PAD), improved referral relationships, and reduction of health care costs. The approach to PAD by IMPs and identification of deficiencies that might contribute to suboptimal care form the basis for this report. METHODS: An anonymous survey was mailed to all IMPs (n = 843) in the central and southern parts of Illinois. Questions concerned IMP demographics, approach to diagnostic testing, referral patterns, perception of adequacy of education of PAD, and how often parts of the history and physical examination for PAD would be performed on the initial office visit of a hypothetical 65-year-old male with hypertension (each answer measured as 0%-25%, 25%-50%, 50%-75%, and 75%-100% of the time completed). RESULTS: There was a response from 360 IMPs: 230 IMPs (27.3%) returned the questionnaire, and 130 IMPs (15.4%) declined to participate. Practice locations for IMPs returning the questionnaire included rural (36%), suburban (22%), and urban (40%). Practice types included academic (7%), solo private (29%), group private (53%), and other (14%). A history of cardiac disease was obtained most of the time by 92% of IMPs (75%-100% answer category). Histories for pulmonary disease, diabetes mellitus, stroke, and smoking were obtained most of the time with similar frequencies (85%, 86%, 73%, and 96%, respectively). In contrast, only 37% obtained a history for claudication, and 26% obtained a history for foot ulceration 75% to 100% of the time (P <.05, all comparisons). Examination of the heart (95%) and lungs (96%) occurred most of the time (75%-100% answer category) compared with each part of the pulse examination (range, 34%-60%; P <.05, all comparisons) and aortic aneurysm palpation (39%; P <.05). If pedal pulses were absent, examination by IMPs with Doppler scan and ankle-arm indices were mostly distributed in the 0% to 25% answer category (79% and 79%, respectively). After suspecting PAD, most IMPs obtained diagnostic tests first compared with specialist referral: carotid disease (91% vs 9%), aortic aneurysm (91% vs 9%), and lower extremity PAD (86% vs 14%). Initial referral patterns were made to vascular surgeons (49%), general surgeons (33%), cardiothoracic surgeons (13%), cardiologists (4%), and radiologists (1%). Most IMPs believed medical school (70%) and residency (73%) provided adequate training for PAD diagnosis. CONCLUSIONS: Deficiencies may exist in the identification of PAD by IMPs that could adversely affect diagnosis, time to referral, health care costs, and ultimately, patient outcome. Improvements in medical school education and IMP training in the diagnosis of PAD are needed.

Clinical failure after percutaneous transluminal angioplasty of the superficial femoral and popliteal arteries.

OBJECTIVE: Anatomic patency after percutaneous transluminal angioplasty (PTA) of the superficial femoral and popliteal arteries does not guarantee clinical success. The aim of this report is to determine the causes of clinical failure after PTA. METHODS: The records of all patients who have undergone PTA of the femoropopliteal arterial segment by our vascular group were retrospectively reviewed. Only patients with complete records and at least one postprocedure clinical and anatomic assessment within the same 30-day time interval were included. Success was defined according to the Society for Vascular Surgery/International Society for Cardiovascular Surgery Ad Hoc Subcommittee on Reporting Standards for Endovascular Procedures. Anatomic cumulative patency and clinical success were calculated according to life table analysis on an intent-to-treat basis. RESULTS: We identified 85 patients who met inclusion criteria. We treated 112 lesions with an average stenosis of 80% +/- 16% and lesion length of 2.3 +/- 1.8 cm. Technical failure occurred in six (5.4%) of 112 lesions. Cumulative clinical success was 69% at 1 year, 54% at 2 years, 49% at 3 years, and 40% at 4 years. Anatomic patency was 74% at 1 year, 62% at 2 years, 57% at 3 years, and 52% at 4 years. There were 45 clinical failures; of these, twenty-seven (60%) occurred in conjunction with anatomic failure. Anatomic failure was due to restenosis in 12 patients (44%), occlusion in eight patients (30%), and restenosis with progression of disease in six patients (22%). Anatomic failure at the time of the procedure occurred in one patient (4%). Clinical failure occurred despite anatomic patency in the remaining 18 patients (40%). Etiology for clinical failure in this latter group included progression of disease within the treated vessel in 12 patients (67%), iliac disease in three patients (17%), tibial disease in two patients (11%), and bypass graft failure in one patient (5%). Fifty percent of all 45 clinical failures were successfully treated with supplemental percutaneous procedures. CONCLUSION: A PTA is an acceptable therapeutic option for the treatment of focal occlusive disease of the femoropopliteal arterial segment. Most clinical failures were due to anatomic failure, but a significant number occurred despite patency at the PTA site. Although primary clinical success rates were inferior to surgical bypass graft, supplemental PTA was possible in 50% of patients. Repeat percutaneous treatment may extend the interval of clinical success and may obviate the need for surgical bypass graft.

Special iliac artery considerations during aneurysm endografting.

BACKGROUND: The feasibility of endograft exclusion of abdominal aortic aneurysms (AAA) has been established. However, the technical challenges of graft delivery through tortuous or diseased iliac arteries and the treatment of associated iliac aneurysmal disease have received little attention. METHODS: Over 19 months, 74 patients underwent endoluminal repair of AAA and/or iliac artery aneurysms. Iliac anatomy that required special consideration during endografting was reviewed. RESULTS: Of the 74 patients, 35 (47%) had iliac anatomy that required special attention. Thirteen patients (18%) had aneurysmal involvement of a common iliac artery. Eleven of these patients required endograft extension into the external iliac artery (EIA) and hypogastric coil embolization due to the proximity of the aneurysm to the hypogastric origin. Eleven patients with ectatic, nonaneurysmal iliac arteries required aortic cuffs to achieve a distal seal in these oversized vessels. Iliac artery tortuosity or stenosis were complicating factors in 27 of the 74 patients (36%), requiring the use of brachial guidewire tension in 2 patients to facilitate tracking of the delivery device. Five patients with severely splayed aortic bifurcations required crossed placement of the iliac limbs to prevent kinking of the endograft. Occlusive atherosclerotic disease of the EIA mandated preprocedural dilatation and stenting in 3 patients and postprocedural surgical EIA reconstruction in another 5 patients. Three patients who underwent successful endograft placement required subsequent endovascular repair of traumatized EIAs. CONCLUSIONS: Iliac artery anatomy plays a significant role in the endoluminal treatment of infrarenal abdominal aortic aneurysms, complicating the procedure in up to 47% of patients with otherwise suitable anatomy. A variety of supplemental procedures, both surgical and endovascular, may be required to facilitate endograft placement. A special understanding of these constraints and proper planning is required for optimal therapy.

Algorithm for the diagnosis and treatment of endoleaks.

BACKGROUND: Endoluminal grafting of abdominal aortic aneurysms (AAA) has shown promising early results. However, endoleaks present a new and challenging obstacle to successful aneurysm exclusion. We report our experience with primary, persistent endoleaks and provide an algorithm for their diagnosis and management. METHODS: Over a 19-month period, 73 patients underwent endoluminal repair of their AAAs using a modular bifurcated endograft as part of a US FDA Investigational Device Exemption trial. Spiral computed tomography (CT) scanning was performed prior to discharge after repair to evaluate for complete aneurysm exclusion. If no endoleak was present on that initial CT scan, color-flow duplex scanning was performed at 1 month, with repeat CT scanning at 6 months and 1 year. If the initial CT scan revealed the presence of an endoleak, repeat CT scanning was performed at 2 weeks, 1 month, and 3 months, or until the endoleak resolved. Any patient with an endoleak that persisted beyond 3 months underwent angiographic evaluation to localize the source of the leak. RESULTS: At 1 month, 62 patients (85%) had successful aneurysm exclusion. The remaining 11 patients (15%) had primary endoleaks, 8 (11%) of which persisted beyond 3 months, prompting angiographic evaluation. In 2 patients the endoleak was related to a graft-graft or graft-arterial junction. One was from the endograft terminus in the common iliac artery and was successfully embolized, along with its outflow lumbar artery. The other required placement of an additional endograft component across a leaking graft-graft junction to successfully exclude the aneurysm. The remaining six endoleaks were due to collateral flow through the aneurysm sac. In 4 cases this was lumbar to lumbar flow fed by hypogastric artery collaterals to the inflow lumbar artery. In the remaining 2 patients the endoleak was found to be due to flow between a lumbar and inferior mesenteric artery. Resolution of the endoleak by coil embolization of the feeding hypogastric artery branch in 1 patient was unsuccessful due to rapid recruitment of another hypogastric branch. Two of the six collateral flow endoleaks have resolved spontaneously without treatment, while the remaining cases have been followed up without evidence of aneurysm expansion. CONCLUSION: Systematic postoperative surveillance facilitates proper diagnosis and treatment of endoleaks. This involves serial CT scans to detect the presence of endoleaks, followed by angiography to determine their etiology and guide treatment, if clinically indicated.

Feasibility of endovascular repair of abdominal aortic aneurysms with local anesthesia with intravenous sedation.

PURPOSE: Local anesthesia has been shown to reduce cardiopulmonary mortality and morbidity rates in patients who undergo selected peripheral vascular procedures. The efforts to treat abdominal aortic aneurysms (AAAs) with endovascular techniques have largely been driven by the desire to reduce the mortality and morbidity rates as compared with those associated with open aneurysm repair. Early results have indicated a modest degree of success in this goal. The purpose of this study was to investigate the feasibility of endovascular repair of AAAs with local anesthesia. METHODS: During a 14-month period, 47 patients underwent endovascular repair of infrarenal AAAs with local anesthesia that was supplemented with intravenous sedation. Anesthetic monitoring was selective on the basis of comorbidities. The patient ages ranged from 48 to 93 years (average age, 74.4 +/- 9.8 years). Of the 47 patients, 55% had significant coronary artery disease, 30% had significant chronic obstructive pulmonary disease, and 13% had diabetes. The average anesthesia grade was 3.1, with 30% of the patients having an average anesthesia grade of 4. The mean aortic aneurysm diameter was 5.77 cm (range, 4.5 to 12.0 cm). All the implanted grafts were bifurcated in design. RESULTS: Endovascular repair of the infrarenal AAA was successful for all 47 patients. One patient required the conversion to general anesthesia to facilitate the repair of an injured external iliac artery via a retroperitoneal approach. The operative mortality rate was 0. No patient had a myocardial infarction or had other cardiopulmonary complications develop in the perioperative period. The average operative time was 170 minutes, and the average blood loss was 623 mL (range, 100 to 2500 mL). The fluid requirements averaged 2491 mL. Of the 47 patients, 46 (98%) tolerated oral intake and were ambulatory within 24 hours of graft implantation. The patients were discharged from the hospital an average of 2.13 days after the procedure, with 87% of the patients discharged less than 48 hours after the graft implantation. Furthermore, at least 30% of the patients could have been discharged on the first postoperative day except for study protocol requirements for computed tomographic scanning at 48 hours. CONCLUSION: This is the first reported series that describes the use of local anesthesia for the endovascular repair of infrarenal AAAs. Our preliminary results indicate that the endovascular treatment of AAAs with local anesthesia is feasible and can be performed safely in a patient population with significant comorbidities. The significant potential advantages include decreased cardiopulmonary morbidity rates, shorter hospital stays, and lower hospital costs. A definitive evaluation of the benefits of local anesthesia will necessitate a direct comparison with other anesthetic techniques.

Long-term patency rates, complications and cost-effectiveness of polytetrafluoroethylene (PTFE) grafts for hemodialysis access: a prospective study that compares Impra versus Gore-tex grafts.

Manufacturers of polytetraflouroethylene (PTFE) grafts used for chronic hemodialysis access describe specific advantages for their respective grafts, which presumably result in greater graft patency rates, reduced complications and decreased overall costs. There are few data available in the literature to support or contradict these alleged benefits. Therefore, this prospective study was undertaken to evaluate and compare patency rates, complications and costs between two of the leading brands of PTFE that are currently being marketed for use as hemodialysis access grafts. Totals of 190 primary PTFE grafts (100 Gore-tex (W. L. Gore and Associates, Flagstaff, AZ) and 90 Impra (C. R. Bard Inc., Tempe, AZ)) were implanted in 168 consecutive patients with end-stage renal disease. A policy of non-interventions was employed for patent grafts, as no attempt was made to assist primary patency. Grafts that occluded during follow-up underwent secondary revision to maintain patency. There was no difference in primary and secondary patency by life-table analysis between Gore-tex and Impra grafts at 2 years (P > 0.53 and P > 0.13, respectively). There was also no significant difference between Gore-tex and Impra in the number of days before the first thrombectomy or in the number of thrombectomies or revisions per graft (P > O.50). Likewise, the incidence of complications was similar between the two grafts. The cost of graft implantation and maintenance of patency was not significantly different between Gore-tex and Impra grafts. It is concluded that either graft can be used for hemodialysis access with similar expected outcomes for at least 2 years following implantation.

Local anesthesia for infrainguinal arterial reconstruction.

PURPOSE: Perioperative cardiac complications occur in 4% to 6% of patients undergoing infrainguinal revascularization under general, spinal, or epidural anesthesia. The risk may be even greater in patients whose cardiac disease cannot be fully evaluated or treated before urgent limb salvage operations. Prompted by these considerations, we investigated the feasibility and results of using local anesthesia in these high-risk patients. METHODS: From January 1, 1994, through August 30, 1996, 86 infrainguinal reconstructions were performed under local infiltration anesthesia (0.5% or 1.0% lidocaine). Supplementary intravenous sedation with propofol or other agents was given as needed for patients comfort. Most patients had arterial lines but Swan Ganz catheters were used infrequently. Postoperatively, continuous electrocardiographic monitoring was continued in the intermediate or intensive care units. Patients ranged in age from 37 to 86 years (mean 68 +/- 12); 47% were diabetic, 69% had severe coronary artery disease, and 14% had end-stage renal disease. RESULTS: Operations included 7 femoral-femoral, 21 femoral-popliteal, 16 femoral-tibial and 13 popliteal-tibial bypass grafts, 9 pseudoaneurysms, and 20 distal graft revisions (+/- thrombectomy). Autogenous vein was used in eight of the femoral-popliteal and all of the femoral-tibial and popliteal-tibial bypass grafts. There were two postoperative deaths. One patient died of a stroke (1.2%) on postoperative day (POD) 2 and one died on POD 27 of unknown cause. Two other (2%) patients had nonfatal subendocardial myocardial infarctions. Conversion to general anesthesia was required in four (5%) operations, three because patients became agitated and one because a long segment of vein had to be harvested from the opposite leg. Otherwise, patients tolerated the procedures well and postanesthetic recovery problems were minimized. CONCLUSIONS: Limb salvage operations can be done under local anesthesia with acceptable complication rates. In selected patients with high-risk coronary artery disease, local anesthesia has theoretic and practical advantages and should be considered an alternative to general or regional anesthesia.

Access to the vascular system for endovascular procedures: techniques and indications for percutaneous and open arteriotomy approaches.

The ability to reliably gain access to the vascular system is fundamental to the performance of all endovascular diagnostic and therapeutic procedures. Competence with a variety of different access sites and techniques is essential if one is to be able to address the full spectrum of vascular disease and diversity of clinical circumstances. Although open surgical access is sometimes indicated, most endovascular procedures can and should be performed percutaneously, because this is the least invasive technique. Understanding the advantages, risks, and potential pitfalls of the various approaches influences the site of access chosen and whether a percutaneous or open arteriotomy technique is used. Furthermore, this knowledge permits efforts to minimize attendant risks and facilitates recognition of problems when they do occur. The net result is a procedure unspoiled by failure to gain access or avoidable access site complications.

Prevalence and distribution of calf vein thrombosis in patients with symptomatic deep venous thrombosis: a color-flow duplex study.

PURPOSE: This retrospective study was performed to identify the patterns of calf vein thrombosis in patients in whom deep vein thrombosis (DVT) was suspected and to better define the role of color-flow duplex scanning (CDS) in the evaluation of this patient population. METHODS: Over a recent 9-month period, we reviewed the vascular laboratory charts of 540 symptomatic patients (696 limbs) who underwent CDS for clinically suspected acute DVT. Patients who had a previous episode of DVT were excluded. RESULTS: CDS satisfactorily visualized all three paired calf veins in 655 of the limbs (94%). Inadequate scans (n = 41) were attributed to edema in 29, excessive calf size in eight, and anatomic inaccessibility in four. Peroneal veins were the most difficult to visualize (n = 29), followed by posterior tibial (n = 10) and anterior tibial (n = 9) veins. CDS identified acute DVT in 159 of 655 limbs (24%) that had adequate scans. Calf vein thrombi were detected in 110 of the 655 limbs (17%) and in 69% of the 159 limbs with DVT. Clots were confined to the calf veins in 53 limbs with DVT (33%). Isolated calf vein thrombi were found in 45% of outpatient limbs and in 27% of inpatient limbs with DVT. The peroneal (81%) and posterior tibial veins (69%) were more frequently involved (p < 0.001) than the anterior tibial veins (21%). In limbs with calf DVT, the prevalence of thrombosis isolated to the peroneal and posterior tibial veins was similar (37% and 25%, respectively); no limb had an isolated anterior tibial DVT (p = 0.02). CONCLUSION: CDS is a reliable method for evaluating calf veins for DVT. Calf vein thrombosis is common in patients who have acute DVT and often occurs as an isolated finding. The peroneal and posterior tibial veins are involved in the majority of cases; thrombi occur much less frequently in the anterior tibial veins. We conclude that CDS should be the noninvasive method of choice for the initial evaluation of patients in whom DVT is suspected, and we recommend that calf veins should always be studied but that routine scanning of the anterior tibial veins may not be necessary.

Determinants of success of color-flow duplex-guided compression repair of femoral pseudoaneurysms.

BACKGROUND: Ultrasonography-guided compression repair is reported to be effective therapy for femoral pseudoaneurysms that develop after catheterization procedures. This study summarizes our experience with color-flow duplex-guided repair of these lesions. METHODS: A retrospective chart review of all patients who underwent this procedure was undertaken, with statistical analysis to identify factors associated with success. RESULTS: Compression repair of 69 pseudoaneurysms was attempted. Pseudoaneurysms developed after therapeutic catheterization in 48 patients and after diagnostic procedures in 21. Sites of arterial puncture were the common femoral artery in 59 patients and the superficial femoral or profunda femoris arteries in 10. Diameters of the pseudoaneurysms ranged from 3 to 60 mm (mean, 28 mm). Compression was attempted at a mean of 5 days (range, 1 to 21 days) after catheterization. Compression produced complete thrombosis of the pseudoaneurysm at the initial attempt in 43 (62%) of 69 patients. With repeated attempts the ultimate success was 47 (68%) of 69. Success was achieved in 44 (75%) of 59 common femoral pseudoaneurysms but in only 3 (30%) of 10 superficial femoral or profunda femoris lesions (p = 0.009). Anticoagulation, sheath size, pseudoaneurysm chamber size, and time between catheterization and compression were not significantly different between lesions that were successfully compressed and those that were not. No ischemic or embolic complications were observed. CONCLUSIONS: Color-flow duplex-guided compression repair can be safely attempted as the initial therapy for all uncomplicated pseudoaneurysms arising from the common femoral artery after catheterization, with the expectation of success in most.

Prospective evaluation of new duplex criteria to identify 70% internal carotid artery stenosis.

PURPOSE: Large multicenter trials (North American Symptomatic Carotid Endarterectomy Trial, European Carotid Surgery Trial) have documented the benefits of carotid endarterectomy for treating symptomatic patients with >or=70% stenosis of the internal carotid artery. Although color-flow duplex scanning has become the preferred method for noninvasive assessment of internal carotid artery disease, no criteria have been generally accepted to identify this subset of patients. We previously reported a retrospective series to establish such criteria. This study details our results when these criteria were applied prospectively. METHODS: Carotid color-flow duplex scans were compared with arteriograms in 457 patients who underwent both studies. Criteria for >or=70% internal carotid artery stenosis were peak systolic velocity >130 cm/sec and end-diastolic velocity >100 cm/sec. Internal carotid arteries with peak systolic velocity <40 cm/sec in which only a trickle of flow could be detected were classified as preocclusive lesions (95% to 99% stenosis). Arteriographic stenosis was determined by comparing the diameter of the internal carotid artery at the site of maximal stenosis to the diameter of the normal distal internal carotid artery. RESULTS: Internal carotid artery stenosis of >or=70% was detected with a sensitivity of 87%, specificity of 97% positive predictive value of 89%, negative predictive value of 96%, and overall accuracy of 95%. Eighty-seven percent of 70% to 99% stenoses were correctly identified. False-positive errors (n=10) were attributed to contralateral internal carotid artery occlusion or high-grade (>90%) stenosis (n=5) and to interpreter error (n=1); no explanation was apparent in the other four. Eleven of 12 false-negative examinations occurred in patients with 70% to 80% internal carotid artery stenosis. CONCLUSIONS: In our laboratories, prospective application of the above velocity criteria identified internal carotid artery stenosis of >or=70% with a reasonably high degree of accuracy. Errors occurred when stenoses were borderline and in patients with severe contralateral disease. With suitably modified velocity criteria, color-flow duplex scanning remains the most reliable noninvasive method for identifying symptomatic patients who are candidates for carotid endarterectomy.

Detection of total occlusion, string sign, and preocclusive stenosis of the internal carotid artery by color-flow duplex scanning.

BACKGROUND: Stroke prevention depends on the accurate differentiation of surgically treatable preocclusive lesions from total occlusions of the internal carotid artery. This prospective study was undertaken to review the accuracy of colorflow duplex scanning for identifying carotid string signs, focal preocclusive lesions (95% to 99% stenoses), and total occlusion of the internal carotid artery. MATERIALS AND METHODS: Over an 18-month period, 4,362 patients underwent color-flow duplex scanning of the carotid arteries. Angiograms of 596 internal carotid arteries were available for comparison with the duplex scan findings. Total occlusion was diagnosed by the absence of flow in internal carotid arteries visualized on B-mode scanning. Preocclusive lesions were identified by a trickle of flow in the vessel lumen. RESULTS: Of 65 color-flow duplex scans that predicted total occlusion, 64 (98%) were confirmed by angiography. The negative predictive value for total occlusion was 99%. Twenty-six (87%) of 30 string signs and focal 95% to 99% stenoses were correctly identified. Color-flow scanning prediction of preocclusive lesions was accurate in 84% of 31 cases. Low velocities in the internal carotid artery were usually associated with a string sign, and high velocities with a focal preocclusive lesion. CONCLUSIONS: Color-flow duplex scanning accurately differentiates between stenotic and totally occluded internal carotid arteries. Identification of preocclusive lesions is not as accurate but the results are promising. Arteriographic confirmation of duplex scan findings is necessary only when scans are equivocal.