Hyperbaric oxygen decreases intimal thickness and area after carotid artery balloon injury in a rat model.

BACKGROUND: Clinical studies have suggested a benefit for hyperbaric oxygen (HBO) treatment in decreasing symptomatic restenosis after coronary angioplasty. We hypothesize that HBO treatment will decrease hyperplastic intimal area after arterial balloon injury in a rat. METHODS: Fifty-four male Sprague-Dawley rats (Charles River Laboratories, Wilmington, MA) were randomly assigned either to room air (n = 27) or a treatment group (n = 27) receiving HBO treatment (2 hyperbaric treatments of 100% oxygen at 2 bars for 90 min). A 2F balloon-tipped catheter was used to injure the right common carotid arteries, which were harvested at 7, 14, and 28 days. Postinjury intimal thickness and area were measured from hematoxylin-eosin-stained specimens at each time point. Computer-assisted histomorphometry was used to calculate maximal intimal thickness, relative intimal thickness (ratio of intimal to intimal plus medial thickness), intimal area, and the intimal to medial area ratio. RESULTS: There was a 42.3% reduction in maximal intimal thickness (P = 0.0012) and a 36.5% reduction in intimal area (P = 0.0337) at day 28 in the HBO-treated group (mean ± standard error [SE], 0.0425 ± 0.0054 mm for maximal thickness and 0.065 ± 0.0056 mm(2) for area) when compared to the normoxic group (0.0737 ± 0.004 mm for maximal thickness and 0.0413 ± 0.0074 mm(2) for area). The relative intimal thickness also showed a 28.3% reduction at day 28 in the HBO-treated group (ratio of 0.38 ± 0.0329) compared to the normoxic group (ratio of 0.53 ± 0.0141; P = 0.0065). CONCLUSIONS: Our results indicate that HBO treatment decreases maximal intimal thickness and intimal area of the carotid artery after balloon injury. This could have significant clinical implications on the increasing number of endovascular interventions in vascular surgery and cardiology.

Platelet function after cessation of chronic clopidogrel therapy.

Surgeons increasingly encounter patients on clopidogrel therapy who are preparing to undergo surgery. The goal of this study was to examine the change in platelet function after the common clinical scenario of discontinuing chronic clopidogrel therapy in those patients preparing to undergo an elective surgery, and the time course of platelet function recovery after clopidogrel discontinuation. Patients on clopidogrel therapy scheduled for an elective surgical procedure had their platelet function tested using a VerifyNow P2Y12 device (Accumetrics, San Diego, CA). Platelet inhibition was evaluated at baseline before clopidogrel discontinuation, and subsequently studied every other day in the week before their scheduled procedure. Mean platelet inhibition was 32.1 per cent on Day 0 (before clopidogrel discontinuation), decreasing to 3.7 per cent on Day 4. Platelet inhibition decreased significantly after discontinuation of clopidogrel in a time-dependent manner (P = 0.011), although a considerable interindividual variability of P2Y12 reaction units values was observed over the study period. Patients on concomitant proton pump inhibitors and clopidogrel demonstrated a decreased effect of clopidogrel. In conclusion, individual platelet function monitoring may assist the surgeon in perioperative decision-making in patients receiving clopidogrel therapy preparing to undergo elective surgery.

Accelerating the pace of surgical quality improvement: the power of hospital collaboration.

HYPOTHESIS: A regional collaborative approach is an efficient platform for surgical quality improvement. DESIGN: Retrospective cohort study. SETTING: Academic research. PATIENTS: Patients undergoing general and vascular surgical procedures in 16 hospitals of the Michigan Surgical Quality Collaborative (MSQC) were evaluated quarterly to discuss surgical quality, to identify best practices, and to assess problems with process implementation. MAIN OUTCOME MEASURES: Results among MSQC patients were compared with those among 126 non-Michigan hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) over the same interval. RESULTS: A total of 315 699 patients were included in the analysis. To assess improvement, patients were stratified into 2 periods (T1 and T2). The 35 422 MSQC patients (10.7% morbidity in T1 vs 9.7% in T2 [9.0% reduction], P = .002) showed improvement, while 280 277 non-Michigan ACS NSQIP patients did not (12.4% morbidity in T1 and T2, P = .49). No improvements in mortality rates were noted in either group. Overall, the odds of experiencing a complication in T2 compared with T1 were significantly less in the MSQC group (odds ratio, 0.898) than in the non-Michigan ACS NSQIP group (odds ratio, 1.000) (P=.004). CONCLUSION: A statewide surgical quality improvement collaborative supported by a third-party payer showed significant improvement in quality and high levels of participant satisfaction.

Clostridium septicum aortitis: Report of two cases and review of the literature.

Clostridium septicum aortitis is a rare infection that has a strong association with occult colonic malignancy. To our knowledge, we report the 25th and 26th cases of C septicum aortitis in the English literature and make recommendations for its management. The first patient was a 75-year-old man who presented with abdominal pain. Computed tomography showed the presence of periaortic gas. He underwent aortic débridement and extra-anatomic bypass after blood cultures revealed C septicum. Four months after the initial presentation, he was readmitted with lethargy, found to have recurrent periaortic gas, and died. The second patient was a 76-year-old woman who presented with a 5-cm abdominal aortic aneurysm with surrounding retroperitoneal gas. She underwent emergency aortic ligation and retroperitoneal débridement. Her blood and intraoperative tissue cultures also grew C septicum. She had a prolonged postoperative course and ultimately died on hospital day 94. Both patients were found to have concurrent colon adenocarcinomas. C septicum aortitis is a lethal disease that necessitates prompt surgical intervention and appropriate antibiotic therapy. The strong association of C septicum with occult malignancy should prompt the astute clinician to undertake an exhaustive search for a neoplastic process.

Open vs. endovascular repair of isolated iliac artery aneurysms: A 12-year experience.

OBJECTIVE: To examine contemporary operative techniques and outcomes for repair of isolated iliac artery aneurysms. METHODS: We retrospectively reviewed the charts of all patients who underwent repair of an isolated iliac artery aneurysm from February 1995 to June 2007. Mycotic aneurysms and patients with concurrent infrarenal abdominal aortic aneurysms greater than 3.5 cm in diameter were excluded from analysis. Patients with prior abdominal aortic aneurysm repair were not excluded. RESULTS: Fifty-six patients (96% male; mean age, 72 +/- 10 years) had either open (n = 24) or endovascular (n = 32) repair with median follow-up of 36 months. Seven patients were treated for rupture, six with open repair, and one with an endograft. Average aneurysm size for patients in the open and endovascular repair cohorts was 4.5 +/- 2.4 cm and 4.0 +/- 1.1 cm, respectively (P = .35). One episode of endograft limb thrombosis at five months was treated with catheter-directed thrombolytic therapy and stent placement. Thirty-day mortality for patients undergoing elective and emergent open repair was 1/18 (6%) and 1/6 (17%), respectively. There was no 30-day mortality for the endovascular group. Median length of stay was 10.5 days in the open group and one day in the endovascular elective group (P < .01). There was no mid-term aneurysm-related mortality in either group. Primary patency rates were similar between the open and endovascular groups at five years (100% vs. 96%, P = .07). Aneurysm sac diameter decreased in 67% (21/28) of patients that underwent endovascular repair. One patient with a Type III endoleak required relining of the endograft with a second endograft at 72 months. CONCLUSION: These data demonstrate that in appropriately selected patients, endovascular repair of isolated iliac artery aneurysms is a safe, effective alternative to open repair with mid-term follow-up. Endovascular repair is associated with a significantly reduced hospital length of stay and may be associated with decreased need for transfusion and mortality when compared with open repair.

Low-fidelity exercises for basic surgical skills training and assessment.

BACKGROUND: The goal of this study was to develop and validate low-fidelity exercises for basic surgical skills training and assessment. METHODS: Five low-fidelity exercises were developed and administered to 40 participants. Participants were classified as novice or proficient based on level of training. Objective metrics were used for scoring. The cost for assembling 1 complete set of 5 exercises and all necessary supplies for practice and evaluation was $150. Once this set was assembled, the subsequent cost for replacement material was $5/participant examined. RESULTS: Twenty-four participants were categorized as novice and 16 as proficient. Proficient participants scored significantly higher than novice participants (P <.05) for exercises assessing needle-driving skills, 2-hand coordination, and knot tying, thus establishing construct validity. Cronbach's alpha coefficient for internal consistency was .78, which demonstrates the exercises' reliability as a testing instrument. CONCLUSIONS: These data provide preliminary evidence of construct validity and internal consistency for a cost-effective series of low-fidelity basic surgical skills exercises.

Acute abdominal vascular emergencies.

Abdominal vascular emergencies are relatively uncommon, frequently catastrophic, and highly lethal. Despite improved understanding of the pathophysiology and natural history of these disorders, delays in diagnosis and treatment remain the most important factors contributing to the observed high mortality. A high index of clinical suspicion together with a sound understanding of the clinical presentation, natural history, and management of these disorders are critical to improving outcomes. This article focuses on abdominal vascular emergencies presenting with acute visceral ischemia or catastrophic intra-abdominal hemorrhage.

Vascular endothelial growth factor-165 gene therapy promotes cardiomyogenesis in reperfused myocardial infarction.

BACKGROUND: Vascular endothelial growth factor (VEGF)-165 promotes cardiomyogenesis in chronic myocardial ischemia and nonreperfused myocardial infarction (MI). It is unknown whether this effect is present in reperfused MI. We sought to investigate the effect of VEGF-165 gene therapy on cardiomyogenesis after reperfused MI. METHODS AND RESULTS: Twenty-four Yucatan minipigs underwent thoracotomy and a vascular clamp was placed in the left circumflex artery. Reperfusion was reestablished after 90 minutes, and VEGF-165 gene therapy or placebo was administered. A replication-deficient recombinant human adenovirus serotype 5 was used for gene transfer (Ad5-VEGF165). The same viral vector devoid of VEGF gene (Ad5-beta-galactosidase) was used as placebo. Two administration routes were tested, intramyocardial (IM) injection and circumflex intracoronary (IC) infusion. The pigs were assigned to one of the following groups: IM Ad5-VEGF165 (n = 6), IM Ad5-betaGal (n = 6), IC Ad5-VEGF165 (n = 6), and IC Ad5-betaGal (n = 6). All pigs received 5-bromo-2'-deoxyuridine (BrdU) 250 mg IV twice a week to label cells undergoing DNA replication. The hearts were explanted at 4 weeks. BrdU-labeled cardiomyocytes in the peri-infarct area were counted by a pathologist blinded to group assignment. The number of BrdU-labeled cardiomyocytes per million cells was 4-fold higher in the group receiving IM VEGF-165 (64 +/- 11.4) vs. IM placebo (16 +/- 10.6), P = 0.034. No difference in infarct size or ventricular function was observed between the groups. CONCLUSIONS: IM VEGF-165 gene therapy promotes cardiomyogenesis in reperfused MI. However, no benefit in infarct size or cardiac function was observed at 4 weeks. The origin of these cells remains unknown and needs to be determined.

Factors affecting the severity of spontaneous retroperitoneal hemorrhage in anticoagulated patients.

BACKGROUND: Clinical manifestations of spontaneous retroperitoneal hemorrhage (SRH) range from a small decrease in hemoglobin to hypotension requiring transfer to the intensive care unit (ICU). Our goal was to identify which anticoagulated patients are at increased risk for SRH and its complications. METHODS: We conducted a retrospective review of 180 patients with SRH. Age, sex, presence of comorbidities, hemoglobin decrease, transfusion requirement, ICU stay, and length of ICU stay were recorded. Patients were divided into 5 groups based on their anticoagulants: (1) heparin and Coumadin, (2) heparin only, (3) Coumadin only, (4) heparin +/- Coumadin and aspirin (ASA) +/- Plavix, and (5) other anticoagulants. RESULTS: Group 4 patients were more likely to require ICU admission and have longer ICU stay compared to others (P = .021 & P < or = 0.0001, respectively, by Kruskall-Wallis test). Patients with coronary artery disease were more likely to require ICU admission (P = .01 by chi-square test). CONCLUSIONS: Patients on combined anticoagulant-antiplatelet therapy are more likely to require ICU admission and longer ICU stay. Close observation is warranted in these patients for early detection of SRH.

Changes in inferior vena cava filter placement over the past decade at a large community-based academic health center.

OBJECTIVE: A significant increase in the frequency of inferior vena cava (IVC) filter placement at our large community-based academic health center led us to evaluate changes in indications, devices, and providers over the past decade. METHODS: A single-center retrospective review of all filter placements was performed comparing 76 patients in 1995 with 470 patients in 2005. Demographic data, provider data, filter type, and indications for placement were tabulated. Complications, follow-up evaluation, filter removal, and patient outcomes were examined. RESULTS: There was a greater than sixfold increase in the number of filters placed in 2005 vs 1995. There were no significant differences in patient demographics or the extent of venous thromboembolic (VTE) disease during this period except for an increase in median age. Filter placement by interventional radiologists remained approximately 50% of the total whereas placement by vascular/trauma surgeons increased to 24% and placement by cardiologists decreased to 29% (P < .001). In 2005, a smaller percentage of filters were placed for absolute indications, while filter placements for relative and prophylactic indications increased over the same time period, especially among cardiologists (P = .02). Potentially retrievable filters are increasingly being used for prophylaxis; however, only 2.4% were retrieved. An increasing number of filters were placed in patients with only infrapopliteal deep venous thrombosis (P = .07). A shift was seen to lower profile and removable filter types. Long-term patient follow-up showed little change in disease progression or in morbidity and mortality of filter insertion. CONCLUSIONS: Technological and practice pattern changes have led to an increase in filters inserted by vascular and trauma surgeons in the operating room and intensive care units. Increased diagnosis of VTE disease and newer low profile delivery systems in patients may also have contributed to the significant increase in filter placement. A shift in indications for placement from absolute toward relative indications and prophylaxis is evident over time and across providers, indicating the need for consensus development of appropriate criteria.

Contemporary outcomes for carotid endarterectomy at a large community-based academic health center.

The North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Asymptomatic Carotid Atherosclerosis Study (ACAS) demonstrated the efficacy of carotid endarterectomy (CEA), but these studies were published 15 and 11 years ago, respectively. We hypothesized that present clinical results of CEA have improved compared with those reported by NASCET/ACAS. Every patient having CEA from January 1999 through December 2003 was reviewed as part of a continuous quality-assurance program. Patient demographics and risk factors were recorded; high-risk patients were identified using inclusion criteria for high-risk carotid stent trials. Primary end points recorded were all neurologic events, deaths, and myocardial infarctions (MIs). Outcomes were reported individually or as combined neurologic events and deaths (traditional NASCET/ACAS methodology) and, similar to recent carotid stent trials, individually, combined, and as a composite that included MI. A total of 1,927 CEAs were performed, 1,140 in men (59%) and 787 in women (41%). The average age was 72 +/- 9 years; 21% of patients were age 80 or older. Symptomatic patients accounted for 717 procedures (37%). Perioperative neurologic event, death, and MI occurred in 1.0%, 0.5%, and 1.3% of patients, respectively. The combined neurologic event and death rate was 1.3% (symptomatic = 1.8%, asymptomatic = 1.1%). High-risk patients comprised 54% of the cohort; the neurologic event and death rate for this group was 1.6%. The composite end point including MI was 3.4%. Severe coronary artery disease and prior ipsilateral CEA significantly correlated with a higher incidence of primary end point complications. In contemporary practice, the perioperative neurologic event rate is significantly less than reported in NASCET/ACAS. Perioperative death and MI rates were similar to those seen in NASCET/ACAS. Neurologic events and death rates were not different between high- and low-risk groups. These data may serve as a guide for the modern vascular specialist weighing open and endovascular options for treatment of carotid artery occlusive disease in both high- and low-risk patients.

Diagnosis of total internal carotid occlusions with duplex ultrasound and ultrasound contrast.

It remains a significant technical challenge for duplex ultrasound to accurately differentiate between total and near total internal carotid artery (ICA) occlusions. We have evaluated the efficacy of an ultrasound contrast agent combined with improved imaging techniques in patients with suspected carotid artery occlusions. Patients identified by conventional duplex ultrasound between January and August 2003 as having a possible ICA occlusion were eligible for study. A 1 mL bolus of ultrasound contrast agent was injected into a 50 mL bag of normal saline and given intravenously at a rate of approximately 4-5 mL/minute. Ultrasound imaging and spectral Doppler analysis were done using tissue harmonic imaging for optimum contrast agent to soft tissue discrimination, or with the direct B-mode imaging of blood flow to maximize the brightness of the circulating contrast agent. Ten patients were identified, 6 men and four women with a mean age of 68.3 years. Nine suspected total ICA occlusions were unilateral and 1 was bilateral. Imaging with contrast agent confirmed occlusion of the ICA in 7 of 10 patients; 3 patients had near-total occlusion with flow detected in the distal ICA by spectral and color Doppler. All 3 of these near-total occlusions were ultimately confirmed by either conventional or magnetic resonance carotid angiography. The contrast agent was most beneficial in improving the detection of minimal flow beyond a severe stenosis and in evaluating flow dynamics in the presence of severely calcified plaque. We conclude that the use of an ultrasound contrast agent with newer duplex ultrasound imaging techniques can reliably distinguish total from near-total internal carotid artery occlusions. Future prospective studies should be able to define the efficacy of ultrasound contrast agents in improving the overall diagnostic accuracy of duplex ultrasound in technically difficult cases and in patients with complex peripheral vascular disease.

Lysyl oxidase expression in bronchogenic carcinoma.

BACKGROUND: Lysyl oxidase catalyzes a key step in the cross-linking of collagen and elastin in the extracellular matrix. Recent studies have documented differential lysyl oxidase expression in the stromal reaction to colon, breast, prostate, and lung cancer. The present study was undertaken to test the hypothesis that lysyl oxidase mRNA and protein expression decrease with advancing tumor stage in patients with bronchogenic carcinoma. METHODS: Tumor specimens were obtained from 17 patients undergoing resection for bronchogenic carcinoma. Real-time polymerase chain reaction was used to determine steady-state lysyl oxidase mRNA expression, and protein expression was qualitatively assessed by immunohistochemistry. RESULTS: Real-time polymerase chain reaction studies documented a 3.4-fold graded decrease in lysyl oxidase mRNA levels as tumors progressed from stage I to IV. Similar qualitative changes in lysyl oxidase protein expression were demonstrated by immunohistochemistry. CONCLUSIONS: These results support the hypothesis that variations in lysyl oxidase expression may correlate with the invasive and metastatic potential of bronchogenic carcinoma.

Nitric oxide-releasing biopolymers inhibit thrombus formation in a sheep model of arteriovenous bridge grafts.

OBJECTIVES: Nitric oxide (NO), produced by normal vascular endothelial cells, reduces platelet aggregation and thrombus formation. NO-releasing biopolymers have the potential to prolong vascular graft and stent patency without adverse systemic vasodilation. METHODS: 5-mm polyurethane vascular grafts coated with a polymer containing the NO-donor dialkylhexanediamine diazeniumdiolate were implanted for 21 days in a sheep arteriovenous bridge-graft model. RESULTS: Eighty percent (4/5) of grafts coated with the NO-releasing polymer remained patent through the 21 day implantation period, compared to fifty percent (2/4) of sham-coated grafts and no (0/3) uncoated grafts. Thrombus-free surface area (+/-SEM) of explanted grafts was significantly increased in NO-donor coated grafts (98.2% +/- 0.9%) compared with sham-coated (79.2% +/- 8.6%) and uncoated (47.2% +/- 5.4%) grafts ( P = .00046). Examination of the graft surface showed no adherent thrombus or platelets and no inflammatory cell infiltration in NO-donor coated grafts, while control grafts showed adherent complex surface thrombus consisting of red blood cells in an amorphous fibrin matrix, as well as significant red blood cell and inflammatory cell infiltration into the graft wall. CONCLUSION: In this study we determined that local NO release from the luminal surface of prosthetic vascular grafts can reduce thrombus formation and prolong patency in a model of prosthetic arteriovenous bridge grafts in adult sheep. These findings may translate into improved function and improved primary patency rates in small-diameter prosthetic vascular grafts.

Duplex ultrasound recognition of spontaneous carotid dissection--a case report and review of the literature.

Spontaneous dissection of the internal carotid artery is an uncommon entity with a variable clinical presentation. A high index of suspicion is required to make the diagnosis, and prompt diagnosis and treatment with anticoagulation are essential for improved patient outcomes. Duplex ultrasound provides a safe and reliable imaging modality for early diagnosis and follow-up. The authors present a case of spontaneous internal carotid artery dissection with duplex ultrasound findings and a review of the literature.

Lysyl oxidase expression in a rat model of arterial balloon injury.

OBJECTIVE: Traditional therapies for arteriosclerotic disease often fail as a result of an exaggerated fibroproliferative response (recurrent stenosis) at the site of the intervention. Lysyl oxidase, secreted by activated vascular smooth muscle cells and fibroblasts, catalyzes a key step in the cross-linking and stabilization of collagen and elastin in the vascular wall. We hypothesized that lysyl oxidase messenger RNA (mRNA) and protein expression are time-dependent and precede collagen accumulation and luminal narrowing after arterial balloon injury in the rat. METHODS: A 2F balloon-tipped catheter was used to injure the right common carotid artery in male Sprague-Dawley rats. Injured right and control (uninjured) left common carotid arteries were harvested at 0, 0.25, 1, 3, 7, 14, 21, 28, and 60 days for mRNA quantitation and immunohistochemical analysis. Steady-state lysyl oxidase mRNA levels were quantitated with real-time reverse transcription polymerase chain reaction (TaqMan). Immunohistochemical staining with antibodies to alpha-smooth muscle cell actin and lysyl oxidase, and Movat pentachrome staining were performed for qualitative assessment of changes in the cellular and extracellular matrix components of the vessel wall. Post-injury intimal area was measured from hematoxylin and eosin-stained specimens at each time point. RESULTS: When compared with sham-operated control arteries, lysyl oxidase expression in balloon-injured arteries increased significantly to 212% by day 3 after injury, and remained elevated through day 21, with a decrease toward baseline levels by day 28. Lysyl oxidase protein expression did not peak until day 14, and persisted through day 28. Collagen accumulation peaked at day 28, corresponding to the maximal increase in intimal area, with later accumulation of proteoglycans and ground substance in the intimal lesion. CONCLUSION: Our results indicate that lysyl oxidase mRNA and protein expression is time-dependent after balloon injury of the rat carotid artery and that expression appears to precede maximal collagen accumulation and corresponding increases in intimal area. This suggests that lysyl oxidase may have an important role in stabilization of collagen and elastin at sites of vascular injury and that modulation of lysyl oxidase activity may be a viable method to prevent or reduce recurrent stenosis. CLINICAL RELEVANCE: Failure of traditional therapies for ischemic arteriosclerotic disease is often due to an exaggerated fibroproliferative response (recurrent stenosis) at the site of intervention. Recurrent stenosis can be viewed as an injury-repair process, with an initial stage characterized by cellular proliferation followed by deposition of extracellular matrix. This study focuses on lysyl oxidase, a key enzyme involved in stabilization of collagen and elastin. This study demonstrates that lysyl oxidase messenger RNA and protein expression are time-dependent, preceding collagen accumulation and corresponding increases in intimal area. Accumulation of extracellular matrix is a major factor in growth of the restenotic lesion, and modulation of lysyl oxidase activity may offer a therapeutic method for decreasing or preventing recurrent stenosis.

Gastrointestinal complications following infrarenal endovascular aneurysm repair.

Gastrointestinal complications are known to occur after open elective aortic aneurysm repair. This leads to increased morbidity, mortality, length of stay, and hospital costs. The authors hypothesize a change in the character and/or frequency of early postoperative gastrointestinal complications after endovascular aneurysm repair as compared to open abdominal aortic repair. This is a retrospective cohort study in which the medical records of 153 consecutive patients who underwent endovascular infrarenal aneurysm repair from November 1998 to August 2001 were reviewed for gastrointestinal complications. Of these 153 patients, 9 (5.9%) had postoperative gastrointestinal complications. Three patients (1.9%) underwent exploratory laparotomy for small bowel obstruction. One patient had had a right hemicolectomy for cancer 2 years before stent graft placement. This patient needed a partial small bowel resection. One patient had had a right hemicolectomy 4 months before stent graft placement; he had lysis of adhesions with no bowel resection. A third patient underwent operative repair of an incarcerated inguinal hernia. Six patients (3.9%) had paralytic ileus that was treated by nasogastric tube or observation resulting in an extended hospital length of stay. All cases of ileus resolved without any operative intervention. No patients in this series developed any intestinal ischemia, pancreatitis, cholecystitis, or gastrointestinal bleeding. After endovascular aneurysm repair, gastrointestinal complications such as ileus and postoperative small bowel obstruction are seen with a similar frequency as after open aortic repair. This occurs despite the absence of a laparotomy with mesenteric dissection and evisceration. In this series, these complications are associated with longer hospital length of stay but no increased mortality rate. No instances of colonic ischemia, pancreatitis, cholecystitis, or gastrointestinal bleeding were seen in this series.

Reliability of extracranial carotid artery duplex ultrasound scanning: value of vascular laboratory accreditation.

OBJECTIVES: The purpose of this study was to evaluate the reliability of carotid duplex ultrasound scanning performed by nonaccredited vascular laboratories and to assess the clinical effect on patient management. METHODS: We retrospectively reviewed concordance of findings of carotid duplex ultrasound scanning between laboratories accredited by the Intersocietal Commission for Accreditation of Vascular Laboratories and nonaccredited laboratories in 174 patients with asymptomatic disease referred to tertiary care community hospitals for surgical evaluation for carotid endarterectomy (CEA) between January 2001 and December 2002, and evaluated changes in clinical management made on the basis of repeat examinations. RESULTS: Concordant findings were noted in 171 of 348 arteries (49%), predominantly those with minimal or mild disease (114 arteries; 67%). Discordant findings of no clinical significance were found in 54 arteries (16%). Clinically significant discordant findings were noted in 123 arteries (35%) in 107 patients (61%). In 104 arteries (88 patients) stenosis was overestimated by the nonaccredited laboratory secondary to technical error (19 arteries), use of B-mode imaging data alone (36 arteries), and use of inappropriate velocity criteria (49 arteries). None of these patients underwent CEA. Stenosis was significantly underestimated in 19 arteries (19 patients); all of these patients underwent uncomplicated CEA. CONCLUSIONS: Incorrect physician interpretation of data is the most common cause of error in carotid duplex ultrasound scanning performed in nonaccredited vascular laboratories. Results of carotid duplex ultrasound scanning from nonaccredited laboratories should be considered with extreme caution, and do not appear reliable in planning treatment of obstructive disease.

Duplex ultrasound imaging with an ultrasound contrast agent: the economic alternative to CT angiography for aortic stent graft surveillance.

The use of endovascular stent graft repair for aortic aneurysmal disease has become increasingly common, with the added requirement for close postoperative surveillance to detect the presence of endoleaks or graft migration. The most commonly used technique for surveillance is computed tomography (CT) angiography, with the need for intravenous contrast posing 1 limitation in those patients with renal dysfunction and the cost of this testing presenting an economic limitation. Early results of duplex imaging in the authors' Vascular Laboratory using an intravenous ultrasound contrast agent have shown sensitivity and specificity equivalent to those of CT angiography, with no evidence of any related morbidity. They have evaluated the cost effectiveness of using duplex ultrasound imaging as the primary surveillance technique for postoperative follow-up in aortic stent graft patients. Surveillance protocols now require that 8 follow-up examinations be performed in the first 3 years after stent graft placement. The charges for CT angiography in their institution average 2,779 dollars per study, for a 3-year total of 22,232 dollars per patient. The charges for aortic duplex ultrasound average 525 dollars per study, with a 3-year total of 4,200 dollars per patient. Adding the cost of routine abdominal radiographs to confirm stent graft position (147 dollars per study) would bring this 3-year total to 5,376 dollars, a savings of 16,856 dollars per patient. For every 100 patients who are followed up after stent graft placement, this represents a 3-year savings of more than 1.6M dollars. Promising early results of duplex ultrasound imaging with an intravenous contrast agent show sensitivity and specificity equivalent to those of CT angiography in detecting aneurysm size and graft endoleaks or other hemodynamic abnormalities. If these results can be demonstrated in larger patient series, this technique should become the method of choice for stent graft surveillance, for it offers very significant economic advantages and avoids the complications of intravenous contrast-induced renal dysfunction.

Transrenal fixation of endovascular stent-grafts for infrarenal aortic aneurysm repair: mid-term results.

PURPOSE: We evaluated mid-term results of a single-center consecutive series of endovascular stent-grafts implanted for aortic aneurysm repair with transrenal fixation, to determine clinical outcome, aneurysm anatomy, renal artery patency, and renal complications. METHODS: Modular stent-grafts were placed with transrenal fixation in 37 patients between November 1998 and July 2000. Follow-up evaluation included clinical examination, laboratory evaluation of serum creatine concentration, computed tomographic angiography, and renal duplex scanning. RESULTS: Thirty-seven patients underwent transrenal fixation of aortic stent-grafts as part of a Phase II US Food and Drug Administration study. Two patients subsequently underwent follow-up at institutions closer to their homes, and thus provided clinical information but no long-term renal or aneurysm morphologic data. There were no perioperative deaths. Five patients died during follow-up, at a mean of 9 months, because of myocardial infarction in 4 patients and respiratory failure in 1 patient. Thirty patients, ages 75 +/- 8 years, have been followed up for 28.5 +/- 7.2 months. Aneurysm diameter at follow-up was 5.0 +/- 0.8 cm, compared with 5.7 +/- 0.8 cm preoperatively. In 5 patients, endoleak developed during follow-up: 1 type I leak was treated with an aortic cuff, with temporary stabilization of the aneurysm and correction of the endoleak; 2 type II endoleaks were treated with translumbar coil embolization, and 1 resolved spontaneously; and 1 type III endoleak was treated with a combination of coil embolization and stent-graft extension to cover a graft defect. Preoperatively, serum creatinine concentration was normal in 23 patients, but increased persistently in 2 patients and was abnormal in 7 patients. Postoperatively, creatine concentration increased in 4 patients to greater than 20% of baseline level. Seventeen patients had no evidence of renal artery stenosis, compared with 13 patients with renal artery stenosis. Of 41 normal renal arteries, 90% remained unchanged, 1 became occluded, 3 demonstrated 60% stenosis. Nephrectomy was necessary in 1 patient because of cancer. Of 19 abnormal renal arteries, progression of disease was noted in 3 arteries. CONCLUSIONS: Transrenal fixation of aortic stent-grafts can be performed with acceptable mid-term outcome with respect to mortality, need for follow-up intervention, and aneurysm exclusion with protection from rupture. Postprocedural stenosis can develop in both normal and abnormal renal arteries. Rate of progression of disease was greater in patients with preprocedural renal dysfunction compared with patients with normal renal arteries. This is merely an observation, and may not be related to transrenal fixation. Long-term follow up is needed.