Cognitive impairment in asymptomatic carotid artery stenosis is associated with abnormal segments in the Circle of Willis.

OBJECTIVE: Our group has previously demonstrated that patients with asymptomatic carotid artery stenosis (ACAS) demonstrate cognitive impairment. One proposed mechanism for cognitive impairment in patients with ACAS is cerebral hypoperfusion due to flow-restriction. We tested whether the combination of a high-grade carotid stenosis and inadequate cross-collateralization in the Circle of Willis (CoW) resulted in worsened cognitive impairment. METHODS: Twenty-four patients with high-grade (≥70% diameter-reducing) ACAS underwent carotid duplex ultrasound, cognitive assessment, and 3D time-of-flight magnetic resonance angiography. The cognitive battery consisted of nine neuropsychological tests assessing four cognitive domains: learning and recall, attention and working memory, motor and processing speed, and executive function. Raw cognitive scores were converted into standardized T-scores. A structured interpretation of the magnetic resonance angiography images was performed with each segment of the CoW categorized as being either normal or abnormal. Abnormal segments of the CoW were defined as segments characterized as narrowed or occluded due to congenital aplasia or hypoplasia, or acquired atherosclerotic stenosis or occlusion. Linear regression was used to estimate the association between the number of abnormal segments in the CoW, and individual cognitive domain scores. Significance was set to P < .05. RESULTS: The mean age of the patients was 66.1 ± 9.6 years, and 79.2% (n = 19) were male. A significant negative association was found between the number of abnormal segments in the CoW and cognitive scores in the learning and recall (ß = -6.5; P = .01), and attention and working memory (ß = -7.0; P = .02) domains. There was a trend suggesting a negative association in the motor and processing speed (ß = -2.4; P = .35) and executive function (ß = -4.5; P = .06) domains that did not reach significance. CONCLUSIONS: In patients with high-grade ACAS, the concomitant presence of increasing occlusive disease in the CoW correlates with worse cognitive function. This association was significant in the learning and recall and attention and working memory domains. Although motor and processing speed and executive function also declined numerically with increasing abnormal segments in the CoW, the relationship was not significant. Since flow restriction at a carotid stenosis compounded by inadequate collateral compensation across a diseased CoW worsens cerebral perfusion, our findings support the hypothesis that cerebral hypoperfusion underlies the observed cognitive impairment in patients with ACAS.

Lack of association between cognitive impairment and systemic inflammation in asymptomatic carotid stenosis.

BACKGROUND: Asymptomatic carotid atherosclerotic stenosis (ACAS) is associated with cognitive impairment. Systemic inflammation occurs in patients with systemic atherosclerosis and is also associated with cognitive impairment. The goal of this study was to determine if cognitive impairment in patients with ACAS is the result of systemic inflammation. METHODS: A cross-sectional analysis of 104 patients (63 patients with ACAS, 41 controls) with cognitive function and inflammatory biomarker assessments was performed. Venous blood was assayed for proinflammatory biomarkers (IL-1ß, IL-6, IL-6R, IL-8, IL-17, tumor necrosis factor-α, matrix metalloproteinase [MMP]-1, MMP-2, MMP-7, MMP-9, vascular cell adhesion molecule, and high-sensitivity C-reactive protein). The patients also underwent comprehensive cognitive testing to compute five domain-specific cognitive scores per patient. We first assessed the associations between carotid stenosis and cognitive function, and between carotid stenosis and systemic inflammation in separate regression models. We then determined whether cognitive impairments persisted in patients with carotid stenosis after accounting for inflammation by adjusting for inflammatory biomarker levels in a combined model. RESULTS: Patients with ACAS and control patients differed in age, race, coronary artery disease prevalence, and education. Stenosis patients had worse cognitive scores in two domains: learning and memory (P = .05) and motor and processing speed (P = .002). Despite adjusting for inflammatory biomarker levels, patients with ACAS still demonstrated deficits in the domains of learning and memory and motor and processing speed. CONCLUSIONS: Although systemic atherosclerosis-induced inflammation is a well-recognized cause for cognitive impairment, our data suggest that it is not the primary underlying mechanism behind cognitive impairments seen in ACAS. Cognitive impairments in learning and memory and motor and processing speed seen in patients with ACAS persist after adjusting for systemic inflammation. Thus, alternative mechanisms should be explored to account for the observed functional impairments.

Revascularization for asymptomatic carotid artery stenosis improves balance and mobility.

OBJECTIVE: Balance and mobility function worsen with age, more so for those with underlying chronic diseases. We recently found that asymptomatic carotid artery stenosis (ACAS) restricts blood flow to the brain and might also contribute to balance and mobility impairment. In the present study, we tested the hypothesis that ACAS is a modifiable risk factor for balance and mobility impairment. Our goal was to assess the effect of restoring blood flow to the brain by carotid revascularization on the balance and mobility of patients with high-grade ACAS (≥70% diameter-reducing stenosis). METHODS: Twenty adults (age, 67.0 ± 9.4 years) undergoing carotid endarterectomy for high-grade stenosis were enrolled. Balance and mobility assessments were performed before and 6 weeks after revascularization. These included the Short Physical Performance Battery, the Berg Balance Scale, the Four Square Step Test, the Dynamic Gait Index (DGI), the Timed Up and Go test, gait speed, the Mini-Balance Evaluation Systems Test (Mini-BESTest), and the Walking While Talking complex test. RESULTS: Consistent with our previous findings, patients demonstrated reduced scores on the Short Physical Performance Battery, Berg Balance Scale, DGI, and Timed Up and Go test and in gait speed. Depending on the outcome measure, 25% to 90% of the patients had scored in the impaired range at baseline. After surgery, significant improvements were observed in the outcome measures that combined walking with dynamic movements, including the DGI (P = .02) and Mini-BESTest (P = .002). The proportion of patients with Mini-BESTest scores indicating a high fall risk had decreased significantly from 90% (n = 18) at baseline to 40% (n = 8) after surgery (P = .02). We used Pearson's correlations to examine the relationship between balance and mobility before surgery and the change after surgery. Patients with lower baseline DGI and Mini-BESTest scores demonstrated the most improvement after surgery (r = -0.59, P = .006; and r = -0.70, P = .001, respectively). CONCLUSIONS: Carotid revascularization improved patients' balance and mobility, especially for measures that combine walking and dynamic movements. The greatest improvements were observed for the patients who had been most impaired at baseline.

Intraoperative consultation of vascular surgeons is increasing at a major American trauma center.

OBJECTIVE: Vascular surgeons are often called to aid other surgical specialties for complex exposure, hemorrhage control, or revascularization. The evolving role of the vascular surgeon in the management of intraoperative emergencies involving trauma patients remains undefined. The primary aims of this study included determining the prevalence of intraoperative vascular consultation in trauma, describing how these interactions have changed over time, and characterizing the outcomes achieved by vascular surgeons in these settings. We hypothesized that growing endovascular capabilities of vascular surgeons have resulted in an increased involvement of vascular surgery faculty in the management of the trauma patient over time. METHODS: A retrospective review of all operative cases at a single level I trauma center where a vascular surgeon was involved, but not listed as the primary surgeon, between 2002 and 2017 was performed. Cases were abstracted using Horizon Surgical Manager, a documentation system used in our operating room to track staff present, the type of case, and use. All elective cases were excluded. RESULTS: Of the 256 patients initially identified, 22 were excluded owing to the elective or joint nature of the procedure, leaving 234 emergent operative vascular consultations. Over the 15-year study period, a 529% increase in the number of vascular surgery consultations was seen, with 65% (n = 152) being intraoperative consultations requiring an immediate response. Trauma surgery (n = 103 [44%]) and orthopedic surgery (n = 94 [40%]) were the most common consulting specialties, with both demonstrating a trend of increasing consultations over time (general surgery, 1400%; orthopedic surgery, 220%). Indications for consultation were extremity malperfusion, hemorrhage, and concern for arterial injury. The average operative time for the vascular component of the procedures was 2.4 hours. Of patients presenting with ischemia, revascularization was successful in 94% (n = 116). Hemorrhage was controlled in 99% (n = 122). In-hospital mortality was relatively low at 7% (n = 17). Overall, despite the increase in intraoperative vascular consultations over time, a concomitant increase in the proportion of procedures done using endovascular techniques was not seen. CONCLUSIONS: Vascular surgeons are essential team members at a level I trauma center. Vascular consultation in this setting is often unplanned and often requires immediate intervention. The number of intraoperative vascular consultations is increasing and cannot be attributed solely to an increase in endovascular hemorrhage control, and instead may reflect the declining experience of trauma surgeons with vascular trauma. When consulted, vascular surgeons are effective in quickly gaining control of the situation to provide exposure, hemorrhage control, or revascularization.

Asymptomatic carotid artery stenosis is associated with cerebral hypoperfusion.

OBJECTIVE: We have shown that almost 50% of patients with asymptomatic carotid stenosis (ACS) will demonstrate cognitive impairment. Recent evidence has suggested that cerebral hypoperfusion is an important cause of cognitive impairment. Carotid stenosis can restrict blood flow to the brain, with consequent cerebral hypoperfusion. In contrast, cross-hemispheric collateral compensation through the Circle of Willis, and cerebrovascular vasodilation can also mitigate the effects of flow restriction. It is, therefore, critical to develop a clinically relevant measure of net brain perfusion in patients with ACS that could help in risk stratification and in determining the appropriate treatment. To determine whether ACS results in cerebral hypoperfusion, we developed a novel approach to quantify interhemispheric cerebral perfusion differences, measured as the time to peak (TTP) and mean transit time (MTT) delays using perfusion-weighted magnetic resonance imaging (PWI) of the whole brain. To evaluate the utility of using clinical duplex ultrasonography (DUS) to infer brain perfusion, we also assessed the relationship between the PWI findings and ultrasound-based peak systolic velocity (PSV). METHODS: Structural and PWI of the brain and magnetic resonance angiography of the carotid arteries were performed in 20 patients with ≥70% ACS. DUS provided the PSV, and magnetic resonance angiography provided plaque geometric measures at the stenosis. Volumetric perfusion maps of the entire brain from PWI were analyzed to obtain the mean interhemispheric differences for the TTP and MTT delays. In addition, the proportion of brain volume that demonstrated a delay in TTP and MTT was also measured. These proportions were measured for increasing severity of perfusion delays (0.5, 1.0, and 2.0 seconds). Finally, perfusion asymmetries on PWI were correlated with the PSV and stenosis features on DUS using Pearson's correlation coefficients. RESULTS: Of the 20 patients, 18 had unilateral stenosis (8 right and 10 left) and 2 had bilateral stenoses. The interhemispheric (left-right) TTP delays measured for the whole brain volume identified impaired perfusion in the hemisphere ipsilateral to the stenosis in 16 of the 18 patients. More than 45% of the patients had had ischemia in at least one half of their brain volume, with a TTP delay >0.5 second. The TTP and MTT delays showed strong correlations with PSV. In contrast, the correlations with the percentage of stenosis were weaker. The correlations for the PSV were strongest with the perfusion deficits (TTP and MTT delays) measured for the whole brain using our proposed algorithm (r = 0.80 and r = 0.74, respectively) rather than when measured on a single magnetic resonance angiography slice as performed in current clinical protocols (r = 0.31 and r = 0.58, respectively). CONCLUSIONS: Interhemispheric TTP and MTT delay measured for the whole brain using PWI has provided a new tool for assessing cerebral perfusion deficits in patients with ACS. Carotid stenosis was associated with a detectable reduction in ipsilateral brain perfusion compared with the opposite hemisphere in >80% of patients. The PSV measured at the carotid stenosis using ultrasonography correlated with TTP and MTT delays and might serve as a clinically useful surrogate to brain hypoperfusion in these patients.

Re-evaluating the safety and effectiveness of the 0.9 ankle-brachial index threshold in penetrating lower extremity trauma.

OBJECTIVE: Current guidelines recommend additional imaging when the ankle-brachial index (ABI) is ≤0.9 after extremity trauma; however, the accuracy of this 0.9 threshold compared with other values has not been evaluated. The primary aim of this study was to compare the safety and effectiveness of various ABI thresholds in predicting lower extremity vascular injuries after penetrating trauma. We hypothesized that a lower ABI threshold can be used safely to avoid unnecessary imaging. METHODS: A retrospective cohort study was performed at a single level I trauma center from January 2015 to December 2017. All patients who presented with penetrating lower extremity trauma and who underwent computed tomography angiography (CTA) were reviewed. Patients taken directly to the operating room without first undergoing CTA or those without documented ABIs were excluded. Demographic information, clinical features of presentation, interventions performed, and outcomes were recorded. P values were obtained using the Kolmogorov-Smirnov test, and a receiver operating characteristic curve was created to compare various ABI thresholds. RESULTS: A total of 47 patients (81% male), with a mean age of 29 years (range, 14-59 years), met inclusion criteria. Of the 17 limbs (36%) with a vascular abnormality seen on CTA, 6 (35%) required an intervention. The distribution of ABIs in injured limbs requiring revascularization was significantly lower (P = .006) than in those that did not require intervention. An ABI threshold of 0.7 is most accurate, with the highest combined sensitivity (83%) and specificity (91%) for detecting vascular injuries requiring revascularization. In addition, the negative predictive value was no different between a threshold of 0.7 (98%) and a threshold of 0.9 (97%), with both thresholds missing one vascular injury (pseudoaneurysm) requiring repair. CONCLUSIONS: The ABI remains reliable in distinguishing between limbs with and limbs without vascular injury requiring revascularization after penetrating lower extremity trauma. A lower threshold can safely be used without compromising the negative predictive value of a screening ABI. Applying a threshold of 0.7 to our cohort would have avoided 51% (24) of the CTA studies performed without missing additional vascular injuries requiring repair.

Lowering the Ankle-Brachial Index Threshold in Blunt Lower Extremity Trauma May Prevent Unnecessary Imaging.

BACKGROUND: Current algorithms for the management of blunt lower extremity trauma recommend additional imaging in patients presenting with soft signs of vascular injury and an ankle-brachial index (ABI) less than 0.9. The aim of this study is to analyze lower extremity computed tomography angiographies (CTAs) to determine the incidence and characteristics of patients sustaining vascular injury from blunt lower extremity trauma. We hypothesized that a lower ABI threshold can avoid unnecessary imaging without missing clinically significant vascular injury. METHODS: A single-center, retrospective review of all consecutive patients who presented to a level 1 trauma center with blunt lower extremity trauma and underwent a CTA from January 2015 to December 2017 was conducted. Baseline demographics, clinical features, and outcomes were recorded. Patients without documented ABIs were excluded. A receiver operating characteristic curve was used to define the ABI threshold. RESULTS: One hundred twenty-five patients (133 injured limbs) met inclusion criteria. The mean age was 44 years (range 9-96), and 74% of the patients were male. A vascular abnormality was identified on CTA in 65 limbs (48.9%), of which only 8 (12%) required intervention. The ABIs in these 8 injured limbs were between 0 and 0.6. An ABI threshold of 0.6 maximized the balance between sensitivity (100%) and specificity (87%) and missed no injuries requiring revascularization. CONCLUSIONS: The ABI remains useful in evaluating blunt lower extremity trauma. A lower ABI threshold in patients presenting with soft signs of vascular injury after blunt trauma may avoid unnecessary imaging without missing vascular injuries requiring intervention. Further prospective studies are needed to validate the safety and effectiveness of a lower ABI threshold.

Endovascular Reconstruction of the Hepatic Arterial System for the Management of Mycotic Pseudoaneurysm in a Liver Transplant Patient.

BACKGROUND: Hepatic artery pseudoaneurysm is a rare but very morbid complication after liver transplant. Treatment options include ligation or endovascular embolization, followed by revascularization. We describe a new endovascular approach by stent exclusion in a high-risk patient. RESULTS: A 62-year-old male who received a second liver transplant after failed allograft presented with hemobilia and was diagnosed with a hepatic artery pseudoaneurysm in the setting of infection. Given his hostile abdomen, an endovascular approach was sought. We excluded the mycotic pseudoaneurysm with multiple covered stent grafts extending from the common hepatic artery to the right and left hepatic arteries. He was discharged with long-term antibiotics. On his 6-month follow-up visit, his stent was patent and hepatic function was stable. CONCLUSIONS: Endovascular stent-graft placement for management of hepatic artery pseudoaneurysm after liver transplant should be considered as a lower morbidity alternative to surgical repair, even in the setting of infection.

The Incidence of Ischemic Colitis after Repair of Ruptured Abdominal Aortic Aneurysms Is Decreasing in the Endovascular Era.

BACKGROUND: Ischemic colitis (IC) is a well-described complication of ruptured abdominal aortic aneurysms (rAAAs). The purpose of this study was to compare the incidence of IC in patients with rAAA undergoing open repair (OR) versus endovascular aneurysm repair (EVAR) at a single institution. In addition, we analyzed the incidence of IC before and after the implementation of a formal rupture AAA protocol (rEVAR protocol). METHODS: A retrospective analysis of prospectively collected data on all patients presenting with rAAA to our institution between January 2002 and October 2013 was performed. Variables were analyzed for association with IC. Comparisons were made using Pearson's chi-squared test or Fisher's exact test for categorical variables, Student's t-test for continuous variables, and logistic regression for multivariate analysis. Significance was set at P < 0.05. RESULTS: Three hundred three patients with rAAA presented over the 10-year study period. One hundred ninety-one patients underwent OR and 89 patients underwent endovascular repair. Twenty-three patients died either in the emergency department, en route to the operating room, or after choosing comfort care. Predictive factors of IC included estimated blood loss, corresponding need for resuscitation, and duration of procedure. Of patients who underwent OR, the rate of IC was 21% (40/191). This was significantly higher than patients who underwent EVAR, 7% (6/89), P < 0.05. The type of intervention did not influence 30-day mortality in patients with IC. However, only 17% (1/6) of patients who had IC following EVAR required colectomy versus 48% (19/40) of patients with IC following OR (P = 0.21). Implementation of our formal rEVAR protocol decreased the incidence of IC significantly from 37.1% (36/97) to 6.4% (10/157), P < 0.001. CONCLUSIONS: The incidence of IC has decreased significantly in the endovascular era but continues to portend a poor prognosis. Implementation of a formal, multidisciplinary rEVAR protocol in our institution decreased the incidence of IC.

Outcomes after retroflexed gracilis muscle flap for vascular infections in the groin.

OBJECTIVE: Multiple catheterizations and procedures on the femoral arteries can increase the risk of infection and eventual destruction of the overlying skin and subcutaneous tissue. Without adequate tissue coverage, vascular structures are exposed and, thus, vulnerable to disruption. This can lead to loss of limb and/or life and carries a significant mortality. We hypothesized that gracilis muscle flap (GMF) was a reliable adjunct in providing healthy tissue coverage for a complex surgical problem. METHODS: Retrospective review of charts was performed on all patients who had undergone GMF for groin infections at a tertiary care medical center. RESULTS: From 1997 to 2012, GMF was performed in 68 limbs (64 patients) by vascular surgeons for infectious etiology to cover the common femoral artery. At the time the GMF was placed, the femoral artery had synthetic graft/patch in 14 limbs, whereas 54 limbs had procedures with autologous conduit. Complete healing was achieved in 58 (85%) limbs. Treatment was deemed not successful in 10 limbs where patients continued to have persistent infection. Six out of 10 limbs had anastomosis disruption requiring emergent ligation of the common femoral artery. Nine patients died during the perioperative period (30-day). There were a total of 13 amputations in 12 patients. Limb salvage was achieved in 55 limbs (81%). Univariate analysis suggested that patients that had revascularization procedures with synthetic graft had a higher complication rate compared with autologous/vein reconstruction (24% vs 5%; P = .021). This group also has a higher rate of persistent infection compared with the autologous group (24% vs 2%; P = .006). Patients older than 75 years at the time of GMF had a higher incidence of GMF-related complications (57% vs 5%; P = .04). Multivariate analysis confirmed that presence of prosthesis led to higher incidence treatment failures and muscle flap complications at the surgical site (odds ratio, 6.6; P = .04; and odds ratio, 13.3; P = .03, respectively). CONCLUSIONS: GMF is technically simple to perform and provides durable soft tissue coverage with a high rate of healing for complex groin wounds even in the presence of synthetic conduit.