Peripheral artery disease causes consistent gait irregularities regardless of the location of leg claudication pain.

BACKGROUND: The most common symptom of peripheral artery disease (PAD) is intermittent claudication that involves the calf, thigh, and/or buttock muscles. How the specific location of this leg pain is related to altered gait, however, is unknown. OBJECTIVES: We hypothesized that because the location of claudication symptoms uniquely affects different leg muscle groups in people with PAD, this would produce distinctive walking patterns. METHODS: A total of 105 participants with PAD and 35 age-matched older volunteers without PAD (CTRL) were recruited. Participants completed walking impairment questionnaires (WIQ), Gardner-Skinner progressive treadmill tests, the six-minute walk test, and we performed an advanced evaluation of the biomechanics of their overground walking. Participants with PAD were categorized into 4 groups according to their stated pain location(s): calf only (C, n = 43); thigh and calf (TC, n = 18); buttock and calf (BC, n = 15); or buttock, thigh, and calf (BTC, n = 29). Outcomes were compared between CTRL, C, TC, BC and BTC groups using a one-way ANOVA with post-hoc comparisons to identify and assess statistically significant differences. RESULTS: There were no significant differences between CTRL, C, TC, BC and BTC groups in distances walked or walking speed when either pain-free or experiencing claudication pain. Each participant with PAD had significantly dysfunctional biomechanical gait parameters, even when pain-free, when compared to CTRL (pain-free) walking data. During pain-free walking, out of the 18 gait parameters evaluated, we only identified significant differences in hip power generation during push-off (in C and TC groups) and in knee power absorption during weight acceptance (in TC and BC groups). There were no between-group differences in gait parameters while people with PAD were walking with claudication pain. CONCLUSIONS: Our data demonstrate that PAD affects the ischemic lower extremities in a diffuse manner irrespective of the location of claudication symptoms. DATABASE REGISTRATION: ClinicalTrials.gov NCT01970332.

Peripheral artery disease affects the function of the legs of claudicating patients in a diffuse manner irrespective of the segment of the arterial tree primarily involved.

Different levels of arterial occlusive disease (aortoiliac, femoropopliteal, multi-level disease) can produce claudication symptoms in different leg muscle groups (buttocks, thighs, calves) in patients with peripheral artery disease (PAD). We tested the hypothesis that different locations of occlusive disease uniquely affect the muscles of PAD legs and produce distinctive patterns in the way claudicating patients walk. Ninety-seven PAD patients and 35 healthy controls were recruited. PAD patients were categorized to aortoiliac, femoropopliteal and multi-level disease groups using computerized tomographic angiography. Subjects performed walking trials both pain-free and during claudication pain and joint kinematics, kinetics, and spatiotemporal parameters were calculated to evaluate the net contribution of the calf, thigh and buttock muscles. PAD patients with occlusive disease affecting different segments of the arterial tree (aortoiliac, femoropopliteal, multi-level disease) presented with symptoms affecting different muscle groups of the lower extremity (calves, thighs and buttocks alone or in combination). However, no significant biomechanical differences were found between PAD groups during the pain-free conditions with minimal differences between PAD groups in the claudicating state. All statistical differences in the pain-free condition occurred between healthy controls and one or more PAD groups. A discriminant analysis function was able to adequately predict if a subject was a control with over 70% accuracy, but the function was unable to differentiate between PAD groups. In-depth gait analyses of claudicating PAD patients indicate that different locations of arterial disease produce claudication symptoms that affect different muscle groups across the lower extremity but impact the function of the leg muscles in a diffuse manner generating similar walking impairments.

Renal salvage using stent graft placement after acute renal artery occlusion with prolonged ischemic time.

PURPOSE: To describe a patient with acute renal artery occlusion who underwent successful revascularization procedure after experiencing a protracted ischemic period, which resulted in successful retrieval of renal function. CASE REPORT: A 58-year-old male with a history of left renal artery stenosis and stent graft placement presented with symptoms of chest pain, shortness of breath, and flank pain. The patient was admitted to the Intensive Care Unit with the diagnosis of multiorgan failure and subsequent anuria that led to the initiation of hemodialysis. Computed tomography angiography demonstrated an aortic occlusion along with bilateral proximal renal artery occlusion with reconstitution of the mid to distal renal arteries via collateralization. The patient underwent angioplasty with bilateral renal artery stent-graft placement and successful revascularization of proximal renal arteries. Post-operatively, his renal function and urine output improved, and the patient was able to be weaned off hemodialysis along with the benefit of concurrent amelioration of his renovascular hypertension. CONCLUSION: For select patients with renal artery occlusion, revascularization of the renal arteries may result in dialysis independence and stabilization of renovascular hypertension, despite prolonged time of ischemia.

Preoperative frailty Risk Analysis Index to stratify patients undergoing carotid endarterectomy.

OBJECTIVE: Rapid and objective preoperative assessment of patients undergoing carotid endarterectomy (CEA) remains problematic. Preoperative variables correlate with increased morbidity and mortality, yet no easily implemented tool exists to stratify patients. We determined the relationship between our fully implemented frailty-based bedside Risk Analysis Index (RAI) and complications after CEA. METHODS: Patients undergoing CEA in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database from 2005 to 2011 were included. Variables of frailty RAI were matched to preoperative NSQIP variables, and outcomes including stroke, mortality, myocardial infarction (MI), and length of stay were analyzed. We further analyzed patients who were symptomatic and asymptomatic before CEA. RESULTS: With use of the NSQIP database, 44,832 patients undergoing CEA were analyzed (17,696 [39.5%] symptomatic; 27,136 [60.5%] asymptomatic). Increasing frailty RAI score correlated with increasing stroke, death, and MI (P < .0001) as well as with length of stay. RAI demonstrated increasing risk of stroke and death on the basis of risk stratification (low risk [0-10], 2.1%; high risk [>10], 5.0%). Among patients undergoing CEA, 88% scored low (<10) on the RAI. In symptomatic patients, the risk of stroke and death for patients with a score of ≤10 is 2.9%, whereas if the RAI score is 11 to 15, it is 5.0%; 16 to 20, 6.9%; and >21, 8.6%. In asymptomatic patients, the risk of stroke and death for patients with a score of ≤10 is 1.6%, whereas if the RAI score is 11 to 15, it is 2.9%; 16 to 20, 5.2%; and >21, 6.2%. CONCLUSIONS: Frailty is a predictor of increased stroke, mortality, MI, and length of stay after CEA. An easily implemented RAI holds the potential to identify a limited subset of patients who are at higher risk for postoperative complications and may not benefit from CEA.

Three-dimensional bending, torsion and axial compression of the femoropopliteal artery during limb flexion.

High failure rates of femoropopliteal artery reconstruction are commonly attributed to complex 3D arterial deformations that occur with limb movement. The purpose of this study was to develop a method for accurate assessment of these deformations. Custom-made stainless-steel markers were deployed into 5 in situ cadaveric femoropopliteal arteries using fluoroscopy. Thin-section CT images were acquired with each limb in the straight and acutely bent states. Image segmentation and 3D reconstruction allowed comparison of the relative locations of each intra-arterial marker position for determination of the artery's bending, torsion and axial compression. After imaging, each artery was excised for histological analysis using Verhoeff-Van Gieson staining. Femoropopliteal arteries deformed non-uniformly with highly localized deformations in the proximal superficial femoral artery, and between the adductor hiatus and distal popliteal artery. The largest bending (11±3-6±1 mm radius of curvature), twisting (28±9-77±27°/cm) and axial compression (19±10-30±8%) were registered at the adductor hiatus and the below knee popliteal artery. These deformations were 3.7, 19 and 2.5 fold more severe than values currently reported in the literature. Histology demonstrated a distinct sub-adventitial layer of longitudinally oriented elastin fibers with intimal thickening in the segments with the largest deformations. This endovascular intra-arterial marker technique can quantify the non-uniform 3D deformations of the femoropopliteal artery during knee flexion without disturbing surrounding structures. We demonstrate that 3D arterial bending, torsion and compression in the flexed lower limb are highly localized and are substantially more severe than previously reported.

Rat jugular catheter model of biofilm-mediated infection.

Staphylococcus epidermidis is now recognized as the primary cause of nosocomial catheter-mediated infections. Bacteria may be introduced exogenously via contamination of the catheter hub or insertion site and endogenously from sepsis. The in vivo model described in this chapter examines the infection resulting from hematogenous seeding of jugular vein catheters.

Carotid endarterectomy is superior to carotid angioplasty and stenting for perioperative and long-term results.

OBJECTIVE: Carotid angioplasty and stenting (CAS) has challenged carotid endarterectomy (CEA) as the therapy of choice for carotid disease. This meta-analysis aims at summarizing the most current body of evidence. METHODS: All prospective, controlled clinical trials comparing CEA versus CAS were included. The outcome measures of interest were relative risk (RR) of 30-day stroke, 30-day stroke/death, long-term risk of stroke, and risk of restenosis. RESULTS: The RR of 30-day stroke for CAS was 1.6 times that of CEA (RR 1.6; 95%CI 1.2-2.0, P = .001). The 30-day RR of stroke/death was 1.5 times higher for CAS (RR 1.5; 95%CI 1.1-2.1, P = .008). There was a higher risk of long-term stroke (RR 1.2; 95%CI 1.0-1.5, P = .043). The risk of restenosis was twice for CAS (RR 1.8; 95%CI 1.1-3.1, P = .04). CONCLUSION: The 30-day RR of stroke, stroke/death, long-term risk of stroke, and risk of restenosis are consistently higher for carotid artery stenting (CAS).

A population-based study of risk factors for stroke after carotid endarterectomy using the ACS NSQIP database.

BACKGROUND: The benefit of carotid endarterectomy (CEA) is heavily influenced by the risk of perioperative stroke. Our objective was to use the American College of Surgeons' 2007 and 2008 National Surgical Quality Improvement Program (NSQIP) database to assess the postoperative stroke and death rate after CEA among the more than 180 NSQIP participating hospitals, and to identify the preoperative risk factors. MATERIALS AND METHODS: Univariate analysis included 56 preoperative variables. Outcomes were studied for 30 d. Multivariate logistic regression was used for assessment of risk factors. RESULTS: Of 13,316 patients, 7503 (56.5%) were asymptomatic, while 5770 (43.5%) were symptomatic. Combined stroke or death was seen in 262 patients (2.0%). Postoperative stroke occurred in 186 patients (1.4%). One hundred patients (0.8%) died within 30 d. In asymptomatic and symptomatic patients, stroke or death was seen in 1.3% and 2.9% of patients; stroke in 0.9% and 2% of patients; and death in 0.5% and 1.1% of patients, respectively (all P < 0.001). On multivariate analysis for symptomatic patients, dialysis dependence, chronic open wound, impaired sensorium, and dependent functional status were risk factors for stroke or death (all P < 0.05). Among asymptomatic patients, acute renal failure, corticosteroid use, COPD, paraplegia, and dependent functional status were risk factors for stroke or death (all P < 0.05). CONCLUSIONS: This prospective database confirms that CEA is currently performed with low peri-procedural stroke rate in participating ACS NSQIP hospitals and provides a contemporary framework for comparison of other treatment modalities to CEA. Identification of the above risk factors may help with risk stratification and patient counseling for CEA.

Abnormal joint powers before and after the onset of claudication symptoms.

OBJECTIVE: Claudication is the most common manifestation of peripheral arterial disease, producing significant ambulatory compromise. Our study evaluated patients with bilateral lower limb claudication and characterized their gait abnormality based on advanced biomechanical analysis using joint torques and powers. METHODS: Twenty patients with bilateral claudication (10 with isolated aortoiliac disease and 10 with combined aortoiliac and femoropopliteal disease) and 16 matched controls ambulated on a walkway while 3-dimensional biomechanical data were collected. Patients walked before and after onset of claudication pain. Joint torques and powers at early, mid, and late stance for the hip, knee, and ankle joints were calculated for claudicating patients before and after the onset of claudication pain and were compared to controls. RESULTS: Claudicating patients exhibited significantly reduced hip and knee power at early stance (weight-acceptance phase) due to decreased torques produced by the hip and knee extensors. In mid stance (single-limb support phase), patients had significantly reduced knee and hip power due to the decreased torques produced by the knee extensors and the hip flexors. In late stance (propulsion phase), reduced propulsion was noted with significant reduction in ankle plantar flexor torques and power. These differences were present before and after the onset of pain, with certain parameters worsening in association with pain. CONCLUSIONS: The gait of claudication is characterized by failure of specific and identifiable muscle groups needed to perform normal walking (weight acceptance, single-limb support, and propulsion). Parameters of gait are abnormal with the first steps taken, in the absence of pain, and certain of these parameters worsen after the onset of claudication pain.

Cerebral protection devices reduce periprocedural strokes during carotid angioplasty and stenting: a systematic review of the current literature.

PURPOSE: To compare through a systematic review of published literature the stroke outcomes in protected and unprotected carotid artery stenting (CAS). METHODS: PubMed and Cochrane electronic databases were queried to identify peer-reviewed publications from 1995 to 2007 meeting our pre-defined criteria for inclusion (English language, human only, at least 20 patients reported) and exclusion (procedures performed for the treatment of total occlusion, dissection, or aneurysmal disease; urgently performed procedures; use of covered stents; access other than transfemoral). Information was collected on a standardized data abstraction form for pooled analysis of total strokes within 30 days of procedure in all patients and in symptomatic and asymptomatic subgroups. A random effects meta-analysis of studies with concurrently reported data on protected and unprotected CAS was performed. RESULTS: Initial database query resulted in 2485 articles, of which 134 were included in the final analyses (12,263 protected CAS patients and 11,198 unprotected CAS patients). Twenty-four studies included data on both protected and unprotected CAS. Using pooled analysis of all 134 reports, the relative risk (RR) for stroke was 0.62 (95% CI 0.54 to 0.72) in favor of protected CAS. Subgroup analysis revealed a significant benefit for protected CAS in both symptomatic (RR 0.67; 95% CI 0.52 to 0.56) and asymptomatic (RR 0.61; 95% CI 0.41 to 0.90) patients (p<0.05). Meta-analysis of the 24 studies reporting data on both protected and unprotected stenting demonstrated a relative risk of 0.59 (95% CI 0.47 to 0.73) for stroke, again favoring protected CAS (p<0.001). CONCLUSION: Our systematic review indicated that the use of cerebral protection devices decreased the risk of perioperative stroke with CAS. A well designed randomized trial can further confirm our findings and possibly indicate the device with the best outcomes.

One patent intracranial collateral predicts tolerance of flow reversal during carotid angioplasty and stenting.

Internal carotid artery (ICA) flow reversal is an effective means of cerebral protection during carotid stenting. Its main limitation is that in the absence of adequate collateral flow it may not be tolerated by the patient. The purpose of this study was to determine if preoperative identification of intracranial collaterals with computerized tomographic (CTA) or magnetic resonance (MRA) angiography can predict adequate collateral flow and neurological tolerance of ICA flow reversal for embolic protection. This was a study of patients undergoing transcervical carotid angioplasty and stenting. Neuroprotection was established by ICA flow reversal. All patients underwent preoperative cervical and cerebral noninvasive angiography with CTA or MRA and had at least one patent intracranial collateral. Mean carotid artery back pressure was measured. Neurological changes during carotid clamping and flow reversal were continuously monitored with electroencephalography (EEG). Thirty-seven patients with at least one patent intracranial collateral on brain imaging with CTA or MRA were included. Mean carotid artery back pressure was 58 mm Hg. All procedures were technically successful. No EEG changes were present with common carotid artery occlusion and ICA flow reversal. One patent intracranial collateral provides sufficient cerebral perfusion to perform carotid occlusion and flow reversal with absence of EEG changes. Continued progress in noninvasive imaging modalities is becoming increasingly helpful in our understanding of cerebral physiology and selection of patients for invasive carotid procedures.

Claudication distances and the Walking Impairment Questionnaire best describe the ambulatory limitations in patients with symptomatic peripheral arterial disease.

BACKGROUND: Claudication secondary to peripheral arterial disease leads to reduced mobility, limited physical functioning, and poor health outcomes. Disease severity can be assessed with quantitative clinical methods and qualitative self-perceived measures of quality of life. Limited data exist to document the degree to which quantitative and qualitative measures correlate. The current study provides data on the relationship between quantitative and qualitative measures of symptomatic peripheral arterial disease. METHOD: This descriptive case series was set in an academic vascular surgery unit and biomechanics laboratory. The subjects were symptomatic patients with peripheral arterial disease patients presenting with claudication. The quantitative evaluation outcome measures included measurement of ankle-brachial index, initial claudication distance, absolute claudication distance, and self-selected treadmill pace. Qualitative measurements included the Walking Impairment Questionnaire (WIQ) and the Medical Outcomes Study Short Form-36 (SF-36) Health Survey. Spearman rank correlations were performed to determine the relationship between each quantitative and qualitative measure and also between the WIQ and SF-36. RESULTS: Included were 48 patients (age, 62 +/- 9.6 years; weight, 83.0 +/- 15.4 kg) with claudication (ABI, 0.50 +/- 0.20). Of the four WIQ subscales, the ankle-brachial index correlated with distance (r = 0.29) and speed (r = 0.32); and initial claudication distance and absolute claudication distance correlated with pain (r = 0.40 and 0.43, respectively), distance (r = 0.35 and 0.41, respectively), and speed (r = 0.39 and 0.39 respectively). Of the eight SF-36 subscales, no correlation was found for the ankle-brachial index, initial claudication distance correlated with Bodily Pain (r = 0.46) and Social Functioning (r = 0.30), and absolute claudication time correlated with Physical Function (r = 0.31) and Energy (r = 0.30). The results of both questionnaires showed reduced functional status in claudicating patients. CONCLUSIONS: Initial and absolute claudication distances and WIQ pain, speed, and distance subscales are the measures that correlated the best with the ambulatory limitation of patients with symptomatic peripheral arterial disease. These results suggest the WIQ is the most specific questionnaire for documenting the qualitative deficits of the patient with claudication while providing strong relationships with the quantitative measures of arterial disease. Future studies of claudication patients should include both quantitative and qualitative assessments to adequately assess disease severity and functional status in peripheral arterial disease patients.

Inferior vena cava filter placement for pulmonary embolism risk reduction in super morbidly obese undergoing bariatric surgery.

BACKGROUND: Pulmonary embolism (PE) is a leading cause of mortality after bariatric surgery. We evaluated inferior vena cava (IVC) filter use for PE risk reduction in high-risk super morbidly obese bariatric surgery patients. METHODS: IVC filters were inserted according to the patient's risk factors, including immobility, previous deep venous thrombosis (DVT)/PE, venous stasis, and pulmonary compromise. All filters were placed concomitant to bariatric surgery and were placed through a right internal jugular vein access site. We analyzed the prospectively collected data from this cohort and evaluated the incidence of PE and complications. RESULTS: Since April 2003, 41 patients (12 men and 29 women) with a mean age of 47.3 +/- 10.0 years and body mass index of 64.2 +/- 12 kg/m2 (range 47-105) underwent IVC filter placement. These and all other patients underwent standard DVT/PE risk reduction measures. All IVC filter patients had one or more significant risk factors for thromboembolic events. No instances of PE were documented, although 1 patient experienced DVT, and no immediate or late complications related to filter placement occurred. One patient, with a body mass index of 105 kg/m2, died secondary to rhabdomyolysis after an extended procedure. The average filter placement time was 34.3 +/- 9 minutes. CONCLUSION: IVC filter placement for PE risk reduction is safe and feasible in the super morbidly obese. Our data have shown that the filters can be placed expeditiously and with minimal morbidity concomitant with bariatric surgery. In this limited series, IVC filter placement was associated with no PE. Additional studies are needed to confirm the efficacy of IVC filter placement for PE risk reduction and related mortality in the super morbidly obese.

Aneurysms of the carotid artery.

Carotid artery aneurysms are an uncommon but important problem. The available data suggests that, untreated, these aneurysms lead to neurologic symptoms from embolization. Pseudoaneurysms of the carotid artery result from injury or may be the long-term sequelae of a spontaneous carotid dissection. While open surgery has been the primary mode of treatment, these aneurysms are being treated more commonly with endovascular approaches. This trend is partly the result of the increasing experience with the endovascular treatment of carotid artery stenosis. The endovascular approach offers advantages in other situations where open access to the distal extent of the aneurysm is difficult or neck radiation leads to concerns about wound healing. This article outlines the etiology, new diagnostic modalities, and treatment of aneurysms of the carotid artery.

Endovascular repair of thoracic aortic pathology with custom-made devices.

BACKGROUND: Open repair of thoracic aortic aneurysms (TAAs) is fraught with high morbidity and mortality rates. The availability of endoprostheses for treating thoracic aortic pathology has not kept pace with those for treating abdominal aneurysms. Technical feasibility, durability, and safety of custom-made stent-grafts for the treatment of TAAs and dissections are evaluated. METHODS: From July 2002 to October 2004 there were 15 patients with TAAs, intramural hematoma, or dissections treated with custom-made endografts. Grafts were deployed after brief adenosine-induced cardiac arrest. Computed tomography scans were obtained 1 month postoperatively and every 6 months thereafter. The mean follow-up period was 15 months (range, 3-31 mo). RESULTS: The mean age of patients was 67 +/- 11 years (range, 47-81 y; 67% men, 33% women). Indications for repair included TAA (10), chronic type B dissection (3), penetrating ulcer (1), and acute dissection (1). Planned concomitant procedures included subclavian-carotid transposition (2) and aortosplenic bypass (2) to achieve adequate proximal or distal landing seal zones, respectively. The mean length of hospital stay was 8 days (range, 1-49 d). Immediate complications included 2 access-related events, 1 cerebellar infarction treated expectantly, and 1 death from a large hemispheric stroke. There were no cases of postoperative paralysis and on follow-up imaging no cases of endoleak, endograft migration, or stent fractures were found. No late deaths occurred caused by stent-graft repair or aneurysm-related causes. CONCLUSIONS: Endoluminal exclusion of thoracic aortic aneurysms and dissections can be achieved successfully using custom-made stent-grafts. The use of specially designed devices appears to be technically feasible and durable, with acceptable morbidity and mortality rates.