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.

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.

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.

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.

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.

Matrix metalloproteinases 2 and 9 work in concert to produce aortic aneurysms.

Matrix metalloproteinases (MMPs) 9 and 2 are increased in human abdominal aortic aneurysm (AAA) tissue, but their precise role and potential interaction remain unclear. Experimental induction of aortic aneurysms in mice genetically deficient in these peptidases could provide new insight into AAA pathogenesis. Mice deficient in the expression of MMP-9 (MMP-9KO) or MMP-2 (MMP-2KO) and their corresponding wild-type background mice (WT) underwent AAA induction by abluminal application of calcium chloride (CaCl(2)). No aneurysm formation was observed at 10 weeks after treatment in either the MMP-9KO or the MMP-2KO mice, whereas the corresponding WT mice showed an average 74% and 52% increase in aortic diameter, respectively. Reinfusion of competent macrophages from the corresponding WT strains into knockout mice resulted in reconstitution of AAA in MMP-9KO but not MMP-2KO mice. These findings suggest that macrophage-derived MMP-9 and mesenchymal cell MMP-2 are both required and work in concert to produce AAA.

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.

MMP-12 has a role in abdominal aortic aneurysms in mice.

BACKGROUND: Matrix metalloproteinase (MMP)-12 levels are increased in the abdominal aortic aneurysm (AAA), implicating this protease in AAA pathogenesis. The purpose of this study was to assess the role of MMP-12 in aneurysm formation. METHODS: A murine aneurysm model was generated by periaortic application of 0.25 mol/L calcium chloride (CaCl 2 ) for 15 minutes. Aortic diameters were measured and compared before and 10 weeks after aneurysm induction. Aortic diameter changes for wild type (WT) and MMP-12 knockout (MMP-12 -/- ) mice were determined. MMP-12 production in mouse aorta was analyzed by casein zymography. MMP-2 and MMP-9 expressions were examined by gelatin zymography. Immunohistochemical study was used to measure macrophage infiltration into the aorta. RESULTS: There is an increase of 63 +/- 5% (mean +/- SEM) in aortic diameters of WT mice after CaCl 2 inductions, while MMP-12 -/- mice increased only 26 +/- 14%. Connective tissue staining of aortic sections from WT mice showed disruption and fragmentation of medial elastic fibers, while MMP-12 -/- mice showed only focal elastic lamellae breakdown. MMP-12 levels in WT mice were significantly increased after CaCl 2 treatment, whereas no MMP-12 was detected in MMP-12 -/- mice. There was no difference in the MMP-2 and MMP-9 productions between WT and MMP-12 -/- mice. Immunohistochemical analysis demonstrated that infiltrating macrophages in the aorta of MMP-12 -/- mice were significantly less than WT controls. CONCLUSIONS: MMP-12 deficiency attenuates aneurysm growth, possibly by decreasing macrophage recruitment.

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.

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.

Does carotid stenting measure up to endarterectomy? A vascular surgeon's experience.

HYPOTHESIS: Carotid angioplasty and stenting seems to have equal or better outcomes in high-risk patients than carotid endarterectomy. DESIGN: Single-center case-control study. SETTING: University hospital tertiary referral center. PATIENTS: Individuals (n = 53) undergoing elective carotid angioplasty and stenting for cervical carotid stenosis (n = 57) between April 2001 and October 2003. All patients were referred to and treated by the primary author (M.K.E.). RESULTS: Mean +/- SD age was 68.8 +/- 1.2 years (64% men [34] and 36% women [19]), and overall mean +/- SD rate of stenosis was 79% +/- 10%. Preprocedural neurologic symptoms were present in 42% of the group. Indications for treatment included prior neck surgery with irradiation (4), recurrent stenosis (19), and severe comorbidities (34). Duplex scanning 24 hours after stenting showed immediate mean percentage reductions in peaksystolic velocity and end diastolic velocity of 74% and 76%, respectively. After a 30-day follow-up period, there were no deaths and no major or minor strokes. One patient (1.7%) developed transient amaurosis fugax 12 hours after the procedure. Four patients (7.0%) experienced access-related complications. Intraoperative complications included 1 seizure (1.7%) and 1 asystolic arrest (1.7%), both treated successfully. During follow-up, 3 cases of re-stenosis (5.0%) occurred. One asymptomatic occlusion (1.7%) was detected at the 6-month follow-up visit. There have been no late carotid-related complications or deaths. CONCLUSIONS: Vascular surgeons possessing advanced catheter-based skills can safely perform carotid angioplasty and stenting and can achieve perioperative results comparable with carotid endarterectomy. Determination of the true efficacy and durability of carotid angioplasty and stenting as compared with endarterectomy awaits ongoing randomized national trials.

Overview of success of EVAR: progress to date.

Endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms has been challenged by a number of groups, and the shortcomings of this procedure have been documented in the scientific literature. However, patients and physicians continue to pursue this procedure as a viable means of treating abdominal aortic aneurysms. Both device evolution and advancement of technical skills have led to dramatic improvements in the outcomes of EVAR within the last decade. These improvements and accomplishments have also been chronicled in the literature. This review looks at the successes of EVAR, based on both US Food and Drug Administration trials and independent studies comparing conventional open repair and endovascular repair.

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.