Assessment of Renal Injury in Patients Undergoing Elective EVAR Using Urinary Neutrophil Gelatin-Associated Lipocalin, Interleukin 18, and Retinol-Binding Protein

Acute kidney injury (AKI) is a recognized complication post-endovascular aneurysm repair (EVAR). Neutrophil gelatin-associated lipocalin (NGAL), interleukin 18 (IL-18), and retinol-binding protein are emerging urinary biomarkers that have shown promise in detecting subclinical and clinical renal impairment. In this study, we assessed changes in these urinary biomarkers as well as serum creatinine (SCr) in patients undergoing EVAR. Urine samples were collected prospectively at 5 time points for each recruited patient: pre-EVAR (baseline) and 6, 12, 24, and 48 hours after the procedure for serial assessment of urinary biomarkers. Serum creatinine was quantified preoperatively and at 24 and 48 hours postoperatively. Serial changes of urinary biomarkers and SCr were assessed. A significant increase in NGAL and IL-18 from baseline was observed ( P < .05), as early as 6 hours for NGAL. A significant rise in levels of NGAL and IL-18 precedes the significant rise in SCr. These findings highlight the potential of emerging urinary biomarkers in detecting early AKI following EVAR.

ClariVein® - Early results from a large single-centre series of mechanochemical endovenous ablation for varicose veins

Objectives

This study assessed the effectiveness and patient experience of the ClariVein® endovenous occlusion catheter for varicose veins from a large single-centre series in the UK.

Methods

A total of 300 patients (371 legs) underwent ClariVein® treatment for their varicose veins; 184 for great saphenous vein (GSV) incompetence, 62 bilateral GSV, 23 short saphenous vein (SSV), 6 bilateral SSV and 25 combined unilateral great saphenous vein and SSV. Patients were reviewed at an interval of two months post procedure and underwent Duplex ultrasound assessment. Postoperative complications were recorded along with patient satisfaction.

Results

All 393 procedures were completed successfully under local anaesthetic. Complete occlusion of the treated vein was initially achieved in all the patients, but at eight weeks’ follow-up, there was only partial obliteration in 13/393 (3.3%) veins. These were all successfully treated with ultrasound-guided foam sclerotherapy. Procedures were well tolerated with a mean pain score of 0.8 (0–10). No significant complications were reported.

Conclusions

ClariVein® can be used to ablate long and short saphenous varicose veins on a walk-in–walk-out basis. Bilateral procedures can be successfully performed, and these are well tolerated as can multiple veins in the same leg. Early results are promising but further evaluation and longer term follow-up are required.

ClariVein® - Early results from a large single-centre series of mechanochemical endovenous ablation for varicose veins

Objectives This study assessed the effectiveness and patient experience of the ClariVein® endovenous occlusion catheter for varicose veins from a large single-centre series in the UK. Methods A total of 300 patients (371 legs) underwent ClariVein® treatment for their varicose veins; 184 for great saphenous vein (GSV) incompetence, 62 bilateral GSV, 23 short saphenous vein (SSV), 6 bilateral SSV and 25 combined unilateral great saphenous vein and SSV. Patients were reviewed at an interval of two months post procedure and underwent Duplex ultrasound assessment. Postoperative complications were recorded along with patient satisfaction. Results All 393 procedures were completed successfully under local anaesthetic. Complete occlusion of the treated vein was initially achieved in all the patients, but at eight weeks' follow-up, there was only partial obliteration in 13/393 (3.3%) veins. These were all successfully treated with ultrasound-guided foam sclerotherapy. Procedures were well tolerated with a mean pain score of 0.8 (0-10). No significant complications were reported. Conclusions ClariVein® can be used to ablate long and short saphenous varicose veins on a walk-in-walk-out basis. Bilateral procedures can be successfully performed, and these are well tolerated as can multiple veins in the same leg. Early results are promising but further evaluation and longer term follow-up are required.

Use of ultrasmall superparamagnetic iron oxide particles for imaging carotid atherosclerosis

Based on the results of histopathological studies, inflammation within atherosclerotic tissue is now widely accepted as a key determinant of the disease process. Conventional imaging methods can highlight the location and degree of luminal stenosis but not the inflammatory activity of the plaque. Iron oxide-based MRI contrast media particularly ultrasmall supermagnetic particles of iron oxide have shown potential in assessing atheromatous plaque inflammation and in determining efficacy of antiatherosclerosis pharmacological treatments. In this paper, we review current data on the use of ultrasmall superparamagnetic iron oxides in atherosclerosis imaging with focus on ferumoxtran-10 and ferumoxytol. The basic chemistry, pharmacokinetics and dynamics, potential applications, limitations and future perspectives of these contrast media nanoparticles are discussed.

The open retrograde approach as an alternative for failed percutaneous access for difficult below the knee chronic total occlusions-A case series

Retrograde puncture via patent pedal vessels can be attempted in failed antegrade approach for infrapopliteal long chronic total occlusion. However in cases where the pedal vessels are unable to be visualized via duplex ultrasonography or fluoroscopy an open approach offers an additional option to a vascular surgeon for successful recanalization. Our case report highlights 3 cases where successful hybrid open retrograde approach was able to achieve recanalization of long chronic total occlusion.

Presentation of cases

The three cases in our series presented with critical limb ischaemia. All three cases had undergone duplex imaging of the affected arterial system. As the antegrade approach to cross the lesion failed a retrograde approach was attempted in all 3 cases. However when the usual modality of retrograde puncture via the use of ultrasound or fluoroscopy failed we proceeded with an open approach.

Discussion

Retrograde approach usually offers a better chance of successfully crossing a chronic total occlusion lesion. However puncturing a distal vessel successfully and traversing a catheter or guidewire across proves to be a challenge. An open approach offers an additional pathway for puncturing the target vessel when duplex imaging or fluoroscopic guidance fails.

Conclusion

Open approach is usually attempted as a last resort by many endovascular surgeons. However procedural time, contrast and radiation usage could have been cut short in cases where the distal target vessels pose a technical challenge for approach via a percutaneous method.

Remote preconditioning and major clinical complications following adult cardiovascular surgery: systematic review and meta-analysis

BACKGROUND

A number of 'proof-of-concept' trials suggest that remote ischaemic preconditioning (RIPC) reduces surrogate markers of end-organ injury in patients undergoing major cardiovascular surgery. To date, few studies have involved hard clinical outcomes as primary end-points.

METHODS

Randomised clinical trials of RIPC in major adult cardiovascular surgery were identified by a systematic review of electronic abstract databases, conference proceedings and article reference lists. Clinical end-points were extracted from trial reports. In addition, trial principal investigators provided unpublished clinical outcome data.

RESULTS

In total, 23 trials of RIPC in 2200 patients undergoing major adult cardiovascular surgery were identified. RIPC did not have a significant effect on clinical end-points (death, peri-operative myocardial infarction (MI), renal failure, stroke, mesenteric ischaemia, hospital or critical care length of stay).

CONCLUSION

Pooled data from pilot trials cannot confirm that RIPC has any significant effect on clinically relevant end-points. Heterogeneity in study inclusion and exclusion criteria and in the type of preconditioning stimulus limits the potential for extrapolation at present. An effort must be made to clarify the optimal preconditioning stimulus. Following this, large-scale trials in a range of patient populations are required to ascertain the role of this simple, cost-effective intervention in routine practice.

An infected enlarging abdominal aortic aneurysm after acute cholecystitis

INTRODUCTION

An abdominal aortic aneurysm (AAA) infection is rare and can be difficult to manage, with high morbidity and mortality. We present a patient who suffered an infected AAA after undergoing a laparoscopic cholecystectomy and discuss the surgical management options.

PRESENTATION OF CASE

A 69-year-old male presents with a rapidly enlarging AAA 4 weeks following laparoscopic cholecystectomy. He was managed with open debridement, washout and repair of the aneurysm, but suffered ongoing sequelae of Escherichia coli sepsis.

DISCUSSION

The options for surgical management of infected AAA include open, endovascular and combined approaches. Recent papers report successful use of endovascular repair of infected AAAs but this is an ongoing area of research.

CONCLUSION

Infection of an AAA is associated with high mortality and long-term morbidity and requires optimal treatment. Surgical options include open debridement and repair, endovascular aneurysm repair (EVAR) or a combined approach.

Mid-term cost-effectiveness analysis of open and endovascular repair for ruptured abdominal aortic aneurysm

BACKGROUND

Emergency endovascular repair (EVAR) for ruptured abdominal aortic aneurysm (rAAA) may have lower operative mortality rates than open surgical repair. Concerns remain that the early survival benefit after EVAR for rAAA may be offset by late reinterventions. The aim of this study was to compare reintervention rates and cost-effectiveness of EVAR and open repair for rAAA.

METHODS

A retrospective analysis was undertaken of patients with rAAA undergoing EVAR or open repair over 6 years. A health economic model developed for the cost-effectiveness of elective EVAR was used in the emergency setting.

RESULTS

Sixty-two patients (mean age 77·9 years) underwent EVAR and 85 (mean age 75·9 years) had open repair of rAAA. Median follow-up was 42 and 39 months respectively. There was no significant difference in 30-day mortality rates after EVAR and open repair (18 and 26 per cent respectively; P = 0·243). Reintervention rates were also similar (32 and 31 per cent; P = 0·701). The mean cost per patient was €26,725 for EVAR and €30,297 for open repair, and the cost per life-year gained was €7906 and €9933 respectively (P = 0·561). Open repair had greater initial costs: longer procedural times (217 versus 178·5 min; P < 0·001) and intensive care stay (5·0 versus 1·0 days; P = 0·015). Conversely, EVAR had greater reintervention (€156,939 versus €35,335; P = 0·001) and surveillance (P < 0·001) costs.

CONCLUSION

There was no significant difference in reintervention rates after EVAR or open repair for rAAA. EVAR was as cost-effective at mid-term follow-up. The increased procedural costs of open repair are not outweighed by greater surveillance and reintervention costs after EVAR.

Cardiopulmonary exercise testing provides a predictive tool for early and late outcomes in abdominal aortic aneurysm patients

Thompson AR, Peters N, Lovegrove RE et al. Cardiopulmonary exercise testing provides a predictive tool for early and late outcomes in abdominal aortic aneurysm patients. Ann R Coll Surg Engl 2011; 93: 474–481.

Sequential imaging of asymptomatic carotid atheroma using ultrasmall superparamagnetic iron oxide-enhanced magnetic resonance imaging: a feasibility study

BACKGROUND

Inflammation within atheromatous plaques is a known risk factor for plaque vulnerability. This can be detected in vivo on high-resolution magnetic resonance imaging (MRI) using ultrasmall superparamagnetic iron oxide (USPIO) contrast medium. The purpose of this study was to assess the feasibility of performing sequential USPIO studies over a 1-year period.

METHODS

Ten patients with moderate asymptomatic carotid stenosis underwent carotid MRI imaging both before and 36 hours after USPIO infusion at 0, 6, and 12 months. Images were manually segmented into quadrants, and the signal change per quadrant was calculated at these time points. A mixed repeated measures statistical model was used to determine signal change attributable to USPIO uptake over time.

RESULTS

All patients remained asymptomatic during the study. The mixed model revealed no statistical difference in USPIO uptake between the 3 time points. Intraclass correlation coefficients revealed a good agreement of quadrant signal pre-USPIO infusion between 0 and 6 months (0.70) and 0 and 12 months (0.70). Good agreement of quadrant signal after USPIO infusion was shown between 0 and 6 months (0.68) and moderate agreement was shown between 0 and 12 months (0.33).

CONCLUSIONS

USPIO-enhanced sequential MRI of atheromatous carotid plaques is clinically feasible. This may have important implications for future longitudinal studies involving pharmacologic intervention in large patient cohorts.

Local anaesthetic surgical treatment of severe objective pulsatile tinnitus: a useful technique

Objective pulsatile tinnitus is a rare condition with an often dramatic presentation. We present the case of a 70-year-old woman who presented with over two years' history of unilateral distressing objective pulsatile tinnitus. Carotid arteriography revealed a highly tortuous internal carotid artery. Computed tomography of the ipsilateral temporal bones showed a large jugular bulb. Internal jugular vein ligation under local anaesthetic yielded immediate resolution of her symptoms.

Efficacy of VBHOM to Predict Outcome Following Major Lower Limb Amputation

Purpose: This study tests an existing Vascular Biochemistry and Haematology Outcome Model (VBHOM) on independent data and presents further refinements to the model. Methods: Data from 306 patients who underwent lower limb amputation over a 4-year period were collated. Urea, creatinine, sodium, potassium, hemoglobin, white cell count, albumin, age, gender, mode-of-admission, and short-term mortality events were extracted from the database. This study tests an existing model and trains a new model for predicting mortality using forward stepwise logistic regression. Results: The existing model suggests a significant lack of fit (c-index = 0.665, P = .04). For the exception of gender and mode-of-admission, all predictor variables had significant univariate associations with short-term mortality ( P < .05). The refined model included age, sodium, potassium, creatinine, and albumin and had good discriminatory power (c-index = 0.8, no evidence of lack of fit, P = .616). Conclusions: Our simplified model had good predictive ability and suggests redundancy in input variables used by the existing models.

Ex vivo study of carotid endarterectomy specimens: quantitative relaxation times within atherosclerotic plaque tissues

PURPOSE

Previous studies reporting relaxation times within atherosclerotic plaque have typically used dedicated small-bore high-field systems and small sample sizes. This study reports quantitative T(1), T(2) and T(2) relaxation times within plaque tissue at 1.5 T using spatially co-matched histology to determine tissue constituents.

METHODS

Ten carotid endarterectomy specimens were removed from patients with advanced atherosclerosis. Imaging was performed on a 1.5-T whole-body scanner using a custom built 10-mm diameter receive-only solenoid coil. A protocol was defined to allow subsequent computation of T(1), T(2) and T(2) relaxation times using multi-flip angle spoiled gradient echo, multi-echo fast spin echo and multi-echo gradient echo sequences, respectively. The specimens were subsequently processed for histology and individually sectioned into 2-mm blocks to allow subsequent co-registration. Each imaging sequence was imported into in-house software and displayed alongside the digitized histology sections. Regions of interest were defined to demarcate fibrous cap, connective tissue and lipid/necrotic core at matched slice-locations. Relaxation times were calculated using Levenberg-Marquardt's least squares curve fitting algorithm. A linear-mixed effect model was applied to account for multiple measurements from the same patient and establish if there was a statistically significant difference between the plaque tissue constituents.

RESULTS

T(2) and T(2) relaxation times were statistically different between all plaque tissues (P=.026 and P=.002 respectively) [T(2): lipid/necrotic core was lower 47 ± 13.7 ms than connective tissue (67 ± 22.5 ms) and fibrous cap (60 ± 13.2 ms); T(2): fibrous cap was higher (48 ± 15.5 ms) than connective tissue (19 ± 10.6 ms) and lipid/necrotic core (24 ± 8.2 ms)]. T(1) relaxation times were not significantly different (P=.287) [T(1): Fibrous cap: 933 ± 271.9 ms; connective tissue (1002 ± 272.9 ms) and lipid/necrotic core (1044 ± 304.0 ms)]. We were unable to demarcate hemorrhage and calcium following histology processing.

CONCLUSIONS

This study demonstrates that there is a significant difference between qT(2) and qT(2) in plaque tissues types. Derivation of quantitative relaxation times shows promise for determining plaque tissue constituents.

Signal-to-noise ratio increase in carotid atheroma MRI: a comparison of 1.5 and 3 T

OBJECTIVES

This study reports quantitative comparisons of signal-to-noise ratio (SNR) at 1.5 and 3 T from images of carotid atheroma obtained using a multicontrast, cardiac-gated, blood-suppressed fast spin echo protocol.

METHODS

18 subjects, with carotid atherosclerosis (>30% stenosis) confirmed on ultrasound, were imaged on both 1.5 and 3 T systems using phased-array coils with matched hardware specifications. T(1) weighted (T(1)W), T(2) weighted (T(2)W) and proton density-weighted (PDW) images were acquired with identical scan times. Multiple slices were prescribed to encompass both the carotid bifurcation and the plaque. Image quality was quantified using the SNR and contrast-to-noise ratio (CNR). A phantom experiment was also performed to validate the SNR method and confirm the size of the improvement in SNR. Comparisons of the SNR values from the vessel wall with muscle and plaque/lumen CNR measurements were performed at a patient level. To account for the multiple comparisons a Bonferroni correction was applied.

RESULTS

One subject was excluded from the protocol owing to image quality and protocol failure. The mean improvement in SNR in plaque was 1.9, 2.1 and 2.1 in T(1)W, T(2)W and PDW images, respectively. All plaque SNR improvements were statistically significant at the p<0.05 level. The phantom experiment reported an improvement in SNR of 2.4 for PDW images.

CONCLUSIONS

Significant gains in SNR can be obtained for carotid atheroma imaging at 3 T compared with 1.5 T. There was also a trend towards increased CNR. However, this was not significant after the application of the Bonferroni correction.

Predicting outcome following colorectal cancer surgery using a colorectal biochemical and haematological outcome model (Colorectal BHOM)

AIM

To present a new biochemistry and haematology outcome model which uses a minimum dataset to model outcome following colorectal cancer surgery, a concept previously shown to be feasible with arterial operations.

METHOD

Predictive binary logistic regression models (a mortality and morbidity model) were developed for 704 patients who underwent colorectal cancer surgery over a 6-year period in one hospital. The variables measured included 30-day mortality and morbidity. Hosmer-Lemeshow goodness of fit statistics and frequency tables compared the predicted vs the reported number of deaths. Discrimination was quantified using the c-index.

RESULTS

There were 573 elective and 131 nonelective interventional cases. The overall mean predicted risk of death was 7.79% (50 patients). The actual number of reported deaths was also 50 patients (χ(2) = 1.331, df = 4, P-value = 0.856; no evidence of lack of fit). For the mortality model, the predictive c-index was = 0.810. The morbidity model had less discriminative power but there was no evidence of lack of fit (χ(2) = 4.198, df = 4, P-value = 0.380, c-index = 0.697).

CONCLUSIONS

The Colorectal Biochemistry and Haematology Outcome mortality model suggests good discrimination (c-index > 0.8) and uses only a minimal number of variables. However, it needs to be tested on independent datasets in different geographical locations.

Importance of specimen length during temporal artery biopsy

Background

Variations in surgical technique of temporal artery biopsy (TAB) performed for diagnosis of giant cell arteritis (GCA) may contribute to high false-negative rates. This was a retrospective analysis of a large database that explored potential associations between specimen length and diagnostic sensitivity of TAB.

Methods

Histopathological reports and medical records of patients who underwent TAB in six hospitals between 2004 and 2009 were reviewed.

Results

A total of 966 biopsies were analysed. The median postfixation specimen length was 1 (range 0·1–8·5) cm and 207 biopsies (21·4 per cent) were positive for GCA. Significant variation in prebiopsy erythrocyte sedimentation rate (ESR), arterial specimen length and positive results was noted amongst hospitals. Multivariable analysis revealed that patient age, ESR value and specimen length were independent predictors of GCA. Positive biopsies had significantly longer median specimen length compared with negative biopsies: 1·2 (range 0·3–8·5) versus 1·0 (0·2–8·0) cm respectively (P = 0·001). Receiver operating characteristic (ROC) analysis identified postfixation specimen length of at least 0·7 cm as the cut-off length with highest positive predictive value for a positive biopsy (area under ROC curve 0·574). Biopsies with specimen length of 0·7 cm or more had a significantly higher rate of positive results than smaller specimens (24·8 versus 12·9 per cent respectively; odds ratio 2·17, P = 0·001).

Conclusion

Specimen length and ESR were independent prognostic factors of a positive TAB result. A uniform referral practice and standard specimen length of approximately 1 cm could help eliminate discrepancies in the results of TAB.

Pre-emptive analgesia for chronic limb pain after amputation for peripheral vascular disease: a systematic review

BACKGROUND

Chronic stump and phantom limb pain after amputation for critical ischemia significantly affect patients' quality of life and pose challenging clinical problems. Pre-emptive analgesia attempts to prevent chronic postoperative pain by minimizing painful stimuli before and during surgery.

METHODS

This systematic literature review aimed to evaluate the evidence supporting the use of pre-emptive analgesia in minimizing the risk of chronic stump and phantom pain after lower limb amputation for critical ischemia of peripheral vascular disease.

RESULTS

A total of 11 studies have been retrieved. Five different types of analgesic drugs were evaluated (local anesthetics, opiates, N-methyl-D-aspartate receptor antagonists, a(2)-agonist, and gamma-aminobutyric acid analogues), administered separately or in combinations, through the oral, intravenous, epidural, or regional (perineural) route. The beneficial effect of combined bupivacaine, diamorphine, and clonidine in reducing the risk of phantom limb pain was supported by only one study (level 3 evidence). Epidural and perineural infusions containing local anesthetic ± opiates are effective in treating acute perioperative pain, although not without potentially serious complications. Most studies were characterized by high drop-out rates because of disease-associated mortality.

CONCLUSIONS

There is no robust evidence supporting the use of pre-emptive analgesia to minimize the risk of chronic pain after amputation for critical ischemia of peripheral vascular disease. The methods used are, however, effective in treating acute postoperative pain.

Neutrophil-Lymphocyte Ratio Predicts Medium-Term Survival Following Elective Major Vascular Surgery: A Cross-Sectional Study

Background: The systemic nature of atherosclerosis compromises medium-term survival following major vascular surgery. Neutrophil—lymphocyte ratio (NLR) is a simple index of systemic inflammatory burden which correlates with survival following percutaneous coronary intervention. Methods: Patients undergoing elective major vascular surgery in 2 tertiary vascular units were identified from prospectively maintained databases. Factors associated with 2-year mortality were assessed by univariate and multivariate analyses. Results: Over a 4-year period, 1021 patients underwent elective major vascular surgery (carotid endarterectomy, abdominal aortic aneurysm repair, lower limb revascularization). Two-year mortality was 11.2%. In multivariate analysis, preoperative NLR > 5 was independently associated with 2-year mortality (multivariate odds ratio [OR] 2.21; 95% confidence interval [CI] 1.22-4.01). Conclusion: Preoperative NLR identifies patients at increased risk of death within 2 years of major vascular surgery. This simple index may facilitate targeted preventive measures for high-risk patients.