Predictors of creatinine rise post-endovascular abdominal aortic aneurysm repair

Accuracy of registration techniques and vascular imaging modalities in fusion imaging for aortic endovascular interventions: a phantom study

Background

This study aimed to assess the error of different registration techniques and imaging modalities for fusion imaging of the aorta in a standardized setting using a anthropomorphic body phantom.

Materials and methods

A phantom with the 3D printed vasculature of a patient suffering from an infrarenal aortic aneurysm was constructed. Pulsatile flow was generated via an external pump. CTA/MRA of the phantom was performed, and a virtual 3D vascular model was computed. Subsequently, fusion imaging was performed employing 3D-3D and 2D-3D registration techniques. Accuracy of the registration was evaluated from 7 right/left anterior oblique c-arm angulations using the agreement of centerlines and landmarks between the phantom vessels and the virtual 3D virtual vascular model. Differences between imaging modalities were assessed in a head-to-head comparison based on centerline deviation. Statistics included the comparison of means ± standard deviations, student’s t-test, Bland-Altman analysis, and intraclass correlation coefficient for intra- and inter-reader analysis.

Results

3D-3D registration was superior to 2D-3D registration, with the highest mean centerline deviation being 1.67 ± 0.24 mm compared to 4.47 ± 0.92 mm. The highest absolute deviation was 3.25 mm for 3D-3D and 6.25 mm for 2D-3D registration. Differences for all angulations between registration techniques reached statistical significance. A decrease in registration accuracy was observed for c-arm angulations beyond 30° right anterior oblique/left anterior oblique. All landmarks (100%) were correctly positioned using 3D-3D registration compared to 81% using 2D-3D registration. Differences in accuracy between CT and MRI were acceptably small. Intra- and inter-reader reliability was excellent.

Conclusion

In the realm of registration techniques, the 3D-3D method proved more accurate than did the 2D-3D method. Based on our data, the use of 2D-3D registration for interventions with high registration quality requirements (e.g., fenestrated aortic repair procedures) cannot be fully recommended. Regarding imaging modalities, CTA and MRA can be used equivalently.

Novel diagnostic and imaging techniques in endovascular iliac artery procedures

INTRODUCTION

Endovascular revascularization has become the preferred treatment for most patients with iliac artery obstructions, with a high rate of clinical and technical success.

AREAS COVERED

This review will describe novel developments in the diagnosis and treatment of iliac artery obstructions including the augmentation of preprocedural imaging with advanced flow models, image fusion techniques, and state-of-the-art device-tracking capabilities.

EXPERT OPINION

The combination of these developments will change the endovascular field within the next 5 years, allowing targeted iliac treatment without the need for radiographic imaging or iodinated contrast media.

Perioperative care of geriatric patients

The older population is expected to nearly double across the globe by 2050, and the baby boom cohort is expected to represent at least 20% of the US population by 2030. Geriatric patients will increasingly utilize the health-care system, and therefore surgical and perioperative care must be tailored to this sensitive group given the increased risk for perioperative complications. The literature was reviewed to highlight fundamental components of the preoperative evaluation as well as cardiac, pulmonary, and renal complications. Frailty is a multidimensional process that can lead to the physiologic effects of aging and estimates the risk of perioperative morbidity and mortality better than chronologic age alone. Health-care providers should assess a geriatric patient's cognitive status, decision-making capacity, frailty, advance care planning, medications, and anesthetic approach in a multidisciplinary fashion to ensure optimal care. The risks of postoperative cardiac, pulmonary, and renal complications should be evaluated and optimized preoperatively to reduce the potential for adverse outcomes.

Perioperative Acute Kidney Injury: Risk Factors and Predictive Strategies

Acute kidney injury (AKI) is a common complication in surgical patients and is associated with increases in mortality, an increased risk for chronic kidney disease and hemodialysis after discharge, and increased cost. Better understanding of the risk factors that contribute to perioperative AKI has led to improved AKI prediction and will eventually lead to improved prevention of AKI, mitigation of injury when AKI occurs, and enhanced recovery in patients who sustain AKI. The development of advanced clinical prediction scores for AKI, new imaging techniques, and novel biomarkers for early detection of AKI provides new tools toward these ends.

Acute Kidney Injury in the Surgical Patient

Perioperative acute kidney injury (AKI) is a common, morbid, and costly surgical complication. Current efforts to understand and manage AKI in surgical patients focus on prevention, mitigation of further injury when AKI has occurred, treatment of associated conditions, and facilitation of renal recovery. Lesser severity AKI is now understood to be much more common, and more morbid, than was previously thought. The ability to detect AKI within hours of onset would be helpful in protecting the kidney and in preserving renal function, and several imaging and biomarker modalities are currently being evaluated.

Mannitol and renal dysfunction after endovascular aortic aneurysm repair procedures: a randomized trial

OBJECTIVE

Endovascular aortic aneurysm repair (EVAR) may result in deterioration of renal function. Mannitol has renovascular and antioxidant properties that could prove beneficial in this respect.

DESIGN

A randomized prospective study.

SETTING

Attikon University Hospital, single institution.

PARTICIPANTS

Eighty-six patients undergoing elective EVAR under regional anesthesia.

METHODS

Patients received hydration alone (controls) or hydration plus mannitol (0.5 g/kg).

MEASUREMENTS AND MAIN RESULTS

Creatinine, serum cystatin-C, urine neutrophil-gelatinase-associated lipocalin (NGAL), albuminuria and serum urea were measured 24 hours and 72 hours after the procedure (baseline NGAL was measured in 19 randomly selected patients). Serum creatinine also was measured at the followup of the patients. Serum creatinine and cystatin-C were lower in the mannitol group at 24 hours postoperatively (creatinine, mannitol [n=43]; 1.07±0.26 [CI95%: 0.99-1.15] v controls [n=43]; 1.20±0.30 [CI95%: 1.11-1.30]), but not at 72 hours (creatinine, mannitol [n=43]; 1.13±0.29 [CI95%: 1.04-1.22] v controls [n=43]; 1.26±0.41 [CI95% 1.15-1.38]). Urine NGAL increased substantially at 24 hours without differences between groups. At followup (controls: 13±7 months; mannitol: 12±7 months), there were no differences between creatinine or creatinine clearance (creatinine: controls [n=28]; 1.15±0.39 [CI95% 1.02-1.29] v mannitol [n=23]; 1.05±0.27 [CI95%: 0.95-1.17]). The overall changes of creatinine and creatinine clearance with time were significant in controls but not in the mannitol group. The classification according to the RIFLE criteria yielded 4 patients at risk for renal injury and 2 with renal injury in the control group and 6 patients at risk with no patients with injury in the mannitol group, but the difference of renal dysfunction between the 2 groups was not statistically significant.

CONCLUSIONS

Mannitol plus hydration during EVAR provides a small but significant benefit for renal function. Future preventive protocols aiming at greater restoration of renal function after EVAR could include mannitol as a useful component.

Anesthetic technique and acute kidney injury in endovascular abdominal aortic aneurysm repair

OBJECTIVE

Prior studies suggest that general anesthesia (GA) is associated with worse cardiopulmonary outcomes after endovascular abdominal aortic aneurysm repair (EVAR). Patients undergoing EVAR are at a high risk of developing perioperative acute kidney injury (AKI), and the relationship between anesthetic technique and AKI in these patients is not well-characterized. The authors sought to determine if anesthetic technique affected the risk of AKI in patients undergoing EVAR.

DESIGN

Retrospective, observational cohort study analyzed using a multivariate logistic regression model to assess the effects of anesthetic technique on renal outcome.

SETTING

Multiple institutions, mainly in North America.

PARTICIPANTS

Patients in the American College of Surgeons National Surgical Quality Improvement Program from 2005-2010 undergoing EVAR.

INTERVENTIONS

The authors investigated the association between anesthetic techniques, comparing GA to alternative (non-GA) techniques, and AKI.

MEASUREMENTS AND MAIN RESULTS

AKI was defined as an increase in the creatinine level of>2 mg/dL and/or dialysis. Of 13,026 patients, 84.4% underwent GA and 15.6% underwent non-GA techniques. AKI developed in 2.0% of the GA group and 1.4% of the non-GA group (unadjusted odds ratio [OR] 1.43, p = 0.075; adjusted OR [aOR] 1.00, p = 0.99). Risk factors for AKI include ASA class, ruptured aneurysm, preoperative renal dysfunction, symptomatic cardiovascular disease, and perioperative blood transfusion.

CONCLUSIONS

Anesthetic technique is not independently associated with the risk of AKI in patients undergoing EVAR.