Endovascular Management of Abdominal Aortic Aneurysms: the Year in Review

Experimental Study of Collateral Patency following Overlapped Multilayer Flow Modulators Deployment

Decades after its introduction, endovascular aneurysm repair remains a challenging procedure with risks of collateral patency failure. Here, we investigate the ability of a porous stent, the Multilayer Flow Modulator (MFM), to maintain renal perfusion after a single or overlapping case. Silicone models representing an ideal infrarenal AAA geometry were used to analyze and compare three cases (control, single MFM and two overlapped MFMs). Micro-computed tomography was used to image the deployed MFM devices geometry and evaluate pore size and density along with porosity in both two (planimetric) and three dimensions (gravimetric). Laser particle image velocimetry (PIV) experiments were performed to image velocity and vorticity fields at the aorta-renal bifurcation. Flow experiments revealed renal arteries perfusion preservation in both single and overlapped cases. Microstructure analysis revealed an uneven distribution of wires in the MFM devices leading to local change in planimetric porosity and pore size. Overlap of a second MFM device led to a significant decrease in those 2D metrics but did not affect the gravimetric porosity and the branch perfusion. This first microstructure evaluation of MFM device combined with flow experiments revealed the ability of the device to preserve collateral flow thanks to a highly porous microstructure.

Renal Artery Catheterization for Microcapsules' Targeted Delivery to the Mouse Kidney

The problem of reducing the side effects associated with drug distribution throughout the body in the treatment of various kidney diseases can be solved by effective targeted drug delivery. The method described herein involves injection of a drug encapsulated in polyelectrolyte capsules to achieve prolonged local release and long-term capillary retention of several hours while these capsules are administered via the renal artery. The proposed method does not imply disruption (puncture) of the renal artery or aorta and is suitable for long-term chronic experiments on mice. In this study, we compared how capsule size and dosage affect the target kidney blood flow. It has been established that an increase in the diameter of microcapsules by 29% (from 3.1 to 4.0 μm) requires a decrease in their concentration by at least 50% with the same suspension volume. The photoacoustic method, along with laser speckle contrast imaging, was shown to be useful for monitoring blood flow and selecting a safe dose. Capsules contribute to a longer retention of a macromolecular substance in the target kidney compared to its free form due to mechanical retention in capillaries and slow impregnation into surrounding tissues during the first 1-3 h, which was shown by fluorescence tomography and microscopy. At the same time, the ability of capillaries to perform almost complete "self-cleaning" from capsular shells during the first 12 h leads to the preservation of organ tissues in a normal state. The proposed strategy, which combines endovascular surgery and the injection of polymer microcapsules containing the active substance, can be successfully used to treat a wide range of nephropathies.

Abdominal compartment syndrome after r-EVAR: a systematic review with meta-analysis on incidence and mortality

INTRODUCTION

Endovascular aneurysm repair for ruptured abdominal aortic aneurysms (r-EVAR) sometimes complicates with abdominal compartment syndrome (ACS) due to extensive retroperitoneal hematoma, with significant prognostic implications. This systematic review aimed to analyze the incidence of the syndrome and assess the impact of ACS on mortality. Mortality after decompressive laparotomy was also assessed.

EVIDENCE ACQUISITION

Two databases were searched: Medline and Web of Science. The search was conducted through October 2019. The titles and abstracts of the retrieved articles were independently reviewed. All studies reporting on the ACS incidence after r-EVAR were initially included. From each study, eligibility was determined and descriptive, methodological, and outcome data was extracted. The incidence was calculated with summary proportion. Odds ratio was used to compare the mortality rate. Meta-analysis was performed with fixed effect model when calculating the ACS incidence in r-EVAR patients and when assessing the impacts of ACS and DL in the mortality rate.

EVIDENCE SYNTHESIS

A total of 46 studies were included, with a cumulative cohort of 3064 patients. Two hundred and fifty-two (8.2%) patients developed ACS. The ACS pooled incidence was 9% with a 95% confidence interval of [0.08; 0.11]. Among the 46 included studies, 19 studies reported data on the mortality rate, corresponding to 1825 of the 3064 patients. Of these, 169 (9.3%) had developed ACS and 94 (55.6%) of them died by multi organ failure. Among the 1656 patients without ACS, 328 died (19.8%). The mortality odds ratio meta-analysis was 6.25 with a 95% confidence interval of [4.44, 8.80]. Decompressive laparotomy was performed in 41 patients, decreasing mortality in 47%.

CONCLUSIONS

ACS affects approximately 9% of patients submitted to r-EVAR, and significantly increases perioperative mortality. Close postoperative surveillance to clinical signs of ACS is vital in these patients.

Post-Traumatic Ostial Avulsion of a Polar Inferior Renal Artery Treated by Endovascular Covered Aortic Stenting

Renovascular traumas are rare in abdominal blunt traumas, especially those involving complete avulsion of a renal artery. Their management poses a dilemma between blood flow preservation and the risks of bleeding. We present the case of a rare variant of renovascular injury, with a post traumatic ostial avulsion of a polar inferior renal artery, successfully treated percutaneously by endovascular aortic covered stenting under c-arm cone-beam computed tomography guiding.

Mortality, Length of Stay, and Cost Implications of Procedural Bleeding After Percutaneous Interventions Using Large-Bore Catheters

Importance

Bleeding complications after percutaneous transcatheter interventions that used large-bore catheters are frequent and associated with high mortality and morbidity.

Objective

To describe the incidence of bleeding complications among patients undergoing contemporary endovascular interventions involving large-bore catheters and its association with in-hospital mortality, length of stay, and health care cost.

Design, Setting, and Participants

This retrospective cohort study analyzed all 17 672 patients from the Healthcare Cost and Utilization Project's National Inpatient Sample database who were recorded as having undergone a transcatheter aortic valve replacement (n = 3223), an endovascular aneurysm repair (n = 12 633), or a percutaneous left ventricular assist device implant (n = 1816) between January 1, 2012, and December 31, 2013. Bleeding complication was defined as any transfusion, any hemorrhage or hematoma, or the need for percutaneous or surgical intervention to control the bleeding event. Health care costs were determined by multiplying the total charge for each visit by the cost to charge ratios reported for each hospital code in the database. Data were collected from the database on April 29, 2016.

Main Outcomes and Measures

Adjusted association between bleeding complications and mortality was determined by multivariable logistic regression. Length of stay and total health care costs were compared using multivariable linear regression between patients who did and patients who did not have bleeding complications.

Results

Bleeding complications occurred in 3128 patients (17.7%) (1984 men and 1144 women, with a mean [SD] age of 75.6 [11.9] years). Bleeding was associated with higher mortality (adjusted odds ratio, 2.70; 95% CI, 2.27-3.22; P < .001) and longer hospital stay (adjusted multiplicative difference, 2.14; 95% CI, 2.06-2.16; P < .001). Median (interquartile range) total health care costs were $48 663 ($32 620-$71 547) for patients with bleeding complications compared with $29 968 ($21 924-$43 287) for patients without a bleeding complication (adjusted multiplicative difference, 1.55; 95% CI, 1.52-1.59; P < .001).

Conclusions and Relevance

Periprocedural bleeding was common among patients who underwent transcatheter intervention using large-bore catheters and was associated with a statistically significant increase in mortality, length of stay, and cost.

3D Printed Abdominal Aortic Aneurysm Phantom for Image Guided Surgical Planning with a Patient Specific Fenestrated Endovascular Graft System

Following new trends in precision medicine, Juxatarenal Abdominal Aortic Aneurysm (JAAA) treatment has been enabled by using patient-specific fenestrated endovascular grafts. The X-ray guided procedure requires precise orientation of multiple modular endografts within the arteries confirmed via radiopaque markers. Patient-specific 3D printed phantoms could familiarize physicians with complex procedures and new devices in a risk-free simulation environment to avoid periprocedural complications and improve training. Using the Vascular Modeling Toolkit (VMTK), 3D Data from a CTA imaging of a patient scheduled for Fenestrated EndoVascular Aortic Repair (FEVAR) was segmented to isolate the aortic lumen, thrombus, and calcifications. A stereolithographic mesh (STL) was generated and then modified in Autodesk MeshMixer for fabrication via a Stratasys Eden 260 printer in a flexible photopolymer to simulate arterial compliance. Fluoroscopic guided simulation of the patient-specific FEVAR procedure was performed by interventionists using all demonstration endografts and accessory devices. Analysis compared treatment strategy between the planned procedure, the simulation procedure, and the patient procedure using a derived scoring scheme.

RESULTS

With training on the patient-specific 3D printed AAA phantom, the clinical team optimized their procedural strategy. Anatomical landmarks and all devices were visible under x-ray during the simulation mimicking the clinical environment. The actual patient procedure went without complications.

CONCLUSIONS

With advances in 3D printing, fabrication of patient specific AAA phantoms is possible. Simulation with 3D printed phantoms shows potential to inform clinical interventional procedures in addition to CTA diagnostic imaging.