Graft durability and fatigue after in situ fenestration of endovascular stent grafts using radiofrequency puncture and balloon dilatation.

OBJECTIVES: In situ fenestration of endovascular stent grafts is a technique that is becoming more common, as it has the advantages of decreased cost, increased availability, and more anatomic configuration than other methods of branch revascularization. However, a significant concern is the short- and long-term durability of the stent graft fabric during and after fenestration. METHODS: This study utilizes the textiles analysis techniques of macro- and microscopic imaging, tear strength testing, burst strength testing, and accelerated cyclic fatigue testing on the fabrics of the Cook Zenith, Medtronic Talent, and Medtronic Endurant stent grafts (three polyester grafts), as well as two different expanded polytetrafluoroethylene (ePTFE) membranes. Specimens were punctured using radiofrequency, and serially dilated with angioplasty balloons (3, 5, and 7 mm). For each type of fabric, three groups were analyzed: control, radiofrequency (RF) puncture only, and balloon dilated. RESULTS: A total of 110 specimens were analyzed, with 80 of them having been fenestrated. The Zenith fabric had the greatest strength after fenestration, but was limited by the inability to fully dilate the fenestration with the conventional balloons, which only achieved 26-29% of their nominal balloon diameter. While the Talent and Endurant grafts could be dilated with balloons, the orifices were markedly elliptical not circular. After accelerated fatigue testing, there was an increase in the size of fenestrations of the Talent fabric. There was no increase in fenestration size for the Endurant fabric, Zenith fabric, or the ePTFE fabrics, after fatigue testing. CONCLUSIONS: While the Zenith fabric was the strongest both before and after fenestration, it requires further study with cutting balloons to achieve full-sized fenestrations. All fenestrations remained stable during fatigue testing except for the Talent fabric. This study serves as the baseline for future studies that will include stent grafts, branch stents, and cutting balloons.

Soft tissue vascular tumor-like lesions in adults: imaging and pathological analysis pitfalls per ISSVA classification.

OBJECTIVES: To compare the magnetic resonance imaging (MRI) and Doppler ultrasound (DUS) findings with the pathological findings of soft tissue vascular tumors (STVTs) according to the 2018 ISSVA (International Society for the Study of Vascular Anomalies) classification to differentiate vascular tumors from vascular malformations. METHODS: This retrospective study included patients with STVTs who underwent contrast-enhanced MRI and pathological analysis at our hospital between 2010 and 2020. The presumptive diagnosis based on the on-site imaging and histological analysis was compared with imaging and histological analysis conducted off-site utilizing the ISSVA criteria. RESULTS: This study included 31 patients with 31 vascular tumors located in the head and neck (n = 3), trunk (n = 2), and extremities (n = 26). The off-site pathological analysis confirmed benign vascular tumors in 54.8% of cases (non-involuting congenital hemangioma: 35.5%; epithelioid hemangioma: 13%; pyogenic granuloma: 3%; and spindle cell hemangioma: 3%). Based on the off-site histological analysis, 25.8% were reclassified as having a vascular malformation whereas three had other benign lesions. Only phleboliths were associated with a vascular malformation (p = 0.03). The concordance between off-site MRI and pathological findings was fair (k = 0.3902 (0.0531-0.7274)), whereas that between on-site and off-site pathological analyses was poor (k = -0.0949 (-0.4661 to 0.2763)). CONCLUSION: Benign vascular tumors have non-specific imaging features on imaging with some overlap with atypical vascular malformations. Therefore, histological analysis is recommended. Imaging and pathological analyses should be performed in accordance with the ISSVA classification to minimize inter-observer discrepancies. CRITICAL RELEVANCE STATEMENT: Imaging features of benign vascular tumors on MRI are non-specific, leading to discrepancies with pathological findings and potential overlap with atypical vascular malformations. Imaging and histological analyses should be performed in accordance with ISSVA guidelines to improve patient management. KEY POINTS: The imaging features of benign vascular tumors are non-specific. Histological analysis is recommended for soft tissue vascular tumors in adults. Analyses of soft tissue vascular tumors should be performed in accordance with ISSVA guidelines.

[Interventional angioradiology as a solution for microsurgical flap failure]. / La radioangiologie interventionnelle comme solution de sauvetage en microchirurgie.

The microsurgical failure rate is almost constant for several decades. We present two case reports describing a novel method of free flap salvage using angioradiological techniques. Our first case shows the potential utility of in situ thrombolysis, our second case describes the first use of stents within a microsurgical anastomosis. In boths cases, the flap would have been lost immediately, because flap revisions failed. Thus, before abandoning on a flap, one could perform a simple angiography to evaluate further angioradiological salvage possibilities and hereby contribute to improve long term microsurgical failure rate.

In Vivo Feasibility of Arterial Embolization with Permanent and Absorbable Suture: The FAIR-Embo Concept.

PURPOSE: Arterial embolization has been shown to be effective and safe for the management of bleeding, especially for postpartum and pelvic traumatic bleeding. We propose to evaluate the proof of concept of feasibility and effectiveness of arterial embolization with absorbable and non-absorbable sutures in a porcine model. MATERIALS AND METHODS: In the acute setting (n = 1), several different arteries (mesenteric, splenic, pharyngeal, kidney) were embolized using non-absorbable sutures (NAS): Mersutures™ braided sutures (polyethylene terephthalate). In the chronic setting (n = 3), only lower pole renal arteries were embolized. On the right side, NAS was used, whereas on the left side embolization was realized with absorbable suture (AS): Vicryl® braided suture (polyglactin 910). The chronic group was followed for 3 months. The pigs received contrast-enhanced CT the day before embolization (D-1), after the embolization (D0), at 1 month and 3 months after embolization (M1 and M3); digital subtraction angiography (DSA) was done at D0 and M3 and histological analysis at M3. RESULTS: All vascular targets were effectively embolized without any pre- or postoperative complications. Both DSAs and CTs at M3 showed a 100% recanalization rate for the AS embolization and a partial reversal rate for the NAS embolization. A renal hypotrophy in the embolized region was observed during both the M1 and M3 scans for both sutures (AS and NAS) with a clear hypotrophy for the NAS embolized kidney. CONCLUSION: Embolization by AS and NAS (FAIR-Embo) is a feasible and effective treatment which opens up the possibility of global use of this inexpensive and widely available embolization agent.

Incidental findings in CT imaging of coronary artery bypass grafts: results from a Canadian multicenter prospective cohort.

OBJECTIVE: To assess the prevalence and clinical significance of incidental findings identified during computed tomography imaging of coronary artery bypass grafts. RESULTS: This prospective study includes 144 patients undergoing coronary graft patency assessment using computed tomography. Incidental findings were classified as significant if they were considered to need an immediate action or treatment, short-term work-up or follow-up, or minor. A total of 211 incidental findings were present in 109 (75.7%) patients. Seventy-one incidental findings (33.6%) were cardiac and 140 (66.4%) were extracardiac. Most common cardiac incidental findings were atrial dilatation [39 patients, 48 incidental findings (67.6%)] and aortic valve calcifications (7 patients, 9.9%). Among the 140 extracardiac incidental findings, the most common were lung nodules (51 patients, 54 nodules, 38.6%), and emphysema (21 patients, 15%). Thirty-six (25.7%) extracardiac incidental findings were significant and notably, 23 (63.9%) were lung nodules. Follow-up was recommended in 37 cases, among which all patients with significant lung nodules (23 patients, 62.2%). In conclusion, most common computed tomography incidental findings in patients with coronary grafts were lung nodules and emphysema.

Multicenter evaluation of a self-expanding carotid stent system with distal protection in the treatment of carotid stenosis.

PURPOSE: Carotid artery stent placement may be limited by the embolization of atheromatous material. We evaluated the safety and feasibility of the Medtronic Self-Expanding Carotid Stent (Exponent) in combination with the Medtronic Interceptor Carotid Filter System for the treatment of carotid stenosis among patients at high risk for carotid endarterectomy. METHODS: Patients at high risk for carotid endarterectomy but amenable to percutaneous treatment with stent placement were enrolled. Clinical follow-up was performed at 30 days and 6 and 12 months postprocedure. The National Institutes of Health Stroke Scale was assessed before and within 3 days postprocedure and at 30 days and 6 months postprocedure. Angiography was performed pre- and postprocedure, and carotid duplex scans were performed at baseline and at 30 days and 6 months. RESULTS: Fifty-two carotid procedures were performed in 51 patients (mean age, 69 years; 84% of patients were men). The major adverse event (MAE) rate (death, stroke, and myocardial infarction [MI]) at 30 days was 5.9%: 2 strokes and a single death from periprocedural MI. MAE rates after 6 and 12 months were 5.9% and 11.8%, respectively. The delivery success rate was 94.2% (49/52) for the Interceptor Filter System and 95.9% (47/49) for the Exponent Stent. The mean diameter stenosis of the target lesion was reduced from 62.4% preprocedure to 21.2% postprocedure. CONCLUSION: High delivery success rates were achieved with a low rate of MAE (death, stroke, or MI) in a high-risk population. Treatment of carotid artery disease with the Exponent Carotid Stent combined with distal protection from the Interceptor Filter System is effective and safe.

Study of non stationary mode flow of an abdominal aortic aneurysm.

INTRODUCTION: Abdominal aortic aneurysm rupture is 95% lethal. Numerical simulation of Navier-Stokes equations allows seeing complex flow phenomenon in laminar state. METHOD: In this study, we work on a model using the finite element method with an actual 3D geometry. This geometry is from a point cloud obtained by a tomodensitometry scan of a typical patient. We consider rigid wall, homogeneous and Newtonian fluid. We impose four pulsative waveforms as entrance condition: two rest waveforms, two exercise waveforms. The four aver-age Reynolds numbers are 353 and 363 for the rest waveforms and 1058 and 1388 for the exercise waveforms. For the systolic peaks, the Reynolds numbers are 1639 and 1917 for the rest waveforms and 2800 and 2497 for the exercise waveforms. RESULTS: RESULTS show that during the systolic acceleration, vortices issued from the previous pulsation are pushed out and the flow reattached on the wall. During the systolic deceleration, a main vortex appears in the upper part of the aneurysm; it grows and moves to the center. During the diastole, the vortex sustains itself until the next pulsation for the exercise conditions. For the rest conditions, imposed oscillations during the diastole lead to secondary vortices. Pressure stays relatively constant in the aneurysm following the entrance conditions. DISCUSSION: These results on the flow and pressure repartition agreed with those found in the literature (1-6) validating in a first time our model. The next step of the study is the wall shear stress data exploitation.

Radionuclide captopril renography in postpartum renal artery aneurysms.

We report the case of a young woman with three left renal artery aneurysms, diagnosed immediately postpartum, associated with a de novo high blood pressure. To assess anatomical and functional characteristics of renal artery aneurysms, renal angiogram, MRI, intravenous pyelography, ultrasonography and radionuclide renography were performed. Two patent saccular renal artery aneurysms were demonstrated in the left kidney by renal angiogram. A larger, thrombosed aneurysm was also depicted on the left side on ultrasonography, MRI and renal angiogram. The larger aneurysm was responsible for renovascular disease of the middle third of the kidney, as demonstrated by captopril and baseline radionuclide renographic studies. It also impeded drainage of the lower pyelocalyceal group, without obstructing it, as shown by concomitant furosemide (Lasix) evaluations.

Comparison of early and delayed scintigraphy with 99mTc-apcitide and correlation with contrast-enhanced venography in detection of acute deep vein thrombosis.

UNLABELLED: Preliminary studies with 99mTc-apcitide (99mTc-P280), a synthetic peptide that binds to glycoprotein IIb/IIIa receptors expressed on activated platelets, have shown promising results in the detection of acute deep vein thrombosis (ADVT). The purpose of this study was to compare the diagnostic value of early and delayed imaging with 99mTc-apcitide in patients with suspected ADVT, using contrast-enhanced venography as the gold standard. METHODS: Thirty-nine patients (17 women, 22 men; mean age 59 y) with signs or symptoms suggestive of ADVT (within 10 d of onset) and scheduled for contrast-enhanced venography were prospectively studied. The patients were injected with approximately 740 MBq (20 mCi) 99mTc-apcitide within 36 h of contrast-enhanced venography. Both anterior and posterior planar images (8-10 min/view) of the lower extremities using a dual-head gamma camera were obtained at 10, 60 and 120 min after the injection of 99mTc-apcitide. The three sets of images initially were interpreted randomly and separately by three experienced observers unaware of the clinical history, the site of ADVT and results of contrast-enhanced venography. All images from the three sets for a given patient were then analyzed together during a second session. Conventional contrast-enhanced venography was performed on 31 patients before 99mTc-apcitide scintigraphy and in the remaining 8 patients after 99mTc-apcitide scintigraphy. 99mTc-apcitide findings were considered positive forADVT when a focus of increased uptake was found to correspond to the location of a deep vein. Disagreements were resolved by consensus. RESULTS: Twenty-two patients had ADVT observed on contrast-enhanced venography, whereas 17 had normal findings. Six cases of ADVT were infrapopliteal. One patient did not complete the third set of images with 99mTc-apcitide. The sensitivity of 99mTc-apcitide in detecting ADVT was 63.6% (14/22), 68.2% (15/22), 76.2% (16/21) and 86.4% (19/22) for images obtained at 10, 60 and 120 min and for the three sets analyzed together, respectively. The specificity was 82.4% (14/17), 76.5% (13/17), 88.2% (15/17) and 88.2% (15/17) for images obtained at 10, 60 and 120 min and for the three sets of images together, respectively. CONCLUSION: Although the set of 99mTc-apcitide images obtained 120 min after injection showed good overall diagnostic accuracy, the combination of at least two sets of images provided the highest accuracy in detecting ADVT.

Catheter-assisted totally thoracoscopic coronary artery bypass grafting: a feasibility study.

BACKGROUND: The purpose of this study is to examine the feasibility of performing totally thoracoscopic internal mammary-to-coronary artery bypass grafting with the assistance of radiologically guided catheter intervention. METHODS: Fourteen dogs were subjected to mobilization of the internal mammary artery and anastomosis of it to the left anterior descending coronary artery over an angiographic catheter inserted into the internal mammary artery under fluoroscopy. The anastomosis was completed over the catheter using sutures and the application of fibrin glue. Eight animals underwent the anastomosis after their sacrifice. The other 6 animals were put on closed chest cardiopulmonary bypass and had their anastomosis done after intraaortic balloon occlusion and cardioplegic arrest of the heart. All animals had an angiographic and pathologic examination at the completion of the anastomosis. RESULTS: Anastomosis was completed in all dogs. Three anastomoses leaked and two were noted to be stenosed at completion of the anastomosis. One leak was sealed by application of fibrin glue. Both stenotic anastomoses were caused by suturing of the back wall when a short angiographic catheter could not be positioned across the anastomosis. CONCLUSIONS: Minimally invasive totally thoracoscopic mammary-to-coronary artery bypass grafting with catheter assistance is feasible. Technical improvement and appropriate instrumentation are required to minimize anastomotic failure.

Assessment of arterial stenosis in a flow model with power Doppler angiography: accuracy and observations on blood echogenicity.

The objective of the project was to study the influence of various hemodynamic and rheologic factors on the accuracy of 3-D power Doppler angiography (PDA) for quantifying the percentage of area reduction of a stenotic artery along its longitudinal axis. The study was performed with a 3-D power Doppler ultrasound (US) imaging system and an in vitro mock flow model containing a simulated artery with a stenosis of 80% area reduction. Measurements were performed under steady and pulsatile flow conditions by circulating, at different flow rates, four types of fluid (porcine whole blood, porcine whole blood with a US contrast agent, porcine blood cell suspension and porcine blood cell suspension with a US contrast agent). A total of 120 measurements were performed. Computational simulations of the fluid dynamics in the vicinity of the axisymmetrical stenosis were performed with finite-element modeling (FEM) to locate and identify the PDA signal loss due to the wall filter of the US instrument. The performance of three segmentation algorithms used to delineate the vessel lumen on the PDA images was assessed and compared. It is shown that the type of fluid flowing in the phantom affects the echoicity of PDA images and the accuracy of the segmentation algorithms. The type of flow (steady or pulsatile) and the flow rate can also influence the PDA image accuracy, whereas the use of US contrast agent has no significant effect. For the conditions that would correspond to a US scan of a common femoral artery (whole blood flowing at a mean pulsatile flow rate of 450 mL min(-1)), the errors in the percentages of area reduction were 4.3 +/- 1.2% before the stenosis, -2.0 +/- 1.0% in the stenosis, 11.5 +/- 3.1% in the recirculation zone, and 2.8 +/- 1.7% after the stenosis, respectively. Based on the simulated blood flow patterns obtained with FEM, the lower accuracy in the recirculation zone can be attributed to the effect of the wall filter that removes low flow velocities. In conclusion, the small errors reported in vitro may support the clinical use of this technique.

[Urinoma in newborn infants complicating congenital uropathy. 4 cases]. / Urinome du nouveau-né compliquant une uropathie congénitale. Quatre observations.

The authors report about four cases of urinoma detected during the neonatal period in three boys and one girl with congenital uropathy. It appeared as an infravesical obstruction in three cases (2 posterior urethral valves, one anterior urethral diverticulum) and as an obstruction of the pyeloureteral junction in the last case. The examination was prompted by the detection of a mass in the side during the clinical examination. The diagnosis is based on ultrasound, which evidences the liquid and extrarenal character of the urinoma and often allows demonstrating the underlying uropathy. The kidney may be difficult to localize if the urinoma is very large. IVP or radionuclide scanning may contribute to the diagnosis as they allow assessing the functional value of the kidney. The urinoma protects the kidney from the consequences of uropathy by allowing a relative decompression of the pyelocaliceal structures.

[X-ray computed tomographic aspects of mesenteric panniculitis]. / Aspect tomodensitométrique de la panniculite mésentérique.

Mesenteric panniculitis also known as lipodystrophy is an inflammatory condition of adipose tissue. A case of a 55 year old, female who presented a weight loss and a tender palpable mass located in the left flank is reported. CT patterns were not specific but might suggest the diagnosis: fatty mass, with a higher density than subcutaneous fat, located in the root of the mesentery and surrounding mesenteric vessels without distoting them. Intestinal loops were only pulled in periphery. This signs are not always present and even in this typical pattern mesenteric panniculitis could not be differentiated from liposarcoma. Thus an histological proof was needed. The evolution was good, with resolution of the abdominal pain. The knowledge of this rare Radioclinical syndrome should prevent any aggressive therapy.

A new canine carotid artery bifurcation aneurysm model for the evaluation of neurovascular devices.

BACKGROUND AND PURPOSE: Stents are increasingly used for coiling of difficult aneurysms, to reduce the risk of recurrences, or to modify blood flow. Currently available bifurcation aneurysm models are ill-suited to assess stent performance before clinical use. We designed a new wide-neck canine T-type bifurcation aneurysm model. Its potential value as a training tool as well as in the evaluation of new techniques or embolic agents was assessed. Our first task was to verify that recurrences occurred after satisfactory coiling. A second aim of this preliminary work was to assess if the new model could recreate the technical challenges involved in bifurcation aneurysms. MATERIALS AND METHODS: We introduce a new canine wide-neck bifurcation aneurysm model, created by using a vein pouch at the apex of an end-to-side anastomosis of the carotid arteries, with flow reversal in the proximal RCA by ligation of the innominate artery. Three aneurysms were treated with coil embolization, 10 were treated with stents (7 self-expandable, 3 balloon-expandable), and 3 were left untreated. Aneurysms were followed by duplex ultrasonography and angiography, and studied with macroscopic photography after euthanasia 11.8 +/- 3.9 months after surgery. RESULTS: All aneurysms remained patent at 9.0 +/- 3.6 months' follow-up. Coiling led to recurrences by 3 months in all 3 cases. Stent placement was technically difficult in all cases and did not lead to aneurysm thrombosis or neointimal closure of the aneurysm neck at 3 months. CONCLUSIONS: This model may be suitable for studying the effects of endovascular treatment on aneurysm and branch occlusion rates, for preclinical testing of stents and other intravascular devices, and for training students of endovascular technique.

Potential Applications of Untethered Microdevices in the Blood Vessels within the Constraints of an MRI System.

This paper presents potential medical applications that an untethered microdevice in the cardiovascular system could perform within an MRI system. Recent developments and continuing evolution in micro/nano fabrication and design techniques will enable the development of functional microdevices able to explore the cardiovascular system. The Magnetic Resonance Submarine (MR-Sub) project is a first step towards this goal. Magnetic force generated by the gradient coils of an MRI system provides a propulsion mechanism that simplifies miniaturization and bypasses energetic challenges. Untethered microdevices may play an important complementary role in the next generation of minimally invasive tools. A better efficiency and targetability of the treatments will be achieved when microsystems such as the MR-Sub will allow a more extensive access to smaller blood vessels.

Transvenous coil embolization of an extrahepatic portosystemic shunt in a dog: a naturally occurring model of portosystemic malformations in humans.

Congenital patent ductus venosus (PDV) occurs far more commonly in dogs than in people; consequently, the natural course of the disease in dogs was studied as a model to understand the pathophysiology behind the vascular anomaly and its response to therapy better. In this report, the authors describe the results of percutaneous coil embolization as a single procedure in a dog with a single congenital extrahepatic portocaval shunt and compare portosystemic vascular anomalies (PSVA) seen in dogs with those seen in children.

Posttraumatic arteriovenous fistula and subclavian vein thrombosis: treatment by percutaneous arterial embolization and vein angioplasty.

A 71-year-old woman had edema and venous dilatation of her upper right limb that caused painful functional disability following a shoulder injury. Arteriograms demonstrated an arteriovenous fistula between the subclavian artery and vein associated with thrombosis of the vein at the same level. The arteriovenous fistula was found to have multiple arteriovenous communications. Because of associated distal venous thrombosis, venous drainage was retrograde through the brachial vein. The inflow arteries of the fistula were embolized and then the subclavian vein thrombosis was recanalized, dilated, and an endoluminal stent inserted. Clinical signs completely resolved.

Infection with fatal outcome after endovascular metallic stent placement.

The authors describe a case in which infection developed in a patient after placement of a metallic endoprosthesis in the iliac artery. The patient died of respiratory failure secondary to sepsis. Imaging studies did not reveal an abscess, aneurysm, or stent occlusion. Stent cultures and hemocultures grew Staphylococcus aureus. As with any foreign body, infectious complications may occur after insertion of metallic stents and should be recognized as soon as possible to initiate appropriate therapy.

Imaging of renovascular hypertension: respective values of renal scintigraphy, renal Doppler US, and MR angiography.

Renovascular hypertension affects 15%-30% of patients who have clinical criteria suggestive of renovascular disease. Noninvasive screening is crucial for patient selection prior to conventional angiography and renal revascularization. Renal scintigraphy has been reported to be sensitive for detection of renovascular hypertension, but some of its limitations (eg, in the setting of bilateral renal artery stenosis and renal failure) should be considered. Doppler ultrasonography (US) allows direct evaluation of the renal arteries as well as transrenal Doppler waveform analysis, but it remains operator dependent. Gadolinium-enhanced magnetic resonance (MR) angiography is becoming an excellent alternative to conventional angiography. The main limiting factors of this technique are inadequate visualization of segmental and accessory renal arteries as well as a tendency toward overestimation of stenoses. Given the high cost and low availability of MR angiography, scintigraphy and Doppler US should be considered the primary studies in screening for renovascular hypertension. MR angiography could be reserved for patients with inconclusive scintigraphic and Doppler US results, patients with high clinical suspicion of renovascular hypertension, and patients with a contraindication to conventional angiography.