Reduced Activity of von Willebrand Factor after Flow-Diverting Stent Implantation for Intracranial Aneurysms: A Link to Acquired von Willebrand Disease?

BACKGROUND AND PURPOSE: Vascular devices generating high shear stress can cause type 2A acquired von Willebrand disease, which is characterized by low von Willebrand factor activity accompanied by hemorrhagic complications. The braided mesh structure of flow-diverting stents with a relatively small strut size can create abnormally high shear stress while arterial blood flows through the stent struts into the aneurysm, and flow-diverting stent may be associated with reduced von Willebrand factor activity. MATERIALS AND METHODS: Aneurysmal morphologic parameters and patient data were examined retrospectively among patients who had an unruptured intracranial aneurysm treated with a flow-diverting stent. The RISTOtest (test for whole blood ristocetin-induced platelet aggregation) for von Willebrand factor activity, as well as tests for aspirin and clopidogrel/prasugrel effectiveness, were performed immediately before the endovascular procedure and 24 hours later by multiple electrode aggregometry. RESULTS: A total of 39 patients with 56 aneurysms were recruited, and statistical analyses were performed in 32 patents with 49 aneurysms. Compared with the baseline values, von Willebrand factor activity was reduced in 16 patients but increased in 23 patients. Aneurysmal variables (eg, neck area, volume, volume-to-neck area ratio, size ratio, and morphologic index) clearly distinguished patients with reduced von Willebrand factor activity from those with nonreduced von Willebrand factor activity. The receiver operating characteristic curve showed that the morphologic index and volume had the highest discriminative power, with an area under the curve of 0.99. CONCLUSIONS: In high-volume/large-neck aneurysms, flow-diverting stent implantation can cause reduced von Willebrand factor activity, which may be linked causally to acquired von Willebrand disease.

Intracranial Serpentine Aneurysms: Spontaneous Changes of Angiographic Filling Pattern.

BACKGROUND AND PURPOSE: Serpentine aneurysms are partially thrombosed aneurysms with an eccentrically located tortuous intra-aneurysmal vascular channel. The large size, distinctive neck anatomy, and supply of the brain parenchyma by the outflow tract pose technical challenges in treatment. The aim of this study was to discuss the endovascular treatment results and illustrate the dynamic nature of serpentine aneurysms. Spontaneous transformation of saccular and fusiform aneurysms into serpentine morphology, along with a case of serpentine-into-fusiform aneurysm transformation during follow-up, is presented. MATERIALS AND METHODS: A retrospective analysis from 3 institutions revealed 15 patients with serpentine aneurysms who underwent diagnostic evaluation and endovascular treatment. Nine of the 15 patients underwent endovascular occlusion of the parent vessel with detachable balloon or coils. Six of the 15 patients underwent aneurysm and parent artery occlusion with coiling. RESULTS: In 11 patients, improvement or resolution of symptoms was achieved by an endovascular approach without any treatment-related morbidity. Morbidity related to treatment in the immediate postoperative period was seen in 3 patients, with resolution of the deficits at long-term follow-up in 2 patients and persistence of a mild deficit in 1 patient. Endovascular treatment failed to achieve resolution of symptoms in a case with a basilar tip aneurysm treated by aneurysm coiling. CONCLUSIONS: Serpentine aneurysms are dynamic structures with spontaneous transformation possible from a saccular or fusiform shape into a serpentine configuration. An endovascular approach by parent vessel occlusion or intra-aneurysmal occlusion is a successful treatment technique for serpentine aneurysms.

Endovascular management of congenital arteriovenous fistulae in the neck.

PURPOSE: The purpose of this study was to evaluate congenital arteriovenous fistulae in the neck, including vertebrovertebral and carotico-jugular arteriovenous fistula, with their endovascular management. MATERIALS AND METHODS: Six patients with congenital arteriovenous fistulae in the neck who underwent endovascular treatment between March 2001 and December 2013 at the Department of Radiology, Ege University School of Medicine were enrolled into this retrospective study. There were four men and two women, with a mean age of 8.6 (range 4-17)years. Patients' demographics and symptoms were noted. Diagnostic computed tomography and/or magnetic resonance angiography were available in all patients. Parent artery and vein of the arteriovenous fistula, location of the fistula, the other features of fistula, endovascular occlusion site, number and type of endovascular materials, and length of follow-up were reviewed. RESULTS: Four patients had vertebrovertebral fistula, while two patients had carotido-jugular fistula (fistula between maxillary artery and external jugular vein). Four patients underwent detachable balloon occlusion together with coil embolization, while two patients underwent detachable balloon occlusion only. The parent artery was occluded in five patients without clinical consequences, and the remaining fistula was occluded with preservation of the parent artery. The patients did not have any complication in the follow-up period (mean follow-up, 9months). CONCLUSION: Congenital arteriovenous fistulae in the neck are extremely rare. Endovascular fistula occlusion with parent vessel sacrifice appears to be a safe and minimally invasive treatment option with good results during the follow-up period.

The short- and long-term effectiveness of transcatheter arterial embolization in patients with intractable hematuria.

PURPOSE: Selective transarterial embolization (TAE) of the internal iliac artery is a well-known alternative technique to control intractable bladder hemorrhage (IBH). We explored the short- and long-term effectiveness of, and clinical outcomes after, TAE in patients with IBH. MATERIALS AND METHODS: In this retrospective study, we reviewed the hospital records of 18 IBH patients non-responsive to conservative medications who underwent TAE between January 2003 and May 2014. The early- and long-term effectiveness of TAE was investigated in the context of hematuria control, complications, mortality, requirement for blood transfusions, and hematocrit level. RESULTS: Sixteen of the 18 patients underwent endovascular treatment; the technical success rate was 88%. TAE allowed complete remission in 16 patients (100% clinical success). On follow-up, mean hematocrit (P=0.003) and hemoglobin (P=0.005) levels significantly improved. Thirteen of the 16 patients (81%) required no further emergency admission after TAE during a mean follow-up period of 18.1months (range, 3-105months). CONCLUSION: TAE is a feasible, effective, and safe technique in both the short- and long-term for the treatment of IBH.

The rapid pull-back technique for navigation across a wide-necked aneurysm. a report of four cases.

Embolization of wide-necked and/or giant aneurysms may fail due to the inability to pass across the aneurysm neck. We describe the rapid bull-back technique used in four patients in which a small diameter microcatheter with the aid of a hydrophilic microguidewire was navigated along the inner surface of the aneurysm, making a loop in the dome, exiting the neck to reach distal intracranial vessels. After withdrawal of microguidewire, the microcatheter is pulled back rapidly up to a predetermined length. This maneuver results in elimination of the loop, straightening the microcatheter to allow an exchange procedure for another device to cross the neck distally and continue the embolization procedure. The rapid pull-back technique is useful during the endovascular treatment of wide-necked and/or giant aneurysms as it helps to achieve reliable access to the distal parent vessel with the microcatheter. This is of increasing importance since an increasing number of aneurysms will be treated in the future with refinements in various intracranial stents.

Endovascular Management of Vascular Injury during Transsphenoidal Surgery.

Vascular injury is an unusual and serious complication of transsphenoidal surgery. We aimed to define the role of angiography and endovascular treatment in patients with vascular injuries occurring during transsphenoidal surgery. During the last ten-year period, we retrospectively evaluated nine patients with vascular injury after transsphenoidal surgery. Eight patients were symptomatic due to vascular injury, while one had only suspicion of vascular injury during surgery. Four patients presented with epistaxis, two with subarachnoid hemorrhage, one with exophthalmos, and one with hemiparesia. Emergency angiography revealed a pseudoaneurysm in four patients, contrast extravasation in two, vessel dissection in one, vessel wall irregularity in one, and arteriovenous fistula in one. All patients but one were treated successfully with parent artery occlusion, with one covered stent implantation, one stent-assisted coiling method, while one patient was managed conservatively. One patient died due to complications related to the primary insult without rebleeding. Vascular injuries suspected intra or postoperatively must be investigated rapidly after transsphenoidal surgery. Endovascular treatment with parent artery occlusion is feasible with acceptable morbidity and mortality rates in the treatment of vascular injuries occurring in transsphenoidal surgery.

Taurine suppresses oxidative stress-potentiated expression of lectin-like oxidized low-density lipoprotein receptor and restenosis in balloon-injured rabbit iliac artery.

1. In endothelial cells, the major receptor for the binding and internalization of oxidized low-density lipoprotein (LDL) is the lectin-like oxidized LDL receptor (LOX-1). The aim of the present study was to investigate the effects of taurine on intimal thickening and LOX-1 expression under normal and oxidative conditions. 2. The iliac artery of rabbits were subjected to balloon injury and oxidative stress was induced by 14 days treatment of rabbits with 75 mg/kg, s.c., buthionine sulfoximine (BSO), a specific inhibitor of glutathione synthesis. Taurine was administered in drinking water (1%, w/v) for 14 days in the presence (BSO + Taurine group) and in the absence of BSO treatment (Taurine group). In taurine and placebo groups, rabbits were injected with 4 mL, s.c., 0.9% NaCl (vehicle for BSO) for 14 days. 3. Taurine (1% in drinking water, w/v) preserved plasma levels of anti-oxidants and lowered the increased blood pressure induced by BSO. The stenosis rate of 29.92% in the placebo group increased to 72.20% in the BSO group, which was significantly reduced to 42.21% by taurine (P < 0.001; n = 5). Localization of LOX-1 to the intima and media of the iliac artery was demonstrated in the present study. Taurine treatment reduced the BSO-induced increase in LOX-1 expression at both the protein and mRNA levels (P < 0.05 and P < 0.01, respectively). 4. The results demonstrate that the stenosis rate and LOX-1 expression correlate well with oxidative status. Manipulation of LOX-1 expression by taurine may have therapeutic benefits in preventing restenosis.

Stent implantation in chronic mesenteric ischemia.

BACKGROUND: Chronic mesenteric ischemia (CMI) is a life-threatening disorder, which is usually associated with stenosis or occlusion of celiac or mesenteric arteries. PURPOSE: To review our experience and to assess short-term results of stent placement in stenotic mesenteric arteries. MATERIAL AND METHODS: Primary stent placement was performed in 15 patients who had nausea, vomiting, postprandial pain, and weight loss due to steno-occlusive diseases of mesenteric arteries. After stenting, the patients were followed clinically and with Doppler ultrasound at 1, 6, and 12 months. Symptomatic patients with restenosis were examined with digital subtraction angiography and were referred for retreatment with balloon dilatation. RESULTS: Twenty-three stenoses and 11 occlusions were detected in 15 patients, and 18 stenoses were treated with primary stenting. Single-vessel endovascular treatment was performed in 12 patients. In three patients, two arteries were stented in the same session. Technical success rate was 18/18 (100%). Clinical success was achieved in 13/15 (86.6%) patients. First-month mortality was 13%. During the mean 16.1-month follow-up period, restenoses developed in three patients. One of them was successfully treated with balloon angioplasty. Primary patency was 9/11 (81%) and primary assisted patency was 81% at 12 months. The complication rate was 1/15 patients (0.06%). CONCLUSION: Our experience suggests that stent placement has a potential role in chronic mesenteric ischemia with low incidence of complications and high technical and clinical success rates.

Telomeric restriction analysis of vascular smooth muscle cells following balloon angioplasty in rabbits.

Intimal hyperplasia due to smooth muscle cell proliferation and migration has been reported to be responsible for the pathogenesis of atherosclerosis and restenosis, manifested following balloon angioplasty. In this study, we employed the balloon angioplasty model to study telomere length regulation in proliferating vascular smooth muscle cells. Our results showed that balloon angioplasty in iliac arteries resulted in intimal hyperplasia due to proliferation of the smooth muscle cells and small size telomeric restrictional fragments were evident in injured arteries.

Continuous intra-arterial infusion of nimodipine during embolization of cerebral aneurysms associated with vasospasm.

BACKGROUND AND PURPOSE: Despite rigorous efforts, cerebral vasospasm remains an important cause of morbidity and mortality in patients who survive their initial subarachnoid hemorrhage. In cases of intracranial ruptured aneurysm associated with vasospasm, we evaluated the effectiveness of combined embolization of an aneurysm and intra-arterial infusion of nimodipine, which continued during the entire procedure. MATERIALS AND METHODS: Ten patients with ruptured aneurysms associated with vasospasm who were treated in a single session were reviewed retrospectively. After initial intra-arterial infusion of nimodipine (1-2 mg within 10-15 minutes), they underwent occlusion of the aneurysm with coils under continuous intra-arterial infusion of nimodipine at a dose of 1 mg per hour. RESULTS: Angiography showed severe proximal vasospasm in 1 patient, proximal and distal in 3 patients, and distal in 3 patients. There was also moderate proximal vasospasm in 4 patients, proximal and distal in 1 patient, and distal in 1 patient. Complete occlusion of the aneurysm was achieved in 5 patients, incomplete occlusion in 3 patients, and a small neck remnant in 2 patients. Final angiograms also demonstrated complete clearance of a proximal spasm in 4 patients, and complete clearance of proximal and distal spasms in another 4 patients. Mean initial dose of nimodipine was 1.375 mg, and mean continuous infusion dose was 1.275 mg (mean total dose, 2.65 mg). No medical complications related to extended infusion of nimodipine occurred. CONCLUSION: In this small series, extended intra-arterial infusion of nimodipine up to the end of the embolization procedure was effective and safe in patients with a ruptured aneurysm and associated vasospasm. This technique seems to increase the security of the procedure as well as force further vasorelaxation when the endovascular route is used to treat both the aneurysm and vasospasm in a single step.

Ruptured petrous carotid pseudoaneurysm due to tuberculous otitis: endovascular treatment.

SUMMARY: We report the imaging findings and endovascular treatment in an unusual case of petrous internal carotid artery pseudoaneurysm due to primary tuberculous otitis. The aneurysm was recognized and ruptured during a surgical intervention for otitis. Successful endovascular treatment of the aneurysm was performed by occlusion of the parent vessel using detachable balloon and coils.

Sinistral portal hypertension; imaging findings and endovascular therapy.

Sinistral portal hypertension, a rare and localized form of portal hypertension, is the result of splenic vein thrombosis or obstruction and may cause gastrointestinal hemorrhages from the esophageal and gastric varices. This report presents two cases (69- and 10-year-old females) of bleeding gastric varices. The patients were diagnosed as having sinistral portal hypertension. Splenic artery embolization was performed in both patients to overcome intractable bleeding, and the clinical outcome was good.

Embolisation of both fistulae through the same carotid artery tear in a patient with bilateral traumatic caroticocavernous fistulae.

Endovascular treatment of traumatic caroticocavernous fistulae (CCF) may present technical difficulties with specific angiographic dilemmas. We report endovascular techniques used in a patient with bilateral post-traumatic CCF, high-flow on one side, and slow-flow on the other. Complete closure of both was achieved through the same carotid artery tear. To our knowledge, transarterial venous coil embolisation of a low-flow fistula through a contralateral carotid artery tear, with transarterial detachable balloon embolisation of the ipsilateral high-flow fistula has not been described previously.

Posttraumatic intradural internal carotid artery-cavernous sinus fistula associated with ipsilateral carotid dissection. Transarterial embolization with detachable coils.

SUMMARY: We describe a relatively unusual case of traumatic direct carotid-cavernous fistula in association with a giant intradural venous pouch and ipsilateral carotid dissection, related to carotid artery fistula located in the supraclinoid segment just below the origin of posterior communicating artery. Endovascular therapy could be accomplished by use of detachable coils transarterially. Awareness of an unusual intradural origin of a carotid-cavernous sinus fistula and the possibility of an embolization should be kept in mind.

Embolization of visceral pseudoaneurysms with platinum coils and N-butyl cyanoacrylate.

BACKGROUND: We evaluated the efficacy of transcatheter embolization in visceral artery pseudoaneurysms with platinum coils and N-butyl-cyano-acrylate (NBCA). METHODS: Over the past 7 years, 20 patients were treated by transcatheter embolization in the same sitting with diagnostic angiography. Four right hepatic, one cystic, two gastroduodenal, one cavernosal artery, three superior mesenteric artery branch, and 11 renal artery branch pseudoaneurysms were included in the study. RESULTS: Surgery was completely avoided in 19 patients. In the remaining patient with a superior mesenteric artery branch pseudoaneurysm, endovascular embolization was unsuccessful. Eighteen pseudoaneurysms were thrombosed with coil embolization alone. The remaining three pseudoaneurysms needed NBCA embolization. Two patients died from sepsis within 5 weeks after embolization. CONCLUSION: Emergent diagnosis and treatment are essential in visceral artery pseudoaneurysms because of the high rate of death. Transcatheter embolization with platinum coils is an efficient, safe treatment of choice. NBCA may be used to avoid proximal embolization of the visceral arteries that could not be catheterized selectively because of tortuosity, vessel size, or anatomic location.

Mesenteric artery aneurysms in intestinal tuberculosis as a cause of lower gastrointestinal bleeding.

A 41-year-old woman with intestinal tuberculosis developed massive lower gastrointestinal hemorrhage. Angiographic examinations showed two aneurysms arising from the proximal branches of the superior mesenteric artery, one of which was resected and the other one was successfully embolized with microcoils. Understanding the angiographic features of the disease with gastrointestinal hemorrhage helps in making an appropriate clinical decision for the treatment strategy.

Aortic origin of right hepatic artery and superior mesenteric origin of splenic artery: two rare variations demonstrated angiographically.

Anatomical variations of the celiac trunk and superior mesenteric artery are not infrequent. Knowledge of the existing aberrations is important in planning and conducting surgical or radiological procedures. A case of right hepatic artery arising independently from the aorta supplying an hepatocellular carcinoma was identified, through which transarterial chemoembolization was successfully performed. A second case is presented with a common splenomesenteric trunk branching into the splenic and superior mesenteric arteries. These two cases represent exceptional arterial variations in the upper abdomen.

Intradural Aneurysm Caused by Arterial Injury during Surgery: Treatment with Coil Embolization.

SUMMARY: We described a patient with subarachnoid hemorrhage due to a ruptured intradural aneurysm caused by arterial injury during surgery and severe symptomatic vasospasm. The iatrogenic posttraumatic aneurysm was occluded by using GDC with preservation of parent artery followed by intraarterial infusion of papaverine to treat vasospasm as an one-stage procedure. This resulted in significant angiographic resolution of the vasospasm and the patient's clinical outcome was excellent. Endovascular approach to posttraumatic intracranial aneurysms and endosaccular GDC embolization of aneurysm with concomitant intraarterial papaverine infusion to treat vasospasm are discussed.