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Biomedical subjects

Ajay K Wakhloo

Publications and source records attributed to Ajay K Wakhloo.

17 recordsLinked to original sources
PubMed2006

Infantile midline facial hemangioma with agenesis of the corpus callosum and sinus pericranii: another face of the PHACE syndrome.

BACKGROUND: In the majority of cases, infantile hemangiomas are not associated with any other abnormalities. Occasionally, they may indicate the presence of systemic malformations. PHACE syndrome includes the coexistence of hemangioma, posterior fossa brain abnormalities, arterial anomalies, coarctation of the aorta, cardiac defects, and eye abnormalities. We report a case of a 2-month-old female with PHACE syndrome who also had sinus pericranii. CLINICAL CASE: A 2-month-old girl was seen for a plaque-like, segmental, midfacial hemangioma, with recurrent hemorrhages, noted at birth. As part of the PHACE syndrome, she had a midline facial hemangioma, absent corpus callosum, hypoplastic internal carotid artery, and an abnormal tortuous dysplastic basilar artery. Digital subtraction angiography showed sinus pericranii. The patient underwent successful endovascular embolization of the hemangioma that prevented further bleeding. CONCLUSION: Sinus pericranii is a rare finding that has not, to our knowledge, been previously associated with PHACE syndrome. Central nervous system, not only posterior fossa, abnormalities are frequently encountered in PHACE syndrome. Endovascular embolization of the facial hemangioma in our patient was a useful therapy.

Abnormalities, Multiple↗
PubMed2005

Polyglycolide/polylactide-coated platinum coils for patients with ruptured and unruptured cerebral aneurysms: a single-center experience.

BACKGROUND AND PURPOSE: Recanalization of cerebral aneurysm is a limitation of bare platinum coils (BPCs). In a swine aneurysm model, polyglycolide/polylactide (a polymer)-coated platinum coils (Matrix) accelerated clot fibrosis and reduced recanalization rate and aneurysmal volume. We aimed to evaluate the safety of Matrix coils in patients with intracranial aneurysm. METHODS: This is a single-center, prospective study of patients with intracranial aneurysms treated with Matrix alone or in combination with BPCs. Follow-up evaluation included a 1-month clinical evaluation and a 6- and 12-month clinical and angiographic examination. Primary adverse events included death, stroke, and permanent neurological deficits. RESULTS: Between May 2002 and January 2004, 52 patients (range 34 to 79 years of age; 38 females) were treated for 54 aneurysms (size 7.9+/-4.6 mm; neck 3.9+/-1.5 mm; 26 ruptured). Matrix alone was used in 13 aneurysms. In 39, we used a combination of Matrix and BPCs. Twenty-one aneurysms had a 6-month follow-up examination (11 Matrix; 10 Matrix combined with bare platinum), and 11 completed the 12-month follow-up evaluation (Matrix only). Adverse events not related to the procedure were 2 deaths (ruptured basilar aneurysms) and 1 stroke at day 10 postcoiling secondary to vasospasm. Procedure-related adverse events were 2 strokes. At 6-month follow-up (n=21) evaluation, 2 of 3 recanalizations needed retreatment. At 12-month follow-up (n=11), there was no recanalization in patients treated with Matrix alone and no significant reduction in aneurysmal size. CONCLUSIONS: Polyglycolide/polylactide-coated coils had a satisfactory safety profile. Significant aneurysmal size reduction after coiling was not observed.

Adult↗
PubMed2005

Morphological age-dependent development of the human carotid bifurcation.

The unique morphology of the adult human carotid bifurcation and its sinus has been investigated extensively, but its long-term, age-dependent development has not. It is important fundamentally and clinically to understand the hemodynamics and developmental forces that play a role in remodeling of the carotid bifurcation and maturation of the sinus in association with brain maturation. This understanding can lead to better prognostication and therapy of carotid disease. We analyzed the change of sinus morphology and the angle of the carotid bifurcation in four postnatal developmental stages (Group I: 0-2 years, Group II: 3-9 years, Group III: 10-19 years, and Group IV: 20-36 years, respectively) using multiprojection digital subtraction angiograms and image post-processing techniques. The most significant findings are the substantial growth of the internal carotid artery (ICA) with age and the development of a carotid sinus at the root of the ICA during late adolescence. The bifurcation angle remains virtually unchanged from infancy to adulthood. However, the angle split between the ICA and external carotid artery (ECA) relative to the common carotid artery (CCA) undergoes significant changes. Initially, the ICA appears to emanate as a side branch. Later in life, to reduce hydraulic resistance in response to increased flow demand by the brain, the bifurcation is remodeled to a construct in which both daughter vessels are a skewed continuation of the parent artery. This study provides a new analysis method to examine the development of the human carotid bifurcation over the developmental years, despite the small and sparse database. A larger database will enable in the future a more extensive analysis such as gender or racial differences.

Adolescent↗
PubMed2005

Functional angiography.

The discovery of X-rays over a century ago enabled noninvasive examination of the human body. Contrast agents that enhanced X-ray images were soon developed that advanced angiology by allowing exploration of the vascular tree. Starting as a diagnostic tool, angiography underwent technological transformations over the last century and became a basis for interventional therapy as well. Initially a static two-dimensional record of the vasculature on screen films, angiography has evolved to real-time two-dimensional display of the vasculature on television monitors, three-dimensional reconstruction from computerized tomographic (CT) scans, and, more recently, three-dimensional cone-beam reconstruction. Cinematographic angiography is referred to as dynamic angiography in current terminology, but it essentially provides no more than images of vascular structures and changes therein. Although dynamic angiography has facilitated advances in image-guided interventions, the evaluation of blood flow rate, or perfusion, and blood flow velocity using angiography remains elusive. Many lines of research have been pursued toward enabling such evaluations, but none have found their way into clinical practice. This article reviews angiographic flow assessment methods attempted over the past several decades and explores some new avenues that may facilitate the transfer of such methods into the clinical practice of diagnostic and interventional angiography and, eventually, contribute to better patient care.

Angiography↗
PubMed2005

Transvenous n-butyl-cyanoacrylate infusion for complex dural carotid cavernous fistulas: technical considerations and clinical outcome.

BACKGROUND AND PURPOSE: Endovascular transvenous embolization has been advocated as the treatment technique for dural carotid cavernous fistulas (dCCFs). Most centers use platinum coils primarily. The purpose of this study was to evaluate the technical aspects, efficacy, and safety of transvenous n-butyl cyanoacrylate (n-BCA) infusion in dCCFs as a primary alternative or adjunct to coil embolization. METHODS: We retrospectively evaluated 14 patients with dCCFs who were treated at this institution from 1999 to 2004 by using n-BCA infusion alone or in combination with coils. The efficacy of treatment and safety aspects were studied in dCCFs of Barrow type B (4/14), C (2/14), and D (8/14). Six patients were treated with transvenous n-BCA infusion alone in the cavernous sinus, 7 with a combination of transvenous n-BCA and coil embolization, and one with transvenous n-BCA combined with transarterial polyvinyl alcohol (PVA)-particle embolization of the feeding arteries. RESULTS: An angiographic obliteration and clinical cure was achieved in all patients. Technical complications were nonsymptomatic and included spillage of an n-BCA droplet into a middle cerebral artery branch retrograde through the arteriovenous fistulas in one patient and perforation of the inferior petrosal sinus during microcatheter placement in another. A third patient developed temporary palsy of the sixth cranial nerve a few days after the treatment. CONCLUSION: In this small series, the use of n-BCA either alone or in conjunction with detachable coils was a safe and effective technique for the treatment of symptomatic patients presenting with complex dCCFs.

Adult↗
PubMed2005

Morphology of elastase-induced cerebral aneurysm model in rabbit and rapid prototyping of elastomeric transparent replicas.

In this work, we describe a methodology to fabricate transparent elastomeric vascular replicas using rapid prototyping techniques. First, the three-dimensional morphology of an elastase-induced aneurysm model in rabbit is acquired. The morphology is reconstructed from in vivo rotational angiography and it is compared with three-dimensional reconstructions obtained by computerized tomography and magnetic resonance imaging of an intraluminal arterial cast that was obtained from the same animal at sacrifice. Results show that resolution of the imaging modality strongly influences the level of detail, such as small side branches, in the final reconstruction. We developed an average morphology model for elastase-induced aneurysms in rabbits including the surrounding vasculature and describe a method for rapid prototyping of vascular models from the three-dimensional morphology. Our replicas can be manufactured in a short period of time and the final product is optically clear. In addition, the elasticity of the models can be controlled to represent arterial elasticity, which makes them ideal for optical investigations of detailed flow dynamics using measurement tools such as particle image velocimetry.

Animals↗
PubMed2004

Hemodynamics of carotid artery atherosclerotic occlusive disease.

Hemodynamic mechanisms for the initiation and progression of carotid bifurcation atherosclerotic occlusive disease have been extensively researched during the past few decades. Attention has focused on the carotid bulb, or sinus, where most atherosclerotic plaques are found. Herein, the authors review the seminal works that have led to an understanding of not only complex local hemodynamics but also the elicited specific biologic response. In addition, new analysis of the age-dependent morphologic maturation of the human carotid bifurcation is unveiled. Understanding the role of hemodynamics in atherogenesis may lead to the improvement of minimally invasive endovascular therapy and noninvasive strategies.

Brain↗
PubMed2004

MR findings of cortical blindness following cerebral angiography: is this entity related to posterior reversible leukoencephalopathy?

We describe MR findings in three patients who experienced transient cortical blindness following cerebral angiograms. All angiograms were performed by using the same nonionic contrast medium. On the basis of similar clinical and radiologic findings, we believe that this entity is closely related to and probably has the same pathophysiology as posterior reversible leukoencephalopathy.

Aged↗
PubMed2003

Combined transvenous and transarterial embolization of a tentorial-incisural dural arteriovenous malformation followed by primary stent placement in the associated stenotic straight sinus. Case report.

Dural arteriovenous malformations (AVMs) involving the tentoria-incisura are associated with an aggressive clinical course characterized by subarachnoid and intracranial hemorrhage (ICH). In these lesions, venous outflow obstruction precipitates leptomeningeal venous drainage, resulting in the arterialization of pial veins and the formation of venous aneurysms, both of which are prone to hemorrhage. Stenotic lesions of the dural sinuses also contribute to the development of retrograde leptomeningeal drainage, which is responsible for the aggressive clinical course of the dural AVM. Endovascular approaches are successful in the treatment of these lesions and of any potential venous outflow obstruction caused by stenosis of a dural sinus. The authors report on a patient with a tentorial-incisural dural AVM and an accompanying stenotic venous sinus. A combined transvenous and transarterial embolization procedure was performed, resulting in complete obliteration of the dural AVM, followed by primary stent placement across a stenotic segment of the straight sinus and normalization of venous outflow. The authors conclude that dural AVMs can be treated safely by using a combined transarterial and transvenous approach and that an extensive search for venous outflow obstruction often reveals stenosis of a draining sinus. Consideration should be given to primary stent placement in the stenotic sinus to protect against ICH.

Arteriovenous Fistula↗
PubMed2002

Particle image velocimetry assessment of stent design influence on intra-aneurysmal flow.

Endovascular stenting appears to be an appealing treatment modality to selected complex intracranial aneurysms. However, stents currently used for endovascular treatment are not specifically designed for the cerebrovasculature. Stent parameters, such as porosity and filament size, have to be carefully optimized for long-term successful treatment. We investigated the influence of the stent filament size on the intraaneurysmal flow dynamics in a sidewall aneurysm model in vitro. Three helical stents with 76% porosity but different filament sizes of 178, 153, and 127 microm were studied using particle image velocimetry. Twenty-four pulsatile flow conditions were investigated. The results show that stenting significantly reduces intra-aneurysmal vorticity and the mean circulation inside the aneurysm is reduced to less than 3% of its value before stenting. For constant porosity, a further reduction of the mean circulation, up to 30% can be obtained by reducing the filament diameter. For a constant Womersley number, this further reduction is accentuated with increase in the peak Reynolds number. Further reduction in the mean circulation inside the aneurysm was not achieved for the 127 microm stent. With further reduction in filament diameter, the helical stent filaments positioned against the aneurysm neck started wavering with the flow transferring added momentum into the aneurysm. For stents of smaller filament diameter, a supporting ultrastructure is required.

Alloys↗
PubMed2002

Stent placement for the treatment of occlusive atherosclerotic carotid artery disease in patients with concomitant coronary artery disease.

OBJECT: The authors report their experience with carotid artery stent placement (CASP) in patients with concomitant carotid artery (CA) and coronary artery (CorA) diseases. METHODS: In a review of 320 consecutive patients who underwent CASP, the authors identified 49 with severe CorA disease in addition to significant CA stenosis, who had undergone CASP before planned CorA bypass grafting (CorABG). The average age of these 49 patients was 68 years. In 39 patients (80%) the New York Heart Association functional classification grade was IV and in 10 the grade was III. In 26 patients 50% or greater stenosis of the left main CorA was found. Seventeen patients (35%) suffered from either significant hemodynamic contralateral CA stenosis (> 60% stenosis; eight patients) or contralateral CA occlusion (nine patients). Sixteen patients (33%) had symptomatic CA disease. No cerebrovascular events occurred during CorABG. Four patients (8%) died of cardiac arrest and one patient (2%) suffered a major stroke within 30 days after the CorABG procedure. No patient experienced clinically significant recurrent CA stenosis during the study period (average clinical follow-up period 27 months). CONCLUSIONS: Carotid artery stent placement should be considered as an alternative for the management of concomitant CA and CorA diseases. These preliminary results support the feasibility and durability of CASP in the population studied.

Aged↗
PubMed2002

Stent-assisted coil placement in a wide-necked persistent trigeminal artery aneurysm with jailing of the trigeminal artery: a case report.

We report the successful stent placement and secondary coil placement in a wide-necked persistent trigeminal artery (TA) aneurysm, in which the internal carotid artery (ICA) was preserved and the TA "jailed." Nine-month follow-up angiography revealed a completely obliterated aneurysm and patent parent ICA and TA. MR images obtained at 16-mo follow-up showed no infarction of the brain in the distribution of the jailed TA. The risks of stent jailing and possible solutions are discussed.

Carotid Artery, Internal↗
PubMedDate not supplied

Effect of glacial acetic acid and ethiodized oil concentration on embolization with N-butyl 2-cyanoacrylate: an in vivo investigation.

BACKGROUND AND PURPOSE: Precise control of the polymerization dynamics of cyanoacrylate mixtures used in the embolization of cerebral arteriovenous malformations is required to achieve a safe and permanent obliteration of the lesion. In this study, in vivo embolization using mixtures of Histoacryl, Lipiodol Ultra-Fluid, and glacial acetic acid (GAA) was investigated. The present study investigated whether increased ethiodized oil concentration or the addition of GAA increased rate of embolization. METHODS: Using embolic mixtures containing Histoacryl (N-butyl 2-cyanoacrylate [NBCA]), the embolization process in the femoral and subclavian arteries of the rabbit was examined. Various embolic agents composed of ethiodized oil and N-BCA mixtures, either with or without the addition of minute quantities of GAA, were injected. Blood flow through the aforementioned arteries was measured during embolization. The transient decay of blood flow to zero was modeled, and an optimized model parameter, termed the time elapsed to flow arrest (TEFA) factor, was compared with the experimental data related to the embolization process. RESULTS: The TEFA factor was independent of the variation of the ethiodized oil concentration in the mixture (P >.05). In contradistinction, the addition of GAA significantly increased the TEFA factor (P <.05). Moreover, a linear relation between the TEFA factor and the quantity of GAA in the mixture was discerned. CONCLUSION: Predictable control of the embolization process with N-BCA in vivo is attained by varying the amount of GAA in the embolic mixture.

Acetic Acid↗
PubMedDate not supplied

Direct percutaneous puncture of a cervical internal carotid artery aneurysm for coil placement after previous incomplete stent-assisted endovascular treatment.

Direct percutaneous puncture for coil placement has been described for visceral aneurysms, but the procedure has not been previously reported for aneurysms of the head and neck. We report a case in which stent-assisted endovascular treatment was successfully combined with direct puncture for additional coil placement to treat a symptomatic giant aneurysm of the cervical internal carotid artery.

Aged↗