Karthikram Raghuram

Comparison of Devices Used for Stent-Assisted Coiling of Intracranial Aneurysms

Introduction Two self-expandable stents, the Neuroform and the Enterprise stent, are widely used for stent-assisted coiling (SAC) of complex shaped intracranial aneurysms. However, comparative knowledge about technical feasibility, peri- and post-procedural morbidity and mortality, packing densities as well as follow-up data is limited. Material and Methods We conducted a retrospective study to investigate differences in aneurysms stented with the Enterprise or Neuroform stents. Angiographic follow-up (mean 19.42 months) was available in 72.6% (61/84) of aneurysms treated with stent-assisted coiling. We further sought to compare stent-assisted coiling to a matched patient population with aneurysms treated by conventional coil embolization. Results The stenting success rate of the Enterprise was higher compared to the Neuroform stent (46/48 and 42/51, respectively). In 5 of 9 cases in which the Neuroform stent was not navigable to the landing zone, we successfully deployed an Enterprise stent instead. Eventually, 42 aneurysms were coiled after stenting in each group. We observed no significant differences in peri-procedural complication rate, post-procedural hospital stay, packing density, recurrence rate or number of in-stent stenosis. Strikingly, 36.1% of followed aneurysms in the SAC group showed progressive occlusion on angiographic follow-up imaging. The packing density was significantly higher in aneurysms treated by SAC as compared to conventionally coiled aneurysms, while recanalization rate was significantly lower in the SAC group. Conclusion The procedural success rate is higher using the Enterprise, but otherwise both stents exhibited similar characteristics. Lower recurrence frequency and complication rates comparable to conventional coil embolization emphasize the importance of stent-assisted coiling in the treatment of complex aneurysms. Progressive occlusion on angiographic follow-up was a distinct and frequent observation in the SAC group and may in part be due to flow diversion.

Occlusion Time for Amplatzer Vascular Plug in the Management of Pulmonary Arteriovenous Malformations

OBJECTIVE The occlusion time, that is, the interval between device deployment and complete occlusion of the vessel, associated with the use of embolic devices influences the risk of embolic complications caused by small clots that can form over the surface of a device and break away. The purpose of our study was to determine the time for an Amplatzer vascular plug to bring about percutaneous transcatheter occlusion of a pulmonary arteriovenous malformation (PAVM). MATERIALS AND METHODS We retrospectively studied the occlusion times of Amplatzer vascular plugs in the management of 12 PAVMs. We recorded the number, location, type (simple or complex), and diameter and number of feeding arteries of PAVMs; the number and size of devices needed to occlude each PAVM; and the occlusion time for each PAVM. The occlusion time is the time interval from device placement to complete occlusion of the PAVM. Occlusion time was determined by recording the time between acquisition of the first angiographic image after deployment of the device and the angiogram that showed total occlusion of the PAVM. The relevant literature on the subject was reviewed. RESULTS All PAVMs managed were supplied by a single feeding artery. The average diameter of the feeding arteries was 4.8 mm (range, 3.0-11.2 mm). All PAVMs were occluded by deployment of a single Amplatzer vascular plug. Vascular plug sizes ranged from 4 to 16 mm. The mean occlusion time was 3 minutes 20 seconds (range, 1 minute 49 seconds-5 minutes 16 seconds). There were no immediate complications, including air embolism and thromboembolism. CONCLUSION The occlusion time determined in our study and the need to place only one Amplatzer vascular plug in each feeding artery to achieve complete occlusion in most cases suggest that the device is safe for management of PAVM with no increased risk of systemic embolization. The use of the Amplatzer vascular plug for PAVM embolization is a relatively recent development. Long-term follow-up studies are needed to assess recanalization rates, radiation exposure rates, and risk of device migration.

Pre-intervention triage incorporating perfusion imaging improves outcomes in patients undergoing endovascular stroke therapy: a comparison with the device trials

Objectives Endovascular therapy of acute ischemic stroke is evolving towards thrombectomy devices for vessel recanalization. High rates of revascularization have been reported in stroke device trials. However, the discrepancy between recanalization and outcomes raises the question whether patients with irreversible ischemic injury are being exposed to these interventions. This study evaluated a triage methodology that incorporates perfusion imaging against previous device trials that treated all patients within a certain time frame. Methods 99 consecutive patients were identified with anterior circulation strokes who had undergone endovascular therapy. All patients had a baseline NIHSS score ≥8 and had undergone pre-intervention CT perfusion. Rates of recanalization and functional outcomes were compared with the MERCI, Multi-MERCI and Penumbra trials. Results This studys recanalization rate of 55.6% is not significantly different from the 46% for MERCI (p=0.15) and 68% for Multi-MERCI (p=0.08) but was significantly lower than the 82% for the Penumbra trial (p<0.0001). Successfully recanalized patients had a significantly higher good outcome of 67% in this cohort versus 46% in MERCI, 49% in Multi-MERCI and 29% in Penumbra. The rate of futile recanalization was 33% compared with 54% for MERCI, 51% for Multi-MERCI and 71% for Penumbra. A small cerebral blood volume (CBV) abnormality (p<0.0001) and large mean transit time–CBV mismatch (p<0.0001) were strong predictors of a good outcome. Conclusion Despite similar or lower recanalization rates, there was a significantly higher rate of good outcomes in the recanalized population and thus a significantly lower rate of futile recanalization in this study versus the device trials, suggesting a role for pre-intervention perfusion imaging for patient selection.

Endovascular therapy yields significantly superior outcomes for large vessel occlusions compared with intravenous thrombolysis: is it time to randomize?

Background and purpose We compared outcomes between endovascular (EV) therapy and intravenous (IV) thrombolysis in large vessel strokes. Methods 223 patients who had received either IV (n=100) or EV (n=123) therapy were analyzed. Only patients with strokes involving the internal carotid artery terminus (ICA-T, n=45), the middle cerebral artery (M1, n=107) or the bifurcation branches (M2, n=71) were included. The primary endpoint was 3 month outcome based on the modified Rankin Scale (mRS) score, good-outcome defined as mRS ≤2. Results The good outcome was 44.7% in the EV group and 26% in the IV group (p=0.003, OR 2.3, 95% CI 1.3 to 4.1). There was no difference in mortality or hemorrhage. For ICA-T occlusions, the good outcome was 27.6% in the EV and 0% in the IV group (p=0.004); for M1 occlusions, 40.6% in the EV versus 10.5% in the IV group (p=0.0006, OR 5.8, 95% CI 1.9 to 18.2); and for M2 occlusions, 76% in the EV versus 47.8% in the IV group (p=0.01, OR 3.5, 95% CI 1.2 to 10.2). For M1 occlusions, the death rate was 27.5% for the EV compared with 57.9% for the IV group (p=0.002, OR 3.6, 95% CI 1.6 to 8.3) with no difference observed in mortality for ICA-T or M2 occlusions. In the univariate analysis, age, National Institutes of Health Stroke Scale score and occlusion site were significant predictors of outcome and mortality (p<0.0001 for all). In the multivariable analysis, EV therapy (p=0.0004, OR 3.9, 95% CI 1.8 to 9) and younger age (p<0.0001, OR 0.96, 95% CI 0.9 to 0.98) were significant independent predictors of good outcome. Conclusions There are significantly higher odds of a favorable outcome with EV compared with IV therapy for large vessel strokes. The data support the rationale of a randomized trial for large vessel occlusions.

Pre-intervention cerebral blood volume predicts outcomes in patients undergoing endovascular therapy for acute ischemic stroke

Background Pre-intervention perfusion imaging is increasingly becoming part of stroke triage. Small studies supporting imaging based patient selection have been published. The goal of this larger study was to determine if perfusion imaging could impact on functional outcomes in patients undergoing stroke interventions. Methods All patients who had undergone endovascular therapy for anterior circulation strokes over a 7 year period were retrospectively analyzed. The pre-intervention perfusion imaging was assessed for size of cerebral blood volume (CBV), cerebral blood flow and mean transit time (MTT) abnormalities. A perfusion mismatch for irreversible versus reversible ischemia was based on CBV and MTT. Clinical outcome and mortality were based on the 90 day modified Rankin Scale. An analysis of the pre-intervention perfusion parameters was then performed to determine any impact on functional outcomes. Results 110 patients underwent endovascular therapy for anterior circulation strokes. A younger age and lower National Institutes of Health Stroke Scale score were important clinical predictors of favorable outcome (modified Rankin Scale ≤2). The extent of the CBV abnormality and percentage of CBV/MTT mismatch were the strongest imaging predictors of outcome and mortality. A CBV area of 229.5 mm2 (±290) was seen for favorable outcomes versus 968 mm2 (±1173) for poor outcomes (p<0.0001). A CBV/MTT mismatch of 91% (±10.7) was seen for favorable outcomes versus 72.5% (±31.6) for poor outcomes (p=0.0001). The CBV area was 273 mm2 (±392) in patients without mortality versus 1401.1 mm2 (±1310) in patients with mortality (p<0.0001). Patients who survived had a mean CBV/MTT mismatch of 90.2% (±12.5) versus 61.1% (±35.2) for those who did not (p<0.0001). A CBV lesion approximately greater than one-third of the middle cerebral artery distribution predicted a poor outcome and mortality. Conclusion The extent of pre-intervention CBV abnormality is a strong predictor of functional outcomes following endovascular stroke therapy. This information can aid in patient selection and improve procedure efficacy.

Endovascular treatment of extracranial atherosclerotic disease involving the vertebral artery origins: a comparison of drug-eluting and bare-metal stents

Objective To determine whether drug-eluting (DE) stents offer any advantage over bare-metal (BM) stents in terms of restenosis rates and to identify indications for vertebral artery stenting (VAS) based on the current literature. Methodology A retrospective analysis was performed for patients who underwent extracranial VAS for symptomatic stenosis. Patients were divided into two groups based on stent use (DE and BM). Results A total of 28 stents were implanted in 24 patients. Of these, 13 were DE and 15 BM. Technical success was achieved in all patients. There were procedure-related complications of retroperitoneal hematoma in some patients (3.6%). The median clinical and imaging follow-up times were 26 and 21 months, respectively, for the BM arm and 13 and 12 months, respectively, for the DE group. The mean stenosis percentage was 80.7±10.9 for the BM group and 87.0±9.5 for the DE group. The mean stent diameter was 4.7±0.5 for the BM group and 3.3±0.4 for the DE group (p<0.0001). There was no statistical difference in the restenosis rates among the two groups, 4/15 (26.7%) for BM and 4/13 (30.8%) for DE stents. Conclusions Extracranial VAS is a relatively safe procedure. No differences could be elicited in the restenosis rates between BM and DE stents. While VAS has been reported for symptomatic and asymptomatic disease, a benefit of VAS has only been demonstrated for patients with symptoms clearly attributable to the diseased artery. The benefit of stenting in asymptomatic disease or stenting to improve perfusion to the anterior circulation is speculative.

Pneumocele of the frontal sinus producing orbital roof defect: case report and review of literature

Type III frontal recess air cell as a cause of frontal sinus pneumocele has not been previously reported in literature. A 31-year-old woman with chronic history of sinusitis presented with pressure in the left eye on blowing the nose. Computed tomography examination of the orbits and paranasal sinuses with coronal and sagittal reformatted images showed abnormal collection of gas in the soft tissues at the superior aspect of the left orbit contiguous with the overlying left frontal sinus through a large defect in the orbital roof and a type III frontal recess air cell narrowing the left frontal recess.

CT perfusion imaging pitfall related to fetal posterior cerebral artery.

OBJECTIVE The purpose of this article is to discuss how a unilateral fetal posterior cerebral artery (PCA) causes perfusion map asymmetry due to anteroposterior bolus arrival discrepancy. We performed region of interest analysis of asymmetric perfusion maps before and after delay correction was performed. CONCLUSION Perfusion asymmetry becomes unapparent using a delay correction algorithm, indicating bolus arrival delay on the side opposite the fetal PCA. Delay correction algorithms can eliminate deconvolution errors related to bolus arrival delay.

Condylar jugular Diverticulum

We would like to present 6 instances of an internal jugular bulb diverticulum extending into the occipital condyle, which, to the best of our knowledge, has not been described in the English-language literature. This asymptomatic variant was detected incidentally on 6 patients. Computed tomography was performed on all 6 cases, and magnetic resonance imaging and magnetic resonance venography was performed in 2 cases. The condylar jugular diverticula presented as a well-defined defect in the occipital condyle contiguous with the jugular bulb on computed tomography. Magnetic resonance venography showed flow within the diverticulum. There was no definite relationship to a dominant transverse sinus. Recognition of this variant will help to avoid potential confusion with pathological lesions in the occipital condyle, especially on magnetic resonance imaging.

Isolated trochlear nerve (cranial nerve IV) palsy in a patient with carotid-cavernous fistula

Isolated fourth cranial (trochlear) nerve palsy is an uncommon occulomotor nerve palsy typically secondary to ischemia, inflammation/infection, or mass effect. Due to its positioning within the cavernous sinus, pathology of the deep cerebral venous system would theoretically predispose to palsy of this nerve. We present a case of a patient presenting with isolated trochlear nerve palsy in the setting of angiographically-confirmed direct carotid-cavernous fistula.