Stuart C. Coley

Complications of cerebral angiography: a prospective analysis of 2,924 consecutive procedures

IntroductionCerebral angiography is an invasive procedure associated with a small, but definite risk of neurological morbidity. In this study we sought to establish the nature and rate of complications at our institution among a large prospective cohort of consecutive patients. Also, the data were analysed in an attempt to identify risk factors for complications associated with catheter angiography.MethodsData were prospectively collected for a consecutive cohort of patients undergoing diagnostic cerebral angiography between January 2001 and May 2006. A total of 2,924 diagnostic cerebral angiography procedures were performed during this period. The following data were recorded for each procedure: date of procedure, patient age and sex, clinical indication, referring specialty, referral status (routine/emergency), operator, angiographic findings, and the nature of any clinical complication or asymptomatic adverse event (arterial dissection).ResultsClinical complications occurred in 23 (0.79%) of the angiographic procedures: 12 (0.41%) significant puncture-site haematomas, 10 (0.34%) transient neurological events, and 1 nonfatal reaction to contrast agent. There were no permanent neurological complications. Asymptomatic technical complications occurred in 13 (0.44%) of the angiographic procedures: 3 groin dissections and 10 dissections of the cervical vessels. No patient with a neck dissection suffered an immediate or delayed stroke. Emergency procedures (P = 0.0004) and angiography procedures performed for intracerebral haemorrhage (P = 0.02) and subarachnoid haemorrhage (P = 0.04) were associated with an increased risk of complications.ConclusionNeurological complications following cerebral angiography are rare (0.34%), but must be minimized by careful case selection and the prudent use of alternative noninvasive angiographic techniques, particularly in the acute setting. The low complication rate in this series was largely due to the favourable case mix.

Cerecyte Coil Trial Angiographic Outcomes of a Prospective Randomized Trial Comparing Endovascular Coiling of Cerebral Aneurysms With Either Cerecyte or Bare Platinum Coils

Background and Purpose— We report the primary outcome of the Cerecyte Coil Trial, a randomized trial to determine whether polymer-loaded Cerecyte coils compared with Micrus bare platinum coils improved the proportion of patients with angiographic occlusion of the aneurysm at 6 months when assessed by a core laboratory. The secondary objectives were to compare the clinical outcomes and retreatment rates in the 2 groups. Methods— Five hundred patients between 18 and 70 years of age with a ruptured or unruptured target aneurysm were randomized to be treated with either Cerecyte or bare platinum coils in 23 centers worldwide. Two hundred forty-nine patients were assigned to Cerecyte coils and 251 to bare platinum coils. Analysis was by intention to treat. Results— Four hundred ninety-four patients were eligible for analysis. Four hundred eighty-one patients underwent coil treatment of their aneurysm, 227 patients with recently ruptured aneurysms and 254 with unruptured aneurysms. Four hundred thirty-three follow-up angiograms were assessed by the core laboratory; 127 of 215 (59%) and 118 of 218 (54%) in the Cerecyte and bare platinum groups, respectively, fulfilled the trial prespecified definition of success, namely that the treated aneurysm showed complete angiographic occlusion, had stable neck remnant, or improved in angiographic appearance compared with the end-of-treatment angiogram (P=0.17). Late retreatment was performed in 25 of 452 (5.5%) patients, 17 (7.7%) Cerecyte versus 8 (3.5%) bare platinum (P=0.064; range, 4–34 months). The clinical outcomes did not differ between the groups. Conclusion— There was no significant difference at 6 months in the angiographic outcomes between Cerecyte coils and bare platinum coils when assessed by the core laboratory. Clinical Trial Registration Information— URL: www.controlled-trials.com. Unique Identifier: ISRCTN82461286.

Computational hemodynamics in cerebral aneurysms: the effects of modeled versus measured boundary conditions.

Modeling of flow in intracranial aneurysms (IAs) requires flow information at the model boundaries. In absence of patient-specific measurements, typical or modeled boundary conditions (BCs) are often used. This study investigates the effects of modeled versus patient-specific BCs on modeled hemodynamics within IAs. Computational fluid dynamics (CFD) models of five IAs were reconstructed from three-dimensional rotational angiography (3DRA). BCs were applied using in turn patient-specific phase-contrast-MR (pc-MR) measurements, a 1D-circulation model, and a physiologically coherent method based on local WSS at inlets. The Navier–Stokes equations were solved using the Ansys®-CFX™ software. Wall shear stress (WSS), oscillatory shear index (OSI), and other hemodynamic indices were computed. Differences in the values obtained with the three methods were analyzed using boxplot diagrams. Qualitative similarities were observed in the flow fields obtained with the three approaches. The quantitative comparison showed smaller discrepancies between pc-MR and 1D-model data, than those observed between pc-MR and WSS-scaled data. Discrepancies were reduced when indices were normalized to mean hemodynamic aneurysmal data. The strong similarities observed for the three BCs models suggest that vessel and aneurysm geometry have the strongest influence on aneurysmal hemodynamics. In absence of patient-specific BCs, a distributed circulation model may represent the best option when CFD is used for large cohort studies.

Cerecyte Coil Trial: Procedural Safety and Clinical Outcomes in Patients with Ruptured and Unruptured Intracranial Aneurysms

BACKGROUND AND PURPOSE: This study arose from a need to systematically evaluate the clinical and angiographic outcomes of intracranial aneurysms treated with modified coils. We report the procedural safety and clinical outcomes in a prospective randomized controlled trial of endovascular coiling for ruptured and unruptured intracranial aneurysms, comparing polymer-loaded Cerecyte coils with bare platinum coils in 23 centers worldwide. MATERIALS AND METHODS: Five hundred patients between 18 and 70 years of age with a ruptured or unruptured target aneurysm planning to undergo endovascular coiling were randomized to receive Cerecyte or bare platinum coils. Analysis was by intention to treat. RESULTS: Two hundred forty-nine patients were allocated to Cerecyte coils and 251 to bare platinum coils. Baseline characteristics were balanced. For ruptured aneurysms, in-hospital mortality was 2/114 (1.8%) with Cerecyte versus 0/119 (0%) bare platinum coils. There were 8 (3.4%) adverse procedural events resulting in neurological deterioration: 5/114 (4.4%) with Cerecyte versus 3/119 (2.5%) with bare platinum coils (P = .22). The 6-month mRS score of ≤2 was not significantly different in 103/109 (94.5%) patients with Cerecyte and 110/112 (98.2%) patients with bare platinum coils. Poor outcome (mRS score of ≥3 or death) was 6/109 (5.5%) with Cerecyte versus 2/112 (1.8%) with bare platinum coils (P = .070). For UIAs, there was no in-hospital mortality. There were 7 (2.7%) adverse procedural events with neurological deterioration, 5/133 (3.8%) with Cerecyte versus 2/131 (1.5%) with bare platinum coils (P = .13). There was a 6-month mRS score of ≤2 in 114/119 (95.8%) patients with Cerecyte versus 123/123 (100%) patients with bare platinum coils. There was poor outcome (mRS ≥3 and 1 death) in 5/119 (4.2%) patients with Cerecyte versus 0/123 (0%) patients with bare platinum coils (P = .011). CONCLUSIONS: There was a statistical excess of poor outcomes in the Cerecyte arm at discharge in the ruptured aneurysm group and at 6-month follow-up in the unruptured group. Overall adverse clinical outcomes and in-hospital mortality were exceptionally low in both groups.

Stereotactic radiosurgery for deep-seated cavernous malformations: a move toward more active, early intervention. Clinical article.

OBJECT The role of radiosurgery in the treatment of cavernous malformations (CMs) remains controversial. It is frequently recommended only for inoperable lesions that have bled at least twice. Rehemorrhage can carry a substantial risk of morbidity, however. The authors reviewed their practice of treating deep-seated inoperable CMs to assess the complication rate of radiosurgery, the impact that radiosurgery might have on rebleeding, and whether a more active, earlier intervention is justified in managing this condition. METHODS The authors performed a retrospective analysis of 113 patients with 79 brainstem and 39 thalamic/basal ganglia CMs treated with Gamma Knife surgery. Lesions were stratified into 2 groups: those that might be lower risk with no more than 1 symptomatic bleed before radiosurgical treatment and those deemed high risk with multiple symptomatic hemorrhages before treatment. RESULTS Forty-one CMs had multiple symptomatic hemorrhages before radiosurgery with a first-ever bleed rate of 2.9% per lesion per year, a rebleed rate of 30.5% per lesion per year, and a median time of 1.5 years between the first and second bleeds. In this group the rebleed rate decreased to 15% for the first 2 years after radiosurgery and declined further to 2.4% thereafter. Pretreatment multiple bleeds led to persistent deficits in 72% of the patients. Seventy-seven CMs had no more than 1 symptomatic bleed before radiosurgery, making for a lifetime bleed rate of 2.2% per lesion per year. The short period between the presenting bleed and treatment (median 1 year) makes the natural history in this group uncertain. The rate of hemorrhage in the first 2 years after treatment was 5.1%, and 1.3% thereafter. Pretreatment hemorrhages resulted in permanent deficits in 43% of the patients in this group, a rate significantly lower than in the multiple-bleeds group (p < 0.001). Posttreatment hemorrhages led to persistent deficits in only 7.3% of the patients. Permanent adverse radiation effects were rare (7.3%) and minor in both groups. CONCLUSIONS Stereotactic radiosurgery is a safe management strategy for CMs in eloquent sites with the marked advantage of reducing rebleed risks in patients with repeated pretreatment hemorrhages. The benefit in treating CMs with a single bleed is less clear. Note, however, that repeated hemorrhage carries a significant risk of increased morbidity far in excess of any radiosurgery-related morbidity, and the authors assert that this finding justifies the early active management of deep-seated CMs.

Effects of smoking and hypertension on wall shear stress and oscillatory shear index at the site of intracranial aneurysm formation.

OBJECTIVE The mechanisms by which smoking and hypertension lead to increased incidence of intracranial aneurysm (IA) formation remain poorly understood. The current study investigates the effects of these risk factors on wall shear stress (WSS) and oscillatory shear index (OSI) at the site of IA initiation. METHODS Two (n=2) IAs from two patients with history of smoking and hypertension were artificially removed with the help of software @neuFuse (Supercomputing Solutions, Bologna, Italy) and the vessel geometry reconstructed to mimic the condition prior to IA formation. Two computational fluid dynamics (CFD) analyses were performed on each data-set by using in turn the normal physiological values of blood viscosity (BV), and high BV values specific to smoking and hypertension, obtained from literature. RESULTS At normal BV, high WSS (>15 Pa) was observed at the site of IA initiation in both patients. When BV values specific to smoking and hypertension were used, both the areas affected by high WSS (>15 Pa) and the maximum WSS were increased whilst the magnitude and distribution of OSI showed no significant change. CONCLUSIONS Long-term exposure to high WSS may result in an increased risk of IA development. An incremental increase in areas of high WSS observed secondary to smoking and hypertension may indicate a further increase in the risk of IA initiation. Interestingly, the relationship between BV and the area of increased WSS was not linear, reflecting the need for patient-specific CFD analysis.

Neurovascular MRI with dynamic contrast-enhanced subtraction angiography

The first generation of digital subtraction MR angiography using thick-slab contrast-enhanced 2D projection techniques has confirmed the potential of MRI to produce noninvasive subsecond angiograms of the craniocervical circulation. As time-resolved techniques become more sophisticated and 3D acquisitions can be obtained with high isotropic spatial resolution we may start to see the demise of catheter angiography as a diagnostic procedure.

First-line investigation of acute intracerebral hemorrhage using dynamic magnetic resonance angiography:

Purpose: To report the initial experience of magnetic resonance (MR) digital subtraction angiography (MR-DSA) in the dynamic assessment of the cerebral circulation in acute non-traumatic intracerebral hemorrhage (ICH). Material and Methods: Twelve patients with acute ICH were investigated within 6 days of the ictus using a dynamic contrast-enhanced 2-D MR angiogram that produces subtracted images with a temporal resolution of 1–2 frame/s. The MR-DSA examinations were assessed for evidence of an intracranial vascular abnormality and were compared with (i) the routine MR sequences, (ii) non-dynamic time-of-flight MR angiography, and (iii) catheter angiogram performed during the same admission. Results: All 12 MR-DSA examinations were considered to be technically satisfactory. MR-DSA detected an intracranial vascular abnormality in 7 patients (3 arteriovenous malformations, 2 aneurysms, 1 dural arteriovenous fistula, and 1 venous thrombosis). All abnormalities were confirmed by catheter angiography with the exception of one patient with venous sinus thrombosis found on MR imaging that did not undergo catheter angiography. All four arteriovenous shunts were detected by MR-DSA by virtue of early venous filling. Conclusion: MR-DSA can be performed satisfactorily in the setting of acute ICH and provides an alternative method to catheter angiography for identifying shunting vascular abnormalities such as arteriovenous malformations and fistulae, as well as large aneurysms and venous occlusions. MR-DSA is a contrast-medium-based technique that does not suffer from the T1 shortening effects of acute hemorrhage that can obscure abnormalities on conventional flow-based non-dynamic techniques.

Stereotactic radiosurgery for arteriovenous malformations located in deep critical regions.

BACKGROUND Radiosurgery is widely used to treat deep eloquent arteriovenous malformations (AVMs). OBJECTIVE To evaluate how anatomic location, AVM size, and treatment parameters define outcome. METHODS Retrospective analysis of 356 thalamic/basal ganglia and 160 brainstem AVMs treated with gamma knife radiosurgery. RESULTS Median volume was 2 cm (range, 0.02-50) for supratentorial and 0.5 cm (range, 0.01-40) for brainstem AVMs; the marginal treatment doses were 17.5 to 25 Gy. After single treatment, obliteration was achieved in 65% of the brainstem, in 69% of the supratentorial, and 40% of the peritectal AVMs. Obliteration of lesions <4 cm was better in the brainstem (70%) and in the supratentorium (80%), but not in the peritectal region (40%). Complications were rare (6%-15%) and mild (≤ modified Rankin scale [MRS] 2). Rebleed rate increased with size, but was not higher than before treatment. AVMs >4 cm in the brainstem were treated with unacceptable morbidity and low cure rate. Obliteration of large supratentorial AVMs was 65% to 47% with more complications ≥ MRS3. Repeat radiosurgical treatment led to obliteration in 66% of the cases with minor morbidity. CONCLUSION Deep eloquent AVMs <4 cm can be treated safely and effectively with radiosurgery. Obliteration of peritectal AVMs is significantly lower after a single treatment. However, morbidity is low, and repeat treatment leads to good obliteration. Radiosurgical treatment >4 cm in the brainstem is not recommended. Supratentorial deep AVMs >8 cm can be treated with radiosurgery with higher risk and lower obliteration rate. However, these lesions are difficult to treat with other treatment modalities, and a 50% success rate makes radiosurgery a good alternative even in this challenging group.

3.0 T MRI of 2000 consecutive patients with localisation-related epilepsy

OBJECTIVES Clinical guidelines suggest that all patients diagnosed with localised seizures should be investigated with MRI to identify any epileptogenic structural lesions, as these patients may benefit from surgical resection. There is growing impetus to use higher field strength scanners to image such patients, as some evidence suggests that they improve detection rates. We set out to review the detection rate of radiological abnormalities found by imaging patients with localised seizures using a high-resolution 3.0 T epilepsy protocol. METHODS Data were reviewed from 2000 consecutive adult patients with localisation-related epilepsy referred between January 2005 and February 2011, and imaged at 3.0 T using a standard epilepsy protocol. RESULTS An abnormality likely to be related to seizure activity was identified in 403/2000 (20.2%) patients, with mesial temporal sclerosis diagnosed in 211 patients. 313/2000 (15.6%) had lesions potentially amenable to surgery. Abnormalities thought unrelated to seizure activity were found in 324/2000 (16.1%), with 8.9% having evidence of ischaemic disease. CONCLUSIONS Since the introduction of the then National Institute for Clinical Excellence guidelines in 2004, the detection rate of significant pathology using a dedicated 3.0 T epilepsy protocol has not fallen, despite the increased numbers of patients being imaged. This is the largest study of epilepsy imaging at 3.0 T to date and highlights the detection rates of significant pathology in a clinical setting using a high-strength magnet. The prevalence of ischaemic disease in this population is significantly higher than first thought, and may not be incidental, as is often reported.