Complications in cerebral angiography with iohexol (Omnipaque) and meglumine metrizoate (Isopaque cerebral)

Iopentol Compared with Iohexol in Carotid Angiography

A randomized double blind crossover test with iohexol and the new non-ionic contrast medium iopentol in 12 patients undergoing carotid angiography showed no difference in tolerability, EEG, ECG, neurologic status or image quality. Iopentol seems to be well suited for cerebral angiography.

Cerebral Panangiography in Spontaneous Subarachnoid Hemorrhage from Intracranial Aneurysms

Cerebral panangiography was performed in 594 patients with subarachnoid hemorrhage from intracranial aneurysms. Aneurysm of the middle cerebral arteries was the most frequent location of aneurysms in this material. Multiple aneurysms of the middle cerebral arteries are far more frequent than the combination of other locations. Judged from this material there is a 7 per cent possibility of finding a contralateral aneurysm of the middle cerebral arteries if one is found. Multiple aneurysms were found in 51 (8.6%) of the 594 patients. We conclude that the results of this study are typical for Norwegians, although some selection exists since the patients were first admitted to other hospitals. The frequency of complications with cerebral panangiography in subarachnoid hemorrhage was less than that of cerebral angiography in patients with other diseases.

Increased risk for complications following diagnostic cerebral angiography in older patients: Trends from the Nationwide Inpatient Sample (1999-2009)

The full utility of diagnostic cerebral angiography, an invasive cerebrovascular imaging technique, is currently debated. Our goal was to determine trends in diagnostic cerebral angiography utilization and associated complications from 1999 through 2009. The National Inpatient Sample (NIS) was used to identify patients who received primary cerebral angiography from 1999-2009 in the United States. We observed trends in discharge volume, total mean charge, and post-procedural complications for this population. Data was based on sample projections and analyzed using univariate and multivariate regression. There were a total of 424,105 discharges indicating primary cerebral angiography nationwide from 1999-2009. The majority of these cases (65%) were in patients older than 55years. Embolic stroke was the most frequent complication, particularly in the oldest age bracket, occurring in 16,304 patients. The risk for complications increased with age (p<0.0001) and with other underlying health conditions. Pulmonary, deep vein thrombosis, and renal associated comorbidities resulted in the greatest risk for developing post-procedural complications. Throughout the study period case volume for cerebral angiography remained constant while total charge per patient increased from $17,365 in 1999 to $45,339 in 2009 (p<0.001). While the overall complication rate for this invasive procedure is relatively low, the potential risk for embolic stroke in older patients is significant. It is worth considering less invasive diagnostic techniques for an older and at risk patient population.

Pitfalls and complications management in the endovascular treatment of aneurysms

This article reviews complications associated with the endovascular management of intracranial aneurysms, focusing on risk factors, avoidance, recognition, and management. Such complications can be devastating. Both neurologic and nonneurologic complications can occur. Several patient and procedure related parameters can increase the incidence of complications. Reduction of complication rates can be achieved by careful patient selection, meticulous planning and preparation for the procedure, anticipating potential complications, and preparing for their management. Tracking outcomes and a robust case conference can further enhance outcomes. Education of the care team and a collaborative environment can foster greater focus on avoidance of complications.

WebParc: a tool for analysis of the topography and volume of stroke from MRI

The quantitative assessment of the anatomic consequences of cerebral infarction is critical in the study of the etiology and therapeutic response in patients with stroke. We present here an overview of the operation of "WebParc," a computational system that provides measures of stroke lesion volume and location with respect to canonical forebrain neural systems nomenclature. Using a web-based interface, clinical imaging data can be registered to a template brain that contains a comprehensive set of anatomic structures. Upon delineation of the lesion, we can express the size and localization of the lesion in terms of the regions that are intersected within the template. We demonstrate the application of the system using MRI-based diffusion-weighted imaging and document measures of the validity and reliability of its uses. Intra- and inter-rater reliability is demonstrated, and characterized relative to the various classes of anatomic regions that can be assessed. The WebParc system has been developed to meet criteria of both efficiency and intuitive operator use in the real time analysis of stroke anatomy, so as to be useful in support of clinical care and clinical research studies. This article is an overview of its base-line operation with quantitative anatomic characterization of lesion size and location in terms of stroke distribution within the separate gray and white matter compartments of the brain.

[Recent studies concerning treatment of acute, ischemic infarcts]

This article gives an overview over past and present studies concerning the acute management of stroke. Stroke trials involving intra-arterial thrombolytic agents, either alone or in combination with other therapies, are described.

Trial design and reporting standards for intra-arterial cerebral thrombolysis for acute ischemic stroke

BACKGROUND AND PURPOSE

The National Institutes of Health (NIH) estimates that stroke costs now exceed 45 billion dollars per year. Stroke is the third leading cause of death and one of the leading causes of adult disability in North America, Europe, and Asia. A number of well-designed randomized stroke trials and case series have now been reported in the literature to evaluate the safety and efficacy of thrombolytic therapy for the treatment of acute ischemic stroke. These stroke trials have included intravenous studies, intra-arterial studies, and combinations of both, as well as use of mechanical devices for removal of thromboemboli and of neuroprotectant drugs, alone or in combination with thrombolytic therapy. At this time, the only therapy demonstrated to improve outcomes from an acute stroke is thrombolysis of the clot responsible for the ischemic event. There is room for improvement in stroke lysis studies. Divergent criteria, with disparate reporting standards and definitions, have made direct comparisons between stroke trials difficult to compare and contrast in terms of overall patient outcomes and efficacy of treatment. There is a need for more uniform definitions of multiple variables such as collateral flow, degree of recanalization, assessment of perfusion, and infarct size. In addition, there are multiple unanswered questions that require further investigation, in particular, questions as to which patients are best treated with thrombolysis. One of the most important predictors of clinical success is time to treatment, with early treatment of <3 hours for intravenous tissue plasminogen activator and <6 hours for intra-arterial thrombolysis demonstrating significant improvement in terms of 90-day clinical outcome and reduced cerebral hemorrhage. It is possible that improved imaging that identifies the ischemic penumbra and distinguishes it from irreversibly infarcted tissue will more accurately select patients for therapy than duration of symptoms. There are additional problems in the assessment of patients eligible for thrombolysis. These include being able to predict whether a particular site of occlusion can be successfully revascularized, predict an individual patient's prognosis and outcome after revascularization, and in particular, to predict the development of intracerebral hemorrhage, with and without clinical deterioration. It is not clear to assume that achieving immediate flow restoration due to thrombolytic therapy implies clinical success and improved outcome. There is no simple correlation between recanalization and observed clinical benefit in all ischemic stroke patients, because other interactive variables, such as collateral circulation, the ischemic penumbra, lesion location and extent, time to treatment, and hemorrhagic conversion, are all interrelated to outcome.

METHODS

This article was written under the auspices of the Technology Assessment Committees for both the American Society of Interventional and Therapeutic Neuroradiology and the Society of Interventional Radiology. The purpose of this document is to provide guidance for the ongoing study design of trials of intra-arterial cerebral thrombolysis in acute ischemic stroke. It serves as a background for the intra-arterial thrombolytic trials in North America and Europe, discusses limitations of thrombolytic therapy, defines predictors for success, and offers the rationale for the different considerations that might be important during the design of a clinical trial for intra-arterial thrombolysis in acute stroke. Included in this guidance document are suggestions for uniform reporting standards for such trials. These definitions and standards are mainly intended for research trials; however, they should also be helpful in clinical practice and applicable to all publications. This article serves to standardize reporting terminology and includes pretreatment assessment, neurologic evaluation with the NIH Stroke Scale score, imaging evaluation, occlusion sites, perfusion grades, follow-up imaging studies, and neurologic assessments. Moreover, previously used and established definitions for patient selection, outcome assessment, and data analysis are provided, with some possible variations on specific end points. This document is therefore targeted to help an investigator to critically review the scales and scores used previously in stroke trials. This article also seeks to standardize patient selection for treatment based on neurologic condition at presentation, baseline imaging studies, and utilization of standardized inclusion/exclusion criteria. It defines outcomes from therapy in phase I, II, and III studies. Statistical approaches are presented for analyzing outcomes from prospective, randomized trials with both primary and secondary variable analysis. A discussion on techniques for angiography, intra-arterial thrombolysis, anticoagulation, adjuvant therapy, and patient management after therapy is given, as well as recommendations for posttreatment evaluation, duration of follow-up, and reporting of disability outcomes. Imaging assessment before and after treatment is given. In the past, noncontrast CT brain scans were used as the initial screening examination of choice to exclude cerebral hemorrhage. However, it is now possible to quantify the volume of early infarct by using contiguous, discrete (nonhelical) images of 5 mm. In addition, CT angiography by helical scanning and 100 mL of intravenous contrast agent can be used expeditiously to obtain excellent vascular anatomy, define the occlusion site, obtain 2D and 3D reformatted vascular images, grade collateral blood flow, and perform tissue-perfusion studies to define transit times of a contrast bolus through specific tissue beds and regions of interest in the brain. Dynamic CT perfusion scans to assess the whole dynamics of a contrast agent transit curve can now be routinely obtained at many hospitals involved in these studies. The rationale, current status of this technology, and potential use in future clinical trials are given. Many hospitals are also performing MR brain studies at baseline in addition to, or instead of, CT scans. MRI has a high sensitivity and specificity for the diagnosis of ischemic stroke in the first several hours from symptom onset, identifies arterial occlusions, and characterizes ischemic pathology noninvasively. Case series have demonstrated and characterized the early detection of intraparenchymal hemorrhage and subarachnoid hemorrhage by MRI. Echo planar images, used for diffusion MRI and, in particular, perfusion MRI are inherently sensitive for the susceptibility changes caused by intraparenchymal blood products. Consequently, MRI has replaced CT to rule out acute hemorrhage in some centers. The rationale and the potential uses of MR scanning are provided. In addition to established criteria, technology is continuously evolving, and imaging techniques have been introduced that offer new insights into the pathophysiology of acute ischemic stroke. For example, a better patient stratification might be possible if CT and/or MRI brain scans are used not only as exclusion criteria but also to provide individual inclusion and exclusion criteria based on tissue physiology. Imaging techniques might also be used as a surrogate outcome measure in future thrombolytic trials. The context of a controlled study is the best environment to validate emerging imaging and treatment techniques. The final section details reporting standards for complications and adverse outcomes; defines serious adverse events, adverse events, and unanticipated adverse events; and describes severity of complications and their relation to treatment groups. Recommendations are made regarding comparing treatment groups, randomization and blinding, intention-to-treat analysis, quality-of-life analysis, and efficacy analysis. This document concludes with an analysis of general costs associated with therapy, a discussion regarding entry criteria, outcome measures, and the variability of assessment of the different stroke scales currently used in the literature is also featured.

CONCLUSIONS

In summary, this article serves to provide a more uniform set of criteria for clinical trials and reporting outcomes used in designing stroke trials involving intra-arterial thrombolytic agents, either alone or in combination with other therapies. It is anticipated that by having a more uniform set of reporting standards, more meaningful analysis of the data and the literature will be able to be achieved.

Neurologic complications of cerebral angiography: prospective analysis of 2,899 procedures and review of the literature

PURPOSE

To prospectively identify risk factors for neurologic complications related to cerebral angiography.

MATERIALS AND METHODS

A total of 2,899 consecutive cerebral digital subtraction angiograms obtained with nonionic contrast material were prospectively evaluated. Neurologic complications were categorized as transient (<24 hours), reversible (24 hours to 7 days), and permanent (>7 days). The neurologic complication rate was correlated with patient age, type of indication for catheter angiography, medical history, fluoroscopic time, number and size of catheters, type and number of vessels injected, operator experience, and the quartile in which the study was performed. The correlations were statistically analyzed with Fisher exact tests and a multiple logistic regression model.

RESULTS

There were 39 (1.3%) neurologic complications in 2,899 procedures; 20 were transient (0.7%), five (0.2%) were reversible, and 14 (0.5%) were permanent. Neurologic complications were significantly more common in patients 55 years of age or older (25 of 1,361; 1.8%) (P =.035), in patients with cardiovascular disease (CVD) (20 of 862; 2.3%) (P =.004), and when fluoroscopic times were 10 minutes or longer (24 of 1,238; 1.9%) (P =.022). The neurologic complication rate was higher in procedures performed by fellows alone (24 of 1,878; 1.3%) compared with that when staff alone performed the procedures (three of 598; 0.5%), but the difference was not significant (P =.172). Neurologic complications were lower in the fourth quartile of the study (six of 171; 0.9%) compared with the first quartile (16 of 776; 2.1%), which was likely due to fewer patients being examined for carotid stenosis or ischemic stroke and fewer patients with CVD (P =.085).

CONCLUSION

Age-related vascular disease accounted for the failure to lower the neurologic complication rate of cerebral angiography despite technical advances.

Effects of ionic and nonionic contrast media on endothelium and on arterial thrombus formation

BACKGROUND

The aims of the present study were to investigate whether ionic and nonionic contrast media (CM) affect: 1) the procoagulant and fibrinolytic activities of cultured human vessel endothelium; and 2) early events of tissue-factor-induced arterial thrombus formation under conditions which may follow a percutaneous transluminal coronary angioplasty (PTCA) procedure. The following 3 CM were studied: iohexol (nonionic monomer, Omnipaque); iodixanol (nonionic dimer, Visipaque); and ioxaglate (ionic dimer, Hexabrix). Saline (0.9%) and glucose (40 vol%) were used as control.

METHODS AND RESULTS

Exposing endothelium to 40 vol% CM for 10 min did not affect the selected parameters of cellular procoagulant (tissue factor), anticoagulant (thrombomodulin), fibrinolytic (tissue plasminogen activator) or antifibrinolytic (plasminogen activator inhibitor-1) activity or antigen. However, ioxaglate had a profound impact on the cell morphology, which was noted already after one minute of exposure. The cells contracted and rounded, exposing large areas of extracellular matrix. Iohexol showed this phenomenon to a considerably lesser extent, whereas iodixanol induced a slight swelling of the cells without detectable exposure of extracellular matrix. The effect of the respective CM on tissue-factor-driven thrombus formation at an arterial shear rate of 2600 s-1 was studied in an ex vivo parallel-plate perfusion chamber device. In this model, human native blood was passed over a tissue factor/phospholipid-rich surface following 30 s exposure to 100% CM. The CM was washed out by nonanticoagulated blood drawn directly from an antecubital vein by a pump positioned distal to the perfusion chamber. Such a pre-exposure of the procoagulant surface to iodixanol reduced the fibrin deposition around the platelet thrombi by 50% (p<0.01). However, iohexol and ioxaglate did not affect fibrin deposition. None of the 3 CM affected the recruitment of platelets in the thrombi, since similar values were obtained with pre-exposure to 40 vol% of saline.

CONCLUSION

Iodixanol appears to be most biocompatible with endothelium, and has a moderate inhibitory effect on fibrin deposition in flowing blood. This differs from iohexol, and in particular from ioxaglate, which induce endothelial changes in morphology with no effect on fibrin deposition. Since none of the CM affected the platelet aggregate formation, and since ioxaglate has been reported to have stronger anticoagulant and antithrombotic properties than iodixanol or iohexol in in vitro assays, it is apparent that these properties were not reflected in thrombus formation under the experimental conditions of high arterial shear.

Patients with polycystic kidney disease would benefit from routine magnetic resonance angiographic screening for intracerebral aneurysms: a decision analysis

Autosomal dominant polycystic kidney disease (ADPKD) is associated with increased prevalence of cerebral aneurysms and increased risk of subarachnoid hemorrhage. A decision analysis by Levey et al. in 1983 demonstrated that patients with ADPKD would not significantly benefit from routine arteriographic screening for cerebral aneurysms. We reexamined this conclusion in light of new clinical data and the introduction of magnetic resonance imaging (MRI) as a screening method. We compared an MRI screening strategy with a nonscreening strategy. The screening strategy specified MRI screening and then neurosurgical management of detected aneurysms. The nonscreening strategy specified cerebrovascular care only in the event of subarachnoid hemorrhage. The decision tree incorporated estimates derived from the clinical literature for the prevalence of asymptomatic aneurysms in patients with ADPKD (15%), the annual incidence of aneurysmal rupture (1.6%), the morbidity and mortality rates associated with subarachnoid hemorrhage (70 and 56%, respectively), the risk of transfemoral arteriography (0.2%), the sensitivity and specificity of MRI, the morbidity and mortality rates associated with surgical treatment of an unruptured aneurysm (4.1 and 1.0%, respectively), and the life expectancy of patients with ADPKD. The model predicted that the screening strategy would provide 1.0 additional year of life without neurological disability to a 20-year-old patient with ADPKD. A sensitivity analysis showed that the model was most sensitive to estimates of the prevalence of aneurysms in ADPKD, the annual incidence of rupture, and the morbidity and mortality rates associated with rupture. A financial analysis showed that a screening strategy is likely to cost less than a nonscreening strategy. The model predicts that an MRI screening strategy would increase the life expectancy of young patients with ADPKD and reduce the financial impact on society of ADPKD.

Cerebral angiographic risk in mild cerebrovascular disease

We review the eight prospective and seven retrospective studies from which it is possible to derive the complication rate of conventional cerebral angiography for patients with mild ischemic cerebrovascular disease who are potential candidates for carotid endarterectomy. Three studies of intravenous and one of intra-arterial digital subtraction angiography are also examined. An overview of the results suggests that the risk of a neurological complication (TIA or stroke) is about 4% and that a permanent neurological deficit (disabling stroke) occurs in about 1%. The mortality rate is very low (less than 0.1%). Systemic complications are not infrequent, particularly with intravenous digital subtraction angiography. The complication rate of cerebral angiography must be considered when evaluating the risks of carotid endarterectomy in patients with ischemic cerebrovascular disease.

Digital subtraction angiography (DSA). Work load and financial implications for a neuroradiology department

A four year study has been undertaken into the effects on the workload and cost implications of the introduction of digital subtraction angiography (DSA) in a large United Kingdom teaching hospital. The increase in workload has been entirely due to the ability to perform intravenous angiography. DSA is cheaper than conventional angiography if more than 210 cases are undertaken each year. This difference is accounted for by the reduced use of X-ray film. However, intravenous angiography is more expensive because of the use of large volumes of nonionic medium.