Cerebral complications of angiography for transient ischemia and stroke: prediction of risk

Surgical Techniques from Intraoperative Angiographic and Velocimetric Controls in 43 Consecutive Carotid Bifurcation Endarterectomies

From January to November, 1985, 43 carotid bifurcation endarterectomies (CE) were performed with intraoperative functional (Doppler spectrum analy sis) and morphologic (angiography) controls.

In the first 20 cases, after thromboendarterectomy and direct suture, Dop pler showed absence of or no significant variations of frequency in 17 cases, a frequency increase corresponding to a less than 45% diameter reduction steno sis at the apex of the suture in 2 cases, and no flow in the internal carotid artery (ICA) in 1 case. Angiography confirmed the thrombosis in the above mentioned case and showed 3 less than 50% stenoses at the distal end of the arteriotomy: 2 already recognized by Doppler in small-size ICAs and 1 in a medium-size ICA without significant changes of flow. The reason for thrombosis was a distal intimal flap, which was successfully removed; the 2 stenoses in which Doppler and angiography agreed were corrected by patch angioplasty. In the last 23 cases, patch angioplasty was performed routinely in small-size ICAs (6 cases); in 1 case, first treated by a direct suture, Doppler and angiography showed a medium-grade stenosis, immediately corrected; in 1 case both techniques showed a 50% stenosis in a common carotid artery, immediately corrected. The execution of intraoperative angiography in this group of patients al lowed the authors to define the indication for the use of patch angioplasty, never previously employed. Nevertheless, the authors state that, on account of loss of time, costs, and exposure to radiations, intraoperative angiography must be reserved for those cases selected by Doppler spectrum analysis. This method seems to be highly sensitive in recognizing significant technical defects that could lead to an immediate or late failure.

Assessment of Complication Types and Rates Related to Diagnostic Angiography and Interventional Neuroradiologic Procedures

We determined the types and rates of complications related to diagnostic angiography and neuroradiologic interventional procedures at a centre that carries out the full spectrum of angiographic procedures.

The occurrence of immediate and delayed complications in 1929 neuroangiographic procedures (1358 diagnostic and 571 interventional) performed between the years 1993–1996 was prospectively identified and recorded on a daily basis. A retrospective review of all charts of patients having procedures conducted during the study period was also carried out to ensure that no complications were missed.

The overall complication rate for diagnostic cerebral angiography was 2.2%. Puncture site complications ranged from 0 – 0.1%. Vessel injury distal to the puncture site ranged from 0.2 – 0.6%. The temporary neurologic complication rate was 0.3%, while the permanent rate was 0.4%. There were no contrast reactions. The death rate was 0.1%. Interventional procedures had higher incidences of complications with overall rates ranging from 5.3 – 33%. Temporary and permanent neurologic deficits occurred at a rate of 0 – 10.5% depending upon the procedure involved. Individual complication and death rates and complication categories are provided for arteriovenous malformation embolisation, tumour embolisation, temporary balloon occlusion tests, detachable balloon vessel sacrifice, urokinase infusion, angioplasty, papavarine infusion, GDC embolisation, and carotid cavernous fistula embolisation.

When carried out in experienced hands, neuroangiography and neurointervention are relatively safe with low incidences of neurologic and non-neurologic complications. Knowledge of these rates is important when counselling patients prior to treatments or deciding upon the risk-benefit ratio of preoperative procedures.

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.

Complications of preoperative balloon test occlusion of the internal carotid arteries: experience in 300 cases

Treatment of some tumors and aneurysms of the skull base may require internal carotid artery (ICA) sacrifice. Preoperatively to determine the dependence of the cerebral blood flow on a particular vessel, we perform a balloon test occlusion (BTO) by temporarily occluding the vessel in an awake patient. During occlusion, clinical evaluations and cerebral blood flow measurements are assessed. We have performed 300 BTOs. Eleven patients (3.7%) have had complications. Six (2%) were asymptomatic dissections. Five (1.7%) had neurologic deficits that persisted beyond the test period. Of these five, one was back to baseline in less than 24 hours, one recovered completely in a week, and one (0.33%) had a minimal but persistent dysphasia. These latter three cases are unexplained but might have resulted from unrecognized dissections or embolic events. Finally, one patient with a persistent deficit required energency surgery for reasons unrelated to the BTO and was therefore difficult to assess, and one required emergency middle cerebral artery embolectomy and repair of the dissection. The preoperative knowledge of carotid dependence in cases in which the ICA is at risk is essential, since vascular grafts or alternative surgical approaches are necessary in patients unable to tolerate carotid sacrifice. Since approximately 15 to 20% of the population falls into this category, a preoperative BTO appears justified.

Endovascular retrograde suction decompression as an adjunct to surgical treatment of ophthalmic aneurysms: analysis of risks and clinical outcomes

OBJECTIVE

Endovascular retrograde suction decompression with balloon occlusion of the internal carotid artery is a useful adjunct in the surgical treatment of ophthalmic aneurysms. This technique helps establish proximal control, facilitates intraoperative angiography, and may aid dissection by evacuating blood and softening the aneurysm. Although the technical aspects of this procedure have been described, the published data on its safety are scant. This study analyzed 2 groups of patients who underwent craniotomies for treatment of ophthalmic aneurysms, comparing a group who received suction decompression with a group who did not.

METHODS

A retrospective analysis of prospectively collected data on 118 craniotomies for ophthalmic aneurysms performed from 1990 to 2005 is presented. A group of 63 patients treated with endovascular suction decompression during surgery is compared with 55 patients who did not undergo this technique.

RESULTS

In our overall analysis of ophthalmic aneurysms, the clinical outcome was statistically related to aneurysm size (P = 0.046). The endovascular suction decompression group in this study had overall larger aneurysms (P < 0.0001) compared with the other group. There was no statistical difference between the 2 groups in rates of complications, stroke, new visual deficit, or death. The clinical outcomes were statistically similar at discharge and at 1 year.

CONCLUSION

Endovascular balloon occlusion and suction decompression did not increase the complication rate in a large cohort of craniotomy patients with ophthalmic aneurysms. This technique may be used to augment surgical capabilities without significantly increasing the operative risk.

Assessment of brain aneurysms by using high-resolution magnetic resonance angiography after endovascular coil delivery

OBJECT

Digital subtraction (DS) angiography is the current gold standard of assessing intracranial aneurysms after coil placement. Magnetic resonance (MR) angiography offers a noninvasive, low-risk alternative, but its accuracy in delineating coil-treated aneurysms remains uncertain. The objective of this study, therefore, is to compare a high-resolution MR angiography protocol relative to DS angiography for the evaluation of coil-treated aneurysms.

METHODS

In 2003, the authors initiated a prospective protocol of following up patients with coil-treated brain aneurysms using both 1.5-tesla gadolinium-enhanced MR angiography and biplanar DS angiography. Using acquired images, the subject aneurysm was independently scored for degree of remnant identified (complete obliteration, residual neck, or residual aneurysm) and the surgeon's ability to visualize the parent vessel (excellent, fair, or poor).

RESULTS

Thirty-seven patients with 42 coil-treated aneurysms were enrolled for a total of 44 paired MR angiography-DS angiography tests (median 9 days between tests). An excellent correlation was found between DS and MR angiography for assessing any residual aneurysm, but not for visualizing the parent vessel (K = 0.86 for residual aneurysm and 0.10 for parent vessel visualization). Paramagnetic artifact from the coil mass was minimal, and in some cases MR angiography identified contrast permeation into the coil mass not revealed by DS angiography. An intravascular microstent typically impeded proper visualization of the parent vessel on MR angiography.

CONCLUSIONS

Magnetic resonance angiography is a noninvasive and safe means of follow-up review for patients with coil-treated brain aneurysms. Compared with DS angiography, MR angiography accurately delineates residual aneurysm necks and parent vessel patency (in the absence of a stent), and offers superior visualization of contrast filling within the coil mass. Use of MR angiography may obviate the need for routine diagnostic DS angiography in select patients.

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.

B-mode ultrasound and spiral CT for the assessment of carotid atherosclerosis

More studies on the natural history of carotid artery plaques are needed to predict more reliably which plaque types or features are the most dangerous (see Table 2). Studies on carotid and coronary endarterectomy specimens indicate a dynamic process of rupture, thrombus formation, healing, and remodeling of the plaque. A plaque from a symptomatic patient may not show any signs of plaque rupture if the plaque has healed or evolved since the debut of symptoms. Selection of high-risk symptomatic patients with carotid atherosclerosis for medical or surgical treatment requires reliable, noninvasive, and cost-effective imaging methods. B-mode ultrasonography can be used for detection of early (IMT) as well as late (plaque morphology) atherosclerotic disease. Plaque morphology evaluation on spiral CT imaging is only for research and not yet for clinical use. Asymptomatic patients with carotid atherosclerosis hardly benefit from surgical treatment, as the minimal decrease in ischemic stroke risk is almost equal to the risk of perioperative stroke or death. A high degree of carotid stenosis measured using conventional angiography is an accepted risk factor for stroke but does not identify all vulnerable plaques. Echolucency on ultrasound B-mode imaging can be included as an important parameter in this risk stratification, as it appears to predict rupture-prone, lipid-rich plaques in the mild to severely stenotic carotid artery of a symptomatic patient. The subjective evaluation of plaque morphology on B-mode ultrasound should be complemented or substituted with objective evaluation such as videodensitometric analysis. This method is commercially available and is a relatively cheap and investigator-independent solution, but more studies are required to determine the exact contribution of echolucency to stroke risk. Furthermore, the evaluation of plaque morphology using ultrasound B-mode is still subject to large variations and observer-dependence, limiting its clinical use. In contrast, carotid IMT measurements are reliable to monitor progression and regression of early carotid disease as well as the impact of interventions. This method, however, suffers when used in severely diseased vessels where the boundaries of the IMT complex are hard to distinguish in all segments of the artery. Spiral CT imaging is a preliminary test for plaque characterization, as it primarily identifies calcification but not the more relevant lipid component. Moreover, it is time and resource demanding and involves use of both contrast and radiation, increasing the risk of allergic events and cancer. Standardization and continuous quality control are important, as are consensus agreements on how to quantify lesions (especially IMT), calibrate and standardize B-mode images and outline the plaque, and analyze data. The development of imaging methods for atherosclerotic research is currently fast and promising. This progress is most necessary, considering the very high demands for surrogate endpoints and risk markers in clinical intervention studies. Whether ultrasonic plaque characterization can be implemented in broad general clinical practice, for example, in screening of individuals at high risk of developing atherosclerosis and ischemic events, has to be based upon data from large prospective studies with long-term follow-up. IMT is already used in population screening, as in the ARIC study [9,101].

Carotid and cerebral angiography performed by cardiologists: cerebrovascular complications

The management of extracranial carotid artery disease is primarily concerned with the prevention of acute stroke. In order to understand the current risks of carotid angiography performed by interventional cardiologists, we undertook a retrospective study to determine the neurologic complications in patients who underwent selective cerebral angiography. All patients undergoing studies that were limited to diagnostic aortic arch angiography and selective four-vessel cerebral angiography in the cardiac catheterization laboratories during the past 6 years were included in this study. Hospital records were reviewed to determine any in-hospital cerebrovascular complications following carotid angiography, ranging from transient ischemic attack to major disabling stroke or death. A total of 189 consecutive patients underwent 191 diagnostic studies limited to aortic arch and four-vessel cerebral angiography in the cardiac catheterization laboratories between 1 January 1995 and 31 December 2000. Only one (0.52%) neurological complication, a minor stroke, occurred in our study population. There were no transient ischemic attacks, major strokes, or death. We have shown that experienced interventional cardiologists can perform diagnostic aortic arch and selective carotid and vertebral angiography in a cardiac catheterization laboratory with a very low complication rate. Because the risks of angiography add to those of revascularization of the carotid artery, the most highly skilled angiographer, regardless of primary specialty, should perform these studies.

Risks and benefits of diagnostic angiography after aneurysm surgery: a retrospective analysis of 597 studies

INTRODUCTION

Cerebral angiography performed after aneurysm surgery can identify causes of morbidity and mortality that may be corrected. The risks and benefits of angiography that is performed after aneurysm surgery, however, have not been clearly defined. We therefore reviewed our experience with postoperative angiography to determine its dangers and benefits.

METHODS

During 10 years, 543 consecutive patients received treatment for cerebral aneurysms. A retrospective analysis of 597 diagnostic angiograms obtained after aneurysm surgery for 494 of these patients was performed.

RESULTS

Catheter-induced vessel spasm and dissection, occurring most frequently in the internal carotid artery, were observed in seven (1.2%) and six (1%) studies, respectively. No angiography-associated strokes were identified. No association between age, smoking, hypertension, blood pressure, atherosclerosis, or severe vasospasm and angiographic complications was observed. Aneurysm remnants were identified in 36 (5.7%) of the 637 aneurysms that were surgically treated. Atherosclerosis (P < 0.01) or multiple clip applications (P < 0.01) were significantly associated with aneurysm remnants. Angiographic vessel occlusion was observed in 28 (5.7%) patients and resulted in stroke in 14 of these patients. Vessel occlusion was significantly associated with increasing aneurysm size (P < 0.001), atherosclerosis (P < 0.001), temporary clips (P < 0.001), multiple clips (P=0.03), multiple clip applications (P=0.001), and a new postoperative neurological deficit (P=0.002). Severe vasospasm and newly identified aneurysms were observed in 51 and 16 patients, respectively.

CONCLUSION

Angiography after aneurysm surgery is safe and can be routinely performed. Angiography after aneurysm surgery should be particularly considered for patients with large aneurysms or cerebrovascular atherosclerosis and for those who develop new postoperative neurological deficits.

Computerized tomography angiography in isolated third nerve palsies

OBJECT

The goal of this study was to assess the value of computerized tomography (CT) angiography as a diagnostic tool in isolated oculomotor nerve palsies.

METHODS

One hundred consecutive patients who presented with an isolated third nerve palsy were examined by CT angiography. This procedure was followed by conventional cerebral angiography in most patients in whom a vascular abnormality was noted on the CT angiography. Thus, all patients whose symptoms were caused by a compressive aneurysm were identified. The remaining patients were observed clinically to exclude the possibility that a missed cerebral aneurysm caused the isolated third nerve palsy. Eighteen patients harbored a cerebral aneurysm responsible for causing the isolated third nerve palsy. Most of the remaining patients experienced some degree of spontaneous recovery. There was no clinical evidence to indicate that a case of compressive cerebral aneurysm causing the isolated third nerve palsy had been missed on CT angiography.

CONCLUSIONS

Computerized tomography angiography is a reliable diagnostic tool for use in the assessment of patients with an isolated third nerve palsy; it can identify the minority of patients in whom conventional cerebral angiography may be required.

Late blink reflex changes in lesions of thalamus and internal capsule

A 60-year-old man suddenly suffered from left hemiplegia with sensory loss on the left side of his face, trunk, and extremities. Brain CT disclosed hemorrhage in the right thalamus and internal capsule. Blink reflex with electrical stimulation on the left supraorbital nerve showed normal early response (R1) on the left side but absent late response (R2) on both sides, while stimulation of the right supraorbital nerve showed normal R1 on the right side and normal R2 on both sides. This observation suggests that the impulses of R2 from stimulation of the supraorbital nerve on the affected side may be blocked by contralateral lesions of the thalamus and internal capsule.

Treatment for intracranial dural arteriovenous malformations: a meta-analysis from the English language literature

OBJECTIVE

The treatment of intracranial dural arteriovenous malformations (DAVMs) remains problematic. Options include ligature of feeding vessels, endovascular procedures, surgical obliteration, or a combination of the latter two. We conducted a meta-analysis of the English language literature on DAVMs to determine the most effective treatment option related to location and angiographic characteristics.

METHODS

The criteria for inclusion were pre- and post-treatment angiography, a description of the type of treatment, and clinical outcome. The analysis included a total of 258 patients, 248 from a review of 223 published articles and 10 from the authors' series. DAVMs were divided into six categories by location, and the results of treatment were compared based on obliteration rates using chi 2 analysis.

RESULTS

In transverse-sigmoid sinus DAVMs (n = 64), combined therapy (endovascular plus surgical treatment) proved significantly more effective than either therapy alone (P < 0.01). For lesions of the tentorial incisura (n = 66), combined therapy and surgical obliteration alone proved superior to embolization (P < 0.001). For lesions of the cavernous sinus (n = 67), treatment was primarily endovascular, with success rates of 62 to 78% for transarterial and transvenous approaches, respectively. In the anterior fossa (n = 23), surgical obliteration was highly effective, with a success rate of 95%. The small number of cases in both the superior sagittal sinus (n = 28) and middle fossa (n = 10) regions, precluded any statistical analysis. Finally, simple ligature of feeding vessels produced success rates of only 0 to 8% and can no longer be recommended.

CONCLUSION

There is no single ideal treatment for the obliteration of DAVMs. The management of each case is best considered individually. The results of this review serve as a rational starting point for the selection of treatment options.

Orbital colour Doppler imaging in chronic ocular ischaemic syndrome

BACKGROUND

The clinical syndrome of chronic ocular ischaemia may be difficult to diagnose due to its wide range of non-specific presentations, and its diagnosis often implies the presence of underlying severe carotid occlusive disease. Colour Doppler imaging (CDI), a recent advance in ultrasonography that allows for colour-encoded blood flow data of a vascular structure to be displayed simultaneously on a conventional real-time gray-scale B mode image, has been used in the assessment of ocular and orbital vasculature.

METHOD

Four patients with chronic ocular ischaemic syndrome whose diagnoses were aided by CDI are presented.

RESULTS

Orbital CDI was successful in confirming the diagnosis in all four cases. Reversal of blood flow in the ophthalmic arteries was demonstrated. Central retinal vessels were not detected with CDI in all four patients with complete occlusion of the ipsilateral internal carotid artery. One of the four patients had intermittent reversal of ophthalmic arterial flow ipsilateral to the 60% stenosed interna carotid artery.

CONCLUSION

This non-invasive technique is an excellent alternative to invasive vascular studies such as angiography for the diagnosis and evaluation of the chronic ocular ischaemic syndrome.

Ultrasonography for diagnosis and management of carotid artery atherosclerosis. A position paper of the American Society of Neuroimaging

The importance of identifying patients with carotid artery stenosis has attained greater significance in light of recent treatment trials of the efficacy of medical and surgical treatment of both symptomatic and asymptomatic carotid stenosis. Doppler and B-mode ultrasonography can accurately diagnose and quantify stenosis at the cervical carotid artery bifurcation. The development of duplex color-flow instruments has enhanced the sensitivity and specificity of this examination. Ultrasonography should be employed as an initial examination to identify patients with carotid artery stenosis and determine whether further evaluation or treatment is necessary.

Transient ischemic attack and minor ischemic stroke: an algorithm for evaluation and treatment. Mayo Clinic Division of Cerebrovascular Diseases

OBJECTIVE

To report a cost-effective and scientifically based algorithm for the clinical assessment and treatment of patients with transient ischemic attack (TIA) or minor ischemic stroke.

DESIGN

We comprehensively reviewed the literature on the epidemiologic features, assessment approaches, and treatment recommendations for ischemic cerebrovascular disease and developed an algorithm by using the available clinical and research data to support all decision-making steps.

MATERIAL AND METHODS

For patients with TIA or minor ischemic stroke, the appropriate setting for investigation (inpatient or outpatient), suggested diagnostic tests, use of anticoagulants and antiplatelet agents, and indications for surgical treatment are reviewed.

RESULTS

Although stroke is a common cause of death and lost productivity in the United States, the clinical assessment of patients with TIA or minor ischemic stroke has lacked consistency. The simplified algorithm clarifies patients who may be candidates for hospitalization and possible anticoagulation therapy. Initial diagnostic studies should include computed tomography of the head without use of a contrast agent, which quickly distinguishes nonhemorrhagic from hemorrhagic cerebrovascular disease. Evolving noninvasive studies of the cerebral vasculature are providing increasingly sensitive means of detecting stenoses, yet cerebral angiography remains the "gold standard." Treatment options depend on the pathophysiologic findings on diagnostic evaluation.

CONCLUSION

The assessment of patients with ischemic cerebrovascular disease is complex. The simplified algorithmic approach reported herein necessitates entry of appropriate patients into the algorithm. Because of clinical heterogeneity, an algorithm may apply to a wide spectrum of patients but will not cover every situation; hence, evaluation must be guided by a patient's unique history and findings on examination and by the physician's clinical experience.

Complications of cerebral angiography in patients with symptomatic carotid territory ischaemia screened by carotid ultrasound

After nearly 40 years, carotid endarterectomy has been shown to be of benefit to patients with symptomatic carotid territory ischaemia and greater than 70% stenosis of the relevant internal carotid artery. Cerebral angiography is performed before surgery and is not without risk. These risks must be added to those of surgery before recommending the procedure to patients. The study evaluated the local, systemic and neurological complications following digital subtraction angiography with selective catheterisation of the carotid arteries in 200 patients presenting to a cerebrovascular clinic for assessment of cerebral ischaemia. All patients had carotid ultrasound screening before angiography to screen out those with normal arteries or mild disease (less than 30% stenosis of symptomatic internal carotid artery). Complications occurred in 28 patients. There were six (3%) local, two (1%) systemic and 20 (10%) neurological complications. Seventeen neurological complications occurred within 24 hours and there were three late complications (24-72 hours). Neurological complications occurred more frequently when angiography was performed by a trainee rather than a consultant neuroradiologist (p < 0.01). The neurological complications were transient (resolved within 24 hours) in 10/200 (5%), reversible (resolved within seven days) in two (1%) and permanent in 8/200 (4%). Two patients died after a stroke and two other patients suffered a disabling stroke. At 24 hours post angiography the permanent (persisting beyond seven days) neurological complication rate was 2.5%. The incidence of total neurological complications and post angiographic strokes was higher in patients with greater than 90% stenosis of the symptomatic internal carotid artery (p < 0.001). The increased use of non-invasive Doppler duplex screening will reduced the absolute number of patients put at risk of angiography, yet the rate of post angiographic complications is likely to increase as patients with severe stenosis of the symptomatic internal carotid artery are probably most at risk of complications and have most to gain from carotid endarterectomy.

Three dimensional time-of-flight magnetic resonance angiography in carotid artery surgery: a comparison with digital subtraction angiography

Three dimensional time-of-flight magnetic resonance angiography (MRA) and intra-arterial digital subtraction angiography (DSA), considered the gold-standard technique, were compared for pre- and postoperative evaluation of the carotid bifurcation. Images of suitable quality of 194 bifurcations were available with both techniques. Percentage stenosis was graded into 5 groups: A = 0-29%, B = 30-59%, C = 60-89%, D = 90-99%, E = 100% (occlusion). Preoperative MRA (126 bifurcations) overgraded the stenosis in 14 cases and undergraded it in 11. The two techniques agreed in 101 cases and the extent of misgrading was never more than one category. Regression analysis showed a good correlation between the two methods. Severe ulceration was better identified by DSA. As far as the surgical indication was concerned, MRA had a sensitivity of 92.6% and a specificity of 98.3%. In 68 operated cases, postoperative MRA and intraoperative completion angiography showed a satisfactory endarterectomy with no residual stenosis in any of the cases. In conclusion, MRA seems an accurate modality for imaging of carotid bifurcations. Significant limitations still exist for an adequate demonstration of intracranial circulation.

Comparison of magnetic resonance angiography, conventional angiography, and duplex scanning

BACKGROUND AND PURPOSE

To determine the accuracy of magnetic resonance angiography in assessing patients with cerebrovascular disease, we performed a study comparing the results of conventional cerebral angiography, duplex scanning, and magnetic resonance angiography.

METHODS

From 42 patients, a total of 25 carotid arteries were evaluated by all three techniques. The studies were independently read and sorted into five categories according to the degree of stenosis: 0-15%, normal; 16-49%, mild; 50-79%, moderate; 80-99%, severe; and totally occluded.

RESULTS

Magnetic resonance angiography correlated exactly with conventional angiography in 39 arteries (52%); duplex scanning correlated with conventional angiography in 49 cases (65%). Compared with conventional angiography, both magnetic resonance angiography and duplex scanning tended to overread the degree of stenosis. The most critical errors associated with magnetic resonance angiography were three readings of total occlusion in vessels found to be patent on conventional angiograms.

CONCLUSIONS

Although magnetic resonance angiography offers great hope of providing high-quality imaging of the carotid artery with no risk and at less cost, data from this study suggest that misreading the degree of stenosis, or misinterpreting a stenosis for an occlusion, could lead to errors in clinical decisions. Guidelines for use of magnetic resonance angiography in a clinical setting are offered.

Persistent hypoglossal artery: An anomaly leading to false-positive carotid duplex sonography

Duplex ultrasonography is becoming increasingly popular as the sole diagnostic test in the evaluation of carotid artery bifurcation disease. We present a patient with a persistent hypoglossal artery, a rare primitive internal carotid-basilar anastomosis, masquerading as an internal carotid artery stenosis on ultrasound. The operative management of this anomaly is reviewed.

Impact of aging on preoperative evaluation

Approximately 40% of physician office time and 33% of hospital time are devoted to patients 65 years of age or older. Over half of the older population requires some surgical intervention. Because of decreased physiologic reserve and increased number of underlying medical disorders, the older patient is at increased risk for intraoperative and postsurgical complications. Since cardiovascular, pulmonary, and renal complications are frequent in the elderly patient, the preoperative evaluation should emphasize these organ systems. Risk factors should be assessed initially by a focused history and physical examination and by simple tests. Additional diagnostic testing should be reserved for the patient who is not clearly at low or high risk. For optimal preoperative evaluation of the elderly patient, the physician should identify systemic disease, determine if the patient is receiving appropriate therapy, delineate the operative risks, and make recommendations that can potentially reduce the operative risks and postoperative complications.

Carotid surgery without arteriography: noninvasive selection of patients

All carotid noninvasive studies at our institution comprised of duplex scanning, spectral frequency analysis, and ocular-pneumoplethysmography-Gee supraorbital Doppler assessments from 1985-1987 were reviewed. Forty symptomatic and 104 asymptomatic internal carotid arteries, concomitantly studied noninvasively and arteriographically, were identified. All studies were rereviewed prospectively and in blinded fashion. Utilizing peak frequency--internal carotid artery greater than 10 mHz and carotid index (Pf-ICA)/PF-common carotid) greater than 5 as criteria for surgery, 39/40 symptomatic internal carotid arteries were considered appropriate for carotid endarterectomy by noninvasive study. All of these internal carotid arteries had arteriographic confirmation of greater than 50% internal carotid artery stenosis; 22 of them met noninvasive criteria for surgery of peak systolic frequency-internal carotid artery greater than 14 mHz, carotid index greater than 7 and abnormal ocular-pneumoplethysmography-Gee/supraorbital Doppler. All of these had arteriographic confirmation of greater than 80% internal carotid artery stenosis. Eleven asymptomatic internal carotid arteries met spectral frequency criteria for carotid endarterectomy but had normal ocular-pneumoplethysmography-Gee/supraorbital Doppler. Eight in this group had less than 80% stenosis on arteriographic exam. Carotid endarterectomy may be performed without prior arteriography, provided objective criteria are established in a reliable noninvasive lab and met by individual patients.

Perioperative stroke. Part I: General surgery, carotid artery disease, and carotid endarterectomy

Although stroke, defined as a focal neurological deficit lasting more than 24 hr, is uncommon in the perioperative period, its associated mortality and long-term disability are high. No large-scale data are available to identify the importance of recognized risk factors for stroke in the perioperative period. A review of the literature shows that the incidence and mechanism of its occurrence are influenced by the presence of cardiovascular disease and the type of surgery. The most common cause of perioperative stroke is embolism. In non-cardiac surgery, the incidence of perioperative stroke is higher among the elderly. Properly administered, controlled hypotension is associated with minimal risk of stroke. Cerebral vasospasm may be the cause of focal cerebral ischaemia in eclamptic patients, and the aggressive treatment of hypertension may exacerbate the neurological damage. The risk of stroke associated with carotid endarterectomy is closely related to the preoperative neurological presentation, and the experience of the surgical/anaesthetic team. Symptomatic cerebrovascular disease, acute stroke, asymptomatic carotid lesions, preoperative assessment of risk, local and general anaesthesia, cerebral protection and monitoring during carotid endarterectomy are discussed with reference to reducing the risk of perioperative stroke. Adequate monitoring and protection have minimized the risk of ischaemia from carotid clamping, and the major mechanism of stroke is embolization.

Ophthalmologic manifestations of carotid occlusive disease

Amaurosis fugax is perhaps the best known ocular symptom of carotid vascular disease. An understanding of the symptoms and an ability to recognise the characteristic changes of hypotensive retinopathy and the ocular ischaemic syndrome should be familiar to ophthalmologists. In patients with known cerebrovascular disease a careful ophthalmologic examination should be performed to evaluate for the presence of ocular involvement related to emboli and hypoperfusion. Once identified a variety of non-invasive and invasive techniques may be employed to determine the degree of stenosis and an individual treatment plan initiated. Early recognition and treatment of patients with carotid occlusive disease may prevent more serious complications.

Duplex ultrasound assessment of extra cranial carotid artery disease: its introduction into a radiology department

Duplex Doppler ultrasound (DDU) is a non-invasive and potentially accurate modality for assessing carotid bifurcation disease. It is however technically difficult and an appreciable learning curve has been identified. To assess the accuracy of DDU upon introduction into a radiology department with experienced sonographers and radiologists we reviewed the first twenty-five (25) cases in patients, having both DDU and carotid angiography. Sensitivity of 95% and specificity of 81% were obtained for differentiating greater or less than 50% internal carotid artery diameter stenosis, and in detection of 80% or greater stenosis sensitivity and specificity were 83% and 100% respectively. We conclude that DDU is accurate when introduced into a department already competent in ultrasonography, with results being achieved similar to those reported from more experienced centres. Our results also support the appropriateness of the applied criteria for grading of carotid stenosis.

Neurologic complications of axillary and brachial catheter arteriography in atherosclerotic patients: predictive factors

Catheter arteriography by the axillary or brachial route can be responsible for central neurologic complications. The objectives of this prospective study were to define the predictive factors of these complications and determine their incidence. This report is based on 288 consecutive arteriography sessions performed between January 1985 and June 1987. All patients had arterial atheromatous pathology. Ten central neurologic complications (3.5%) occurred, two of which (0.7%) were permanent. Four factors were significantly associated with increased incidence of central neurologic complications: antecedent transient ischemic attack (p less than 0.001); tight (greater than 80%) stenosis of at least one internal carotid artery (p less than 0.02); angina pectoris (p less than 0.05); age over 80 years old (p less than 0.001). Seldinger's or Dos Santos' techniques are preferable to axillary or brachial catheter techniques for investigation of the lower limbs and the abdominal aorta. The former obviates the need to catheterize the aortic arch and reduces the risk of embolism to the supraaortic arteries. Digital venous arteriography is an alternative to aortic arch catheterization when investigating the supraaortic arteries in the presence of risk factors.

Asymmetric proliferative diabetic retinopathy and carotid artery disease

The authors prospectively evaluated 387 consecutive patients with proliferative diabetic retinopathy (PDR) for asymmetry in posterior segment neovascularization and its relationship to carotid artery disease. For the purpose of this study, asymmetry is defined as the presence of PDR with high-risk characteristics (as per the Diabetic Retinopathy Study) in one eye, with neither proliferative nor preproliferative changes in the opposite eye. Over the 2-year time period of the study, 20 (5.2%) of 387 patients manifested asymmetric PDR by this definition. All 20 patients underwent carotid artery noninvasive testing and 4 (20%) were found to have hemodynamically significant carotid artery disease. Two of the four patients had their proliferative retinopathy ipsilateral to their severe carotid artery stenosis. This finding does not support the hypothesis that a hemodynamically significant carotid artery stenosis protects against the development of PDR.

Complications of cerebral angiography for patients with mild carotid territory ischaemia being considered for carotid endarterectomy

It is essential to image the carotid bifurcation adequately in patients with symptomatic carotid territory ischaemia if they are being considered for carotid endarterectomy. Optimal resolution is achieved by selective intraarterial contrast angiography which is an invasive procedure carrying some risk. The overall risk-benefit of carotid endarterectomy is currently being investigated in several large randomised trials in Europe and North America. Because cerebral angiography is a prerequisite for carotid endarterectomy, the risks of cerebral angiography will need to be added to those of surgery when considering whether carotid endarterectomy is effective in the management of these patients. This study evaluated prospectively 382 patients with symptomatically mild carotid ischaemia who had cerebral angiography to visualise a potentially resectable lesion at the carotid bifurcation. Complications followed 14 cerebral angiograms in 13 patients (3.4%); two complications were local (0.5%), two systemic (0.5%) and 10 were neurological (2.6%). The neurological complications were transient (TIA 1, generalised seizure 1) in two patients (0.5%), reversible (stroke) in three (0.8%) and permanent (stroke) in five patients (1.3%). There were no deaths. The significant risk factors for post angiographic stroke were (1) stroke before angiography compared with transient ischaemic attacks of the eye or brain and (2) the presence of greater than or equal to 50% diameter stenosis of the symptomatic internal carotid artery; unfortunately it may be the latter patients who are most at risk of stroke as part of the natural history of their disease and therefore most in need of prophylactic carotid endarterectomy (which requires cerebral angiography). The absolute risk of post-angiographic stroke of patients for cerebral angiography using clinical evaluation and Duplex carotid ultrasound screening.

Role of duplex scanning in the selection of patients for carotid endarterectomy

A retrospective review of 63 patients undergoing duplex scanning and angiography for suspected carotid artery disease was performed to evaluate the need for routine angiography before carotid endarterectomy. A consultant surgeon (M.H.) made a simulated management decision on the basis of a clinical summary and a duplex scan report. Twenty-four patients were selected for surgery without angiography; duplex scanning had a sensitivity of 100 per cent and a specificity of 90 per cent in the detection of internal carotid artery stenosis. In two cases duplex scanning misdiagnosed a total occlusion as a critical stenosis. Eighteen patients failed to meet the criteria for surgery and were referred for angiography. Twenty-one patients were selected for conservative treatment on the basis of the duplex scan report. Combining the surgical and conservative groups (45 patients), duplex scanning had a sensitivity of 96 per cent and specificity of 95 per cent for the detection of stenosis greater than 50 per cent. In the identification of a total occlusion, duplex scanning had a poor sensitivity of 50 per cent. These results suggest that routine angiography before carotid endarterectomy is unnecessary in selected patients but that a suspected occlusion should be confirmed by angiography.

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.

Pupil-sparing oculomotor palsy caused by fusiform arteriosclerotic aneurysm of the basilar artery--a case report

Paresis of the oculomotor nerve is a very rare complication of an unruptured arteriosclerotic fusiform aneurysm of the basilar artery. A handful of cases are described in the world literature. A fifty-four-year-old man with a history of hypertension and diabetes mellitus presented with painless partial oculomotor palsy of sudden onset. A cerebral angiogram demonstrated a tortuous fusiform deformity of the basilar artery and the origin of the posterior cerebral arteries, indicative of an arteriosclerotic aneurysmal dilation. A sudden onset of a pupil-sparing ophthalmoplegia is the typical history of a microvascular infarct of the third nerve, whereas pupillary sparing in aneurysmal oculomotor paresis is a very rare event. Special emphasis has been placed on the pupillary size as a guide for the indication of arteriography. The many exceptions to this rule suggest that cerebral arteriography may be indicated more often than generally believed.

Mapping the cerebral blood vessels with high-field MRI: technical and anatomic review

The technical background and quality of images obtained upon studying the cerebral circulation with high-field MRI are reviewed. Fifty studies were selected as representative of normal cerebral blood vessels to illustrate the anatomic information derived from the review. MRI appears to be a safe, easy, and reliable method of imaging the cerebral circulation noninvasively.

Revision of diagnostic logic using a clinical database

Statistical pattern-recognition techniques have been frequently applied to the problem of medical diagnosis. Sequential Bayesian approaches are appealing because of the possibility of generating the underlying sensitivities, specificities, and prevalence statistics from the estimates of medical experts. The accuracy of these estimates and the consequences of inaccuracies carry implications for the future development of this type of system. In an effort to explore these subjects, the authors used statistics derived from a clinical database to revise the diagnostic logic in a Bayesian system for generating a differential diagnostic list. Substantial changes in estimated a priori probabilities, sensitivities, and specificities were made to correct for significant under- and overestimations of these values by a group of medical experts. The system based on the derived values appears to perform better than the original system. It is concluded that the statistics used in a Bayesian diagnostic system should be derived from a database representative of the patient population for which the system is designed.

Cerebral angiography for cerebrovascular disease: the risks

Cerebral angiography is still suggested as a first line investigation for patients with putative transient ischaemic attacks (TIA) and it is considered by most surgeons as a necessary prelude to carotid endarterectomy. That conventional cerebral angiography involves risk is well known, although the magnitude of this risk is not. Prospective studies of cerebral complications from this technique, published over the last decade, have been analysed to show that the major stroke rate after conventional cerebral angiography for patients with TIAs is likely to be about 2.4 per cent. This must be taken into account if the true morbidity of carotid endarterectomy is to be appreciated (assuming conventional angiograms have been used). Furthermore, since many sufferers are assessed by angiography but not submitted to surgery, a policy of conventional angiography for patients with TIAs puts a far greater number at risk than that actually having carotid endarterectomy.

The limitations of diagnosis of carotid occlusion by Doppler ultrasound

Duplex scanning has been advocated as an acceptable alternative to angiography in the preoperative evaluation of carotid artery stenosis. To evaluate the accuracy of carotid Doppler in differentiating severe carotid stenosis from occlusion, we compared the results of angiography with duplex scanning in 124 carotid arteries (62 patients) and with continuous-wave Doppler in 662 carotid arteries (331 patients). The specificity was 95-99%, sensitivity was 86-96%, and accuracy was 95-98%. Duplex scanning wrongly identified occlusion in four arteries and failed to detect occlusion in one artery. In making decisions prior to carotid endarterectomy, even infrequent errors are unacceptable. We recommend angiography of all surgical candidates with apparent severe stenosis when the internal carotid artery cannot be clearly identified on duplex, or to distinguish apparent occlusion from undetectably low blood flow.

Vertebral artery Doppler sonography

We have examined the vertebral and subclavian arteries in 1,205 patients using directional continuous-wave (c-w) Doppler sonography, and compared the sonographic findings with the results of unilateral or bilateral retrograde brachial arteriographies in the same patients. Doppler sonography revealed 33 false positives among 909 cases with normal angiographic findings. Some types of vertebral artery (VA) lesions allowed an excellent, others a fairly good differentiation by Doppler sonography: the complete subclavian steal syndrome with constant reversal of VA flow was reliably detected (16 cases). In the incomplete steal syndrome (5 cases) sonography was superior to angiography. Two bilateral distal VA occlusions and seven basilar artery occlusions - six in the proximal third and one in the rostral third - were detected sonographically; four basilar occlusions sparing the caudal third and one case exhibiting rete mirabile anastomoses were not identified by Doppler sonography. Our acoustically defined sonographic criteria did not permit an unequivocal assignment to an anatomical variant or a vascular lesion. The sensitivity in the detection of a severe stenosis at the VA origin amounted to 16 out of 31, and to 12 of 25 in cases with a proximal VA occlusion and reconstitution of the distal VA through cervical collaterals. Our results confirm that the conventional hand-held c-w Doppler sonography cannot replace angiography in the evaluation of vertebro-basilar insufficiency. It rather serves as an aid to the decision for or against angiography, and in the follow-up of angiographically proven lesions. However, several therapeutically important lesions are readily diagnosed by sonography.

Clinical events following neuroangiography: a prospective study

Clinical events following cerebral angiography were prospectively evaluated in 1,002 procedures. The ischemic event rate between 0 and 24 hours was 1.3% (0.1% permanent). This incidence was higher (2.5%) in patients investigated for cerebrovascular disease, but the difference was not significant. In addition, 1.8% of the patients suffered ischemia (0.3% permanent) between 24 and 72 hours after angiography. Cerebral ischemic events occurred as a recurrence or worsening of a preexisting phenomenon. twice as often as de novo. All permanent ischemia was a worsening of a preexisting phenomenon. There was a significant increase in the incidence of neurologic events between 0 and 24 hours when the procedure lasted longer than 60 minutes and when there was systolic hypertension. Trends toward higher incidence were noted with the use of increased volume of contrast, with increased serum creatinine, when transient ischemic attacks or stroke were the indications, and when 3 or more catheters were used. The incidence of neurologic events between 24 and 72 hours increased significantly with the increase in the amount of contrast used, with age, and with diabetes. The occurrence of nonneurologic events (mostly hematomas) was significantly increased by multiple factors. This study shows that events can and do occur beyond the usual observation period of 24 hours but confirms the low risk of cerebral angiography when performed judiciously.

Acute effect of angiographic contrast medium on cortical specific gravity after middle cerebral artery occlusion in rats

Early angiography after cerebral arterial occlusion has been cited as potentially detrimental. This investigation evaluates the effect of acute angiographic contrast medium administration on the cortical edema induced by middle cerebral artery (MCA) occlusion. Sixteen rats underwent MCA occlusion, and after 1 hour half the rats underwent ipsilateral internal carotid injection of meglumine diatrizoate, whereas the remainder underwent cervical internal carotid exposure only. Six rats had only sham operations on the MCA and internal carotid, and 4 other rats served as normal controls. Cortical specific gravity was measured to reflect cerebral edema 4 hours after occlusion or sham operation. Specific gravity of the lateral frontal cortex in the hemisphere ipsilateral to occlusion was 1.0396 +/- 0.0011 (mean +/- SEM) when no angiographic contrast medium was administered, significantly less (p less than 0.01) than in rats exposed to contrast medium (specific gravity 1.0442 +/- 0.0005). The latter value was not significantly different from normal. Other cortical areas on the side of the contrast medium injection were also relatively dehydrated compared with normal controls. Early meglumine diatrizoate administration after MCA occlusion results in a decrease in cerebral cortical edema, possible by inducing an osmotic gradient that draws water from the extravascular space.

Complications following transfemoral cerebral angiography for cerebral ischemia. Report of 159 angiograms and correlation with surgical risk

One hundred fifty-nine transfemoral cerebral angiograms for patients with carotid stenosis who subsequently underwent carotid endarterectomy were reviewed. No patient with an asymptomatic carotid bruit developed cerebrovascular complications during angiography. Patients with transient ischemic attacks (TIAs) had a 4.5% incidence of complications. Patients with stroke in evolution had a complication rate of 7.7%. Patients with completed strokes had no angiographic complications. No complication lasted more than 1 hour; all occurred during angiography or immediately afterwards. Stroke in progress has too high a surgical and angiographic risk to warrant study. Transient ischemic attacks have an acceptable morbidity both surgically and angiographically.

Carotid endarterectomy. Who needs it?

Although carotid endarterectomy is one of the most frequently performed operations in this country, recent evidence casts doubt on its advisability, particularly for patients with ocular manifestations of cerebral ischemia. The following evidence is that: the risk of future stroke in untreated patients with amaurosis fugax, retinal plaques, and infarcts is less than 3% per year, far lower than that expected for cerebral (hemispheric) transient ischemic attacks (TIAs); the perioperative risk of stroke and death after endarterectomy may be much higher than previously suspected; and aspirin is a comparatively risk-free and moderately effective alternative to endarterectomy. Because of the questions raised about the risk-to-benefit ratio of endarterectomy, patients with ocular manifestations of cerebral ischemia should be considered for this operation only as part of a proposed randomized collaborative study.

Detection of unruptured familial intracranial aneurysms by intravenous digital subtraction angiography. Screening of two affected families

The authors discuss the detection of intracranial aneurysms (IA) by means of intravenous digital angiography (ivDSA) in (a)symptomatic first degree relatives of families in which two or more individuals have IA. ivDSA is an almost noninvasive and low-risk diagnostic procedure. Screening, by means of ivDSA, of two affected families is described. In family I which includes 7 members with proven IA, ivDSA has been carried out in 36 asymptomatic individuals: in one, a 6 X 15 mm aneurysm was found at the left posterior communicating artery (PCoA). In family II, including one member with a proven IA and another with a subarachnoid hemorrhage, ivDSA has been carried out in 4 members: one aneurysm with a diameter of 6 mm was found at the left PCoA. Conventional cerebral angiography (CCA) confirmed both IA's. Neurosurgical treatment followed. The advantages and disadvantages of ivDSA vs. CCA as elective screening procedure in such cases are discussed. Screening of asymptomatic first degree relatives of cases with familial IA by means of ivDSA is strongly advocated.