Late angiographic follow-up review of surgically treated aneurysms

The merits of endovascular coil surgery for patients with unruptured intracranial aneurysms

OBJECTIVE

The purpose of this study was to report the morbidity, mortality, angiographic results, and merits of elective coiling of unruptured intracranial aneurysms.

METHODS

Ninety-six unruptured aneurysms in 92 patients were electively treated with detachable coils. Eighty-one of these aneurysms were located in the anterior circulation, and 15 were located in the posterior circulation. Thirty-six aneurysms were treated in the presence of previously ruptured aneurysms that had already undergone operation. Nine unruptured aneurysms presented with symptoms of mass effect. The remaining 51 aneurysms were incidentally discovered in patients with other cerebral diseases and in individuals undergoing routine health maintenance. Angiographic and clinical outcomes and procedure-related complications were analyzed.

RESULTS

Eight procedure-related untoward events (8.3%) occurred during surgery or within procedure-related hospitalization, including thromboembolism, sac perforation, and coil migration. Permanent procedural morbidity was 2.2% ; there was no mortality. Complete occlusion was achieved in 73 (76%) aneurysms, neck remnant occlusion in 18 (18.7%) aneurysms, and incomplete occlusion in five (5.2%) aneurysms. Recanalization occurred in 8 (15.4%) of 52 coiled aneurysms that were available for follow-up conventional angiography or magnetic resonance angiography over a mean period of 13.3 months. No ruptures occurred during the follow-up period (12-79 months).

CONCLUSION

Endovascular coil surgery for patients with unruptured intracranial aneurysms is characterized by low procedural mortality and morbidity and has advantages in patients with poor general health, cerebral infarction, posterior circulation aneurysms, aneurysms of the proximal internal cerebral artery, and unruptured aneurysms associated with ruptured aneurysm. For the management of unruptured aneurysms, endovascular coil surgery is considered an attractive alterative option.

Ceramic Aneurysm Clips

Objective:

To design and manufacture an aneurysm clip that incorporates ceramic jaws and a titanium spring, thereby decreasing susceptibility artifact at the aneurysm neck and allowing intra- and/or postoperative magnetic resonance (MR) evaluation.

Methods:

A series of aneurysm clips were developed using ceramic jaws and a titanium spring. A corresponding clip applicator with a novel clip-applicator interface was developed to improve ergonomics and visibility during clip placement or removal. Ceramic clips were imaged at 3.0 T in a kiwi fruit phantom model and compared with MR-compatible Yaşargil aneurysm clips (Aesculap, AG & Co., Tuttlingen, Germany). Ceramic clips were subsequently evaluated in a human cadaveric model at 1.5 T.

Results:

Ceramic clips were developed initially using silicon nitride ceramic and subsequently with yttria-stabilized zirconia ceramic. The ceramic clip jaws showed reduced susceptibility artifact compared with MR-compatible Yaşargil clips. Closing pressure was maintained over the course of 50 cycles of clip opening and closing. Aneurysm clip jaw crossing was not observed. The novel clip applicator and enhanced applicator-clip interface improved visibility during clip application and reduced the potential for torque during clip removal.

Conclusion:

The use of ceramic material limited MR imaging susceptibility artifact and image distortion in the area immediately surrounding the ceramic jaws. As expected, image distortion occurred around the titanium spring and pivot. However, in the unique design of this new aneurysm clip, the spring is located far enough from the distal end of the jaws to provide an undistorted image of the clipped area.

Effectiveness and costs of screening for aneurysms every 5 years after subarachnoid hemorrhage

BACKGROUND

Patients who survive after subarachnoid hemorrhage (SAH) are at risk for a recurrence despite successful treatment of the ruptured aneurysm and may therefore benefit from screening for new aneurysms.

METHODS

We screened 610 patients with SAH with CT angiography 2-18 years after clipping of the aneurysms. Results of screening were used as input for a Markov decision model. We compared the expected number of recurrent hemorrhages, life expectancy, quality-adjusted life-years (QALYs), and costs associated with the strategies "screening every 5 years" and "no screening."

RESULTS

Screening individuals with previous SAH prevented almost half of the recurrences, slightly increased life expectancy (from 21.06 to 21.08 years), but reduced QALYs (from 12.18 to 12.04) and increased costs (from $2,750 to $4,165 per patient). Screening was cost-saving without increasing QALYs in patients with a more than twofold risk above baseline of both aneurysm formation and rupture and it was cost-saving while increasing QALYs if both risks were at least 4.5 times higher. In patients with reduced quality of life because of fear for a recurrence, screening increased QALYs at a maximum cost of $17,422 per QALY.

CONCLUSIONS

In general, screening patients with previous subarachnoid hemorrhage (SAH) cannot be recommended. Screening can save costs and increase quality-adjusted life-years (QALYs) in patients with a relatively high risk of both aneurysm formation and rupture, and increases QALYs at acceptable costs in patients with fear for a recurrence. More data are needed on risk factors for aneurysm formation and rupture in patients with previous SAH and on management of fear for a recurrence to identify patients who can benefit from screening.

Could late rebleeding overturn the superiority of cranial aneurysm coil embolization over clip ligation seen in the International Subarachnoid Aneurysm Trial?

OBJECT

The present purpose is to define the sensitivity of the superiority of coil embolization observed in the International Subarachnoid Aneurysm Trial (ISAT) according to the rate of late rebleeding over a reasonable range, and to find the range of rebleeding rates for which it may be overturned. In the ISAT, coil embolization appears to be safer than clip ligation at 1 year, and clip occlusion has better long-term efficacy at preventing rebleeding. This leaves open the question of which is better in the longer term.

METHODS

The authors calculate the life expectancy of patients following a subarachnoid hemorrhage (SAH) and compare the life expectancy of those who underwent coil embolization with those who underwent clip ligation in the ISAT cohort.

RESULTS

The 1-year poor outcome rate following treatment climbs rapidly with advancing age. A consequence is that the absolute difference between the poor outcome rates after coil embolization and clip occlusion is lower in those < 50 years of age (3.3%) than it is for those > 50 years of age (10.1%). This difference may be enough to give clip application the advantage in the < 40-year-old group despite the small size of the difference in 1-year rebleeding rates thus far observed (0.152%).

CONCLUSIONS

When treating ruptured cerebral aneurysms, the advantage of coil embolization over clip ligation cannot be assumed for patients < 40 years old. In this age range the difference in the safety of the 2 procedures is small, and the better long-term protection from SAH afforded by clip placement may give this treatment an advantage in life expectancy for patients < 40 years of age.

Developments in the management of autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent life- threatening, hereditary disease. ADPKD is more common than sickle cell anemia, cystic fibrosis, muscular dystrophy, hemophilia, Down's syndrome, and Huntington's disease combined. ADPKD is a multisystemic disorder characterized by the progressive development of renal cysts and marked renal enlargement. Structural and functional renal deterioration occurs in ADPKD patients and is the fourth leading cause of end-stage renal disease (ESRD) in adults. Aside from the renal manifestations, extrarenal structural abnormalities, such as liver cysts, cardiovascular abnormalities, and intracranial aneurysms may lead to morbidity and mortality. Recent studies have identified prognostic factors for progressive renal impairment including gender, race, age, proteinuria, hematuria, hypertension and increased left ventricular mass index (LVMI). Early diagnosis and better understanding of the pathophysiology of the disease provides the opportunity to aggressivly treat hypertension with renin-angiotensin-aldosterone system inhibitors and thereby potentially reduce LVMI, prevent cardiovascular morbidity and mortality and slow progression of the renal disease.

Endovascular treatment of ruptured aneurysms and vasospasm

Despite various criticisms, the International Subarachnoid Aneurysm Trial (ISAT) has provided Class I evidence that endovascular therapy (EVT) results in superior 1-year outcomes, compared with surgical repair of ruptured aneurysms equally amenable to both types of treatment. Although the lower occlusion rates and higher rates of recanalization in aneurysms treated with EVT necessitate serial imaging follow-up, these findings do not seem to translate into unacceptably high rates of rebleeding or retreatment morbidity that outweigh the upfront advantage over surgical clipping. EVT also compares favorably to surgery in the treatment of unruptured aneurysms. A randomized, controlled study similar to ISAT is needed for comparing EVT to surgery. EVT appears to have more limitations of durability in large and giant aneurysms, which warrants further research into stent or liquid embolic-assisted treatment because surgical treatment morbidity is also high. Vasospasm is a frequent and potentially devastating complication of aneurysmal subarachnoid hemorrhage. Angioplasty and intra-arterial drug therapy are effective treatments, with an acceptable morbidity and mortality. Angioplasty is more effective and durable and should be considered early in patients with signs of ischemia refractory to maximal medical therapy.

Completion angiography for surgically treated cerebral aneurysms: an economic analysis

OBJECTIVE

To compare cost-effectiveness of different strategies for completion angiography after cerebral aneurysm clipping.

METHODS

A literature search was used to determine the outcome probabilities and costs of various strategies. The pooled results were used in a Markov cost-effectiveness model to compare quality-adjusted life-years and costs of each strategy. Sensitivity (threshold) analyses and Monte Carlo simulation were used to test variation in the model.

RESULTS

Routine (for all cases) intraoperative angiography proved to be slightly more cost-effective than selective (only for cases deemed "high risk") intraoperative angiography, being both less costly and more effective. Routine postoperative angiography was the least cost-effective. However, in centers whose rates of clip-induced arterial compromise are much lower than the averages reported in the literature, selective angiography might be warranted.

CONCLUSION

Routine intraoperative angiography remains the most cost-effective form of completion angiography after aneurysm clipping, at least at our present state of technology.

Nonhelical acquisition CT angiogram after aneurysmal clipping: in vitro testing shows diminished artifact

Imaging of the cerebral vessels with use of CT angiogram (CTA) after placement of aneurysmal clips is often limited by clip artifacts. We used a phantom to demonstrate a visible reduction in metal artifact when using the axial technique, compared with the usual CTA helical acquisition. This approach may have some advantage when used for CTA with 64-section scanners in the specific circumstance of immediate postoperative imaging after placement of cerebral aneurysmal clips.

GUIDELINES FOR THE SURGICAL TREATMENT OF UNRUPTURED INTRACRANIAL ANEURYSMS

THE MANAGEMENT OF unruptured cerebral aneurysms remains one of the most controversial topics in neurosurgery. To this end, we discuss the diagnosis and estimated prevalence of these lesions as well as review the literature regarding the rate of rupture for cerebral aneurysms and risks of operative intervention. Our interpretation of the literature concludes that aneurysms are present in approximately 1% of the adult population, varying between less than 1% in young adults to 4% in the elderly. The yearly risk of subarachnoid hemorrhage for an unruptured intracranial aneurysm is approximately 1% for lesions 7 to 10 mm in diameter. Based on these assumptions, we recommend that 1) with rare exceptions, all symptomatic unruptured aneurysms should be treated; 2) small, incidental aneurysms less than 5 mm in diameter should be managed conservatively in virtually all cases; 3) aneurysms larger than 5 mm in patients younger than 60 years of age should be seriously considered for treatment; 4) large, incidental aneurysms larger than 10 mm should be treated in nearly all patients younger than 70 years of age; and 5) microsurgical clipping rather than endovascular coiling should be the first treatment choice in low-risk cases. Critical to our guidelines is collaboration by a highly experienced cerebrovascular team of microneurosurgeons and endovascular neurosurgeons working at a tertiary medical center with a high case volume and using a decision-making paradigm designed to offer only low-risk treatments. In certain patients for whom both treatment and natural history carry high risks, such as those with giant aneurysms, nonoperative management is typically elected.

Predictors of Rehemorrhage After Treatment of Ruptured Intracranial Aneurysms

Background and Purpose— The primary purpose of intracranial aneurysm treatment is to prevent rupture. Risk factors for rupture after aneurysm treatment have not been clearly established, and the need to completely occlude aneurysms is debated.

Methods— The Cerebral Aneurysm Rerupture After Treatment (CARAT) study is an ambidirectional cohort study of all patients with ruptured intracranial aneurysms treated with coil embolization or surgical clipping at 9 high-volume centers in the United States from 1996 to 1998. All subjects were followed through 2005, and all potential reruptures were adjudicated by a panel of 3 specialists without knowledge of the initial treatment or aneurysm characteristics. Degree of aneurysm occlusion post-treatment was evaluated as a predictor of nonprocedural rerupture in univariate Kaplan–Meier analysis (log-rank test) and in a Cox proportional-hazards model after adjustment for potential confounders and censoring at time of retreatment.

Results— Among 1001 patients during a mean of 4.0 years follow-up, there were 19 postprocedural reruptures; median time to rerupture was 3 days and 58% led to death. The degree of aneurysm occlusion after treatment was strongly associated with risk of rerupture (overall risk: 1.1% for complete occlusion, 2.9% for 91% to 99% occlusion, 5.9% for 70% to 90%, 17.6% for <70%; P <0.0001 in univariate and multivariable analysis). Overall risk of rerupture tended to be greater after coil embolization compared with surgical clipping (3.4% versus 1.3%; P =0.092), but the difference did not persist after adjustment ( P =0.83).

Conclusions— Degree of aneurysm occlusion after the initial treatment is a strong predictor of the risk of subsequent rupture in patients presenting with subarachnoid hemorrhage, which justifies attempts to completely occlude aneurysms.

Optimizing computed tomography to reduce artifacts from titanium aneurysm clips: an in vitro study

Object

At many institutions digital subtraction angiography remains the standard imaging procedure for the postoperative evaluation of patients following placement of a cerebral aneurysm clip largely because of the artifacts produced by the clip on computed tomography (CT). The authors evaluated the effect of various imaging parameters on the quality of 3D reconstructions from CT scans while imaging a phantom to optimize the CT angiograms.

Methods

Using multidetector CT scanners with submillimeter detector collimation (0.625 mm), the authors scanned a silicone phantom with attached commercial aneurysm clips. Slice thickness, reconstruction overlap, kilovolt level, milliampere level, and pitch were varied. Neuroradiologists, who were blinded to the scanning parameters, rated the reconstructions for image quality and artifact reduction.

Results

Images of the titanium clip using 140 kV and 380 mA with 0.625-mm overlapping reconstructed slices provided excellent 3D visualization of both the clip and the aneurysm model, even when using two adjacent clips.

Conclusions

Overlapping reconstructions combined with thin-section acquisition can provide detailed images of titanium clips and surrounding tissues without the use of low-pitch values.

Prototypical metal/polymer hybrid cerebral aneurysm clip: in vitro testing for closing force, slippage, and computed tomography artifact

Object

The aim of this study was to explore the possibility that a hybrid aneurysm clip with polymeric jaws bonded to a metal spring could provide mechanical properties comparable to those of an all-metal clip as well as diminished artifacts on computed tomography (CT) scanning.

Methods

Three clips were created, and Clips 1 and 2 were tested for mechanical properties. Clip 1 consisted of an Elgiloy spring (a cobalt-chromium-nickel alloy) bonded to carbon fiber limbs; Clip 2 consisted of an Elgiloy spring with polymethylmethacrylate (PMMA) jaws; and Clip 3 consisted of PMMA limbs identical to those in Clip 2 but bonded to a titanium spring. Custom testing equipment was set up to measure the aneurysm clip clamping forces and slippage. Clips 2 and 3 were visualized in vivo using a 64-slice CT unit, and the slices were reformatted into 3D images.

Results

According to the testing apparatus, Clip 2 had a similar closing force but less slippage than three similar commercial aneurysm clips. The artifact from the cobalt alloy spring on CT scanning largely offset the advantage of the nonmetal PMMA limbs, which created no artifact. The hybrid titanium/PMMA clip (Clip 3) created very little artifact on CT and allowed visualization of the phantom through the limbs.

Conclusions

It is feasible to build a potentially biocompatible hybrid cerebral aneurysm clip with mechanical properties that closely resemble those of conventional metallic clips. Further testing should be directed toward establishing the reliability and biocompatibility of such a clip and optimizing the contour and surface treatments of the polymer limbs.

Clinical outcome and ischemic complication after treatment of anterior choroidal artery aneurysm: comparison between surgical clipping and endovascular coiling

BACKGROUND AND PURPOSE

Although coiling has been favorably comparable with clipping for treatment of most intracranial aneurysms, there is a controversy on which modality is safer for anterior choroidal artery (AchoA) aneurysm. We retrospectively evaluated the clinical outcomes and treatment-related complications after surgical clipping and endovascular coiling of AchoA aneurysms.

MATERIALS AND METHODS

Seventy-three AchoA aneurysms were recruited from 1895 intracranial aneurysms, which were treated either by surgical clipping or by endovascular coiling in 4 institutions between May 1999 and December 2006. The AchoA aneurysms were dichotomized according to the modality of treatment, the coil group (37 patients; 38 aneurysms) and the clip group (35 patients; 35 aneurysms). Clinical outcomes and incidence of treatment-related complications between 2 groups and the factors influencing the clinical outcomes were evaluated.

RESULTS

There was no rebleeding in both groups during follow-up, for 4-72 months (mean, 27 months) in the coil group and for 3-84 months (mean, 34 months) in the clip group. In the coil group, 31 patients (83.8%) had favorable outcome (modified Rankin Scale score [mRS], 0-3). In the clip group, 31 patients (88.6%) had favorable outcome. The complication of coiling was transient contralateral hemiparesis in 2 patients, who recovered completely. The complications of clipping were permanent contralateral hemiparesis due to AchoA infarction in 4 patients and third-nerve palsy in 1 patient. Hunt and Hess grade 4 or 5 and AchoA infarction were significantly correlated with poor outcome (mRS, < or =4). Clipping had significantly higher incidence of AchoA infarction than coiling (P < .05).

CONCLUSION

Coiling of AchoA aneurysms appears comparable with clipping in clinical outcome and prevention of rebleeding, with significantly lower incidence of AchoA infarction than clipping.

Clip reconstruction and sling wrapping of a fusiform aneurysm: technical note

OBJECTIVE

To describe an alternative method of clip reconstruction and wrapping of fusiform aneurysms that provides structural support for the reconstructed parent artery or residual aneurysm.

CLINICAL PRESENTATION

A 57-year-old woman with an unruptured distal middle cerebral artery fusiform aneurysm underwent surgical treatment via a pterional craniotomy.

TECHNIQUE

A right-angled titanium clip was used to obliterate the aneurysm and to clip reconstruct the parent vessel, which was composed of a single inflow and outflow vessel. After the aneurysm was decompressed with a fine-gauge needle, the remnant/parent artery was wrapped with a thin layer of muslin gauze followed by circumferential application of the Gore-tex (W.L. Gore and Associates, Inc., Flagstaff, AZ) sling. Finally, a second right-angled aneurysm clip was applied to the free ends of the sling immediately adjacent to the parent vessel while the sling was cinched against the parent vessel. This maneuver allowed the Gore-tex material to buttress the reconstructed vessel circumferentially.

CONCLUSION

Clip reconstruction with a Gore-tex sling preserves the parent vessel and simultaneously buttresses the reconstructed vessel wall with radial forces provided by the Gore-tex material. This method is a novel alternative to conventional methods for the treatment of fusiform aneurysms.

Assessment of flow in perforating arteries during intracranial aneurysm surgery using intraoperative near-infrared indocyanine green videoangiography

OBJECTIVE

Perforating arteries are commonly involved during the surgical dissection and clipping of intracranial aneurysms. Occlusion of perforating arteries is responsible for ischemic infarction and poor outcome. The goal of this study is to describe the usefulness of near-infrared indocyanine green videoangiography (ICGA) for the intraoperative assessment of blood flow in perforating arteries that are visible in the surgical field during clipping of intracranial aneurysms. In addition, we analyzed the incidence of perforating vessels involved during the aneurysm surgery and the incidence of ischemic infarct caused by compromised small arteries.

METHODS

Sixty patients with 64 aneurysms were surgically treated and prospectively included in this study. Intraoperative ICGA was performed using a surgical microscope (Carl Zeiss Co., Oberkochen, Germany) with integrated ICGA technology. The presence and involvement of perforating arteries were analyzed in the microsurgical field during surgical dissection and clip application. Assessment of vascular patency after clipping was also investigated. Only those small arteries that were not visible on preoperative digital subtraction angiography were considered for analysis.

RESULTS

The ICGA was able to visualize flow in all patients in whom perforating vessels were found in the microscope field. Among 36 patients whose perforating vessels were visible on ICGA, 11 (30%) presented a close relation between the aneurysm and perforating arteries. In one (9%) of these 11 patients, ICGA showed occlusion of a P1 perforating artery after clip application, which led to immediate correction of the clip confirmed by immediate reestablishment of flow visible with ICGA without clinical consequences. Four patients (6.7%) presented with postoperative perforating artery infarct, three of whom had perforating arteries that were not visible or distant from the aneurysm.

CONCLUSION

The involvement of perforating arteries during clip application for aneurysm occlusion is a usual finding. Intraoperative ICGA may provide visual information with regard to the patency of these small vessels.

Ruptured fusiform aneurysm of the proximal anterior cerebral artery (A1 segment)

A 42-year-old man presented with a ruptured fusiform aneurysm of the proximal anterior cerebral artery (A(1) segment) manifesting as sudden onset of severe headache. Brain computed tomography revealed subarachnoid hemorrhage in the basal cisterns, and left carotid angiography demonstrated a fusiform aneurysm of the left A(1) segment. He underwent surgery via the left pterional approach. The left A(1) segment exhibited a fusiform configuration. Adequate development of the anterior communicating artery was confirmed. Trapping of the aneurysm was performed. The aneurysm was associated with atherosclerotic changes. The postoperative course was uneventful, and the patient was discharged without neurological deficits 1 month after surgery. Fusiform aneurysm of the A(1) segment is quite rare, and tends to bleed, so must be treated. The atherosclerotic origin indicates long-term follow up to identify subsequent lesions.

Use of endovascular coil embolization and surgical clip occlusion for cerebral artery aneurysms

OBJECT

In recent years, endovascular treatment of cerebral artery aneurysms (CAAs) has received greater attention. The authors evaluated patient demographics, endovascular and surgical approaches, and basic outcomes in the treatment of CAAs in a nationally representative administrative database.

METHODS

Using the Nationwide Inpatient Sample from 1998 to 2003, diagnosed CAA coded as either an unruptured or ruptured lesion and treated with surgical clip occlusion, wrapping combined with endovascular repair, or endovascular repair alone was included in the present study.

RESULTS

Treatment of CAAs significantly increased for unruptured (from 4036 to 8334 cases, p = 0.002) but not ruptured (from 9330 to 11,269 cases, p = 0.231) lesions. Endovascular treatment of CAAs in particular also increased in patients with unruptured (from 11 to 43%, p < 0.001) and ruptured (from 5 to 31%, p < 0.001) lesions. In 2003, the mortality rate associated with unruptured CAAs treated using clip occlusion (1.36%) or endovascular repair (1.41%) was similar, whereas rate differences were noted between these treatments for ruptured CAAs (12.7% for clip occlusion compared with 16.6% for endovascular repair; p = 0.05). Endovascular treatment of unruptured CAAs was associated with a shorter length of stay (LOS) and higher rate of discharge to home compared with those for clip occlusion. The LOS was also shorter in patients with endovascularly treated ruptured CAAs. Aneurysm type (odds ratio [OR] 10.1, ruptured lesion), patient age (OR 1.28, each 10 years), comorbid conditions (OR 1.08, each condition), and hospital case volume (OR 0.97, each additional case) were significant predictors of death in the regression model.

CONCLUSIONS

Endovascular techniques for the treatment of CAAs are being used increasingly in the US, although the majority of patients with this pathological entity still undergo surgical clip occlusion. In cases of unruptured CAAs, endovascular treatment is associated with a shorter LOS and higher discharge-to-home rate. Aneurysm status, patient age, comorbid conditions, and hospital case volume are significant predictors of death. Finally, demographic differences exist between the populations presenting with unruptured or ruptured CAAs.

Microsurgical removal of previously placed aneurysm clips and application of new clips for recurrent cerebral aneurysms

✓ A technique is described for removing previously placed aneurysm clips and applying new aneurysm clips for the treatment of regrown or reruptured cerebral aneurysms in patients more than 10 years after the original clipping of the aneurysm neck. The adherent tissue covering previously placed clips is cut just on and alongside the clips themselves using a small scalpel. Using the clip applicator, gentle pressure is applied to open the clip blade as little as possible. The aneurysm clip is carefully slid out along the line where the clip blade has resided, and a new aneurysm clip is applied. The procedure was successfully accomplished in four patients. Whereas three of these patients had an uneventful postoperative course, the remaining patient experienced transient right oculomotor nerve palsy and left-sided motor weakness. The present technique is a useful procedure for treatment of regrown or reruptured cerebral aneurysms occurring a significantly long time after initial clipping of an aneurysm neck.

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.

Noninvasive imaging of treated cerebral aneurysms, Part II: CT angiographic follow-up of surgically clipped aneurysms

Although not useful for the evaluation of coiled aneurysms, CT angiography (CTA) is far superior to MR angiography (MRA) for the evaluation of aneurysms after surgical clipping. Using the latest multidetector row scanners and optimized imaging parameters, CTA can often effectively depict and follow small aneurysm remnants; demonstrate patency, stenosis, or vasospasm in the adjacent parent vessels; and provide surveillance of the entire cerebrovasculature for de novo aneurysms after surgical clipping. Despite these advances, conventional angiography remains the gold standard for the evaluation of surgically treated aneurysms and should be liberally used to resolve any cases of diagnostic uncertainty on noninvasive imaging.

THE STOCKHOLM 20-YEAR FOLLOW-UP OF ANEURYSMAL SUBARACHNOID HEMORRHAGE OUTCOME

OBJECTIVE

To assess the clinical and radiological long-term outcome after aneurysmal subarachnoid hemorrhage (SAH) in a defined referral area regarding recurrent SAH and de novo aneurysm formation.

METHODS

One hundred and two 1-year survivors after aneurysmal SAH, who were treated at the Neurosurgical Clinic, South Hospital, Stockholm, Sweden, between 1983 and 1985, were followed for 20 years. Forty-nine surviving patients were reevaluated. Hospital records and death certificates were scrutinized for all 53 nonsurviving patients. Clinical history penetration, Mini Mental Status, Rankin Disability Score, and Barthel Index were used to evaluate the outcome. Computed tomographic angiography was used to investigate the cerebral arteries.

RESULTS

One hundred and two patients were traced. Fifty-three patients were deceased. One patient had a hospital record of sustaining an aneurysmal SAH from a known but not clipped aneurysm. Three patients had nonaneurysmal intracerebral hemorrhage and two sustained traumatic SAH. There were 49 surviving patients. Six refused follow-up. None of these patients had hospital records of intracranial disease. Three of the 43 remaining patients could not be tested. None of the survivors had experienced a new SAH. Aneurysm base remnants were observed in 1% (eight patients, 790 person-years of follow-up) and de novo aneurysms were observed in 0.9% (seven patients, 790 person-years of follow-up).

CONCLUSION

From this epidemiological survey of patients with aneurysmal SAH, it was found that none of the patients experienced a recurrent subarachnoid bleed from the treated aneurysm during a 20-year follow-up period. Thus, a routine extreme long-term follow-up period is not necessary. De novo aneurysm formation and possible enlargements of aneurysm base remnants were observed in almost 2% of patients per person year and should, therefore, be subject of a routine, long-term follow-up.

ENDOVASCULAR COIL EMBOLIZATION OF RUPTURED AND UNRUPTURED POSTERIOR CIRCULATION ANEURYSMS

OBJECTIVE

Treatment of posterior circulation aneurysms poses a great technical challenge for the practicing neurosurgeon. The advent of endovascular techniques has made such treatment more feasible. We report our experience with the endovascular management of ruptured and unruptured posterior circulation aneurysms during the past 10 years.

METHODS

A retrospective analysis was performed on all patients with posterior circulation aneurysms undergoing endovascular treatment at Jefferson Hospital for Neuroscience between July 1995 and December 2005. This yielded 275 patients (67 men and 208 women). The degree of aneurysm occlusion was determined by the operating endovascular neurosurgeon at the time of the procedure. Successful embolization was defined as greater than 95% occlusion of the dome without any coil prolapsing into the parent vessel. Clinical outcome was evaluated using the modified Glasgow Outcome Scale. Clinical follow-up data was obtained for 262 patients (95.3%); the follow-up period ranged from 1 to 94 months (mean, 31.8 mo for procedures performed before 2004 and 13.3 mo for procedures performed during 2004 and 2005). Angiographic follow-up data was obtained for 224 patients (84.8%) for periods ranging from 6 to 94 months (mean, 31.3 mo for procedures performed before 2004 and 13.7 mo for procedures performed during 2004 and 2005).

RESULTS

Based on the Hunt and Hess grading scale, the patient population included 106 patients (38.5%) with unruptured aneurysms, 43 patients (15.6%) with Grade I aneurysms, 16 patients (5.8%) with Grade II aneurysms, 56 patients (20.5%) with Grade III aneurysms, and 54 patients (19.6%) with Grade IV aneurysms. The locations of the posterior circulation aneurysms included 189 (68.7%) in the basilar apex or posterior cerebral artery, 23 (8.4%) in the basilar trunk/anterior inferior cerebellar artery, 22 (8%) in the superior cerebellar artery, and 41 (14.9%) in the vertebral artery or posterior inferior cerebellar artery. Of the 275 patients, 208 (76%) were women and 67 (24%) were men. The mean age at the time of treatment was 53.9 years (range, 7–90 yr). Of all patients treated, 237 patients (87.8%) had successful embolization (&gt;95% occlusion of the dome). On angiographic follow-up, 55 patients (24.5%) developed recanalization of at least 5%. Retreatment was required in 11 patients (4.9%; 0.01%/patient yr) and rehemorrhage occurred in three patients (1.1%; 0.003%/patient yr). Clinical follow-up was graded using the modified Glasgow Outcome Scale (mGOS) and revealed 229 patients (87.4%) in the mGOS I category, 12 patients (4.6%) in the mGOS II category, eight patients (3%) in the mGOS III category, two patients (0.8%) in the mGOS IV category, and 11 patients (4.2%) were deceased (mGOS V). Clinically significant vasospasm requiring angioplasty occurred in 11 patients (6.5%) with subarachnoid hemorrhage, and 120 patients (71%) with subarachnoid hemorrhage required ventricular shunts. Complications causing clinical morbidity occurred in 14 patients (5.1%) and ranged from postoperative ischemia to recurrent subarachnoid hemorrhage. Of all clinical factors evaluated, Hunt and Hess grade was the strongest predictor of good clinical outcome (P &lt; 0.0001).

CONCLUSION

Endovascular coil embolization of posterior circulation aneurysms is an effective treatment in the short term but is associated with recurrence, which requires close surveillance, possible retreatment, and can, albeit very rarely, lead to rehemorrhage. Future technological advancements such as the development of biologically active coils will be essential in the permanent obliteration of aneurysms.

Retreatment of ruptured cerebral aneurysms in patients randomized by coiling or clipping in the International Subarachnoid Aneurysm Trial (ISAT)

BACKGROUND AND PURPOSE

Because the long-term security of endovascular treatments remains uncertain, a follow-up study of the patients treated in the International Subarachnoid Aneurysm Trial was performed to compare the frequency, timing, and consequences of aneurysm recurrence.

METHODS

Patient data were reclassified by actual treatment performed. Aneurysm and patient characteristics, including occlusion grades, time and type of retreatment, and clinical outcomes, were compared. The relationship between these variables and late retreatment as a surrogate for recurrence was analyzed by means of the Cox proportional hazards model.

RESULTS

Retreatment was performed in 191 of 1096 (17.4%) patients after primary endovascular coiling (EVT) and in 39 of 1012 patients (3.8%) after neurosurgical clipping. After EVT, 97 (8.8%) patients were retreated early and 94 (9.0%) late, 7 (0.6%) after rebleeding and 87 (8.3%) without. The mean time to late retreatment was 20.7 months. After neurosurgical clipping, 30 (2.9%) patients were retreated early and 9 (0.85%) late, 3 (0.3%) after rebleeding and 6 (0.6%) without. The mean time to late retreatment was 5.7 months. The hazard ratio (HR) for retreatment after EVT was 6.9 (95% CI=3.4 to 14.1) after adjustment for age (P=0.001, HR=0.97, 95% CI=0.95 to 0.98), lumen size (P=0.006, HR=1.1, 95% CI=1.03 to 1.18), and incomplete occlusion (P<0.001, HR=7.6, 95% CI=3.3 to 17.5).

CONCLUSIONS

Late retreatment was 6.9 times more likely after EVT. Younger age, larger lumen size, and incomplete occlusion were risk factors for late retreatment after EVT. After neurosurgical clipping, retreatments were earlier; whereas EVT retreatments continued to be performed throughout the follow-up period. Short-term follow-up imaging is therefore insufficient to detect recurrences after EVT.

A clinical analysis of twelve cases of ruptured cerebral de novo aneurysms

Formation of cerebral de novo aneurysms (CDNA) is rare, and the pathogenesis remains obscure. In this study, we investigated the factors that contribute to the formation of CDNA and suggest guidelines for following patients treated for cerebral aneurysms. We retrospectively reviewed 2,887 patients treated for intracranial aneurysm at our institute from January of 1976 to December of 2005. Of those patients, 12 were readmitted due to recurrent rupture of CDNA, which was demonstrated by cerebral angiography. We assessed clinical characteristics, such as gender, size and site of rupture, past history, and the time to CDNA rupture. Of the 12 patients, 11 were female and 1 was male, with a mean age at rupture of the first aneurysm of 44.7 years (range: 30-69 years). The mean time between the first episode of subarachnoid hemorrhage (SAH) and the second was 8.9 years (range: 1.0-16.7 years). The most common site of ruptured CDNA was the internal carotid artery (5 patients, 41.7%), followed by basilar artery bifurcation (3 patients, 25.0%). In the remaining 4 patients, rupture occurred in the anterior communicating, middle cerebral, anterior cerebral (A1), or posterior cerebral (P1) arteries. In 5 cases (41.7%), the CDNA occurred contralateral to the initial aneurysm. Eleven patients (91.7%) had a past history of arterial hypertension. There was no history of habitual smoking or alcohol abuse in any of the patients. Eight patients underwent clipping for CDNA and three patients were treated with coiling. One patient who had multiple aneurysms was treated with clipping following intra-aneurysmal coiling. Assessment according to the Glasgow Outcome Scale (GOS) of the patients after the treatment was good in 10 cases (83.3%) and fair in 2 cases (16.7%). Although formation of CDNA after successful treatment of initial aneurysm is rare, several factors may contribute to recurrence. In our study, female patients with a history of arterial hypertension were at higher risk for ruptured CDNA. We recommend follow-up imaging studies every five years after treatment of the initial aneurysm, especially in women and those with a history of arterial hypertension.

Traitement de l'hémorragie méningée anévrismale

The incidence of subarachnoid hemorrhages is about 10.5/100,000 persons/year. Early obliteration of the aneurysmal sac is necessary to avoid rebleeding. The neurovascular staff meeting must decide the appropriate obliteration procedure for each patient. Intraoperative morbidity is 8% after endovascular coiling and 10% after microsurgical clipping. Endovascular coiling leads to complete obliteration of the aneurysm in 60% of patients and microsurgical clipping in 95%. Delayed ischemic deficits may be prevented by volemic expansion and calcium channel blockers. Hospitalization and general prophylaxis against deep venous thrombosis, pain and seizures are essential. Curative treatment is required against common complications such as intraparenchymatous hematoma, hydrocephalus, and delayed ischemic deficit.

Neurosurgical management of inadequately embolized intracranial aneurysms: a series of 17 consecutive cases

OBJECTIVE

Inadequately embolized aneurysms (IEA) are coiled aneurysms with a significant remnant (>5%), initially or after recanalisation, or with a coil extrusion deemed too thrombogenic or threatening the blood flow in the parent vessel. Our objective is to report our experience with the surgical clipping (SC) of a consecutive series of 17 IEA considered as not appropriate for an additional endovascular procedure.

METHODS

Between February 1996 and April 2006, we evaluated 523 ICA in 380 patients of whom 192 underwent coil embolisation (CE), 117 with complete occlusion (61%), 47 with near complete occlusion (> or = 95%), 9 with partial occlusion (<95%), and 19 without any coil delivery (attempted embolisation). Of the 173 ICA embolized one or two times, at their radiological follow-up 15 (8.6%) were considered as IEA and not appropriate for an additional CE. Two IEA treated endovascularly before February 1996 were added to this series. The female/male ratio was 0.47 with an average age of 54 years (range, 37-65). All cases were located on the anterior circulation except the last one. The 17 IEA were treated by SC either because of an aneurysm remnant deemed not accessible to a further CE and large enough for direct clipping or because the risks of a thromboembolic event related to extruded coils was too high.

RESULTS

SC was complete in all 17 cases, confirmed angiographically. Postoperatively, the clinical status of two patients deteriorated slightly but transiently. Our surgical experience with this series led us to classify IEA into five types, in three groups: group A (with one type: type A) was the most important group (n = 11) with IEA characterized by an aneurysm residue allowing direct SC, as assessed preoperatively; group B (n = 4) comprised aneurysms with a residue smaller than predicted and showing parent vessel stenosis when a clip was applied to the neck residue requiring the fundus full of coils to be removed followed by either clip application to the neck residue (type B1, n = 3) or suture if the remnant was too small (type B2, n = 1); and group C (n = 2) grouping cases requiring coil extraction through the parent vessel (type C2, n = 1) or through the fundus (type C2, n = 1).

CONCLUSIONS

With this series of IEA, we observed that open surgery of type A and C aneurysms can be a straightforward procedure. Our experience with type B IEA encourages us to wait for a sufficient aneurysm residue before performing SC because of the potential difficulties that may be encountered by the surgeon, particularly in type B2. SC of IEA was very effective with complete occlusion and no permanent morbidity in all 17 cases.

Multislice computed tomography angiography screening for new aneurysms in patients with previously clip-treated intracranial aneurysms: Feasibility, positive predictive value, and interobserver agreement

OBJECT

Multislice computed tomography (CT) angiography may be useful for screening patients with intracranial aneurysms that are treated with clip occlusion. However, cobalt clips produce much more artifact on CT scans than titanium clips, which may hamper the evaluation of the image obtained at the clip site.

METHODS

The authors screened 415 patients with previously ruptured aneurysms that had been treated using cobalt clips. Screening was performed using multislice CT angiography. The feasibility of this modality for screening these patients (based on the complication risk, CT angiography quality, and artifact avoidance) and interobserver agreement were evaluated. Patients in whom the presence of an aneurysm was suspected based on results of CT angiography studies underwent digital subtraction (DS) angiography. False-negative and false-positive findings were recorded, and the positive predictive value (PPV) was calculated. Eight patients (1.9%) had allergies to the contrast material. The quality of the CT angiography image was suboptimal in 14%. In 52%, clip artifacts hampered evaluation of the clip site. In 65 patients who underwent DS angiography, there were nine false-positive and eight false-negative reports related to aneurysms that were either small, located at the clip site, or were infundibula. The PPV on a per-patient basis was 86% (95% confidence interval [CI] 75-94%); for aneurysms at the clip site it was 83% (95% CI 61-95%); and for aneurysms at different locations it was 91% (95% CI 81-97%). The interobserver agreement was good (kappa = 0.69; 95% CI 0.60-0.78).

CONCLUSIONS

Except for the evaluation of images from the clip site, CT angiography has good feasibility with good PPV and interobserver agreement. Drawbacks are that very small aneurysms can be missed and that visualization is poor at the clip site in patients in whom cobalt clips have been placed for occlusion. This second problem can be expected to resolve with the increasing use of titanium clips.

Long-term histological and scanning electron microscopy results of endovascular and operative treatments of experimentally induced aneurysms in the rabbit

OBJECTIVE

Treatment strategies of cerebral aneurysms include surgical clipping and endovascular therapies. To determine the long-term results of these therapeutic strategies, the vessel wall reaction close to the former aneurysm was studied according to the assumption that an intact endothelial layer over the former aneurysm neck constitutes complete vessel wall reconstruction and stable aneurysm obliteration.

METHODS

Aneurysms were created in 40 rabbits by intraluminal elastase incubation of the common carotid artery. Five animals each were assigned to the following groups: untreated, porous stents, polyurethane covered stentgrafts, porous stents with subsequent coiling. Ten animals were treated with coils alone, 10 with clips. After 6 months, angiography, histology, and scanning electron microscopy was performed.

RESULTS

Porous stents did not obliterate the aneurysm, whereas stentgrafts did; in-stent stenosis of up to 60% was present because of neointimal multilayer proliferation. After coiling, the aneurysm dome was occluded with fibrinous and collagenous material, whereas the aneurysm neck was not covered by an endothelial lining. Coil loops lay bare within the vessel, with fresh thrombus material on their surface. After clipping, a thin layer of endothelial lining bridging the two attached vessel walls was present, thereby completely obliterating the aneurysm and reconstructing the vessel wall.

CONCLUSION

This study demonstrates complete and stable aneurysm obliteration with vessel wall reconstruction after clipping, a sufficient obliteration of the aneurysm dome using endovascular techniques, but a failed healing response of the aneurysm neck that might correlate to its associated higher risk of rebleed. Whether or not this is counterbalanced by the better immediate outcome after endovascular treatment remains a matter of debate.

Preventive neurosurgery: population-wide check-up examinations and correction of asymptomatic pathologies of the nervous system

BACKGROUND

Prevention in healthcare is attracting more and more attention. Early identification and correction of anomalies harbouring the risk of a catastrophic event such as aneurysms is the principal rationale for brain check-up programmes. The other aim of preventive screening is to identify progressive lesions with little reversibility such as gliomas. The purpose of the current analysis is to review the frequency of the various incidental findings, the inherent risk and the therapeutic options. RATIONALE FOR CHECK-UP IMAGING AND PREVENTIVE TREATMENT: The average prevalence of asymptomatic intracranial benign tumours, aneurysms and carotid stenoses must be estimated as approximately 1% each. Meningiomas, aneurysms and carotid stenosis become more frequent with increasing age. Mainly vascular anomalies harbour a risk of a catastrophic event, i.e. carotid stenosis and intracranial aneurysms. Only gliomas potentially lose reversibility with time passing. The case of glioma appears to be lost since asymptomatic gliomas are extremely rarely identified on screening examinations, and on the other hand current treatment series do not support that infiltrating gliomas can be cured if only treated early enough. Treatment of the benign tumours, hydrocephalus and arachnoid cysts in the asymptomatic stage does not appear to provide any benefit. RATIONALE FOR GENETIC SCREENING: A number of intracranial tumours, vascular anomalies and degenerative changes are genetically determined. Examples are neurofibromatosis, tuberous sclerosis, von Hippel-Lindau disease and Rendu-Osler's disease. Although familial clustering of aneurysms is well known, the exact genetic anomaly is unknown and probably several genes play a role. Because of the variable penetrance of the inherited disorders with known genetic alterations, screening of affected families is recommended. The conditions are too rare to justify screening of the entire population. Apolipoprotein E genotype is the only accepted predictor of dementia. Routine screening APOE may be considered today, but is highly problematic due to the lack of clear consequences and the potentially negative psychological impact.

COSTS

Implementation of population-wide screening programmes and preventive measures would lead to a substantial additional financial burden. Brain-check-up programmes cannot be considered in isolation. Cardiovascular and oncological programmes would also have to be included from that point of view.

CONCLUSIONS

Population-wide screening with regard to intracranial aneurysms or carotid stenosis with non-invasive imaging techniques and preventive surgery/endovascular therapy can be justified, provided that treatment-associated morbidity is very low. There is no evidence for the rationale of screening for asymptomatic intracranial tumours, cysts or hydrocephalus. Genetic screening cannot be generally recommended, except among families affected by inherited conditions.

Long-term clinical and angiographic follow-up of unclippable wrapped intracranial aneurysms

OBJECTIVE

This is the largest contemporary series examining long-term clinical and angiographic follow-up of unclippable wrapped intracranial aneurysms.

METHODS

The presentation, location and shape of aneurysm, wrapping technique, outcome at discharge and last follow-up, and change in aneurysm at last angiographic follow-up were reviewed retrospectively in 74 patients with wrapped or clip-wrapped aneurysms. Patients in whom wrapping was used in conjunction with primary clipping were excluded.

RESULTS

Of the 74 patients, 11 were lost to follow-up. The mean age of the remaining 63 patients (16 males, 47 females) was 56.5 years (range, 13-89 yr). Fifty-one aneurysms were located in the anterior circulation, and 17 were located in the posterior circulation. Fourteen patients presented with a ruptured aneurysm. Seventeen aneurysms were fusiform. Seven aneurysms were clip-wrapped, and 61 were wrapped with cotton. At discharge the Glasgow Outcome Scale (GOS) score was 5 in 54 patients and 4 in 5 patients. Two patients died from their presenting hemorrhage, and one from a medical comorbidity. The mean clinical follow-up was 44.1 months (range, 1-120 mo). One patient under clinical follow-up experienced subarachnoid hemorrhage. The mean angiographic follow-up of 34 patients was 41.8 months (range, 3-120 mo). During this follow-up period, no patient's aneurysm changed in size or configuration.

CONCLUSION

Wrapping or clip-wrapping of unclippable intracranial aneurysms is safe and seems to confer protection against aneurysmal growth or subarachnoid hemorrhage.

Is routine intraoperative angiography in the surgical treatment of cerebral aneurysms justified? A consecutive series of 147 aneurysms

OBJECTIVE

The role of intraoperative angiography (IA) in the surgical treatment of cerebral aneurysms has remained extremely controversial. We determine the frequency and predictors of unanticipated findings necessitating clip adjustment established on postoperative angiography (PA) in a consecutive series of 147 aneurysms. On the basis of published series, we discuss the utility, safety, accuracy, and cost effectiveness of adjunct IA in the surgical treatment of cerebral aneurysms.

METHODS

We retrospectively examined the charts of 124 consecutive patients harboring 147 aneurysms that were surgically clipped between December 2000 and March 2005 and had PA available for review. Patient demographics, aneurysm size, location, Hunt and Hess score, Fisher grade, mode of aneurysm discovery, time between discovery and surgery, and PA results, as determined by a blinded independent neuroradiologist, were recorded.

RESULTS

PA demonstrated two (1.4%) unexpected residuals, four anticipated residuals (2.7%), and four (2.7%) vessel compromises. Of the six unanticipated outcomes, two of two (100%) unexpected residuals and three of four (75%) vessel compromises were from large aneurysms (P = 0.0001 each). Middle cerebral artery aneurysms comprised 5 of 10 (50%) imperfect outcomes (three expected remnants and two vessel occlusions), which trended toward significance (P = 0.06).

CONCLUSION

IA is recommended during the surgical clipping of complex or large aneurysms and some middle cerebral artery aneurysms. High cost-benefit ratio, false-negative rate, and moderate risk, however, preclude routine use. With future technological advances, IA may warrant broader use by replacing postoperative studies in the neurosurgical management of intracranial aneurysms.

Follow-up of Treated Aneurysms: the Challenge of Recurrences and Potential Solutions

Angiographic recurrences after endovascular treatment of aneurysms with platinum coils are frequent, but hemorrhages are unusual. Recurrences are more frequent in patients with large wide-necked aneurysms, when the initial occlusion is incomplete, and when patients are treated after subarachnoid hemorrhage. Although many occur early on, they can appear years after treatment. None of the recent devices has been proven effective in improving long-term results. A rigorous scientific approach, including randomized trials, is imperative to forward progress in this field.

Current Indications for Aneurysm Surgery

Treatment of cerebral aneurysm has changed greatly over the last several years. Although surgery was the treatment of choice for decades, coiling is coming into more prevalent use now. This article highlights when each modality should be used.

Postoperative three-dimensional CT angiography after cerebral aneurysm clipping with titanium clips: detection with single detector CT. Comparison with intra-arterial digital subtraction angiography

AIM

To assess the significance of three-dimensional computed tomography angiography (3D-CTA) in detecting remnant necks after cerebral aneurysm clipping.

MATERIALS AND METHODS

A total of 59 patients (77 aneurysms) underwent surgery using titanium clips. Two blinded observers independently evaluated the presence of neck remnants on shaded-surface display (SSD) imaging, volume rendered (VR) imaging, and intra-arterial digital subtraction angiography (IADSA).

RESULTS

Mean sensitivity and specificity for detecting neck remnants were 50.0 and 74.2% for SSD imaging, 61.5 and 82.8% for VR imaging, and 92.3 and 92.2% for IADSA, respectively. Receiver operating characteristic (ROC) analysis revealed excellent diagnostic performance for IADSA [mean area under ROC curve (Az)=0.97], and good diagnostic performance for 3D-CTA (Az=0.70 and 0.76 for SSD and VR, respectively). Specificity of VR was better than that SSD (p=0.082), however, there was no significant difference between them.

CONCLUSION

Use of 3D-CTA techniques can facilitate postoperative evaluation.

Outcome of Oculomotor Nerve Palsy from Posterior Communicating Artery Aneurysms: Comparison of Clipping and Coiling

OBJECTIVE:

Recovery of posterior communicating artery aneurysm-induced oculomotor nerve palsy (ONP) after aneurysm coiling has been reported. However, the coil mass may compromise recovery of the nerve. Therefore, we compared the outcome of coiling and clipping for this indication.

METHODS:

We retrospectively compared the outcomes of ONP in 13 patients, six of whom underwent endovascular coiling and seven of whom underwent surgical clipping.

RESULTS:

Six of the seven surgical patients with ONP recovered completely, compared with two of the six patients in the endovascular group. Of the patients with more than 1 year of follow-up, all six surgical patients recovered completely, compared with two of four endovascular patients (P = 0.05). In addition, preoperative complete or partial ONP also was associated with degree of resolution by survival analysis (P = 0.03). All patients with partial ONP in the surgical group and two of three patients in the endovascular group recovered without residual deficits, whereas three of the four patients with complete ONP in the clipping group and none in the coiling group recovered completely. Regardless of the treatment method, time to complete resolution of ONP was 6 months in both groups.

CONCLUSION:

Clipping posterior communicating artery aneurysms was associated with a higher probability of complete recovery from ONP than coiling. Degree of preoperative ONP also affected recovery. If patients can tolerate surgery, it should be considered the treatment of choice.

Psychosocial impact of finding small aneurysms that are left untreated in patients previously operated on for ruptured aneurysms

OBJECTIVES

In patients with previous subarachnoid haemorrhage (SAH) undergoing follow up screening, the authors assessed the impact of finding but not treating very small aneurysms by comparing quality of life (QOL), anxiety, and depression between patients with a newly detected aneurysm that was left untreated (cases) and patients with a negative screening (controls) as this should be incorporated in the evaluation of effectiveness of screening.

METHODS

In patients with previous SAH undergoing screening for new aneurysms the authors compared QOL (SF-36, EURO-QOL, and a screening related questionnaire), anxiety, and depression (Hospital Anxiety and Depression Scale (HADS)) between cases and controls. Differences in scores on the SF-36, EURO-QOL, and HADS were assessed with Student's t test and differences in proportions of patients with HADS scores in the pathological range and screening related changes with chi2 analysis. The authors powered the study to detect a moderate, clinically relevant difference.

RESULTS

Thirty five cases and 34 controls were included. Trends for health related QOL, anxiety, depression, and consequences in daily life pointed in the same direction of a less favourable situation for cases but all effects were small, and did not reach statistical significance. On the screenings specific questionnaire, cases more often (but not statistically significant) reported changes in daily life.

CONCLUSIONS

The authors found no major or moderate impact on QOL, anxiety, and depression of the awareness of having an untreated aneurysm, which was detected at screening, although most items showed a trend towards more negative effects for cases. Minor effects on individual level cannot be excluded by this study.

Endovascular management of unruptured intracranial aneurysms

Endovascular coil embolisation is increasingly used to treat unruptured intracranial aneurysms (UIA). Endovascular coil embolisation of UIA is associated with a 5-10% risk of morbidity and nearly zero mortality from the procedure. Complete or near complete occlusion is usually achieved in >90% of cases, and endovascular therapy seems to reduce the risk of future rupture significantly. Specific selection criteria for endovascular embolisation and novel approaches to endovascular treatment of aneurysms are discussed. Endovascular therapy appears to be a safe and effective treatment for selected UIA. Treatment failure rates will probably decrease with greater experience and advances in techniques and devices. Further study with long term follow up, however, is still necessary to characterise the efficacy, durability, and cost efficiency of endovascular treatment of UIA.

Direct Costs of Surgical Clipping and Endovascular Coiling of Unruptured Intracranial Aneurysms

BACKGROUND

Unruptured intracranial aneurysms can be preventively treated by surgical clipping or endovascular coiling. We determined in detail the costs of these treatments.

METHODS

We included patients who were treated for an unruptured aneurysm between 1997 and 2003. Patients coiled in this period were matched with clipped patients according to the year of treatment, age and gender. Considering clipping and coiling, we compared all pre-admission costs of diagnostic procedures, all costs of treatment, and costs during follow-up including standard angiographic control examinations at 6 and 18 months after coiling. Costs were calculated as the product of the used resources and the costs of these resources.

RESULTS

The mean price for clipping was EUR 8,865.42 and that for coiling EUR 10,370.29. The difference was mainly determined by the higher material costs of coiling (EUR 5,300) compared with clipping (EUR 690). Costs of clipping were mainly determined by the need for intensive care facilities (1.2 days after clipping and 0 days after coiling) and the length of hospital stay (10.5 days after clipping and 3.4 days after coiling). After bootstrapping the data, costs of coiling were on average EUR 1,553 (95% confidence interval: EUR 1,539-1,569) higher than those of clipping.

CONCLUSIONS

For unruptured intracranial aneurysms, direct in-hospital costs of coiling are on average higher than those of clipping, mostly because of the more expensive coils.

Recurrent or new symptomatic cerebral aneurysm after previous treatment

SUMMARY

With the establishment of endovascular coiling as a successful treatment for symptomatic cerebral aneurysms, attention is now being directed at the durability of this treatment. If this is to be accurately done it will be important to understand the causes of symptomatic aneurysm presentation after previous treatment. In order to assess this we undertook a retrospective review, covering the four year period from 2000 to 2004, of all patients re-presenting with a symptomatic saccular aneurysm after previous treatment. Seven patients were identified, six presenting with subarachnoid haemorrhage (SAH) and one with a third cranial nerve palsy. Three patients had incomplete clipping of their aneurysms and all presented within months of their initial treatment. The other four patients presented between five and 20 years after primary treatment and all were felt to have new cerebral aneurysms. Two of these patients had aneurysms develop at the same location as their previously treated lesions, however these were still felt to be new aneurysms rather than re-growth or recurrence because of their morphology. Based on our findings it would appear that development of a new cerebral aneurysm after clipping is more of a risk than aneurysm recurrence from treatment failure. This will need to be considered when evaluating re-presentation after treatment by either coiling or clipping and more importantly, perhaps we should be directing more attention to preventing disease progression rather than treatment failure.

Midterm prevention of rebleeding by Guglielmi detachable coils in ruptured intracranial aneurysms less than 10mm

The midterm effects of coil embolization for ruptured aneurysm remain unknown. We investigated the prevention of rebleeding by GDC in ruptured aneurysms. Between March 1998 and April 2003, we treated 38 ruptured aneurysms measuring less than 10 mm in diameter. The patients were followed for a median of 37.3 months. During the follow-up term, aneurysms treated by coil embolization did not develop rebleeding after 1 month. We conclude that an embolized aneurysm measuring 10 mm or less remains quite stable over 3 years.

Outcome of Surgical Clipping of Unruptured Aneurysms as it Compares with a 10-Year Nonclipping Survival Period

OBJECTIVE

Recent studies on the natural history of unruptured intracranial aneurysms dictate that we reevaluate the risks and benefits of surgical intervention as it compares with the natural course. We analyzed the outcome of surgical clipping of a patient cohort with unruptured aneurysms as it compares with a 10 year nonclipping survival period on the basis of two previously published studies (International Study on Unruptured Intracranial Aneurysms and a study by Juvela et al. [36] from Helsinki).

METHODS

Data on 148 unruptured aneurysms in 116 consecutive surgically treated patients were prospectively recorded and retrospectively analyzed. The overall majority were diagnosed with cerebral angiography. Data analyzed included aneurysmal properties and clinical outcomes including surgical related mortalities and morbidities. The observed outcomes were compared with the expected outcome of a 10 year nonclipping survival period if the patient cohort was included in recently reported studies on unruptured aneurysms. More than 1 year follow-up was available in 93.1% (108) of patients and follow-up cerebral angiography was performed in 80% (93) of patients.

RESULTS

Mean age was 53.57 years. There were 25 (16.8%) small aneurysms (less than 7 mm), 70 (47.2%) aneurysms 7 to 12 mm in size, 41 (27.70%) large (13-24 mm), and 12 (8.10%) giant (>25 mm) aneurysms. Posterior circulation aneurysm comprised 13.51%. One hundred forty-three (96.62%) aneurysms were successfully clipped, and 3.37% were either wrapped or later coiled. Surgical-related mortality was 0.82% (1 patient because of air embolism). Surgical related permanent morbidity was 3.44% (4 patients) and transient surgical-related mild morbidities was 7.7% (9 patients). Immediate postsurgical good outcome (Glasgow Outcome Score = 4-5) was 87.93% (102 patients) and 95.68% in 3 months (111 patients). At 1 year, the modified Rankin scale scores were 0 to I = 102, II = 3, III = 2, IV = 1, and V = 0. Residual aneurysms were seen in none of the postoperative angiograms (93 patients). Using the chi method, the comparison of the expected to the observed mortality and morbidity revealed a statistically significant difference in the mortality in favor of surgical clipping (P = 0.034 when compared with the International Study on Unruptured Intracranial Aneurysms and P = 0.05 when compared with the Juvela et al. [36] study). There was no statistically significant difference in the permanent morbidity.

CONCLUSION

Studies on natural history of unruptured intracranial aneurysms suggest 10 year cumulative bleeding-related mortality and severe morbidity of no less than 7.5%. In our study, surgical clipping resulted in an 0.8% rate of mortality and 3.4% permanent morbidity. This suggests that surgical clipping has the potential of a superior outcome to the natural history of patients who have an estimated life expectancy of no less than 10 years.

Endovascular treatment with coils of 149 middle cerebral artery berry aneurysms

PURPOSE

To retrospectively evaluate the immediate and long-term clinical results, as well as the angiographic results, of occlusion of middle cerebral artery (MCA) berry aneurysms with coils.

MATERIALS AND METHODS

This retrospective study had institutional review board approval, and informed consent was obtained. One hundred fifty-four MCA aneurysms in 142 patients were intended to be treated. Complications, patient clinical outcomes, and immediate postprocedural and follow-up angiography results were retrospectively evaluated.

RESULTS

One hundred forty-nine (96.8%) of 154 MCA aneurysms (72 ruptured, 77 unruptured) were occluded with coils in 137 patients (99 women and 38 men; age range, 28-76 years; mean, 48 years). Thromboembolic events occurred in 20 (13.4%) and aneurysm perforation occurred in seven (4.7%) of 149 procedures. Endovascular treatment (EVT) was performed without complications for 121 (81.2%) of the treated aneurysms. For ruptured aneurysms, the treatment-related mortality rate was 6% (four of 72 aneurysms) and the treatment-induced permanent morbidity rate was 1% (one aneurysm). For unruptured aneurysms, the treatment-induced mortality rate was 1% (one of 77 aneurysms) and the procedure-related permanent morbidity rate was 3% (two aneurysms). One hundred five (70.5%) of the 149 aneurysms were examined with follow-up angiography at least once. Recurrences were found for 21 (20%) of the 105 aneurysms that were followed up for a cumulative period of 1564 months (mean, 15 months). Of these 21 recurrent aneurysms, 10 increased in size in the interval between follow-up angiography examinations and 11 remained stable. A second treatment was required for 12 aneurysms, and a third treatment was required for one. After repeat EVT, total aneurysm occlusion was attained for nine aneurysms, and a residual neck was seen in two aneurysms. One recurrent aneurysm was surgically clipped. The nine other aneurysms with small recurrences were not candidates for additional treatment.

CONCLUSION

EVT of MCA aneurysms with coils can be successfully performed without inducing neurologic deficits in most patients with ruptured or unruptured aneurysms.