Rerupture of coil-embolized aneurysm during long-term observation. Case report

Three-dimensional aneurysm volume measurements show no correlation between coil packing density and recurrence

Objective

Endovascular treatment is the mainstay therapy for brain aneurysms. About 15% of patients need re-treatment within six months due to early recanalization. In this study, we investigate risk factors associated with treatment failure.

Methods

This retrospective cohort study includes endovascularly treated aneurysm cases between July 2012 and December 2015 at the University of California Davis Medical Center with pre-treatment and early post-treatment imaging. Thin cut 3D aneurysm volume rendering was used for morphologic analyses. Univariate and bivariate analyses were conducted to evaluate differences between patients and clinical factors by treatment failure.

Results

Of the 50 patients who met the inclusion criteria, 41 (82.0%) were female, with an average age of 61 years. Most aneurysms were on the anterior communicating artery (40%) or posterior communicating artery (22.0%), and 34 (68%) aneurysms were ruptured. Early treatment failure was observed in 14 (28.0%) of endovascularly treated patients. Raymond-Roy class (RRC) was significantly associated with treatment failure (p = 0.0052), with 10 out of the 14 cases (71.4%) with early recanalization having an RRC of 3. Coil packing density did not associate with aneurysm recanalization (p = 0.61).

Conclusion

In our single institution series, patient characteristics, aneurysm characteristics, or coil packing density did not affect early aneurysm recanalization. RRC was the best predictor of early recanalization; however, further confirmation with additional studies are required. Although this study focused on early treatment failure, late recanalization has been shown with longer follow up. Further investigation into factors associated with late treatment failure will need further investigation. New intrasaccular devices and flow diverters will also likely play a role in reducing recurrence in the future as these treatments gain usage.

Open Surgery for Recurrent Intracranial Aneurysms: Techniques and Long-Term Outcomes

BACKGROUND

After occlusion of an aneurysm, a patient may experience aneurysm regrowth at the same site or develop de novo aneurysms. We present our experience in microsurgery of recurrent aneurysms with analysis of long-term results.

METHODS

The senior authors (R. T. and H. K.) performed recurrent aneurysm clipping on 44 patients at Teishinkai Hospital and Asahikawa Red Cross Hospital in Sapporo, Japan. Operative techniques included clipping only, clipping and protective bypass, trapping of aneurysm with bypass, proximal occlusion, and bypass. Postoperative outcome was analyzed retrospectively using the modified Rankin Scale.

RESULTS

Our series included 10 men (23%) and 34 women (77%), with a mean patient age of 63 years (range, 7-82 years). Before primary treatment, 11 patients (25%) had a ruptured aneurysm, while 33 patients (75%) had an unruptured aneurysm. The mean follow-up time after primary surgery was 7.6 years (range, 0.8-25 years). At our department the treatment of recurrent aneurysm included the clipping in 19 patients (43%), clipping with bypass in 6 patients (14%), aneurysm trapping with bypass in 10 patients (23%), and proximal occlusion and bypass in 9 patients (20%). The mean follow-up time after surgical treatment of recurrent aneurysms stood at 3.5 years (range 0.1-9 years). Altogether, 37 patients (84%) experienced favorable outcomes at last follow-up examination (modified Rankin Scale scores 0 and 1).

CONCLUSIONS

Microsurgery of recurrent aneurysms may be performed safely and effectively, as shown by our study, in which 84% of patients experienced favorable results.

A novel tissue engineering approach using an endothelial progenitor cell–seeded biopolymer to treat intracranial saccular aneurysms

Object

Recurrence after endovascular coiling of intracranial aneurysms is reported in up to 42% of cases and is attributed to the lack of endothelialization across the neck. In this study the authors used a novel tissue engineering approach to promote endothelialization by seeding endothelial progenitor cells (EPCs) within a fibrin polymer injected endovascularly into the aneurysm.

Methods

Experimental aneurysms were created in New Zealand White rabbits and were left untreated, surgically clipped, or embolized with platinum coils, fibrin biopolymer alone, or fibrin combined with autologous cultured EPCs.

Results

In aneurysms treated with EPCs, a confluent monolayer of endothelial cells with underlying neointima was demonstrated across the neck at 16 weeks posttreatment, which was not observed with aneurysms treated using the other methods.

Conclusions

This novel technique may address reasons for the limited durability of standard coil embolization and provides further avenues for the development of improved devices for the care of patients with aneurysms.

Management of Residual and Recurrent Aneurysms After Initial Endovascular Treatment

Background:

Coil instability possibly translating into higher delayed rebleeding rates remains a concern in the endovascular management of cerebral aneurysms.

Objective:

To report on 127 patients with endovascular aneurysmal remnants who underwent re-treatment over an 18 year period.

Methods:

Patients presenting with aneurysm residuals >20% of the original lesion, unstable neck remnants, aneurysmal regrowth, or new aneurysmal daughter sacs were treated by an individualized approach, using both endovascular and surgical techniques.

Results:

Seventy-five aneurysmal remnants (59.1%) were treated by further re-embolization. Standard coil embolization was used in 65 cases, stent-protected coiling in 9 cases, and balloon remodeled coiling in 1 case, respectively. Fifty-two (40.9%) aneurysmal remnants were treated surgically. Standard microsurgical clipping was used in 44 patients, parent artery occlusion or trapping under bypass protection in 5 cases, deliberate clipping of the basilar artery trunk in 2 cases, and aneurysm wrapping in one case, respectively. Mechanisms of aneurysm recurrence were coil compaction in 93 cases and regrowth in 34 cases. A single reembolization was sufficient to occlude 78.7% of recurrences from coil compaction, but only 14.3% of recurrences from aneurysm regrowth.

Conclusion:

The individualized approach resulted in complete occlusion of 114 aneurysms (89.7%), with neck remnants and residual aneurysms detectable in 11 (8.7%) and 2 (1.6%) cases, respectively. Treatment morbidity was 11.9%, without significant differences between surgical (15.6%) and endovascular (9.3%) patients (P = .09). Recurrences from coil compaction were safely treated by re-embolization, whereas recurrences from aneurysmal regrowth may best be managed surgically when technically feasible.

Individual management of recurrent intracranial aneurysms: the Wuxi experience

Recurrent intracranial aneurysms can occur after either surgical clipping or endovascular therapy. In this article, we present a consecutive series of 18 patients who underwent individual treatment for recurrent aneurysms after primary coil embolization or surgical clipping. During an 8-year period between May 1997 and December 2005, 18 patients underwent individual treatment for recurrent aneurysms. Clinical data and imaging studies of the patients were analyzed retrospectively. Out of the 18 patients, 13 had recurrent aneurysms located in the anterior circulation, and 5 had aneurysms of the posterior circulation. Treatment consisted of coiling in 16 patients and clipping in two patients. Of the 18 patients, 15 achieved a good or excellent recovery, two were paralyzed, and one died post-treatment. Both the surgical clipping and endovascular embolization for the treatment of recurrent intracranial aneurysms can achieve very good radiological results with low mortality rates. One of the key points for the successful treatment of this kind of lesions is the proper, individual, and interdisciplinary patient selection.

[MR angiography follow-up of embolized cerebral aneurysms: interobserver agreement]

OBJECTIVE

To determine the interobserver agreement in the interpretation of MR angiography (MRA) studies for surveillance of embolized intracranial aneurysms. To determine whether contrast administration improves interobserver agreement.

MATERIAL AND METHODS

Two experienced neuroradiologists independently reviewed all follow-up MRA studies performed between July 2004 and December 2006 of cerebral aneurysms embolized with coils. All MRA studies included both unenhanced 3D time-of-flight (3D TOF) and contrast-enhanced MRA (CE-MRA) images. Studies were classified as: a) not assessable; b) complete occlusion; c) residual aneurysm. Interobserver agreement for unenhanced and enhanced MRA studies was determined using the kappa statistic. Kappa values were considered insignificant when<0.2, low when between 0.21 and 0.4, and moderate when between 0.41-0.6; values >0.6 were considered good agreement and >0.8 excellent agreement. Significance was set at p<0.005.

RESULTS

We reviewed a total of 200 MRA studies (100 3D TOF studies and 100 CE-MRA studies) performed in 48 patients (25 women, 23 men) at 6, 12, and/or 24 months after embolization. Interobserver agreement was good in both 3D TOF and CE-MRA studies, although it was better in CE-MRA studies (kappa=0.660, p<0.001 and kappa=0.779, p<0.001, respectively).

CONCLUSIONS

Interobserver agreement is good for follow-up MRA studies of embolized intracranial aneurysms. Gadolinium administration improves interobserver agreement.

Noninvasive imaging of treated cerebral aneurysms, part I: MR angiographic follow-up of coiled aneurysms

MRA is emerging as an alternative to conventional catheter based angiography for the assessment of aneurysms after endovascular treatment. Short TE and contrast enhanced MRA techniques can be applied to optimize image quality. We review the available data regarding the application of MR for the assessment of cerebral aneurysms after endovascular therapy.

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.

In vivo intraaneurysmal pressure measurements in experimental lateral wall aneurysms before and after onyx embolization

BACKGROUND

The aim of this study is to measure and compare the in vivo intraaneurysmal pressures of experimental lateral wall aneurysms, before and after onyx embolization. The data of this experiment will carry an important role in forming the scientific basis for the clinical endovascular applications.

MATERIALS AND METHODS

Five experimental lateral wall aneurysms were created by microsurgical techniques in 5 New Zealand rabbits' right common carotid arteries. Onyx embolization was applied to the aneurysms. Intraaneurysmal dome pressure and parent artery measurements before and after the procedure were recorded.

RESULTS

The mean arterial pressure recording in parent artery was 69.2 +/- 2.588 mm Hg under anesthesia. Mean heart rate was 131 beats per minute. The values were in physiologic limits. Meanwhile, aneurysm intradomal pressure recording showed a mean value of 59.2 +/- 5.069 mm Hg. Although there was incomplete occlusion of the aneurysm, intradomal mean pressure was recorded to be 24.4 +/- 8.876 mm Hg. After complete occlusion by onyx, mean intradomal aneurysm pressure was found to be 1.8 +/- 0.836 mm Hg.

DISCUSSION

This study is the first study reporting on intraaneurysmal pressure measurements before and after onyx embolization. The results in this experiment tend to show the adequate intraaneurysmal pressure control of onyx. This is important in the stabilization of the aneurysm to prevent rupture and rerupture. When compared with the findings of GDC coil, onyx embolization seems to be superior in intraaneurysmal pressure control.

CONCLUSION

In this study, it has been shown that onyx embolization decreases the intradomal aneurysmal pressure effectively.

Evaluation of aneurysm stability after endovascular embolization with Guglielmi detachable coils: correlation between long-term stability and volume embolization ratio

The correlation between volume embolization ratio (VER), the percentage of aneurysm volume occupied by coils, and aneurysm stability after endovascular treatment with platinum coils was studied in 86 patients who underwent embolization of 88 cerebral saccular aneurysms with standard platinum coils between March 1997 and January 2003. Radiographic follow up was possible of 62 aneurysms with greater than 70% obliteration on immediate post-procedure angiograms for more than 6 months. Immediate post-procedure evaluation found that 12 of 14 small (<4 mm), 12 of 38 medium (4-<10 mm), and two of 10 large (> or =10 mm) aneurysms had high (> or =25%) VER. In addition, the VER was high in 22 of 40 aneurysms with small (<4 mm) and four of 22 with wide necks (> or =4 mm). Evaluation of 57 aneurysms at 6 months after coil embolization found recanalization in two of 25 aneurysms with high VER and 21 of 32 with low (<25%) VER, indicating that aneurysms with high VER are significantly more stable than those with low VER (p < 0.01). VER strongly affects aneurysm stability, so high VER is desirable and a useful predictor of aneurysm stability.

Repeat Endovascular Treatment in Post-Embolization Recurrent Intracranial Aneurysms

OBJECTIVE:

The purpose of this study was to describe clinical situations requiring repeat embolization in patients previously treated by endovascular coil embolization for intracranial aneurysms, and to report on our experiences of repeat embolization (RE).

METHODS:

A total of 466 patients harboring 522 intracranial aneurysms were treated by endovascular coil embolization at our institution during the period between December 1992 and August 2004. We studied 32 patients who underwent repeat coil embolization (RE) owing to recanalization or aneurysm recurrence. Radiological and clinical data were reviewed to determine the reasons, results, and technical problems of RE.

RESULTS:

Thirty-nine sessions of RE were performed in 32 patients; four patients underwent RE twice and another patient three times. The major reason for RE was asymptomatic aneurysmal recanalization owing to coil compaction and/or loosening. The time interval between RE and the previous embolization was 12 months or less in 27 sessions. Complete or near complete occlusion of the aneurysm was achieved in all cases without procedure-related morbidity or mortality. Radiolucent gaps between the coil masses were observed in 17 cases.

CONCLUSION:

RE is a safe and effective treatment option in cases of recanalized or recurrent aneurysms. Close follow-up evaluation is essential in patients with intracranial aneurysms after coil embolization.

Emerging Concepts in the Treatment of Intracranial Aneurysms: Stents, Coated Coils, and Liquid Embolic Agents

ENDOVASCULAR TECHNIQUES FOR the treatment of intracranial aneurysms are rapidly evolving. Modifications of more traditional coils have been introduced. Such modifications include newer coils coated with various polymers to increase both coil thrombogenicity and degree of aneurysm packing. In addition, newer coil designs aimed at improving the conformability of the coil to the aneurysm have been used with promising preliminary results. The availability of a newer generation of stents specifically designed for intracranial navigation allows for more effective treatment of aneurysms with wide necks, which usually have been considered unsuitable for optimal endovascular treatment. Endovascular alternatives to coil embolization, such as liquid embolic materials, also have been explored for the treatment of intracranial aneurysms, with varying results. We summarize the rationale for use of these newer devices and early clinical experiences. Areas of current research and future directions of endovascular aneurysm treatment also are discussed.

Evaluation of the Stability of Small Ruptured Aneurysms with a Small Neck after Embolization with Guglielmi Detachable Coils: Correlation between Coil Packing Ratio and Coil Compaction

OBJECTIVE:

Because it is difficult to predict the compaction of Guglielmi detachable coils (GDCs) after endovascular surgery for aneurysms, we studied the relationship between the coil packing ratio and compaction. Here, we propose a simple method for the preoperative estimation of coil compaction. Using follow-up angiograms, we studied the timing and degree of coil compaction in small terminal and side-wall aneurysms with narrow necks.

METHODS:

We studied 62 patients with acute ruptured intracranial aneurysms that were small (&lt;10 mm), had a small neck (&lt;4 mm), and were coil embolized with GDC-10s. The aneurysmal volume was calculated using the equation V = 4/3π(a/2) × (b/2) × (c/2), where a, b, and c are the aneurysmal height, length, and width in millimeters, respectively. The coil volume was calculated using the equation V = π(p/2)2 × l × 10, where p represents the GDC-10 coil diameter (0.25 mm) and l is the coil length. We recorded the maximum prospective coil length, L, as that corresponding with the volume of packed coils occupying 30% of the aneurysmal volume. Therefore, L was calculated as L (cm) = 0.3 × a × b × c, and the coil packing ratio was expressed as packed coil length/L × 100. Angiographic follow-up studies were generally performed at 3 months and 1 and 2 years after endovascular surgery. We considered coil compaction exceeding 2 mm as major compaction and recorded minor compaction when it was less than 2 mm of the empty reappeared space in the embolized aneurysm. Aneurysmal location was recorded as terminal or side wall.

RESULTS:

Of the 62 patients, 16 (25.8%) manifested angiographic coil compaction (10 minor and 6 major compactions); the mean coil packing ratio was 51.9 ± 13.4%. The mean coil packing ratio in the other 46 patients was 80.5 ± 20.2%, and the difference was statistically significant (P &lt; 0.01). In all 6 patients with major compaction, the mean packing ratio was less than 50% and all underwent re-embolization after a mean of 24.9 ± 1.1 months. The 10 patients with minor compaction were conservatively treated, and the degree of compaction did not change during a mean period of 24 months. We detected 93.8% of the compactions within 12 months of coil placement. The aneurysm was of the terminal type in 5 of the 6 patients with major coil compaction.

CONCLUSION:

In patients who underwent embolization with GDC-10s of aneurysms that were small and had a small neck, the optimal coil packing ratio could be identified with the formula 0.3 × a × b × c. The probability of coil compaction was significantly higher when the coil packing ratio was less than 50%. To detect coil compaction after embolization, follow-up angiograms must be examined regularly for at least 12 months. To detect major coil compaction in patients with terminal type aneurysms, angiographic follow-up should not be shorter than 24 months.

Morphologic changes in neo-intimal proliferation in an experimental aneurysm after coil embolization: effect of factor XIII administration

We investigated histological changes in aneurysmal orifices after embolization with Guglielmi detachable coils (GDCs) and determined the effects of the wound-healing factor, factor XIII, on promoting intimal proliferation by scanning electron microscopy (SEM). GDC embolization was performed in an experimental model of aneurysm in swine. In the control group (17 aneurysms), the aneurysms were resected immediately after surgery, at 1 and 3 weeks after the procedure. In the factor XIII-administered group (13 aneurysms), the swine received factor XIII postoperatively, and the aneurysms were excised at 1 and 3 weeks. The endothelial cell proliferation changes in the aneurysm orifices in both groups were evaluated by SEM. The histological changes at the orifices began immediately after the procedure, and endothelialization was observed at 1 week. One week after the procedure, the rate of endothelial cell proliferation was significantly higher in the factor XIII group (P<0.05). But no difference was observed at 3 weeks, when endothelialization of the orifices was essentially completed. The process of intimal proliferation after coil embolization was similar to the wound-healing process after vascular intimal injury. Administration of the wound-healing factor, factor XIII, would contribute rapid intimal proliferation and may be effective to facilitate complete obliteration of aneurysms after coil embolization.

Endovascular Treatment of Asymptomatic Cerebral Aneurysms: Anatomic and Technical Factors Related to Ischemic Events and Coil Stabilization

The present study assessed the safety and efficacy of embolization using Guglielmi detachable coils (GDCs) in 100 asymptomatic cerebral aneurysms classified as sidewall (70) or terminal (30) aneurysms according to the parent artery (68 small aneurysms with a small neck, 21 small aneurysms with a wide neck, and 11 large aneurysms). A balloon-assisted technique was used in 49 aneurysms. Immediate angiography revealed that 71 aneurysms were completely obliterated. Transient deficits occurred in 19 patients, permanent deficits in four patients, and one patient died. Most complications occurred during or immediately after treatment and resolved within a few minutes to a few weeks. None of the surviving patients manifested significant morbidity at 1-year follow up. Follow-up angiographic study was performed in 79 aneurysms. Rates of recanalization and progressive thrombosis (total occlusion of the residual aneurysm at follow up) were 11% and 38%, respectively, in sidewall aneurysms, and 26% and 0%, respectively, in terminal aneurysms. Treatment with GDCs was effective for patients with small aneurysms with small necks, the morbidity was acceptable, and progressive thrombosis occurred during the follow-up period. GDC treatment achieved unsatisfactory results in patients with small terminal aneurysms with wide necks and in large aneurysms, because the obliteration rate was low, and the recanalization and complication rates were high. Multivariate analysis showed that complete occlusion was associated with small-necked aneurysms, and ischemic events tended to occur in terminal aneurysms and in aneurysms treated by the balloon-assisted technique.

Recurrent hemorrhage after initially complete occlusion of intracranial aneurysms

Recurrent hemorrhage in the case of incompletely treated aneurysms is well known. The authors present a series of patients in whom rebleeding occurred in spite of totally occluded aneurysms. During a period of 12 years, 1170 patients with intracranial aneurysms were treated using either clipping (n=727) or coiling (n=443). In 11 of them, intracranial rebleeding occurred, in seven of whom routine post-treatment angiography revealed total aneurysm occlusion before the appearance of rehemorrhage. Further analysis focused on these seven patients. Their recurrent aneurysm ruptures happened with a mean latency of 9.5 months (range 21 h-48 months) from initial treatment. All aneurysms belonged to the anterior circulation. Three patients underwent primary clipping, and four experienced coiling first. The intracranial hemorrhages appeared mainly as intracerebral hematomas. The angiographically documented recurrent aneurysm configurations were caused by clip slippage (n=2), coil compaction (n=3), or coil migration/dislocation (n=1). In one case with primary surgery, clip slippage was possible but not confirmed by intraoperative view, because the patient died before therapeutic intervention. Two patients did not undergo therapy because of their poor clinical condition and died. Four of the remaining patients underwent clipping of the recurrent lesions, and one had recoiling. Final outcome was excellent/good in only two patients. The mainly poor outcome after rebleeding was caused by the high incidence of intracerebral hemorrhage.

Clinical and angiographic outcome after Guglielmi detachable coil embolization of intracranial aneurysms

BACKGROUND

Between July 1997 and April 2001, forty patients underwent Guglielmi detachable coil (GDC) embolization of intracranial aneurysms at Wellington Hospital.

METHODS

The clinical notes and imaging were reviewed retrospectively.

RESULTS

Complete initial occlusion was achieved in 28 patients (70%). Eleven patients (27.5%) had small residual neck (>90% occlusion) and one patient (2.5%) had substantial filling of the aneurysm. Follow up angiographic assessment was obtained in 28 patients (70%) of whom 24 patients (85.7%) had no recurrence or stable residual neck and four patients (14.3%) had recurrence or enlargement of the residual neck. Stable occlusion was achieved in 100% of small and medium sized aneurysms and 50% of large and giant aneurysms. Technical complications occurred in 10% including aneurysms perforated in two patients (5%) and presumed parent artery occlusion in another two (5%).

CONCLUSIONS

The findings of the present study demonstrate the safety of GDC embolization. The initial clinical grade at presentation strongly predicted the clinical outcome. Although the number of patients in this study is small, there is evidence that the angiographic outcome is better for small and medium sized aneurysms. Our results are comparable to other published series.

The Underlying Mechanisms of Endovascular Exclusion of Intracranial Aneurysms by Coils. How Important is Electrothrombosis?

SUMMARY

Endovascular coil treatment of intracranial aneurysms is now widely accepted. We discuss some of the arguments for the relative roles of electrothrombosis, spontaneous thrombosis, mechanical filling, haemodynamic effects and surface properties in successful coil treatment. Despite an enormous body of literature, with many theories and much data, there is limited evidence for, or understanding of, the mechanisms by which coil treatment protects against aneurysm rupture. It seems likely that electrothrombosis plays no part.Dense packing is probably important in preventing recurrence. New technologies aiming to encourage endothelialisation and increased connective tissue formation appear promising.

The Role of GDC Embolization as a Second Choice in the Treatment of Ruptured Cerebral Aneurysm. Retrospective Analysis from Mid-Term Outcome

SUMMARY

We investigated the role of GDC embolization as a second choice for the treatment of ruptured cerebral aneurysm. From september 1997 to may 2001, 139 ruptured aneurysms out of 151 consecutive ruptured aneurysms transferred to our hospital were treated by clipping (first choice) or GDC embolization (second choice). Patient selection was decided by more than two neurosurgeons under the policy that GDC embolization is the second choice of treatment. The mid-term (longer than three months) outcome of both group was examined. One hundred and nineteen Ans (BA two, ICparaclinoid one, IC-PC or IC-Ach 36, IC-ant. Wall two, ACoA34, ACA six, MCA38) were treated by clipping (clipping group), 20 Ans (surgical difficulty; BA three, IC-paraclinoid three, VA dissection six, general complications; IC-PC two, IC-dissection one, ACoA four, VAPICA one) by GDC embolization (GDC group) within 24 hours after admission. SAH grade and GOS of each group were Gr1: 35&4, Gr2: 41&5, Gr3: 23&5, Gr4: 11&4, Gr5: 9&2, respectively, and GR: 79&14, MD: 8&3, SD: 11&0, VS: 8&0, D: 13&3 respectively. Good prognosis (better than MD) was gained in 73% of clipping group and 85% of GDC group. No rebleeding was seen in GDC group. GDC embolization for the cases with surgical difficulty or general complication raised the overall outcome. GDC embolization would be suitable for IC-paraclinoid Ans, BA-VA Ans, and ruptured VA dissections. Because of the good clinical outcome gained in the GDC group, GDC treatment would be the first choice of treatment for such aneurysms as geometrically suitable for coiling.

Histological evaluation of endothelial reactions after endovascular coil embolization for intracranial aneurysm. Clinical and experimental studies and review of the literature

SUMMARY

The purpose of this study was to evaluate the role of the endothelial cell reaction after endovascular coil embolization for the treatment of intracranial aneurysms. A scanning electron microscopic (SEM) study of the platinum coil, embolized into a middle cerebral aneurysm in a 35-year-old woman and subsequently removed surgically eight months later, revealed no endothelial coverage on the coil. This finding prompted us to perform experimental studies. In the first in vitro study, endothelial cells from gerbil brain microvessels and canine carotid arteries were co-cultured with either bare-form platinum coils or type-1 collagen-coated coils for up to three weeks, and the endothelial cell population on the coils was ascertained. In the second in vivo study, platinum coils coated with type-1 collagen were delivered endovascularly into canine carotid arteries, while the contralateral side was treated with bare-form coils, and endothelialization over the coil was investigated. SEM studies revealed that no endothelial cells, either from gerbil brain microvessels or from canine carotid artery, were found on the uncoated coils, whereas gerbil endothelial cells began to proliferate on the collagen-coated coils in three days, covering extensively in one week and reaching confluence in two weeks in vitro. The in vivo canine study demonstrated that bare-form platinum coils did not show endothelial coverage until two weeks, but endothelial cells proliferated directly on the collagen-coated coils in three days, and coils were completely covered in two weeks. These results supported the SEM study of our case and several human histopathological reports in the literature in that endothelial cell coverage in the orifice of the intracranial aneurysm is exceptional after endovascular treatment. But if some extracellular matrix, like collagen in our study, is prepared, coverage could be possible, as is seen in a few human cases. Biological modification of the platinum coils, such as collagen coating, is awaited for the better long-term results of endovascular coil embolization without recanalization of the treated intracranial aneurysms.

Post-mortem pathological examination of two patients after intraaneurysmal embolization using guglielmi detachable coils

SUMMARY

We report the histological findings in two patients treated using Guglielmi detachable coils with almost complete occlusion of the aneurysms.Autopsies of these patients were performed one week and one year after GDC embolization respectively. In one aneurysm that was obtained at autopsy one week after embolization, the histological findings revealed coils and an unorganized thrombus-filled aneurysm sac; an incomplete cell-lining on the luminal side of fibrin thrombi in the region of the neck of the aneurysm was recognized. In the other aneurysm in which autopsy was performed one year after embolization, an organized fibrous tissue at the margin of the aneurysmal wall and vascular granulation tissue at the center of the aneurysm were observed. There is a single layer of endothelium covering fibrous tissue in the neck of the aneurysm. We discuss the healing process after GDC treatment.

Embolization with autologous fibroblast-attached platinum coils in canine carotid artery aneurysms: histopathological differences from plain coil embolization

PURPOSE

This study was designed to evaluate the effect of autologous fibroblast-attached platinum coils on the promotion of intra-aneurysmal thrombus organization.

MATERIALS AND METHODS

Sidewall aneurysms were surgically created at common carotid arteries bilaterally in 5 dogs. Fibroblasts were obtained from the skins of the dogs and cultured and attached to unmodified platinum coils in a 5-day coculture. In each animal, one aneurysm was embolized with fibroblast-attached platinum coils (study group) and the other with plain platinum coils of the same size (control group).

RESULTS

All aneurysms were partially occluded; the mean occlusion rate was 67%. The histologic analyses performed 2 weeks after the embolization showed more advanced organization of intra-aneurysmal thrombus in the study group than in the control group (80% versus 53%, P = 0.02). Overgrowth of the organizing tissue and parent artery stenosis did not occur.

CONCLUSION

Our results suggest that autologous fibroblasts delivered with platinum coils could promote the organization of intra-aneurysmal thrombus. Although further research is needed, especially on the potential complications, endovascular treatment using autologous fibroblasts may be applied to aneurysm treatment.

Effects of endothelial injury on the rate of thrombus organization in canine carotid arteries occluded with microcoils

SUMMARY

Thrombus organization in canine carotid arteries occluded with platinum microcoils was studied to determine if endothelial injury created with a Xenon Chloride Excimer Laser (XEL) could acclerate endovascular fibrosis. Ten common carotid artery stumps were created in ten dogs. Each of four stumps were schematically divided into four longitudinally contiguous injury zones (thermal ablation injury, non-ablative injury, proximal and distal non-injury zones) to test the effects of ablative and non-ablative injury and to establish a set of internal controls that would account for proximity to circulating blood at the ostium of the occluded artery. Following XEL irradiation of the endothelium through an arteriotomy, each stump was embolized with microcoils. Four control stumps were subjected to sham laser procedures, and embolized in an identical fashion. Two additional stumps were embolized in the absence of sham surgery. Angiographic, gross and histologic analysis was performed after four weeks. Specimens of freshly clotted whole blood mixed with microcoils were used as an additional control. In irradiated stumps and non-irradiated stumps (sham and embolization only), angiography revealed no evidence of coil compaction or recanalization. In all irradiated stumps the thermal ablation zone contained fibrous tissue and neovascularity without unorganized thrombus. The other zones in the irradiated stumps were indistingnishable from each other and from all zones in the non-irradiated sham stumps, containing primarily unorganized thrombus. Stumps embolized in the absence of sham surgery were filled with material that was grossly and microscopically identical to specimens of freshly clotted whole blood containing microcoils. The results indicate that thermal ablation injury of the endothelium accelerates thrombus organization in canine carotid arteries occluded with platinum microcoils.

Neurosurgical management of intracranial aneurysms previously treated with endovascular therapy

OBJECTIVE

With the increased use of endovascular therapy, an increasing number of patients with incompletely treated intracranial aneurysms are presenting for further surgical management. This study reviews our experiences with such patients.

METHODS

During a 7-year period, 38 patients with 40 intracranial aneurysms who were initially treated with endovascular therapy underwent surgical obliteration of refractory or recurrent lesions. All patients were recorded in a prospective registry, and their clinical data and imaging studies were analyzed retrospectively.

RESULTS

Twenty-six anterior and 14 posterior circulation aneurysms were treated. Four aneurysms were on the cavernous internal carotid artery, 13 were on the distal internal carotid artery, 6 were on the anterior communicating artery complex, 2 were on the middle cerebral artery, 3 were on the posteroinferior cerebellar artery, 1 was at the vertebrobasilar junction, 3 were on the superior cerebellar artery, 4 were at the basilar apex, 2 were on the posterior cerebral artery, and 1 was on the distal vertebral artery. Two pseudoaneurysms-one on the petrocavernous segment of the internal carotid artery and one on the distal VA-also were treated. The median time until recurrence was 6 months. Thirty-one aneurysms were clip-ligated, and six were treated with trapping. Three extracranial-intracranial bypasses were performed. One aneurysm was treated with muslin wrapping. Two aneurysms required the use of surgical approaches that involved hypothermic circulatory arrest. Nine aneurysms required coil mass extraction and/or complex vascular reconstruction to complete lesion obliteration. All aneurysms except the single wrapped aneurysm were successfully excluded from the intracranial circulation. Two deaths occurred as a result of the operative procedures, and another patient died as a result of subarachnoid hemorrhage-induced massive myocardial infarction. Ultimately, 86.8% of patients achieved an excellent or good recovery.

CONCLUSION

With endovascular therapy assuming an increasing role in the treatment of patients with intracranial aneurysms, more lesions that are refractory to initial treatment will require surgical management. Our experience indicates that good results are attainable, although technical challenges are frequently encountered.

5-year Angiographic and Clinical Follow-up of Coil-embolised Intradural Saccular Aneurysms. A Single Center Experience

SUMMARY

The purpose of the paper is the follow-up of embolised intradural saccular Arterial Aneurysms (AA), excluding giant, dissecting, inflammatory, fusiform or AA associated to BVAM. Since its introduction in 1991, the Guglielmi Detachable Coil has offered protection against aneurysmal rebleeding in the critical few days and months after SAH regardless of the grade. A number of questions remain: is complete angiographic obliteration necessary at first embolisation? What duration of clinical / angiographic follow-up (FU) is required to ensure the risk of haemorrhage has been eliminated? What is the long-term protection against rebleeding? One hundred and two patients with 160 intradural saccular AA embolised before april 1997 were selected for this study. They had at least 5-yrs clinical FU, of which 22 patients had a mid- term (3 years) and 45 patients had a 5-year or more angiographic FU (mean 67,7 months per patient). Twenty-eight embolised AAs with 100% occlusion at 1 year, remained unchanged on the 5-year angiograms. A further 14 patients with complete occlusion at 1 year showed persisting complete occlusion on angiogram at 3-years FU, which in our series means that complete occlusion after the first year post-embolisation implies that the aneurysm will remain completely occluded. All secondary spontaneous thromboses (27.6% of cases), occurred during the first year pos- embolisation. In six patients with subtotal or partial occlusion no change was seen for three consecutive years of FU; none showed later change at 5-year angiography. Below 80% occlusion our series does not provide enough information but we consider the situation instable. No mortality related to the procedure was observed in the unruptured AA group.No bleeding or re-bleeding has occurred since the beginning of our experience (1993) in saccular AA treated by GDC-Coil. Coil-embolisation of properly selected patients is effective in protecting against bleeding or re-bleeding at short and long-term with stable morphological results provided a strict follow-up control is established at short term.

Complementary management of partially occluded aneurysms by using surgical or endovascular therapy

OBJECT

The authors present a series of patients in whom partially occluded aneurysms were retreated using complementary surgical or endovascular therapy.

METHODS

During a period of 18 months, 301 patients with intracranial aneurysms were treated using either clip application (171 patients) or endovascular embolization with Guglielmi Detachable Coils ([GDCs] 130 patients). Routine posttreatment angiography studies revealed residual aneurysms in 21 of these patients, nine of whom were retreated using an endovascular or surgical method, with a mean treatment latency of 1.2 months. Four patients underwent primary surgical clip application, whereas five patients experienced GDC packing first. Among patients in the surgical group, the residual aneurysm neck was small and total elimination of the aneurysm was achieved by packing in GDCs. In patients in the endovascular group the authors incompletely packed the aneurysm because of its wide neck or fusiform component in two patients, perforation of a very small aneurysm in one patient, and coil dislocation in another patient. Typical coil compaction occurred in one case. Complete clip application was achieved in all patients. There was no complication in any patient due to the second treatment modality. Final outcome was excellent or good in six and fair in three.

CONCLUSIONS

Following clip application or endovascular embolization of intracranial aneurysms, the use of complementary surgical or endovascular management is successful and associated with low morbidity.

Postprocedure ischemic events after treatment of intracranial aneurysms with Guglielmi detachable coils

OBJECT

Ischemic stroke or transient ischemic attack (TIA) may occur after the treatment of intracranial aneurysms with Guglielmi detachable coils (GDCs). The purpose of the present study is to investigate possible risk factors for thromboembolic events and to determine their frequency and time course.

METHODS

The records of 178 consecutive patients with 193 treated intracranial saccular aneurysms were reviewed. A total of 159 GDC procedures were performed to treat 143 aneurysms in 133 of those patients who were in good neurological condition, allowing clinical detection of postprocedure ischemic events (TIA or stroke). The association of clinical, anatomical, and pharmacological factors with intraprocedure intraarterial thrombus and with postprocedure ischemic events was investigated by using uni- and multivariate analyses. Thrombus protruding into the parent artery was noted during six of 159 GDC procedures, resulting in a clinical deficit in one patient. No factor was associated with intraprocedure intraarterial thrombus. Ten postprocedure ischemic events occurred in nine patients. Seven events occurred within 24 hours, and three events occurred between 24 hours and 58 days. Aneurysm diameter and protruding coils were significant independent predictors of postprocedure ischemic events in multivariate analysis (both p = 0.02). The actuarial risk of stroke was 3.8%.

CONCLUSIONS

Larger aneurysm diameter and protruding loops of coils are associated with postprocedure ischemic events after GDC placement. It is unlikely that GDC-treated aneurysms retain thromboembolic potential beyond 2 months.

Histological findings in coil-packed experimental aneurysms 3 months after embolization

OBJECTIVE

Knowledge regarding tissue reactions within coil-packed aneurysms is poor. The purpose of this study was to analyze histological changes in a chronic experimental bifurcation aneurysm model that might explain the protective effect of Guglielmi detachable coils.

METHODS

The aneurysms were produced by means of a venous graft pouch at a surgically created bifurcation of the carotid artery in the neck of rabbits. After 3 weeks, embolization with Guglielmi detachable coils was performed in the treatment group but not in the control group (seven rabbits each). At the time of embolization, six of seven treated aneurysms were completely occluded according to radiological criteria. Twelve weeks later, all aneurysms were explanted after final angiography. Histological examinations were performed with coils in situ.

RESULTS

Six of seven embolized aneurysms demonstrated complete occlusion in final angiography. But gross pathology revealed that all specimens had differently sized open cavities between the coils. In only two cases, these spaces were very small and the aneurysmal sacs were filled with coils and tissue by more than 90%. Light microscopy demonstrated intraluminal granulation tissue and strong chronic inflammatory wall thickening with numerous foreign body cells at the interface between coils and tissue. Coils were partially incorporated into the aneurysmal wall, sometimes close to the surface and occasionally even outside the wall within the surrounding tissue.

CONCLUSION

The protective effect of Guglielmi detachable coil treatment in our chronic experimental bifurcation aneurysms results from formation of intraluminal granulation tissue and wall thickening attributable to chronic inflammation.

Endovascular treatment of basilar artery trunk aneurysms with Guglielmi detachable coils: clinical experience with 41 aneurysms in 39 patients

OBJECT

The authors present a retrospective analysis of their clinical experience in the endovascular treatment of basilar artery (BA) trunk aneurysms with Guglielmi detachable coils (GDCs).

METHODS

Between April 1990 and June 1999,41 BA trunk aneurysms were treated in 39 patients by inserting GDCs. Twenty-seven patients presented with subarachnoid hemorrhage, six had intracranial mass effect, and in six patients the aneurysms were found incidentally. Eighteen lesions were BA trunk aneurysms, 13 were BA-superior cerebellar artery aneurysms, four were BA-anterior inferior cerebellar artery aneurysms, and six were vertebrobasilar junction aneurysms. Thirty-five patients (89.7%) had excellent or good clinical outcomes; procedural morbidity and mortality rates were 2.6% each. Thirty-six aneurysms were selectively occluded while preserving the parent artery, and in five cases the parent artery was occluded along with the aneurysm. Immediate angiographic studies revealed complete or nearly complete occlusion in 35 aneurysms (85.4%). Follow-up angiograms were obtained in 29 patients with 31 aneurysms: the mean follow-up period was 17 months. No recanalization was observed in the eight completely occluded aneurysms. In 19 lesions with small neck remnants, seven (36.8%) had further thrombosis, three (15.8%) remained anatomically unchanged, and nine (47.3%) had recanalization caused by coil compaction. In one patient (2.6%) the aneurysm rebled 8 years after the initial embolization.

CONCLUSIONS

In this clinical series the authors show that the GDC placement procedure is valuable in the therapeutic management of BA trunk aneurysms. The endovascular catheterization of these lesions tends to be relatively simple, in contrast with more complex neurosurgical approaches. Endosaccular obliteration of these aneurysms also decreases the possibility of unwanted occlusion of perforating arteries to the brainstem.

Enhanced formation of fibrosis in a rabbit aneurysm by gelatin hydrogel incorporating basic fibroblast growth factor

OBJECTIVE

This study was undertaken to analyze whether the controlled release of basic fibroblast growth factor (bFGF) can promote intrasaccular thrombosis in an experimental aneurysmal model.

METHODS

Carotid aneurysms were constructed in 80 rabbits with venous pouches and treated by placing gelatin hydrogels into each aneurysm incorporating 0, 25, 50, or 100 microg of bFGF or incorporating 100 microg of bFGF with different water contents. In the controls, the venous pouches either were not treated or were treated with gauze alone. Gelatin hydrogel was used for the controlled release of bFGF into the aneurysms. The formation of fibrosis in the aneurysms was histologically viewed to assess the area occupied by the fibrous tissues at 3 and 6 weeks after the hydrogel application. The effect of the bFGF dose and water content on obliterating the aneurysm by the hydrogels incorporating bFGF was also investigated.

RESULTS

Six weeks after the application of gelatin hydrogels with a water content of 95 wt% incorporating 100 microg of bFGF, the lateral pouch orifice was completely closed, obliterating the aneurysm at the level of tissue appearance, in contrast to hydrogels incorporating lower doses of bFGF and other control agents. The venous pouch aneurysm was histologically occupied with the newly formed fibrous tissue, and the fibrous tissue area and percentage of the aneurysmal lumen occupied by the fibrosis-gauze complex were significantly larger than those of other hydrogel applications (P < 0.05). The neointima tissue was homogeneously covered with a monolayer of Factor VIII-positive cells. The fact that there was no difference in the water content in the fibrosis formation induced by the bFGF-incorporated gelatin hydrogels indicated that the hydrogel biodegradability did not affect the obliteration of the aneurysm.

CONCLUSION

Local controlled release of bFGF stimulated the formation of in vivo fibrosis, resulting in obliteration of the aneurysm. The long-term results of the fibrous organization remain speculative.

Aneurysm clipping after partial endovascular embolization for ruptured cerebral aneurysms

SUMMARY

The aim of this study was to investigate the advantages and disadvantages of a two-stage treatment for ruptured cerebral aneurysms; partial embolization in acute stage followed by clipping in chronic stage of subarachnoid hemorrhage. Between April 1997 and August 1999, twenty ruptured cerebral aneurysms were initially treated endovasculary using Guglielmi detachable coils in our institution. Among them, complete embolization could not be achieved in 6 lesions. For these lesions, subsequent clipping was added. The radiological and operative findings, and outcomes of these cases were retrospectively reviewed. In 1 case, rerupture occurred during the endovascular procedure. Rerupture was not observed in any cases in the postembolization period. In 2 cases, complications related to the clipping but not the endovascular procedure occurred. These complications included impaired visual acuity for unverified reasons, and memory disturbance due to sacrifice of a perforator arising from the anterior communicating artery. In 3 cases, coil extraction was needed during the clipping, because the loops of the coil extended into the residual neck. Complications related to coil extraction were not observed in these 3 cases. Acute partial embolization of ruptured aneurysm appears to be effective for the prevention of subsequent rerupture during the subacute period, in which treatment for vasospasm should be performed, and the clipping procedure. However, in the case of relatively large aneurysms, small arteries or other normal structures behind the aneurysm cannot be observed directly during surgery, because of the immovability of the embolized aneurysm. Further, complete clip closure is impossible when loops of coil herniate into the neck. In such situations, coil extraction with or without resection of the aneurysm might be necessary, and care must be taken not to damage parent artery and surrounding vessels.

Histological Investigation of Endothelial Cell Proliferation on the Coil Surface after Endovascular Treatment Using FactorXIII. Preliminary Results in Swine Model

SUMMARY

Recently, endovascular treatment of coil embolisation has been widely used for obliterating cerebral aneurysms. However, the process of endothelial cell growth within aneurysms to prevent aneurysmal rupture associated with endovascular coil embolisation remains unclear. Fourteen aneurysms were produced in seven matured swine and embolised with Guglielmi Detachable coils (GDCs). The aneurysms were resected either immediately or three weeks after coil embolisation, and subjected to histological and scanning electron microscopic examinations. Blood coagulation factor XIII was administered in four animals on the day of embolisation and on the following four days. These aneurysms were also resected three weeks after the embolisation and investigated histologically. Marked fibroblast proliferation and growth of endothelial cells on the intraluminal surface of the coil were observed more often in the group administered factor XIII than in those not given factor XIII. These results suggest that administration of factor XIII may contribute to more effective aneurysm obliteration during coil embolisation.

Subarachnoid haemorrhage: diagnosis, causes and management

The incidence of subarachnoid haemorrhage (SAH) is stable, at around six cases per 100 000 patient years. Any apparent decrease is attributable to a higher rate of CT scanning, by which other haemorrhagic conditions are excluded. Most patients are <60 years of age. Risk factors are the same as for stroke in general; genetic factors operate in only a minority. Case fatality is approximately 50% overall (including pre-hospital deaths) and one-third of survivors remain dependent. Sudden, explosive headache is a cardinal but non-specific feature in the diagnosis of SAH: in general practice, the cause is innocuous in nine out of 10 patients in whom this is the only symptom. CT scanning is mandatory in all, to be followed by (delayed) lumbar puncture if CT is negative. The cause of SAH is a ruptured aneurysm in 85% of cases, non-aneurysmal perimesencephalic haemorrhage (with excellent prognosis) in 10%, and a variety of rare conditions in 5%. Catheter angiography for detecting aneurysms is gradually being replaced by CT angiography. A poor clinical condition on admission may be caused by a remediable complication of the initial bleed or a recurrent haemorrhage in the form of intracranial haematoma, acute hydrocephalus or global brain ischaemia. Occlusion of the aneurysm effectively prevents rebleeding, but there is a dearth of controlled trials assessing the relative benefits of early operation (within 3 days) versus late operation (day 10-12), or that of endovascular treatment versus any operation. Antifibrinolytic drugs reduce the risk of rebleeding, but do not improve overall outcome. Measures of proven value in decreasing the risk of delayed cerebral ischaemia are a liberal supply of fluids, avoidance of antihypertensive drugs and administration of nimodipine. Once ischaemia has occurred, treatment regimens such as a combination of induced hypertension and hypervolaemia, or transluminal angioplasty, are plausible, but of unproven benefit.

Electromicroscopic Investigation of the Efficacy of FactorXIII for Coil Embolization in Experimental Aneurysms. Preliminary Report

SUMMARY

In recent years, endovascular treatment has often been used to treat cerebral aneurysms. Basic investigation to elucidate the process of endothelial cell growth within aneurysms is a crucial problem.We performed elecrtro-detachable coil embolization in aneurysms under administration of blood coagulation factorXIII, a wound-healing accelerator, and examined changes in endothelial cells on the surface of the inserted coil with a scanning electron microscope. Experimental aneurysms produced in animals were treated by coil embolization and histological changes in embolized coil after the treatment of factorXIII were investigated. Aneurysms were produced in four matured swines under general anesthesia and coil embolization was performed with a elecrtro-detachable coil. The aneurysms were resected immediately and 3 weeks after coil embolization, and investigated histologically with a scanning electron microscope. Seven animals were administrated with blood coagulation factorXIII on the day of embolized and the following 4 consecutive days. These aneurysms were also resected 3 weeks after embolization and investigated histologically. More marked fibroblast proliferation and growth of endothelial cells on the surface of luminal side of embolized coil were seen in the aneurysms in the group administrated with factorXIII than in aneurysms treated without factorXIII. More effective and sufficient coil embolization can be obtained by administration of factorXIII.

Correlation of magnetic resonance imaging and histological findings in a large basilar tip aneurysm after coil embolization--case report

A 73-year-old female with a large basilar tip aneurysm underwent endovascular coil embolization with interlocking detachable coils (IDCs). The patient subsequently died of pneumonia 25 days after the embolization, and the aneurysm specimen was obtained at autopsy. Histological examination showed that the intraaneurysmal structure consisted of three layers. The outer layer was mildly organized thrombus surrounding the coils, the middle layer was disorganized clot, and the inner layer consisted of fresh blood clot. Gradient-echo magnetic resonance (MR) imaging taken before death had demonstrated a central region of high intensity and a peripheral low intensity region corresponding to the inner and middle-outer layers of the aneurysm, respectively. Intraaneurysmal placement of IDCs leads to the formation of a clot surrounding the coils. However, clot formation may be inadequate where the packing of the IDCs is incomplete. Comparison of the MR imaging and histological findings in this case show that gradient-echo MR imaging can assess thrombus and residual blood flow within the aneurysm.

Growth factors stimulate neointimal cells in vitro and increase the thickness of the neointima formed at the neck of porcine aneurysms treated by embolization

BACKGROUND AND PURPOSE

Growth factors (GFs) may favor the healing of aneurysms treated with endovascular techniques by stimulating neointima formation.

METHODS

Bilateral carotid aneurysms were constructed with venous pouches in 50 pigs and embolized intraoperatively with collagen sponges with and without GFs (platelet-derived growth factor-BB [PDGF-BB] 0.15 or 1.5 microg or transforming growth factor-beta(1) [TGF-beta(1)] 60 or 600 ng) in each animal. DNA synthesis, cell proliferation, and collagen secretion assays were performed to assess the in vitro effects of GFs on neointimal cells harvested from the treated aneurysms. (125)I-PDGF-BB was used to study in vivo GF release from sponges. The thickness of the neointima at the surface of the sponges was measured 2 weeks after surgery. Since porcine aneurysms tend to heal after collagen sponge embolization, this experiment was repeated in dogs, which have shown a propensity for recurrence with the same technique, with 600 ng TGF-beta(1) or platelet extracts.

RESULTS

PDGF-BB stimulated DNA synthesis and cell proliferation, while TGF-beta(1) strongly increased collagen synthesis of neointimal cells in vitro. Clearance of (125)I-PDGF-BB from the sponges followed a biphasic curve, with 1.5% of exogenous PDGF-BB remaining at 1 week. The local delivery of PDGF-BB (0.15 or 1.5 microg) and TGF-beta(1) (600 ng) significantly increased neointimal thickness at the neck of porcine aneurysms, while 60 ng of TGF-beta(1) had no demonstrable effect. TGF-beta(1) (600 ng) or platelet extracts had no influence on canine aneurysms.

CONCLUSIONS

PDGF-BB and TGF-beta(1) can stimulate neointimal cells in vitro and neointima formation in vivo, but TGF-beta(1) and platelet extracts do not compensate for deficient thrombosis in canine aneurysms. Effects on the long-term results of embolization remain speculative.

Early aneurysm recurrence after technically satisfactory Guglielmi detachable coil therapy: is early surveillance needed? Case report

Guglielmi detachable coil (GDC) therapy was initially intended as a treatment for select patients harboring aneurysms deemed to be at high risk for clip ligation. As experience with the technique has grown, many centers are now offering GDC therapy as a primary treatment to patients who are also good surgical candidates. The authors report a case in which a ruptured anterior communicating artery aneurysm recurred within 2 weeks of a technically satisfactory GDC procedure. The patient subsequently underwent successful surgery for clip ligation of the lesion. This is the earliest reported recurrence of an aneurysm after angiographically confirmed successful GDC therapy and underscores the need for performing early control angiography in patients undergoing this procedure.

Long-term histopathology of intracranial aneurysms after endovascular treatment with coils. Report of two cases with ultrastructural evaluations by scanning electron microscopy

We describe the results of electron microscopic examination in two patients with ruptured intracranial aneurysms who were successfully treated by endovascular coil embolization. The aneurysms were seen completely occluded on the follow-up angiograms. Autopsies of these patients were performed five and 26 months after endovascular treatment when they died of pneumonia and thalamic hemorrhage, respectively. The aneurysms were densely filled with the coils, which were readily identified through the thin and transparent wall of the aneurysmal dome. The orifice of the aneurysm was completely occluded so that macroscopically the coils were not directly visualized through the orifice. To examine any evidence of endothelialization across the orifice of the aneurysms, scanning electron microscopic examination was performed. In both cases, evidence of well regenerative endothelialization was observed across the aneurysmal orifice, being contiguous with the endothelial layer of the adjacent parent vessels. These ultrastructural findings indicate that the aneurysms are completely isolated from the lumen of the parent artery by a continuous lining of the regenerated endothelial cells following the endo vascular treatment with coils, and further suggest that aneurysms have a potential of being cured permanently by this treatment modality. This is, to the best of our knowledge, the first report in humans verifying a complete endothelialization of the luminal surface at the aneurysmal neck after coil embolization, as evidenced by scanning electron microscopy.

Clinical and angiographic results of endosaccular coiling treatment of giant and very large intracranial aneurysms: a 7-year, single-center experience

OBJECTIVE

To evaluate whether the objectives of surgical treatment, i.e., prevention of aneurysmal rebleeding, relief of aneurysmal mass effect, and prevention of embolic complications, are met by endosaccular coiling treatment applied to giant and very large wide-necked aneurysms.

METHODS

Thirty patients with 31 giant or very large aneurysms were considered to show unacceptable risk/benefit ratios for open surgery and were treated using the Guglielmi detachable coil (GDC) method between 1992 and 1998.

RESULTS

With endosaccular GDC treatment, 73.3% of the population experienced excellent to good recoveries (Glasgow Outcome Scale scores of 4 or 5), with a 13.3% procedure-related morbidity rate and a 6.7% procedure-related mortality rate. Two hemorrhaging episodes occurred after GDC treatment (annual bleeding rate, 2.5%; 2 hemorrhaging episodes/79.2 patient-yr). Symptoms related to aneurysmal mass effect were improved for 45.5% of the patients presenting with signs of neural compression. Among 23 patients with 24 aneurysms who were available for angiographic follow-up assessment, complete or nearly complete occlusion was observed for 17 aneurysms (71%; angiographic follow-up period, 24.3 +/- 19.6 mo, mean +/- standard deviation). A single total embolization served as definitive treatment for only 12.5% of the giant aneurysms and 31% of the very large aneurysms.

CONCLUSION

Endosaccular GDC treatment of giant and very large aneurysms was accomplished with procedure-related morbidity and mortality rates comparable to those for open surgery performed by experts. However, because coil stability was unsatisfactory, we suggest that the GDC method should currently be reserved for individuals who are considered poor candidates for open surgery.

Histologic evaluation of platinum coil embolization in an aneurysm model in rabbits

PURPOSE

To characterize the histologic response to platinum coil embolization by using a rabbit aneurysm model.

MATERIALS AND METHODS

Saccular aneurysms were created in New Zealand White rabbits by using vessel ligation with intraluminal elastase incubation. Aneurysms were subsequently embolized by using platinum coils. Subjects were sacrificed at various intervals up to 12 weeks following coil embolization. The aneurysm cavities and adjacent vessels were embedded in methylmethacrylate, were sectioned, and were stained for histologic examination.

RESULTS

Two weeks following coil implantation, aneurysms were filled predominantly with unorganized thrombus. Six weeks following coil implantation, histologic features included complete filling of the aneurysm lumen with either prominent laminated but unorganized thrombus or areas of unorganized thrombus interspersed among areas of cellular infiltration. At 12 weeks following coil implantation, aneurysms were filled with the loosely packed, disordered cells contained within the extracellular matrix. Fibrosis or smooth muscle cell infiltration was not present in any of the 6- or 12-week samples.

CONCLUSION

Platinum coils placed into experimental saccular aneurysms in New Zealand White rabbits failed to elicit a fibrotic response. This model can be used for the testing of biologic modifications of platinum coils aimed at increasing intra-aneurysmal fibrosis.

Acute histologic and ultrastructural study in one case of human basilar tip aneurysm embolised with guglielmi detachable coils

SUMMARY

Histologic findings after Guglielmi detachable coils endovascular embolisation have been studied in experimental aneurysms. Few reports describe histopathologic reactions to platinum coils in humans. In this report we describe gross, light microscopic pathology and scanning electron microscopy study of a ruptured basilar tip artery aneurysm in a patient who died 16 hours following coiling.

Gross and microscopic histopathological findings in aneurysms of the human brain treated with Guglielmi detachable coils

OBJECT

The histopathological characteristics of aneurysms obtained at autopsy or surgery 3 days to 54 months after being treated with Guglielmi detachable coils (GDCs) were assessed.

METHODS

Seventeen aneurysms were obtained at autopsy and one was removed at surgery. Fourteen were examined histologically with the coils in situ. Naked coils embedded in an unorganized thrombus were found in those aneurysms that had been treated with coils within 1 week earlier. An incomplete replacement of the intraluminal blood clot by fibrous tissue and a partial membranous covering at the aneurysm orifice were observed in those aneurysms that had been treated with coils between 2 and 3 weeks prior to examination. One small aneurysm treated 6 weeks before harvesting showed formation of an endothelium-lined layer of connective tissue at the orifice. Collagen-rich vascularized tissue surrounding the coils was found in an aneurysm removed at surgery 54 months after coil implantation. Interestingly, six (50%) of 12 aneurysms (two small, three large, and one giant) that had been deemed 100% occluded on initial angiography showed tiny open spaces between the coils at the neck on gross examination.

CONCLUSIONS

Endothelialization of the aneurysm orifice following placement of GDCs can occur; however, it appears to be the exception rather than the rule. In large aneurysms the process of intraaneurysm clot organization seems to be delayed and incomplete; tiny open spaces between the coils and an incomplete membranous covering in the region of the neck are frequently encountered. Further longitudinal studies are required to establish the spectrum of healing profiles that may direct our efforts in modifying the GDC system to produce a more stable long-term result.

Aneurysm retreatment after Guglielmi detachable coil and nondetachable coil embolization: report of nine cases and review of the literature

OBJECTIVE

Guglielmi detachable coil embolization of cerebral aneurysms is becoming increasingly used to manage certain intracranial lesions based on aneurysm geometry, patient condition, and patient and surgeon preferences. Aneurysm recurrences or incomplete initial treatments are not uncommon, making repeat treatment necessary using either surgical or endovascular techniques.

METHODS

Between January 1993 and June 1998, 1025 cerebral aneurysms were managed by the authors at a single hospital. One hundred twenty-four of these lesions were treated using Guglielmi detachable coils, and one was managed with nondetachable coils. During the follow-up period, eight patients who underwent embolization at our institution and one who underwent embolization elsewhere received repeat treatment. Five were approached surgically, and four underwent re-embolization. All charts and films were reviewed retrospectively to determine patient outcome and clinical success.

RESULTS

No patient in the subgroup of this clinical study suffered a permanent complication from initial aneurysm coiling, no episodes of subsequent bleeding occurred, and no complications resulted from any subsequent therapies. The anatomic results were excellent, and all aneurysms were totally or near totally obliterated.

CONCLUSION

Subtotal initial coil embolization of aneurysms can be managed safely using a variety of surgical and endovascular techniques. Our approach to this predicament, lessons we have learned, and a review of the literature are herein discussed.