Stability of ruptured intracranial aneurysms treated with detachable coils: is delayed follow-up angiography warranted?

Progression from Early Minor Recanalization to Major Recanalization in Ruptured Intracranial Aneurysms After Successful Coil Embolization: Risk Factors and Proposal of a Novel Predicting Variable

BACKGROUND

The risk factors for the progression from early minor recanalization to major recanalization are not well established. Herein, we evaluated ruptured intracranial aneurysms (IAs) with minor recanalization within 1 year of coiling and their progression to major recurrence.

METHODS

We retrospectively reviewed our database of coiled IAs and searched for ruptured saccular IAs that were successfully embolized without residual sacs. We selected IAs with minor recanalization confirmed on radiological studies within 1 year of coil embolization. All the IA cases had a follow-up period longer than 36 months based on the radiological results.

RESULTS

Minor recanalization occurred in 45 IAs within 1 year of coil embolization. Among them, 14 IAs (31.1%) progressed to major recanalization, and 31 remained stable. Progression to major recanalization was detected 12 months after minor recanalization in 2 patients, 24 months in 7 patients, and 36 months in 5 patients. Moreover, the progression to major recanalization occurred more frequently in IAs at the posterior location (P = 0.024, odds ratio 11.20) and IAs with a proportional forced area > 9 mm2 (P = 0.002, odds ratio 17.13), which was a newly proposed variable in the present study.

CONCLUSIONS

Our results showed that approximately one third of the ruptured IAs with early minor recanalization after coiling progressed to major recanalization within 3 years. Physicians should focus on the progression of ruptured IAs from minor to major recanalization, especially those with a posterior circulation location and a proportional forced area >9 mm2.

Delayed Progression to Major Recanalization in Coiled Aneurysms with Minor Recanalization at 36-Month Follow-up : Incidence and Related Risk Factors

PURPOSE

The aim was to monitor aneurysms that show imaging evidence of minor recanalization 36 months after coil embolization and to determine the rate and related risk factors of major recanalization during more prolonged observation.

METHODS

A total of 54 patients with 55 aneurysms showing minor recanalization at 36-month follow-up imaging between 2011 and 2013 were retrospectively reviewed. Medical records and radiological data accumulating in the course of extended monitoring (mean 83.9 ± 21.5 months) were assessed. Incidence and average annual risk of progression to major recanalization were then calculated. Univariate and multivariate regression analyses were applied to determine possible risk factors for progression to major recanalization.

RESULTS

In the 55 aneurysms studied 26 showed sustained minor recanalization since month 6 of follow-up, whereas minor recanalization of 29 completely occluded coiled lesions appeared in follow-up images after 6-24 months. Only 8 coiled aneurysms (14.5%) with minor recanalization at 36 months progressed to major recanalization during 219.3 aneurysm-years of observation (3.6% per aneurysm-year), 2 surfacing within 72 months and 6 developing thereafter. Additional embolization was performed in six of these patients. By multivariate analysis, no clinical or anatomic factors were statistically linked to such progression, but younger age showed marginal significance (hazard ratio, HR = 1.076; p = 0.099).

CONCLUSION

Most coiled aneurysms (85.5%) showing minor recanalization at 36 months postembolization proved to be stable in extended observation. Given the low probability but seriousness of delayed major recanalization, careful monitoring is still warranted in this setting but at less frequent intervals (every 2-3 years) beyond 36 months.

Is 3 years adequate for tracking completely occluded coiled aneurysms?

OBJECTIVE

The authors conducted a study to ascertain the long-term durability of coiled aneurysms completely occluded at 36 months' follow-up given the potential for delayed recanalization.

METHODS

In this retrospective review, the authors examined 299 patients with 339 aneurysms, all shown to be completely occluded at 36 months on follow-up images obtained between 2011 and 2013. Medical records and radiological data acquired during the extended monitoring period (mean 74.3 ± 22.5 months) were retrieved, and the authors analyzed the incidence of (including mean annual risk) and risk factors for delayed recanalization.

RESULTS

A total of 5 coiled aneurysms (1.5%) occluded completely at 36 months showed recanalization (0.46% per aneurysm-year) during the long-term surveillance period (1081.9 aneurysm-years), 2 surfacing within 60 months and 3 developing thereafter. Four showed minor recanalization, with only one instance of major recanalization. The latter involved the posterior communicating artery as an apparent de novo lesion, arising at the neck of a firmly coiled sac, and was unrelated to coil compaction or growth. Additional embolization was undertaken. In a multivariate analysis, a second embolization for a recurrent aneurysm (HR = 22.088, p = 0.003) independently correlated with delayed recanalization.

CONCLUSIONS

Almost all coiled aneurysms (98.5%) showing complete occlusion at 36 months postembolization proved to be stable during extended observation. However, recurrent aneurysms were predisposed to delayed recanalization. Given the low probability yet seriousness of delayed recanalization and the possibility of de novo aneurysm formation, careful monitoring may be still considered in this setting but at less frequent intervals beyond 36 months.

Residuals, recurrences and re-treatment after endovascular repair of intracranial aneurysms: A retrospective methodological comparison

OBJECTIVE

Incomplete aneurysm occlusions and re-treatment rates of 52 and 10-30%, respectively, have been reported following endovascular treatment of intracranial aneurysms, raising clinical concerns regarding procedural efficacy. We compare residual, recurrence and re-treatment rates subject to different endovascular techniques in both ruptured and unruptured intracranial aneurysms at a comprehensive state-wide tertiary neurovascular centre in Australia.

METHODS

Medical records, procedural and follow-up imaging studies of all patients who underwent endovascular treatment for intracranial aneurysms between July 2010 and July 2017 were reviewed retrospectively. Residuals, recurrences and re-treatment rates were assessed regarding initial aneurysm rupture status and applied endovascular technique: primary coiling, balloon- and stent-assisted coiling and flow diversion.

RESULTS

Among 233 aneurysms, residual, recurrence and re-treatment rates were 27, 11.2 and 9.4%, respectively. Compared with unruptured aneurysms, similar residual and recurrence (p > .05), but higher re-treatment rates (4.5% vs. 19%; p < .001) were found for ruptured aneurysms. Residual, recurrence and re-treatment rates were: 13.3, 16 and 12% for primary coiling; 12, 12 and 10.7% for balloon-assisted coiling; 14.9, 7.5 and 4.5% for stent-assisted coiling; 91.9, 0 and 5.4% for flow diversion. Stent-assistance and flow-diversion were associated with lower recurrence and re-treatment rates, when compared with primary- and balloon-assisted coiling (p < .05).

CONCLUSIONS

Residuals and recurrences after endovascular treatment of intracranial aneurysms are less common than previously reported. Stent assistance and flow diversion seem associated with reduced recurrence- and re-treatment rates, when compared with primary- and balloon-assisted coiling. Restrained use of stents in ruptured aneurysms may be a contributing factor for higher recurrence/retreatment rates compared to unruptured aneurysms.

MRA versus DSA for the follow-up imaging of intracranial aneurysms treated using endovascular techniques: a meta-analysis

BACKGROUND

Treated aneurysms must be followed over time to ensure durable occlusion, as more than 20% of endovascularly treated aneurysms recur. While digital subtraction angiography (DSA) remains the gold standard, magnetic resonance angiography (MRA) is attractive as a non-invasive follow-up technique. Two different MRA techniques have traditionally been used: time-of-flight (TOF) and contrast-enhanced (CE) MRA. We analysed data from studies comparing MRA techniques with DSA for the follow-up of aneurysms undergoing endovascular treatment. Subgroup analysis of stent-assisted coiling (SAC) and flow diversion (FD) techniques was completed.

METHODS

Comprehensive searches using the Embase, PubMed, and Cochrane databases were performed and updated to November 2018. Pooled sensitivity and specificity were calculated using aneurysm occlusion status as defined by the Raymond-Roy occlusion grading scale.

RESULTS

The literature search yielded 1579 unique titles. Forty-three studies were included. For TOF-MRA, sensitivity and specificity of all aneurysms undergoing endovascular therapy were 88% and 94%, respectively. For CE-MRA, the sensitivity and specificity were 88% and 96%, respectively. For SAC and FD techniques, sensitivity and specificity of TOF-MRA were 86% and 95%, respectively. CE-MRA had sensitivity and specificity of 90% and 92%.

CONCLUSION

MRA is a reliable modality for the follow-up of aneurysms treated using endovascular techniques. While the data are limited, MRA techniques can also be used to reliably follow patients undergoing FD and SAC. However, clinical factors must be used to optimize follow-up regimens for individual patients.

Microneurosurgical Clip Ligation of Acutely Ruptured Cerebral Aneurysm Immediately Preceded by Intentional Subtotal Endovascular Coil Embolization Under a Single Anesthesia: Observations Using a Deliberate Combined Sequential Treatment Strategy in 13 Cases

BACKGROUND

Endovascular coil embolization and craniotomy with clip ligation are the 2 most commonly used treatments for ruptured cerebral aneurysm. Although coiling maintains the advantages of brevity and complete avoidance of brain retraction and manipulation, clipping offers the benefits of decompression of the injured brain and lower rates of aneurysm recurrence. A combined, immediately sequential treatment strategy for acutely ruptured cerebral aneurysm that simultaneously maximizes the advantages of both techniques, while minimizing their respective disadvantages, may be a useful paradigm.

OBJECTIVE

To demonstrate the complementarity of clipping and coiling in acutely ruptured cerebral aneurysm.

METHODS

Patients with ruptured anterior circulation cerebral aneurysm standing to benefit from brain decompression were treated by a combination of coiling and microneurosurgery in rapid succession, under the same general anesthetic. Surgery consisted of clipping of the aneurysm via either craniotomy or craniectomy with expansion duraplasty in all cases, and ventriculostomy in selected cases.

RESULTS

Coil embolization of the ruptured aneurysm was carried out rapidly and improved the efficiency of subsequent clipping by allowing early unequivocal identification of the aneurysm dome and decreased brain retraction, reducing risk of intraoperative rupture and obviating temporary occlusion. All aneurysms were shown eliminated by postoperative cerebral angiography.

CONCLUSIONS

A deliberate combined treatment strategy that uses clipping immediately preceded by subtotal coiling under a single anesthetic may be ideal for selected ruptured cerebral aneurysms, takes advantage of the unique strengths of both techniques, makes both techniques easier, and maximizes opportunity for brain protection against delayed complications in the prolonged aftermath of aneurysmal subarachnoid hemorrhage.

Predisposing factors for recanalization of cerebral aneurysms after endovascular embolization: a multivariate study

BACKGROUND

The recanalization of cerebral aneurysms after endovascular embolization (coiling or stent-assisted coiling) has been a matter of concern.

OBJECTIVE

To systematically evaluate the predisposing factors for cerebral aneurysm recanalization using multidimensional analysis in a large patient cohort.

METHODS

In 238 patients with 283 aneurysms, patient baseline characteristics, aneurysm morphological characteristics, treatment-related factors, and changes in flow hemodynamics after endovascular treatment (coiling or stent-assisted coiling) were compared between the recanalization and non-recanalization groups. Multivariate logistic regression analysis was performed to determine independent risk factors correlated with recanalization.

RESULTS

16 aneurysms treated by coiling recanalized, with a recurrence rate of 18.6%, and 24 recanalized in the lesions treated by stent-assisted coiling, with a recanalization rate of 12.2%. Large aneurysms (>10 mm, p=0.002) and a follow-up interval >1 year (p=0.027) were shown to be statistically significant between the recanalization and non-recanalization groups. For flow hemodynamic changes, three parameters (velocity on the neck plane, wall shear stress on the neck wall, and wall shear stress on the whole aneurysm) showed a relatively lower amplitude of decrease after endovascular treatment in the recanalization group. Interestingly, the velocity on the neck plane and wall shear stress on the neck wall may be elevated after treatment. Specifically, the reduction ratio (RR) of velocity on the neck plane showed significant difference between the groups in the multivariate analysis (p=0.013), and was considered an independent risk factor for recanalization.

CONCLUSIONS

The aneurysm size, follow-up interval, and flow hemodynamic changes, especially the RR of velocity on the neck plane, have important roles in aneurysm recanalization.

Long-term catheter angiography after aneurysm coil therapy: results of 209 patients and predictors of delayed recurrence and retreatment

OBJECT

Aneurysm recurrence after coil therapy remains a major shortcoming in the endovascular management of cerebral aneurysms. The need for long-term imaging follow-up was recently investigated. This study assessed the diagnostic yield of long-term digital subtraction angiography (DSA) follow-up and determined predictors of delayed aneurysm recurrence and retreatment.

METHODS

Inclusion criteria were as follows: 1) available short-term and long-term (> 36 months) follow-up DSA images, and 2) no or only minor aneurysm recurrence (not requiring further intervention, i.e., < 20%) documented on short-term follow-up DSA images.

RESULTS

Of 209 patients included in the study, 88 (42%) presented with subarachnoid hemorrhage. On shortterm follow-up DSA images, 158 (75%) aneurysms showed no recurrence, and 51 (25%) showed minor recurrence (< 20%, not retreated). On long-term follow-up DSA images, 124 (59%) aneurysms showed no recurrence, and 85 (41%) aneurysms showed recurrence, of which 55 (26%) required retreatment. In multivariate analysis, the predictors of recurrence on long-term follow-up DSA images were as follows: 1) larger aneurysm size (p = 0.001), 2) male sex (p = 0.006), 3) conventional coil therapy (p = 0.05), 4) aneurysm location (p = 0.01), and 5) a minor recurrence on short-term follow-up DSA images (p = 0.007). Ruptured aneurysm status was not a predictive factor. The sensitivity of short-term follow-up DSA studies was only 40.0% for detecting delayed aneurysm recurrence and 45.5% for detecting delayed recurrence requiring further treatment.

CONCLUSIONS

The results of this study highlight the importance of long-term angiographic follow-up after coil therapy for ruptured and unruptured intracranial aneurysms. Predictors of delayed recurrence and retreatment include large aneurysms, recurrence on short-term follow-up DSA images (even minor), male sex, and conventional coil therapy.

MRA versus DSA for follow-up of coiled intracranial aneurysms: a meta-analysis

MR angiography is proposed as a safer and less expensive alternative to the reference standard, DSA, in the follow-up of intracranial aneurysms treated with endovascular coil occlusion. We performed a systematic review and meta-analysis to evaluate the accuracy of TOF-MRA and contrast-enhanced MRA in detecting residual flow in the follow-up of coiled intracranial aneurysms. Literature was reviewed through the PubMed, Cochrane, and EMBASE data bases. In comparison with DSA, the sensitivity of TOF-MRA was 86% (95% CI: 82-89%), with a specificity of 84% (95% CI: 81-88%), for the detection of any recurrent flow. For contrast-enhanced MRA, the sensitivity and specificity were 86% (95% CI: 82-89%) and 89% (95% CI: 85-92%), respectively. Both TOF-MRA and contrast-enhanced MRA are shown to be highly accurate for detection of any recanalization in intracranial aneurysms treated with endovascular coil occlusion.

Review of 2 decades of aneurysm-recurrence literature, part 2: Managing recurrence after endovascular coiling

Cerebral aneurysms are treated to prevent hemorrhage or rehemorrhage. Angiographic recurrences following endovascular therapy have been a problem since the advent of this treatment technique, even though posttreatment hemorrhage remains rare. Notwithstanding its unclear clinical significance, angiographic recurrence remains not only a prime focus in the literature but also frequently leads to potentially risky retreatments. The literature regarding aneurysm recurrence following endovascular therapy, spanning 2 decades, is immense and immensely confusing. We review the topic of recurrence following endovascular treatment of cerebral aneurysms in an effort to distill it down to fundamental material relevant to clinical practice.

Five to ten years follow-up after coiling of 241 patients with acutely ruptured aneurysms. A single centre experience

Endovascular treatment has assumed a role of first choice in the management of ruptured intracranial aneurysms. We describe the clinical and morphological data after the treatment of 258 ruptured intracranial aneurysms in 241 patients, in order to evaluate the safety and the efficacy of the endovascular treatment. Two hundred and forty-one patients with saccular ruptured aneurysms were treated at our institution between 2000 and 2005. After the endovascular treatment a clinical and angiographic follow-up was conducted. The clinical follow-up was carried out with a medical examination and telephonic interviews and mRS was used for evaluation. Two hundred and forty-nine acutely ruptured aneurysms were successfully treated and immediately after the endovascular procedure 81.9% of the aneurysms resulted completely occluded, 12.1% had a residual neck and 6% revealed a residual sac. The evolution of each grade was evaluated at six months and two years. During the follow-up we observed five early and one late re-bleedings. Twenty-four patients underwent a second procedure. After the discharge and up to ten years 73.1% of patients had a good clinical outcome (mRS0-1), 8.9% died and the remainder showed moderate-severe disability (mRS2-3). The long-term stability of the anatomical result is a critic-al issue of this approach because eventual re-bleedings may occur even after several months or years. A careful clinical and radiological follow-up for up to two years after the embolization may prevent recurrences but may not be sufficient.