Retrospective Review Analysis of Interventional Radiologic Endovascular Coil Embolization versus Neurosurgical Clipping in Management of Intracranial Aneurysms

Introduction

Globally, nontraumatic subarachnoid hemorrhage (SAH) due to ruptured intracranial aneurysm is the most important cause of morbidity and mortality with high-risk outcomes. Ruptured intracranial aneurysm due to nontraumatic SAH presents with clinical symptom of “worst headache of life” and is routinely diagnosed in emergency radiology call on plain computed tomography (CT) scan.¹ Other clinical presentations vary from nausea, vomiting, loss of consciousness, transient motor deficits, convulsion, or seizure, in association with severe headache as prominent feature with neck pain, meningismus, and/or hyperirritability. If clinically suspicious and equivocal on CT scan, lumbar puncture reveals cerebrospinal fluid (CSF) xanthochromia suggestive of SAH.^2,3

Routinely post CT suggestive of SAH, with high suspicion for aneurysmal bleed, contrast-enhanced CT (CECT) cerebral angiogram are performed to search and demonstrate aneurysm. If aneurysm is not demonstrated on CECT angiogram, catheter digital subtraction angiography (DSA) is done as gold standard to rule out the aneurysm. Mostly on catheter DSA, the location, size, site, number, configuration and, if contemplated for endovascular management, the study of relevant vascular anatomy and working angle is done for planning of intervention. If DSA is negative for aneurysm, repeat DSA is advised on follow-up at 7th or 15th day to demonstrate aneurysm if it at all was not demonstrated on previous DSA due to spasm. Depending on the risk evaluation and protocol, either endovascular or neurosurgical (NS) management is contemplated.^4,5 Thereafter clinical evaluations are made with SAH grading scales⁶ and routine investigations under general anesthesia, and the case is planned for interventional radiologic (IR) endovascular coil embolization or NS aneurysm clipping. Hypertension control and peri- and postprocedural management have undergone significant changes and neuro-intensive care unit (ICU) protocol formulations as per recent guidelines and research like the advances in aneurysm management and technology. The recent advances in coil embolization techniques, hardware, and availability of advanced catheter laboratories and biplane as well as instrumentation in NS clipping and advanced neuronavigation software have revolutionized the aneurysm management and outcomes.⁷ Among the two principle streams in management of aneurysm, endovascular approach has been highlighted and has been in limelight than NS approach; however, future studies and interdepartmental studies and registries could shed more light on this controversial aspect in management of aneurysm.^6,8,9 Although sometimes postendovascular management NS backup is required, sometimes it may be necessary to manage the case with hybrid approach, interdisciplinary help or multidisciplinary approach to manage or prevent complications such as vasospasm and its sequelae, intra- or postprocedure hemorrhagic complications and its sequelae as seen on intra- or postprocedure DSA/CT scan/MRI (magnetic resonance imaging), endothelial dysfunction, cerebral edema, hydrocephalus, ischemia, and implementation of various measures for aiding neuroprotection.^9–11 These two commonly used management approaches for aneurysm treatment have their individual merits and demerits.^6,9,12-16 We conducted this retrospective study to analyze and gain experience from our past cases managed at tertiary care super specialty center and serve as baseline pilot study to implement further studies and have insight for future trends in rural hospital setup in management of ruptured intracranial aneurysms aimed to improve and upscale clinical outcomes in these patients.^17–21

Materials and Methods

This was a retrospective observational study conducted in the interventional radiology department of a tertiary care medical college and super specialty hospital situated in a rural area. The patients who presented with either diagnosis of ruptured intracranial aneurysm or nontraumatic SAH who were either later diagnosed on CECT cerebral angiography or on DSA with baseline plain CT suggestive of ruptured intracranial aneurysm (either of anterior or posterior circulation) and underwent management with endovascular coil embolization by IR or NS aneurysm clipping in respective departments of this hospital were included in this study during 2014 to 2018 on the basis of a predefined inclusion and exclusion criteria. Study comprised patients belonging to either of two groups depending on the management they underwent (endovascular coil embolization or NS clipping). Analysis was done for demographic data as well as those pertaining to findings on pre- and/or intra-postprocedure plain CT scans and CECT and/or DSA (as per availability on hospital PACS). Statistical analysis was done by using descriptive and inferential statistics and online calculator Social Science Statistics. Software used in the analysis included SPSS 22.0 and Graph Pad Prism 6.0. For statistical purposes, p < 0.05 was considered as significant.

Results

This study comprised 57 patients in whom demographic data were studied, out of whom 32 underwent IR coiling and 25 underwent NS clipping. For our review analysis, we studied 23 aneurysm clipping cases and 31 aneurysm coiling cases owing to nonavailability of the remaining cases on PACS. Retrospective analysis of cases was done and included in our results based on findings on available pre-/postoperative CT/MRI and/or pre-/post- and intraoperative DSA. Comparative analysis was done in the two groups: NS clipping group and IR endovascular coiling group.

The gender distribution of the studied patients showed that IR endovascular coiling group had 8 males and 24 females whereas NS clipping group had 9 males and 16 females. The overall study population consisted of 29.83% males and 70.18% females in this study. The analysis of age groups of the patients showed that in IR group the most commonly affected age group was 47 to 56 years (25%; 8 cases), followed by 57 to 66 years (21.88%; 7 cases) and 5 cases (15.63%) each in 27 to 36 and 37 to 46 years. The youngest patient belonging to IR group was a 10-year-old girl. In NS group, the most commonly affected age group was 47 to 56 years (28%; 7 cases), followed by 57 to 66 years (24%; 6 cases) and 37 to 46 years (20%; 5 cases). The most common age groups affected were as similar to those in IR group. The youngest case in NS group was a 10-year-old boy. The mean age of patients in IR group was found to be 46.88 years ± standard deviation (SD) 16.59 years, whereas in NS group it was found to be 47.92 years ± SD 15.08 years. The overall mean age was found to be 47.33 years (SD 15.68 years). The age groups were comparable, and there was no statically significant difference in the age groups of patients (►Table 1).

In IR group, the pre- and postprocedure modified Fisher's scale (MFS) value was 53 and 50, respectively, in 31 cases, whereas the same in NS group were 43 and 53, respectively, in 23 cases.

The difference change in MFS for pre- to post-procedure in IR group was small (3) and showed decreasing trend (from 53 to 50 as well as in individual Fisher grade), whereas that in NS group, it was big (10) and showed increasing trends (from 43 to 53 as well as in the individual Fisher grade), thus implying betterment in MFS in IR group and worsening in NS group.

The NS group revealed total of 23 aneurysms clipped, out of which Acom aneurysm cases were highest frequency followed by middle cerebral artery (MCA) aneurysm in anterior circulation (location wise). The Acom aneurysms and female sex of cases were in frequent association in this group.

The IR group revealed total of 31 aneurysms coiled, out of which MCA aneurysms were in highest frequency, followed by both Acom and internal carotid artery (ICA) aneurysms subgroup in anterior circulation (location wise). The association of both Acom and MCA aneurysm cases had dominance of female sex in this group.

In posterior circulation aneurysms in both groups were less in number and had no dominant location although Pcom-PCA aneurysm location had high frequency in combined study population (►Fig. 1; ►Table 2).

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Fig. 1

Gender distribution of the studied cases.

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The comparative analysis for postoperative complication in terms of major stroke/infarction on postprocedure imaging reveals similar number of events with slight difference in presentation territories in both the groups. There were six anterior cerebral artery (ACA) territory infarctions, four MCA territory infarctions, and two PCA territory infarctions in postendovascular coiling cases, whereas five MCA territory infarctions, four ACA territory infarctions, and two PCA territory infarctions with one involving head of caudate nucleus.

The other significant complications in IR group were two intraprocedural aneurysmal ruptures (one Acom and other Pcom aneurysm, both with good outcomes) and two intraprocedural nonresponsive spasms, one nonresponsive ACA occlusion post-coiling, one IVH (intraventricular hemorrhage) case not requiring EVD (external ventricular drainage), while the other IVH case required decompressive craniotomy.

The NS group mostly on imaging revealed four IVH cases. Of them, two required EVD, one required hydrocephalus with ventriculoperitoneal (VP) shunt; 7 cases with craniotomy site thick SDH (subdural hematoma) with pneumocephalus and one with major brain herniation via craniotomy site owing to severe edema and mass effect.

Similar frequencies for cerebral major edema and intraparenchymal hemorrhage were noted in both the groups.

Minor complications in IR group were seen as puncture site hematoma and postoperative minor infarcts whereas in NS group thin SDH at postoperative craniotomy site with pneumocephalus and postoperative minor infarcts were noted.

There was significant difference in pre- and postoperative MFS in both the groups, showing rising trend and overall scale value and frequency difference favoring endovascular IR coil embolization than NS clipping (►Tables 3–6).

Discussion

Nontraumatic SAH is the most common presentation of ruptured intracranial aneurysm requiring multidisciplinary management including interdisciplinary team effort to achieve better clinical outcomes and results. In the past few years, a revolution has occurred in the techniques and technology of management of intracranial aneurysm. Nowadays, endovascular approach is preferred over NS approach owing to minimally invasive and early postprocedure recovery as compared with more recovery time postcraniotomy status in postoperative uneventful cases.²²

The most commonly used approaches for management of ruptured intracranial aneurysms are IR coil embolization approach or NS aneurysm neck clipping, apart from neuro-intensive care (management of hypertension and postoperative triple H therapy, management of vasospasm) and general management for better outcomes.^7,8,10–13

This research was done as pilot study in rural hospital setup as review analysis to compare IR and NS groups and formulate further clinical studies.

In our study, there were more females with intracranial aneurysm, with average age of patients in our study being 47 years with overall high frequency for Acom and MCA aneurysm locations. Suarez et al¹ in their study mention regarding higher risk of intracranial aneurysms to women than men. Connolly et al⁷ also mention in their guidelines paper about female sex as risk factor for intracranial aneurysm and adult age around 50 years as significant cause for aneurysmal SAH. Pierot et al²³ also mention in their paper that Acom aneurysms were most frequently encountered location, followed by ICA and MCA aneurysms. The authors also mention that embolic events are more common in MCA aneurysm. Although clippings have more preference in general overcoiling, in higher age groups coiling was preferred over clipping. They also mention about cases of multiple aneurysms. Similarly in our study we had a dual aneurysm case with aneurysm at the left vertebral artery-PICA origin with another at right MCA bifurcation, managed by coiling both aneurysms with technical success.

Various strategies for management of ruptured aneurysm and SAH, management of intra- and postoperative complication, and preventive strategies have been discussed by Connolly et al,⁷ Fraser et al,⁸ Rabinstein et al,¹⁰ Varelas et al,¹¹ Macdonald et al,¹² Sekhar and Chanda,¹³ and Pierot et al²³ in their papers, which we have been following. Newer guidelines are also implemented time to time in terms of management pre-, peri-, and postoperative periods for achieving better outcomes with interdepartmental cooperation, interdisciplinary management, and supportive neurointensivist and neurosurgeon and dedicated paramedical staff. We had two cases (one each of Acom and Pcom aneurysms) with intraoperative aneurysm rupture during planned coil embolization who were managed successfully intra- and postoperatively with good outcomes and were uneventful on discharge and follow-up. Both cases were nonhypertensive and required tailored dose management for nimodipine and neurointensivist care.^7,8,10–13

The studies by Oliveira et al,²⁴ Frontera et al,²⁵ Kramer et al,²⁶ and Dengler et al²⁷ have highlighted and compared relevance of various SAH grading scales and its clinical significance. The prognostic utility of these scales and their individual as well as comparative significance have been vastly discussed and studied. In our study we have taken into consideration the results of MFS and its outcomes in review analysis of IR and NS groups.^24–27. Similar to conclusions by Kramer et al²⁶ and Dengler et al,²⁷ in our study, there was significant incremental rise in the MFS in the NS versus IR groups, wherein there was absolute rise in MFS score (postoperative vs. preoperative) as well as in individual comparitive case-wise MFS grading in the NS versus IR group, which yields to conclude that endovascular coil embolization outcomes are better than NS clipping in our review analysis; higher MFS group score and grades are at increased risk for vasospasm and delayed infarction, which in-turn lead to both poor neurologic and prognostic outcomes.

Conclusion

Both endovascular and NS groups had comparable major strokes and complications, though there were higher grades and incremental MFS score and greater difference in MFS score in NS aneurysm clipping group than endovascular aneurysm coiling group. Although minor complications were comparable in both the groups; prolonged morbidity and hospital stay were observed in NS group owing to craniotomy in comparison to coil embolization group (uneventful intraoperative group cases). To conclude, we recommend prospective studies incorporating the functional clinical outcomes scale: Modified Rankin's Scale (MRS)²⁷ along with the Modified Fisher's Scale (MFS)²⁸ for further comparative study in both groups in terms of clinical and prognostic outcomes for management of ruptured aneurysmal SAH.