Embolization of Ruptured and Unruptured Aneurysms with the Contour Neurovascular System—Summary of 106 Cases

Patients and Aneurysms

In the study’s timeframe between 2018 and 2023, 106 patients with 109 aneurysms were retrospectively analyzed from our prospective CNS database. The patient inclusion flowchart is depicted in Fig 1. Median age (range) was 68 years (27–88). In terms of sex, there were 72 women and 34 men. Demographics are summarized in Table 1. Seventy-two patients were treated because of incidental aneurysms, while 34 patients were treated in the framework of aneurysmal rupture with subarachnoid hemorrhage. In 4 cases, retreatment after previous surgery or embolization (1 case of clipping, 1 case of WEB, and 2 cases of previous coiling) was performed. One case was excluded because of off-label use of the CNS in a situation outside of aneurysmal treatment. Further aneurysmal characteristics are summarized in Table 2.

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FIG 1.

Patient selection flow chart.

Findings from specific subgroups of the present analysis were previously published in 2 research studies conducted at our institution.^15,16

Of the 109 aneurysms, 88 were located at a bifurcation, while 21 were sidewall aneurysms. Overall, 89 aneurysms were located in the anterior circulation. Here, 26 aneurysms were localized in the anterior communicating artery (AcomA), 22 in the ICA (of which 9 were at the carotid bifurcation [ICA-T] and 13 along the sidewall of the terminal ICA), 30 at the bifurcation of the MCA, 7 at the posterior communicating artery (of which 5 were at a bifurcation and 2 sidewall aneurysms), and 2 in the pericallosal artery.

Of the 20 aneurysms in the posterior circulation, 17 were located at the basilar tip, 1 in the posterior communicating artery, and 2 in the posterior inferior cerebellar artery.

Mean aneurysm neck size was 3.9 mm (range 1.7–11.6 mm). Mean dome size was 6.7 mm (range 2.5–24.2 mm). Mean aneurysm height was 7.6 mm (range 2.4–26.1 mm). Mean DTN was 1.7 (range 0.93–3.51). Sixty-five aneurysms were considered to have a wide neck with a DTN <1.6.

Among the 106 cases, we found a mean full procedure time of 78 (range 23–209) minutes with a specific Contour time of 33 (range 44–172) minutes. Mean radiation dose of the full procedures was 7886.3 (range 277–197,177) cGy/cm².

Peri- and Postinterventional Antiplatelet Management

In elective cases, patients received a single-dose of aspirin 100 mg and clopidogrel 75 mg before the intervention. After completion of the embolization procedure, aspirin 100 mg was continued for another 4 weeks and then stopped, except for cases where it was continued for nonaneurysm-related reasons.

In the framework of aneurysm rupture, antiplatelet management depended on the occlusion status of the aneurysm. In the case of visual flow-disruption without thrombus formation, no antiplatelet medication was administered. In case of beginning occlusion of the aneurysm or apparent flow disruption, 500 mg of aspirin IV was administered as a single-shot, and then 100 mg of aspirin daily was continued for 4 weeks. In case of instant aneurysm occlusion or excessive thrombus formation, intravenous tirofiban was administered adapted to body weight.

Postinterventional Follow-Up before Discharge

Per our protocol, patients treated in an elective setting were scheduled for postinterventional cranial MRI and CTA. In patients who suffered subarachnoid hemorrhage, imaging follow-up did not follow a specific protocol within 24 hours.

Within 24 hours, 79/106 (74.5%) patients received angiographically assessable imaging, whereby 3 received DSA while 76 received CTA. Here, 54 patients (68.4%) were graded as RRS 1/2.

A total number of 63/106 (59.4%) received an MRI within 24 hours, whereby 38 patients were seen to have spotty DWI lesions. Among these patients, we found a mean number of 4 DWI lesions (range 1–12 lesions).

Follow-Up Results after 6 Months

Follow-up results are displayed in Table 3. For every patient, an appointment for DSA or CTA and MRI was scheduled 6 months after CNS implantation. A total of 69/106 (65%) received angiographically assessable imaging, including 55 patients after elective treatment and 14 patients after subarachnoid hemorrhage. Here, 12 patients received DSA, 10 received CTA, 27 received DSA and CTA, and 20 received CTA and MRI. Upon imaging, 60 patients (86.9%) were graded as RRS 1/2. Four patients (6.6%) were graded as RRS 3a and 5 (8.3%) as RRS 3b. Within 6 months, 5 patients underwent retreatment. Out of the 60 patients rated as RRS 1/2, 29 did not receive any further follow-up.

Follow-Up Results after 12 Months

At 12 months after CNS implantation, angiographically assessable imaging follow-up is available for 44/106 patients (41.5%). Of these patients, 6 received DSA, 20 received CTA, 2 received DSA and CTA, and 16 received CTA and MRI. Initially, 36 were treated in an elective setting, while 8 presented with aneurysm rupture. Here, 36 aneurysms (81.8%) showed an adequate occlusion, 10 after rupture and 26 after elective treatment. Four patients were rated as RRS 3b, whereby 1 was after rupture. Four patients after elective treatment were rated as 3a. One of the patients rated as RRS3b had been retreated.

Follow-Up Results after 24 Months

Angiographic follow-up 24 months after the procedure is available for 30/106 patients (28.3%), 22 after elective treatment, and 8 after aneurysm rupture. Overall, 1 patient received DSA; 1 patient received DSA, CTA, and MRI; 21 patients received CTA; and 7 patients received CTA and MRI. Here, adequate occlusion was seen in 29 patients (96.6%). One patient who initially presented with aneurysm rupture was rated as RRS 3b and subsequently underwent retreatment.

Latest Available Follow-Up beyond 6 Months

The latest available follow-up beyond 6 months was available for 76/106 patients (71.6%, Table 4). Overall, the median angiographic follow-up was 16.6 months (interquartile range [IQR] 8.2–22.0). At the latest follow-up, 69 patients (90.7%) were seen to be adequately occlusion while 3 patients (3.9%) were graded as RRS 3a and 4 (5.2%) as RRS 3b.

Reinterventions

A reintervention was performed in 7/106 cases (6.6%). Here, 5 reinterventions were performed within the first 6 months after CNS implantation due to early recurrences. Two late reinterventions were performed after 12 months and 24 months, respectively.

Of the 7 cases that underwent retreatment, 4 patients initially presented with aneurysm rupture. Three aneurysms were located in the distal internal carotid artery, 1 aneurysm in the basilar tip, 2 in the posterior communicating artery, and 1 in the posterior inferior cerebellar artery. They included 4 sidewall and 3 bifurcation aneurysms. In 2 cases, additional coiling was performed for optimal aneurysm occlusion. These results are summarized in Table 5.

The patient undergoing late reintervention after 12 months had a large ICA aneurysm (5.4 × 13.8 × 14.9 mm; DTN 2.56) that had been primarily treated with CNS implantation in combination with large-volume coiling (CoCoJaMBO). Upon the first follow-up after 12 months, prolapse of both the CNS and coil packet into the aneurysm was evident, which required placement of a flow-diversion stent. Follow-up data after 6 months was not available for this patient.

The patient undergoing late reintervention after 24 months was known to have remaining perfusion of the aneurysmal lumen (RRS 3b) at the 6-month follow-up appointment that was primarily managed with a “watch-and-wait” strategy. Over the course of the 1- and 2-year follow-up, progressive reperfusion was seen, setting the indication for retreatment with a flow-diversion stent.

Complications, Device Failures, and Deaths

In total, a periprocedural complication was found in 8/106 cases (7.5%). Among the 72 patients treated in an elective setting, a complication developed in 4 patients (5.5%). In 2 patients, iatrogenic dissection of the internal carotid artery was seen, which remained without clinical sequelae. One patient developed aphasia after the intervention, which resolved after intravenous thrombolysis, and 1 patient developed light hemiparesis due to basal ganglia infarction, which resolved after 48 hours.

In acute-setting patients, a complication was reported in 4/34 (11.7%) cases. A total of 3 thromboembolic events occurred. In 1 case, acute bleeding from the aneurysm dome was seen after deploying the CNS, requiring additional coiling.

A technical complication was documented in 1 case (0.9%). Here, the CNS accidentally detached after the device was pushed out of the microcatheter. The CNS remained inside the aneurysm dome while the base was still well-perfused. To completely occlude the aneurysm, another CNS with additional coiling (CoCoJaMBO) was placed.

In 5 patients, CNS implantation was intended but not performed as planned. Here, in the case of an ICA aneurysm, the CNS could not be positioned without affecting the origin of the ophthalmic artery, leading to placement of a WEB. In another case of an MCA bifurcation aneurysm, 2 sizes of the CNS could not achieve adequate occlusion, hence, embolization was completed with WEB. In another case of an MCA bifurcation aneurysm, the CNS could not be placed in such a manner to achieve sufficient flow disruption. Thus, embolization was done by coiling. In a case of an AcomA aneurysm, the CNS caused flow-impairment of the A2, and therefore, aneurysmal coiling was performed. In 1 case, both CNS and WEB placement were deemed insufficient. In this patient, flow-diversion stent placement of the parent vessel was needed.

Adjunctive devices were used in 13 cases (12.2%), whereby additional coiling was done in all cases.

Five patients died, whereby 4 deaths occurred as a result of aneurysmal rupture and subarachnoid hemorrhage. Two patients died following the sequelae of severe subarachnoid hemorrhage. One patient experienced fulminant pulmonary embolism 10 days after the procedure. Another patient died because of respiratory insufficiency. One patient treated in an elective setting died after 2 months because of an underlying abdominal tumor.