Abstract
The safety and feasibility of using staged flow diverter (FD) for ruptured cerebral aneurysms, in which coil embolization is performed in the acute phase and FD is deployed in the subacute phase, has recently been reported. This strategy requires assuming the rupture point and performing coil embolization. Although vessel wall magnetic resonance imaging (VW-MRI) has been reported to be useful in predicting the rupture point of aneurysms, its use with staged FD has not yet been reported. We report the first case of staged FD with preoperative contrast-enhanced VW-MRI to predict the rupture point for partially thrombosed vertebral artery dissecting large aneurysm involving posterior inferior cerebellar artery (PICA) origin. This approach achieved a very good outcome, not only completely occluding the aneurysm, but also reconstructing the parent artery while maintaining the patency of the PICA.
Keywords: subarachnoid hemorrhage, staged flow diverter, subacute flow diverter, vessel wall imaging
Introduction
Strong wall enhancement on vessel wall magnetic resonance imaging (VW-MRI) is useful for predicting the rupture point in cerebral aneurysms. Such prediction could be useful in staged treatment of ruptured complex intracranial aneurysms with coiling in the acute phase and flow diverter (FD) in the subacute phase, but the combined use of VW-MRI and staged FD has not yet been reported. We here report a case in which we treated with staged FD for a ruptured partially thrombosed vertebral artery dissecting aneurysm (VADA), based on prediction of the rupture point by contrast enhancement on VW-MRI, and achieved a good treatment course.
Case presentation
A 52-year-old man was brought to the emergency room with complaints of worsening headache that he had been aware of for a week, impaired consciousness, left lower extremity paralysis (Manual Muscle Test 3/5), and numbness in the left lower extremity. Computed tomography (CT) showed diffuse subarachnoid hemorrhage and a 20-mm mass anterior to the brainstem (Figure 1(a)). His Glasgow Coma Scale score upon arrival at our institution was 14 (E4V4M6), and he was Hunt and Kosnik grade 3. The patient was endotracheally intubated and underwent cerebral angiography under deep sedation. Right vertebral angiography (VAG) showed fusiform dilatation and saccular aneurysm formation in the right vertebral artery (VA) (Figure 1(b)). The lesion was considered a vertebral artery dissecting aneurysm (VADA) and was involving the posterior inferior cerebellar artery (PICA) origin. Left VAG showed development of the left VA comparable to that of the contralateral VA (Figure 1(c)). Contrast-enhanced VW-MRI (delay alternating with nutation for tailored excitation [DANTE] T1-SPACE), performed on the next day, showed that most of the aneurysm was thrombosed (Figure 2(a) and (b)). Strong contrast enhancement was observed in the intraluminal thrombus (Figure 2(a)), and its contrast enhancement led to the adventitia of the thrombosed aneurysm and then to the anterior medullary cistern where the subacute hematoma was present (Figure 2(c) and (d)). The contrast-enhanced area was predicted to contain a rupture point, and it was determined that hemostasis of the same area could be achieved with coils. Therefore, the treatment strategy was to perform coil embolization for hemostasis first, in the acute stage, and then to reconstruct the dilated VA with preservation of PICA by FD treatment in the subacute phase. On the same day, balloon-assisted coil embolization was first performed under general anesthesia. After implanting six coils, the saccular portion of the aneurysm disappeared almost completely (Figure 1(d)). The next day, CT confirmed that the hematoma had not increased. Aspirin 100 mg/day was introduced. On postoperative day (POD) 12, after preventive treatment for vasospasm, prasugrel was administered as a 20 mg loading dose and continued at 3.75 mg/day the next day. On POD 13, additional treatment was performed under general anesthesia. Right VAG showed regrowth of the aneurysm (Figure 1(e)); thus, additional coil embolization and FD placement (Pipeline Shield; 4.25 × 35 mm) were performed (Figure 1(f) and (g)). MRI on the day after surgery showed only a small spot-like infarct in the right occipital lobe. On the 21st day of hospitalization, the patient was transferred to rehabilitation with a modified Rankin Scale score of 1 due to residual mild sensory disturbance in the left lower extremity. On cerebral angiography at the 6 months follow-up (Figure 1(h)), the aneurysm was completely occluded and the fusiform-shaped dilated VA was also reconstructed. The PICA showed mild vasodilation at the origin but remained well open.
Figure 1.
(a) Axial head computed tomography (CT) at initial examination showing diffuse subarachnoid hemorrhage and a 20-mm mass (black arrow) anterior to the brainstem. (b) Anteroposterior view of the preoperative right vertebral angiogram (VAG) showing fusiform dilatation involving the posterior inferior cerebellar artery (PICA) and saccular aneurysm formation in the right vertebral artery (VA). (c) Anteroposterior view of the preoperative left VAG showing that the development of the left VA is comparable to that of the contralateral VA. (d) Anteroposterior view of the right VAG after initial coil embolization showing almost complete disappearance of the saccular portion of the aneurysm. (e) Anteroposterior view of the right VAG before the second treatment showing regrowth of the aneurysm. (f) Anteroposterior view of the right VAG after second coil embolization and flow diverter deployment, showing additional coil in the regrowth portion of the aneurysm (white arrow). (g) Three-dimensional rotational angiography showing the PIPELINE placed in the right VA, with good adherence. (h) Anteroposterior view of the right VAG 6 months after the second treatment showing complete disappearance of the aneurysm and reconstruction of the dilated VA. The PICA showed mild vasodilation at the origin (white arrow), but remained well open.
Figure 2.
(a) Coronal contrast-enhanced delay alternating with nutation for tailored excitation (DANTE) T1-SPACE before treatment showing a partially thrombosed vertebral artery dissecting large aneurysm. A saccular-shaped blood flow cavity (asterisk) is seen contiguous to the dilated VA. The intraluminal thrombus shows strong contrast enhancement (white arrowhead). (b) A schema of (a), with the asterisk representing the blood flow cavity within the thrombosed aneurysm and the white arrowhead representing the intraluminal thrombus, the thrombus in contact with that blood flow cavity. (R/VA, right vertebral artery; L/VA, left vertebral artery; BA, basilar artery; R/PICA, right posterior inferior cerebellar artery) (c), (d) Sagittal non-enhanced (c) and contrast-enhanced (d) DANTE T1-SPACE before treatment shows the contrast effect leading from the intraluminal thrombus (white arrowhead) to the adventitia of the thrombosed aneurysm (white arrow) and then to the anterior medullary cistern with subacute hematoma (black arrowhead) that shows hyperintensity even on the non-enhanced image.
Discussion
Intracranial VADA are a class of dissections with saccular or fusiform aneurysmal dilation located at the V4 segment of the VA. These are more prone to rupture than similarly located dissections without aneurysmal dilation. 1 Acutely ruptured dissections are unstable and have a rebleeding rate of 71.4% when untreated, based on a study of 42 patients. 2 These rebleeds had a mortality of 46.7%. 2 Therefore, early prevention of rebleeding by using direct surgical or endovascular procedures is essential. 3 Endovascular internal trapping of the dissecting segment using coils is the first choice of treatment for VADAs, particularly in ruptured cases. 3 However, this procedure carries the risk of medullary infarction, associated with poor postoperative outcomes, with reported incidences of 47% and 38%.4,5 Furthermore, when there is insufficient collateral flow or major branches, such as the PICA, are involved, parent artery preservation is paramount. 6 FD device provides a novel treatment option for such devastating aneurysms, by wall reconstruction and aneurysmal sac thrombosis at a later stage. 6 This case was PICA involving VADA, and we thought that FD treatment was appropriate because of the parent artery reconstructions. FD device in acute SAH from posterior circulation dissecting aneurysms has shown efficacy in small series, 6 although its use in acutely ruptured aneurysms remains uncertain, due to the need to initiate dual anti-platelet therapy (DAPT). 7 Furthermore, FD cannot immediately obliterate the aneurysm, while DAPT may further negatively potentiate periprocedural aneurysmal rerupture, and complicate the treatment course, with patients requiring subsequent invasive procedures. 7 To address ruptured aneurysms safely and effectively, “staged FD” has been proposed, in which coiling is performed in the acute phase to reduce early rebleeding risk, followed by planned FD treatment in the subacute phase, once the patient is stabilized and able to tolerate DAPT.7–9 To use this strategy, it is important to presume most likely point of rupture and coil embolize it during the acute phase.8,9 However, in VADA, it is difficult to identify the rupture point, due to the morphology of the aneurysm, and no reports of treatment VADA using staged FD are available. It has already been reported that strong wall enhancement on VW-MRI in ruptured cerebral aneurysms is useful for identifying the rupture point. 10 Mechanisms of strong enhancement of ruptured aneurysms are thought to be stagnation of the contrast material, endothelial damage, or inflammation within the aneurysmal wall. 10 In our case, the preoperative contrast-enhanced VW-MRI predicted that the rupture point would be included in the area with contrast effect. Staged FD was then performed. Not only was the aneurysm occluded, but the PICA was preserved and the dilated VA was reconstructed. Thus, this report shows that using VW-MRI to predict the rupture point when performing staged FD, as in this case, is very useful.
Conclusion
This case illustrates that, when performing staged FD for cerebral aneurysms, it is very useful to predict the rupture point by using VW-MRI.
Acknowledgments
We are very grateful to Yuta Urushibata of Siemens Japan K. K., John Grinstead and Sinyeob Ahn of Siemens Healthineers for providing the prototype sequence.
Footnotes
The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Akira Ishii—Payment for educational lectures and advisory board: Medtronic.
Funding: The author(s) received no financial support for the research, authorship, and/or publication of this article.
Ethical statement
Consent for publication
Consent was obtained from the patient.
ORCID iDs
So Matsukawa https://orcid.org/0000-0002-1816-8632
Masakazu Okawa https://orcid.org/0000-0002-5414-1293
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