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Treatment of bilateral vertebral artery dissecting aneurysms presenting with subarachnoid hemorrhage remains challenging as bilateral deconstructive procedures may not be feasible. In this case series, we describe our approach to their management and review the pertinent literature.
A retrospective review of our prospectively collected database on aneurysms was performed to identify all patients with acute subarachnoid hemorrhage in the setting of bilateral intradural vertebral artery dissections (VAD) encompassing a period from January 2000 and March 2012.
Four patients (M/F=2/2; mean age, 51.5 years) were identified. In two cases the site of rupture could be identified by angiographic and cross-sectional features; in these patients deconstructive treatment (proximal obliteration or trapping) of the ruptured site and reconstructive treatment of the unruptured site (using stents and coils) were performed. In the patients in whom the site of hemorrhage could not be determined, bilateral reconstructive treatment was performed. No treatment-related complications were encountered. Modified Rankin scale scores were 0–1 at discharge, and on follow-up (mean 63 months), no recurrence, in-stent thrombosis or new neurological deficits were encountered.
We believe that single-stage treatment in patients with bilateral VAD is indicated: If the site of hemorrhage can be determined, we prefer deconstructive treatment on the affected site and reconstructive treatment on the non-affected site to prevent increased hemodynamic stress on the unruptured but diseased wall. If the site of dissection cannot be determined, we prefer bilateral reconstructive treatment to avoid increasing hemodynamic stress on the potentially untreated acute hemorrhagic dissection.
Spontaneous bilateral vertebral artery dissections (VADs) are rare and account presumably for less than 10% of all vertebral artery dissections.1–3 Hemorrhagic dissections warrant early treatment given a high likelihood of re-rupture. If hemorrhages occur in the presence of bilateral VADs, bilateral deconstructive techniques such as proximal coil obliteration or internal trapping may not be possible because of insufficient collaterals from the anterior circulation. Unilateral occlusion only is in our opinion not indicated either, as the increased hemodynamic stress in the contralateral vertebral artery (VA) may lead to expansion or rupture of the untreated dissection,4–6 especially in cases where it is not possible to determine which site had ruptured. Although staged bilateral vertebral artery obliteration7 in the case of sufficient collateral flow from anterior circulation can be performed, interval hemorrhage or progressive aneurysm enlargement may occur. With the continued advances of stent technology, stent-related reconstructive techniques for ruptured or unruptured VADAs are emerging as a promising alternative to deconstructive techniques.8–10 In the following we present our treatment strategy for bilateral VADs in the context of acute subarachnoid hemorrhage (SAH) based on four patients, and we review the pertinent literature.
A retrospective review of our prospectively collected database on aneurysms was performed to identify all patients with acute SAH who harbored bilateral VADs in our institute between January 2000 and March 2012. A total of four consecutive patients (male:female=2:2; mean age, 51.50 years; range, 38 to 58) harboring eight spontaneous VADAs (Hunt-Hess grade I in three, II in one) were identified and retrospectively analyzed. VADAs were diagnosed when angiographic imaging revealed fusiform or irregular dilation with or without stenosis in the vertebral artery. Based on the location of aneurysms relative to the posterior inferior cerebellar artery (PICA), the VADAs were classified as PICA-involving (n=4) and not PICA-involving (n=4) (see Table 1 for patient and aneurysm characteristics).
As patients were referred to our institution from outside hospitals, time lag between SAH and treatment varied from two to 15 days. All patients received a loading dose of aspirin (300mg) and Plavix (300mg) administered orally or anally11 two hours before the procedure. All patients were heparinized during the procedure, and, after the procedure heparin was not reversed. In all cases, our strategy was to perform bilateral treatment during the same setting. If the rupture site could be identified without doubt based on cross-sectional and angiographical characteristics, we aimed to perform a deconstructive treatment of the dissected site followed by reconstructive treatment of the unruptured site (two patients). If the site of acute dissection could not be identified, bilateral reconstructive techniques were used (two patients).
A 6F guiding catheter (Envoy Max ID; Cordis, Johnson and Johnson Medical, Miami Lakes, FL, USA) was inserted into the VA inferior to the atlantal loop. For deconstructive treatment, the stent delivery catheter was placed at the portion distal to the dissection, and then the dissection was superselected using an Echelon10 microcatheter. After filling two to three coils, the stent was released (stents used were Neuroform (Boston Scientific, Natick, MA, USA), Enterprise (Cordis), and Solitaire™ AB (Covidien/ev3)). For patients who were scheduled to receive multiple stents, Enterprise stents were preferred. For patients who received destructive surgery, the Echelon10 was delivered to the dissection. For patients without PICA involvement, internal trapping with dense coil packing was performed (Case 1), and for patients with PICA involvement, proximal obliteration was performed (Case 2). After the procedure, aspirin (100mg/d) and Plavix (75mg/d) were administered for six weeks, after which Plavix was withdrawn.
Angiographic follow-ups were scheduled at three to six months, then again at 12 months, and annually thereafter, this extensive follow-up was instigated as it was believed that patients with bilateral dissections may harbor an underlying vasculopathy that may make them more prone for dissections elsewhere. The immediate obliteration grades were categorized as complete obliteration (100%), near-complete obliteration (>90%, including residual dome or base), and partial obliteration (<90%),12,13 which was assessed independently by two authors (JML and WYZ), who have nine and 13 years of neurointerventional experience, respectively. Clinical outcomes were evaluated using the modified Rankin scale score (mRS), and results were classified into favorable outcomes (mRS, 0–1) and unfavorable outcomes (mRS, 2–6)14 on the basis of the most recent follow-up.
The clinical and radiological features of eight VADAs in the four patients are shown in the table. Six VADAs were reconstructed by coiling assisted with a single-stent (n=3), coiling with multiple stents (n=2) and stenting without coils (n=1), while two VADAs were treated by deconstructive techniques with internal trapping or proximal obliteration, respectively. No procedure-related complication occurred.
Complete obliteration was achieved immediately after treatment in three VADs. Near-complete obliteration was achieved in two VADAs immediately after reconstruction with one to three stent(s) and coiling, and transformed to complete obliteration in 20 minutes in Case 4 (Figure 1) and 50 minutes in Case 2 (Figure 2). Partial obliteration was achieved immediately after the procedure in the remaining three VADAs. Patients were followed up by cerebral angiography for a mean of eight (range 6–15) months with complete obliteration in all cases. There was no evidence of thrombosis, in-stent stenosis, or in-stent obliteration. The clinical follow-up period of the four patients averaged 63 (range 43–86) months and all patients had a favorable outcome (mRS 0–1). None of the patients had infarctions in the medulla or territory of the PICA.
Early treatment is recommended for ruptured VADAs, as the re-hemorrhage rate is 30%–71.4% and re-hemorrhage-related mortality is as high as 46.7%.15,16 Whether bilateral vertebral artery dissections fare even worse is, given the small number of reported cases, unclear. Considering the devastating consequence arising from VADA re-rupture, we employed single-stage endovascular treatment for all ruptured intracranial VADAs in this series, and its long-term results were evaluated based on four cases treated in our center over the course of the last 12 years.
Our strategy is to treat both lesions at the same time and employ deconstructive methods in cases we can identify the source of hemorrhage. In cases where we cannot identify the source of hemorrhage, we believe that bilateral reconstructive treatment is the treatment of choice to avoid increasing hemodynamic stress on a potentially untreated recently hemorrhaged lesion. However, this strategy is best within one month after SAH.
We do not think that open surgical intervention is an option for acute dissecting aneurysms of the vertebral artery given its rather high risks of treatment-related morbidity and mortality,3 thus most studies on treatment of these challenging conditions have employed endovascular therapies. Deconstructive endovascular treatments, including proximal obliteration and internal trapping, are established modalities for the treatment of unilateral intracranial VAD17–19 but are limited for bilateral VAD by the degree of posterior communicating artery development.20,21 Deconstructive treatment modalities carry the risks of recurrence, ischemic events and re-bleeding, especially in cases of PICA involvement.22 A unilateral deconstructive treatment in bilateral dissections may furthermore increase expansion and rupture risk of the contralateral VADA, or may lead to the formation of a new dissection resulting from the effect of hemodynamic stress.23,24
Thus, several recent studies proposed reconstructive techniques, both employing stents (with and without additional coiling) and flow-diverting stents8,25,26 as a potential treatment option for intracranial dissecting diseases. The obvious risks associated with these types of treatment are related to the necessity to perform antiaggregation to prevent acute thrombembolic events. In our practice, we load the patients with aspirin and Plavix orally or anally two hours prior to a procedure and we contemplate external ventricular drain (EVD) placement prior to the intervention. The risk of acute re-hemorrhage after stent placement in dissecting aneurysms has been described; however, we believe that by adding coils and/or using multiple stents to increase the strut density over an acute dissection in order to “push the flap back” these events can be minimized.9,10 In addition, using multiple overlapping stents may straighten the curvature of the parent vessel, thus altering hemodynamic forces on the diseased vessel wall.27 Currently, the multiple stents technique is preferred at our center for VADAs; however, in the future, flow-diverting stents28,29 may represent a viable alternative for this type of treatment.
No postoperative re-hemorrhage occurred in our four patients and we demonstrated excellent long-term follow-up results—both from an angiographical and from a clinical point of view.
Nevertheless, a major limitation of this case series is the lack of large numbers. However, we think that our treatment strategy is a valid approach toward the management of these challenging lesions.
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by National Natural Science Foundation of China (grant no. 81271271).
The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.