Abstract
Basilar artery dissection is a rare disease with high morbidity and mortality. No well-established management strategy exists for this lesion. Endovascular reconstructive therapy using stents (with or without coiling) may be the optimum strategy.
We describe our center’s experience for this treatment strategy in 21 patients with basilar artery dissection from January 2009 to July 2014 (17 men, four women; age range, 18–70 years; median age, 56 years). We divided patients into two groups: Group 1 patients received stent-assisted coiling treatment, and Group 2 patients received stent-only treatment. Pre-treatment, peri-operation and follow-up evaluation were investigated for complications, clinical outcome and angiographic results. The median follow-up time was 20 months (range, 3–67 months).
All patients were treated endovascularly by stent-assisted coiling (14 patients) or stent only (seven patients). Immediate angiography showed: in Group 1, five of 14 lesions were completely occluded, five were partially occluded, four revealed retention of contrast media; in Group 2, all patients (seven of seven) had contrast retention. At the follow-up visit (median seven months, 3–29 months), the aneurysms were angiographically improved in five of 13 patients in Group 1 compared with immediately post-operation, while six of sevenimproved in Group 2. Five patients (all in Group 1) had ischemic or hemorrhage peri-operation complications. Long-term good clinical outcomes (modified Rankin Scale score (mRS) ≤ 2) were achieved in all patients except three death cases (two in Group1, one in Group 2).
In our experience, endovascular reconstructive therapy using stents (with or without coiling) for basilar artery dissection is effective and safe. Stent-only treatment seems have a better safety profile during the peri-operation period.
Keywords: Basilar artery dissection, endovascular, stent
Introduction
Spontaneous basilar artery dissection is a rare lesion with a poor prognosis.1 Previous studies showed the death rate to be from 10.0% to 78.9%.2–5 Treatment is empirical; the optimum treatment for this disease is not well established. Although conservative management is recommended by some authors,6 because of high rebleeding risk, especially for ruptured lesions, early intervention by surgery or endovascular treatment is often implemented if feasible.7 While surgery treatment is challenged by technical difficulties,8 more and more reports of endovascular treatment with favorable outcomes have been published in recent years.9–16 And it seemed stent placement (stent-assisted coiling or stent only) had a better outcome compared with coiling only.11 In our center, we used stent placement treatment (with or without coiling) for patients with basilar artery dissection. This paper will report on our experience on 21 consecutive patients with basilar artery dissection treated with stent.
Patients and methods
Patients and general information
Our hospital is an academic tertiary hospital in the region, and many local difficult cases are hospitalized here. Between January 2009 and July 2014, 21 patients with basilar dissecting aneurysms were treated at our center by stent endovascular therapy. Of these patients, there were 17 men and four women. The age range was 18–70 years, with a median age of 56 years. Six patients (28.6%) presented with subarachnoid hemorrhage (SAH), 10 patients (47.6%) with posterior circulation ischemic symptoms, four (19.0%) with cervical pain, and one (4.8%) patient’s condition was found accidentally by angiography with no symptoms. Twelve patients had relatively good condition at baseline (modified Rankin Scale score (mRS) ≤ 2); the remaining nine patients had disability (mRS: 3–5). The baseline characteristics are summarized in Table 1.
Table 1.
Characteristics of patients.
| Characteristics | N (%) |
|---|---|
| Age (median) | 56 |
| Male | 17 (81.0%) |
| Symptoms | |
| Subarachnoid hemorrhage | 6 (28.6%) |
| Ischemic | 10 (47.6%) |
| Cervical pain | 4 (19.0%) |
| Incidental | 1 (4.8%) |
All patients were treated with aspirin (100 mg/d) and clopidogrel (75 mg/d) for at least three days before their operation, except those with SAH. For SAH patients, a loading dose of clopidogrel (400 mg) was used right before the operation and no aspirin was given beforehand. After the endovascular procedure, all patients were maintained on dual antiplatelet therapy (aspirin100 mg/d and clopidogrel 75 mg/d) for 12 weeks and aspirin alone for life.
Management strategy (stent with or without coiling) was determined based on location, size and affected area of the dissection and aneurysm. We divided patients into two groups: Group 1 patients received stent-assisted coiling treatment, and Group 2 patients received stent-only treatment. Basically, if the aneurysm was saccular or had a large diameter (diameter of aneurysm > 2*diameter of reference artery), we put the patient in Group 1. All SAH patients were in Group 1. Endovascular procedure was performed under general anesthesia. Activated coagulation time (ACT) was maintained at two to three times the baseline throughout the procedure. Stent placement or stent-assisted coiling was performed with self-expanding stents (Leo, Balt Extrusion; Solitaire, ev3; Neuroform, Boston Scientific; Enterprise, Codman). Usually, we employed two or three stents for expected hemodynamic improvement. The number of stents placed depended on the angiographic finding of contrast retention. For Group 2 patients, a single stent was placed in one patient; overlapping stents were placed in the remaining six patients:two stents in two patients, three stents in three patients, and four stents in one patient. For Group 1 patients, multiple stents were used to assist coiling occlusion.
Evaluation of outcomes
Pretreatment, peri-operation and follow-up evaluation were investigated for complication, clinical outcome and angiographic results. Patients’ outcomes were evaluated by mRS score. For clinical outcome evaluated by hospital visit or telephone interview, the median follow-up time was 20 months (range, 3–67 months). A follow-up angiography was planned at six months post-operation. The median follow-up time for angiography was seven months (range, 3–19 months). If no contrast retention was found in angiography follow-up, we considered it as angiographically cured.
Results
Anatomical results
Immediate angiography showed: in Group 1, five of 14 lesions were completely occluded, five were partially occluded, and four revealed retention of contrast media. In Group 2, all patients (seven of seven) had contrast retention. All patients had follow-up angiography except one death case immediately after the procedure. At the follow-up visit (median seven months, 3–29 months), the aneurysms were angiographically improved in five of 13 patients in Group 1 compared with immediately post-operation, while there were six of seven in Group 2. Please refer to Table 2.
Table 2.
Angiography results.
| Results | N (%) |
|---|---|
| Right after operation | |
| Group 1 | 14 |
| Complete occlusion | 5 (35.7%) |
| Subtotal occlusion | 5 (35.7%) |
| Contrast retention | 4 (28.6%) |
| Group 2 | 7 |
| Complete occlusion | 0 |
| Subtotal occlusion | 0 |
| Contrast retention | 7 (100%) |
| Total | 21 |
| Complete occlusion | 5 (23.8%) |
| Subtotal occlusion | 5 (23.8%) |
| Contrast retention | 11 (52.4%) |
| Follow-upa | 20 |
| Group 1 | 13 |
| Improveda | 5 (38.5%) |
| Stabilizeda | 7 (53.8%) |
| Worsea | 1 (7.7%) |
| Group 2 | 7 |
| Improveda | 6 (85.7%) |
| Stabilizeda | 0 |
| Worsea | 1 (14.3%) |
| Total | 20 |
| Improveda | 11 (50.5%) |
| Stabilizeda | 7 (35.0%) |
| Worsea | 2 (14.5%) |
Improved, stabilized and worse are all compared with rightafter the operation.
Clinical results and complications
During the peri-operation period (within 30 days after the procedure), five patients had ischemic (three cases) or hemorrhage (two cases) complications in Group 1, while there were none in Group 2. A 57-year-old man with an unruptured aneurysm died in Group 1 rightafter the operation ofacute in-stent thrombosis. A 65-year-old man had bleeding in the cerebellum during the peri-operation time and died ofrebleeding 22 months after procedure.
Long-term good clinical outcomes (mRS ≤ 2) were found in 18/21 (85.7%) patients: 12/14 (85.7%) in Group 1, and six of seven (85.7%) in Group 2. The remaining two patients in Group 1 as mentioned above died. One patient in Group 2 died at 1.5 months afterthe procedure for in-stent thrombosis.
Illustrative cases
Case 1
A 40-year-old man presented with intermittent diplopia and headache for half a year, and left lower limb weakness for half a month. The diagnosis was “brainstem ischemia.” Angiography showed a dissecting aneurysm in the basilar artery. Four overlapping stents were placed. After the procedure, the patient’s symptoms were relieved according to a follow-up visit at three months (Figure 1).
Figure 1.
Case 1. (a) Computed tomography (CT) angiography obtained on admission. (b) Basilar artery angiography at baseline. (a) and (b) The dissecting aneurism (arrow). (c) and (d) ((c) Early in the arteriographic phase; (d) Late in the arteriographic phase) immediately after four overlapping stents were placed; contrast retention can be seen in the aneurysm. (e) Angiogram eight months later, still showing some contrast retention, considered as stabilized.
Case 2
An 18-year-old man presented with headache. Magnetic resonance (MR) angiography showed a dissecting aneurysm in the middle segment of the basilar artery. The endovascular procedure was performed for stent-assisted coiling. We placed two stents and five coils in this case. At six-month follow-up, angiography showed complete occlusion of the aneurysm and a preserved basilar artery. The patient had no headache (Figure 2).
Figure 2.
Case 2. (a) Magnetic resonance (MR) angiography obtained on admission demonstrating double lumen of basilar artery. (b) Basilar artery angiography during the procedure, after placement of five coils and two stents, contrast retention in the aneurysm. (c) and (d) Follow-up angiography exhibited complete occlusion of the aneurysm and parent basilar artery.
Discussion
According to the Third National Survey on the Cause of Death in China, stroke became the first leading death cause in China, responsible for 22.45% of all deaths.17 The number of patients who died from stroke was more than three times that from coronary artery disease, which was different from Western countries.18 Asians also seemed have more intracranial artery dissection, which was an underdiagnosed cause of stroke.19 We found that publications on basilar artery dissection were mostly from Asian populations.1,6,9–13,16,20 It may suggest basilar artery dissection is more challenging for Asians.
The treatment for basilar artery dissection was empirical. Because of its relatively high morbidity and mortality,2–5 we treated this disease aggressively by endovascular therapy. There are two strategy options for endovascular therapy: deconstructive (occlusion or sacrifice of the parent artery) and reconstructive (preserving blood flow through the parent vessel). For basilar artery dissection, the deconstructive way may cause severe neurologic sequelae of unwanted artery occlusion or embolization.11 Only a few cases were reported using this strategy for giant basilar artery aneurysms.12,21 We preferred reconstructive strategy by stent with or without coiling. This strategy can promote thrombosis of the aneurysm and preserveblood flow in the parent artery. Kim et al.16 treated seven acute basilar artery dissection patients with stent placement with or without coiling: Six patients (85.7%) had a favorable outcome (mRS ≤ 2) and one remaining patient died ofrebleeding. In the present study, we had the same rate of favorable outcome: Eighteen out of 21 (85.7%) patients treated with stent-assisted coiling or stent alone had an mRS score ≤2 during follow-up.
How to choose between stent placement with coiling and without coiling was not studied. We found no reported study comparing stent alone and stent with coiling for basilar artery dissection. Some authors believed the combined use of stent placement plus coil embolization can further lower the rebleeding risk compared with stent alone, because it would further lower the impact of blood flow on affected vessels and promote thrombosis in the false lumen.10,11,16 In our present study, we did not find stent-assisted coiling to be superior with respect to long-term outcome; both groups had an 85.7% rate of favorable outcome. Stent-assisted coiling did have a better angiography result. A total of 47.6% patients treated by stent-assisted coiling had a complete or subtotal occlusion of the dissection after procedure, while there were none in the stent-only group. The stent can only reduce the blood flow into the dissection. But for peri-procedure complications, all five complications in this series were in the stent-with-coiling group, while there were none in the stent-alone group. Three of these five patients had ischemic complications of the cerebellum or brainstem. Of the remaining two patients, both died. One patient had a cerebellum hemorrhage and died later of SAH. One died of acute stent thrombosis right after the procedure. We propose the mechanisms of ischemic complications were: 1) embolization from unstable plaque in the dissection; 2) thrombosis caused by multi-stent and coils; 3) occlusion of perforating branches by multiplestents and coils. More complications in the stent-assisted coiling group may suggest the potential harm of coiling by accelerating acute thrombosis in the aneurysm and subsequent embolization of perforating branches and distal arteries. For a large or saccular aneurysm in the basilar artery, we used stent-assisted coiling treatment and found more complications. A flow-diverter stent may be an alternative treatment for these patients; further study is needed to evaluate the efficacy and safety in this particular population.
In this series, two patients died of in-stent thrombosis, although dual-antiplatelet therapy was implied. The response to clopidogrel differs widely from person to person, and about 25% of patients treated with the standard clopidogrel dose exhibit insufficient inhibition of adenosine diphosphate (ADP)-induced platelet aggregation.22 The United States Food and Drug Administration (FDA) in March 2010 issued a black box warning that individuals with low levels of CYP2C19 expression may not get the full effect of clopidogrel. This may also be meaningful for basilar artery dissection patients in whom endovascular therapy with stent would be implemented.
Conclusions
Endovascular reconstructive therapy using stents (stent-assisted coiling or stent only) is effective and safe. Stent-only treatment seems have a better safety profile during the peri-operation period.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
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