Abstract
Objectives
The objective of this study was to add more evidence about the efficacy and safety of mechanical thrombectomy in patients with basilar artery occlusion and secondarily to identify prognostic factors.
Methods
Twenty-two consecutive patients (mean age 60.5 years, 15 men) with basilar artery occlusion treated with mechanical thrombectomy were included. Clinical, procedure and radiological data were collected. Primary outcomes were the modified Rankin scale score with a good outcome defined by a modified Rankin scale score of 0–2 and mortality rate at three months.
Results
The median National Institutes of Health stroke scale at admission was 24 (interquartile range 11.5–31.25). Twelve patients (54.5%) required tracheal intubation due to a decreased level of consciousness. Successful recanalisation (modified treatment in cerebral ischaemia scale 2b–3) was achieved in 20 patients (90.9%). A favourable clinical outcome (modified Rankin scale score 0–2) was observed in nine patients (40.9%) and the overall mortality rate was 40.9% (nine patients). Haemorrhagic events were observed in three patients (13.63%). A decreased level of consciousness requiring intubation in the acute setting was more frequent in patients with poor outcomes (84.6%) than in patients with favourable outcomes (11.1%), and in patients who died (100%) compared with those who survived (23.1%), with a statistically significant difference (P = 0.002 and P = 0.001, respectively).
Conclusion
Mechanical thrombectomy is feasible and effective in patients with acute basilar artery occlusion. A decreased level of consciousness requiring tracheal intubation seems to be a prognostic factor and is associated with a poor clinical outcome and higher mortality rate. These initial results must be confirmed by further prospective studies with a larger number of patients.
Keywords: Stroke, basilar artery, endovascular procedures, thrombectomy
Introduction
Basilar artery occlusion (BAO) is a catastrophic variant of stroke with a very low incidence (about 1% of all strokes) but with high rates of death and disability.1,2
Early recanalisation has been proved to be one of the most important predictors of a favourable outcome in patients with posterior circulation stroke.2–6
Previously published studies have shown poor results in these patients when treated conventionally (with antiplatelets, anticoagulation, or both).7 In the past two decades several therapeutic approaches have been used in BAO such as intra-arterial thrombolysis,8 intravenous thrombolysis,9 mechanical thrombectomy10 or bridging therapy (intravenous thrombolysis and mechanical thrombectomy sequentially)11 depending on team experience and resources at each institution, but well-conducted randomised clinical trials are lacking.
Mechanical thrombectomy devices, especially stent retrievers, seem to be effective in vertebrobasilar occlusion treatment in terms of recanalisation.12–14 The low incidence of BAO and different treatment approaches make difficult to determine the efficacy and safety of this technique in this subset of stroke patients. To date, some series of patients with BAO treated by mechanical thrombectomy have been reported in the literature with encouraging results.10,12,15
Without data from randomised trials treatment of BAO using mechanical thrombectomy with stent retrievers should be based in the experience of selected centres. The primary aim of our study was to add more clinical evidence about the efficacy and safety of mechanical thrombectomy in patients with BAO in the acute setting. A secondary objective was to evaluate prognostic factors that could help to identify patients who may benefit from treatment.
Materials and methods
Selection of patients
All consecutive patients with acute BAO confirmed by digital subtraction angiography treated with mechanical thrombectomy within 24 hours from symptom onset, between November 2008 and July 2013, were evaluated in a single-centre study.
Clinical evaluation was performed by a stroke neurologist at admission. Non-enhanced computed tomography (NECT), brain perfusion computed tomography and computed tomography angiography were performed in all patients before treatment. During mechanical thrombectomy patients were awake or under general anaesthesia depending on clinical circumstances. Oxygenation and strict blood pressure control was maintained during the procedure in all cases. A 24-hour follow-up NECT was always performed to rule out haemorrhagic complications.
Indications for mechanical thrombectomy were the presence of BAO associated with a severe neurological deficit defined as a National Institutes of Health stroke scale (NIHSS) > 6 and previous modified Rankin scale (mRS) score ≤ 2. Contraindications for the procedure were haemorrhage or evidence of extended brainstem infarction on baseline NECT, symptom onset > 24 hours, the absence of vascular occlusion on computed tomography angiography or the presence of terminal illness.
All patients (or relatives) signed informed consent forms before treatment. The study was approved by the ethics committee.
Clinical data
Clinical data including age, sex, cardiovascular risk factors such as hypertension, diabetes, atrial fibrillation, smoking or dyslipidaemia, stroke aetiology according to the trial of Org 10172 in acute stroke treatment (TOAST) classification,16 baseline NIHSS and Glasgow coma scale (GCS) scores at admission were collected.
Clinical outcome (mRS) score and mortality rates at 90 days were obtained from the medical records data, which are collected by a stroke neurologist. Favourable outcome was defined as mRS ≤ 2.
Procedure data
Information about use of bridging therapy, time to treatment (time from symptom onset to groin puncture), procedure duration (time from needle puncture to recanalisation), time to recanalisation (time from symptom onset to recanalisation), devices used in each case (Solitaire; Covidien, Dublin, Ireland; Trevo; Stryker, Mountain View, CA, USA; or MERCI; Stryker, Mountain View), intra-arterial stent placement and endovascular treatment-related complications (vessel perforation or arterial dissection) were recorded as procedure information. General anaesthesia requirements were also assessed.
Regarding the technique, most of the procedures were performed with a 6F guide catheter in the dominant vertebral artery without intermediate catheter. Then we crossed the thrombus with a microcatheter (Trevo Pro 18 MC; Stryker, Kalamazoo, MI, USA) and a micro guidewire Synchro 14 (Stryker, Kalamazoo). Thrombectomy was performed in most of the cases with a stent retriever device like the Trevo device (Stryker, Kalamazoo) or Solitaire device (Covidien, Dublin, Ireland). When a stent was required, antiplatelet therapy with intravenous aspirin was used in the acute phase in the angio suite. If in the follow-up imaging there was no haemorrhagic complications, the patient was started on dual antiplatelet therapy with aspirin and clopidogrel for three months.
Radiological data
Two neuroradiologists (one with more than 10 years of experience and another with 5 years of experience) blinded to clinical information, assessed recanalisation rates in consensus using the modified treatment in cerebral ischaemia scale (mTICI)17 on digital subtraction angiography. Successful recanalisation was defined as a mTICI score of 2b–3. The sites of occlusion were also assessed dividing the basilar artery (BA) into three segments, proximal BA (from the vertebral artery junction to the origins of the anteroinferior cerebellar artery), middle BA (from the anteroinferior cerebellar artery to the origins of the superior cerebellar artery) and distal BA (above the origins of the superior cerebellar artery).
Haemorrhagic events were classified according to clinical and post-procedure NECT criteria. Haemorrhagic infarction and parenchymal haemorrhage as defined in the European Cooperative Acute Stroke Study classification,18 subarachnoid haemorrhage (SAH) and symptomatic haemorrhage were recorded. Symptomatic intracranial haemorrhage was defined as the presence of blood on NECT associated with clinical deterioration or a decline of four points in the NIHSS score. Procedure-related complications such as arterial perforation, defined as angiographic contrast extravasation that occurred during the procedure, or arterial dissection described as the presence of an intimal flap on the control angiogram obtained after thrombectomy were also documented.
Statistical analysis
Descriptive analysis included frequencies and percentages for categorical variables and mean (standard deviation; SD) or median (interquartile range; IQR) for continuous variables. The patients were classified into two groups according to clinical outcome (favourable/poor) and into another two groups determined by mortality. Univariate analysis was done using the Mann–Whitney U test for continuous variables and the χ2 test or Fisher exact test for categorical variables. Statistical analyses were performed using the Statistical Package for the Social Sciences software, version 20.0 (SPSS, Chicago, IL, USA). A P value less than 0.05 was considered significant.
Results
Population data and descriptive analysis
Between November 2008 and July 2013, 28 consecutive patients with vertebrobasilar stroke were admitted to endovascular treatment in our centre. Six patients were excluded from the analysis because they had posterior cerebral artery occlusion (four patients were excluded because in angiography they showed occlusion of P2 or distal occlusion of the posterior cerebral artery) or BAO treated with intra-arterial fibrinolysis (two patients). Finally, 22 patients with BAO treated with mechanical thrombectomy were chosen for the analysis and were included in our study.
Patient characteristics and procedure information are summarised in Tables 1 and 2.
Table 1.
Patient characteristics.
| n (%) | |
|---|---|
| Age, years (median; IQR) | 60.5 (50–75) |
| Gender; male | 15 (68.2) |
| NIHSS (median; IQR) | 24 (11.5–31.25) |
| Risk factors | |
| Hypertension | 14 (63.6) |
| Diabetes | 5 (22.7) |
| Atrial fibrillation | 6 (27.3) |
| Smoke | 4 (18.2) |
| Dyslipidaemia | 11 (50) |
| Presumed aetiology (TOAST) | |
| Large artery atherosclerosis | 5 (21.7) |
| Cardioembolism | 9 (39.1) |
| Small vessel occlusion | – |
| Stroke of other determined aetiology | 2 (8.7) |
| Stroke of undetermined aetiology | 6 (26.1) |
| Anaesthesia requirements | |
| No sedation (awake) | 10 (45.5) |
| Sedation (spontaneous ventilation) | 0 (0) |
| General anaesthesia (assisted ventilation) | 12 (54.5) |
| Reasons for anaesthesia and tracheal intubation | |
| Uncooperative patient | 0 (0) |
| GCS score < 8 | 12 (54.5) |
| Respiratory failure | 0 (0) |
IQR: interquartile range; NIHSS: National Institutes of Health stroke score; TOAST: trial of org 10172 in acute stroke treatment; GCS: Glasgow coma score.
Table 2.
Procedure information.
| n (%) | |
|---|---|
| Bridging therapy with IV-rtPA | 4 (18.2) |
| Time from symptom onset to groin puncture in minutes (median; IQR) | 257 (130.75–412.5) |
| Procedural time in minutes (median; IQR) | 79.5 (43.75–112.5) |
| Time to recanalisation median (IQR) | 329.5 (213.75–518.75) |
| Intra-arterial stenting | |
| Intracraneal (V4–basilar) | 3 (13.6) |
| Extracraneal (V1–V3) | 4 (18.2) |
| Post-procedure mTICI score | |
| I–IIa | 2 (9.1) |
| IIb–III | 20 (90.9) |
| Devices | |
| Trevo | 15 (68.18) |
| Merci | 3 (13.63) |
| Solitaire | 1 (4.54) |
| Trevo + Merci/Solitaire | 3 (13.63) |
IQR: interquartile range; IV-rtPA: intravenous recombinant tissue plasminogen activator; mTICI: modified treatment in cerebral ischaemia scale.
The mean age was 60.5 years and 15 patients were men. The baseline NIHSS score was not available in eight patients on medical records because they had to be intubated before data could be collected. The median NIHSS score at admission of the other 14 patients was 24 (IQR 11.5–31.25). Twelve patients (54.5%) required tracheal intubation in the acute phase prior to or during the procedure due to a decreased level of consciousness. The reasons for anaesthesia and tracheal intubation are listed in Table 1.
On digital subtraction angiography, all patients showed complete occlusion (mTICI 0) of the BA before treatment. The site of occlusion was the proximal segment of the BA in seven cases (31.82%), the middle BA in four cases (18.18%) and the distal BA in 11 patients (50%).
At the end of the procedure, successful recanalisation (mTICI 2b–3) was achieved in 20 patients (90.9%). Recanalisation was not possible in two patients (9.1%), resulting in one patient with a mTICI 1 and another with a mTICI 2a. These two patients died within 48 hours from symptom onset. In those patients, recanalisation was not possible probably because of a local problem in the BA (atherosclerotic stenosis, plaque rupture, etc.). A stent was deployed in seven patients in order to open the underlying stenosis, four patients at the origin of the vertebral artery and the other three patients at the vertebrobasilar junction.
A favourable clinical outcome (mRS score 0–2) at three months was observed in nine patients (40.9%) and the overall mortality rate was 40.9% (nine patients). The remaining four patients had a mRS score of 3 in two cases, a mRS score of 4 in one patient and a mRS score of 5 in another patient.
Regarding endovascular treatment-related complications, no arterial perforations or arterial dissections were detected. Haemorrhagic events were observed in three patients (13.63%) after the procedure. Two of them (9.09%) were haemorrhagic infarcts (HI2) and one patient (4.54%) had a focal SAH. No patient had a parenchyma haematoma or symptomatic cerebral haemorrhage as a complication of the procedure.
Predictive factors for clinical outcome
In this study we did not find any significant statistical difference between groups (functional outcome and mortality) in terms of age, sex and cardiovascular risk factors (Tables 3 and 4).
Table 3.
Initial clinical and treatment characteristics of patients according to outcome.
| Favourable outcome (mRS ≤ 2) |
Poor outcome (mRS > 2) |
P value | |||
|---|---|---|---|---|---|
| n | Value | N | Value | ||
| Age, median (IQR) | 9 | 62 (47.5–79.5) | 13 | 56 (50–73.5) | 0.442 |
| Male gender | 5 | 55.6% | 10 | 76.9% | 0.301 |
| Hypertension | 5 | 55.6% | 9 | 69.2% | 0.756 |
| Diabetes | 1 | 11.1% | 4 | 30.8% | 0.352 |
| Atrial fibrillation | 3 | 33.3% | 3 | 23.1% | 0.488 |
| Smoke | 2 | 22.2% | 2 | 15.4% | 0.595 |
| Dyslipidaemia | 3 | 33.3% | 8 | 61.5% | 0.296 |
| Admission NIHSS score, median (IQR) | 5 | 12 (5.5–28.5) | 9 | 26 (16–31.5) | 0.162 |
| IV-rtPA | 3 | 33.3% | 1 | 7.7% | 0.134 |
| Decreased level of consciousness requiring tracheal intubation | 1 | 11.1% | 11 | 84.6% | 0.002 |
| Time to treatment, median (IQR) | 9 | 311 (187.5–496) | 13 | 210 (125–420) | 0.333 |
| Procedure time, median (IQR) | 9 | 57 (37.5–102) | 13 | 96 (52–124) | 0.229 |
| Time to recanalisation, median (IQR) | 9 | 358 (225–558.5) | 13 | 291 (200–542.5) | 0.526 |
| Successful recanalisation, (mTICI 2b/3) | 9 | 100% | 11 | 84.6% | 0.228 |
IV-rtPA: intravenous recombinant tissue plasminogen activator; mTICI: modified treatment in cerebral ischaemia scale; mRS, modified Rankin scale; IQR: interquartile range.
Table 4.
Initial clinical and treatment characteristics of patients according to mortality.
| Mortality NO |
Mortality YES |
P value | |||
|---|---|---|---|---|---|
| n | Value | n | Value | ||
| Age, median (IQR) | 13 | 62 (44.5–79.5) | 9 | 56 (52–69.5) | 0.525 |
| Male, gender | 8 | 61.5% | 7 | 77.8% | 0.432 |
| Hypertension | 8 | 61.5% | 6 | 66.7% | 1.000 |
| Diabetes | 3 | 23.1% | 2 | 22.2% | 0.885 |
| Atrial fibrillation | 4 | 30.8% | 2 | 22.2% | 0.586 |
| Smoke | 3 | 23.1% | 1 | 11.1% | 0.434 |
| Dyslipidaemia | 5 | 38.5% | 6 | 66.7% | 0.268 |
| Admission NIHSS score, median (IQR) | 8 | 20 (9–29.5) | 6 | 27.5 (13.75–34.5) | 0.302 |
| IV-rtPA | 3 | 23.1% | 1 | 11.1% | 0.485 |
| Decreased level of consciousness requiring tracheal intubation | 3 | 23.1% | 9 | 100% | 0.001 |
| Time to treatment, median (IQR) | 13 | 297 (187.5–496) | 9 | 195 (125–420) | 0.367 |
| Procedure time, median (IQR) | 13 | 57 (38–113) | 9 | 96 (69–122.5) | 0.256 |
| Time to recanalisation, median (IQR) | 13 | 358 (225–558.5) | 9 | 290 (172.5–542.5) | 0.367 |
| Successful recanalisation, (mTICI 2b/3) | 13 | 100% | 7 | 77.8% | 0.082 |
IV-rtPA: intravenous recombinant tissue plasminogen activator; mTICI: modified treatment in cerebral ischaemia scale; mRS: modified Rankin scale; IQR: interquartile range.
Regarding clinical severity at admission, the median (IQR) NIHSS score was 12 (5.5–28.5) in those patients with favourable outcomes and 26 (16–31.5) in those with poor outcomes, showing a non-significant trend towards a higher good outcome rate (P = 0.162) in those patients with lower admission NIHSS scores.
According to treatment modality, patients with bridging therapy showed a non-significant trend towards a higher favourable outcome rate compared with patients who were treated with mechanical thrombectomy alone (33.3% vs. 7.7%; P = 0.134). No time measures (time to treatment, procedure time or time to recanalisation) were associated with better outcomes or a lower mortality rate.
Concerning the reasons for anaesthesia and tracheal intubation, 12 patients required intubation in the acute setting because of a decreased level of consciousness in our series. Of these 12 patients, nine of them died (75%) and only one was functionally independent (8.33%) at three months follow-up. In univariate analysis, a decreased level of consciousness requiring intubation in the acute setting was more frequent in patients with poor outcomes (84.6%) than in patients with favourable outcomes (11.1%), and in patients who died (100%) compared with those who survived (23.1%), with a statistically significant difference (P = 0.002 and P = 0.001, respectively).
High recanalisation rates (90.9%) were achieved. Recanalisation was achieved in all patients who survived (13 patients, 100%) and in 77.8% of patients who died (seven patients) showing a non-significant trend (P = 0.082). It is important to note that those two patients in whom recanalisation was not possible died. A similar finding was observed in clinical outcome analysis; recanalisation was achieved in all nine patients (100%) who had a favourable outcome while recanalisation was achieved in 84.6% of patients with poor outcomes (11 patients), again with a non-significant difference (P = 0.228). No other factors related to clinical outcome or mortality rate were found in our analysis (Tables 3 and 4).
Discussion
In our study we obtained high recanalisation rates (90.9%) in patients with BAO treated with mechanical thrombectomy. We observed that nine of our patients (40.9%) were functionally independent at three months, with an overall mortality of 40.9%.
These results are comparable to those of other series published to date of patients with BAO treated with mechanical thrombectomy or a multimodal approach in terms of successful recanalisation, favourable outcome and mortality rates (Table 5). Recanalisation rates ranged from 64% to 100% with higher rates in studies performed with stent retrievers exclusively. Regarding good functional outcome and mortality rate, results ranged from 22.2% to 57% and 12% to 59.2%, respectively.10–12,14,15,19–23 Singer et al.23 recently achieved successful recanalisation in 111 patients out of a total of 141 (79%) in the largest series of BAO with endovascular treatment published until now as part of the ENDOSTROKE study, and reported good clinical outcomes in 34% of patients, with a mortality rate of 35%. In general, the endovascular approach achieves higher recanalisation rates than conventional treatment,7 intra-arterial thrombolysis8 or intravenous thrombolysis.9
Table 5.
BAO endovascular mechanical series.
| Patients (n) | Successful recanalisation (%) | Favourable outcome (mRS 0–2) (%) | Symptomatic intracranial haemorrhage (%) | Mortality rate (%) | |
|---|---|---|---|---|---|
| Lutsep et al.20 | 27 | 78 | 33 | 19 | 44 |
| Pfefferkorn et al.11 | 26 | 85 | 38 | 8 | 31 |
| Mourand et al.19 | 31 | 74 | 35 | 16 | 32 |
| Mordasini et al.14 | 14 | 100 | 28.6 | 0 | 35.7 |
| Espinosa et al.12 | 18 | 94.4 | 50 | 0 | 22.2 |
| Andersson et al.10 | 28 | 64 | 57 | 0 | 21 |
| Costalat et al.15 | 16 | 81 | 44 | 6.25 | 25 |
| Delgado et al.22 | 27 | 85.1 | 22.2 | 3.7 | 59.2 |
| Singer et al.23 | 148 | 79 | 34 | 5.4 | 35 |
| Baek et al.21 | 25 | 96 | 48 | 0 | 12 |
| Our series | 22 | 90.9 | 40.9 | 0 | 40.9 |
BAO: basilar artery occlusion; mRS: modified Rankin scale.
In terms of safety, no treatment-related complications such as arterial perforation or arterial dissection were identified in our study. Haemorrhagic events were observed in three patients (13.63%), two haemorrhagic infarcts (HI2) and one focal SAH. None of these events were symptomatic. These low rates of complications are similar to those published in previous studies. In a series published by Costalat et al.15 one patient developed a symptomatic parenchymal haematoma (PH2) out of a total of 16 patients (6.25%) treated with combined therapy. Mourand et al.19 reported one vertebral artery dissection with infarction of the posterior inferior cerebellar artery (PICA) territory and no arterial perforation in any patient. Delgado et al.22 described four haemorrhagic transformations in their series of 27 patients with BAO (14.8%), three parenchymal haematomas (11.1%) and one haemorrhagic infarct (3.7%). One patient with parenchymal haematoma was considered symptomatic because of the presence of a mass effect. Singer et al.23 reported nine intracranial haemorrhagic complications (eight symptomatic) in a multicentre study with 148 patients (6%), two SAH, five intracranial haemorrhages (three parenchymal hematoma (PH), two hemorrhagic infarction (HI)) and two SAH with intracranial haemorrhage. The authors found an association between the combination of intravenous and intra-arterial thrombolysis and mechanical recanalisation, with a higher haemorrhage rate than other treatment options. This association was not present in our study maybe due to the small size of our sample.
Numerous prognostic factors have been identified in patients with BAO that could have influenced the prognosis of the patient.2–5,24 Recanalisation of the BA is one of the most important prognosis factors. In a recent meta-analysis, Kumar et al.25 demonstrated that recanalisation in BAO is associated with a twofold reduction in mortality and a 1.5-fold reduction in death or dependency. In our study, we did not find a statistical association between recanalisation rates and good functional outcomes. Endovascular treatment of patients in a poor clinical situation may have contributed to the lack of this association. These results agree with the findings of other studies of mechanical thrombectomy,10,19,23 in which recanalisation rates did not correlate with the functional outcome of patients with BAO.
As mentioned previously, high recanalisation rates were achieved in patients with BAO treated with mechanical thrombectomy, but no correlation with clinical outcomes was found. Stent retrievers provide high recanalisation rates, other factors should be identified in order to select those patients more likely to benefit from endovascular treatment. Prior studies have noted the importance of clinical severity at admission. In our study population, the baseline NIHSS scores showed no statistically significant association with clinical outcomes. Lack of baseline NIHSS data (eight patients were referred to our centre already intubated before the NIHSS score was recorded) could be the reason for the absence of these associations in our series, and is an important limitation in order to analyse these data. It is interesting to note that the NIHSS was developed for anterior circulation strokes, so it is therefore not really suitable for BAO. In a recently published multicentre registry23 of patients with BAO undergoing endovascular treatment, the initial NIHSS score is an independent risk factor for the clinical outcome, median NIHSS scores were lower in patients with good outcomes (9 (5–17)) compared with those with poor outcomes (24 (15–30)) (P = 0.001).
Jung et al.,3 in a series of 106 patients with BAO treated with intra-arterial thrombolysis, found an association between lower admission NIHSS scores and good and moderate clinical outcomes (mRS 0–3) (P < 0.0001). These findings are consistent with those of Baek and colleagues,21 who recently published a series of 25 patients with BAO treated with mechanical thrombectomy within 8 hours of symptom onset. They found that the median NIHSS score at admission was significantly lower in patients with good clinical outcomes (mRS 0–2) compared to those with poor clinical outcomes (9.5 vs. 14; P = 0.005). These three studies did not take into account the GCS score or comatose status at the time of onset.
It is interesting to note that in the current study, the baseline clinical score (GCS or NIHSS) was not recorded in all patients; however, we assume that a decreased level of consciousness requiring tracheal intubation is an indirect sign of a bad clinical situation. A decreased level of consciousness requiring intubation was associated with poor outcomes (11.1% vs. 84.6%, P = 0.002) and higher mortality rates (23.1% vs. 100%, P = 0.001). Twelve patients required tracheal intubation because the GCS score dropped below 8. Nine (75%) of these 12 patients died during admission and only one patient had a good clinical outcome at three months follow-up.
In contrast to our findings, some previous studies did not show statistically significant associations between clinical outcome and the GCS score on admission. Andersson et al.10 treated 14 patients with GCS scores ≤ 8 and they obtained a good clinical outcome in seven patients (50%). Mourand et al.19 treated 19 patients in comatose status and six patients achieved a good clinical outcome at three months. Otherwise, Chandra et al.26 analysed 16 patients with GCS scores ≤ 6 obtaining a good functional outcome in six patients. All these series have been unable to show statistically significant associations between the GCS score on admission and clinical outcome.
On the other hand, Schulte-Altedorneburg et al.5 demonstrated associations between the coma duration and clinical outcome. In this study, none of the 10 patients with more than 8.5 hours of coma obtained a good clinical outcome. Ten percent of patients with 4.5–8 hours of coma duration obtained good clinical outcomes, and the good clinical outcome rate was 22% in those patients with less than 4 hours of coma. Duration of the coma was not recorded in our study or in other mechanical thrombectomy series in acute BAO. We hypothesise that, in posterior circulation stroke, coma duration could be more important in terms of prognosis than time from clinical onset. Recently, Lindsberg et al.27 highlighted a better functional prognosis regarding the clinical presentation in which fluctuating symptoms seem to be a positive sign in contrast to uninterrupted coma. So further research should be undertaken to investigate the association between clinical presentation, coma duration and the clinical outcome of patients with acute BAO.
The main limitations in our study are its retrospective design with a small sample size and the loss of clinical information that could be important to the assessment of prognosis factors. Otherwise, the present study provides more evidence about the safety and efficacy of mechanical thrombectomy in acute BAO, showing that the requirement of tracheal intubation may be a prognostic factor of a poor outcome.
Conclusions
Mechanical thrombectomy is feasible and effective in patients with acute BAO. A decreased level of consciousness requiring tracheal intubation seems to be a prognostic factor and is associated with poor clinical outcomes and higher mortality rates. These initial results must be confirmed by further prospective studies with a larger number of patients.
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.
References
- 1.Schonewille WJ, Wijman CA, Michel P, et al. Treatment and outcomes of acute basilar artery occlusion in the Basilar Artery International Cooperation Study (BASICS): a prospective registry study. Lancet Neurol 2009; 8(8): 724–730. PubMed PMID: 19577962. [DOI] [PubMed] [Google Scholar]
- 2.Mattle HP, Arnold M, Lindsberg PJ, et al. Basilar artery occlusion. Lancet Neurol 2011; 10(11): 1002–20014. [DOI] [PubMed] [Google Scholar]
- 3.Jung S, Mono ML, Fischer U, et al. Three-month and long-term outcomes and their predictors in acute basilar artery occlusion treated with intra-arterial thrombolysis. Stroke; a journal of cerebral circulation 2011; 42(7): 1946–1951. [DOI] [PubMed] [Google Scholar]
- 4.Sairanen T, Strbian D, Soinne L, et al. Intravenous thrombolysis of basilar artery occlusion: predictors of recanalization and outcome. Stroke; a journal of cerebral circulation 2011; 42(8): 2175–2179. [DOI] [PubMed] [Google Scholar]
- 5.Schulte-Altedorneburg G, Hamann GF, Mull M, et al. Outcome of acute vertebrobasilar occlusions treated with intra-arterial fibrinolysis in 180 patients. AJNR Am J Neuroradiol 2006; 27(10): 2042–2047. [PMC free article] [PubMed] [Google Scholar]
- 6.Lindsberg PJ, Mattle HP. Therapy of basilar artery occlusion: a systematic analysis comparing intra-arterial and intravenous thrombolysis. Stroke; a journal of cerebral circulation 2006; 37(3): 922–928. [DOI] [PubMed] [Google Scholar]
- 7.Schonewille WJ, Algra A, Serena J, et al. Outcome in patients with basilar artery occlusion treated conventionally. J Neurol, Neurosurg, Psychiatry 2005; 76(9): 1238–12341. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Hacke W, Zeumer H, Ferbert A, et al. Intra-arterial thrombolytic therapy improves outcome in patients with acute vertebrobasilar occlusive disease. Stroke; a journal of cerebral circulation 1988; 19(10): 1216–1222. [DOI] [PubMed] [Google Scholar]
- 9.Lindsberg PJ, Soinne L, Tatlisumak T, et al. Long-term outcome after intravenous thrombolysis of basilar artery occlusion. JAMA: The journal of the American Medical Association 2004; 292(15): 1862–1866. [DOI] [PubMed] [Google Scholar]
- 10.Andersson T, Kuntze Soderqvist A, Soderman M, et al. Mechanical thrombectomy as the primary treatment for acute basilar artery occlusion: experience from 5 years of practice. J Neurointervent Surg 2013; 5(3): 221–2235. [DOI] [PubMed] [Google Scholar]
- 11.Pfefferkorn T, Holtmannspotter M, Schmidt C, et al. Drip, ship, and retrieve: cooperative recanalization therapy in acute basilar artery occlusion. Stroke; a journal of cerebral circulation 2010; 41(4): 722–726. [DOI] [PubMed] [Google Scholar]
- 12.Espinosa de Rueda M, Parrilla G, Zamarro J, et al. Treatment of acute vertebrobasilar occlusion using thrombectomy with stent retrievers: initial experience with 18 patients. AJNR Am J Neuroradiol 2013; 34(5): 1044–1048. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Mortimer AM, Bradley M, Renowden SA. Endovascular therapy for acute basilar artery occlusion: a review of the literature. J Neurointervent Surg 2012; 4(4): 266–273. [DOI] [PubMed] [Google Scholar]
- 14.Mordasini P, Brekenfeld C, Byrne JV, et al. Technical feasibility and application of mechanical thrombectomy with the Solitaire FR Revascularization Device in acute basilar artery occlusion. AJNR Am J Neuroradiol 2013; 34(1): 159–163. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Costalat V, Machi P, Lobotesis K, et al. Rescue, combined, and stand-alone thrombectomy in the management of large vessel occlusion stroke using the solitaire device: a prospective 50-patient single-center study: timing, safety, and efficacy. Stroke; a journal of cerebral circulation 2011; 42(7): 1929–1235. [DOI] [PubMed] [Google Scholar]
- 16.Adams HP, Jr, Bendixen BH, Kappelle LJ, et al. Classification of subtype of acute ischemic stroke. Definitions for use in a multicenter clinical trial. TOAST. Trial of Org 10172 in Acute Stroke Treatment. Stroke; a journal of cerebral circulation 1993; 24(1): 35–41. [DOI] [PubMed] [Google Scholar]
- 17.Zaidat OO, Yoo AJ, Khatri P, et al. Recommendations on angiographic revascularization grading standards for acute ischemic stroke: a consensus statement. Stroke; a journal of cerebral circulation 2013; 44(9): 2650–2663. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Trouillas P, von Kummer R. Classification and pathogenesis of cerebral hemorrhages after thrombolysis in ischemic stroke. Stroke; a journal of cerebral circulation 2006; 37(2): 556–561. [DOI] [PubMed] [Google Scholar]
- 19.Mourand I, Machi P, Milhaud D, et al. Mechanical thrombectomy with the Solitaire device in acute basilar artery occlusion. J Neurointervent Surg 2014; 6(3): 200–204. [DOI] [PubMed] [Google Scholar]
- 20.Lutsep HL, Rymer MM, Nesbit GM. Vertebrobasilar revascularization rates and outcomes in the MERCI and multi-MERCI trials. Journal of Stroke and Cerebrovascular Diseases: The official journal of National Stroke Association 2008; 17(2): 55–57. [DOI] [PubMed] [Google Scholar]
- 21.Baek JM, Yoon W, Kim SK, et al. Acute basilar artery occlusion: outcome of mechanical thrombectomy with Solitaire stent within 8 hours of stroke onset. AJNR Am J Neuroradiol 2014; 35(5): 989–993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Delgado Acosta F, Jimenez Gomez E, de Asis Bravo Rodriguez F, et al. [Vertebrobasilar recanalization techniques before the placement of stent-retrievers: reopening is not synonymous with good outcome]. Radiologia 2014; 56(1): 44–51. [DOI] [PubMed] [Google Scholar]
- 23.Singer OC, Berkefeld J, Nolte CH, et al. Mechanical recanalization in basilar artery occlusion: the ENDOSTROKE study. Ann Neurol 2015; 77(3): 415–424. [DOI] [PubMed] [Google Scholar]
- 24.Arnold M, Nedeltchev K, Schroth G, et al. Clinical and radiological predictors of recanalisation and outcome of 40 patients with acute basilar artery occlusion treated with intra-arterial thrombolysis. J Neurol, Neurosurg, Psychiatry 2004; 75(6): 857–862. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Kumar G, Shahripour RB, Alexandrov AV. Recanalization of acute basilar artery occlusion improves outcomes: a meta-analysis. J Neurointervent Surg 2015; 7(12): 868–874. [DOI] [PubMed] [Google Scholar]
- 26.Chandra RV, Law CP, Yan B, et al. Glasgow coma scale does not predict outcome post-intra-arterial treatment for basilar artery thrombosis. AJNR Am J Neuroradiol 2011; 32(3): 576–580. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Lindsberg PJ, Pekkola J, Strbian D, et al. Time window for recanalization in basilar artery occlusion: speculative synthesis. Neurology 2015; 85(20): 1806–1815. [DOI] [PubMed] [Google Scholar]