Xiaotong Xu

Do patients with basilar or vertebral artery stenosis have a higher stroke incidence poststenting

Background and aim Posterior circulation stenosis may be a risk factor associated with stroke after intracranial stenting as compared with anterior circulation stenosis. Our aim was to test our hypothesis that there was no difference in clinical outcome poststenting between patients with severe stenosis of the basilar artery (BA) and intracranial vertebral artery (VA). Methods Using the Cox proportional hazards regression model adjusted for prespecified factors (qualifying event, and timing of stenting after the qualifying event), we compared primary endpoint (ischemic stroke in the vertebrobasilar territory, including any stroke or death within 30 days of stenting) between patients with severe symptomatic atherosclerotic BA and VA stenosis who underwent elective stenting in our prospective database. Analysis was by intention-to-treat principle. Results Primary endpoint event occurred in 13 (18.8%) of 69 patients with BA stenosis during a mean 23.4 months (9 within 30 days and 4 afterward) and 3 (4.3%) of 70 patients with VA stenosis during a mean 26.4 months (2 within 30 days and 1 afterward). Patients with BA stenosis had a significantly higher risk of the primary endpoint (adjusted HR=4.87, 95% CI 1.37 to 17.29; p=0.014) or any stroke or death within 30 days of stenting (adjusted HR=5.13, 95% CI 1.10 to 23.96; p=0.038) than those with VA stenosis. Conclusion A significantly higher stroke risk poststenting exists in patients with severe BA stenosis than those with VA stenosis. The discrepancy in clinical outcome after stenting between patients with BA and VA stenosis should be considered in clinical practice and stenting trials.

Higher risk of recurrent ischemic events in patients with intracranial in-stent restenosis.

Background and Purpose— Reliable data concerning prognosis of patients with intracranial in-stent restenosis (ISR) is lacking. We prospectively studied long-term outcomes of patients with and without a catheter angiography-verified ISR. Methods— Between September 2001 and May 2009, 540 consecutive patients with symptomatic intracranial atherosclerosis received stenting treatment at our institute. Of them, 226 patients with 233 stented arteries had catheter angiography follow-up after stenting and were enrolled into this study. They were clinically followed up until the end of December 2011. Primary end point was ischemic stroke or transient ischemic attack in the territory of the stented artery after the catheter angiography follow-up. ISR was defined as a catheter angiography-verified stenosis of ≥50% within or immediately adjacent (within range of 3 mm) to the implanted stent. Results— During a mean follow-up of 38.9 months, 27 (11.6%, 27/233) primary end point events were recorded. The risk of primary end point in ISR group was higher compared with non-ISR group (21.1% [12/57] versus 8.5% [15/176]; hazard ratio, 2.94; 95% confidence interval, 1.37–6.30; P=0.005). Multivariable analysis showed that the ISR was an independent risk factor for the primary end point (hazard ratio, 2.79; 95% confidence interval, 1.20–6.49; P=0.017). The median occurrence time of primary end point was 9.9 (interquartile range, 5.0, 21.1) months in ISR group, earlier than that in non-ISR group (26.6 [13.1, 52.9] months; P=0.01). Conclusions— In-stent restenosis after stenting of intracranial atherosclerosis is significantly associated with an increased risk and an earlier occurrence of recurrent ischemic events in the territory of the stented intracranial artery.

Association of thrombelastographic parameters with post-stenting ischemic events

Background and purpose Thrombelastography (TEG) is widely used for the measurement of platelet function. However, few studies have investigated the TEG parameters in patients receiving extracranial or intracranial artery stenting for ischemic cerebrovascular disease. This study sought to describe the association of TEG parameters before the procedure with post-procedural ischemic events after extracranial or intracranial artery stenting. Methods Patients in whom stenting was performed for extracranial or intracranial artery stenosis (70–99%) were recruited into the study. Blood samples were obtained for TEG to assess platelet function before stenting. The primary endpoint was ischemic stroke or transient ischemic attack in the territory of the stented artery. Results A total of 218 patients were included in the study. During a mean follow-up period of 132 days (range 98–226 days), 18 (8.3%) primary endpoint events were recorded. Compared with patients without ischemic events, the ADP-induced platelet-fibrin clot strength (MAADP) was significantly higher (41.57±15.10 vs 33.50±13.86, p=0.020) and the ADP inhibition rate (ADP%) was significantly lower in patients with ischemic events (39.54±23.15 vs 55.29±24.43, p=0.009). Multivariate analysis identified MAADP and ADP% as significant independent predictors of subsequent ischemic events with HRs of 1.036 and 0.965, respectively. From receiver operating characteristic curve analysis, MAADP >49.95 mm had the best predictive value of ischemic events. Conclusions Our study suggests that TEG parameters MAADP and ADP% are associated with subsequent ischemic events in patients with extracranial or intracranial stents. Clinical trial number NCT01925872.

Fractional Flow Assessment for the Evaluation of Intracranial Atherosclerosis: A Feasibility Study

Purpose: Current studies on endovascular intervention for intracranial atherosclerosis select patients based on luminal stenosis. Coronary studies demonstrated that fractional flow measurements assess ischemia better than anatomical stenosis and can guide patient selection for intervention. We similarly postulated that fractional flow can be used to assess ischemic stroke risk. Methods: This was a feasibility study to assess the technical use and safety of applying a pressure guidewire to measure fractional flow across intracranial stenoses. Twenty patients with severe intracranial stenosis were recruited. The percentage of luminal stenosis, distal to proximal pressure ratios (fractional flow) and the fractional flow gradients across the stenosis were measured. Procedural success rate and safety outcomes were documented. Results: All 20 patients had successful crossing of stenosis by the pressure guidewire. Ten patients underwent angioplasty, and 5 had stenting performed. There was one perforator stroke, but not related to the use of the pressure wire. For the 13 patients with complete pre- and postintervention data, the mean preintervention stenosis, fractional flow and translesional pressure gradient were 76.2%, 0.66 and 29.9 mm Hg, whilst the corresponding postintervention measurements were 24.7%, 0.88 and 10.9 mm Hg, respectively. Fractional flow (r = -0.530, p = 0.001) and the translesional pressure gradient (r = 0.501, p = 0.002) only had a modest correlation with the luminal stenosis. Conclusion: Fractional flow measurement by floating a pressure guidewire across the intracranial stenosis was technically feasible and safe in this study. Further studies are needed to validate its use for ischemic stroke risk assessment.

The long term results of vertebral artery ostium stenting in a single center

Background and purpose The long term results of vertebral artery ostium (VAO) stenting remain uncertain. We sought to evaluate the incidence and risk factors for recurrent ischemic events on long term follow-up in patients who have undergone VAO stenting. Methods 190 consecutive patients who had undergone a total of 202 stenting procedures for symptomatic atherosclerotic VAO stenosis between January 2011 and December 2012 were screened. Baseline demographics of the patients and morphological features of VAO were recorded. The primary outcome events analyzed included recurrent transient ischemic attack (TIA), stroke, and vascular related mortality. Risk factors for these recurrent events were identified. Other outcome events analyzed included in-stent restenosis (ISR) ≥50% and stent fracture noted on follow-up. Results Of the 188 patients with available follow-up data (mean follow-up period 16.7 months), 34 patients suffered recurrent TIAs (18.1%); none had stroke or death. 40 patients were found to have ISR (21.2%) and nine patients had stent fracture (4.7%). Patients with recurrent events were significantly more likely to have ISR, stent fracture, vessel tortuosity, and hyperlipidemia than patients without recurrent events. Conclusions Stenting for VAO stenosis seems to be safe and efficacious. The majority of recurrent events were TIAs, which may be related to ISR, stent fracture, vessel tortuosity, and hyperlipidemia.

Selective use of transradial access for endovascular treatment of severe intracranial vertebrobasilar artery stenosis

OBJECTIVE To study the feasibility and safety of transradial artery access for endovascular intervention of severe intracranial vertebrobasilar stenosis for selected patients not suitable for transfemoral access. METHODS This was a retrospective analysis of 58 patients who had undergone intervention for severe intracranial vertebrobasilar stenosis using transradial access between January 2012 and September 2014. The reasons for transradial access were traced. The outcome measures were the technical success rate, 30-day stroke or death in the territory of the culprit artery, periprocedural and access site complication rates. RESULTS Out of the 58 patients, 19 patients (32.8%) used the transradial approach due to poor iliofemoral artery access, 28 (48.3%) due to unfavorable brachiocephalic or subclavian artery anatomy, 11 (19%) due to unfavorable vertebral artery anatomy. The technical success rate was 100%. There were four periprocedural complications, one of which was asymptomatic. The 30-day stroke rate was 5.2% (3/58 patients), with two of them having no residual neurological deficits. There was no mortality. None had access site complications. CONCLUSIONS For selected patients with severe intracranial vertebrobasilar stenosis with difficult femoral access or anatomical variations precluding provision of a stable support for intracranial intervention, the transradial approach was shown to be a safe and feasible alternative route of access. Future trials of endovascular treatment for intracranial posterior circulation strokes should take into account the route of access.

Combined use of stent angioplasty and mechanical thrombectomy for acute tandem internal carotid and middle cerebral artery occlusion.

Purpose Tandem internal carotid and middle cerebral artery occlusion carries a grave prognosis, with intravenous and intra-arterial thrombolytics having low efficacy. Currently, endovascular therapy is a promising means for treatment in which the proximal carotid lesion can be treated with angioplasty and stenting, whilst mechanical thrombectomy can be used for the treatment of the distal occlusion. Two approaches can be used – the antegrade (proximal-to-distal) approach or the retrograde (distal-to-proximal) approach, although there has not yet been any consensus on which is the better approach. Case report We present two patients with tandem occlusions, one treated using the antegrade and one using the retrograde approach, with different revascularization outcomes, despite having similar functional outcome on follow-up. Conclusion The combined use of stent angioplasty and mechanical thrombectomy can be used to treat tandem occlusions, and with procedural modifications, the antegrade approach may more easily achieve technical success.

Performance of computed tomography angiography to determine anterograde and collateral blood flow status in patients with symptomatic middle cerebral artery stenosis

Background The purpose of this study was to determine the performance of computed tomography angiography (CTA) by using a scoring system to predict anterograde and collateral blood flow status in patients with symptomatic middle cerebral artery (MCA) stenosis with use of conventional angiography as standard reference. Methods We retrospectively identified all consecutive patients with unilateral symptomatic MCA stenosis in our center who underwent conventional angiography and CTA within 1 month. The anterograde and collateral blood flow (AnCo) scoring system consisted of anterograde score (AnS) and collateral score (CoS). Evaluation of the CTA images was done independently by two readers, based on the AnCo scoring system. The conventional angiography was assessed by using the Thrombolysis in Cerebral Infarction (TICI) and American Society of Interventional and Therapeutic Neuroradiology (ASITN/SIR) scoring system to determine the status of anterograde and collateral blood flow. Diagnostic performance of AnCo was evaluated by using the area under the receiver operating characteristic (ROC) curve. Results A total of 61 patients were included in the analysis with mean age of 53.4 ± 11.0 years. AnS demonstrated a strong correlation with TICI with statistical significance (r = 0.786; p < 0.001). CoS had a modest yet statistically significant correlation with ASITN/SIR (r = 0.574; p < 0.001). The ROC curve analysis for AnS demonstrated an area under the curve (AUC) of 0.894 (p < 0.001) and the ROC curve analysis for CoS showed an AUC of 0.824 (p < 0.001). Conclusions CTA was a potential method to evaluate anterograde and collateral blood flow status in patients with symptomatic unilateral MCA stenosis.

Visual field impairment predicts recurrent stroke after acute posterior circulation stroke and transient ischemic attack

To evaluate whether visual field impairment (VFI) can predict stroke recurrence in patients with vertebral‐basilar (VB) stroke.

Safety of Low-Dose Aspirin in Endovascular Treatment for Intracranial Atherosclerotic Stenosis

Objectives To evaluate the safety of low-dose aspirin plus clopidogrel versus high-dose aspirin plus clopidogrel in prevention of vascular risk within 90 days of duration of dual antiplatelet therapy in patients treated with intracranial endovascular treatment. Methods From January 2012 to December 2013, this prospective and observational study enrolled 370 patients with symptomatic intracranial atherosclerotic stenosis of ≥70% with poor collateral undergoing intracranial endovascular treatment. Antiplatelet therapy consists of aspirin, at a low-dose of 100 mg or high-dose of 300 mg daily; clopidogrel, at a dose of 75 mg daily for 5 days before endovascular treatment. The dual antiplatelet therapy continued for 90 days after intervention. The study endpoints include acute thrombosis, subacute thrombosis, stroke or death within 90 days after intervention. Results Two hundred and seventy three patients received low-dose aspirin plus clopidogrel and 97 patients received high-dose aspirin plus clopidogrel before intracranial endovascular treatment. Within 90 days after intervention, there were 4 patients (1.5%) with acute thrombosis, 5 patients (1.8%) with subacute thrombosis, 17 patients (6.2%) with stroke, and 2 death (0.7%) in low-dose aspirin group, compared with no patient (0%) with acute thrombosis, 2 patient (2.1%) with subacute thrombosis, 6 patients (6.2%) with stroke, and 2 death (2.1%) in high-dose aspirin group, and there were no significant difference in all study endpoints between two groups. Conclusion Low-dose aspirin plus clopidogrel is comparative in safety with high-dose aspirin plus clopidogrel within 90 days of duration of dual antiplatelet therapy in patients treated with intracranial endovascular treatment.