Ligang Song

Outcomes of tailored angioplasty and/or stenting for symptomatic intracranial atherosclerosis: a prospective cohort study after SAMMPRIS

Background and purpose High periprocedural complication rate is a key limitation of endovascular treatment of intracranial atherosclerotic disease (ICAD), despite potential risk reduction of recurrent stroke. Taking lessons from the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Arterial Stenosis (SAMMPRIS) trial, targeting a selected patient population, we prospectively evaluated the feasibility and safety of tailored angioplasty and/or stenting for patients with ICAD. Methods From November 2011 to October 2012, 158 patients with symptomatic ICAD caused by hypoperfusion combined with poor collateral flow were consecutively recruited into a prospective single center study. Patients were divided into three groups based on arterial access and lesion morphology: balloon mounted stent group (group BS) for smooth access and Mori A lesion, angioplasty plus self-expanding stent group (group AS) for tortuous access and Mori B or C lesion, and angioplasty group (group AG) for tortuous access and Mori A lesion. The primary endpoints were successful procedure rate and any vascular event within 30 days. Results Overall technical success rate was 96.3% (154/158). There were significant differences in the technical success rate: 89.7% (35/39) in group AG compared with 97.5% (79/81) in group BS and 100% (38/38) in group AS (p=0.042). The 30 day composite stroke, myocardial infarction, or death rate was 4.4% (7/158). Stroke within 30 days occurred in four patients in group BS and in three patients in group AS. Conclusions Individualized treatment of ICAD using tailored devices according to arterial access and lesion morphology was feasible and safe in symptomatic patients caused by hypoperfusion with poor collateral flow.

Association of PON1, P2Y12 and COX1 with Recurrent Ischemic Events in Patients with Extracranial or Intracranial Stenting

Background and Purpose Short-term combined use of clopidogrel and aspirin improves cerebrovascular outcomes in patients with symptomatic extracranial or intracranial stenosis. Antiplatelet non-responsiveness is related to recurrent ischemic events, but the culprit genetic variants responsible for the non-responsiveness have not been well studied. We aimed to identify the genetic variants associated with poor clinical outcomes. Methods Patients with symptomatic extracranial or intracranial stenosis scheduled for stenting and receiving dual antiplatelets (clopidogrel 75 mg and aspirin 100 mg daily) for at least 5 days before intervention were enrolled. Ischemic events including recurrent transient ischemic attack, stroke, myocardial infarction, and vascular-related mortality within 12 months follow-up were recorded. We examined the influence of genetic polymorphisms on treatment outcome in our patients. Results A total of 268 patients were enrolled into our study and ischemic events were observed in 39 patients. For rs662 of paraoxonase 1 (PON1), allele C was associated with an increased risk of ischemic events (OR = 1.64, 95%CI = 1.03–2.62, P = 0.029). The A-allele carriers of rs2046934 of P2Y12 had a significant association with adverse events (OR = 2.01, 95%CI = 1.10–3.67, P = 0.041). The variant T-allele of cyclooxygenase-1 (COX1) rs1330344 significantly increased the risk of recurrent clinical events (OR = 1.85, 95%CI = 1.12–3.03, P = 0.017). The other single nucleotide polymorphism (SNP) had no association with ischemic events. Conclusions PON1, P2Y12 and COX1 polymorphisms were associated with poorer vascular outcomes. Testing for these polymorphisms may be valuable in the identification of patients at risk for recurrent ischemic events.

Endovascular Mechanical Thrombectomy with the Solitaire Device for the Treatment of Acute Basilar Artery Occlusion

OBJECTIVE To determine the safety and efficacy of endovascular treatment with the Solitaire device for acute basilar artery occlusion (ABAO) and identify factors affecting clinical outcomes. METHODS We enrolled 36 consecutive ABAO patients (aged 58.6 ± 8.10 years) who underwent mechanical thrombectomy with the Solitaire device. We analyzed baseline characteristics, mechanical thrombectomy results, and factors predicting clinical outcomes, which were assessed at 90 days. RESULTS The median prethrombectomy National Institutes of Health Stroke Scale (NIHSS) score was 25.50 (interquartile range: 21.00-29.00); the median prethrombectomy Glasgow Coma Scale (GCS) score was 8.00 (5.00-9.75). Thirty patients (83.3%) had atherosclerotic stenosis of the occluded artery, and 25 underwent angioplasty (69.4%). Recanalization was successful (Thrombolysis in Cerebral Infarction grade: 2b-3) in 34 patients (94.4%). Six symptomatic intracranial hemorrhages (16.67%) occurred. Favorable outcomes (modified Rankin scale [mRS] score: 0-2) were achieved in 27.8% patients (10/36). The overall mortality rate was 30.6% (11/36) at 90 days. On univariate analysis, low prethrombectomy GCS and high post-thrombectomy NIHSS scores were associated with poor outcomes (mRS score >2) and mortality. Prethrombectomy unconsciousness, onset-to-recanalization time > 10.5 hours, and severe stenosis were associated with poor outcomes. Age ≥ 60 years was associated with mortality. CONCLUSIONS Endovascular treatment with the Solitaire device yielded high recanalization rates in ABAO patients and favorable clinical outcomes in approximately one third of patients. Intracranial stenosis was the main cause of occlusion. Angioplasty was commonly performed during mechanical thrombectomy to improve recanalization and prognosis. Early recanalization and better prethrombectomy status predicted better outcomes.

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.

Functional assessment of cerebral artery stenosis: A pilot study based on computational fluid dynamics

The fractional pressure ratio is introduced to quantitatively assess the hemodynamic significance of severe intracranial stenosis. A computational fluid dynamics-based method is proposed to non-invasively compute the FPRCFD and compared against fractional pressure ratio measured by an invasive technique. Eleven patients with severe intracranial stenosis considered for endovascular intervention were recruited and an invasive procedure was performed to measure the distal and the aortic pressure (Pd and Pa). The fractional pressure ratio was calculated as P d / P a . The computed tomography angiography was used to reconstruct three-dimensional (3D) arteries for each patient. Cerebral hemodynamics was then computed for the arteries using a mathematical model governed by Navier–Stokes equations and with the outflow conditions imposed by a model of distal resistance and compliance. The non-invasive P d - CFD , P a - CFD , and FPRCFD were then obtained from the computational fluid dynamics calculation using a 16-core parallel computer. The invasive and non-invasive parameters were tested by statistical analysis. For this group of patients, the computational fluid dynamics method achieved comparable results with the invasive measurements. The fractional pressure ratio and FPRCFD are very close and highly correlated, but not linearly proportional, with the percentage of stenosis. The proposed computational fluid dynamics method can potentially be useful in assessing the functional alteration of cerebral stenosis.

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.

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.

Collateral circulation alters downstream hemodynamic stress caused by intracranial atherosclerotic stenosis

Abstract Objectives: Fractional flow reserve (FFR) accurately predicts the degree of stenosis and is now widely used to identify clinically significant severe coronary artery lesions. In the current study, we utilized a similar indicator, fractional flow (FF), to determine the hemodynamic impact of symptomatic intracranial atherosclerotic stenosis (ICAS) and to assess the correlation of FF with the severity of stenosis and collateral circulation. Methods: Patients with symptomatic ICAS (70–99% stenosis) confirmed on digital subtraction angiography (DSA) were consecutively recruited. FF was obtained during DSA examination with the use of pressure sensors and was measured as a ratio, comparing measurements distal to an ICAS lesion (Pd) and within the aorta (Pa). The degree of leptomeningeal collateralization was graded from zero (absent) to four (complete compensatory). The correlation between FF, anatomical stenosis, and collateral status was then analyzed. Results: Twenty-five patients with a mean age of 55.6 years were analyzed. The median percentage of stenosis and median FF were 82.3 and 0.68%, respectively. Eleven patients were found to have poor collateralization (grade 0-2), and fourteen patients were identified with good collateral circulation (grade 3-4). Overall, the hemodynamic impact of an atherosclerotic lesions worsened (decreased FF) as the percentage of stenosis increased, although this did not reach statistical significance (r = −0.398, p = 0.06). However, the status of collateralization significantly altered this correlation, worsening the hemodynamic impact in patients with poor collateral circulation (r = −0.677, p = 0.032). There was no difference in patients with good collateral circulation (r = −0.279, p = 0.356). Conclusion: An anatomically severe (70–99%) symptomatic ICAS lesion may generate significant hemodynamic stress downstream as assessed by the indicator FF, particularly in patients with poor collateral circulation. Further, good collateralization may mitigate this hemodynamic impact, partially explaining the protective effect of collateral circulation against recurrent stroke in such patients.