Efficacy and safety of sonothombolysis versus non-sonothombolysis in patients with acute ischemic stroke: A meta-analysis of randomized controlled trials

Continuous transcranial ultrasound in large vessel stroke: Image guidance for high-intensity focused sonothrombolysis

BACKGROUND AND PURPOSE

Sonothrombolysis is a potential adjunctive therapy for large vessel occlusion (LVO) stroke. Bedside ultrasound image-guided high-intensity focused ultrasound (HIFU) therapy could deliver higher energy therapeutic ultrasound to the thrombus with higher precision than what was previously accomplished in human trials. The aim is to test the feasibility of diagnostic transcranial contrast-enhanced ultrasound (CEUS) to image the occlusion site and continuously maintain the guidance image on-target for a sufficient exposure time for HIFU to be effective during LVO stroke evaluation and treatment.

METHODS

This prospective, single center, observational cohort study included adult patients, presenting within 6 hours of stroke symptom onset, with LVO identified on computed tomography angiography (CTA). A hand-held CEUS imaging study was initiated following CTA and lasted up to 30 minutes. The primary outcome is the proportion of patients where a guidance CEUS image of the occlusion was achieved.

RESULTS

A CEUS image of the occluded artery was obtained in 32/35 of the included patients. The median total imaging time was 23 minutes (interquartile range 15-30). Patients undergoing thrombectomy had a lower total imaging time (17 vs. 29.5 minutes, p = .002). When imaging was successful, on-target image was maintained for only 58% (standard deviation 23.8%) of total imaging time. No complications related to CEUS were observed.

CONCLUSIONS

This feasibility study explored the use of diagnostic transcranial CEUS for continuous imaging of occlusion sites in LVO strokes. Challenges in maintaining target image during HIFU were identified, highlighting the need for technical advances for clinical application.

Sonothrombolysis for Ischemic Stroke

Stroke is a major cause of death and disability globally, with ischemic stroke being the predominant mechanism. While spontaneous recanalization may occur, significant neuronal injury would have occurred in the interim. Intravenous thrombolysis administered within the first 4.5 h after stroke onset and endovascular thrombectomy within 24 h in patients with a salvageable penumbra improves functional independence. Ultrasound has been shown in both in vivo and in vitro models to enhance clot lysis, even more-so in the presence of thrombolytic agents. The use of transcranial Doppler and transcranial color-coded Doppler ultrasound in acute IS has been reported in case series, case-controlled studies, and clinical trials. While ultrasound at a frequency of 300 kHz increases the risk of intracranial hemorrhage, the 2 MHz range ultrasound aids thrombolysis and improves recanalization without significantly increasing the risk of symptomatic intracranial hemorrhage. Despite this, functional independence was not increased in clinical trials, nor was a benefit shown with the adjunctive use of microbubbles or microspheres. Nonetheless, newer technologies such as endovascular ultrasound, endovascular delivery of microbubbles, and thrombolytic-filled microbubbles await clinical trials. More evidence is needed before sonothrombolysis can be routinely used in the hyperacute management of ischemic stroke.

Low-Intensity Ultrasound Reduces Brain Infarct Size by Upregulating Phosphorylated Endothelial Nitric Oxide in Mouse Model of Middle Cerebral Artery Occlusion

OBJECTIVE

There have been attempts to use therapeutic ultrasound (US) for the treatment of both experimental and clinical stroke. We hypothesized that low-intensity US has direct beneficial effects on the brain independent of cerebral blood flow (CBF) during middle cerebral artery occlusion (MCAO).

METHODS

Three groups of mice were studied. Group I included 84 mice with MCAO undergoing US treatment/no treatment at two US frequencies (0.25 and 1.05 MHz) with three different acoustic pressures at each frequency in which infarct size (IS) was measured 24 h later. Group II included 11 mice undergoing treatment based on best US results from group I animals in which the IS/risk area (RA) ratio was measured 24 h later. Group III included 38 normal mice undergoing US treatment/no treatment for assessment of CBF, tissue metabolite and protein expression and histopathology.

DISCUSSION

Ultrasound at both frequencies and most acoustic pressures resulted in reduction in IS in group I animals, with the best results obtained with 0.25 MHz at 2.0 MPa: IS was reduced 4-fold in the cerebral cortex, 1.5-fold in the caudate putamen and 3.5-fold in the cerebral hemisphere compared with control. US application in group III animals elicited only a marginal increase in CBF despite a 2.6-fold increase in phosphorylated endothelial nitric oxide synthase (p-eNOS)-S1177 and a corresponding decrease in p-eNOS-T494. Histopathology revealed no evidence of hemorrhage, inflammation or necrosis.

CONCLUSION

Low-intensity US at specific frequencies and acoustic pressures results in marked neuroprotection in a mouse model of stroke by modulation of p-eNOS independent of its effect on CBF.

Sonothrombolysis Promotes Improvement in Left Ventricular Wall Motion and Perfusion Scores after Acute Myocardial Infarction

BACKGROUND

It has recently been demonstrated that the application of high-energy ultrasound and microbubbles, in a technique known as sonothrombolysis, dissolves intravascular thrombi and increases the angiographic recanalization rate in patients with ST-segment-elevation myocardial infarction (STEMI).

OBJECTIVE

To evaluate the effects of sonothrombolysis on left ventricular wall motion and myocardial perfusion in patients with STEMI, using real-time myocardial perfusion echocardiography (RTMPE).

METHODS

One hundred patients with STEMI were randomized into the following 2 groups: therapy (50 patients treated with sonothrombolysis and primary coronary angioplasty) and control (50 patients treated with primary coronary angioplasty). The patients underwent RTMPE for analysis of left ventricular ejection fraction (LVEF), wall motion score index (WMSI), and number of segments with myocardial perfusion defects 72 hours after STEMI and at 6 months of follow-up. P < 0.05 was considered statistically significant.

RESULTS

Patients treated with sonothrombolysis had higher LVEF than the control group at 72 hours (50% ± 10% versus 44% ± 10%; p = 0.006), and this difference was maintained at 6 months of follow-up (53% ± 10% versus 48% ± 12%; p = 0.008). The WMSI was similar in the therapy and control groups at 72 hours (1.62 ± 0.39 versus 1.75 ± 0.40; p = 0.09), but it was lower in the therapy group at 6 months (1.46 ± 0.36 versus 1.64 ± 0.44; p = 0.02). The number of segments with perfusion defects on RTMPE was similar in therapy and control group at 72 hours (5.92 ± 3.47 versus 6.94 ± 3.39; p = 0.15), but it was lower in the therapy group at 6 months (4.64 ± 3.31 versus 6.57 ± 4.29; p = 0.01).

CONCLUSION

Sonothrombolysis in patients with STEMI resulted in improved wall motion and ventricular perfusion scores over time.

Sonothrombolysis in Patients With Acute Ischemic Stroke With Large Vessel Occlusion: An Individual Patient Data Meta-Analysis

BACKGROUND AND PURPOSE

Evidence about the utility of ultrasound-enhanced thrombolysis (sonothrombolysis) in patients with acute ischemic stroke (AIS) is conflicting. We aimed to evaluate the safety and efficacy of sonothrombolysis in patients with AIS with large vessel occlusion, by analyzing individual patient data of available randomized-controlled clinical trials.

METHODS

We included all available randomized-controlled clinical trials comparing sonothrombolysis with or without addition of microspheres (treatment group) to intravenous thrombolysis alone (control group) in patients with AIS with large vessel occlusion. The primary outcome measure was the rate of complete recanalization at 1 to 36 hours following intravenous thrombolysis initiation. We present crude odds ratios (ORs) and ORs adjusted for the predefined variables of age, sex, baseline stroke severity, systolic blood pressure, and onset-to-treatment time.

RESULTS

We included 7 randomized controlled clinical trials that enrolled 1102 patients with AIS. A total of 138 and 134 confirmed large vessel occlusion patients were randomized to treatment and control groups respectively. Patients randomized to sonothrombolysis had increased odds of complete recanalization compared with patients receiving intravenous thrombolysis alone (40.3% versus 22.4%; OR, 2.17 [95% CI, 1.03-4.54]; adjusted OR, 2.33 [95% CI, 1.02-5.34]). The likelihood of symptomatic intracranial hemorrhage was not significantly different between the 2 groups (7.3% versus 3.7%; OR, 2.03 [95% CI, 0.68-6.11]; adjusted OR, 2.55 [95% CI, 0.76-8.52]). No differences in the likelihood of asymptomatic intracranial hemorrhage, 3-month favorable functional and 3-month functional independence were documented.

CONCLUSIONS

Sonothrombolysis was associated with a nearly 2-fold increase in the odds of complete recanalization compared with intravenous thrombolysis alone in patients with AIS with large vessel occlusions. Further study of the safety and efficacy of sonothrombolysis is warranted.

Ultrasound-Responsive Cavitation Nuclei for Therapy and Drug Delivery

Therapeutic ultrasound strategies that harness the mechanical activity of cavitation nuclei for beneficial tissue bio-effects are actively under development. The mechanical oscillations of circulating microbubbles, the most widely investigated cavitation nuclei, which may also encapsulate or shield a therapeutic agent in the bloodstream, trigger and promote localized uptake. Oscillating microbubbles can create stresses either on nearby tissue or in surrounding fluid to enhance drug penetration and efficacy in the brain, spinal cord, vasculature, immune system, biofilm or tumors. This review summarizes recent investigations that have elucidated interactions of ultrasound and cavitation nuclei with cells, the treatment of tumors, immunotherapy, the blood-brain and blood-spinal cord barriers, sonothrombolysis, cardiovascular drug delivery and sonobactericide. In particular, an overview of salient ultrasound features, drug delivery vehicles, therapeutic transport routes and pre-clinical and clinical studies is provided. Successful implementation of ultrasound and cavitation nuclei-mediated drug delivery has the potential to change the way drugs are administered systemically, resulting in more effective therapeutics and less-invasive treatments.

Efficacy and Safety of Ginkgo Leaf Extract and Dipyridamole Injection for Ischemic Stroke: A Systematic Review and Meta Analysis

Objective: Ginkgo leaf extract and dipyridamole injection (GDI), a kind of Chinese medicine preparation, has been considered as a promising supplementary treatment for ischemic stroke. The aim of this study was to systematically evaluate the clinical efficacy and safety of GDI mediated therapy for ischemic stroke.

Methods: PubMed, Cochrane Library, Medline, Embase, Web of Science, Wanfang database, Chinese Scientific Journal Database (VIP), China National Knowledge Infrastructure (CNKI) and Chinese Biological Medicine Database (CBM), were searched systematically for clinical trials of conventional treatments combined with GDI for ischemic stroke. The reported outcomes including overall response, hemorrheology and blood lipid indexes, and adverse events were systematically investigated.

Results: Data from thirty-nine trials including 3,182 ischemic stroke patients were involved. The results indicated that, compared with conventional treatments alone, the combination of conventional treatments with GDI obviously improved the overall response (odds ratio [OR] = 4.14, 95% confidence interval [CI] = 3.26–5.25, P < 0.00001), neurological status (National Institutes of Health Stroke Scale, OR = −3.13, 95% CI = −3.98 to −2.28, P < 0.00001) and activity of daily living (Barthel Index score, OR = 14.10, 95% CI = 9.51–18.68, P < 0.00001) of patients. Moreover, the hemorheology and blood lipids indexes of ischemic stroke patients were also significantly ameliorated after the combined therapy (P < 0.01). The frequency of adverse events did not differ significantly between the two groups (P > 0.05).

Conclusion: Evidence from the meta-analysis suggested that the combination of conventional treatments and GDI is safe and more effective in treating ischemic stroke than conventional treatments alone. Therefore, GDI mediated therapy could be recommended as an adjuvant treatment for ischemic stroke.

Does the administration of sonothrombolysis along with tissue plasminogen activator improve outcomes in acute ischemic stroke? A systematic review and meta-analysis

This meta-analysis was conducted to assess the safety and efficacy of sonothrombolysis along with intravenous recombinant tissue plasminogen activator, alteplase (IV rtPA), in the management of acute ischemic stroke. Electronic databases were searched under different meSH terms without the restriction of time and language. 1415 studies were analyzed and seven studies that matched the inclusion criteria were selected. Multiple safety and efficacy outcomes were extracted. Our pooled analysis demonstrated that there is no significant difference between sonothrombolysis group and control group in preventing mortality (RR 1.10 [0.81, 1.50]; p = 0.55; I² = 0%) and intracranial hemorrhage (RR 1.11 [0.76, 1.63]; p = 0.59; i² = 0%), however, among the efficacy outcomes; complete recanalization after 60-120 min was achieved more effectively in the sonothrombolysis group (RR 2.11 [1.48, 3.03]; p ≤ 0.0001; I² = 0%). The rest of the efficacy outcomes like neurological improvement at 24 h (RR 1.20 [0.92, 1.57]; p = 0.18; I² = 40%) and excellent functional outcome after 3 months (RR 1.19 [0.93, 1.52]; p = 0.17; I² = 35%) showed no significant differences between the two groups. In subgroup analysis, we found that sonothrombolysis led to a better neurological improvement in patients who were less than 65 years of age (RR 1.20 [0.92, 1.57]; p = 0.05; I² = 40%). Moreover, there were no significant differences in the following of the subgroups assessed: (a) microsphere or microbubble use, (b) Ultrasound frequency (2 MHz or < 2 MHz), (c) transcranial Doppler (TCD) duration (1 h or 2 h), (d) age (≤ 65 or > 65).