Clinical potential of intra-arterial thrombolytic therapy in patients with acute ischaemic stroke

Safety and efficacy of tirofiban treatment in the endovascular treatment of patients with acute ischaemic stroke - A meta-analysis

OBJECT

The use of endovascular therapy (EVT) has become a widespread strategy for the clinical management of acute ischemic stroke (AIS). However, the combination of arterial injection of tirofiban with EVT for AIS continues to be a subject of controversy. This meta-analysis was conducted to assess the safety and efficacy of this treatment approach.

METHODS

Relevant studies were identified through a systematic literature search in Pubmed, EMBASE, Web of Science, and Cochrane Library databases, covering articles published from January 2010 to January 2023. The efficacy outcomes included favorable functional outcomes, recanalization rates, and safety outcomes including mortality and symptomatic intracranial hemorrhage (sICH).

RESULTS

The meta-analysis consisted of data from 13 studies, which included 1 randomized controlled trial (RCT), 7 prospective cohort studies, and 5 retrospective cohort studies, encompassing a total of 3477 patients. The study results indicate that the intra-arterial (IA) tirofiban+EVT for AIS is associated with significant improvements in favorable functional outcomes (OR, 1.21; 95%CI, 1.05-1.40; P = 0.009) and recanalization rate (OR, 1.33; 95%CI, 1.06-1.65; P = 0.01), as well as significant reductions in mortality rates (OR, 0.65; 95%CI, 0.53-0.79; P = 0.0001). Subgroup analysis revealed that administering a maintenance dose of intravenous (IV) tirofiban post-EVT was significantly associated with improved functional outcomes and reduced mortality in patients. In addition, there was no increase in the incidence of sICH (OR, 0.92; 95%CI, 0.71-1.20; P = 0.54).

CONCLUSION

The administration of Intra-arterial tirofiban combined with EVT is an effective and safe treatment strategy for AIS, and postoperative maintenance doses of intravenous tirofiban may be more effective than IA only.

An in vitro comparative study on clot lysis efficiency of urokinase and reteplase with the synergy of ultrasound needle

Objectives

Ultrasound Needle, which is an improved ultrasonic horn device, has shown great potential for promoting the diffusion of thrombolytic drugs within clots and enhancing clot lysis efficiency. However, the clot lysis efficiency of different thrombolytic drugs with the synergy of Ultrasound Needle remains unknown. In this study, we aimed to compare the lysis efficiency of the non-fibrin-specific drug urokinase and fibrin-specific drug reteplase with the synergy of Ultrasound Needle.

Materials and methods

Twenty-five milliliters of human blood was incubated for 1.5 h to form in vitro clots and then received the corresponding treatment protocols: control group (normal saline), US group (10 min of Ultrasound Needle treatment), UK group (30000IU of urokinase), r-PA group (2 mg of reteplase), US + UK group, and US + r-PA group. After treatment, the morphological changes of the clots were analyzed by B-mode ultrasound imaging and hematoxylin and eosin (H&E) staining. Lysis efficiency was evaluated based on the relative end weight (final weight/initial weight). The fibrin density of the different groups after treatment was assessed by immunofluorescence staining.

Results

Morphological examination and relative end weight analysis showed that combination therapies induced a more thorough dissolution of clots compared with single therapies, and the US + r-PA group exhibited higher lysis efficiency than the US + UK group. In addition, immunofluorescence staining showed that the US + r-PA group had fewer remaining thrombus fibrins than the US + UK group after treatment.

Conclusions

The Ultrasound Needle can significantly improve the clot lysis efficiency of both fibrinolytic drugs, and fibrin-specific reteplase exhibited superior lysis efficiency over non-fibrin-specific urokinase with the synergy of the Ultrasound Needle.

Adaptive wireless millirobotic locomotion into distal vasculature

Microcatheters have enabled diverse minimally invasive endovascular operations and notable health benefits compared with open surgeries. However, with tortuous routes far from the arterial puncture site, the distal vascular regions remain challenging for safe catheter access. Therefore, we propose a wireless stent-shaped magnetic soft robot to be deployed, actively navigated, used for medical functions, and retrieved in the example M4 segment of the middle cerebral artery. We investigate shape-adaptively controlled locomotion in phantoms emulating the physiological conditions here, where the lumen diameter shrinks from 1.5 mm to 1 mm, the radius of curvature of the tortuous lumen gets as small as 3 mm, the lumen bifurcation angle goes up to 120°, and the pulsatile flow speed reaches up to 26 cm/s. The robot can also withstand the flow when the magnetic actuation is turned off. These locomotion capabilities are confirmed in porcine arteries ex vivo. Furthermore, variants of the robot could release the tissue plasminogen activator on-demand locally for thrombolysis and function as flow diverters, initiating promising therapies towards acute ischemic stroke, aneurysm, arteriovenous malformation, dural arteriovenous fistulas, and brain tumors. These functions should facilitate the robot's usage in new distal endovascular operations.

A critical analysis of intra-arterial thrombolytic doses in acute ischemic stroke treatment

BACKGROUND

Intra-arterial thrombolytics (IAT) such as Alteplase, Tenecteplase, and Reteplase are currently used in patients with acute ischemic stroke in varying doses. We evaluated the relationship of IA thrombolytic dose with angiographic recanalization, intracerebral hemorrhage (ICH) rates, and clinical outcomes at three comprehensive stroke centers.

METHODS

We stratified patients who underwent endovascular treatment into tertiles based on intra-arterial thrombolytic dose administered: lower tertile (range 1.5-5 mg), middle tertile (range 6-10 mg), and upper tertile (range 10.3-68.5 mg) of rt-PA equivalent. The rates of angiographic recanalization, ICH, and favorable clinical outcomes (discharge modified Rankin score [mRS] = 0-2) were ascertained and compared within the three tertiles. Logistic regression analyses were performed to determine the association between IA thrombolytic dosages and angiographic recanalization, ICH, and favorable clinical outcomes after adjusting for potential confounders.

RESULTS

A total of 197 patients were treated with IAT; mean age ±SD was 65.6 ± 16 years; 105 (53.3%) were women. Ninety-one (46.2%) patients received both IVT and IAT. IA rt-PA equivalent dose was not different between the patients with and without ICH [mean (mg) ± SD, 9.8 ± 6.1 versus 9.8 ± 9.5, p = 0.9]. We did not find any relation between increasing doses of IAT (from 2 to 69 mg rt-PA equivalent) and symptomatic or asymptomatic ICH: (p = 0.1630) and (p = 0.6702), respectively. Multivariate analysis demonstrated that IAT dose was not associated with ICH (OR 1.0, 95% CI 0.97-1.07, p = 0.3919) or favorable outcome (OR, 1.00, 95% CI 0.95-1.06, p = 0.7375). In a subset analysis of IVT patients, total doses ranged from 48.2 to 149 mg and were not associated with either symptomatic (p = 0.23) or asymptomatic (p = 0.24) ICHs.

CONCLUSION

Our study demonstrates that IAT in doses up to 69 mg is safe without any evidence of dose-related ICHs even in those patients who had received IVT.

Endovascular therapies for noncoronary atherosclerosis in the elderly: supra-aortic vessels and thoracoabdominal aorta lesions

Due to the aging of the population and the fact that people are living longer, there are increasing numbers of older patients with noncoronary atherosclerosis. Carotid and subclavian arteries are often the first involved vessels in atherosclerosis, and thoracoabdominal aortic involvement is becoming even more frequent. New techniques, such as intra-arterial thrombolysis, protection and thrombo-aspiration devices, and new stent graft designs are becoming available for percutaneous treatment of atherosclerosis in such vessels. In this review, the authors offer geriatric cardiologists an overview and an update of the most recent advances in techniques and results in the field of interventional treatments of atherosclerosis of supra-aortic vessels and thoracoabdominal aorta in the elderly.

Effects of vitamin C and aspirin in ischemic stroke-related lipid peroxidation: results of the AVASAS (Aspirin Versus Ascorbic acid plus Aspirin in Stroke) Study

A condition of oxidative stress is known to occur in ischemic stroke, the current therapeutic intervention of which is largely limited to thrombolysis. To assess the effect of vitamin C - in conjunction to aspirin - in ischemic stroke-related lipid peroxidation, we measured plasma levels of ascorbate, of 8,12-isoprostanes F2alpha-VI (8,12-iPF2alpha-VI) and activities and levels of a broad spectrum of antioxidant enzymes and micronutrients in stroke patients randomized to receive, from stroke onset and up to three months, either vitamin C (200 mg/day) plus aspirin (300 mg/day) or only aspirin (300 mg/day). By the end of the first week, patients treated with vitamin C plus aspirin had higher vitamin C levels (p = 0.02) and lower 8,12-iPF2alpha-VI levels (p = 0.01) than patients treated with aspirin alone. The significance was maintained for the increase of vitamin C after three months of therapy (p < 0.01). The clinical functional outcome for both groups of patients similarly ameliorated after three months of treatment. We conclude that vitamin C, at the dose of 200 mg/day and in conjunction with aspirin, significantly decreases ischemic stroke-related lipid peroxidation in humans. Further studies are warranted to clarify whether the use of vitamin C may add clinical long-term beneficial effects in patients with stroke.

Cholesterol in neurologic disorders of the elderly: stroke and Alzheimer’s disease

Mechanisms for the regulation of intracellular cholesterol levels in various types of brain and vascular cells are of considerable importance in our understanding of the pathogenesis of a variety of diseases, particularly atherosclerosis and Alzheimer's disease (AD). It is increasingly clear that conversion of brain cholesterol into 24-hydroxycholesterol and its subsequent release into the periphery is important for the maintenance of brain cholesterol homeostasis. Recent studies have shown elevated plasma concentrations of 24-hydroxycholesterol in patients with AD and vascular dementia, suggesting increased brain cholesterol turnover during neurodegeneration. The oxygenases involved in the degradation and excretion of cholesterol, including the cholesterol 24-hydroxylase and the 27-hydroxylase, are enzymes of the cytochrome P-450 family. This review focuses on the newly recognized importance of cholesterol and its oxygenated metabolites in the pathogenesis of ischemic stroke and AD. The reduction in stroke and AD risk in patients treated with cholesterol-lowering statins is also discussed.