Factors influencing the efficacy of recombinant tissue plasminogen activator: Implications for ischemic stroke treatment.

Intravenous thrombolysis with a recombinant tissue plasminogen activator (rt-PA) is the first-line treatment of acute ischemic stroke. However, successful recanalization is relatively low and the underlying processes are not completely understood. The goal was to provide insights into clinically important factors potentially limiting rt-PA efficacy such as clot size, rt-PA concentration, clot age and also rt-PA in combination with heparin anticoagulant. We established a static in vitro thrombolytic model based on red blood cell (RBC) dominant clots prepared using spontaneous clotting from the blood of healthy donors. Thrombolysis was determined by clot mass loss and by RBC release. The rt-PA became increasingly less efficient for clots larger than 50 µl at a clinically relevant concentration of 1.3 mg/l. A tenfold decrease or increase in concentration induced only a 2-fold decrease or increase in clot degradation. Clot age did not affect rt-PA-induced thrombolysis but 2-hours-old clots were degraded more readily due to higher activity of spontaneous thrombolysis, as compared to 5-hours-old clots. Finally, heparin (50 and 100 IU/ml) did not influence the rt-PA-induced thrombolysis. Our study provided in vitro evidence for a clot size threshold: clots larger than 50 µl are hard to degrade by rt-PA. Increasing rt-PA concentration provided limited thrombolytic efficacy improvement, whereas heparin addition had no effect. However, the higher susceptibility of younger clots to thrombolysis may prompt a shortened time from the onset of stroke to rt-PA treatment.

Functional Outcome and Hemorrhage Rates After Bridging Therapy With Tenecteplase or Alteplase in Patients With Large Ischemic Core.

BACKGROUND AND OBJECTIVES: IV tenecteplase is an alternative to alteplase before mechanical thrombectomy (MT) in patients with large-vessel occlusion (LVO) ischemic stroke. Little data are available on its use in patients with large ischemic core. We aimed to compare the efficacy and safety of both thrombolytics in this population. METHODS: We conducted a retrospective analysis of patients with anterior circulation LVO strokes and diffusion-weighed imaging Alberta Stroke Program Early CT Score (DWI-ASPECTS) ≤5 treated with tenecteplase or alteplase before MT from the TETRIS (tenecteplase) and ETIS (alteplase) French multicenter registries. Primary outcome was reduced disability at 3 months (ordinal analysis of the modified Rankin scale [mRS]). Safety outcomes were 3-month mortality, parenchymal hematoma (PH), and symptomatic intracranial hemorrhage (sICH). We used propensity score overlap weighting to reduce baseline differences between treatment groups. RESULTS: We analyzed 647 patients (tenecteplase: n = 194; alteplase: n = 453; inclusion period 2015-2022). Median (interquartile range) age was 71 (57-81) years, with NIH Stroke Scale score 19 (16-22), DWI-ASPECTS 4 (3-5), and last seen well-to-IV thrombolysis and puncture times 165 minutes (130-226) and 260 minutes (203-349), respectively. After MT, the successful reperfusion rate was 83.1%. After propensity score overlap weighting, all baseline variables were well balanced between both treatment groups. Compared with patients treated with alteplase, patients treated with tenecteplase had better 3-month mRS (common odds ratio [OR] for reduced disability: 1.37, 1.01-1.87, p = 0.046) and lower 3-month mortality (OR 0.52, 0.33-0.81, p < 0.01). There were no significant differences between thrombolytics for PH (OR 0.84, 0.55-1.30, p = 0.44) and sICH incidence (OR 0.70, 0.42-1.18, p = 0.18). DISCUSSION: Our data are encouraging regarding the efficacy and reassuring regarding the safety of tenecteplase compared with that of alteplase in bridging therapy for patients with LVO strokes and a large ischemic core in routine clinical care. These results support its consideration as an alternative to alteplase in bridging therapy for patients with large ischemic cores. TRIALS REGISTRATION INFORMATION: NCT03776877 (ETIS registry) and NCT05534360 (TETRIS registry). CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that patients with anterior circulation LVO stroke and DWI-ASPECTS ≤5 treated with tenecteplase vs alteplase before MT experienced better functional outcomes and lower mortality at 3 months.

Pressure ulcer development in patients treated for acute ischaemic stroke.

OBJECTIVE: The aim of this study was to determine the incidence of pressure ulcers (PUs) in patients treated for acute ischaemic stroke (AIS) and to evaluate comorbid/confounding factors. METHOD: The study included patients treated for AIS who were divided into three treatment groups: those receiving intravenous tissue plasminogen activator therapy (tPA); patients receiving mechanical thrombectomy (MT); and those receiving both tPA and MT. PUs were classified according to the international classification system and factors that may influence their development were investigated. RESULTS: A total of 242 patients were included in this study. The incidence of PUs in patients treated for AIS was 7.4%. Most PUs were located on the sacrum (3.7%), followed by the gluteus (3.3%) and trochanter (2.9%). With regards to PU classification: 29% were stage I; 34% were stage II; and the remainder were stage III. Age was not a significant factor in the development of PUs (p=0.172). Patients in the tPA group had a lower PU incidence (2.3%) than patients in the tPA+MT group (15.7%) and MT group (12.1%) (p=0.001). Patients with PUs had a longer period of hospitalisation (18.5±11.92 days) than patients without a PU (8.0±8.52 days) (p=0.000). National Institute of Health Stroke Scale (NIHSS) scores at admission were higher in patients with PUs than in patients without a PU (14.33±4.38 versus 11.08±5.68, respectively; p=0.010). The difference in presence of comorbidities between patients with and without PUs (p=0.922) and between treatment groups (p=0.677) were not statistically significant. The incidence of PUs was higher in patients requiring intensive care, but this difference was not statistically significant (p=0.089). CONCLUSION: In this study, patients treated for AIS with high NIHSS scores at admission and/or receiving MT were at higher risk for PUs, and so particular attention should be given to these patients in order to prevent PU development.

The impact of intensive blood pressure management in the post-thrombolysis setting: a real-world observational study.

AIM: Systolic blood pressure (SBP) >180mmHg following stroke thrombolysis has been associated with increased bleeding and poorer outcome. Aiming for the guideline SBP of <180mmHg often leads to SBP overshoot, as treatment is only triggered if this threshold is passed. We tested whether a lower target would result in fewer high SBP protocol violations. METHOD: This is a single-centre, sequential comparison of two blood pressure protocols. Between 2013 and 2017, the guideline-based post-thrombolysis SBP target of <180mmHg was compared with a new protocol aiming for 140-160mmHg. The primary outcome was rate of patients with SBPs >180mmHg. Secondary outcomes included rates of SBP <120 mmHg, antihypertensive infusion use, symptomatic intracerebral haemorrhage (sICH) and 3-month functional independence (modified Rankin Score [mRS] 0-2). Results were adjusted for age, baseline function and stroke severity using regression analysis. RESULTS: During the 23 months preceding and 18 months following the transition to the new protocol, 68 and 100 patients were thrombolysed respectively. Baseline characteristics were similar between groups. The odds of one or more SBPs >180mmHg trended lower in the intensive group (adjusted odds ratio [aOR] 0.61; 95% confidence interval [CI] 0.32-1.17; p=0.14). There was a higher rate of SBPs <120mmHg (aOR 3.09; 95% CI 1.49-6.40; p=0.002) in the intensive BP protocol group. sICH rate and 3-month mRS 0-2 were similar between groups. CONCLUSIONS: The more intensive post-thrombolysis BP protocol was associated with a significant increase in sub-optimally low BP events, with a non-significant trend toward fewer high BP protocol violations and unaffected patient outcomes.

Efficacy and safety of antithrombotic therapy for preventing and treating pediatric thromboembolic disease: a systematic review.

This review used traditional and network meta-analyses (NMA) to conduct a comprehensive study of antithrombotic therapies in children with thromboembolic disease. We searched the PubMed, Embase, Cochrane Library, Web of Science and ClinicalTrials.gov databases from their inception to 26 February, 2023. And we finally included 16 randomized controlled trials. In the prevention of thromboembolic events (TEs), the use of anticoagulants had a low risk of TEs (relative risk (RR) 0.73, 95% CI 0.56 to 0.94) and a high risk of minor bleeding (RR 1.43, 95% CI 1.09 to 1.86) compared with no anticoagulants. In the treatment of TEs, direct oral anticoagulants (DOACs) were not inferior to standard anticoagulation in terms of efficacy and safety outcomes. In NMA, rivaroxaban and apixaban showed the lowest risk for TEs and major or clinically relevant nonmajor bleeding. According to the overall assessment of efficacy and safety, dabigatran may be the best choice for children with thromboembolic disease. The results of our study will provide references and suggestions for clinical drug selection.

Predicting ineffective thrombolysis in acute ischemic stroke with clinical and biochemical markers.

**Ischemic stroke remains a leading cause of morbidity and mortality globally. Despite the advances in thrombolytic therapy, notably recombinant tissue plasminogen activator (rtPA), patient outcomes are highly variable. This study aims to introduce a novel predictive model, the Acute Stroke Thrombolysis Non-Responder Prediction Model (ASTN-RPM), to identify patients unlikely to benefit from rtPA within the critical early recovery window. We conducted a retrospective cohort study at Baoding No.1 Central Hospital including 709 adult patients diagnosed with acute ischemic stroke and treated with intravenous alteplase within the therapeutic time window. The ASTN-RPM was developed using Least Absolute Shrinkage and Selection Operator (LASSO) regression technique, incorporating a wide range of biomarkers and clinical parameters. Model performance was evaluated using Receiver Operating Characteristic (ROC) curves, calibration plots, and Decision Curve Analysis (DCA). ASTN-RPM effectively identified patients at high risk of poor response to thrombolysis, with an AUC of 0.909 in the training set and 0.872 in the validation set, indicating high sensitivity and specificity. Key predictors included posterior circulation stroke, high admission NIHSS scores, extended door to needle time, and certain laboratory parameters like homocysteine levels. The ASTN-RPM stands as a potential tool for refining clinical decision-making in ischemic stroke management. By anticipating thrombolytic non-response, clinicians can personalize treatment strategies, possibly improving patient outcomes and reducing the burden of ineffective interventions. Future studies are needed for external validation and to explore the incorporation of emerging biomarkers and imaging data.

In ischemic stroke, adding IV thrombolysis ≤2 h after symptom onset to thrombectomy was associated with benefit.

SOURCE CITATION: Kaesmacher J, Cavalcante F, Kappelhof M, et al; IRIS Collaborators. Time to treatment with intravenous thrombolysis before thrombectomy and functional outcomes in acute ischemic stroke: a meta-analysis. JAMA. 2024;331:764-777. 38324409.

Spontaneous intercostal artery bleeding occurring simultaneously in numerous vessels during antithrombotic therapy with mechanical circulatory support: a case report.

BACKGROUND: Intercostal artery bleeding often occurs in a single vessel; in rare cases, it can occur in numerous vessels, making it more difficult to manage. CASE PRESENTATION: A 63-year-old Japanese man was admitted to the emergency department owing to sudden chest and back pain, dizziness, and nausea. Emergency coronary angiography revealed myocardial infarction secondary to right coronary artery occlusion. After intra-aortic balloon pumping, percutaneous coronary intervention was performed in the right coronary artery. At 12 hours following percutaneous coronary intervention, the patient developed new-onset left anterior chest pain and hypotension. Contrast-enhanced computed tomography revealed 15 sites of contrast extravasation within a massive left extrapleural hematoma. Emergency angiography revealed contrast leakage in the left 6th to 11th intercostal arteries; hence, transcatheter arterial embolization was performed. At 2 days after transcatheter arterial embolization, his blood pressure subsequently decreased, and contrast-enhanced computed tomography revealed the re-enlargement of extrapleural hematoma with multiple sites of contrast extravasation. Emergency surgery was performed owing to persistent bleeding. No active arterial hemorrhage was observed intraoperatively. Bleeding was observed in various areas of the chest wall, and an oxidized cellulose membrane was applied following ablation and hemostasis. The postoperative course was uneventful. CONCLUSION: We report a case of spontaneous intercostal artery bleeding occurring simultaneously in numerous vessels during antithrombotic therapy with mechanical circulatory support that was difficult to manage. As bleeding from numerous vessels may occur during antithrombotic therapy, even without trauma, appropriate treatments, such as transcatheter arterial embolization and surgery, should be selected in patients with such cases.

[Therapeutic effect of intravenous thrombolysis with tenecteplase on patients with post awakening branch atheromatous disease].

Objective: To investigate the efficacy and safety of intravenous thrombolysis with Tenecteplase (TNK) in patients with post-awakening branch atheromatous disease (BAD). Methods: A retrospective collection was conducted on 178 patients with post-awakening BAD admitted to the Stroke Centre of Zhengzhou People's Hospital from January 2017 to June 2023, who had a mismatch in DWI/FLAIR on magnetic resonance imaging. The patients were divided into thrombolysis group (60 patients) and control group (118 patients) according to whether or not they were applied to intravenous thrombolysis by TNK. Propensity score matching (PSM) was used to pair and balance the confounding factors at 1∶1 between the two groups, and the 90-d long-term prognosis of the patients was assessed using the modified Rankin Scale (mRS) and the Barthel Index (BI). The National Institutes of Health Stroke Scale (NIHSS) score was used to compare the early neurological changes between the two groups.The differences in clinical outcomes were compared between the two groups. Results: Fifty-two pairs of patients, 65 males and 39 females, aged (60±9) years, were successfully matched by PSM. The thrombolysis group had lower NIHSS score than that of the control group at 24 h, 7 d, 14 d after treatment or at discharge [3(2, 5) vs 4(3, 7), 3(2, 5) vs 4(3, 5), and 2(1, 4) vs 3(2, 4)], and shorter hospital stay than that of the control group [9(7, 12) d vs 11(9, 13) d], and at the same time, the thrombolysis group was less likely to experience early neurological deterioration (END) [9.6% (5/52) vs 28.9% (15/52)], and the proportion of 90 d mRS≤1, mRS≤2, and BI scores were higher than those in the control group [63.5% (33/52) vs 30.8% (16/52), 82.7% (43/52) vs 59.6% (31/52), and (91±8) points vs (82±8) points ], all differences were statistically significant (P<0.05). The percentage of mRS≥4 points was higher in the control group than that in the thrombolysis group [23.1% (12/52) vs 7.7% (4/52)]. One case of intracranial haemorrhage occurred in the thrombolysis group, and 1 case in the control group died of pulmonary infection within 90 d of follow-up, with a case-fatality rate of 1.9% (1/52). Conclusion: In the patients with post-awakening BAD screened by MRI, TNK intravenous thrombolysis can significantly reduce the risk of END, improving long-term prognosis and has a high safety.

Adoption of antithrombotic stewardship and utilization of clinical decision support systems-A questionnaire-based survey in Dutch hospitals.

Antithrombotics require careful monitoring to prevent adverse events. Safe use can be promoted through so-called antithrombotic stewardship. Clinical decision support systems (CDSSs) can be used to monitor safe use of antithrombotics, supporting antithrombotic stewardship efforts. Yet, previous research shows that despite these interventions, antithrombotics continue to cause harm. Insufficient adoption of antithrombotic stewardship and suboptimal use of CDSSs may provide and explanation. However, it is currently unknown to what extent hospitals adopted antithrombotic stewardship and utilize CDSSs to support safe use of antithrombotics. A semi-structured questionnaire-based survey was disseminated to 12 hospital pharmacists from different hospital types and regions in the Netherlands. The primary outcome was the degree of antithrombotic stewardship adoption, expressed as the number of tasks adopted per hospital and the degree of adoption per task. Secondary outcomes included characteristics of CDSS alerts used to monitor safe use of antithrombotics. All 12 hospital pharmacists completed the survey and report to have adopted antithrombotic stewardship in their hospital to a certain degree. The median adoption of tasks was two of five tasks (range 1-3). The tasks with the highest uptake were: drafting and maintenance of protocols (100%) and professional's education (58%), while care transition optimization (25%), medication reviews (8%) and patient counseling (8%) had the lowest uptake. All hospitals used a CDSS to monitor safe use of antithrombotics, mainly via basic alerts and less frequently via advanced alerts. The most frequently employed alerts were: identification of patients using a direct oral anticoagulant (DOAC) or a vitamin K antagonist (VKA) with one or more other antithrombotics (n = 6) and patients using a VKA to evaluate correct use (n = 6), both reflecting basic CDSS. All participating hospitals adopted antithrombotic stewardship, but the adopted tasks vary. CDSS alerts used are mainly basic in their logic.

Histotripsy and Catheter-Directed Lytic: Efficacy in Highly Retracted Porcine Clots In Vitro.

OBJECTIVE: Standard treatment for deep vein thrombosis (DVT) involves catheter-directed anticoagulants or thrombolytics, but the chronic thrombi present in many DVT cases are often resistant to this therapy. Histotripsy has been found to be a promising adjuvant treatment, using the mechanical action of cavitating bubble clouds to enhance thrombolytic activity. The objective of this study was to determine if histotripsy enhanced recombinant tissue plasminogen activator (rt-PA) thrombolysis in highly retracted porcine clots in vitro in a flow model of occlusive DVT. METHODS: Highly retracted porcine whole blood clots were treated for 1 h with either catheter-directed saline (negative control), rt-PA (lytic control), histotripsy, DEFINITY and histotripsy or the combination of rt-PA and histotripsy with or without DEFINITY. Five-cycle, 1.5 MHz histotripsy pulses with a peak negative pressure of 33.2 MPa and pulse repetition frequency of 40 Hz were applied along the clot. B-Mode and passive cavitation images were acquired during histotripsy insonation to monitor bubble activity. RESULTS: Clots subjected to histotripsy with and without rt-PA exhibited greater thrombolytic efficacy than controls (7.0% flow recovery or lower), and histotripsy with rt-PA was more efficacious than histotripsy with saline (86.1 ± 10.2% compared with 61.7 ± 19.8% flow recovery). The addition of DEFINITY to histotripsy with or without rt-PA did not enhance either thrombolytic efficacy or cavitation dose. Cavitation dose generally did not correlate with thrombolytic efficacy. CONCLUSION: Enhancement of thrombolytic efficacy was achieved using histotripsy, with and without catheter-directed rt-PA, in the presence of physiologic flow. This suggests these treatments may be effective as therapy for DVT.

Role of anticoagulation in non-ST-elevation myocardial infarction: a contemporary narrative review.

INTRODUCTION: Anticoagulants play a vital role as part of the antithrombotic therapy of myocardial infarction and are complementary to antiplatelet therapies. In the acute setting, the rationale for their use is to antagonize the ongoing clotting cascade including during percutaneous coronary intervention. Anticoagulation may be an important part of the longer-term antithrombotic strategy especially in patients who have other existing indications (e.g. atrial fibrillation) for their use. AREAS COVERED: In this narrative review, the authors provide a contemporary summary of the anticoagulation strategies of patients presenting with NSTEMI, both in terms of anticoagulation during the acute phase as well as suggested antithrombotic regimens for patients who require long-term anticoagulation for other indications. EXPERT OPINION: Patients presenting with non-ST-elevation myocardial infarction (NSTEMI) should be initiated on anticoagulation (e.g. heparin/low molecular weight heparin) for the initial hospitalization period for those medically managed or until percutaneous coronary intervention. Longer term management of NSTEMI for patients with an existing indication for long-term anticoagulation should comprise triple antithrombotic therapy of anticoagulant (preferably DOAC) with aspirin and clopidogrel for up to 1 month (typically 1 week or until hospital discharge), followed by DOAC plus clopidogrel for up to 1 year, and then DOAC monotherapy thereafter.

The effect of current antithrombotic therapy on mortality in nursing home residents with COVID-19: a multicentre retrospective cohort study.

BACKGROUND: The first wave of COVID led to an alarmingly high mortality rate among nursing home residents (NHRs). In hospitalised patients, the use of anticoagulants may be associated with a favourable prognosis. However, it is unknown whether the use of antithrombotic medication also protected NHRs from COVID-19-related mortality. OBJECTIVES: To investigate the effect of current antithrombotic therapy in NHRs with COVID-19 on 30-day all-cause mortality during the first COVID-19 wave. METHODS: We performed a retrospective cohort study linking electronic health records and pharmacy data in NHRs with COVID-19. A propensity score was used to match NHRs with current use of therapeutic dose anticoagulants to NHRs not using anticoagulant medication. The primary outcome was 30-day all-cause mortality, which was evaluated using a logistic regression model. In a secondary analysis, multivariable logistic regression was performed in the complete study group to compare NHRs with current use of therapeutic dose anticoagulants and those with current use of antiplatelet therapy to those without such medication. RESULTS: We included 3521 NHRs with COVID-19 based on a positive RT-PCR for SARS-CoV-2 or with a well-defined clinical suspicion of COVID-19. In the matched propensity score analysis, NHRs with current use of therapeutic dose anticoagulants had a significantly lower all-cause mortality (OR = 0.73; 95% CI: 0.58-0.92) compared to NHRs who did not use therapeutic anticoagulants. In the secondary analysis, current use of therapeutic dose anticoagulants (OR: 0.62; 95% CI: 0.48-0.82) and current use of antiplatelet therapy (OR 0.80; 95% CI: 0.64-0.99) were both associated with decreased mortality. CONCLUSIONS: During the first COVID-19 wave, therapeutic anticoagulation and antiplatelet use were associated with a reduced risk of all-cause mortality in NHRs. Whether these potentially protective effects are maintained in vaccinated patients or patients with other COVID-19 variants, remains unknown.

Efficacy and safety of catheter-based thrombectomy versus catheter-directed thrombolysis in acute pulmonary embolism.

Data comparing catheter-based thrombectomy (CBT) and catheter-directed thrombolysis (CDT) in acute pulmonary embolism are lacking. To address this, we performed a meta-analysis of prospective and retrospective studies of CBT and compared it to performance goal rates of mortality and major bleeding from a recently published network meta-analysis. When compared with performance goal for CDT based on historical studies, CBT was noninferior for all-cause mortality (6.0% vs 6.87%; P-valueNI < .001), non-inferior and superior for major bleeding (4.9% vs 11%; P-valueNI < .001 and P < .001 for superiority).

Advances in Nano-Functional Materials in Targeted Thrombolytic Drug Delivery.

Thrombotic disease has been listed as the third most fatal vascular disease in the world. After decades of development, clinical thrombolytic drugs still cannot avoid the occurrence of adverse reactions such as bleeding. A number of studies have shown that the application of various nano-functional materials in thrombus-targeted drug delivery, combined with external stimuli, such as magnetic, near-infrared light, ultrasound, etc., enrich the drugs in the thrombus site and use the properties of nano-functional materials for collaborative thrombolysis, which can effectively reduce adverse reactions such as bleeding and improve thrombolysis efficiency. In this paper, the research progress of organic nanomaterials, inorganic nanomaterials, and biomimetic nanomaterials for drug delivery is briefly reviewed.