Dose Of rt-PA Research Articles

Pharmacokinetics and pharmacodynamics of low doses of recombinant tissue plasminogen activator to establish a model for biosimilarity comparisons

BackgroundRecombinant tissue plasminogen activator (rt-PA) is a thrombolytic agent and essential in emergency medical care. Given recent supply shortages, the availability of biosimilar products is an urgent medical need. However, biosimilarity trials are difficult to perform in critically ill patients. ObjectivesThe aim of this pilot study was to investigate the pharmacokinetics and pharmacodynamics of low rt-PA doses to establish a model for testing proposed biosimilars in healthy volunteers. MethodsEight healthy volunteers received 0.02 to 0.05 mg/kg rt-PA on 3 study days; blood samples were obtained every 4 minutes after the end of the bolus infusion to measure rt-PA antigen levels by enzyme immunoassay, and the pharmacodynamics were assessed with rotational thromboelastometry. ResultsBolus infusion of low rt-PA doses was safe and well tolerated. Maximal plasma concentrations and the area under the curve increased dose-dependently. Time-concentration curves were clearly separated between the lower and the higher doses. As expected, the half-live of rt-PA was short (4.5-5 min), and representative for therapeutic doses. The intrasubject coefficient variations were moderate (<25%). Bolus infusion of rt-PA dose-dependently shortened lysis time and lysis onset time in both dose groups and caused maximum clot lysis of 100% in all participants. ConclusionIn conclusion, the pharmacokinetics of rt-PA was dose linear and displayed limited intrasubject variability even at subtherapeutic doses. The half-life and thus clearance of rt-PA was representative of full therapeutic doses. The lysis time was shortened in a dose and time-dependent fashion and was clearly distinguishable between doses. Thus, the model appears to be suitable and sensitive to test biosimilarity.

Targeted Thrombolysis with Magnetic Nanotherapeutics: A Translational Assessment.

Plasminogen activators, such as recombinant tissue-type plasminogen activators (rtPAs), while effective in treating thromboembolic diseases, often induce hemorrhagic complications due to non-specific enzyme activities in the systemic circulation. This study evaluated the targeting efficiency, efficacy, biodistribution, and potential toxicity of a rtPA covalently attached to chitosan-coated magnetic nanoparticles (chitosan-MNP-rtPA). The thrombolytic activity of a chitosan-MNP-rtPA was preserved by protection from an endogenous plasminogen activator inhibitor-1 (PAI-1) in whole blood and after circulation in vivo, as examined by thromboelastometry. Single-photon emission computed tomography (SPECT) demonstrated real-time retention of a 99mTc-MNP-rtPA induced by magnet application in a rat embolic model; an 80% reduction in rtPA dosage for a chitosan-MNP-rtPA with magnetic guidance was shown to restore blood flow. After treatment, iron deposition was observed in the reticuloendothelial systems, with portal edema and neutrophil infiltration in the liver at a ten-fold higher dose but not the regular dose. Nevertheless, no liver or renal toxicity was observed at this higher dose. In conclusion, the liver may still be the major deposit site of rtPA nanocomposites after targeted delivery; chitosan-coated MNPs are potentially amenable to target therapeutics with parenteral administration.

Intrapleural Fibrinolysis with Urokinase versus Alteplase in Complicated Pleural Effusions and Empyema: A Prospective Randomized Controlled Trial.

Intrapleural fibrinolytic therapy (IPFT) has been used as an effective agent since 1949 for managing complicated pleural effusion and empyema. Several agents, such as streptokinase, urokinase (UK), and recombinant tissue plasminogen activator (rt-PA), have been found to be effective with variable effectiveness. However, a head-tohead controlled trial comparing the efficacy of the most frequently used agents, i.e., UK and rt-PA (alteplase) for managing complicated pleural effusion has rarely been reported. A total of 50 patients were randomized in two intervention groups, i.e., UK and rt-PA. The dose of rt-PA was 10 mg, and that of UK was 1.0 lac units. UK was given thrice daily for 2 days, followed by clamping to allow the retainment of drugs in the pleural space for 2 hours. rt-PA was instilled into the pleural space twice daily for 2 days, and intercostal drainage was clamped for 1 hour. A total of 50 patients were enrolled into the study, of which 84% (n=42) were males and 16% (n=8) were females. Among them, 30 (60%) patients received UK, and 20 (40%) patients received alteplase as IPFT agents. The percentage of mean± standard deviation changes in pleural opacity was -33.0%±9.9% in the UK group and -41.0%±14.9% in the alteplase group, respectively (p=0.014). Pain was the most common adverse side effect, occurring in 60% (n=18) of the patients in the UK group and in 40% (n=8) of the patients in the alteplase group (p=0.24), while fever was the second most common side effect. Patients who reported early (within 6 weeks of onset of symptoms) showed a greater response than those who reported late for the intervention. IPFT is a safe and effective option for managing complicated pleural effusion or empyema, and newer agents, such as alteplase, have greater efficacy and a similar adverse effect profile when compared with conventional agents, such as UK.

Factors affecting improvement after intravenous administration of recombinant tissue plasminogen activator (rtPA) among patients with acute ischemic stroke: A historical cohort study.

One of the most effective treatments for patients with acute ischemic stroke (AIS) is intravenous recombinant tissue plasminogen activator (rtPA) which can minimize mortality and morbidities. In this historical cohort study, we investigate the factors affecting clinical outcomes after IV thrombolysis for AIS. We included 87 patients with acute ischemic stroke who were treated with rtPA between 2015 and 2019. Demographic and clinical data were recorded. The National Institutes of Health Stroke Scale (NIHSS) was used to assess the clinical outcomes. 36 patients showed lack of improvement at discharge. In unadjusted model, hypercholesterolemia was the only predictor of lack of improvement (P= 0.043; OR=0.304; CI= 0.096-0.963). After adjusting, hypertension (P= 0.018; OR= 0.18; CI= 0.043-0.749) and hypercholesterolemia (P= 0.008; OR= 8.68; CI= 1.773-42.54) were independent determinants of lack of clinical response. To evaluate risk factors in association with the duration of hospitalization, we found variables which lengthened hospitalization span including; age over 60 years (HR= 0.42 P= 0.002), hypercholesterolemia (HR= 2.19 P= 0.031), Angiotensin-converting enzyme (ACE) Inhibitors consumption (HR= 1.87 P= 0.022), and type of infarction (non-lacunar) (HR= 0.51 P= 0.026). Results indicated no considerable relationship between dose of rtPA and the appropriate response to treatment (OR=8.686 P= 0.324). The closer dose of rtPA goes up to standard range, the more chance of improvement will gain without increasing the risk of symptomatic intra-cerebral hemorrhage (SICH). Determining factors involved in intravenous reperfusion outcomes help physicians to identify the patients who benefit the most from rtPA.

Specific inhibition on PAI-1 reduces the dose of Alteplase for ischemic stroke treatment

Administration of recombinant tPA (rtPA, or trade name Alteplase®) is an FDA-approved therapy for acute ischemic stroke (AIS), but poses the risk of hemorrhagic complications. Recombinant tPA can be rapidly inactivated by the endogenous inhibitor, plasminogen activator inhibitor 1 (PAI-1). In this work, we study a novel treatment approach that combines a PAI-1 inhibitor, PAItrap4, with a reduced dose of rtPA to address the hemorrhagic concern of rtPA. PAItrap4 is a highly specific and very potent protein-based inhibitor of PAI-1, comprising of a variant of uPA serine protease domain, human serum albumin, and a cyclic RGD peptide. PAItrap4 efficiently targets and inhibits PAI-1 on activated platelets, and also possesses a long half-life in vivo. Our results demonstrate that PAItrap4 effectively counteracts the inhibitory effects of PAI-1 on rtPA, preserving rtPA activity based on amidolytic and clot lysis assays. In an in vivo murine stroke model, PAItrap4, together with low-dose rtPA, enhances the blood perfusion in the stroke-affected areas, reduces infarct size, and promotes neurological recovery in mice. Importantly, such treatment does not increase the amount of cerebral hemorrhage, thus reducing the risk of cerebral hemorrhage. In addition, PAItrap4 does not compromise the normal blood coagulation function in mice, demonstrating its safety as a therapeutic agent. These findings highlight this combination therapy as a promising alternative for the treatment of ischemic stroke, offering improved safety and efficacy.

Coagulation-monitored, dose-adjusted catheter-directed thrombolysis or pharmaco-mechanical thrombus removal in deep vein thrombosis.

Background: Pharmaco-mechanical thrombectomy (PMT) and catheter-directed thrombolysis (CDT) are therapeutic options for selected patients with acute deep vein thrombosis (DVT) to prevent post-thrombotic syndrome (PTS). Patients and methods: We aimed to describe the clinical characteristics and outcomes of 159 patients with symptomatic iliofemoral DVT undergoing PMT alone, CDT alone, or CDT followed by PMT (bail-out) in the Swiss Venous Stent Registry. The primary outcome was the incidence of peri-interventional major and minor bleeding complications (ISTH criteria). Secondary outcomes included the incidence of PTS and stent patency after 3 years. Results: Mean age was 49±20 years and 58% were women. DVT involved the iliac veins in 99% of patients, whereas 53% had an underlying iliac vein compression. PMT alone was used in 40 patients, CDT alone in 77, and 42 received initial CDT followed by bail-out PMT due to insufficient thrombus clearance. Single-session PMT was the preferred approach in patients with iliac vein compression, patent popliteal vein, and absence of IVC thrombus. Patients treated with PMT alone received a lower r-tPA dose (median 10 mg, IQR 10-10) vs. those treated with CDT (20 mg, IQR 10-30). The rate of peri-interventional major bleeding was 0%, 1%, and 2%, whereas that of minor bleeding was 0%, 1%, and 12%, respectively, all occurring during CDT. After 3 years, PTS occurred in 6%, 9%, and 7% of patients, respectively. The primary stent patency rate was 95%, 88%, and 83%, respectively. Conclusions: The use of PMT and CDT for iliofemoral DVT was overall safe and resulted in high long-term patency and treatment success. Given the less severe presentation of DVT, single-session PMT appeared to be characterized by numerically better primary patency and lower perioperative bleeding event rates than CDT.

EFFICACY AND SAFETY OF INTRAVENOUS THROMBOLYTIC THERAPY IN PATIENTS OVER EIGHTY YEARS

: Introduction: Intravenous thrombolytic therapy (IVTT) is licensed for patients under 80 years in many countries. In this study, we aimed to demonstrate functional results and complication rates of IVTT in patients over eighty years and whether there is a difference in efficacy and safety between low dose and standard dose recombinant tissue plasminogen activator (rTPA). Methods: A retrospective observational study of patients over eighty who admitted to Suleyman Demirel University Faculty of Medicine Hospital between August 2016 and April 2021 and to Isparta City Hospital between April 2017 and April 2021 and diagnosed with acute ischemic stroke were conducted. Third month modified rankin scores (mRS) and mortality rates of patients and hemorrhagic transformations were determined. Results: There were 29 patients in IVTT group and 25 patients in non-IVTT group. By the third month, it was observed that functional independence (mRS 0-2) ratio was increased more in IVTT group, but it wasn’t statistically significant (p: 0.087). In mortality and symptomatic intracerebral hemorrhage rates, there wasn't statistically significant diffirence between IVTT and non-IVTT groups and low dose and standard dose rTPA groups by the third month. Conclusion: The efficacy and complication rates of IVTT in patients over 80 years were found similar to not receive IVTT. These results support the safety of IVTT in patients over 80 years. In low or standard dose rTPA preference, we observed that there wasnt’ statistically significance in efficacy and safety. We believe that these results will be supported by studies with larger number of patients.

Comparison of Effectiveness and Safety of Low-Dose Versus Standard-Dose Intravenous Recombinant Tissue Plasminogen Activator in Patients With Acute Ischemic Stroke: A Meta-Analysis.

The aim of the present meta-analysis is to compare the efficacy and safety of low-dose and standard-doserecombinant tissue plasminogen activators (r-tPA) in patients with acute ischemic stroke. The present meta-analysis was conducted according to the Meta-Analysis of Observational Studies in Epidemiology (MOOSE)guidelines. We conducted a systematic search in PubMed, Embase, and the Cochrane Library to identify studies published between January 1, 2010, and January 31, 2023, using the following terms: "stroke," "alteplase," "doses," "efficacy," "tissue plasminogen activator," "r-tPA," and "safety."Primary efficacyoutcomes included favorable outcomes (Modified Rankin Scale scores of 0-2), while secondary efficacy outcome was all-cause mortality at 90 days. Safety outcomes included asymptomatic intracerebral hemorrhage (ICH)and symptomatic ICH assessed using the National Institute of Neurological Disorders and Stroke (NINDS) study and the Safe Implementation of Thrombolysis in Stroke-Monitoring (SITS-MOST) study. We also compared parenchymal hematomas as safety outcome between the two groups defined by the authors themselves in their research.A totalof 16 studies were included in the present meta-analysis. The meta-analysis did not report any significant difference between low-dose and standard-dose r-tPA in terms of mortality, symptomatic intracranial hemorrhage (SICH), asymptomatic ICH, and parenchymal hematomas. However, the favorable outcome was significantly greater in patients receiving a standard dose of r-tPA.

Analyses on safety and efficacy of non-standard dose of r-tPA in intravenous thrombolysis-treated AIS patients.

Intravenous 0.9 mg/kg recombinant tissue plasminogen activator (r-tPA) is one of the most effective treatments in acute ischemic stroke patients. Practically, the dose of r-tPA is still a topic that is constantly being discussed. For this observational study, data were obtained from 537 patients who received r-tPA thrombolysis at Shanghai Sixth People's Hospital stroke center over 5 years (2014-2019). Patients were divided into two groups: a non-standard dose group (0.6 mg/kg ≤ dose < 0.9 mg/kg) and a standard dose group (0.9 mg/kg). Different outcomes were observed: efficacy: 3 months mRS 0-1 (3m-mRS0-1); safety: symptomatic intracranial hemorrhage within 24 h (24h-sICH) and 3 months mortality (3m-death). We also observed the effect of r-tPA dose coefficient on outcomes in different age groups and baseline National Institute of Health stroke scale (NIHSS) score subgroups. There were 265 patients who gave the standard dose treatment and 272 gave the nonstandard dose. There was no significant difference between the non-standard dose group and the standard dose group in 3m-mRS0-1, 3m-death, and 24h-sICH (p = 0.567, 0.327, and 0.415, respectively). The dose coefficient presents a significant negative correlation (p = 0.034, B = -4.290) with 3m-death in NIHSS < 16 sub-group. Door-to-needle time (DNT) is the most important independent outcome-influential factor (MIOIF) in the NIHSS ≥16 sub-group. The diabetes history and baseline NIHSS score were the MIOIF in the age ≥80-year sub-group. The non-standard dose group (0.6 mg/kg ≤ dose < 0.9 mg/kg) shows no difference in safety and effectiveness than the standard dose group (0.9 mg/kg) in our study. The standard dose should be considered first according to current evidence and Guidelines, but the non-standard dose (0.6 mg/kg ≤ dose < 0.9 mg/kg) might be an option in the actual diagnosis and treatment process considering the patient's clinical profile and financial condition.

Sono-assisted-thrombolysis by three-dimensional diagnostic ultrasound improves epicardial recanalization and microvascular perfusion in acute myocardial infarction.

BackgroundThis study aimed to evaluate the multiple interactions between therapeutic ultrasound (TUS), microbubbles (MB), and recombinant tissue plasminogen activator (r-tPA) by using three-dimensional (3D) ultrasound to examine the impact of thrombolysis with r-tPA on epicardial recanalization and microcirculation in patients with acute ST-segment-elevation myocardial infarction (STEMI).MethodsAcute thrombotic occlusion of the left anterior descending (LAD) artery was induced in 32 Bama pigs, who were fed a high-cholesterol diet and randomized into four groups: (I) a 3D-sono-assisted-thrombolysis (3D/TUS + MB + r-tPA) group; (II) a 3D/TUS + MB group; (III) a full-dose r-tPA group; and (IV) a 3D/TUS alone group. Epicardial angiographic recanalization rate, microcirculation in the at-risk myocardium, ST-segment elevation on electrocardiogram, and changes in the at-risk myocardium and the myocardial infarct area were compared between the groups.ResultsAfter treatment, distal LAD recanalization was observed in 87.5% (7/8) of pigs in the 3D/TUS + MB + r-tPA group, which was significantly higher than the rates observed in the 3D/TUS + MB (37.5%) and the full-dose r-tPA (50.0%) groups (all P<0.05). The average acoustic intensity in the 3D/TUS + MB + r-tPA group (193.78±10.15 dB) was also significantly higher than that in the 3D/TUS + MB (154.29±31.94 dB) and the r-tPA (141.42±28.31 dB) groups (all P<0.05). The decrease in ST-segment elevation in the 3D/TUS + MB + r-tPA group (1.31±1.22 mm) was significantly higher than that in the 3D/TUS + MB (5.38±1.77 mm) and the r-tPA (4.30±2.08 mm) groups (all P<0.05). Furthermore, the ratio of the infarcted myocardial area divided by the at-risk myocardial area was markedly lower in the 3D/TUS + MB + r-tPA group (0.51±0.14) than in the 3D/TUS + MB (0.69±0.28) and r-tPA (0.75±0.23) groups (all P<0.05).ConclusionsThree-dimensional sono-assisted-thrombolysis directly improves infarct-related recanalization rates, enhances microcirculation, reduces r-tPA dosage, and ameliorates the thrombolytic effect of r-tPA in acute STEMI.

Intravenous thrombolysis with 0.65 mg/kg r-tPA may be optimal for Chinese mild-to-moderate stroke.

BackgroundIntravenous recombinant tissue plasminogen activator (r-tPA) with 0.9 mg/kg is the standard treatment for acute ischemic stroke, but it remains unclear whether it is optimal for all patients. We aimed to determine the optimal dose of r-tPA for Chinese stroke based on the data from the INTRECIS study.MethodsFrom the INTRECIS cohort, patients receiving intravenous r-tPA within 4.5 h of onset were included. According to r-tPA dose, patients were assigned into seven groups (from 0.60 to 0.90 mg/kg). The primary outcomes were the proportion of excellent functional outcomes and symptomatic intracranial hemorrhage.ResultsOverall, 2,666 patients were included: 156 in 0.60 mg/kg group, 117 in 0.65 mg/kg group, 127 in 0.70 mg/kg group, 188 in 0.75 mg/kg group, 154 in 0.80 mg/kg group, 359 in 0.85 mg/kg group, and 1,565 in 0.90 mg/kg group. After adjustment for baseline characteristics, only 0.65 mg/kg group had significantly higher proportion of excellent functional outcome than 0.90 mg/kg group (79.5 vs. 71.4%, odds ratio = 1.833, 95% CI = 1.006–3.341, adjusted p = 0.048). The subgroup analysis showed no evidence of differences in the odds of having a primary outcome between the two groups by age, admission NIHSS, onset to thrombolysis time, and TOAST classification. There was no significant difference in symptomatic intracranial hemorrhage between groups.ConclusionOur study presented the first evidence that intravenous thrombolysis with 0.65 mg/kg r-tPA may be optimal for Chinese mild-to-moderate stroke.Registrationhttps://www.clinicaltrials.gov, identifier: NCT 02854592.

The influence of unexpected early termination of intravenous rt-PA treatment on clinical outcome in acute ischemic stroke patients.

This study aimed to explore the impact of unexpected early termination during intravenous thrombolysis on clinical prognosis in patients with acute ischemic stroke (AIS). Patients who received intravenous thrombolysis were divided into an early termination group and a normal treatment group. The causes of unexpected termination were analyzed, and the prognosis was compared between the groups. The main causes of early termination of thrombolytic therapy included subjective wishes of family members (11.8%, 4) and persistently elevated blood pressure (14.7%, 5). The effective rate of thrombolytic therapy in the early termination group was significantly lower than that in the normal treatment group (P < 0.05). The rate of early neurological deterioration in the early termination group was significantly higher than that in the normal treatment group (P < 0.05). There was no significant difference in the incidence of symptomatic intracranial hemorrhage after thrombolysis between the two groups (P > 0.05). The average mRS score of the early termination group was significantly higher than that of the normal treatment group (P < 0.05). Multivariate analysis indicated that early termination of thrombolytic therapy and cumulative dosage of rt-PA before termination were the main factors affecting the 3-month prognosis. Subjective wishes of family members and persistently elevated blood pressure may be the main causes of early termination of thrombolysis, and the 3-month prognosis of patients could be adversely affected by early termination of thrombolytic therapy and cumulative dosage of rt-PA. Certain measures, such as popularizing thrombolytic health education and optimizing blood pressure management before and during thrombolysis, may be helpful for the normal operation of intravenous thrombolysis.

Safety and efficacy of low-dose rt-PA with tirofiban to treat acute non-cardiogenic stroke: a single-center randomized controlled study

Background and purposeThe recanalization rate after intravenous thrombolysis (IVT) is not enough and there is still the possibility of re-occlusion. We aim to investigate the effectiveness and safety of infusing tirofiban after IVT.MethodsWe performed a prospective controlled study of 60 patients with acute non-cardiogenic ischemic stroke who were hospitalized in Yantai Yuhuangding Hospital from January 2018 to December 2019. The patients were divided into 2 groups: those who received tirofiban for 24 h after IVT (rt-PA + T group) and those who did not receive postprocedural intravenous tirofiban (rt-PA group). The rt-PA + T group received low-dose rt-PA (0.6 mg/kg). The rt-PA group received standard dose rt-PA (0.9 mg/kg). The main outcome measure were safety, included the symptomatic intracranial hemorrhage (sICH), any ICH, severe systemic bleeding, and mortality. The secondary outcome measure is curative efficacy which were evaluated by the 7d-NIHSS score and functional outcomes at 90 days. During hospitalization, the deterioration of neurological function was recorded.ResultsAll patients completed the follow-up with complete data, there were 30 patients in each of groups. The general characteristics between the two group patients had no statistically significant differences. Compared with the rt-PA + T group and the rt-PA group, in terms of safety, the rates of the sICH, severe systemic bleeding, and mortality in both groups were 0, and there was no statistically significant difference in the rates of any ICH between the two groups (10.0% vs. 3.3%, P = 0.306). In terms of efficacy, the rate of the early neurological deterioration events (END) was no statistical significance (0 vs. 6.6%, P = 0.246). There was no significant difference in the NIHSS score between the two groups before the IVT, and also at 24 h, however, the 7d-NIHSS score was lower in the rt-PA + T group compared with the rt-PA group (2.33 ± 1.85 vs. 4.80 ± 4.02, P = 0.004). At 90 days, 83.3% of patients in the rt-PA + T group had favorable functional outcomes compared with 60.0% of patients in the rt-PA group (P = 0.045).ConclusionsLow-dose rt-PA combined with tirofiban in acute non-cardiogenic ischemic stroke did not increase the risk of ICH, and mortality, and it was associated with neurological improvement.Trial RegistrationThe trial has been registered at the ChiCTR and identified as ChiCTR1800014666 (28/01/2018).

Effect of the interaction between atrial fibrillation and rt-PA dose on the prognosis of acute ischaemic stroke with intravenous thrombolysis

BackgroundThe association between atrial fibrillation (AF) and the prognosis of acute ischaemic stroke (AIS) remains controversial; whether the recombinant tissue plasminogen activator dose influences this association remains poorly understood.MethodsPatients who...

Effect of the interaction between atrial fibrillation and rt-PA dose on the prognosis of acute ischaemic stroke with intravenous thrombolysis.

The association between atrial fibrillation (AF) and the prognosis of acute ischaemic stroke (AIS) remains controversial; whether the recombinant tissue plasminogen activator dose influences this association remains poorly understood. Patients who had an AIS were enrolled from eight stroke centres in China. According to the recombinant tissue plasminogen activator dose, patients treated with intravenous recombinant tissue plasminogen activator within 4.5 hours after symptom onset were divided into a low-dose group (recombinant tissue plasminogen activator <0.85 mg/kg) and a standard-dose group (recombinant tissue plasminogen activator ≥0.85 mg/kg). Patients who had an AIS in the low-dose group and the standard dose group were divided into whether or not they had AF. The main outcomes were major disability (modified Rankin scale (mRS) score 3-5), mortality and vascular events occurring within 3 months. The study included 630 patients who received recombinant tissue plasminogen activator after AIS, including 391 males and 239 females, with a mean age of 65.8 years. Of these patients, 305 (48.4%) received low-dose recombinant tissue plasminogen activator and 325 (51.6%) received standard dose recombinant tissue plasminogen activator. The recombinant tissue plasminogen activator dose significantly influenced the association between AF and death or major disability (p-interaction=0.036). After multivariate adjustment, AF was associated with an increased risk of death or major disability (OR 2.90, 95% CI 1.47 to 5.72, p=0.002), major disability (OR 1.93, 95% CI 1.04 to 3.59, p=0.038) and vascular events (HR 5.01, 95% CI 2.25 to 11.14, p<0.001) within 3 months in patients with standard-dose recombinant tissue plasminogen activator. No significant association was found between AF and any clinical outcome in patients with low-dose recombinant tissue plasminogen activator (all p>0.05). With AF, the mRS score distribution showed a significantly worse shift in patients with standard-dose recombinant tissue plasminogen activator (p=0.016) than in those with low-dose recombinant tissue plasminogen activator (p=0.874). AF may be a strong predictor of poor prognosis in patients who had an AIS receiving standard-dose recombinant tissue plasminogen activator, suggesting that low-dose recombinant tissue plasminogen activator should be administered to patients who had a stroke with AF to improve their prognosis.

Safety and efficacy of a new modified intravenous recombinant tissue plasminogen activator (rt-PA) regimen in Chinese patients with acute ischemic stroke: A descriptive retrospective cohort study with subgroup-analysis of different rt-PA dose

Evidence for effects of the dose of recombinant tissue plasminogen activator(rt-PA) in Asian populations is inconclusive. The standard dose may cause drug waste and increase economic burden in developing country. Therefore, we preliminarily describe the safety and efficacy of a new modified dose of rt-PA regimen(0.6 or 0.9 mg/kg, with a maximum dose of 50 mg) in real world settings. 265 consecutive patients with ischemic stroke were treated with intravenous(IV) rt-PA alone from all the 323 consecutive patients treated with reperfusion therapy between January 1, 2017 and March 31, 2020. Safety and Efficacy was assessed by early neurological improvement(ENI), early neurological deterioration(END), symptomatic intracranial hemorrhage(sICH) and 90-day outcome defined by modified Rankin scale(mRS). Subgroup analysis was conducted to draw comparisons between different dose groups ([0.5,0.6)mg/kg, [0.6,0.7)mg/kg, [0.7,0.8)mg/kg, [0.8,0.9]mg/kg). Among the 265 patients, 150(56.60%) had a favorable outcome at 3 months(3 M); Mortality occurred in 17(6.40%) in 3 M; sICH in 12(4.50%); ENI in 70(26.40%); END2 in 29(10.90%) and END4 in 18(6.80%). In subgroup analysis, there was a significant difference in sICH that more patients developed sICH in [0.8–0.9]mg/kg group(P = 0.044) in univariate analysis of different dose. After adjusting, there was no significant difference between 4 dosage groups. Significant differences were seen in gender, atrial fibrillation and baseline NIHSS in the multivariable model of favorable outcome at 3 M. Our study preliminarily shows a good safety and efficacy of our modified rt-PA regimen, indicating that this regimen should be worthy of further study especially in developing country to reduce the financial burden of patients and avoid drug waste.

P269 LOCAL ULTRASOUND–FACILITATED THROMBOLYSIS IN ACUTE PULMONARY EMBOLISM: HAS A SPACE?

Abstract Acute pulmonary embolism (PE) has an annual incidence of 48 patients per 100,000 with a mortality rate of 10%, few hours after the onset of symptoms. The use of full dose of thrombolytic agent is currently the treatment of choice in acute PE at intermediate and high risk, although its contraindications are well known. An alternative choice is delivered, via percutaneous femoral or jugular venous access, infusion catheters in the pulmonary artery (PA), in order to perform a local thrombolysis (based on a map of thrombus distribution observed at pulmonary CT), with a lower dose of trobolytic agent (rTPA) in a limited time, with a core for emission of ultrasound waves capable of breaking the mesh of the thrombus. Data from the KNOCOUT PE registry show a reduced frequency of fatal intracranial hemorrhage (ICH 2.5%), compared with the full dose of rTPA. Since February 2021 we have treated 7 patients with PE, all with cTnI, D–dimer and high NT–ProBNP and with pulmonary CT finding of large thrombus burden with pruning of peripheral pulmonary branches compatible with the diagnosis of PE at high and intermediate risk in patients with complex comorbidities (significant PESI and simplified PESI). On admission to the ICU all patients were with BP &amp;lt; 100 mmHg, RR &amp;gt; 20/min, satO2 &amp;lt; 90% and HR &amp;gt; 100 bpm. In echocardiogram all were with impaired RV (RV/LF ratio &amp;gt;1 and TAPSE &amp;lt;15mm). All patients was treated with UHF, 1 in fondaparinux for thrombocytopenia. At time between 4h and 8gg from the onset of symptoms, all patients underwent placement of 1 or 2 catheters in right and/or left PA, 106 cm and 135 cm length with zone of interest between 18/32 cm. When possible, hemodynamic parameters were evaluated: PAPm, cardiac output, and stroke volume to characterize the associated hemodynamic deterioration. 12mg of rtPA per catheter was administered over 12 hours. In 3 patients an echocardiogram was performed at 6 hours. In all at 24 hours, vital and laboratory parameters were measured, and in one patient, right heart catheterization was repeated. In no patient was treatment discontinued early, nor were ICH or minor bleeding recorded. Low dose of rtPA allowed use of the technique in patients with severe comorbidities at the limit of thrombolysis use, in the presence of marked RV distress and severe hemodynamic instability. Trials are in progress to shorten the time and therefore reduce the dose of rTPA with equal effectiveness on the clinical course of acute PE.

Injection of Recombinant Tissue Plasminogen Activator into Extracorporeal Membrane Oxygenators Postpones Oxygenator Exchange in COVID-19.

Coronavirus disease 2019 (COVID-19) has drastically increased the number of patients requiring extracorporeal life support. We investigate the efficacy and safety of low-dose recombinant tissue-type plasminogen activator (rtPA) injection into exhausted oxygenators to delay exchange in critically ill COVID-19 patients on veno-venous extracorporeal membrane oxygenation (V-V ECMO). Small doses of rtPA were injected directly into the draining section of a V-V ECMO circuit. We compared transmembrane pressure gradient, pump head efficiency, membrane arterial partial oxygen pressure, and membrane arterial partial carbon dioxide pressure before and after the procedure. Bleeding was compared with a matched control group of 20 COVID-19 patients on V-V ECMO receiving standard anticoagulation. Four patients received 16 oxygenator instillations with rtPA at 5, 10, or 20 mg per dose. Administration of rtPA significantly reduced transmembrane pressure gradient (Δ pm = 54.8 ± 18.1 mmHg before vs . 38.3 ± 13.3 mmHg after, p < 0.001) in a dose-dependent manner (Pearson's R -0.63, p = 0.023), allowing to delay oxygenator exchange, thus reducing the overall number of consumed oxygenators. rtPA increased blood flow efficiency η (1.20 ± 0.28 ml/revolution before vs . 1.24 ± 0.27 ml/r, p = 0.002). Lysis did not affect membrane blood gases or systemic coagulation. Minor bleeding occurred in 2 of 4 patients (50%) receiving oxygenator lysis as well as 19 of 20 control patients (95%). Lysis of ECMO oxygenators effectively delays oxygenator exchange, if exchange is indicated by an increase in transmembrane pressure gradient. Application of lysis did not result in higher bleeding incidences compared with anticoagulated patients on V-V ECMO for COVID-19.

AngioJet Rheolytic Thrombectomy to Treat Inferior Vena Cava Filter-Related Thrombosis: Efficacy and Safety Compared With Large-Lumen Catheter Suction.

ObjectiveTo compare the efficacy and safety of AngioJet rheolytic thrombectomy (ART) and large-lumen catheter suction (LCS) in the treatment of inferior vena cava (IVC) filter related IVC-iliac vein thrombosis.MethodsThe clinical data and medical imaging materials of 65 cases were collected, which suffered acute inferior vena cava filter related IVC-iliac vein thrombosis and received percutaneous mechanic thrombectomy (PMT) from June 2016 to June 2020 in our center, including 32 cases of LCS group and 33 cases of ART group. The final thrombolysis rate, the incidence of complications, and the follow-up are evaluated.ResultsThe limb swelling was significantly relieved in patients with PMT after treatment. The peri-diameter difference of the limb in the LCS group before and after treatment was [(5.20 ± 2.03) vs. (2.17 ± 1.29) cm, P < 0.05], and that in the ART group before and after treatment was [(4.79 ± 2.23) vs. (1.74 ± 0.94) cm, P < 0.05]. The amount of postoperative recombinant tissue-type plasminogen activator (rt-PA) is reduced in ART group [(57.97 ± 21.25) in LCS group vs. (40.45 ± 20.89) mg in ART group, P < 0.05], and the thrombolysis rate was higher than that of the LCS group [(74.13 ± 19.74% in LCS group) vs. (84.58 ± 11.90% in ART group %), P < 0.05]. No serious complications occurred during the treatment.ConclusionBoth LCS group and ART group have good thrombosis clearance effects on the inferior vena cava filter related IVC-iliac vein thrombosis. ART can reduce the rt-PA dose, increase the thrombolysis rate and reduce the risk of bleeding during thrombolysis.

Safety and efficacy of tenecteplase versus alteplase in patients with acute ischaemic stroke (TRACE): a multicentre, randomised, open label, blinded-endpoint (PROBE) controlled phase II study

BackgroundTenecteplase (TNK) possesses several pharmacological characteristics superior to conventional alteplase (rt-PA), with well-established safety and efficacy profile in Caucasians. There exists controversy over the optimal dose of intravenous rt-PA for...