Low-dose thrombolysis for submassive pulmonary embolism

The role of thrombolysis in submassive pulmonary embolism (PE) is controversial due to the high risk of hemorrhage. This study aimed to evaluate the role of half-dose tissue-type plasminogen activator (rt-PA) in preventing death/hemodynamic decompensation in submassive (intermediate-risk) PE without increasing the risk of bleeding. In a prospective, non-randomized, open-label, single-center trial, we compared 50 mg rt-PA plus low molecular weight heparin (LMWH) with LMWH in submassive (intermediate-risk) PE. Eligible cases had confirmed pulmonary hypertension on echocardiography, and/or right ventricular cavity expansion and/or interventricular septal deviation on echocardiography, and/or right to left ventricular ratio equal to or greater than 0.9 mm on CT angiography. The primary outcome was death or hemodynamic decompensation within 7 and 30 days after treatment was given. The primary safety outcome was major extracranial bleeding or hemorrhagic stroke within 7 days. Seventy-six patients were included in the study. Total death/hemodynamic decompensation in the first 7 and 30 days was significantly less in the half-dose rt-PA group than in the LMWH group (p=0.028 and p=0.009, respectively). No significant differences were found between the two groups in terms of recurrent embolism and pulmonary hypertension at 6-month follow-up (p=1.000 and p=0.778). There was no intracranial hemorrhage in any of the patients. There were no statistically significant differences between the two groups in terms of major or minor bleeding complications. This trial showed half-dose rt-PA treatment in submassive (intermediate-risk) PE prevented death/hemodynamic decompensation in the first 7-day and 30-day period compared with LMWH treatment without increasing the risk of bleeding.

Accelerated treatment with rtPA for pulmonary embolism induced circulatory arrest

Patients with circulatory arrest due to pulmonary embolism (PE) should be treated with fibrinolytics. Current guidelines do not specify which regimen to apply, and it has been suggested that the regimen of 100 mg rtPA/2 h should be used, because this is recommended for hemodynamic instable PE in the ESC/ERS Guideline. This two hour regimen, however, is incompatible with key principles of cardiopulmonary resuscitation (CPR), such as employment of interventions that allow fast evaluation of effectiveness, and limitation of the total duration of CPR to avoid poor neurological outcomes. Additionally, the low flow-state during CPR has important consequences for the pharmacokinetic properties of rtPA. Arguably, the volume of distribution is lower, the metabolism reduced and the half life time longer. Therefore, these changes largely discard the rationale to use high dosages of rtPA over a prolonged period of time. More importantly, these changes highlight that the guideline recommendations, based on studies in patients without circulatory arrest, cannot be easily translated to the situation of circulatory arrest. An accelerated regimen of rtPA (0.6 mg/kg/15 min., max 50 mg) is mentioned by the 2019 ESC/ERS Guideline. However, empirical support or a rationale is not provided. Due to the rarity of the situation and ethical difficulties associated with randomizing unconscious patients, a randomized head-to-head comparison between the two regimens is unlikely to ever be performed. With this comprehensive overview of the pharmacokinetics of rtPA and current literature, a strong rationale is provided that the accelerated protocol is the regimen of choice for patients with PE-induced circulatory arrest.

Long-term results of low-dose tissue plasminogen activator therapy in acute pulmonary embolism

Recombinant tissue plasminogen activator (rt-PA) is the most commonly used thrombolytic agent in patients with high risk and intermediate to high mortality risk acute pulmonary embolism (PE). Clinical trials have shown early efficacy and safety of low-dose rt-PA. This study investigated the effects of low-dose rt-PA treatment on acute PE in long-term prognosis, recurrence of pulmonary thromboembolism, or the development of late complications. In this study, 48 patients undergoing low-dose rt-PA for the relative contraindications of thrombolytic therapy and 48 patients undergoing standard-dose therapy were evaluated retrospectively. Long-term follow-up investigated the chronic PE, recurrence, and causes of morbidity and mortality.

In both treatment groups, embolism-induced mortality and overall mortality rates were similar in the first 30 days (p=1.000, p=0.714, respectively). Overall mortality rates in long-term follow-up were 41.7% in the low-dose treatment group and 16.7% in the standard-dose treatment group (p=0.013). The mortality rate at the first year was higher in the low-dose-treated group (p=0.011) and most of the deaths were due to accompanying comorbidities. There was no difference in PE recurrence and duration of recurrence between the groups (p=0.598, p=0.073, respectively). Intracranial hemorrhage due to therapy developed in one patient in both groups.

Low-dose thrombolytic therapy in acute PE reduces PE-related mortality in the early period. Long-term follow-up showed that thrombolytic therapy did not affect mortality rates independently of the dose and PE recurrence.

Retrospective comparison of ultrasound facilitated catheter-directed thrombolysis and systemically administered half-dose thrombolysis in treatment of pulmonary embolism

This study retrospectively compared the outcomes of patients who received ultrasound facilitated catheter-directed thrombolysis (UFCDT) versus systemically administered ‘half-dose’ thrombolysis (HDT) in 97 patients with PE. The outcomes assessed included changes in baseline pulmonary artery systolic pressure (PASP), right ventricle/left ventricle ratio (RV/LV), cost and duration of hospitalization, death, bleeding, and recurrent venous thromboembolism in the short and intermediate term follow-up. Analyses were performed using a covariance adjustment propensity score approach to address baseline differences between groups in variables associated with PASP and RV/LV, covarying baseline scores. The baseline mean ± SE PASP dropped from 49.3 ± 1.1 to 32.5 ± 0.3 mmHg at 36 hours in the HDT group, and from 50.6 ± 1.2 to 35.1 ± 0.4 mmHg in the UFCDT group; group × time interaction p-value = 0.007. Corresponding drops in the RV/LV were from a baseline of 1.26 ± 0.05 to 1.07 ± 0.01 in the HDT group and from 1.30 ± 0.05 to 1.14 ± 0.01 in the UFCDT group at 36 hours; group × time interaction p-value = 0.269. Statistically significant decreases were noted in PASP and RV/LV for both the HDT and UFCDT at 36 hours and follow-up. PASP through follow-up was significantly lower in the HDT than the UFCDT group. Likewise, RV/LV was lower in the HDT group. The duration and cost of hospitalization were lower in the HDT group (6.2 ± 1.4 days vs 1.9 ± 0.3 days, p < 0.001; US$12,000 ± $3000 vs $74,000 ± $6000, p < 0.001). We conclude that both UFCDT and HDT lead to rapid reduction of PASP and RV/LV, whereas HDT leads to a lower duration and cost of hospitalization.

Clinical efficacy of low dose recombinant tissue-type plasminogen activator for the treatment of acute intermediate-risk pulmonary embolism

OBJECTIVES

To investigate the efficacy and safety of initial thrombolysis by recombinant tissue-type plasminogen activator (rt-PA) in compared with anticoagulant therapy in patients with acute intermediate-risk pulmonary embolism (PE).  Methods: Sixty-six patients with acute intermediate-risk PE were randomly assigned to receive rt-PA or LMWH between June 2014 and June 2017 in our department. We obtained information regarding the difference in the right ventricle/left ventricle (RV/LV) ratio, pulmonary artery systolic pressure (PASP), clinical symptoms improvement, PE-related mortality, hemodynamic decompensation, recurrent PE, and major and minor bleeding.  Results: In the rt-PA group, the mean PASP was reduced from 52.0±12.2 at baseline to 34.8±9.4 (p less than 0.001) and the mean RV/LV ratio was reduced from 1.26±0.22 at baseline to 0.96±0.18 (p less than 0.001) at 24 hours. In the LMWH group, the mean PASP was 53.4±12.8 at baseline and 48.5±11.9 at 24 hours (p=0.11), and the mean RV/LV ratio was 1.22±0.19 at baseline and 1.17±0.21 at 24 hours (p=0.31). In comparison with the LMWH group, there was a significant reduction in PASP and an improvement in the symptom severity in the rt-PA group. At 90 days, there was no difference in mortality, recurrent venous thromboembolism and major bleeding as a safety outcome, but increased minor bleeding and decreased hemodynamic decompensation occurred in the rt-PA group. Conclusions: In patients with acute intermediate-risk PE, low dose thrombolytic therapy is considered safe and effective, it can be recommended as an alternative option in clinical treatment.

Efficacy and safety of recombinant tissue plasminogen activator for venous thrombosis after paediatric heart surgery

OBJECTIVE

Reports in the literature of treatment with recombinant tissue plasminogen activator following cardiac surgery are limited. We reviewed our experience to provide a case series of the therapeutic use of tissue plasminogen activator for the treatment of venous thrombosis in children after cardiac surgery. The data describe the morbidity, mortality, and clinical outcomes of tissue plasminogen activator administration for treatment of venous thrombosis in children following cardiac surgery.

DESIGN

The study was designed as a retrospective case series.

SETTING

The study was carried out in a 25-bed cardiac intensive care unit in an academic, free-standing paediatric hospital. Patients All children who received tissue plasminogen activator for venous thrombosis within 60 days of cardiac surgery, a total of 13 patients, were included. Interventions Data was collected, collated, and analysed as a part of the interventions of this study. Measurements and main results Patients treated with tissue plasminogen activator were principally young infants (median 0.2, IQR 0.07-0.58 years) who had recently (22, IQR 12.5-27.3 days) undergone cardiac surgery. Hospital mortality was high in this patient group (38%), but there was no mortality attributable to tissue plasminogen activator administration, occurring within <72 hours. There was one major haemorrhagic complication that may be attributable to tissue plasminogen activator. Complete or partial resolution of venous thrombosis was confirmed using imaging in 10 of 13 patients (77%), and tissue plasminogen activator administration was associated with resolution of chylous drainage, with no drainage through chest tubes, at 10 days after tissue plasminogen activator treatment in seven of nine patients who had upper-compartment venous thrombosis-associated chylothorax.

CONCLUSIONS

On the basis of our experience with administration of tissue plasminogen activator in children after cardiac surgery, tissue plasminogen activator is both safe and effective for resolution of venous thrombosis in this high-risk population.

Comparison of long-term outcomes of 50 and 100 mg rt-PA in the management of acute pulmonary thromboembolism

BACKGROUND

Pulmonary thromboembolism (PTE) is a life-threatening disease. In this study, we aimed to evaluate long-term outcomes of the use of 50 mg recombinant tissue-type plasminogen activator (rt-PA) in the management of PTE in terms of relapse, pulmonary hypertension (PH), mortality and hemorrhage and to compare with the use of 100 mg rt-PA.

METHODS

The study was designed as a retrospective cohort. Patients who were diagnosed as acute PTE and received either 50 or 100 mg rt-PA in a tertiary care hospital between 2010 and 2015 were included in the study. Rates of relapse, PH, mortality (in-hospital and long-term) and hemorrhage (major and minor) were calculated for each treatment group.

RESULTS

A total 117 patients, 73 females and 44 males, were evaluated. Eighty-three patients were administered 100 mg rt-PA, and 34 were administered 50 mg rt-PA. The mean age was lower in the 100 mg group compared to the 50 mg group (61 ± 15 vs 69 ± 14 years). There was a significant decrease in PH in each group at 3 months follow-up (P < .001). Although statistically nonsignificant, the relapse rate was lower in the 50 mg rt-PA group, but the 5-year mortality rate was higher in 50 mg rt-PA group (35.2% vs 27.7%, P = .50). Mortality was associated with older age and presence of malignancy.

CONCLUSIONS

Our results suggest that both doses of rt-PA have similar efficacy. The high mortality rate in the 50 mg group may have resulted from patient selection.

Lower dosage of recombinant tissue-type plasminogen activator (rt-PA) in the treatment of acute pulmonary embolism: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

According to US Food and Drugs Administration (FDA), 2 hour recombinant tissue plasminogen activator (rt-PA) 100mg infusion is recommended for eligible patients with acute pulmonary embolism (PE). However,there exists evidence implying that a lower dosage of rt-PA can be equally effective but potentially safer compared with rt-PA 100mg regimen. The aim of this systematic review and meta-analysis is to assess the efficacy and safety of low dose rt-PA in the treatment of acute PE.

MATERIAL AND METHOD

We searched Pubmed, EMBASE, the Cochrane library and CBM Literature Database for randomized controlled trials (RCT) focusing on low dose rt-PA for acute PE. Outcomes were described in terms of changes of image tests and echocardiography, major bleeding events, all-cause death, and recurrence of PE.

RESULTS

Five studies (440 patients) were included, three of which compared low dose rt-PA (0.6 mg/kg, maximum 50mg or 50mg infusion 2h) with standard dose (100mg infusion 2h). There were more major bleeding events in standard dose rt-PA group than in low dose group (OR 0.33, 95%CI 0.12-0.91;P=0.94,I(2)=0%), while there were no statistical differences in recurrent PE or all cause mortality between these two groups. Two studies compared low dose (0.6 mg/kg, maximum 50mg/2 min bolus or 10mg bolus, ≤40 mg/2 h) with heparin. There was no significant difference in major bleeding events (OR 0.73, 95% CI 0.14-3.98;P=0.72), recurrent PE or all cause mortality. No dose-related heterogeneity was found for all the included studies.

CONCLUSIONS

The results of this meta-analysis were hypothesis-generating. Based on the limited data, our systematic review suggested that low dose rt-PA had similar efficacy but was safer than standard dose of rt-PA. In addition, compared with heparin, low dose rt-PA didn't increase the risk of major bleeding for eligible PE patients.