Efficacy of alteplase thrombolysis for ED treatment of pulmonary embolism with shock

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.

Half-Dose Versus Full-Dose Alteplase for Treatment of Pulmonary Embolism

OBJECTIVES

Recent evidence suggests that half-dose thrombolysis for pulmonary embolism may provide similar efficacy with reduced bleeding risk compared with full-dose therapy, but comparative studies are lacking. We aimed to evaluate the effectiveness and safety of half-dose versus full-dose alteplase for treatment of pulmonary embolism.

DESIGN

A retrospective cohort study comparing outcomes in patients receiving half-dose (50 mg) versus full-dose (100 mg) alteplase for pulmonary embolism. We used propensity score matching and sensitivity analyses to address confounding and hospital-level clustering.

SETTING

Data from 420 hospitals obtained from the Premier Healthcare Database between January 2010 and December 2014.

SUBJECTS

Adult critically ill patients with acute pulmonary embolism treated with IV alteplase therapy.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

This study included 3,768 patients: 699 (18.6%) in the half-dose and 3,069 (81.4%) in the full-dose group. At baseline, patients receiving half-dose alteplase required vasopressor therapy (23.3% vs 39.4%; p < 0.01) and invasive ventilation (14.3% vs 28.5%; p < 0.01) less often, compared with full dose. After propensity matching (n = 548 per group), half-dose alteplase was associated with increased treatment escalation (53.8% vs 41.4%; p < 0.01), driven mostly by secondary thrombolysis (25.9% vs 7.3%; p < 0.01) and catheter thrombus fragmentation (14.2% vs 3.8%; p < 0.01). Hospital mortality was similar (13% vs 15%; p = 0.3). There was no difference in cerebral hemorrhage (0.5% vs 0.4%; p = 0.67), gastrointestinal bleeding (1.6% vs 1.6%; p = 0.99), acute blood loss anemia (6.9% vs 4.6%; p = 0.11), use of blood products (p > 0.05 for all), or documented fibrinolytic adverse events (2.6% vs 2.8%; p = 0.82).

CONCLUSIONS

Compared with full-dose alteplase, half-dose was associated with similar mortality and rates of major bleeding. Treatment escalation occurred more often in half-dose-treated patients. These results question whether half-dose alteplase provides similar efficacy with improved safety, and highlights the need for further study before use of half-dose alteplase therapy can be routinely recommended in patients with pulmonary embolism.

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.

Pulmonary embolism with cardiac arrest: a STEMI patient's unexpected course

We describe the successful use and complications of bolus-dose alteplase to treat strongly suspected pulmonary embolism (PE) with cardiac arrest in a patient initially presenting as ST-elevation myocardial infarcation (MI). Case description is followed by a review of the indications, safety, and dosing of systemic thrombolytic therapy for high-risk PE in the emergency department (ED). Diagnostic and therapeutic approach to PE in critically ill patients is also considered, including the potential utility of point-of-care ultrasound (PoCUS) in the ED.

Pulseless electrical activity in pulmonary embolism treated with thrombolysis (from the "PEAPETT" study)

OBJECTIVE

Pulseless electrical activity (PEA) during cardiac arrest portends a poor prognosis. There is a paucity of data in the use of thrombolytic therapy in PEA and cardiopulmonary arrest due to confirmed pulmonary embolism (PE). We evaluated the outcome of low-dose systemic thrombolysis with tissue plasminogen activator (tPA) in patients presenting with PEA due to PE.

METHODS

During a 34-month period, we treated 23 patients with PEA and cardiopulmonary arrest due to confirmed massive PE. All patients received 50 mg of tPA as intravenous push in 1 minute while cardiopulmonary resuscitation was ongoing. The time from initiation of cardiopulmonary resuscitation to administration of tPA was 6.5 ± 2.1 minutes.

RESULTS

Return of spontaneous circulation occurred in 2 to 15 minutes after tPA administration in all but 1 patient. There was no minor or major bleeding despite chest compression. Of the 23 patients, 2 died in the hospital, and at 22 ± 3 months of follow-up, 20 patients (87%) were still alive. The right ventricular/left ventricular ratio and pulmonary artery systolic pressure dropped from 1.79 ± 0.27 and 58.10 ± 7.99 mm Hg on admission to 1.16 ± 0.13 and 40.25 ± 4.33 mm Hg within 48 hours, respectively (P< .001 for both comparisons). There was no recurrent venous thromboembolism or bleeding during hospitalization or at follow-up.

CONCLUSION

Rapid administration of 50 mg of tPA is safe and effective in restoration of spontaneous circulation in PEA due to massive PE leading to enhanced survival and significant reduction in pulmonary artery pressures.

Low-Dose Systemic Alteplase (tPA) for the Treatment of Pulmonary Embolism

OBJECTIVE

To review and evaluate the evidence regarding the use of low-dose regimens of alteplase (tPA) for the treatment of pulmonary embolism (PE).

DATA SOURCES

A PubMed search (1966-January 2015) was conducted using the search terms pulmonary embolism, drug therapy, thrombolytic therapy, fibrinolytic agents, and tissue plasminogen activator. Articles were cross-referenced for additional citations.

STUDY SELECTION AND DATA EXTRACTION

Clinical trials and case reports published in the English language assessing the use of low-dose systemic tPA for the treatment of PE were reviewed for inclusion.

DATA SYNTHESIS

tPA is a thrombolytic agent indicated for the treatment of massive and submassive PE. Major bleeding complications of tPA are dose dependent and may occur in up to 6.4% of patients. Clinical trials have demonstrated safety and efficacy of low-dose tPA, particularly showing its benefit in patients with a low body weight (<65 kg) and right-ventricular dysfunction. Furthermore, case reports have safely used lower doses of tPA in patients at higher risk of bleeding, including elderly, pregnant, and surgical patients.

CONCLUSIONS

The available data suggest that low-dose tPA may be a safe and effective treatment option for acute PE, particularly in patients at a high risk of bleeding. More studies are needed to determine the optimal dosing regimen of tPA for PE.

Systemic thrombolysis for acute pulmonary embolism

Acute pulmonary embolism is a frequent cause of hospitalization and is associated with a wide range of symptom severity. Anticoagulants are the mainstay of treatment for acute pulmonary embolism; however, in patients with massive or submassive pulmonary embolism, advanced therapy with thrombolytics may be considered. The decision to use thrombolytic therapy for acute pulmonary embolism should be based on careful risk-benefit analysis for each patient, including risk of morbidity and mortality associated with the embolism and risk of bleeding associated with the thrombolytic. Alteplase is currently the thrombolytic agent most studied and with the most clinical experience for this indication, although the most appropriate dose remains controversial, especially in patients with low body weight. When considering thrombolysis, unfractionated heparin is the preferred initial anticoagulant due to its short duration of action and its reversibility should bleeding occur.

Evidence-based diagnosis and thrombolytic treatment of cardiac arrest or periarrest due to suspected pulmonary embolism

When a previously healthy adult experiences atraumatic cardiac arrest, providers must quickly identify the etiology and implement potentially lifesaving interventions such as advanced cardiac life support. A subset of these patients develop cardiac arrest or periarrest due to pulmonary embolism (PE). For these patients, an early, presumptive diagnosis of PE is critical in this patient population because administration of thrombolytic therapy may significantly improve outcomes. This article reviews thrombolysis as a potential treatment option for patients in cardiac arrest or periarrest due to presumed PE, identifies features associated with a high incidence of PE, evaluates thrombolytic agents, and systemically reviews trials evaluating thrombolytics in cardiac arrest or periarrest. Despite potentially improved outcomes with thrombolytic therapy, this intervention is not without risks. Patients exposed to thrombolytics may experience major bleeding events, with the most devastating complication usually being intracranial hemorrhage. To optimize the risk-benefit ratio of thrombolytics for treatment of cardiac arrest due to PE, the clinician must correctly identify patients with a high likelihood of PE and must also select an appropriate thrombolytic agent and dosing protocol.

Alteplase treatment of acute pulmonary embolism in the intensive care unit

Acute pulmonary embolism accounts for 50 000 to 100 000 deaths each year in the United States. Because of the wide spectrum of clinical manifestations, ranging from massive pulmonary embolism to small peripheral emboli, stratifying and treating patients according to their signs and symptoms is important when an acute embolism is suspected. Patients' clinical findings can range from no signs or symptoms to unstable hemodynamic status and shock. The 3-month mortality is 10% to 15%, but can be as high as 60% in patients with hemodynamic shock. This article reviews the classifications of acute peripheral emboli, explains the treatment of acute peripheral emboli, reviews the pharmacology of alteplase, and presents an assessment of the literature evaluating alteplase for the treatment of acute peripheral emboli. Clinical pearls for the administration, monitoring, and care of a patient receiving alteplase in an intensive care unit also are discussed.

All contraindications to thrombolysis for life-threatening pulmonary embolus should be considered relative

Acute massive pulmonary embolism (PE) can be fatal; however, timely thrombolytic therapy can be life saving. Guidelines advocate the use of thrombolysis for massive PE in patients with an acceptable bleeding-risk profile. Nonetheless, estimating what constitutes an acceptable bleeding risk in those with life-threatening PE is a clinical challenge, and even contraindications considered 'absolute' may present lesser risk than leaving PE untreated. We discuss the case of a 77-year-old man who received thrombolysis for a massive PE 4 weeks following admission with a significant intracerebral bleed. There was rapid resolution of hypotension and hypoxia and he survived to be discharged home. This case is used to illustrate that no potential therapy should be discounted in patients faced with acute life-threatening PE. Decisions to thrombolyse patients with traditional contraindications-even those considered absolute-must be taken by clinicians able to weigh relative risks.

Clinical controversies in thrombolytic therapy for the management of acute pulmonary embolism

Acute pulmonary embolism is a common complication in hospitalized patients, spanning multiple patient populations and crossing various therapeutic disciplines. Due to the heterogeneous clinical manifestations, the selection of management strategies for patients with acute pulmonary embolism is a challenge for clinicians, and a nuanced understanding of the relevant literature is required. Previous studies that evaluated thrombolytic therapy in patients with acute pulmonary embolism are limited and controversial. Thus, we sought to identify the clinical controversies related to thrombolytic therapy in acute pulmonary embolism and reviewed the recent literature that impacts clinical practice. To apply these controversies into daily clinical practice and decision making, we provide an overview of risk stratification and assessment of pulmonary embolism. Specific areas of controversies that are discussed relate to the impact of thrombolytic therapy on outcomes, specifically in submassive pulmonary embolism, including mortality, composite primary end points, and intensive care unit length of stay. Other controversies relate to the impact of the patient's sex on outcomes, the most safe and effective thrombolytic dose, optimal administration techniques including infusion duration or concurrent anticoagulation, and therapeutic strategies when thrombolytic therapy is unsuccessful. Despite published guidelines and review articles, select aspects of thrombolytic therapy for the management of pulmonary embolism remain controversial; therefore, clinical practice varies from institution to institution and from practitioner to practitioner. When making decisions about the role of thrombolytic therapy in patients with pulmonary embolism, clinicians must be knowledgeable about areas with limited evidence and the therapy's associated risks. In every situation, practitioners must consider the trajectory of the patient's status and the ability to intervene in an appropriate time frame.