Treatment of submassive pulmonary embolism with tenecteplase or placebo: cardiopulmonary outcomes at 3 months: multicenter double-blind, placebo-controlled randomized trial

Pulmonary Embolism Response to Fragmentation, Embolectomy, and Catheter Thrombolysis (PERFECT): Initial Results From a Prospective Multicenter Registry

BACKGROUND

Systemic thrombolysis for acute pulmonary embolism (PE) carries up to a 20% risk of major bleeding, including a 2% to 5% risk of hemorrhagic stroke. We evaluated the safety and effectiveness of catheter-directed therapy (CDT) as an alternative treatment of acute PE.

METHODS

One hundred one consecutive patients receiving CDT for acute PE were prospectively enrolled in a multicenter registry. Massive PE (n = 28) and submassive PE (n = 73) were treated with immediate catheter-directed mechanical or pharmacomechanical thrombectomy and/or catheter-directed thrombolysis through low-dose hourly drug infusion with tissue plasminogen activator (tPA) or urokinase. Clinical success was defined as meeting all the following criteria: stabilization of hemodynamics; improvement in pulmonary hypertension, right-sided heart strain, or both; and survival to hospital discharge. Primary safety outcomes were major procedure-related complications and major bleeding events.

RESULTS

Fifty-three men and 48 women (average age, 60 years [range, 22-86 years]; mean BMI, 31.03 ± 7.20 kg/m2) were included in the study. The average thrombolytic doses were 28.0 ± 11 mg tPA (n = 76) and 2,697,101 ± 936,287 International Units for urokinase (n = 23). Clinical success was achieved in 24 of 28 patients with massive PE (85.7%; 95% CI, 67.3%-96.0%) and 71 of 73 patients with submassive PE (97.3%; 95% CI, 90.5%-99.7%). The mean pulmonary artery pressure improved from 51.17 ± 14.06 to 37.23 ± 15.81 mm Hg (n = 92) (P < .0001). Among patients monitored with follow-up echocardiography, 57 of 64 (89.1%; 95% CI, 78.8%-95.5%; P < .0001) showed improvement in right-sided heart strain. There were no major procedure-related complications, major hemorrhages, or hemorrhagic strokes.

CONCLUSIONS

CDT improves clinical outcomes in patients with acute PE while minimizing the risk of major bleeding. At experienced centers, CDT is a safe and effective treatment of both acute massive and submassive PE.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01097928; URL: www.clinicaltrials.gov.

Four key questions surrounding thrombolytic therapy for submassive pulmonary embolism

Submassive pulmonary embolism (PE) remains a vexing entity, and the appropriate use of thrombolytic therapy for this subgroup continues to be actively debated. Catheter-directed thrombolysis has shown efficacy for submassive PE and is gaining momentum because of theoretically improved safety. This review poses and responds to four questions that explore the complex issues surrounding optimal therapy of submassive PE.

Thrombolytic therapy for pulmonary embolism

BACKGROUND

Thrombolytic therapy (powerful anticoagulation drugs) is usually reserved for patients with clinically serious or massive pulmonary embolism (PE). Evidence suggests that thrombolytic agents may dissolve blood clots more rapidly than heparin and reduce the death rate associated with PE. However, there are still concerns about the possible risk of adverse effects of thrombolytic therapy, such as major or minor haemorrhages. This is the second update of the Cochrane review first published in 2006.

OBJECTIVES

To assess the effects of thrombolytic therapy in patients with acute pulmonary embolism.

SEARCH METHODS

For this update the Cochrane Vascular Group searched their Specialised Register (last searched September 2014) and the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library (last searched Issue 8, 2014). We also searched individual trial collections and private databases, along with bibliographies of relevant articles. We handsearched relevant medical journals.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared thrombolytic therapy followed by heparin versus heparin alone, heparin plus placebo or surgical intervention in patients with acute PE. We did not include trials comparing two different thrombolytic agents or different doses of the same thrombolytic drug.

DATA COLLECTION AND ANALYSIS

Two authors (BD and QH) assessed the eligibility and quality of trials and extracted data.

MAIN RESULTS

We identified 18 trials with a total of 2197 participants for inclusion in the review. We were not able to include one study in the meta-analysis because it had no data to extract. Most of the studies carried a high risk of bias because of high or unclear risk relating to randomisation and blinding. Meta-analysis showed that, compared with heparin alone, or heparin plus placebo, thrombolytics plus heparin can reduce the odds of death (odds ratio (OR) 0.57, 95% confidence interval (CI) 0.37 to 0.87, P = 0.02, low quality evidence) and recurrence of PE (OR 0.51; 95% CI 0.29 to 0.89, P = 0.02, low quality evidence). The effects of death weakened when we excluded four studies at high risk of bias from analysis: OR 0.66, 95% CI 0.42 to 1.06, P = 0.08. The incidence of major and minor haemorrhagic events was higher in the thrombolytics group than in the control group, and this difference was statistically significant (OR 2.90, 95% CI 1.95 to 4.31, P < 0.001, low quality evidence; OR 3.09, 95% CI 1.58 to 6.06, P = 0.001, very low quality evidence, respectively). Length of hospital stay (mean difference (MD) -1.35, 95% CI -4.27 to 1.58) and quality of life were similar between the two treatment groups. Stroke was reported in one study and occurred more often in the thrombolytics group than in the control group, although the confidence interval was wide (OR 12.10, 95% CI 1.57 to 93.39). Limited information from a small number of trials indicated that thrombolytics may improve haemodynamic outcomes, perfusion lung scanning, pulmonary angiogram assessment, echocardiograms, pulmonary hypertension, coagulation parameters, clinical outcomes and survival time to a greater extent than heparin alone. However, the heterogeneity of the studies and small number of participants involved warrant caution when interpreting results. Similarily, fewer patients from the thrombolytics group required escalation of treatment. None of the included studies reported on post-thrombotic syndrome or compared the cost of the different treatments.

AUTHORS' CONCLUSIONS

There is low quality evidence that thrombolytics reduce death following acute pulmonary embolism compared with heparin. Furthermore, thrombolytic therapies included in the review were heterogeneous. Thrombolytic therapy may be helpful in reducing the recurrence of pulmonary emboli but may cause more major and minor haemorrhagic events and stroke. More high quality double blind RCTs assessing safety and cost-effectiveness are required.

Thrombolysis for acute intermediate-risk pulmonary embolism: A meta-analysis

BACKGROUND

The use of thrombolytic therapy in patients with intermediate-risk pulmonary embolism is controversial. To compare with anticoagulation alone, no analysis before has determined whether thrombolytic therapy is associated with improved survival or lower incidence of adverse clinical outcomes for intermediate-risk pulmonary embolism.

OBJECTIVE

This meta-analysis was performed to assess mortality benefits, bleeding and recurrent pulmonary embolism risks associated with thrombolytic therapy compared with anticoagulation in patients with intermediate-risk pulmonary embolism.

METHODS

The Web of Science, PubMed, Embase, EBSCO, and the Cochrane Library databases were searched for randomized clinical trials comparing thrombolytic therapy with anticoagulation in intermediate-risk pulmonary embolism patients (in which the mortality data were reported) from inception to August 5, 2014. Primary outcomes were all-cause mortality and major bleeding. Secondary outcomes were recurrent pulmonary embolism and minor bleeding. The pooled relative risk (RR), Mantel-Haenszel corresponding method and fixed-effect model were used to estimate the efficacy and safety of thrombolytic therapy with 95% confidence intervals.

RESULTS

Eight clinical randomized controlled trials involving 1755 patients with intermediate-risk pulmonary embolism were included. Patients treated with thrombolytics presented lower mortality than patients in the anticoagulation cohort (RR, 0.52; 95% CI, 0.28-0.97; 1.39% [12/866] vs. 2.92% [26/889]). Compared with anticoagulation, thrombolytic therapy was associated with a higher risk of major (RR, 3.35; 95% CI, 2.03-5.54; 7.80% [64/820] vs. 2.28% [19/834]) and minor (RR, 3.66; 95% CI, 2.77-4.84; 32.78% [197/601] vs. 8.94% [53/593]) bleeding. Furthermore, thrombolytic therapy was associated with a lower incidence of recurrent pulmonary embolism (RR, 0.33; 95% CI, 0.15-0.73; 0.73% [6/826] vs. 2.72% [23/846]).

CONCLUSION

Compared with anticoagulation, thrombolytic therapy in patients with intermediate-risk pulmonary embolism is associated with lower all-cause mortality and recurrent pulmonary embolism risk despite increased major and minor bleeding risks.

Initial thrombolysis treatment compared with anticoagulation for acute intermediate-risk pulmonary embolism: a meta-analysis

BACKGROUND

The use of thrombolysis in patients with acute, intermediate-risk pulmonary embolism (PE) remains controversial. This meta-analysis compared the efficacy and safety of thrombolysis and anticoagulation treatments for intermediate-risk PE patients.

METHODS

Two investigators independently reviewed the literature and collected data from randomized controlled trials (RCTs) of thrombolysis for intermediate-risk PE in the PubMed, MEDLINE, EMBASE, the Cochrane Library, and Chinese Biomedical Literature Databases (CBM).

RESULTS

A total of 1,631 intermediate-risk PE patients from seven studies were included. Significant differences were not found regarding the 30-day, all-cause mortality rates between the thrombolytic and anticoagulant groups [odds ratio (OR), 0.60; 95% confident interval (CI), 0.34-1.06; P=0.08]. The rate of clinical deterioration in the thrombolytic group was lower than that in the anticoagulant group (OR, 0.27; 95% CI, 0.18-0.41; P<0.01). Recurrent PE in the thrombolytic group was also significantly lower than that in the anticoagulant group (OR, 0.34; 95% CI, 0.15-0.77; P=0.01). Comparing the thrombolytic and anticoagulation groups, the incidence of minor bleeding was significantly higher in the thrombolytic group (OR, 5.33; 95% CI, 2.85-9.97; P<0.00001), but there were no difference in the incidences of major bleeding events (OR, 2.07; 95% CI, 0.60-7.16; P=0.25).

CONCLUSIONS

Thrombolytic treatment for intermediate-risk PE patients, if not contraindicated, could reduce clinical deterioration and recurrence of PE, and trends towards a decrease in all-cause, 30-day mortality. Despite thrombolytic treatment having an increased total bleeding risk, there was no difference in the incidence of major bleeding events, compared with patients receiving anticoagulation treatment.

Interventional therapy for venous thromboembolism

Advances in image-guided, catheter-based interventions have shown great potential to improve outcomes in patients with venous thromboembolism. Catheter-directed thrombolysis has been shown in one randomized controlled trial to reduce the risk of post-thrombotic syndrome in patients with acute lower extremity deep vein thrombosis; data from a larger national institute of health trial are expected in early 2017. The use of catheter-directed thrombolysis is also being increasingly considered for patients with submassive or massive pulmonary embolism. Preliminary studies suggest that endovascular stent placement and ablative therapies may be used to reduce symptoms and improve quality of life in severely affected patients with established post-thrombotic syndrome. In this article, we summarize the risks and benefits of endovascular venous thromboembolism therapies as currently understood, highlight clinical situations where their benefit may outweigh risks, and describe ongoing and upcoming pivotal research initiatives with multidisciplinary participation.

Pulmonary embolism: whom to discharge and whom to thrombolyze?

Patients with pulmonary embolism can be divided in two groups according to their risk of death or major complication: a small group of high-risk patients defined by the presence of systemic hypotension or cardiogenic shock and a large group of normotensive patients. Among normotensive patients, further risk stratification, based on clinical grounds alone or on the combination of clinical data, biomarkers, and imaging tests, allows selection of low-risk patients and intermediate-risk patients. The safety of outpatient treatment for low-risk patients has been established mainly on the basis of retrospective and prospective cohorts using different selection tools. In most studies, about 50% of the patients have been safely treated at home. Although thrombolytic therapy has a favorable benefit to risk profile in patients with high-risk pulmonary embolism, the risk of major and especially intracranial bleeding outweighs the benefits in terms of hemodynamic decompensation in patients with intermediate-risk pulmonary embolism.

Bleeding risk with systemic thrombolytic therapy for pulmonary embolism: scope of the problem

Acute pulmonary embolism represents a major complication of venous thromboembolism that is associated with high morbidity and mortality. Guidelines recommend the rapid initiation of anticoagulation and consideration of thrombolytic therapy in select patients, including those with hypotension or at high risk of developing hypotension. Evaluation for thrombolytic therapy should only be considered after assessment of contraindications and risk for major bleeding. The objective of this perspective article is to evaluate the bleeding risk associated with systemic thrombolytic therapy in the management of acute pulmonary embolism and discuss strategies to minimize this risk. Risk stratification of acute pulmonary embolism will be discussed to identify patient populations that warrant specific consideration of risk for major bleeding with thrombolytic therapy. In addition, the incidence, patient-specific risk factors, and pharmacologic characteristics, including concurrent anticoagulation and thrombolytic therapy, will be evaluated in the context of risk for major hemorrhage. Finally, supporting evidence for strategies to minimize risk of hemorrhage, including evaluation of contraindications, weight adjusted dosing, infusion strategy and catheter-directed thrombolytic administration will be evaluated. Despite published guidelines and review articles, select aspects to thrombolytic therapy for the management of pulmonary embolism remain controversial and under recognized, including risk of major hemorrhage. When making decisions about the role of thrombolytic therapy in pulmonary embolism, clinicians must be knowledgeable about the associated risks of thrombolytic therapy and individually evaluate patient risk factors prior to determining appropriate candidacy for thrombolytic therapy. For patients considered to be at high risk of major bleeding, strategies to minimize risk should be considered, including weight-adjusted doses and catheter directed therapy. Additional research is needed specific to the acute pulmonary embolism setting to validate risk factors and strategies to minimize major hemorrhage.

Focused cardiac ultrasound: uncommon but critical diagnoses made at the point of care

Cardiovascular and respiratory conditions in acute care require rapid, critical decision making, often with limited clinical information. Focused cardiac ultrasound (FOCUS) can aid in diagnosis by providing information that may not be evident from a patient's medical history, physical examination, and ancillary tests. Eight cases are presented in which FOCUS drastically altered the management of patient care, shortened the differential diagnosis, or allowed for the development of a definitive diagnosis. In 3 cases, diagnoses that were not initially suspected were identified by FOCUS. In the remaining cases, uncommon yet critical diagnoses were established at early stages along the patients' courses of care.

Acute phase treatment of venous thromboembolism: advanced therapy. Systemic fibrinolysis and pharmacomechanical therapy

Venous thromboembolism, which encompasses deep-vein thrombosis and acute pulmonary embolism (PE), represents a major contributor to global disease burden worldwide. For patients who present with cardiogenic shock or persistent hypotension (acute high-risk PE), there is consensus that immediate reperfusion treatment applying systemic fibrinolysis or, in the case of a high bleeding risk, surgical or catheter-directed techniques, is indicated. On the other hand, for the large, heterogeneous group of patients presenting without overt haemodynamic instability, the indications for advanced therapy are less clear. The recently updated guidelines of the European Society of Cardiology emphasise the importance of clinical prediction rules in combination with imaging procedures (assessment of right ventricular function) and laboratory biomarkers (indicative of myocardial stress or injury) for distinguishing between an intermediate and a low risk for an adverse early outcome. In intermediate-high-risk PE defined by the presence of both right ventricular dysfunction on echocardiography (or computed tomography) and a positive troponin (or natriuretic peptide) test, the bleeding risks of full-dose fibrinolytic treatment have been shown to outweigh its potential clinical benefits unless clinical signs of haemodynamic decompensation appear (rescue fibrinolysis). Recently published trials suggest that catheter-directed, ultrasound-assisted, low-dose local fibrinolysis may provide an effective and particularly safe treatment option for some of these patients.

Usefulness and safety of ultrasound-assisted catheter-directed thrombolysis for submassive pulmonary emboli

The optimal treatment for intermediate-risk pulmonary embolism (PE) remains unclear. Our goal was to describe the safety and efficacy of the EkoSonic ultrasound-assisted catheter-directed thrombolysis system (EKOS Corporation, Bothell, Washington) in a real-world registry of patients with intermediate-risk PE. Fifty-three consecutive patients with intermediate-risk PE treated with ultrasound-assisted catheter-directed thrombolysis at Brigham and Women's Hospital from 2010 to 2014 were analyzed. The primary outcome was a change in directly measured pulmonary artery pressures as assessed using logistic regression with generalized estimating equations to account for serial measurements. Patients received an average of 24.6 ± 9 mg of alteplase using the EKOS catheter with an average treatment time of 15.9 ± 3 hours. After treatment, there was a 7.2- and a 11.4-mm Hg reduction in mean and systolic pulmonary artery pressure (95% confidence interval 4.7 to 9.7 mm Hg, p <0.001, and 95% confidence interval 7.8 to 15.0 mm Hg, p <0.001), respectively. In this cohort, 9.4% had any bleeding complication noted during their hospital stay. One patient's alteplase was prematurely discontinued for access site bleeding although no other interventions were required related to bleeding complications.

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.

Respiratory review of 2014: pulmonary thromboembolism

Venous thromboembolism (VTE), which includes pulmonary embolism and deep vein thrombosis, is an important cause of morbidity and mortality. The aim of this review is to summarize the findings from clinically important publications over the last year in the area of VTE. In this review, we discuss 11 randomized controlled trials published from March 2013 to April 2014. The COAG and the EU-PACT trials indicate that pharmacogenetic testing has either no usefulness in the initial dosing of vitamin K antagonists or marginal usefulness in the Caucasian population. Recent clinical trials with novel oral anticoagulants (NOACs) have demonstrated that the efficacy and safety of rivaroxaban, apixaban, edoxaban, and dabigatran are not inferior to those of conventional anticoagulants for the treatment of VTE. The PEITHO and ULTIMA trials suggested that rescue thrombolysis or catheter-directed thrombolysis may maximize the clinical benefits and minimize the bleeding risk. Lastly, riociguat has a proven efficacy in treating chronic thromboembolic pulmonary hypertension. In the future, NOACs, riociguat, and catheter-directed thrombolysis have the potential to revolutionize the management of patients with VTE.

Acute pulmonary embolus: the next frontier in venous thromboembolic interventions

OPINION STATEMENT

Submassive pulmonary embolism (PE) represents a patient population that is under-recognized and under-treated. Recent clinical trials demonstrated the hemodynamic benefit of IV thrombolytic therapy among these patients; however, it came at the cost of a significantly increased risk of major, particularly intracranial, hemorrhage. Catheter-based treatment modalities have garnered considerable clinical interest in recent years. In particular, ultrasound accelerated thrombolysis, a catheter-based technology that enhances the process of thrombolytic delivery into the thrombus, has emerged as a treatment modality with an increasing number of single-center studies, as well as randomized, controlled clinical trials. Results from these experiences are consistent in achieving outcomes of thrombus resolution and hemodynamic recovery with a low dose thrombolytic infusion protocol, but without the high risk of bleeding complications associated with IV thrombolysis. The clinical data will hopefully be impactful to the development of the next edition of the treatment guidelines, in support of overall recommendations for catheter-based interventions. When available and with appropriate expertise, this modality should be considered as the preferred treatment of both massive and submassive PE.

Impact of the efficacy of thrombolytic therapy on the mortality of patients with acute submassive pulmonary embolism: a meta-analysis

BACKGROUND

The efficacy of thrombolytic therapy in patients with submassive pulmonary embolism (PE) remains unclear. Previous meta-analyses have not separately reported the proportion of patients with submassive PE.

OBJECTIVE

We assessed the effect of thrombolytic therapy on mortality, recurrent PE, clinical deterioration requiring treatment escalation and bleeding in patients with submassive PE.

METHODS

The MEDLINE, EMBASE and Cochrane Library databases were searched to identify all relevant randomized controlled trials comparing adjunctive thrombolytic therapy with heparin alone as initial treatments in patients with acute submassive PE, and reported 30-day mortality or in-hospital clinical outcomes.

RESULTS

A total of 1510 patients were enrolled in this meta-analysis. No significant differences were apparent in the composite endpoint of all-cause death or recurrent PE between the adjunctive thrombolytic therapy arm and the heparin-alone arm (3.1% vs. 5.4%; RR, 0.64 [0.32-1.28]; P = 0.2). Adjunctive thrombolytic therapy significantly reduced the incidence of the composite endpoint of all-cause death or clinical deterioration (3.9% vs. 9.4%; RR, 0.44; P < 0.001). There were no statistically significant associations for major bleeding when adjunctive thrombolytic therapy was compared with heparin therapy alone (6.6% vs. 1.9%; P = 0.2).

CONCLUSIONS

This meta-analysis shows that adjunctive thrombolytic therapy does not significantly reduce the risk of mortality or recurrent PE in patients with acute submassive PE, but that adjuvant thrombolytic therapy prevents clinical deterioration requiring the escalation of treatment in patients with acute submassive PE. Bleeding risk assessment might be the most successful approach for improving clinical outcomes and patient-specific benefit.

Right ventricular dysfunction as an echocardiographic prognostic factor in hemodynamically stable patients with acute pulmonary embolism: a meta-analysis

BACKGROUND

We investigated whether right ventricular dysfunction (RVD) as assessed by echocardiogram can be used as a prognostic factor in hemodynamically stable patients with acute pulmonary embolism (PE). Short-term mortality has been investigated only in small studies and the results have been controversial.

METHODS

A PubMed search was conducted using two keywords, "pulmonary embolism" and "echocardiogram", for articles published between January 1st 1998 and December 31st 2011. Out of 991 articles, after careful review, we found 12 articles that investigated the implications of RVD as assessed by echocardiogram in predicting short-term mortality for hemodynamically stable patients with acute PE. We conducted a meta-analysis of these data to identify whether the presence of RVD increased short-term mortality.

RESULTS

Among 3283 hemodynamically stable patients with acute PE, 1223 patients (37.3%) had RVD, as assessed by echocardiogram, while 2060 patients (62.7%) had normal right ventricular function. Short-term mortality was reported in 167 (13.7%) out of 1223 patients with RVD and in 134 (6.5%) out of 2060 patients without RVD. Hemodynamically stable patients with acute PE who had RVD as assessed by echocardiogram had a 2.29-fold increase in short-term mortality (odds ratio 2.29, 95% confidence interval 1.61-3.26) compared with patients without RVD.

CONCLUSIONS

In hemodynamically stable patients with acute PE, RVD as assessed by echocardiogram increases short-term mortality by 2.29 times. Consideration should be given to obtaining echocardiogram to identify high-risk patients even if they are hemodynamically stable.