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

Submassive Pulmonary Embolism: Current Perspectives and Future Directions

Submassive pulmonary embolism (PE) lies on a spectrum of disease severity between standard and high-risk disease. By definition, patients with submassive PE have a worse outcome than the majority of those with standard-risk PE, who are hemodynamically stable and lack imaging or laboratory features of cardiac dysfunction. Systemic thrombolytic therapy has been proven to reduce mortality in patients with high-risk disease; however, its use in submassive PE has not demonstrated a clear benefit, with haemodynamic improvements being offset by excess bleeding. Furthermore, meta-analyses have been confusing, with conflicting results on overall survival and net gain. As such, significant interest remains in optimising thrombolysis, with recent efforts in catheter-based delivery as well as upcoming studies on reduced systemic dosing. Recently, long-term cardiorespiratory limitations following submassive PE have been described, termed post-PE syndrome. Studies on the ability of thrombolytic therapy to prevent this condition also present conflicting evidence. In this review, we aim to clarify the current evidence with respect to submassive PE management, and also to highlight shortcomings in current definitions and prognostic factors. Additionally, we discuss novel therapies currently in preclinical and early clinical trials that may improve outcomes in patients with submassive PE.

Thrombolytics for venous thromboembolic events: a systematic review with meta-analysis

Thrombolytic therapy might reduce venous thromboembolism-related mortality and morbidity, but it could also increase the risk of major bleeding. We systematically reviewed the literature to evaluate the effectiveness and safety of thrombolytics in patients with pulmonary embolism (PE) and/or deep venous thrombosis (DVT). We searched Medline, Embase, and Cochrane databases for relevant randomized controlled trials up to February 2019. Multiple investigators independently screened and collected data. We included 45 studies (4740 participants). Pooled estimates of PE studies indicate probable reduction in mortality with thrombolysis (risk ratio [RR], 0.61; 95% confidence interval [CI], 0.40-0.94) (moderate certainty) and possible reduction in nonfatal PE recurrence (RR, 0.56; 95% CI, 0.35-0.89) (low certainty). Pooled estimates of DVT studies indicate the possible absence of effects on mortality (RR, 0.77; 95% CI, 0.26-2.28) (low certainty) and recurrent DVT (RR, 0.99; 95% CI, 0.56-1.76) (low certainty), but possible reduction in postthrombotic syndrome (PTS) with thrombolytics (RR, 0.70; 95% CI, 0.59-0.83) (low certainty). Pooled estimates of the complete body of evidence indicate increases in major bleeding (RR, 1.89; 95% CI, 1.46-2.46) (high certainty) and a probable increase in intracranial bleeding (RR, 3.17; 95% CI 1.19-8.41) (moderate certainty) with thrombolytics. Our findings indicate that thrombolytics probably reduce mortality in patients with submassive- or intermediate-risk PE and may reduce PTS in patients with proximal DVT at the expense of a significant increase in major bleeding. Because the balance between benefits and harms is profoundly influenced by the baseline risks of critical outcomes, stakeholders involved in decision making would need to weigh these effects to define which clinical scenarios merit the use of thrombolytics.

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.

Successful Surgical Embolectomy for a Rapidly Deteriorating Patient with Pulmonary Embolism and Hemorrhagic Stroke

Pulmonary embolism (PE) is a life-threatening condition. High-risk PE is defined as pulmonary embolism with either hemodynamic collapse, persistent hypotension, and/or organ hypoperfusion. The overall mortality rate associated with high-risk PE remains at approximately 30%.

Intermediate–high risk PE is a new term introduced to identify hemodynamically stable PE patients with evidence of right ventricular dysfunction.

Thrombolytics therapy is the first choice for treatment of high-risk PE with hemodynamic instability; however, in a patient who failed thrombolytics or have contraindication to thrombolytics, thrombus removal either with open surgical or catheter embolectomy is a good alternative.

We report a case of a patient who presented with hemorrhagic stroke complicated by intermediate–high-risk PE that rapidly deteriorated before undergoing successful surgical embolectomy.

Thrombolytic therapy for pulmonary embolism

BACKGROUND

Thrombolytic therapy is usually reserved for people with clinically serious or massive pulmonary embolism (PE). Evidence suggests that thrombolytic agents may dissolve blood clots more rapidly than heparin and may 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 haemorrhage. This is the fourth update of the Cochrane review first published in 2006.

OBJECTIVES

To assess the effects of thrombolytic therapy for acute pulmonary embolism.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 17 August 2020. We undertook reference checking to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared thrombolytic therapy followed by heparin versus heparin alone, heparin plus placebo, or surgical intervention for people with acute PE (massive/submassive). We did not include trials comparing two different thrombolytic agents or different doses of the same thrombolytic drug.

DATA COLLECTION AND ANALYSIS

Two review authors (ZZ, QH) assessed the eligibility and risk of bias of trials and extracted data. We calculated effect estimates using the odds ratio (OR) with a 95% confidence interval (CI) or the mean difference (MD) with a 95% CI. The primary outcomes of interest were death, recurrence of PE and haemorrhagic events. We assessed the certainty of the evidence using GRADE criteria.

MAIN RESULTS

We identified three new studies for inclusion in this update. We included 21 trials in the review, with a total of 2401 participants. No studies compared thrombolytics versus surgical intervention. We were not able to include one study in the meta-analysis because it provided no extractable data. Most studies carried a high or unclear risk of bias related to randomisation and blinding. Meta-analysis showed that, compared to control (heparin alone or heparin plus placebo), thrombolytics plus heparin probably reduce both the odds of death (OR 0.58, 95% CI 0.38 to 0.88; 19 studies, 2319 participants; low-certainty evidence), and recurrence of PE (OR 0.54, 95% CI 0.32 to 0.91; 12 studies, 2050 participants; low-certainty evidence). Effects on mortality weakened when six studies at high risk of bias were excluded from analysis (OR 0.71, 95% CI 0.45 to 1.13; 13 studies, 2046 participants) and in the analysis of submassive PE participants (OR 0.61, 95% CI 0.37 to 1.02; 1993 participants). Effects on recurrence of PE also weakened after removing one study at high risk of bias for sensitivity analysis (OR 0.60, 95% CI 0.35 to 1.04; 11 studies, 1949 participants). We downgraded the certainty of evidence to low because of 'Risk of bias' concerns. Major haemorrhagic events were probably more common in the thrombolytics group than in the control group (OR 2.84, 95% CI 1.92 to 4.20; 15 studies, 2101 participants; moderate-certainty evidence), as were minor haemorrhagic events (OR 2.97, 95% CI 1.66 to 5.30; 13 studies,1757 participants; low-certainty evidence). We downgraded the certainty of the evidence to moderate or low because of 'Risk of bias' concerns and inconsistency. Haemorrhagic stroke may occur more often in the thrombolytics group than in the control group (OR 7.59, 95% CI 1.38 to 41.72; 2 studies, 1091 participants). Limited data indicated that thrombolytics may benefit haemodynamic outcomes, perfusion lung scanning, pulmonary angiogram assessment, echocardiograms, pulmonary hypertension, coagulation parameters, composite clinical outcomes, need for escalation and survival time to a greater extent than heparin alone. However, the heterogeneity of the studies and the small number of participants involved warrant caution when interpreting results. The length of hospital stay was shorter in the thrombolytics group than in the control group (mean difference (MD) -1.40 days, 95% CI -2.69 to -0.11; 5 studies, 368 participants). Haemodynamic decompensation may occur less in the thrombolytics group than in the control group (OR 0.36, 95% CI 0.20 to 0.66; 3 studies, 1157 participants). Quality of life was similar between the two treatment groups. None of the included studies provided data on post-thrombotic syndrome or on cost comparison.

AUTHORS' CONCLUSIONS

Low-certainty evidence suggests that thrombolytics may reduce death following acute pulmonary embolism compared with heparin (the effectiveness was mainly driven by one trial with massive PE). Thrombolytic therapy may be helpful in reducing the recurrence of pulmonary emboli but may cause more major and minor haemorrhagic events, including haemorrhagic stroke. More studies of high methodological quality are needed to assess safety and cost effectiveness of thrombolytic therapy for people with pulmonary embolism.

Low-dose urokinase thrombolytic therapy for patients with acute intermediate-high-risk pulmonary embolism: A retrospective cohort study

Introduction

Patients at intermediate-high risk of developing a pulmonary embolism (PE) are very likely to experience adverse outcomes, such as cardiovascular instability and death. The role of thrombolytic therapy in intermediate-high-risk PE remains controversial.

Objectives

This study aimed to determine the efficacy and safety of low-dose urokinase (UK) thrombolytic therapy for intermediate-high-risk PE.

Patients and methods

This retrospective study included 81 consecutive patients with intermediate-high-risk PE from two centers. Patients received low-dose UK or low-molecular-weight heparin (anticoagulant therapy group). The efficacy outcomes were mortality, computed tomography pulmonary angiography (CTPA)-confirmed absorption, and dyspnea. Safety was assessed as the incidence of bleedings.

Results

The in-hospital mortality, 9-month mortality, and long-term mortality at the last follow-up were comparable for the low-dose UK group and the anticoagulant therapy group (6.45% vs. 0%, p = 0.144, 9.68% vs. 8.16%, p = 0.815, and 12.90% vs. 12.24%, p = 0.931, respectively). CTPA-confirmed absorption at one month after admission was higher in the low-dose UK group than in the anticoagulant therapy group (p = 0.016). The incidences of short-term dyspnea at discharge and long-term dyspnea at the last follow-up were lower in the low-dose UK group than in the anticoagulant therapy group (27.59% vs. 52%, p = 0.035, 33.33% vs. 58.14%, p = 0.043, respectively). No major bleeding occurred. The incidence of minor bleeding was not significantly different between the two groups (3.23% vs. 6%, p = 0.974).

Conclusion

In intermediate-high-risk PE, a low-dose UK might increase CTPA-confirmed absorption and improve short-term and long-term dyspnea without affecting mortality or increasing the bleeding risk.

Successful thrombolysis of normotensive pulmonary embolism with life-threatening hypoxia in a young man with Klinefelter syndrome

Klinefelter syndrome (KS) affects males born with an additional X chromosome giving the genotype 47XXY classically. This syndrome has primary features of infertility and hypogonadism along with other features including a genetically hypercoagulable state. When associated with other risk factors, KS further increases the risk of venous thromboembolism and could result in life-threatening pulmonary embolism (PE). There should be a lower threshold in suspecting PE as a cause of acute respiratory failure in this patient group and thrombolysis should be considered early in normotensive PE with severe hypoxia for best patient outcomes. Furthermore, clinicians should be cautious in managing testosterone therapy in patients with KS and additional thromboembolic risk factors.

Aggressive Therapy for Acute Pulmonary Embolism: Systemic Thrombolysis and Catheter-Directed Approaches

Venous thromboembolism (VTE) is the third most common cause of cardiovascular disease after myocardial infarction and stroke. Population-based studies estimate that up to 94,000 new cases of pulmonary embolism (PE) occur in the United States annually with an increasing incidence with age. Mortality from PE is the greatest in the first 24 hours, with a decreased survival extending out 3 months. Thus, acute PE is a potentially fatal illness if not recognized and treated in a timely manner. Contemporary management includes systemic anticoagulation, thrombolysis, catheter-based procedures, and surgical embolectomy. This article reviews current clinical evidence and societal guidelines for the use of systemic and catheter-directed thrombolysis for treatment of acute PE.

Clinical outcomes of submassive pulmonary embolism thrombolysis-an Indian experience

BACKGROUND

Acute pulmonary thromboembolism is the most dangerous presentation of venous thromboembolic disease. The role of thrombolysis in massive pulmonary embolism has been studied extensively, but the same is not there for submassive pulmonary embolism. This study is aimed at evaluating the effects of thrombolysis in acute submassive pulmonary embolism. This was a prospective, case-control, observational study. Patients presenting with acute submassive pulmonary embolism were divided into thrombolysis group and control group depending on whether they received thrombolysis plus anticoagulation or anticoagulation only, respectively.

RESULTS

A total of 86 patients were included in the study. Forty-two patients were in the thrombolysis group, and 44 patients were in the control group. The mean ± SD age in the control and thrombolysis groups was 63.3 ± 14.7 and 56.4 ± 13.8 years, respectively. The two groups were well matched in sex distribution and associated comorbidities like COPD, active surgery, major trauma, and immobilization. On echocardiography, dilated RA/RV in pre-treatment vs. post-treatment was seen in 20 (45.5%) vs. 20 (45.5%) in the control group and 26 (61.9%) vs. 11 (26.2%) in the thrombolysis group. Similarly, RV systolic dysfunction in pre-treatment vs. post-treatment was seen in 24 (54.5%) vs. 21 (47.7%) in the control group and 22 (52.4%) vs. 8 (19.0%) in the thrombolysis group. Pulmonary artery pressure in pre-treatment vs. post-treatment was 64.4 ± 15.0 vs. 45.9 ± 9.9 mmHg in the control group and 68.3 ± 17.4 vs. 31.4 ± 6.9 mmHg in the thrombolysis group. In control vs. thrombolysis group, there were 5 vs. 1 death, 6 vs. 1 hemodynamic decompensation, and 6 vs. 1 patient needing mechanical ventilation.

CONCLUSION

Thrombolysis in submassive pulmonary embolism is associated with better right ventricular functions, lower pulmonary artery pressures, and comparable mortality rates.

Use of hospital resources in the care of patients with intermediate risk pulmonary embolism

BACKGROUND

Risk stratification and management of hemodynamically stable pulmonary embolism remains challenging. Professional societies have published stratification schemes, but little is known about the management of patients with intermediate risk pulmonary embolism. We describe the care of these patients at an academic health system.

METHODS

Patient encounters from 1 January 2016 to 30 June 2017 were retrospectively identified utilizing a multihospital, electronic health record-based data warehouse. Using the 2019 European Society of Cardiology criteria, differences in hospital resource utilization, defined as intensive care unit admission, use of invasive therapies, and length of stay, were examined in patients with intermediate risk characteristics.

RESULTS

A cohort of 322 intermediate risk patients, including 165 intermediate-low and 157 intermediate-high risk patients, was identified. Intermediate-high risk patients more often underwent catheter-directed therapy (14.0% vs. 1.8%; P<0.001) compared to intermediate-low risk patients and had a 50% higher rate of intensive care unit admission (relative risk 1.50; 95% confidence interval 1.06, 2.12; P=0.023). There was no difference in median intensive care unit length of stay (2.7 vs. 2.0 days; P=0.761) or hospital length of stay (5.0 vs. 5.0 days; P=0.775) between intermediate-high risk and intermediate-low risk patients. Patients that underwent invasive therapies had a 3.8-day shorter hospital length of stay (beta -3.75; 95% confidence interval -6.17, -1.32; P=0.002).

CONCLUSION

This study presents insights into the hospital resource utilization of patients with intermediate risk pulmonary embolism. The 2019 European Society of Cardiology risk stratification criteria are a clinically relevant scheme that identifies patients more often treated with intensive care unit admission and advanced therapies.

The net benefit of thrombolysis in the management of intermediate risk pulmonary embolism: Systematic review and meta-analysis

Background

Benefit of thrombolytic therapy in patients with massive pulmonary embolism (PE) is evident. However, evidence supporting benefit in clinical outcomes of this approach in intermediate risk PE is lacking.

Objective

To determine the impact of thrombolysis on overall survival in intermediate risk PE patients.

Methods

We searched in MEDLINE (OVID), EMBASE, LILACS, and the Cochrane Central Register of Controlled Trials (CENTRAL) from present day. We also searched in other databases and unpublished literature. We included clinical trials without language restrictions. The risk of bias was evaluated with the Cochrane Collaboration's tool. The primary outcome was overall survival. Secondary outcomes were adverse events, including major bleeding, and all-cause mortality. The measure of the effect was the risk ratio with a 95% confidence interval (CI).

Results

We included 11 studies in the qualitative and quantitative analysis, with a total of 1855 patients. Risk of bias was variable among the study items. There were no results reported about overall survival in any of the studies. The risk ratio (RR) for all-cause mortality was 0.68 95% CI (0.40 to 1.16). The RR of overall bleeding, major bleeding and stroke were 2.72 95% CI (1.58 to 4.69), 2.17 95% CI (1.03 to 4.55), and 2.22 95% CI (0.17 to 28.73), respectively. Additionally, the RR for recurrent PE was 0.56 95% CI (0.23 to 1.37).

Conclusions

In patients with intermediate risk PE, the risk of bleeding is higher when thrombolysis is used. There was no significant difference between thrombolysis and anticoagulation in recurrence of PE, stroke, and all-cause mortality.

Fibrinolytics for the treatment of pulmonary embolism

The use of fibrinolytic agents in acute pulmonary embolism (PE), first described over 50 years ago, hastens the resolution of RV stain, leading to earlier hemodynamic improvement. However, this benefit comes at the increased risk of bleeding. The strongest indication for fibrinolysis is in high-risk PE, or that characterized by sustained hypotension, while its use in patients with intermediate-risk PE remains controversial. Fibrinolysis is generally not recommended for routine use in intermediate-risk PE, although most guidelines advise that it may be considered in patients with signs of acute decompensation and an overall low bleeding risk. The efficacy of fibrinolysis often varies significantly between patients, which may be at least partially explained by several factors found to promote resistance to fibrinolysis. Ultimately, treatment decisions should carefully weigh the risks and benefits of the individual clinical scenario at hand, including the overall severity, the patient's bleeding risk, and the presence of factors known to promote resistance to fibrinolysis. This review aims to further explore the use of fibrinolytic agents in the treatment of PE including specific indications, outcomes, and special considerations.

Tenecteplase Thrombolysis for Acute Ischemic Stroke

Tenecteplase is a fibrinolytic drug with higher fibrin specificity and longer half-life than the standard stroke thrombolytic, alteplase, permitting the convenience of single bolus administration. Tenecteplase, at 0.5 mg/kg, has regulatory approval to treat ST-segment-elevation myocardial infarction, for which it has equivalent 30-day mortality and fewer systemic hemorrhages. Investigated as a thrombolytic for ischemic stroke over the past 15 years, tenecteplase is currently being studied in several phase 3 trials. Based on a systematic literature search, we provide a qualitative synthesis of published stroke clinical trials of tenecteplase that (1) performed randomized comparisons with alteplase, (2) compared different doses of tenecteplase, or (3) provided unique quantitative meta-analyses. Four phase 2 and one phase 3 study performed randomized comparisons with alteplase. These and other phase 2 studies compared different tenecteplase doses and effects on early outcomes of recanalization, reperfusion, and substantial neurological improvement, as well as symptomatic intracranial hemorrhage and 3-month disability on the modified Rankin Scale. Although no single trial prospectively demonstrated superiority or noninferiority of tenecteplase on clinical outcome, meta-analyses of these trials (1585 patients randomized) point to tenecteplase superiority in recanalization of large vessel occlusions and noninferiority in disability-free 3-month outcome, without increases in symptomatic intracranial hemorrhage or mortality. Doses of 0.25 and 0.4 mg/kg have been tested, but no advantage of the higher dose has been suggested by the results. Current clinical practice guidelines for stroke include intravenous tenecteplase at either dose as a second-tier option, with the 0.25 mg/kg dose recommended for large vessel occlusions, based on a phase 2 trial that demonstrated superior recanalization and improved 3-month outcome relative to alteplase. Ongoing randomized phase 3 trials may better define the comparative risks and benefits of tenecteplase and alteplase for stroke thrombolysis and answer questions of tenecteplase efficacy in the >4.5-hour time window, in wake-up stroke, and in combination with endovascular thrombectomy.

American Society of Hematology 2020 guidelines for management of venous thromboembolism: treatment of deep vein thrombosis and pulmonary embolism

BACKGROUND

Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), occurs in ∼1 to 2 individuals per 1000 each year, corresponding to ∼300 000 to 600 000 events in the United States annually.

OBJECTIVE

These evidence-based guidelines from the American Society of Hematology (ASH) intend to support patients, clinicians, and others in decisions about treatment of VTE.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and adult patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 28 recommendations for the initial management of VTE, primary treatment, secondary prevention, and treatment of recurrent VTE events.

CONCLUSIONS

Strong recommendations include the use of thrombolytic therapy for patients with PE and hemodynamic compromise, use of an international normalized ratio (INR) range of 2.0 to 3.0 over a lower INR range for patients with VTE who use a vitamin K antagonist (VKA) for secondary prevention, and use of indefinite anticoagulation for patients with recurrent unprovoked VTE. Conditional recommendations include the preference for home treatment over hospital-based treatment for uncomplicated DVT and PE at low risk for complications and a preference for direct oral anticoagulants over VKA for primary treatment of VTE.

Current Controversies in Caring for the Critically Ill Pulmonary Embolism Patient

Emergency physicians must be prepared to rapidly diagnose and resuscitate patients with pulmonary embolism (PE). Certain aspects of PE resuscitation run counter to typical approaches. A specific understanding of the pathophysiology of PE is required to avoid cardiovascular collapse potentially associated with excessive intravenous fluids and positive pressure ventilation. Once PE is diagnosed, rapid risk stratification should be performed and treatment guided by patient risk class. Although anticoagulation remains the mainstay of PE treatment, emergency physicians also must understand the indications and contraindications for thrombolysis and should be aware of new therapies and models of care that may improve outcomes.

Acute treatment of venous thromboembolism

All patients with venous thromboembolism (VTE) should receive anticoagulant treatment in the absence of absolute contraindications. Initial anticoagulant treatment is crucial for reducing mortality, preventing early recurrences, and improving long-term outcome. Treatment and patient disposition should be tailored to the severity of clinical presentation, to comorbidities, and to the potential to receive appropriate care in the outpatient setting. Direct oral anticoagulants (DOACs) used in fixed doses without laboratory monitoring are the agents of choice for the treatment of acute VTE in the majority of patients. In comparison with conventional anticoagulation (parenteral anticoagulants followed by vitamin K antagonists), these agents showed improved safety (relative risk [RR] of major bleeding, 0.61; 95% confidence interval [CI], 0.45-0.83) with a similar risk of recurrence (RR, 0.90; 95% CI, 0.77-1.06). Vitamin K antagonists or low molecular weight heparins are still alternatives to DOACs for the treatment of VTE in specific patient categories such as those with severe renal failure or antiphospholipid syndrome, or cancer, respectively. In addition to therapeutic anticoagulation, probably less than 10% of patients require reperfusion by thrombolysis or interventional treatments; those patients are hemodynamically unstable with acute pulmonary embolism, and a minority of them have proximal limb-threatening deep vein thrombosis (DVT). The choice of treatment should be driven by the combination of evidence from clinical trials and by local expertise. The majority of patients with acute DVT and a proportion of selected hemodynamically stable patients with acute pulmonary embolism can be safely managed as outpatients.

Interventional Radiology Therapy: Inferior Vena Cava Filter and Catheter-based Therapies

Endovascular management of pulmonary embolism can be divided into therapeutic and prophylactic treatments. Prophylactic treatment includes inferior vena cava filter placement, whereas endovascular therapeutic interventions include an array of catheter-directed therapies. The indications for both modalities have evolved over the last decade as new evidence has become available.

Thrombolysis in Pulmonary Embolism: An Evidence-Based Approach to Treating Life-Threatening Pulmonary Emboli

Acute pulmonary embolism (PE) is associated with high in-hospital morbidity and mortality, both via cardiorespiratory decompensation and the bleeding complications of treatment. Thrombolytic therapy can be life-saving in those with high-risk PE, but requires careful patient selection. Patients with PE and systemic arterial hypotension ("massive PE") should receive thrombolytic therapy unless severe contraindications are present. Patients with PE and right ventricular dysfunction/injury, but without hypotension ("submassive PE"), should be considered for thrombolysis on a case-by-case basis, considering bleeding risk, cardiac biomarkers, echocardiography, and most importantly, clinical status.

Rivaroxaban treatment for young patients with pulmonary embolism (Review)

Pulmonary embolism (PE) is a serious, life-threatening condition that affects young populations (>18 and <50 years old, according to most literature reviews) with improved recognition of its clinical manifestations and the widespread use of sensitive imaging techniques, PE is increasingly diagnosed in younger patients. At present, there is limited understanding of the clinical features and adequate anticoagulant treatment options for this population. Most studies to date have yet to demonstrate significant differences in PE pathophysiology or symptoms between young and elderly patients. Although the overall incidence of PE is lower in young populations compared with elderly patients, important risk factors also apply for young patients. Hereditary thrombophilia is common and is a major cause of PE in younger patients. Immobilization, trauma, obesity, smoking and infection are also becoming increasingly frequent in young patients with PE. Among female patients, oral contraceptive use, pregnancy and postpartum status are predominant risk factors underlying PE. Rivaroxaban is a direct oral anticoagulant with a rapid onset of action that is associated with less drug-drug interactions compared with other therapies. Because the drug is administered at fixed doses with no requirement for routine coagulation monitoring, it is becoming an attractive option for anticoagulation treatment in young patients with PE. Therefore, the present literature review focuses on the clinical characteristics of PE and rivaroxaban therapy in younger patients.

Systemic Thrombolysis Therapy is Associated With Improved Outcomes Among Patients With Acute Pulmonary Embolism and Respiratory Failure

BACKGROUND

Thrombolytic therapy is widely accepted for massive pulmonary embolism (PE) due to the high mortality risk associated with standard anticoagulation alone. Its role in submassive PE, however, has remained controversial. We aimed to evaluate whether the selective use of systemic thrombolytic therapy with intravenous tissue plasminogen activator (IV-tPA) improves the survival of patients with submassive PE at increased risk for clinical deterioration.

METHODS

A total of 184 consecutive patients diagnosed with acute PE by chest thoracic angiography (CTA) were included in a retrospective study. Pulmonary artery obstruction and right/left ventricular dysfunction were evaluated by CTA and echocardiography. Medical history and simplified PE Severity Index (sPESI) were assessed at diagnosis. Hemodynamic and respiratory status were recorded at diagnosis, admission to pulmonary unit and prior to thrombolytic therapy. Patient survival was assessed at 30 of 90 days from diagnosis by CTA.

RESULTS

All low risk patients (36%) per sPESI survived. Among the 117 remaining patients, 31% received IV-tPA. Respiratory failure was associated with decreased age-adjusted survival (P = 0.005). Among patients with respiratory failure selected for IV-tPA, age-adjusted survival was improved significantly compared to others (P = 0.043).

CONCLUSIONS

Thrombolytic therapy for hemodynamically stable PE patients with respiratory failure may improve survival.

TRIAL REGISTRATION

MMC-0216-14.

Evolution of Acute Pulmonary Embolism Management: Review Article

Acute pulmonary emboli are a major cause of morbidity and mortality and require prompt evaluation, diagnosis, and treatment. To date, anticoagulation using low molecular weight heparin or non-Vitamin K oral anticoagulants has been the mainstay of treatment in the subset of patients in whom pulmonary embolism does not compromise hemodynamics. On the other hand however, patients with massive pulmonary embolism and shock, thrombolytic therapy is necessary. This raises the question whether ultrasound-assisted catheter directed thrombolytic delivery might be superior to systemic administration. This review article aims to consolidate recent literature to help achieve a better understanding toward the utility of catheter directed therapy.

Diagnosis, Treatment and Follow Up of Acute Pulmonary Embolism: Consensus Practice from the PERT Consortium

Pulmonary embolism (PE) is a life-threatening condition and a leading cause of morbidity and mortality. There have been many advances in the field of PE in the last few years, requiring a careful assessment of their impact on patient care. However, variations in recommendations by different clinical guidelines, as well as lack of robust clinical trials, make clinical decisions challenging. The Pulmonary Embolism Response Team Consortium is an international association created to advance the diagnosis, treatment, and outcomes of patients with PE. In this consensus practice document, we provide a comprehensive review of the diagnosis, treatment, and follow-up of acute PE, including both clinical data and consensus opinion to provide guidance for clinicians caring for these patients.

Different strategies for pharmacological thromboprophylaxis for lower-limb immobilisation after injury: systematic review and economic evaluation

BACKGROUND

Thromboprophylaxis can reduce the risk of venous thromboembolism (VTE) during lower-limb immobilisation, but it is unclear whether or not this translates into meaningful health benefit, justifies the risk of bleeding or is cost-effective. Risk assessment models (RAMs) could select higher-risk individuals for thromboprophylaxis.

OBJECTIVES

To determine the clinical effectiveness and cost-effectiveness of different strategies for providing thromboprophylaxis to people with lower-limb immobilisation caused by injury and to identify priorities for future research.

DATA SOURCES

Ten electronic databases and research registers (MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Database of Abstracts of Review of Effects, the Cochrane Central Register of Controlled Trials, Health Technology Assessment database, NHS Economic Evaluation Database, Science Citation Index Expanded, ClinicalTrials.gov and the International Clinical Trials Registry Platform) were searched from inception to May 2017, and this was supplemented by hand-searching reference lists and contacting experts in the field.

REVIEW METHODS

Systematic reviews were undertaken to determine the effectiveness of pharmacological thromboprophylaxis in lower-limb immobilisation and to identify any study of risk factors or RAMs for VTE in lower-limb immobilisation. Study quality was assessed using appropriate tools. A network meta-analysis was undertaken for each outcome in the effectiveness review and the results of risk-prediction studies were presented descriptively. A modified Delphi survey was undertaken to identify risk predictors supported by expert consensus. Decision-analytic modelling was used to estimate the incremental cost per quality-adjusted life-year (QALY) gained of different thromboprophylaxis strategies from the perspectives of the NHS and Personal Social Services.

RESULTS

Data from 6857 participants across 13 trials were included in the meta-analysis. Thromboprophylaxis with low-molecular-weight heparin reduced the risk of any VTE [odds ratio (OR) 0.52, 95% credible interval (CrI) 0.37 to 0.71], clinically detected deep-vein thrombosis (DVT) (OR 0.40, 95% CrI 0.12 to 0.99) and pulmonary embolism (PE) (OR 0.17, 95% CrI 0.01 to 0.88). Thromboprophylaxis with fondaparinux (Arixtra®, Aspen Pharma Trading Ltd, Dublin, Ireland) reduced the risk of any VTE (OR 0.13, 95% CrI 0.05 to 0.30) and clinically detected DVT (OR 0.10, 95% CrI 0.01 to 0.94), but the effect on PE was inconclusive (OR 0.47, 95% CrI 0.01 to 9.54). Estimates of the risk of major bleeding with thromboprophylaxis were inconclusive owing to the small numbers of events. Fifteen studies of risk factors were identified, but only age (ORs 1.05 to 3.48), and injury type were consistently associated with VTE. Six studies of RAMs were identified, but only two reported prognostic accuracy data for VTE, based on small numbers of patients. Expert consensus was achieved for 13 risk predictors in lower-limb immobilisation due to injury. Modelling showed that thromboprophylaxis for all is effective (0.015 QALY gain, 95% CrI 0.004 to 0.029 QALYs) with a cost-effectiveness of £13,524 per QALY, compared with thromboprophylaxis for none. If risk-based strategies are included, it is potentially more cost-effective to limit thromboprophylaxis to patients with a Leiden thrombosis risk in plaster (cast) [L-TRiP(cast)] score of ≥ 9 (£20,000 per QALY threshold) or ≥ 8 (£30,000 per QALY threshold). An optimal threshold on the L-TRiP(cast) receiver operating characteristic curve would have sensitivity of 84-89% and specificity of 46-55%.

LIMITATIONS

Estimates of RAM prognostic accuracy are based on weak evidence. People at risk of bleeding were excluded from trials and, by implication, from modelling.

CONCLUSIONS

Thromboprophylaxis for lower-limb immobilisation due to injury is clinically effective and cost-effective compared with no thromboprophylaxis. Risk-based thromboprophylaxis is potentially optimal but the prognostic accuracy of existing RAMs is uncertain.

FUTURE WORK

Research is required to determine whether or not an appropriate RAM can accurately select higher-risk patients for thromboprophylaxis.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017058688.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Immediate and late impact of reperfusion therapies in acute pulmonary embolism

Haemodynamic instability and right ventricular dysfunction are the key determinants of short-term prognosis in patients with acute pulmonary embolism (PE). Residual thrombi and persistent right ventricular dysfunction may contribute to post-PE functional impairment, and influence the risk of developing chronic thromboembolic pulmonary hypertension. Patients with haemodynamic instability at presentation (high-risk PE) require immediate primary reperfusion to relieve the obstruction in the pulmonary circulation and increase the chances of survival. Surgical removal of the thrombi or catheter-directed reperfusion strategies is alternatives in patients with contraindications to systemic thrombolysis. For haemodynamically stable patients with signs of right ventricular overload or dysfunction (intermediate-risk PE), systemic standard-dose thrombolysis is currently not recommended, because the risk of major bleeding associated with the treatment outweighs its benefits. In such cases, thrombolysis should be considered only as a rescue intervention if haemodynamic decompensation develops. Catheter-directed pharmaco-logical and pharmaco-mechanical techniques ensure swift recovery of echocardiographic and haemodynamic parameters and may be characterized by better safety profile than systemic thrombolysis. For survivors of acute PE, little is known on the effects of reperfusion therapies on the risk of chronic functional and haemodynamic impairment. In intermediate-risk PE patients, available data suggest that systemic thrombolysis may have little impact on long-term symptoms and functional limitation, echocardiographic parameters, and occurrence of chronic thromboembolic pulmonary hypertension. Ongoing and future interventional studies will clarify whether ‘safer’ reperfusion strategies may improve early clinical outcomes without increasing the risk of bleeding and contribute to reducing the burden of long-term complications after intermediate-risk PE.

Evaluation and Management of Intermediate and High-Risk Pulmonary Embolism

OBJECTIVE. The evidence regarding pulmonary embolism treatment has greatly advanced over the past 10 years, particularly in patients with right ventricular dysfunction or hemodynamic instability. Treatment options include systemic anticoagulation, systemic thrombolysis, catheter-assisted thrombus removal (mechanical with or without catheter-directed thrombolysis), and surgical embolectomy. CONCLUSION. This article will review the data available for treatment options and summarize the evidence-based guidelines on treatment of intermediate- or high-risk pulmonary embolism.

Interventional Therapies for Acute Pulmonary Embolism: Current Status and Principles for the Development of Novel Evidence: A Scientific Statement From the American Heart Association

Pulmonary embolism (PE) represents the third leading cause of cardiovascular mortality. The technological landscape for management of acute intermediate- and high-risk PE is rapidly evolving. Two interventional devices using pharmacomechanical means to recanalize the pulmonary arteries have recently been cleared by the US Food and Drug Administration for marketing, and several others are in various stages of development. The purpose of this document is to clarify the current state of endovascular interventional therapy for acute PE and to provide considerations for evidence development for new devices that will define which patients with PE would derive the greatest net benefit from their use in various clinical settings. First, definitions and limitations of commonly used risk stratification tools for PE are reviewed. An adjudication of risks and benefits of available interventional therapies for PE follows. Next, considerations for optimal future evidence development in this field are presented in the context of the current US regulatory framework. Finally, the document concludes with a discussion of the pros and cons of the rapidly expanding PE response team model of care delivery.

Definitions, adjudication, and reporting of pulmonary embolism-related death in clinical studies: A systematic review

BACKGROUND

Pulmonary embolism (PE)-related death is a component of the primary outcome in many venous thromboembolism (VTE) studies. The absence of a standardized definition for PE-related death hampers study outcome evaluation and between-study comparisons.

OBJECTIVES

To summarize definitions for PE-related death used in recent VTE studies and to assess the PE-related death rate.

PATIENTS/METHODS

A systematic literature search was conducted on 26 April 2018 from 1 January 2014 up to the search date in MEDLINE, Embase, and CENTRAL. Cohort studies and randomized trials in which PE-related death was included in the primary outcome were eligible. Screening of titles, abstracts, and full-text articles, and data extraction were independently performed in duplicate by two authors. Study outcomes included the definition for PE-related death, VTE case-fatality rate, and death due to PE rate. Descriptive statistics were used to analyze the data.

RESULTS

Of the 6807 identified citations, 83 studies were included of which 27% were randomized trials, 31% were prospective, and 42% retrospective cohort studies. Thirty-five studies (42%) had a central adjudication committee. Thirty-eight (46%) reported a definition for PE-related death of which the most frequently used components were "autopsy-confirmed PE" (50%), "objectively confirmed PE before death" (55%), and "unexplained death" (58%). Median VTE case-fatality rate was 1.8% (interquartile range, 0.0-13).

CONCLUSIONS

Only half of the included studies reported definitions for PE-related death, which were very heterogeneous. Case-fatality rate of VTE events varied widely across studies. Standardization of the definition and guidance on adjudication and reporting of PE-related death is needed.

Thrombolysis with reteplase in acute pulmonary embolism

Objective

Reteplase (recombinant plasminogen activator) is a mutant of alteplase. It has a longer half-life than its parent molecule and has shown better vessel patency rates in acute myocardial infarction. In this study, we analyzed the efficacy and safety of reteplase in acute pulmonary embolism (PE).

Methods

This observational study included patients with high- and intermediate-risk acute PE, presenting within 14 days of symptom onset. The patients were treated with reteplase, which was given in two bolus doses of 10 U each, 30 min apart, along with intravenous heparin. Patients with hemodynamic compromise (high-risk or massive PE) and normotensive patients with evidence of right ventricular (RV) dysfunction (intermediate-risk or submassive PE) on echocardiography or computed tomography were included in the study. The efficacy outcomes assessed were in-hospital death and improvement of RV function by echocardiography. The safety outcomes were major bleeding, minor bleeding, and ischemic or hemorrhagic stroke during hospitalization.

Results

Of the 40 patients included, 25% were classified as high risk with hemodynamic compromise and 75% were classified as intermediate risk. RV dysfunction was present in all the patients (100%). Concomitant lower extremity deep vein thrombosis was present in 55% of the patients. The mortality rate was 5%. There was significant improvement in RV function and reduction in pulmonary artery systolic pressure and tricuspid regurgitation severity. There was no major bleeding event or stroke, and 7.5% patients had minor extracranial bleeding.

Conclusions

Double-bolus reteplase given with heparin is effective in the treatment of high- and intermediate-risk PE, with minimal risk of bleeding.

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.

Pulmonary embolism critical care update: prognosis, treatment, and research gaps

PURPOSE OF REVIEW

We provide a timely update on treatment care issues facing clinicians and patients with acute pulmonary embolism accompanied by either right ventricular strain (sub-massive pulmonary embolism) or shock (massive pulmonary embolism).

RECENT FINDINGS

Care and research changes over the last several years have resulted in four important trends: more consensus and accuracy in the way acute pulmonary embolism severity is described and communicated among acute care clinicians and researchers, increased availability and use of risk prediction scoring systems, increased use of advanced invasive therapy in the setting of severe right ventricular dysfunction, and emergence of multidisciplinary pulmonary embolism response teams to guide standard care decision-making.

SUMMARY

Pulmonary embolism with shock should be treated with either systemic or catheter-based thrombolytic therapy in the absence of contraindications. Patients with sub-massive pulmonary embolism accompanied by right heart dysfunction who are treated with thrombolytic therapy likely will experience more rapid improvement in RV function and are less likely to progress to hemodynamic decompensation. This comes, however, with an increased risk of major bleeding. Our recommendation is to consider catheter-based or systemic fibrinolytic therapy in sub-massive pulmonary embolism cases where patients demonstrate high-risk features such as: severe RV strain on echo or CT, and importantly worsening over time trends in pulse, SBP, and oxygenation despite anticoagulation. Understanding the impact of advanced therapy beyond standard anticoagulation on patient-centered outcomes, such as functional status and quality of life represent a research knowledge gap.

Systemic Thrombolysis for Pulmonary Embolism: Evidence, Patient Selection, and Protocols for Management

Acute pulmonary embolism presents a clinical challenge for optimal risk stratification. Although associated with significant morbidity and mortality at the population level, the spectrum of presentation in an individual patient varies from mild symptoms to cardiac arrest. Treatment options include anticoagulation, systemic thrombolysis, catheter-based interventions, and surgical embolectomy. In this article, an attempt is made to optimally identify patients who, based on available evidence, may benefit from systemic thrombolytic therapy. The clinical efficacy of systemic thrombolysis must be balanced against increased risks of major bleeding and intracranial hemorrhage.

Improving fibrinolysis in venous thromboembolism: impact of fibrin structure

Introduction. Fibrinolysis is of key importance in maintaining vessel patency. Impaired fibrinolysis associated with more compact fibrin structure has been shown in patients with venous thromboembolism (VTE), including deep-vein thrombosis and pulmonary embolism (PE). Currently, recombinant or modified plasminogen activators are the only commonly available thrombolytic agents. However, they are fraught with side effects and suboptimal effectiveness. Areas covered. Based on the available literature, the current evidence linking fibrinolysis with VTE and potential therapeutic targets among fibrinolysis proteins are presented. Expert opinion. Prolonged clot lysis time has been reported as a new predictor of first-time and recurrent VTE, including PE. Anticoagulant therapy, including non-vitamin K antagonist oral anticoagulants, has a favorable impact on fibrinolysis in VTE patients. Several VTE risk factors are also related to lower efficiency of fibrinolysis and their treatment improve fibrinolysis, in part by alterations to fibrin properties. There is an increasing number of studies aiming at developing novel profibrinolytic therapeutic agents for treatment of VTE patients, mostly targeting the antifibrinolytic proteins, i.e. antiplasmin, plasminogen activator inhibitor-1 and thrombin-activatable fibrinolysis inhibitor.

Pulmonary embolism response teams: Purpose, evidence for efficacy, and future research directions

Pulmonary embolism (PE) is a major cause of morbidity and mortality in the United States. Although new therapeutic tools and strategies have recently been developed for the diagnosis and treatment of patients with PE, the outcomes for patients who present with massive or high-risk PE remain dismal. To address this crisis, pulmonary embolism response teams (PERTs) are being created around the world in an effort to immediately and simultaneously engage multiple specialists to determine the best course of action and coordinate the clinical care for patients with acute PE. The scope of this review is to describe the PERT model and purpose, present the structure and organization, examine the available evidence for efficacy and usefulness, and propose future directions for research that is needed to demonstrate the value of PERT and determine if this multidisciplinary approach represents a new standard of care.

Low-Dose Alteplase for the Treatment of Submassive Pulmonary Embolism: A Case Series

PURPOSE

Pulmonary embolism (PE) can lead to significant morbidity and mortality. Thrombolytics are currently approved for the treatment of massive PE; however, the CHEST guidelines recommend against systemic thrombolytic use in acute PE patients without hypotension, unless these patients deteriorate on anticoagulation alone. Several studies have demonstrated the effectiveness of thrombolysis in submassive PE; however, the full thrombolytic dose resulted in significantly increased risk of non-intracranial bleeding and hemorrhagic stroke. The MOPETT trial demonstrated that low-dose tissue plasminogen activator (tPA) significantly reduced the risk of pulmonary hypertension and recurrent PE compared to anticoagulation alone in submassive PE patients without any bleeding events.

SUMMARY

This case series highlights 5 patient cases utilizing low-dose tPA for submassive PE. All patients had successful resolution of their symptoms and improvement in vitals and laboratory values. Furthermore, no patient had any bleeding during or after tPA administration. Three patients showed improved right ventricle function and reduced or normal right ventricle size on echocardiogram after tPA administration.

CONCLUSION

The potential for low-dose tPA as a safe and efficacious treatment option for submassive PE is illustrated by this case series. However, larger, randomized controlled trials are needed to establish low-dose tPA as an accepted treatment modality.

Update on Thrombolytic Therapy in Acute Pulmonary Thromboembolism

Thrombolytic treatment accelerates the dissolution of thrombus in acute pulmonary thromboembolism (PTE) and is potentially a lifesaving treatment. High-risk PTE is the clearest indication for this therapy, and its use in intermediate-risk cases is still controversial. A PTE response team may enable a rapid and effective determination of risk and treatment in these controversial clinical cases. Approved thrombolytic agents for the PTE treatment are streptokinase, urokinase, and alteplase. Currently, the most widely used agent is alteplase. It has a short infusion time (2 h) and a rapid effect. Newer, unapproved agents for the PTE treatment are tenecteplase and reteplase. The active resolution of thrombus via thrombolytic agents improves rapidly pulmonary perfusion, hemodynamic defect, gas exchange, and right ventricular dysfunction. However, it is important to determine appropriate candidates carefully, to prevent hemorrhage, which is the most important side effect of these drugs. Catheter-directed thrombolysis seems to be an alternative in patients not eligible for systemic thrombolytic therapy.

Local Ultrasound-Facilitated Thrombolysis in High-Risk Pulmonary Embolism: First Dutch Experience

Purpose

To provide insight into the current use and results of ultrasound-facilitated catheter-directed thrombolysis (USAT) in patients with high-risk pulmonary embolism (PE).

Introduction

Systemic thrombolysis is an effective treatment for hemodynamically unstable, high-risk PE, but is associated with bleeding complications. USAT is thought to reduce bleeding and is therefore advocated in patients with high-risk PE and contraindications for systemic thrombolysis.

Methods

We conducted a retrospective cohort study of all patients who underwent USAT for high-risk PE in the Netherlands from 2010 to 2017. Characteristics and outcomes were analyzed. Primary outcomes were major (including intracranial and fatal) bleeding and all-cause mortality after 1 month. Secondary outcomes were all-cause mortality and recurrent venous thromboembolism within 3 months.

Results

33 patients underwent USAT for high-risk PE. Major bleeding occurred in 12 patients (36%, 95% CI 22–53), including 1 intracranial and 3 fatal bleeding. All-cause mortality after 1 month was 48% (16/33, 95% CI 31–66). All-cause mortality after 3 months was 50% (16/32, 95% CI 34–66), recurrent venous thromboembolism occurred in 1 patient (1/32, 3%, 95% CI 1–16).

Conclusions

This study was the first to describe characteristics and outcomes after USAT in a study population of patients with high-risk PE only, an understudied population. Although USAT is considered a relatively safe treatment option, our results illustrate that at least caution is needed in critically ill patients with high-risk PE. Further research in patients with high-risk PE is warranted to guide patient selection.

Preservation of Cardiopulmonary Function in Patients Treated with Ultrasound-Accelerated Thrombolysis in the Setting of Submassive Pulmonary Embolism

PURPOSE

To evaluate the clinical effectiveness of ultrasound-assisted thrombolysis (USAT) in resolution of right ventricular dysfunction (RVD), preservation of cardiopulmonary function, and quality of life (QoL) in patients with acute submassive pulmonary embolism (PE).

MATERIALS AND METHODS

A single-center prospective study of patients presenting with acute PE and signs of RVD, as determined by right ventricle-to-left ventricle diameter ratio (RV:LV) > 0.9 on computed tomographic angiography of the thorax, was performed. Patients underwent USAT with recombinant tissue plasminogen activator. Primary endpoints measured were RV:LV by echocardiogram at baseline presentation and at 72 hours and 90 days after treatment. Secondary endpoints were QoL scores assessed by SF-36 Health Surveys at baseline and at 90 days, cardiopulmonary exercise test (CPET) parameters at 90 days, and procedural outcomes, including response of pulmonary artery pressure (PAP) and procedural complications.

RESULTS

Twenty-five patients were treated between June 17, 2013, and September 15, 2014, with mean reduction of RV:LV by echocardiogram from 1.38 ± 0.28 at presentation to 0.92 ± 0.14 (P < .0001) at 72 hours and 0.84 ± 0.25 (P < .0001) at 90 days. SF-36 Health Survey scores demonstrated no long-term self-perceived adverse physical or mental effects as a result of PE. CPET parameters, including VO2_max, weight-adjusted VO2, VE/VCO2, and VD/VT demonstrated no pulmonary vascular impairment at 90 days. PAP significantly improved after USAT, with mean initial systolic pressure of 50.46 ± 13.98 mmHg reduced to 39.64 ± 8.66 mmHg (P = .0001). There were no deaths, recurrent venous thromboembolism, hemodynamic decompensation, or hemorrhage.

CONCLUSIONS

USAT resulted in significant reduction of RV:LV at 72 hours, which was preserved at 90 days. QoL and objective measures of cardiopulmonary function are preserved at 90 days in this population. Further studies with long-term follow-up are needed to determine the potential value of USAT for the prevention of post-PE syndrome in patients with submassive PE.

Changes in treatment and outcomes after creation of a pulmonary embolism response team (PERT), a 10-year analysis

Multidisciplinary pulmonary embolism response teams (PERTs) are being implemented to improve care of patients with life-threatening PE. We sought to determine how the creation of PERT affects treatment and outcomes of patients with serious PE. A pre- and post-intervention study was performed using an interrupted time series design, to compare patients with PE before (2006-2012) and after (2012-2016) implementation of PERT at a university hospital. T-tests, Chi square tests and logistic regression were used to compare outcomes, and multivariable regression were used to adjust for differences in PE severity. Two-sided p-value < 0.05 was considered significant. For the interrupted time-series analysis, data was divided into mutually exclusive 6-month time periods (11 pre- and 7 post-PERT). To examine changes in treatment and outcomes associated with PERT, slopes and change points were compared pre- and post-PERT. Two-hundred and twelve pre-PERT and 228 post-PERT patients were analyzed. Patient demographics were generally similar, though pre-PERT, PE were more likely to be low-risk (37% vs. 19%) while post-PERT, PE were more likely to be submassive (32% vs. 49%). More patients underwent catheter directed therapy (1% vs. 14%, p = < 0.0001) or any advanced therapy (19 [9%] vs. 44 [19%], p = 0.002) post PERT. Interrupted time series analysis demonstrated that this increase was sudden and coincident with implementation of PERT, and most noticeable among patients with submassive PE. There were no differences in major bleeding or mortality pre- and post-PERT. While the use of advanced therapies, particularly catheter-directed therapies, increased after creation of PERT, especially among patients with submassive PE, there was no apparent increase in bleeding.

Thrombolytic therapy for pulmonary embolism

BACKGROUND

Thrombolytic therapy 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 may 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 haemorrhage. This is the third update of the Cochrane review first published in 2006.

OBJECTIVES

To assess the effects of thrombolytic therapy for acute pulmonary embolism.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 16 April 2018. We undertook reference checking to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared thrombolytic therapy followed by heparin versus heparin alone, heparin plus placebo, or surgical intervention for 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 review authors (JY, QH) assessed the eligibility and quality of trials and extracted data. We calculated effect estimates using the odds ratio (OR) with 95% confidence interval (CI) or the mean difference (MD) with 95% CI. We assessed the quality of the evidence using GRADE criteria.

MAIN RESULTS

We identified no new studies for inclusion in this 2018 update. We included in the review 18 trials with a total of 2197 participants. We were not able to include one study in the meta-analysis because it provided no data that we could extract. Most of the studies carried a high risk of bias because of high or unclear risk related 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 (OR 0.57, 95% CI 0.37 to 0.87, 2167 participants, P = 0.01, low-quality evidence) and recurrence of PE (OR 0.51, 95% CI 0.29 to 0.89, 1898 participants, P = 0.02, low-quality evidence). Effects on mortality weakened when we excluded from analysis four studies at high risk of bias (OR 0.66, 95% CI 0.42 to 1.06, 2054 participants, P = 0.08). The incidence of major and minor haemorrhagic events was higher in the thrombolytics group than in the control group (OR 2.90, 95% CI 1.95 to 4.31, 1897 participants, P < 0.001, low-quality evidence; OR 3.09, 95% CI 1.58 to 6.06, 1553 participants, P = 0.001, very low-quality evidence, respectively). We downgraded the quality of the evidence to low or very low because of design limitations, potential influence of pharmaceutical companies, and small sample sizes. Length of hospital stay (mean difference (MD) -0.89, 95% CI -3.13 to 1.34) and quality of life were similar between the two treatment groups. 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 the small number of participants involved warrant caution when results are interpreted. Similarily, fewer participants from the thrombolytics group required escalation of treatment. None of the included studies reported on post-thrombotic syndrome or compared the costs of different treatments.

AUTHORS' CONCLUSIONS

Low-quality evidence suggests that thrombolytics reduce death following acute pulmonary embolism compared with heparin. The included studies used a variety of thrombolytic drugs. Thrombolytic therapy may be helpful in reducing the recurrence of pulmonary emboli but may cause major and minor haemorrhagic events and stroke. More high-quality, blinded randomised controlled trials assessing safety and cost-effectiveness of therapies for pulmonary embolism are required.

Incomplete echocardiographic recovery at 6 months predicts long-term sequelae after intermediate-risk pulmonary embolism. A post-hoc analysis of the Pulmonary Embolism Thrombolysis (PEITHO) trial

Introduction

Symptoms and functional limitation are frequently reported by survivors of acute pulmonary embolism (PE). However, current guidelines provide no specific recommendations on which patients should be followed after acute PE, when follow-up should be performed, and which tests it should include. Definition and classification of late PE sequelae are evolving, and their predictors remain to be determined.

Methods

In a post hoc analysis of the Pulmonary Embolism Thrombolysis (PEITHO) trial, we focused on 219 survivors of acute intermediate-risk PE with clinical and echocardiographic follow-up 6 months after randomisation as well as over the long term (median, 3 years after acute PE). The primary outcome was a composite of (1) confirmed chronic thromboembolic pulmonary hypertension (CTEPH) or (2) ‘post-PE impairment’ (PPEI), defined by echocardiographic findings indicating an intermediate or high probability of pulmonary hypertension along with New York Heart Association functional class II–IV.

Results

Confirmed CTEPH or PPEI occurred in 29 (13.2%) patients, (6 with CTEPH and 23 with PPEI). A history of chronic heart failure at baseline and incomplete or absent recovery of echocardiographic parameters at 6 months predicted CTEPH or PPEI at long-term follow-up.

Conclusions

CTEPH or PPEI occurs in almost one out of seven patients after acute intermediate-risk PE. Six-month echocardiographic follow-up may be useful for timely detection of late sequelae.

Treatment of submassive and massive pulmonary embolism: a clinical practice survey from the second annual meeting of the Pulmonary Embolism Response Team Consortium

There is a paucity of robust clinical trial data to guide the treatment of acute pulmonary embolism (PE) thus the clinical guidelines rely heavily on expert opinion. Pulmonary Embolism Response Teams (PERT) have been developed to streamline the care of patients with acute PE. We conducted a survey among 100 experts in the field of PE during the second annual meeting of the PERT Consortium. Respondents were queried with respect to their demographic information, clinical practice questions and clinical vignettes. Clinical practice questions were focused questions about the risk stratification and treatment of patients with acute submassive PE, anticoagulation strategies for patients receiving thrombolysis and the use of inferior vena cava filters. Clinical vignettes were designed to assess participants' preferred choice of treatment for a variety of commonly encountered clinical scenarios. Among physicians affiliated with a PERT, there is overall agreement with regards to the criteria used for risk classification of patients with PE and its application to patients in the provided clinical vignettes. In contrast, there is substantial variability in the treatment strategies of patients presenting with commonly encountered clinical scenarios. The results of this survey highlight the need for more clinical trial data along with accepted algorithms for treatment of acute PE. In the absence of this, PERTs can facilitate multidisciplinary discussions in order to standardize treatment and provide evidence-based therapies to patients with acute PE.

Pulmonary Embolism: Contemporary Medical Management and Future Perspectives

Pulmonary embolism (PE) contributes substantially to the global disease burden. A key determinant of early adverse outcomes is the presence (and severity) of right ventricular dysfunction. Consequently, risk-adapted management strategies continue to evolve, tailoring acute treatment to the patients' clinical presentation, hemodynamic status, imaging and biochemical markers, and comorbidity. For subjects with hemodynamic instability or 'high-risk' PE, immediate systemic reperfusion treatment with intravenous thrombolysis is indicated; emerging approaches such as catheter-directed pharmacomechanical reperfusion might help to minimize the bleeding risk. Currently, direct, non-vitamin K-dependent oral anticoagulants are the mainstay of treatment for acute PE. They have been shown to simplify initial and extended anticoagulation regimens while reducing the bleeding risk compared to vitamin K antagonists. (This is a review article based on the invited lecture of the 37th Annual Meeting of Japanese Society of Phlebology.).