A controlled clinical trial of streptokinase and heparin in the treatment of major pulmonary embolism

Safety and efficacy of clot-dissolving therapies for submassive pulmonary embolism: A network meta-analysis of randomized controlled trials

BACKGROUND

Acute pulmonary embolism (PE) is a serious condition that needs quick and effective treatment. Anticoagulation therapy is the usual care for most PE patients but may not work well for higher-risk ones. Thrombolysis breaks the clot and improves blood flow. It can be given systemically or locally. Ultrasound-assisted catheter-directed thrombolysis (USAT) is a new technique that boosts clot-busting drugs. This network meta-analysis compares death, bleeding, and benefits of four treatments in acute submassive PE.

METHODS

We comprehensively searched relevant databases up to July 2023 for RCTs. The outcomes encompassed all-cause mortality, major and minor bleeding, PE recurrence, and hospital stay duration. Bayesian network meta-analysis computed odds ratios (OR) and 95 % CI estimates.

RESULTS

In this network meta-analysis of 23 RCTs involving 2521 PE patients, we found that SCDT had the most favorable performance for mortality, as it had the lowest odds ratio (OR) among the four interventions (OR 5.41e-42; 95 % CI, 5.68e-97, 1.37e-07). USAT had the worst performance for major bleeding, as it had the highest OR among the four interventions (OR 4.73e+04; 95 % CI, 1.65, 9.16e+13). SCDT also had the best performance for minor bleeding, as it had the lowest OR among the four interventions (OR 5.68e-11; 95 % CI, 4.97e-25, 0.386).

CONCLUSION

Our meta-analysis suggests that SCDT is the most effective treatment intervention in improving the risks of All-cause mortality and bleeding. Thrombolytic therapy helps in improving endpoints including the risk of PE recurrence and the duration of hospital stay.

A decisive lifesaving tool in submassive pulmonary embolism: Bedside echocardiography

Key Clinical Message

Immediate thrombolysis in submassive pulmonary embolism on the basis of bedside echocardiography can be a lifesaving decision in areas where computed tomography (CT) pulmonary angiogram is not readily available.

Abstract

Bedside echocardiography can be a rapid diagnostic and decision-making tool for immediate thrombolysis in submassive pulmonary embolism with evidence of progressively failing ventricles. We report a case of submassive pulmonary embolism in a 26-year-old male under testosterone replacement therapy, who was successfully thrombolyzed based on bedside echocardiography findings.

Fibrin and Fibrinolytic Enzyme Cascade in Thrombosis: Unravelling the Role

Blood clot formation in blood vessels (thrombosis) is a major cause of life-threatening cardiovascular diseases. These clots are formed by αA-, βB-, and ϒ-peptide chains of fibrinogen joined together by isopeptide bonds with the help of blood coagulation factor XIIIa. These clot structures are altered by various factors such as thrombin, platelets, transglutaminase, DNA, histones, and red blood cells. Various factors are used to dissolve the blood clot, such as anticoagulant agents, antiplatelets drugs, fibrinolytic enzymes, and surgical operations. Fibrinolytic enzymes are produced by microorganisms (bacteria, fungi, etc.): streptokinase of Streptococcus hemolyticus, nattokinase of Bacillus subtilis YF 38, bafibrinase of Bacillus sp. AS-S20-I, longolytin of Arthrobotrys longa, versiase of Aspergillus versicolor ZLH-1, etc. They act as a thrombolytic agent by either enhancing the production of plasminogen activators (tissue or urokinase types), which convert inactive plasminogen to active plasmin, or acting as plasmin-like proteins themselves, forming fibrin degradation products which cause normal blood flow again in blood vessels. Fibrinolytic enzymes may be classified in two groups, as serine proteases and metalloproteases, based on their catalytic properties, consisting of a catalytic triad responsible for their fibrinolytic activity having different physiochemical properties (such as molecular weight, pH, and temperature). The analysis of fibrinolysis helps to detect hyperfibrinolysis (menorrhagia, renal failure, etc.) and hypofibrinolysis (diabetes, obesity, etc.) with the help of various fibrinolytic assays such as a fibrin plate assay, fibrin microplate assay, the viscoelastic method, etc. These fibrinolytic activities serve as a key aspect in the recognition of numerous cardiovascular diseases and can be easily produced on a large scale with a short generation time by microbes and are less expensive.

An Update on the Management of Acute High-Risk Pulmonary Embolism

Hemodynamic instability and right ventricular (RV) dysfunction are the key determinants of short-term prognosis in patients with acute pulmonary embolism (PE). High-risk PE encompasses a wide spectrum of clinical situations from sustained hypotension to cardiac arrest. Early recognition and treatment tailored to each individual are crucial. Systemic fibrinolysis is the first-line pulmonary reperfusion therapy to rapidly reverse RV overload and hemodynamic collapse, at the cost of a significant rate of bleeding. Catheter-directed pharmacological and mechanical techniques ensure swift recovery of echocardiographic parameters and may possess a better safety profile than systemic thrombolysis. Further clinical studies are mandatory to clarify which pulmonary reperfusion strategy may improve early clinical outcomes and fill existing gaps in the evidence.

Association Between the Use of Pre- and Post-thrombolysis Anticoagulation With All-Cause Mortality and Major Bleeding in Patients With Pulmonary Embolism

Objective

To explore the comparative clinical efficacy and safety outcomes of anticoagulation before (pre-) or following (post-) thrombolytic therapy in systemic thrombolytic therapy for pulmonary embolism (PE).

Methods

PubMed, the Cochrane Library, EMBASE, EBSCO, Web of Science, and CINAHL databases were searched from inception through 1 May 2021. All randomized clinical trials comparing systemic thrombolytic therapy vs. anticoagulation alone in patients with PE and those that were written in English were eligible. The primary efficacy and safety outcomes were all-cause mortality and major bleeding, respectively. Odds ratios (OR) estimates and associated 95% confidence intervals (CIs) were calculated. A Bayesian network analysis was performed using R studio software, and then the efficacy and safety rankings were derived.

Results

This network meta-analysis enrolled 15 trials randomizing 2,076 patients. According to the plot rankings, the anticoagulant therapy was the best in terms of major bleeding, and the post-thrombolysis anticoagulation was the best in terms of all-cause mortality. Taking major bleeding and all-cause mortality into consideration, the most safe–effective treatment was the post-thrombolysis anticoagulation in patients who needed thrombolytic therapy. The net clinical benefit analysis comparing associated ICH benefits vs. mortality risks of post-thrombolysis anticoagulation demonstrated a net clinical benefit of 1.74%.

Conclusion

The systemic thrombolysis followed by anticoagulation had a better advantage in all-cause mortality and major bleeding than the systemic thrombolysis before anticoagulation. The adjuvant anticoagulation treatment of systemic thrombolytic therapy should be optimized.

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.

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.

Treatment of a Child With Submassive Pulmonary Embolism Associated With Hereditary Spherocytosis Using Ultrasound-Assisted Catheter-Directed Thrombolysis

Background: The clinical presentation of hereditary spherocytosis varies from no symptoms to severe hemolytic anemia requiring splenectomy. Splenectomy imposes the risk of hypercoagulability and acute pulmonary embolism. Catheter-directed thrombolysis is an established treatment for submassive pulmonary embolism in adults. However, the literature regarding its use in children is limited. Case Report: We present the case of a 12-year-old male with hereditary spherocytosis who was diagnosed with pulmonary embolism and successfully treated with catheter-directed thrombolysis. The patient was initially treated with 10.5 mg of recombinant tissue plasminogen activator (r-tPA) delivered over 8 hours. However, because of minimal clinical and hemodynamic improvement, a second course of thrombolytic was administered for an additional 24 hours (25 mg of r-tPA), and the treatment resulted in marked clinical and hemodynamic improvement. Clot resolution was confirmed via angiography. The patient was discharged on enoxaparin and with regular follow-up. One year later, the patient was asymptomatic on enoxaparin. Conclusion: This case demonstrates that catheter-based treatment of submassive pulmonary embolism restores hemodynamic stability and thus is an alternative to surgery or systemic thrombolysis, even in the pediatric setting. While catheter-directed thrombolysis is a safe and effective alternative to systemic thrombolysis, further research is needed to establish appropriate dosing and indications in the adolescent population.

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.

Understanding haemorrhagic risk following thrombolytic therapy in patients with intermediate-risk and high-risk pulmonary embolism: a hypothesis paper

While systemic intravenous thrombolysis decreases mortality in patients with high-risk pulmonary embolism (PE), it clearly increases haemorrhagic risk. There are many contraindications to thrombolysis, and efforts should aim at selecting those patients who will benefit most, without suffering complications. The current review summarises the evidence for the use of thrombolytic therapy in PE. It clarifies the pathophysiological mechanisms in PE and acute cor pulmonale that increase the risk of bleeding following thrombolysis. It discusses future management challenges, namely tailored drug administration, new treatment monitoring techniques and catheter-directed thrombolysis.

From Acute to Chronic Thromboembolic Disease

After achievement of adequate anticoagulation, the natural history of acute pulmonary emboli ranges from near total resolution of vascular perfusion to long-term persistence of hemodynamically consequential residual perfusion defects. The persistence of perfusion defects is necessary, but not sufficient, for the development of chronic thromboembolic pulmonary hypertension (CTEPH). Approximately 30% of patients have persistent defects after 6 months of anticoagulation, but only 10% of those with persistent defects subsequently develop CTEPH. A number of clinical risk factors including increasing age, delay in anticoagulation from symptom onset, and the size of the initial thrombus have been associated with the persistence of perfusion defects. Likewise, a number of cellular and molecular pathways have been implicated in the failure of thrombus resolution, including impaired fibrinolysis, altered fibrinogen structure and function, increased local or systemic inflammation, and remodeling of the embolic material by neovascularization. Treatment with fibrinolytic agents at the time of initial presentation has not clearly improved the frequency or degree of recovery of pulmonary vascular perfusion. A better understanding of the interplay between clinical risk factors and pathogenic mechanisms may enhance the ability to prevent and treat CTEPH in the future.

Can thrombus age guide thrombolytic therapy?

Venous thrombosis (VT) is a common yet complex clinical condition that has shown minimal alteration in clinical management for decades. It is well known that thrombus evolves structurally over time, with complex changes resulting from the interplay between coagulation factors, cytokines, leukocytes and a myriad of other factors. Our current treatment options are most effective in the acute thrombus, which is composed predominantly of a loose mesh of fibrin and red blood cells (RBCs), making current anticoagulation therapies and thrombolytics quite effective in treatment. Later stages of thrombus are more cellular containing leukocytes, and develop a fibrotic collagenous framework that is more resistant to our current treatments. Understanding the biology of an evolving thrombus will allow us to tailor our treatment and optimize outcomes, as well as focus on novel therapies for the treatment of chronic thrombus. Given the morbidity and mortality of both post thrombotic syndrome (PTS) in patients with deep VT, as well as chronic thromboembolic pulmonary hypertension (CTEPH) in patients with pulmonary embolism (PE), new and innovative therapies must continue to be explored to help prevent these potentially devastating conditions.

Efficacy and safety outcomes of recanalisation procedures in patients with acute symptomatic pulmonary embolism: systematic review and network meta-analysis

Background

We aimed to review the efficacy and safety of recanalisation procedures for the treatment of PE.

Methods

We searched PubMed, the Cochrane Library, EMBASE, EBSCO, Web of Science and CINAHL databases from inception through 31 July 2015 and included randomised clinical trials that compared the effect of a recanalisation procedure versus each other or anticoagulant therapy in patients diagnosed with PE. We used network meta-analysis and multivariate random-effects meta-regression to estimate pooled differences between each intervention and meta-regression to assess the association between trial characteristics and the reported effects of recanalisation procedures versus anticoagulation.

Results

For all-cause mortality, there were no significant differences in event rates between any of the recanalisation procedures and anticoagulant treatment (full-dose thrombolysis: OR 0.60; 95% CI0.36 to 1.01; low-dose thrombolysis: 0.47; 95% CI 0.14 to 1.59; and catheter-associated thrombolysis: 0.31; 95% CI 0.01 to 7.96). Full-dose thrombolysis increased the risk of major bleeding (2.00; 95% CI 1.06 to 3.78) compared with anticoagulation. Catheter-directed thrombolysis was associated with the lowest probability of dying (surface under the cumulative ranking curve (SUCRA), 0.67), followed by low-dose thrombolysis (SUCRA, 0.66) and full-dose thrombolysis (SUCRA, 0.55). Similarly, low-dose thrombolysis was associated with the lowest probability of major bleeding (SUCRA, 0.61), followed by catheter-directed thrombolysis (SUCRA, 0.54) and full-dose thrombolysis (SUCRA, 0.17). The results were similar in sensitivity analyses based on restricting only to studies in haemodynamically stable patients with PE.

Conclusions

In the treatment of PE, recanalisation procedures do not seem to offer a clear advantage compared with standard anticoagulation. Low-dose thrombolysis was associated with the lowest probability of dying and bleeding.

Trial registration number

PROSPERO CRD42015024670.

Fibrinolysis for Acute Care of Pulmonary Embolism in the Intermediate Risk Patient

Controversy over the role of fibrinolysis in patients with intermediate-risk pulmonary embolism (PE) has persisted because of the lack of adequately sized trials. The PEITHO study now allows a more precise estimate of the risk to benefit ratio of fibrinolysis in these patients. This trial enrolled patients with intermediate-risk PE who were randomized to receive heparin with either tenecteplase or placebo. Fibrinolysis was associated with a significant reduction in the combined end-point of death or hemodynamic decompensation, but also with a significant increase in the risk of major bleeding. The primary efficacy end-point occurred in 2.6 % of the patients in the tenecteplase group and in 5.6 % of the patients in the placebo group (OR, 0.44; 95 % CI, 0.23 to 0.87), conversely, major extracranial bleeding occurred in 6.3 % and 1.2 % in the tenecteplase and placebo groups, respectively (OR, 5.55; 95 % CI, 2.3 to 13.39) and stroke occurred in 2.4 % and in 0.2 % of the patients in the tenecteplase group and in the placebo group, respectively (OR, 12.10; 95 % CI, 1.57 to 93.39). No difference was observed for the risk of death alone and the risk of full-dose thrombolytic therapy outweighs its benefit in patients with intermediate-risk PE. Recent meta-analyses suggest that fibrinolysis may be associated with a slight reduction in overall mortality offset by an increase in major bleeding. Two pilot studies suggest that a reduced dose of fibrinolysis may produce significant hemodynamic improvement with a low risk of major bleeding. These options need to be evaluated in larger studies including patients with a higher risk of adverse outcome than those included in the PEITHO study.

Double Bolus Thrombolysis for Suspected Massive Pulmonary Embolism during Cardiac Arrest

More than 70% of cardiac arrest cases are caused by acute myocardial infarction (AMI) or pulmonary embolism (PE). Although thrombolytic therapy is a recognised therapy for both AMI and PE, its indiscriminate use is not routinely recommended during cardiopulmonary resuscitation (CPR). We present a case describing the successful use of double dose thrombolysis during cardiac arrest caused by pulmonary embolism. Notwithstanding the relative lack of high-level evidence, this case suggests a scenario in which recombinant tissue Plasminogen Activator (rtPA) may be beneficial in cardiac arrest. In addition to the strong clinical suspicion of pulmonary embolism as the causative agent of the patient's cardiac arrest, the extremely low end-tidal CO2 suggested a massive PE. The absence of dilatation of the right heart on subxiphoid ultrasound argued against the diagnosis of PE, but not conclusively so. In the context of the circulatory collapse induced by cardiac arrest, this aspect was relegated in terms of importance. The second dose of rtPA utilised in this case resulted in return of spontaneous circulation (ROSC) and did not result in haemorrhage or an adverse effect.

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.

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.

Systemic thrombolytic therapy for acute pulmonary embolism: a systematic review and meta-analysis

AIM

Thrombolytic therapy induces faster clot dissolution than anticoagulation in patients with acute pulmonary embolism (PE) but is associated with an increased risk of haemorrhage. We reviewed the risks and benefits of thrombolytic therapy in the management of patients with acute PE.

METHODS AND RESULTS

We systematically reviewed randomized controlled studies comparing systemic thrombolytic therapy plus anticoagulation with anticoagulation alone in patients with acute PE. Fifteen trials involving 2057 patients were included in our meta-analysis. Compared with heparin, thrombolytic therapy was associated with a significant reduction of overall mortality (OR; 0.59, 95% CI: 0.36-0.96). This reduction was not statistically significant after exclusion of studies including high-risk PE (OR; 0.64, 95% CI: 0.35-1.17). Thrombolytic therapy was associated with a significant reduction in the combined endpoint of death or treatment escalation (OR: 0.34, 95% CI: 0.22-0.53), PE-related mortality (OR: 0.29; 95% CI: 0.14-0.60) and PE recurrence (OR: 0.50; 95% CI: 0.27-0.94). Major haemorrhage (OR; 2.91, 95% CI: 1.95-4.36) and fatal or intracranial bleeding (OR: 3.18, 95% CI: 1.25-8.11) were significantly more frequent among patients receiving thrombolysis.

CONCLUSIONS

Thrombolytic therapy reduces total mortality, PE recurrence, and PE-related mortality in patients with acute PE. The decrease in overall mortality is, however, not significant in haemodynamically stable patients with acute PE. Thrombolytic therapy is associated with an increase of major and fatal or intracranial haemorrhage.

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

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

Recombinant tissue plasminogen activator for hemodynamically stable patients experiencing an acute pulmonary embolism: a meta-analysis

BACKGROUND

The role of thrombolytic therapy for the initial treatment of hemodynamically stable patients experiencing an acute pulmonary embolism remains controversial.

METHODS AND RESULTS

We performed a meta-analysis of randomized trials comparing between administration of recombinant tissue plasminogen activator (rt-PA) and heparin in hemodynamically stable patients experiencing an acute pulmonary embolism. Seven trials, involving 594 patients, were included in this meta-analysis. Compared with heparin, rt-PA was associated with a non-significant reduction in death (2.75% versus 3.96%; RR 0.69, 95% CI 0.31-1.52, P for heterogeneity=0.520) and recurrent pulmonary embolism (2.13% versus 3.34%; RR 0.70, 95% CI 0.28-1.73), and a non-significant increase in major bleeding (5.15% versus 4.29%; RR 1.06, 95% CI 0.520-2.150). Similar results were found based on a subgroup analysis of patients displaying echocardiographic evidence of right ventricular dysfunction (RVD). In contrast, rt-PA treatment was associated with a significant reduction in escalation of care in trials that also enrolled patients displaying RVD compared with heparin treatment (6.56% versus 19.7%; RR 0.34, 95% CI 0.20-0.65).

CONCLUSION

The currently available data provide no evidence for a benefit of administration of rt-PA compared with heparin for the initial treatment of hemodynamically stable patients experiencing an acute pulmonary embolism. However, rt-PA is partially beneficial specifically among patients displaying RVD.

Thrombolytic and anticoagulant therapy for acute submassive pulmonary embolism

This study aimed to compare the efficacy and safety of thrombolytic and anticoagulant therapy for acute submassive pulmonary embolism (PE). A retrospective evaluation was performed on 25 consecutive inpatients with acute submassive PE treated by thrombolytic therapy and 25 earlier consecutive inpatients with acute submassive PE treated by anticoagulant therapy. No statistically significant difference in clinical curative effect was identified between the thrombolysis and anticoagulation groups (P>0.05). Following 24 h of therapy, the improvement rates of dyspnea and revascularization in the thrombolysis group achieved statistical significance compared with those of the anticoagulation group (P<0.01 for each). The PO₂ level of the thrombolysis group (81.18±5.66 mmHg) was notably higher than that of the anticoagulation group and the difference was statistically significant (P<0.01). The pulmonary arterial pressures of the thrombolysis group (51.21±6.86 mmHg) were significantly lower than those of the anticoagulation group (60.64±5.17 mmHg) (P<0.01). Furthermore, the difference between the hemorrhage rates of the two groups was statistically significant (P<0.05). Thrombolysis was shown to rapidly relieve dyspnea, reduce pulmonary arterial pressure and revascularize the embolized blood vessels. However, the hemorrhage rate of the thrombolysis group was higher than that of the anticoagulation group. The overall efficacies and fatality rates of the thrombolysis and anticoagulation groups were similar.

Massive pulmonary embolism

Massive pulmonary embolism (PE) is a potentially lethal condition, with death usually caused by right ventricular (RV) failure and cardiogenic shock. Systemic thrombolysis (unless contraindicated) is recommended as the first-line treatment of massive PE to decrease the thromboembolic burden on the RV and increase pulmonary perfusion. Surgical pulmonary embolectomy or catheter-directed thrombectomy should be considered in patients with contraindications to fibrinolysis, or those with persistent hemodynamic compromise or RV dysfunction despite fibrinolytic therapy. Critical care management predominantly involves supporting the RV, by optimizing preload, RV contractility, and coronary perfusion pressure and minimizing afterload. Despite these interventions, mortality remains high.

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

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

Pulmonary embolism

Pulmonary embolism (PE) remains one of the most challenging medical diseases in the emergency department. PE is a potentially life threatening diagnosis that is seen in patients with chest pain and/or dyspnea but can span the clinical spectrum of medical presentations. In addition, it does not have any particular clinical feature, laboratory test, or diagnostic modality that can independently and confidently exclude its possibility. This article offers a review of PE in the emergency department. It emphasizes the appropriate determination of pretest probability, the approach to diagnosis and management, and special considerations related to pregnancy and radiation exposure.

Thrombolytic therapy in unstable patients with acute pulmonary embolism: saves lives but underused

BACKGROUND

Data are sparse and inconsistent regarding whether thrombolytic therapy reduces case fatality rate in unstable patients with acute pulmonary embolism. We tested the hypothesis that thrombolytic therapy reduces case fatality rate in such patients.

METHODS

In-hospital all-cause case fatality rate according to treatment was determined in unstable patients with pulmonary embolism who were discharged from short-stay hospitals throughout the United States from 1999 to 2008 by using data from the Nationwide Inpatient Sample. Unstable patients were in shock or ventilator dependent.

RESULTS

Among unstable patients with pulmonary embolism, 21,390 of 72,230 (30%) received thrombolytic therapy. In-hospital all-cause case fatality rate in unstable patients with thrombolytic therapy was 3105 of 21,390 (15%) versus 23,820 of 50,840 (47%) without thrombolytic therapy (P<.0001). All-cause case fatality rate in unstable patients with thrombolytic therapy plus a vena cava filter was 505 of 6630 (7.6%) versus 4260 of 12,850 (33%) with a filter alone (P<.0001). Case fatality rate attributable to pulmonary embolism in unstable patients was 820 of 9810 (8.4%) with thrombolytic therapy versus 1080 of 2600 (42%) with no thrombolytic therapy (P<.0001). Case fatality rate attributable to pulmonary embolism in unstable patients with thrombolytic therapy plus vena cava filter was 70 of 2590 (2.7%) versus 160 of 600 (27%) with a filter alone (P<.0001).

CONCLUSION

In-hospital all-cause case fatality rate and case fatality rate attributable to pulmonary embolism in unstable patients was lower in those who received thrombolytic therapy. Thrombolytic therapy resulted in a lower case fatality rate than using vena cava filters alone, and the combination resulted in an even lower case fatality rate. Thrombolytic therapy in combination with a vena cava filter in unstable patients with acute pulmonary embolism seems indicated.

Mortality risk assessment and the role of thrombolysis in pulmonary embolism

Acute venous thromboembolism remains a frequent disease, with an incidence ranging between 23 and 69 cases per 100,000 population per year. Of these patients, approximately one-third present with clinical symptoms of acute pulmonary embolism (PE) and two-thirds with deep venous thrombosis (DVT). Recent registries and cohort studies suggest that approximately 10% of all patients with acute PE die during the first 1 to 3 months after diagnosis. Overall, 1% of all patients admitted to hospitals die of acute PE, and 10% of all hospital deaths are PE-related. These facts emphasize the need to better implement our knowledge on the pathophysiology of the disease, recognize the determinants of death or major adverse events in the early phase of acute PE, and most importantly, identify those patients who necessitate prompt medical, surgical, or interventional treatment to restore the patency of the pulmonary vasculature.

Antithrombotic therapy for VTE disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This article addresses the treatment of VTE disease.

METHODS

We generated strong (Grade 1) and weak (Grade 2) recommendations based on high-quality (Grade A), moderate-quality (Grade B), and low-quality (Grade C) evidence.

RESULTS

For acute DVT or pulmonary embolism (PE), we recommend initial parenteral anticoagulant therapy (Grade 1B) or anticoagulation with rivaroxaban. We suggest low-molecular-weight heparin (LMWH) or fondaparinux over IV unfractionated heparin (Grade 2C) or subcutaneous unfractionated heparin (Grade 2B). We suggest thrombolytic therapy for PE with hypotension (Grade 2C). For proximal DVT or PE, we recommend treatment of 3 months over shorter periods (Grade 1B). For a first proximal DVT or PE that is provoked by surgery or by a nonsurgical transient risk factor, we recommend 3 months of therapy (Grade 1B; Grade 2B if provoked by a nonsurgical risk factor and low or moderate bleeding risk); that is unprovoked, we suggest extended therapy if bleeding risk is low or moderate (Grade 2B) and recommend 3 months of therapy if bleeding risk is high (Grade 1B); and that is associated with active cancer, we recommend extended therapy (Grade 1B; Grade 2B if high bleeding risk) and suggest LMWH over vitamin K antagonists (Grade 2B). We suggest vitamin K antagonists or LMWH over dabigatran or rivaroxaban (Grade 2B). We suggest compression stockings to prevent the postthrombotic syndrome (Grade 2B). For extensive superficial vein thrombosis, we suggest prophylactic-dose fondaparinux or LMWH over no anticoagulation (Grade 2B), and suggest fondaparinux over LMWH (Grade 2C).

CONCLUSION

Strong recommendations apply to most patients, whereas weak recommendations are sensitive to differences among patients, including their preferences.

Current status and trends in the treatment of acute pulmonary thromboembolism

Untreated acute pulmonary thromboembolism (APTE) is associated with high mortality, which is reduced by prompt treatment. Anticoagulation is fundamental in the treatment of APTE and should be initiated from suspicion. The efficacy and safety of novel anticoagulant drugs, such as oral anti-Xa and anti-IIa inhibitors, are topics in the treatment of APTE and are now under investigation. Thrombolytic therapy is a widely accepted treatment strategy for massive APTE, but its use for submassive APTE is controversial. Catheter intervention, percutaneous cardiopulmonary support and surgical embolectomy are also necessary and effective for some patients with APTE. A retrievable inferior vena cava filter is preferred for transient protection against APTE. Some studies have demonstrated the feasibility of outpatient treatment in patients with APTE after risk stratification.

Critical issues in the evaluation and management of adult patients presenting to the emergency department with suspected pulmonary embolism

This clinical policy from the American College of Emergency Physicians is the revision of a 2003 clinical policy on the evaluation and management of adult patients presenting with suspected pulmonary embolism (PE).(1) A writing subcommittee reviewed the literature to derive evidence-based recommendations to help clinicians answer the following critical questions: (1) Do objective criteria provide improved risk stratification over gestalt clinical assessment in the evaluation of patients with possible PE? (2) What is the utility of the Pulmonary Embolism Rule-out Criteria (PERC) in the evaluation of patients with suspected PE? (3)What is the role of quantitative D-dimer testing in the exclusion of PE? (4) What is the role of computed tomography pulmonary angiogram of the chest as the sole diagnostic test in the exclusion of PE? (5) What is the role of venous imaging in the evaluation of patients with suspected PE? (6) What are the indications for thrombolytic therapy in patients with PE? Evidence was graded and recommendations were given based on the strength of the available data in the medical literature.

Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: a scientific statement from the American Heart Association

Venous thromboembolism (VTE) is responsible for the hospitalization of >250 000 Americans annually and represents a significant risk for morbidity and mortality. Despite the publication of evidence-based clinical practice guidelines to aid in the management of VTE in its acute and chronic forms, the clinician is frequently confronted with manifestations of VTE for which data are sparse and optimal management is unclear. In particular, the optimal use of advanced therapies for acute VTE, including thrombolysis and catheter-based therapies, remains uncertain. This report addresses the management of massive and submassive pulmonary embolism (PE), iliofemoral deep vein thrombosis (IFDVT),and chronic thromboembolic pulmonary hypertension (CTEPH). The goal is to provide practical advice to enable the busy clinician to optimize the management of patients with these severe manifestations of VTE. Although this document makes recommendations for management, optimal medical decisions must incorporate other factors, including patient wishes, quality of life, and life expectancy based on age and comorbidities. The appropriateness of these recommendations for a specific patient may vary depending on these factors and will be best judged by the bedside clinician.

Mortality risk assessment and the role of thrombolysis in pulmonary embolism

Acute venous thromboembolism remains a frequent disease, with an incidence ranging between 23 and 69 cases per 100,000 population per year. Of these patients, approximately one-third present with clinical symptoms of acute pulmonary embolism (PE) and two-thirds with deep venous thrombosis (DVT). Recent registries and cohort studies suggest that approximately 10% of all patients with acute PE die during the first 1 to 3 months after diagnosis. Overall, 1% of all patients admitted to hospitals die of acute PE, and 10% of all hospital deaths are PE-related. These facts emphasize the need to better implement our knowledge on the pathophysiology of the disease, recognize the determinants of death or major adverse events in the early phase of acute PE, and most importantly, identify those patients who necessitate prompt medical, surgical, or interventional treatment to restore the patency of the pulmonary vasculature.

Adverse drug events associated with disorders of coagulation

Disorders of coagulation are common adverse drug events encountered in critically ill patients and present a serious concern for intensive care unit (ICU) clinicians. Dosing strategies for medications used in the ICU are typically developed for use in noncritically ill patients and, therefore, do not account for the altered pharmacokinetic and pharmacodynamic properties encountered in the critically ill as well as the increased potential for drug-drug interactions, given the far greater number of medications ordered. This substantially increases the risk for coagulation-related adverse reactions, such as a bleeding or prothrombotic events. Although many medications used in the ICU have the potential to cause coagulation disorders, the exact incidence will vary based on the specific medication, dose, concomitant drug therapy, ICU setting, and patient-specific comorbidities. Clinicians must strongly consider these factors when evaluating the risk/benefit ratio for a particular therapy. This review surveys recent literature documenting the risk for adverse drug reactions specific to bleeding and/or clotting with commonly used medications in the ICU.

Pulmonary embolism: long-term follow-up after treatment with full-dose heparin, streptokinase or embolectomy

The study comprises 74 patients alive 30 days after the start of treatment of pulmonary embolism with heparin (n = 32), streptokinase (n = 22) or embolectomy (n = 20). The cumulative 5-year survival was 100% in the embolectomy group, compared to 75 +/- 7% (SE) in the medically treated patients (p less than 0.05). Cancer caused 78% of the late deaths. At follow-up 0.5-8.7 years after treatment the treatment groups were indistinguishable as regards right-sided heart catheterization data, pulmonary artery rest-obstruction, right ventricular diameter and wall thickness, ventilatory function and ECG changes. The embolectomized patients were in a more favourable NYHA classification level than the medically treated. Chronic pulmonary artery hypertension was found in 75% of patients with greater than or equal to 3 anamnestic recurrent embolic episodes before diagnosis compared to 8% of patients with less than or equal to 2 recurrent episodes (p less than 0.001). Patients with irreversible cardiocirculatory shock before embolectomy all had abnormal pulmonary vascular resistance (greater than 1.5 mmHg/l/min), depressed ventilatory function and more than 25% reduced pulmonary perfusion at follow-up. The major prognostic factors thus were cancer, the number of recurrent episodes and the degree of cardiocirculatory affection in the acute event. Although the embolectomized patients were the most affected initially, they had a good prognosis. This led us to extend our indications for embolectomy to include all patients with central emboli, irrespective of the degree of cardiocirculatory impairment.

Thrombosis of the inferior vena cava, disseminated intravascular coagulation and gangrene of the penis. A case report

Gangrene of the penis following thrombosis of the lower segment of vena cava inferior is reported in a patient who also exhibited clinical and laboratory signs of disseminated intravascular coagulation. Development of the gangrene may have been related to thrombotic occlusion of the right spermatic vein.

A critical review of thromboembolic complications associated with central venous catheters

PURPOSE

Central venous catheters (CVC) are commonly used in critical care. While thrombosis is a well-recognized and frequent complication associated with their use, CVC-related thromboembolic complications, including pulmonary embolism (PE) and right heart thromboembolism (RHTE), occur less frequently and often evade diagnosis. Little information exists to guide clinicians in the diagnosis and management of CVC-related thromboembolic complications.

SOURCE

We critically review and synthesize the literature highlighting the incidence of CVC-related thrombosis. We highlight the risk for developing thromboembolic complications and provide approaches to diagnosing and managing RHTE.

PRINCIPLE FINDINGS

The incidence of CVC-related thrombosis varies depending on patient, site, instrument, and infusate-related factors. Central venous catheters-related thrombosis represents an important source of morbidity and mortality for affected patients. Pulmonary embolism occurs in approximately 15% of patients with CVC-related upper extremity deep venous thrombosis (UEDVT). More frequent use of transesophageal echocardiography, in patients with suspected and confirmed PE, has resulted in increased detection of RHTE. While it is recognized that the occurrence of RHTE, in association with PE, increases mortality, the optimal strategy for their management has not been established in a clinical trial.

CONCLUSION

Central venous catheter-related thrombosis occurs frequently and represents an important source of morbidity and mortality for affected patients. Our review supports that surgery and thrombolysis have both been demonstrated to enhance survival in patients with RHTE and PE. However, important patient, clot, and institutional considerations mandate that treatment for patients with RHTE and PE be individualized.