Thrombolysis in hemodynamically stable patients with acute pulmonary embolism: A meta-analysis

Fibrinolytic Agents in Thromboembolic Diseases: Historical Perspectives and Approved Indications

Fibrinolytic agents catalyze the conversion of the inactive proenzyme plasminogen into the active protease plasmin, degrading fibrin within the thrombus and recanalizing occluded vessels. The history of these medications dates to the discovery of the first fibrinolytic compound, streptokinase, from bacterial cultures in 1933. Over time, researchers identified two other plasminogen activators in human samples, namely urokinase and tissue plasminogen activator (tPA). Subsequently, tPA was cloned using recombinant DNA methods to produce alteplase. Several additional derivatives of tPA, such as tenecteplase and reteplase, were developed to extend the plasma half-life of tPA. Over the past decades, fibrinolytic medications have been widely used to manage patients with venous and arterial thromboembolic events. Currently, alteplase is approved by the U.S. Food and Drug Administration (FDA) for use in patients with pulmonary embolism with hemodynamic compromise, ST-segment elevation myocardial infarction (STEMI), acute ischemic stroke, and central venous access device occlusion. Reteplase and tenecteplase have also received FDA approval for treating patients with STEMI. This review provides an overview of the historical background related to fibrinolytic agents and briefly summarizes their approved indications across various thromboembolic diseases.

Reduced-Dose Thrombolysis in Acute Pulmonary Embolism A Systematic Review

Pulmonary embolism (PE) is the third-leading cause of cardiovascular mortality and the second-leading cause of death in cancer patients. The clinical efficacy of thrombolysis for acute PE has been proven, yet the therapeutic window seems narrow, and the optimal dosing for pharmaceutical reperfusion therapy has not been established. Higher doses of systemic thrombolysis inevitably associated with an incremental increase in major bleeding risk. To date, there is no high-quality evidence regarding dosing and infusion rates of thrombolytic agents to treat acute PE. Most clinical trials have focused on thrombolysis compared with anticoagulation alone, but dose-finding studies are lacking. Evidence is now emerging that lower-dose thrombolytic administered through a peripheral vein is efficacious in accelerating thrombolysis in the central pulmonary artery and preventing acute right heart failure, with reduced risk for major bleeding. The present review will systematically summarize the current evidence of low-dose thrombolysis in acute PE.

Ultra-Low-Dose Systemic Tissue Plasminogen Activator in High-Risk Submassive Pulmonary Embolism

Risk stratification of pulmonary embolism (PE) is vital for clinical management. While low-risk and high-risk PE management are clearly defined in many societal guidelines, the management of moderate-risk, also called submassive, PE remains unsettled. There is a subgroup of patients with submassive PE that progress to the severe category despite receiving systemic anticoagulation. The role of thrombolysis in the management of submassive PE remains to be established. We share our experience with ultra-low-dose (25-mg) systemic tissue plasminogen activator in a series of 4 patients with high-risk submassive PE.

Injection of Recombinant Tissue Plasminogen Activator into Extracorporeal Membrane Oxygenators Postpones Oxygenator Exchange in COVID-19

Coronavirus disease 2019 (COVID-19) has drastically increased the number of patients requiring extracorporeal life support. We investigate the efficacy and safety of low-dose recombinant tissue-type plasminogen activator (rtPA) injection into exhausted oxygenators to delay exchange in critically ill COVID-19 patients on veno-venous extracorporeal membrane oxygenation (V-V ECMO). Small doses of rtPA were injected directly into the draining section of a V-V ECMO circuit. We compared transmembrane pressure gradient, pump head efficiency, membrane arterial partial oxygen pressure, and membrane arterial partial carbon dioxide pressure before and after the procedure. Bleeding was compared with a matched control group of 20 COVID-19 patients on V-V ECMO receiving standard anticoagulation. Four patients received 16 oxygenator instillations with rtPA at 5, 10, or 20 mg per dose. Administration of rtPA significantly reduced transmembrane pressure gradient (Δpm = 54.8 ± 18.1 mmHg before vs. 38.3 ± 13.3 mmHg after, p < 0.001) in a dose-dependent manner (Pearson's R -0.63, p = 0.023), allowing to delay oxygenator exchange, thus reducing the overall number of consumed oxygenators. rtPA increased blood flow efficiency η (1.20 ± 0.28 ml/revolution before vs. 1.24 ± 0.27 ml/r, p = 0.002). Lysis did not affect membrane blood gases or systemic coagulation. Minor bleeding occurred in 2 of 4 patients (50%) receiving oxygenator lysis as well as 19 of 20 control patients (95%). Lysis of ECMO oxygenators effectively delays oxygenator exchange, if exchange is indicated by an increase in transmembrane pressure gradient. Application of lysis did not result in higher bleeding incidences compared with anticoagulated patients on V-V ECMO for COVID-19.

Modulation of soluble guanylate cyclase ameliorates pulmonary hypertension in a rat model of chronic thromboembolic pulmonary hypertension by stimulating angiogenesis

Acute pulmonary embolism (PE) does not always resolve after treatment and can progress to chronic thromboembolic disease (CTED) or the more severe chronic thromboembolic pulmonary hypertension (CTEPH). The mechanisms surrounding the likelihood of PE resolution or progress to CTED/CTEPH remain largely unknown. We have developed a rat model of CTEPH that closely resembles the human disease in terms of hemodynamics and cardiac manifestations. Embolization of rats with polystyrene microspheres followed by suppression of angiogenesis with the inhibitor of vascular endothelial growth factor receptor 2 (VEGF-R2) SU5416 results in transient, acute pulmonary hypertension that progresses into chronic PE with PH with sustained right ventricular systolic pressures exceeding 70 mmHg (chronic pulmonary embolism [CPE] model). This model is similar to the widely utilized hypoxia/SU5416 model with the exception that the "first hit" is PE. Rats with CPE have impaired right heart function characterized by reduced VO2 Max, reduced cardiac output, and increased Fulton index. None of these metrics are adversely affected by PE alone. Contrast-mediated CT imaging of lungs from rats with PE minus SU5416 show large increases in pulmonary vascular volume, presumably due to an angiogenic response to acute PE/PH. Co-treatment with SU5416 suppresses angiogenesis and produces the CTEPH-like phenotype. We report here that treatment of CPE rats with agonists for soluble guanylate cyclase, a source of cGMP which is in turn a signal for angiogenesis, markedly increases angiogenesis in lungs, and ameliorates the cardiac deficiencies in the CPE model. These results have implications for future development of therapies for human CTEPH.

Catheter-Directed Therapies in Patients with Pulmonary Embolism: Predictive Factors of In-Hospital Mortality and Long-Term Follow-Up

(1) Background: Catheter-directed therapies (CDT) may be considered for selected patients with pulmonary embolism (PE); (2) Methods: Retrospective observational study including all consecutive patients with acute PE undergoing CDT (mechanical or pharmacomechanical) from January 2010 through December 2020. The aim was to evaluate in-hospital and long-term mortality and its predictive factors; (3) Results: We included 63 patients, 43 (68.3%) with high-risk PE. All patients underwent mechanical CDT and, additionally, 27 (43%) underwent catheter-directed thrombolysis. Twelve (19%) patients received failed systemic thrombolysis (ST) prior to CDT, and an inferior vena cava (IVC) filter was inserted in 28 (44.5%) patients. In-hospital PE-related and all-cause mortality rates were 31.7%; 95% CI 20.6-44.7% and 42.9%; 95% CI 30.5-56%, respectively. In multivariate analysis, age > 70 years and previous ST were strongly associated with PE-related and all-cause mortality, while IVC filter insertion during the CDT was associated with lower mortality rates. After a median follow-up of 40 (12-60) months, 11 more patients died (mortality rate of 60.3%; 95% CI 47.2-72.4%). Long-term survival was significantly higher in patients who received an IVC filter; (4) Conclusions: Age > 70 years and failure of previous ST were associated with mortality in acute PE patients treated with CDT. In-hospital and long-term mortality were lower in patients who received IVC filter insertion.

Reduced-Dose Intravenous Thrombolysis for Acute Intermediate-High-risk Pulmonary Embolism: Rationale and Design of the Pulmonary Embolism International THrOmbolysis (PEITHO)-3 trial

Intermediate–high-risk pulmonary embolism (PE) is characterized by right ventricular (RV) dysfunction and elevated circulating cardiac troponin levels despite apparent hemodynamic stability at presentation. In these patients, full-dose systemic thrombolysis reduced the risk of hemodynamic decompensation or death but increased the risk of life-threatening bleeding. Reduced-dose thrombolysis may be capable of improving safety while maintaining reperfusion efficacy. The Pulmonary Embolism International THrOmbolysis (PEITHO)-3 study (ClinicalTrials.gov Identifier: NCT04430569) is a randomized, placebo-controlled, double-blind, multicenter, multinational trial with long-term follow-up. We will compare the efficacy and safety of a reduced-dose alteplase regimen with standard heparin anticoagulation. Patients with intermediate–high-risk PE will also fulfill at least one clinical criterion of severity: systolic blood pressure ≤110 mm Hg, respiratory rate >20 breaths/min, or history of heart failure. The primary efficacy outcome is the composite of all-cause death, hemodynamic decompensation, or PE recurrence within 30 days of randomization. Key secondary outcomes, to be included in hierarchical analysis, are fatal or GUSTO severe or life-threatening bleeding; net clinical benefit (primary efficacy outcome plus severe or life-threatening bleeding); and all-cause death, all within 30 days. All outcomes will be adjudicated by an independent committee. Further outcomes include PE-related death, hemodynamic decompensation, or stroke within 30 days; dyspnea, functional limitation, or RV dysfunction at 6 months and 2 years; and utilization of health care resources within 30 days and 2 years. The study is planned to enroll 650 patients. The results are expected to have a major impact on risk-adjusted treatment of acute PE and inform guideline recommendations.

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.

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.

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.

Submassive Pulmonary Embolism

Pulmonary embolism (PE) presents a spectrum of hemodynamic consequences, ranging from being asymptomatic to a life-threatening medical emergency. Management of submassive and massive PE often involves clinicians from multiple specialties, which can potentially delay the development of a unified treatment plan. In addition, patients with submassive PE can deteriorate after their presentation and require escalation of care. Underlying comorbidities such as chronic obstructive pulmonary disease, cancer, congestive heart failure, and interstitial lung disease can impact the patient's hemodynamic ability to tolerate submassive PE. In this review, we address the definitions, risk stratification (clinical, laboratory, and imaging), management approaches, and long-term outcomes of submassive PE. We also discuss the role of the PE response team in management of patients with PE.

Pearls and Myths in the Evaluation of Patients with Suspected Acute Pulmonary Embolism

Significant improvement has been achieved in diagnostic accuracy, validation of probability scores, and standardized treatment algorithms for patients with suspected acute pulmonary embolism. These developments have provided the tools for a safe and cost-effective management for most of these patients. In our experience, however, the presence of medical myths and ongoing controversies seem to hinder the implementation of these tools in everyday clinical practice. This review provides a selection of such dilemmas and controversies and discusses the published evidence beyond them. By doing so, we try to overcome these dilemmas and suggest pragmatic approaches guided by the available evidence and current guidelines.

Prise en charge de l'embolie pulmonaire grave en réanimation

L'embolie pulmonaire (EP) grave, définie par la présence d’un état de choc, est à l'origine d'une mortalité importante. L'objectif de cette mise au point est de synthétiser les dernières avancées et recommandations concernant la prise en charge des formes graves d'EP. La stratification du risque individuel de mortalité précoce permet d'apporter une stratégie diagnostique et thérapeutique optimisée pour chaque patient. Le traitement symptomatique consiste essentiellement en la prise en charge de l'état de choc. L'anticoagulation curative par héparine non fractionnée est réservée aux patients hémodynamiquement instables. Chez ces patients à haut risque, la thrombolyse systémique diminue la mortalité et le risque de récidive d'EP. Chez les patients à risque intermédiaire élevé, la thrombolyse systémique à dose standard diminue le risque de choc secondaire mais sans impact sur la mortalité globale. La thrombolyse est donc réservée aux patients à risque intermédiaire élevé présentant secondairement un état de choc. L'embolectomie chirurgicale reste indiquée en cas de contre-indication absolue à la thrombolyse ou en cas d'échec de celle-ci. Le positionnement dans l'algorithme thérapeutique de l'assistance extracorporelle et des techniques percutanées de revascularisation reste à définir. Leurs indications doivent donc être discutées dans des centres experts après une concertation multidisciplinaire incluant pneumologues, cardiologues, réanimateurs, radiologues interventionnels et chirurgiens cardiaques.

Comparison of acute and convalescent biomarkers of inflammation in patients with acute pulmonary embolism treated with systemic fibrinolysis vs. placebo

: Previous studies have associated biomarkers indicative of acute inflammation with pulmonary embolism, which may amplify coagulation, inhibit fibrinolysis and increase risk of venous thromboembolism (VTE) recurrence. The aim of this study was to measure inflammatory and hemostatic biomarkers in acute submassive pulmonary embolism at diagnosis and 3-month follow-up and to test the impact of treatment with fibrinolysis. Secondary analysis of a multicenter, double-blinded, randomized controlled trial including patients with submassive pulmonary embolism. Blood samples were obtained within 24 h of diagnosis and prior to bolus-dose tenecteplase (TNK) or placebo; all patients received standard anticoagulation and blood was redrawn 3 months later. Plasma concentrations of inflammatory [Interleukin 6 (IL-6), C-reactive protein (CRP), myeloperoxidase (MPO)] and hemostatic [plasminogen activator inhibitor-1 (PAI-1), fibrinogen, thrombin-activatable fibrinolysis inhibitor and D-dimer] biomarkers were quantified. The median values of the biomarkers of inflammation (IL-6, CRP, MPO) were all significantly decreased at 3-month follow-up, ranging from a 60 to 91% reduction over this time period. Concentrations of PAI-1 and fibrinogen did not change significantly. D-dimer concentration at 3-month follow-up was lower in patients treated with fibrinolysis vs. placebo and appeared to have a trend toward significance (placebo 310 vs. TNK 220 ng/ml, P = 0.051). Acute pulmonary embolism causes marked but transient inflammation, as demonstrated by the significant elevation in the inflammatory biomarkers at diagnosis, followed by their reduction in more than 80% of patients at 3-month follow-up.

Local low-dose urokinase thrombolysis for the management of haemodynamically stable pulmonary embolism with right ventricular dysfunction

AIMS

The aim of this study was to evaluate the effectiveness of local low-dose urokinase thrombolysis (LLDUT) in haemodynamically stable pulmonary embolism with right ventricular dysfunction (RVD).

METHODS AND RESULTS

This was a prospective study. LLDUT with a 200,000 IU bolus followed by a 100,000 IU/hr infusion was given. Treatment duration was determined through radiological control performed 48-72 hrs into treatment. A follow-up echocardiogram was performed within seven days after LLDUT completion. Evolution of thrombus burden, pulmonary artery pressures (PAP) and RVD were studied, and haemorrhagic complications and mortality were recorded. Eighty-seven patients were included (62.5±16.5 years). In 67 patients (77%), the baseline echocardiogram showed mild-to-severe RVD, a dilated right ventricle (diameter: 44.4±6.2 mm) and a decreased tricuspid annular plane systolic excursion (14 mm [12-17]). Seventy-six patients (87.4%) experienced radiological improvement. Initially high PAP (mmHg) decreased after LLDUT: systolic 52.4 vs. 35.2 (17.2 [95% CI: 14.5-19.9]; p<0.0001), mean 34.2 vs. 23.5 (10.7 [95% CI: 9.0-12.5]; p<0.0001) and diastolic 23.9 vs. 16.0 (7.9 [95% CI: 6.1-9.7]; p<0.0001). Follow-up echocardiography showed overall improvement of RVD. No life-threatening haemorrhagic complications were reported. Six-month survival was 96.5%.

CONCLUSIONS

LLDUT rapidly decreased thrombus burden and PAP, improving right ventricular function, and was not associated with any life-threatening complications or pulmonary embolism (PE)- or treatment-related mortality.

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.

Surgical pulmonary embolectomy and catheter-directed thrombolysis for treatment of submassive pulmonary embolism

BACKGROUND

Acute pulmonary embolism (PE) with preserved hemodynamics but right ventricular dysfunction, classified as submassive PE, carries a high risk of mortality. We report the results for patients who did not qualify for medical therapy and required treatment of submassive PE with surgical pulmonary embolectomy and catheter-directed thrombolysis (CDT).

METHODS

Between October 1999 and May 2015, 133 submassive PE patients underwent treatment with pulmonary embolectomy (71) and CDT (62). A multidisciplinary PE response team helped to determine the most appropriate treatment strategy on a case-by-case basis. The EkoSonic ultrasound-facilitated thrombolysis system (EKOS) was used for CDT, which was introduced in 2010.

RESULTS

The mean age of submassive PE patients was 57.3 years, which included 36.8% females. PE risk factors included previous deep venous thrombosis (46.6%), immobility (36.1%), recent surgery (30.8%), and cancer (22.6%), P < 0.05. The most common indication for advanced treatment was right ventricular strain (42.9%), P = 0.03. The frequency of surgical pulmonary embolectomy remained stable even after incorporating the EKOS procedure into our treatment algorithm, with statistically similar operative mortality. Bleeding was observed in six CDT patients and one pulmonary embolectomy patient (P < 0.05). Follow-up echocardiography was available for 61% of the overall cohort, of whom 76.5% had no residual moderate or severe right ventricular dysfunction.

CONCLUSIONS

Pulmonary embolectomy and CDT are important contemporary advanced treatment options for selected high-risk patients with submassive PE, who do not qualify for medical therapy.

Venous Thromboembolism and Pulmonary Embolism Response Teams: An Overview

Venous thromboembolism is a common disease with a wide array of signs and symptoms. It has been cited as the third leading cause of cardiovascular death, and if left untreated, it leads to death in 1 in 4 patients. Sophisticated diagnostic tools have allowed physician to become more accurate in diagnosing pulmonary embolism and deep vein thrombosis. The advent of new oral anticoagulants, the emergence of pulmonary embolism response teams, and protocols demonstrate recent achievements in the management of venous thromboembolism. The focus of this article is to discuss the treatment of venous thromboembolism.

Systemic Thrombolysis for Pulmonary Embolism: Who and How

Anticoagulation has been shown to improve mortality in acute pulmonary embolism (PE). Initiation of anticoagulation should be considered when PE is strongly suspected and the bleeding risk is perceived to be low, even if acute PE has not yet been proven. Low-risk patients with acute PE are simply continued on anticoagulation. Severely ill patients with high-risk (massive) PE require aggressive therapy, and if the bleeding risk is acceptable, systemic thrombolysis should be considered. However, despite clear evidence that parenteral thrombolytic therapy leads to more rapid clot resolution than anticoagulation alone, the risk of major bleeding including intracranial bleeding is significantly higher when systemic thrombolytic therapy is administered. It has been demonstrated that right ventricular dysfunction, as well as abnormal biomarkers (troponin and brain natriuretic peptide) are associated with increased mortality in acute PE. In spite of this, intermediate-risk (submassive) PE comprises a fairly broad clinical spectrum. For several decades, clinicians and clinical trialists have worked toward a more aggressive, yet safe solution for patients with intermediate-risk PE. Standard-dose thrombolysis, low-dose systemic thrombolysis, and catheter-based therapy which includes a number of devices and techniques, with or without low-dose thrombolytic therapy, have offered potential solutions and this area has continued to evolve. On the basis of heterogeneity within the category of intermediate-risk as well as within the high-risk group of patients, we will focus on the use of systemic thrombolysis in carefully selected high- and intermediate-risk patients. In certain circumstances when the need for aggressive therapy is urgent and the bleeding risk is acceptable, this is an appropriate approach, and often the best one.

The value of electrocardiography in prognosticating clinical deterioration and mortality in acute pulmonary embolism: A systematic review and meta-analysis

The role of electrocardiography (ECG) in prognosticating pulmonary embolism (PE) is increasingly recognized. ECG is quickly interpretable, noninvasive, inexpensive, and available in remote areas. We hypothesized that ECG can provide useful information about PE prognostication. We searched MEDLINE, EMBASE, Google Scholar, Web of Science, abstracts, conference proceedings, and reference lists through February 2017. Eligible studies used ECG to prognosticate for the main outcomes of death and clinical deterioration or escalation of therapy. Two authors independently selected studies; disagreement was resolved by consensus. Ad hoc piloted forms were used to extract data and assess risk of bias. We used a random-effects model to pool relevant data in meta-analysis with odds ratios (ORs) and 95% confidence intervals (CIs); all other data were synthesized qualitatively. Statistical heterogeneity was assessed using the I ² value. We included 39 studies (9198 patients) in the systematic review. There was agreement in study selection (κ: 0.91, 95% CI: 0.86-0.96). Most studies were retrospective; some did not appropriately control for confounders. ECG signs that were good predictors of a negative outcome included S1Q3T3 (OR: 3.38, 95% CI: 2.46-4.66, P < 0.001), complete right bundle branch block (OR: 3.90, 95% CI: 2.46-6.20, P < 0.001), T-wave inversion (OR: 1.62, 95% CI: 1.19-2.21, P = 0.002), right axis deviation (OR: 3.24, 95% CI: 1.86-5.64, P < 0.001), and atrial fibrillation (OR: 1.96, 95% CI: 1.45-2.67, P < 0.001) for in-hospital mortality. Several ischemic patterns also were significantly predictive. Our conclusion is that ECG is potentially valuable in prognostication of acute PE.

Hemostatic Markers and Long-Term Risk of Intracerebral Hemorrhage in Postmenopausal Women

BACKGROUND

Known risk factors for intracerebral hemorrhage (ICH) include age, hypertension, smoking, alcohol intake, and anticoagulant use. Some previous reports have indicated that hemostatic factors measured many years before the onset of ICH might predict the later occurrence of ICH. The objective of this analysis was to test whether selected hemostatic factors measured years before the onset of ICH could identify patients at higher risk for future ICH.

METHODS

We performed a nested case-control study within the Women's Health Initiative (WHI) cohort. Postmenopausal women aged 50-79 years (mean 68) at baseline (1993-1998) were enrolled at 40 Clinical Centers in the United States and followed for adjudicated ICH for a mean of 11.4 years. ICH cases (N = 75) and controls (N = 75) were matched on age, ethnicity, blood pressure, anticoagulant use, and treated hypertension. Stored blood samples from the baseline WHI examination were tested for von Willebrand factor (vWF), a disintegrin-like and metalloprotease domain with thrombospondin type-1 motif, number 13 (ADAMTS13), tissue plasminogen activator (t-PA), and urokinase plasminogen activator (u-PA). Platelet count, white blood cell count, and hemoglobin concentration were also measured.

RESULTS

Mean baseline levels of vWF (1.03 and .95 U/mL), ADAMTS13 (1.0 and 1.1 µg/mL), vWF : ADAMTS13 ratio (.99 and .92), t-PA (14.75 and 14.80 IU/mL), and u-PA (.09 and .10 IU/mL) were not significantly different by case-control status. Significant differences were also not identified for platelet count, hemoglobin, white blood count, or reported alcohol use.

CONCLUSION

None of the 4 baseline hemostatic factors nor the platelet count was predictive of future ICH risk in this long-term study of older postmenopausal women.

Variable Resistance to Plasminogen Activator Initiated Fibrinolysis for Intermediate-Risk Pulmonary Embolism

Background

We examine the clinical significance and biomarkers of tissue plasminogen activator (tPA)-catalyzed clot lysis time (CLT) in patients with intermediate-risk pulmonary embolism (PE).

Methods

Platelet-poor, citrated plasma was obtained from patients with PE. Healthy age- and sex-matched patients served as disease-negative controls. Fibrinogen, α₂-antiplasmin, plasminogen, thrombin activatable fibrinolysis inhibitor (TAFI), plasminogen activator Inhibitor 1 (PAI-1), thrombin time and D-dimer were quantified. Clotting was induced using CaCl₂, tissue factor, and phospholipid. Lysis was induced using 60 ng/mL tPA. Time to 50% clot lysis (CLT) was assessed by both thromboelastography (TEG) and turbidimetry (A405).

Results

Compared with disease-negative controls, patients with PE exhibited significantly longer mean CLT on TEG (+2,580 seconds, 95% CI 1,380 to 3,720 sec). Patients with PE and a short CLT who were treated with tenecteplase had increased risk of bleeding, whereas those with long CLT had significantly worse exercise tolerance and psychometric testing for quality of life at 3 months. A multivariate stepwise removal regression model selected PAI-1 and TAFI as predictive biomarkers of CLT.

Conclusion

The CLT from TEG predicted increased risk of bleeding and clinical failure with tenecteplase treatment for intermediate-risk PE. Plasmatic PAI-1 and TAFI were independent predictors of CLT.

Antithrombotic Therapy for VTE Disease: CHEST Guideline and Expert Panel Report

BACKGROUND

We update recommendations on 12 topics that were in the 9th edition of these guidelines, and address 3 new topics.

METHODS

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

RESULTS

For VTE and no cancer, as long-term anticoagulant therapy, we suggest dabigatran (Grade 2B), rivaroxaban (Grade 2B), apixaban (Grade 2B), or edoxaban (Grade 2B) over vitamin K antagonist (VKA) therapy, and suggest VKA therapy over low-molecular-weight heparin (LMWH; Grade 2C). For VTE and cancer, we suggest LMWH over VKA (Grade 2B), dabigatran (Grade 2C), rivaroxaban (Grade 2C), apixaban (Grade 2C), or edoxaban (Grade 2C). We have not changed recommendations for who should stop anticoagulation at 3 months or receive extended therapy. For VTE treated with anticoagulants, we recommend against an inferior vena cava filter (Grade 1B). For DVT, we suggest not using compression stockings routinely to prevent PTS (Grade 2B). For subsegmental pulmonary embolism and no proximal DVT, we suggest clinical surveillance over anticoagulation with a low risk of recurrent VTE (Grade 2C), and anticoagulation over clinical surveillance with a high risk (Grade 2C). We suggest thrombolytic therapy for pulmonary embolism with hypotension (Grade 2B), and systemic therapy over catheter-directed thrombolysis (Grade 2C). For recurrent VTE on a non-LMWH anticoagulant, we suggest LMWH (Grade 2C); for recurrent VTE on LMWH, we suggest increasing the LMWH dose (Grade 2C).

CONCLUSIONS

Of 54 recommendations included in the 30 statements, 20 were strong and none was based on high-quality evidence, highlighting the need for further research.

Recent developments in the diagnosis and treatment of pulmonary embolism

Due to the nonspecific symptoms of the condition, a diagnosis of acute pulmonary embolism (PE) is frequently considered. However, PE will only be confirmed in 10-20% of patients. Because the imaging test of choice, computed tomography pulmonary angiography (CTPA), is costly and associated with radiation exposure and other complications, a validated diagnostic algorithm consisting of a clinical decision rule and D-dimer test should be used to safely exclude PE in 20-30% of patients without the need for CTPA. Recently, the age-adjusted D-dimer threshold has been validated, and this has increased the proportion of patients at older age in whom PE can be excluded without CTPA. Initial therapeutic management of PE depends on the risk of short-term PE-related mortality. Haemodynamically unstable patients should be closely monitored and receive thrombolytic therapy unless contraindicated because of an unacceptably high bleeding risk, whereas patients with low-risk PE may be safely discharged early from hospital or receive only outpatient treatment. The PESI score and Hestia decision rule are available to select patients in whom early discharge or outpatient treatment will be safe, although the safety of these strategies should be confirmed in additional studies. Standard PE therapy consists of low molecular weight heparin (LMWH) followed by vitamin K antagonists (VKAs). Recently, several nonvitamin K-dependent oral anticoagulants have been shown to be as effective as LMWH/VKAs, and maybe safer. Determining the optimal duration of treatment for a first unprovoked PE remains a challenge, although clinical prediction rules for estimating the risk of recurrence of venous thromboembolism and anticoagulation-associated haemorrhage are under investigation. Using these prediction rules may lead to both more standardized and more individualized long-term treatment of PE.

Findings From 12-lead Electrocardiography That Predict Circulatory Shock From Pulmonary Embolism: Systematic Review and Meta-analysis

OBJECTIVES

Treatment guidelines for acute pulmonary embolism (PE) recommend risk stratifying patients to assess PE severity, as those at higher risk should be considered for therapy in addition to standard anticoagulation to prevent right ventricular (RV) failure, which can cause hemodynamic collapse. The hypothesis was that 12-lead electrocardiography (ECG) can aid in this determination. The objective of this study was to measure the prognostic value of specific ECG findings (the Daniel score, which includes heart rate > 100 beats/min, presence of the S1Q3T3 pattern, incomplete and complete right bundle branch block [RBBB], and T-wave inversion in leads V1-V4, plus ST elevation in lead aVR and atrial fibrillation suggestive of RV strain from acute pulmonary hypertension), in patients with acute PE.

METHODS

Studies were identified by a structured search of MEDLINE, PubMed, EMBASE, the Cochrane library, Google Scholar, Scopus, and bibliographies in October 2014. Case reports, non-English papers, and those that lacked either patient outcomes or ECG findings were excluded. Papers with evidence of a predefined reference standard for PE and the results of 12-lead ECG, stratified by outcome (hemodynamic collapse, defined as circulatory shock requiring vasopressors or mechanical ventilation, or in hospital or death within 30 days) were included. Papers were assessed for selection and publication bias. The authors also assessed heterogeneity (I(2) ) and calculated the odds ratios (OR) for each ECG sign from the random effects model if I(2) > 24% and fixed effects if I(2) < 25%. Funnel plots were used to examine for publication bias.

RESULTS

Forty-five full-length studies of 8,209 patients were analyzed. The most frequent ECG signs found in patients with acute PE were tachycardia (38%), T-wave inversion in lead V1 (38%), and ST elevation in lead aVR (36%). Ten studies with 3,007 patients were included for full analysis. Six ECG findings (heart rate > 100 beats/min, S1Q3T3, complete RBBB, inverted T waves in V1-V4, ST elevation in aVR, and atrial fibrillation) had likelihood and ORs with lower-limit 95% confidence intervals above unity, suggesting them to be significant predictors of hemodynamic collapse and 30-day mortality. OR data showed no evidence of publication bias, but the proportions of patients with hemodynamic collapse or death and S1Q3T3 and RBBB tended to be higher in smaller studies. Patients who were outcome-negative had a significantly lower mean ± SD Daniel score (2.6 ± 1.5) than patients with hemodynamic collapse (5.9 ± 3.9; p = 0.039, ANOVA with Dunnett's post hoc), but not patients with all-cause 30-day mortality (4.9 ± 3.3; p = 0.12).

CONCLUSIONS

This systematic review and meta-analysis revealed 10 studies, including 3,007 patients with acute PE, that demonstrate that six findings of RV strain on 12-lead ECG (heart rate > 100 beats/min, S1Q3T3, complete RBBB, inverted T waves in V1-V4, ST elevation in aVR, and atrial fibrillation) are associated with increased risk of circulatory shock and death.