By Trushil Shah, MD, MSc
Assistant Professor of Medicine, University of Texas Southwestern, Dallas
Venous thromboembolism (VTE) is common, affecting about 900,000 Americans and leading to 100,000 deaths per year.1 Overall, about 50% of VTEs occur after or during hospitalization and/or surgery. Approximately 150,000 to 250,000 patients require hospitalization for pulmonary embolism (PE). After diagnosis of PE, further management is dictated by risk stratification. Different risk-stratification models are available for use that can include the Pulmonary Embolism Severity Index (PESI) score, the Simplified PESI (sPESI) score, biomarkers (e.g., troponins, brain natriuretic peptide [BNP]/Nt-proBNP), and findings on echocardiography (e.g., presence of right ventricular [RV] strain). Please refer to the August 2017 issue of Critical Care Alert for Samuel Nadler’s excellent discussion for more details.2 Management of PE is addressed after patient classification as high, intermediate, or low risk. This article will review management of pulmonary embolism based on risk stratification, with an emphasis on the role of a Pulmonary Embolism Response Team as well as appropriate follow-up.
Pulmonary Embolism Response Team
Although anticoagulation remains the cornerstone of treatment, some patients may benefit from further treatment with catheter-directed thrombolysis/thrombectomy, systemic thrombolytics, or surgical embolectomy and may even warrant consideration for veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Given the acuity of PE events, associated high mortality, and the need for urgent mobilization of resources, many healthcare systems have moved to a multidisciplinary team approach in the form of a Pulmonary Embolism Response Team (PERT).3
The structure of a PERT varies by institution, but generally it consists of a multidisciplinary team of specialists from pulmonary/critical care, interventional radiology, emergency medicine, cardiothoracic surgery, anesthesiology, cardiology, and hematology.3 Usually there is one point person who gathers information on the patient, and the team convenes in real time over telephone or video conferencing. This expedites formulation of a consensus treatment plan and ensures immediate implementation.3-5 Several studies have shown benefits with the PERT approach as compared to historical controls.6-8 For example, a PERT approach is associated with expedited decision and treatment of intermediate- and high-risk PE and has been shown to improve mortality in high-risk PE patients.6,7,9 Implementation of a PERT also has been associated with decreased length of intensive care unit (ICU) stay and hospitalization.8
ICU Management of Acute Pulmonary Embolism
All patients with PE should receive anticoagulation as first-line treatment unless there is an absolute contraindication. Whenever possible, low molecular weight heparin (LMWH) should be considered first as opposed to unfractionated heparin (UFH) for initial anticoagulation for PE. A Cochrane review of 23 studies comparing LMWH vs. UFH showed that LMWH as an initial therapy is safer and more effective than UFH. LMWH significantly reduced the incidence of thrombotic complications, occurrence of major hemorrhage, and overall mortality at follow-up.10
High-risk PE
Based on various risk stratification models, patients are classified further as high-, intermediate-, or low-risk PE. Low-risk PE can be managed safely as an outpatient or on a general medical floor with anticoagulation alone and does not need PERT consultation.3 High-risk PE is defined as PE with cardiac arrest, signs of shock, and/or persistent hypotension. Shock is associated with significant early risk of death, up to 30% to 50%.11 High-risk PE patients may not be stable enough to confirm the diagnosis with a computed tomography (CT) pulmonary angiogram, and the diagnosis often is made by the presence of RV dysfunction on echocardiogram in the setting of shock.
PERT consultation has been shown to expedite the diagnosis of high-risk PE and the implementation of immediate treatment (e.g., systemic thrombolytics).7 It also can facilitate mechanical circulatory support in the setting of refractory shock/cardiac arrest. Patients with contraindications to thrombolytics should be considered for catheter-directed thrombectomy or surgical embolectomy.
Intermediate-risk PE
Patients with intermediate-risk PE are hemodynamically stable with the presence of RV dysfunction and/or elevated biomarkers (i.e., troponin, BNP). These patients need immediate attention, since they are at risk of decompensation, especially within the first 24 hours of presentation. The presence of RV dysfunction, elevated troponin, and elevated BNP is associated with poor prognosis and increased mortality.12-13 Although systemic thrombolytics are the cornerstone of management in high-risk PE, management of intermediate-risk PE varies according to further prognostication. Intermediate-risk PE is divided further into intermediate-high risk (RV dysfunction and elevated troponin and/or BNP) and intermediate-low risk (RV dysfunction or elevated troponin/BNP).
For intermediate-low risk patients, anticoagulation alone will suffice, and no adjunct treatment modality is needed. For intermediate high-risk patients, reduced-dose thrombolytics or catheter-directed thrombolytics should be considered. It should be noted that the use of both reduced-dose thrombolytics and catheter-directed thrombolytics in intermediate-high risk PE patients mainly expedites improvement in RV function, pulmonary hypertension, and quality of life, but these therapies have not demonstrated any mortality benefit.14-16 In intermediate-high risk patients with a contraindication to thrombolysis, catheter-directed or surgical embolectomy can be considered. Note that further risk stratification of intermediate-risk patients is not perfect, and the patient’s individual presentation should be considered to determine further management. (See Figure 1.) A PERT team provides multidisciplinary opinions in such cases and can help with timely decision-making.
Figure 1: Proposed Treatment Algorithm of Acute Pulmonary Embolism |
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PE: pulmonary embolism; ED: emergency department; ICU: intensive care unit; LMWH: low molecular weight heparin; IVC: inferior vena cava; PERT: Pulmonary Embolism Response Team; SBP: systolic blood pressure; PESI: Pulmonary Embolism Severity Index; RV: right ventricle; CTA: computed tomography angiogram; TTE: transthoracic echocardiogram; BNP: brain natriuretic peptide; tPA: tissue plasminogen activator |
Follow-Up After Acute PE
Intermediate- and high-risk PE patients are at increased risk of clinical worsening during the hospitalization and should be monitored closely for any signs of deterioration.17 PERT should be reconsulted in case of deterioration, and further intervention should be planned as per risk stratification. One of the important components of PERT is assuring appropriate follow-up of PE patients after hospitalization. The INFORM study by Tapson et al showed that the majority of patients with persistent symptoms after PE did not undergo diagnostic testing or further imaging.18
The post-PE follow-up clinic visit should focus on assessing the patient for persistent/recurrent symptoms, the type/dosage/duration of anticoagulation, and medication compliance; evaluating for underlying thrombophilia; screening for cancer as age-appropriate; arranging for temporary inferior vena cava (IVC) filter removal; and diagnosing sequelae of PE (e.g., post-PE syndrome, chronic thromboembolic disease [CTED], and chronic thromboembolic pulmonary hypertension [CTEPH]).3
If a patient has persistent symptoms of dyspnea on exertion, fatigue, lightheadedness, or pedal edema after three months of anticoagulation, further workup with a ventilation perfusion (VQ) scan and echocardiogram should be considered to evaluate for CTED/CTEPH. CTED/CTEPH are treatable with pulmonary thromboendarterectomy (PTE) surgery, with subsequent significant improvement in prognosis.19 Patients with high suspicion or confirmed CTED/CTEPH should be referred to an expert CTEPH center for consideration for PTE and further management.
REFERENCES
- Centers for Disease Control and Prevention. Data and statistics on venous thromboembolism. Updated Feb. 7, 2020. https://www.cdc.gov/ncbddd/dvt/data.html
- Nadler S. Management of pulmonary embolism in the ICU. Crit Care Alert 2017;25:33-37.
- Rivera-Lebron B, McDaniel M, Ahrar K, et al. Diagnosis, treatment and follow up of acute pulmonary embolism: Consensus practice from the PERT consortium. Clin Appl Thromb Hemost 2019;25:1076029619853037.
- Dudzinski DM, Piazza G. Multidisciplinary pulmonary embolism response teams. Circulation 2016;133:98-103.
- Root CW, Dudzinski DM, Zakhary B, et al. Multidisciplinary approach to the management of pulmonary embolism patients: The pulmonary embolism response team (PERT). J Multidiscip Healthc 2018;11:187-195.
- Wright C, Elbadawi A, Chen YL, et al. The impact of a pulmonary embolism response team on the efficiency of patient care in the emergency department. J Thromb Thrombolysis 2019;48:331-335.
- Wright C, Goldenberg I, Schleede S, et al. Effect of a multidisciplinary pulmonary embolism response team on patient mortality. Am J Cardiol 2021;161:102-107.
- Xenos ES, Davis GA, He Q, et al. The implementation of a pulmonary embolism response team in the management of intermediate- or high-risk pulmonary embolism. J Vasc Surg Venous Lymphat Disord 2019;7:493-500.
- Rosovsky R, Chang Y, Rosenfield K, et al. Changes in treatment and outcomes after creation of a pulmonary embolism response team (PERT), a 10-year analysis. J Thromb Thrombolysis 2019;47:31-40.
- Erkens PM, Prins MH. Fixed dose subcutaneous low molecular weight heparins versus adjusted dose unfractionated heparin for venous thromboembolism. Cochrane Database Syst Rev 2010;9:CD001100.
- Ebner M, Sentler C, Harjola VP, et al. Outcome of patients with different clinical presentations of high-risk pulmonary embolism. Eur Heart J Acute Cardiovasc Care 2021;10:787-796.
- ten Wolde M, Söhne M, Quak E, et al. Prognostic value of echocardiographically assessed right ventricular dysfunction in patients with pulmonary embolism. Arch Intern Med 2004;164:1685-1689.
- Klok FA, Mos IC, Huisman MV. Brain-type natriuretic peptide levels in the prediction of adverse outcome in patients with pulmonary embolism: A systematic review and meta-analysis. Am J Respir Crit Care Med 2008;178:425-430.
- Sharifi M, Bay C, Skrocki L, et al. Moderate pulmonary embolism treated with thrombolysis (from the “MOPETT” Trial). Am J Cardiol 2013;111:273-277.
- Piazza G, Sterling KM, Tapson VF, et al. One-year echocardiographic, functional, and quality of life outcomes after ultrasound-facilitated catheter-based fibrinolysis for pulmonary embolism. Circ Cardiovasc Interv 2020;13:e009012.
- Kucher N, Boekstegers P, Müller, et al. Randomized, controlled trial of ultrasound-assisted catheter-directed thrombolysis for acute intermediate-risk pulmonary embolism. Circulation 2014;129:479-486.
- Kabrhel C, Okechukwu I, Hariharan P, et al. Factors associated with clinical deterioration shortly after PE. Thorax 2014;69:835-842.
- Tapson VF, Platt DM, Xia F, et al. Monitoring for pulmonary hypertension following pulmonary embolism: The INFORM study. Am J Med 2016;129:978-985 e2.
- Delcroix M, Lang I, Pepke-Zaba J, et al. Long-term outcome of patients with chronic thromboembolic pulmonary hypertension: Results from an international prospective registry. Circulation 2016;133:859-871.
This article will review management of pulmonary embolism based on risk stratification, with an emphasis on the role of a Pulmonary Embolism Response Team as well as appropriate follow-up.
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