Pulmonary Embolism — Massive, Submassive, Thrombolysis & Embolectomy

Also known as Pulmonary embolism · PE · Massive PE · Submassive PE · High-risk PE · Intermediate-risk PE · PEITHO trial · MAPPET-3 trial · Systemic thrombolysis · Catheter-directed thrombolysis · Surgical embolectomy · McConnell sign · PESI / sPESI · PERT

Pulmonary embolism is classified by haemodynamic impact. High-risk (massive) PE — shock, hypotension (SBP under 90 mmHg), or arrest — needs immediate systemic thrombolysis (alteplase 100 mg over 2 hours, or an accelerated bolus of 0.6 mg/kg over 15 minutes, maximum 50 mg, in circulatory arrest) or surgical/catheter embolectomy if lysis is contraindicated, with VA-ECMO as a bridge for refractory arrest. Intermediate-high (submassive) PE — normotensive with RV strain on echo and raised biomarkers — is treated with anticoagulation and close monitoring; the PEITHO trial (NEJM 2014) showed systemic lysis prevented haemodynamic decompensation (2.6% vs 5.6%) but increased major bleeding (6.3% vs 1.2%) and stroke (2.4% vs 0.2%) without a mortality benefit, so thrombolysis is reserved for deterioration. Catheter-directed thrombolysis and surgical embolectomy are options when systemic lysis is contraindicated. Anticoagulate with heparin then a DOAC for 3-6 months (provoked) or indefinitely (unprovoked).

high21 referencesUpdated 19 Aug 202615 min readSource-verified · Oct 2026

Checked against its sources on 14 Oct 2026

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Pulmonary embolism is classified by its haemodynamic impact, which drives every management decision. High-risk (massive) PE — cardiac arrest, obstructive shock, or persistent hypotension — needs immediate systemic thrombolysis (alteplase 100 mg over 2 hours, or an accelerated bolus of 0.6 mg/kg over 15 minutes, maximum 50 mg, in circulatory arrest) or surgical/catheter embolectomy if lysis is contraindicated or fails, with VA-ECMO as a bridge for refractory arrest. Anticoagulate with unfractionated heparin (short-acting, reversible) when lysis is given. Intermediate-high (submassive) PE — normotensive with RV strain on echo (the McConnell sign, septal bowing, RV dilatation) and raised biomarkers (troponin, BNP/NT-proBNP) — is treated with anticoagulation and close monitoring, reserving thrombolysis for clinical deterioration. The PEITHO trial (Meyer; tenecteplase vs placebo, 1006 patients) showed systemic lysis reduced death or haemodynamic decompensation at 7 days (2.6% vs 5.6%) but increased major extracranial bleeding (6.3% vs 1.2%) and stroke (2.4% vs 0.2%) without a mortality benefit — so it is not routine. Catheter-directed thrombolysis (ultrasound-assisted, EKOS) delivers a lower lytic dose with less systemic bleeding (ULTIMA, OPTALYSE-PE, SEATTLE II). Low-risk PE (sPESI 0) is anticoagulated and considered for early discharge/home treatment. The diagnosis is CTPA in the stable patient and bedside echocardiography in the unstable. Transition to a DOAC (rivaroxaban, apixaban) for 3-6 months (provoked) or lifelong (unprovoked), and screen survivors for chronic thromboembolic pulmonary hypertension (CTEPH).^[1]^[2]^[3]^[14]

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References21Show

[1]Konstantinides SV, Meyer G, Becattini C, et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS) Eur Respir J, 2019.PMID 31473594
[2]Meyer G, Vicaut E, Danays T, et al. Fibrinolysis for patients with intermediate-risk pulmonary embolism N Engl J Med, 2014.PMID 24716681
[3]Konstantinides S, Geibel A, Heusel G, Heinrich F, et al. Heparin plus alteplase compared with heparin alone in patients with submassive pulmonary embolism N Engl J Med, 2002.PMID 12374874
[4]Chatterjee S, Chakraborty A, Weinberg I, Kadakia M, et al. Thrombolysis for pulmonary embolism and risk of all-cause mortality, major bleeding, and intracranial hemorrhage: a meta-analysis JAMA, 2014.PMID 24938564
[5]Tapson VF, Sterling K, Jones N, Elder M, et al. A Randomized Trial of the Optimum Duration of Acoustic Pulse Thrombolysis Procedure in Acute Intermediate-Risk Pulmonary Embolism: The OPTALYSE PE Trial JACC Cardiovasc Interv, 2018.PMID 30025734
[6]Piazza G, Hohlfelder B, Jaff MR, Ouriel K, et al. A Prospective, Single-Arm, Multicenter Trial of Ultrasound-Facilitated, Catheter-Directed, Low-Dose Fibrinolysis for Acute Massive and Submassive Pulmonary Embolism: The SEATTLE II Study JACC Cardiovasc Interv, 2015.PMID 26315743
[7]McConnell MV, Solomon SD, Rayan ME, Come PC, et al. Regional right ventricular dysfunction detected by echocardiography in acute pulmonary embolism Am J Cardiol, 1996.PMID 8752195
[8]Aujesky D, Obrosky DS, Stone RA, Auble TE, et al. Derivation and validation of a prognostic model for pulmonary embolism Am J Respir Crit Care Med, 2005.PMID 16020800
[9]Jiménez D, Aujesky D, Moores L, Gómez V, et al. Simplification of the pulmonary embolism severity index for prognostication in patients with acute symptomatic pulmonary embolism Arch Intern Med, 2010.PMID 20696966
[10]Büller HR, Prins MH, Lensin AW, et al. Oral rivaroxaban for the treatment of symptomatic pulmonary embolism N Engl J Med, 2012.PMID 22449293
[11]O'Malley TJ, Choi JH, Maynes EJ, Wood CT, et al. Outcomes of extracorporeal life support for the treatment of acute massive pulmonary embolism: A systematic review Resuscitation, 2020.PMID 31790756
[12]Choi JH, O'Malley TJ, Maynes EJ, Weber MP, et al. Surgical Pulmonary Embolectomy Outcomes for Acute Pulmonary Embolism Ann Thorac Surg, 2020.PMID 32151576
[13]Yang J, Madani MM, Mahmud E, Kim NH, et al. Evaluation and Management of Chronic Thromboembolic Pulmonary Hypertension Chest, 2023.PMID 36990148
[14]Bakkum MJ, Schouten VL, Smulders YM, Nossent EJ, et al. Accelerated treatment with rtPA for pulmonary embolism induced circulatory arrest Thromb Res, 2021.PMID 33971387
[15]Kucher N, Boekstegers P, Müller OJ, Kupatt C, et al. Randomized, controlled trial of ultrasound-assisted catheter-directed thrombolysis for acute intermediate-risk pulmonary embolism Circulation, 2014.PMID 24226805
[16]Feltes J, Popova M, Hussein Y, Pierce A, Yamane D. Thrombolytics in Cardiac Arrest from Pulmonary Embolism: A Systematic Review and Meta Analysis J Intensive Care Med, 2024.PMID 38037310
[17]Raschke RA, Reilly BM, Guidry JR, Fontana JR, Srinivas S. The weight-based heparin dosing nomogram compared with a "standard care" nomogram. A randomized controlled trial Ann Intern Med, 1993.PMID 8214998
[18]Büller HR, Davidson BL, Decousus H, Gallus A, et al. Subcutaneous fondaparinux versus intravenous unfractionated heparin in the initial treatment of pulmonary embolism N Engl J Med, 2003.PMID 14585937
[19]Agnelli G, Buller HR, Cohen A, Curto M, et al. Oral apixaban for the treatment of acute venous thromboembolism N Engl J Med, 2013.PMID 23808982
[20]Kearon C, Akl EA, Ornelas J, Blaivas A, et al. Antithrombotic Therapy for VTE Disease: CHEST Guideline and Expert Panel Report Chest, 2016.PMID 26867832
[21]Ebner M, Sentler C, Harjola VP, et al. Outcome of patients with different clinical presentations of high-risk pulmonary embolism. European heart journal. Acute cardiovascular care, 2021.PMID 34125186