What is the recommended treatment for a hemodynamically unstable patient with acute pulmonary embolism (PE) and signs of right heart strain, considering thrombolysis with alteplase (tissue plasminogen activator, tPA)?

Thrombolysis for Hemodynamically Unstable Pulmonary Embolism

Administer systemic thrombolysis with alteplase immediately to hemodynamically unstable patients with acute PE and right heart strain, as this is a life-saving intervention that should not be delayed. 1

Immediate Management Algorithm

Step 1: Identify Hemodynamic Instability

Massive PE is highly likely when the following are present together: 1

• Collapse or sustained hypotension (systolic BP <90 mmHg for ≥15 minutes)
• Unexplained hypoxia
• Engorged neck veins
• Right ventricular gallop (often present)

Step 2: Initiate Treatment Based on Clinical State

For Cardiac Arrest: 1

• Begin CPR immediately
• Administer 50 mg alteplase IV bolus during resuscitation
• Reassess at 30 minutes

For Deteriorating Patients (shock developing): 1

• Contact senior consultant immediately
• Administer 50 mg alteplase IV bolus
• Do not delay for imaging confirmation if clinical presentation is compelling

For Stable Patients with Confirmed Massive PE: 1

• Administer 100 mg alteplase IV over 90 minutes (accelerated MI regimen)
• Start with 80 units/kg unfractionated heparin IV bolus
• Arrange urgent echocardiography or CTPA

Step 3: Post-Thrombolysis Management

• Begin weight-adjusted unfractionated heparin infusion 3 hours after thrombolysis completion 1
• Monitor closely for bleeding complications and hemodynamic response

Critical Decision Points

When Bleeding Risk is High

Contraindications to thrombolysis should be ignored in life-threatening PE 1. The mortality benefit in hemodynamically unstable PE outweighs bleeding risks, even when traditional contraindications exist. 1, 2

Alternative Interventions if Thrombolysis Fails or is Contraindicated

If appropriate expertise and resources are available, consider catheter-assisted thrombus removal or surgical embolectomy for patients with: 1

• High bleeding risk that cannot be ignored
• Failed systemic thrombolysis
• Shock likely to cause death within hours before thrombolysis can take effect

Prefer systemic thrombolysis via peripheral vein over catheter-directed thrombolysis when both options are available, as systemic therapy is more readily accessible and equally effective. 1

Common Pitfalls to Avoid

Do Not Delay Treatment for Imaging

In patients with clinical features of massive PE (hypotension, hypoxia, engorged neck veins, RV gallop), do not delay thrombolysis while awaiting confirmatory imaging if the patient is deteriorating. 1

Do Not Withhold Thrombolysis for Relative Contraindications

The 2003 British Thoracic Society guidelines explicitly state that contraindications should be ignored in life-threatening PE, as the mortality from untreated massive PE far exceeds bleeding risks. 1

Recognize Poor Prognosis in Out-of-Hospital Cardiac Arrest

Patients with out-of-hospital cardiac arrest due to PE rarely recover, even with thrombolysis. 1 This should inform discussions about resuscitation intensity and goals of care.

Evidence Quality Considerations

The 2021 CHEST guidelines demonstrate that thrombolysis in hemodynamically unstable PE reduces all-cause mortality by 20 fewer deaths per 1,000 cases, though it increases major bleeding by 65 events per 1,000 cases. 1 However, in the setting of sustained hypotension or shock, the mortality benefit clearly outweighs bleeding risk, with agreement among all major guideline panels. 1

The European Society of Cardiology, National Institute for Health and Care Excellence, and American College of Chest Physicians all recommend thrombolysis for high-risk (hemodynamically unstable) PE. 1, 3