What is the incidence and management of post-cardiotomy massive pulmonary embolus?

Incidence and Management of Post-Cardiotomy Massive Pulmonary Embolus

The incidence of massive pulmonary embolism after cardiac surgery is very rare, but carries high morbidity and mortality when it occurs, requiring prompt diagnosis and aggressive management with thrombolytic therapy, surgical embolectomy, or catheter-based interventions depending on patient stability and contraindications.

Incidence of Post-Cardiotomy PE

Pulmonary embolism (PE) following cardiac surgery is an uncommon complication:

• The general population incidence of PE is approximately 0.5 per 1000 people annually 1
• Post-cardiac surgery PE is rare but associated with high morbidity and mortality 2
• The exact incidence varies based on:
  • Postoperative thromboprophylaxis regimens
  • Presence of indwelling central venous catheters in lower extremities
  • Early ambulation protocols
  • Use of mechanical prophylaxis measures

Risk Factors for Post-Cardiotomy PE

Several factors increase the risk of PE following cardiac surgery:

• Prolonged immobilization
• Venous stasis during and after surgery
• Hypercoagulable state induced by surgical trauma
• Heparin-induced thrombocytopenia (occurs in approximately 3.8% of cardiac surgery patients) 2
• Slow postoperative recovery with delayed ambulation
• Pre-existing cardiac or pulmonary disease

Diagnostic Approach for Suspected Post-Cardiotomy PE

When massive PE is suspected after cardiac surgery, prompt diagnosis is crucial:

• For hemodynamically unstable patients with suspected massive PE:

  • Echocardiography is the most useful initial test, showing indirect signs of acute pulmonary hypertension and right ventricular overload 1
  • In highly unstable patients, treatment may be initiated based on compatible echocardiographic findings alone 1

• For stabilized patients:

  • Definitive diagnosis should be sought through perfusion lung scan, spiral CT angiography, or bedside transesophageal echocardiography 1
  • A normal lung scan or CT angiogram should prompt search for another cause of shock 1

Management of Post-Cardiotomy Massive PE

1. Initial Stabilization

• Hemodynamic and respiratory support is critical 1
• Avoid excessive fluid loading as it may worsen hemodynamic status 1
• Consider vasopressors and inotropes to support circulation

2. Thrombolytic Therapy

• Unless absolutely contraindicated, thrombolysis should be given to all patients with massive PE (defined as PE with shock and/or hypotension) 1
• Most contraindications for thrombolytic therapy in massive PE are considered relative, especially when weighing against the high mortality risk 1
• Recent cardiac surgery is typically considered a relative contraindication to thrombolysis due to bleeding risk

3. Surgical Pulmonary Embolectomy

• Indicated for three patient categories 1:

  • Patients with acute, massive PE
  • Patients with contraindications to thrombolytic treatment
  • Patients who lack response to intensive medical treatment and thrombolysis

• Surgical technique 1:

  • Median sternotomy
  • Rapid cannulation of ascending aorta and right atrium
  • Institution of normothermic cardiopulmonary bypass
  • Avoidance of aortic cross-clamping
  • Removal of emboli via longitudinal incision in main pulmonary artery

• Outcomes of surgical intervention:

  • In a series of patients requiring CPR for massive PE, surgical management improved early survival rates 3
  • Surgical pulmonary embolectomy has shown low morbidity and mortality rates with preserved improvement in right ventricular function 4
  • For post-coronary bypass patients specifically, emergency pulmonary embolectomy with cardiopulmonary bypass has been reported as an effective approach 5

4. Catheter-Based Interventions

• Indicated when thrombolysis is contraindicated or has failed, or when surgical embolectomy is unavailable 1

• Three general categories of percutaneous intervention 1:

  • Aspiration thrombectomy
  • Thrombus fragmentation
  • Rheolytic thrombectomy

• Clinical success rates 1:

  • 81% with percutaneous therapy alone
  • 95% when combined with local infusion of thrombolytic agents

Prevention of Post-Cardiotomy PE

• Routine use of graduated compression stockings
• Early ambulation when possible
• Consider sequential compression devices in non-ambulatory patients
• Aspirin therapy (standard post-CABG)
• For high-risk, non-ambulatory patients, consider pharmacologic prophylaxis (though further data needed to support this approach) 2

Key Considerations for Post-Cardiotomy PE

1. Rapid diagnosis and intervention are critical for survival in massive PE

2. The choice between thrombolysis, surgical embolectomy, or catheter-based intervention should be based on:

   • Patient hemodynamic stability
   • Contraindications to thrombolysis
   • Availability of surgical or catheter-based interventions
   • Institutional expertise

3. Institutions should have protocols in place for rapid transfer to centers with advanced intervention capabilities when needed 1