What percentage of patients with upper extremity Deep Vein Thrombosis (DVT) have an occult Pulmonary Embolism (PE)?

Upper Extremity DVT and Occult Pulmonary Embolism

Approximately 40% of patients with upper extremity deep vein thrombosis (UEDVT) have an occult pulmonary embolism (PE). 1

Epidemiology and Risk

Upper extremity DVT has become increasingly common in recent years, primarily due to:

• Increased use of invasive diagnostic and therapeutic procedures
• Indwelling venous catheters
• Intravenous chemotherapeutic agents 1

While UEDVT accounts for only 10-20% of all DVT cases, its association with PE is significant and often underappreciated 1, 2.

Comparison to Lower Extremity DVT

The risk of PE from UEDVT differs from lower extremity DVT:

• Lower extremity DVT:

  • 46% PE incidence if confined to calf
  • 67% PE incidence with thigh involvement
  • 77% PE incidence with pelvic vein involvement 1

• Upper extremity DVT:

  • Up to 40% PE incidence overall 1

Risk Stratification by UEDVT Type

The risk of PE varies by UEDVT etiology:

1. Catheter-related UEDVT:

   • Highest risk at approximately 17% (95% CI: 7-32%) 3
   • Relative risk 3.4 times higher compared to other causes 3
   • In prospective evaluation, catheter-related UEDVT showed higher PE rates than primary UEDVT 4

2. Primary/Idiopathic UEDVT:

   • Lower risk at approximately 6% (95% CI: 0.2-30%) 3

3. Secondary non-catheter UEDVT:

   • Intermediate risk at approximately 13% (95% CI: 6-24%) 3

Detection Methods and Limitations

Many PEs associated with UEDVT are clinically silent and only detected through systematic screening:

• Prospective studies using routine ventilation-perfusion scanning show higher PE rates (17%, 95% CI: 12-23%) than retrospective studies (7%, 95% CI: 4-9%) 3
• This suggests many PEs are asymptomatic and only detected when actively sought

Clinical Implications

The high rate of occult PE in UEDVT patients has important implications:

1. Anticoagulation necessity: The 40% rate of PE justifies prompt anticoagulation for all UEDVT patients
2. Risk assessment: Patients with catheter-related UEDVT warrant particularly close monitoring
3. Diagnostic approach: Consider PE evaluation in UEDVT patients, especially those with catheter-related thrombosis

Pitfalls to Avoid

1. Underestimating risk: Don't assume UEDVT carries lower PE risk than lower extremity DVT
2. Focusing only on symptoms: Many PEs are asymptomatic but still clinically significant
3. Delaying treatment: The high PE rate justifies immediate anticoagulation upon UEDVT diagnosis
4. Overlooking catheter-related cases: These carry the highest PE risk and require vigilant management

The evidence clearly demonstrates that UEDVT represents a significant PE risk, with occult embolization occurring in approximately 40% of cases, highlighting the importance of appropriate evaluation and management of these patients.