What is the best management approach for an elderly female patient with subsegmental bilateral pulmonary embolism (PE), multiple myeloma, iron deficiency, and a left mediastinal posterior mass, presenting with shortness of breath and no evidence of heart strain?

Management of Subsegmental Bilateral PE in an Elderly Female with Multiple Myeloma

This patient requires immediate anticoagulation with low-molecular-weight heparin (LMWH) and hospital admission given her active malignancy, symptomatic presentation with shortness of breath, and multiple risk factors for recurrent venous thromboembolism. 1

Immediate Anticoagulation Strategy

Initiate therapeutic anticoagulation immediately while completing the diagnostic workup, unless active bleeding or absolute contraindications exist. 1

• Start enoxaparin 1 mg/kg subcutaneously every 12 hours as the preferred agent for cancer-associated thrombosis 1, 2
• LMWH is superior to vitamin K antagonists in cancer patients and should be continued for at least the first 6 months 1
• The presence of active multiple myeloma makes this a cancer-associated thrombosis requiring extended anticoagulation 1

Why Anticoagulation is Mandatory Despite Subsegmental Location

While subsegmental PE management remains controversial, anticoagulation is required in this case for several critical reasons:

• Active malignancy (multiple myeloma) dramatically increases VTE recurrence risk and is an absolute indication for treatment regardless of PE location 1, 3
• Symptomatic presentation with shortness of breath requiring admission indicates clinically significant disease 1, 3
• Multiple myeloma creates a hypercoagulable state with documented risk of bilateral pulmonary artery thrombosis and sudden death 4, 5
• The 2019 ESC guidelines note that withholding anticoagulation for subsegmental PE should only be considered in highly selected low-risk patients without cancer or symptoms 1
• Recent prospective data showed higher-than-acceptable VTE recurrence rates when subsegmental PE was left untreated, even in low-risk patients 6

Risk Stratification and Monitoring

This patient is at minimum intermediate-risk, not low-risk, based on her clinical profile: 1, 7

• Assess for right ventricular strain with bedside echocardiography (already reported as absent, which is favorable) 1
• Check troponin and BNP/NT-proBNP levels to further stratify risk 1, 7
• Monitor vital signs closely for hemodynamic deterioration 7
• No evidence of heart strain places her in the intermediate-low risk category, not requiring reperfusion therapy 1

Hospital Admission Rationale

Admission is appropriate rather than outpatient management because: 3

• Symptomatic presentation requiring evaluation of shortness of breath etiology 3
• Active malignancy with mediastinal mass requiring assessment of contribution to symptoms 3
• Iron deficiency anemia may complicate bleeding risk assessment on anticoagulation 1
• Need to exclude proximal deep vein thrombosis with compression ultrasonography of lower extremities 1
• Multivariate analysis shows that cancer patients with hypoxemia, comorbidities, and PE location require admission 3

Duration and Type of Anticoagulation

Extended anticoagulation is required given the active malignancy: 1

• Continue LMWH (enoxaparin 1 mg/kg every 12 hours) for at least 6 months 1, 2
• After 6 months, consider edoxaban or rivaroxaban as alternatives to LMWH, but avoid these if gastrointestinal involvement of myeloma exists due to increased bleeding risk 1
• Anticoagulation should continue indefinitely or until the cancer is cured, with periodic reassessment of risk-benefit ratio 1
• The lifelong VTE recurrence risk in cancer patients necessitates ongoing treatment 1

Critical Pitfalls to Avoid

Do not withhold anticoagulation based solely on subsegmental location in a cancer patient: 1

• The 2019 ESC guidelines specifically state that optimal management of subsegmental PE remains controversial, and false-positive findings should be considered 1
• However, bilateral subsegmental PE in a symptomatic cancer patient is not a candidate for watchful waiting 1
• Multiple myeloma patients have documented risk of fatal bilateral pulmonary thromboembolism 4
• Failure to anticoagulate cancer patients with PE, even incidental PE, increases mortality 3

Avoid aggressive fluid resuscitation if hemodynamic compromise develops, as this worsens right ventricular function; use norepinephrine as the vasopressor of choice 7

Follow-up and Long-term Considerations

Schedule follow-up within 1-2 weeks of discharge and comprehensive reassessment at 6-12 weeks: 8

• Evaluate for persistent dyspnea or functional limitation that could indicate chronic thromboembolic disease 1
• Multiple myeloma patients are at risk for pulmonary hypertension from multiple mechanisms including disease-specific factors and treatment toxicity 5
• Screen for chronic thromboembolic pulmonary hypertension (CTEPH) if symptoms persist beyond 3 months 1, 8
• Continue oncology follow-up for multiple myeloma management, as disease control impacts thrombotic risk 1, 5