To whom should a patient with a deep vein thrombosis (DVT) in the leg, potentially with a history of cancer or being elderly, be referred for evaluation and treatment?

Referral for Deep Vein Thrombosis (DVT) in the Leg

For most patients with confirmed DVT in the leg, referral to a vascular medicine specialist, hematologist, or thrombosis clinic is appropriate for anticoagulation management, while cancer patients with DVT should be referred to a hematologist or oncology team experienced in cancer-associated thrombosis. 1, 2

Initial Management and Referral Pathways

For Non-Cancer Patients with DVT

• Primary care physicians or emergency medicine physicians can initiate anticoagulation immediately with direct oral anticoagulants (DOACs) such as rivaroxaban or apixaban without requiring initial parenteral therapy, or with low-molecular-weight heparin (LMWH) followed by warfarin 1, 3

• Referral to vascular medicine or a thrombosis clinic is recommended for patients requiring extended anticoagulation decisions beyond 3 months, particularly those with unprovoked DVT, recurrent DVT, or complex bleeding risk profiles 2, 4

• Hematology consultation should be obtained for patients with suspected thrombophilia (recurrent unprovoked DVT, family history, young age <50 years, unusual clot locations) to guide duration of anticoagulation 1, 4

For Cancer Patients with DVT

• Immediate referral to hematology or the oncology team is essential because cancer-associated DVT requires different management than non-cancer DVT, with extended anticoagulation recommended regardless of bleeding risk 1, 2

• Cancer patients should receive LMWH as preferred initial and long-term therapy over warfarin or DOACs, though edoxaban (after 5 days of LMWH) or rivaroxaban may be considered if patients prefer oral therapy, with caution in gastrointestinal cancers due to higher bleeding risk 1, 3

• The NCCN guidelines recommend that cancer patients with DVT receive at least 6 months of anticoagulation, continuing indefinitely until resolution of active malignancy 1, 2

Specific Clinical Scenarios Requiring Specialist Referral

Proximal DVT (Popliteal Vein or Above)

• All patients with proximal DVT require anticoagulation and should be referred to specialists for management decisions regarding duration of therapy (3 months for provoked, extended for unprovoked) 1, 2

• Vascular surgery consultation may be needed for patients with acute iliofemoral DVT who are candidates for catheter-directed thrombolysis, particularly younger patients with good functional status and low bleeding risk 5

Distal DVT (Below Popliteal Vein)

• For isolated distal DVT without severe symptoms or extension risk factors, serial ultrasound imaging at 1-week intervals for 2 weeks can be performed by primary care with vascular medicine consultation if thrombus extends 1

• For isolated distal DVT with severe symptoms or risk factors for extension (active cancer, prior DVT, inpatient status, extensive clot burden, close to proximal veins), immediate anticoagulation and specialist referral is recommended 1

Elderly Patients

• Geriatric medicine or thrombosis clinic referral is appropriate for elderly patients (>75 years) due to higher bleeding risk with anticoagulation, requiring careful risk-benefit assessment and potentially dose-adjusted anticoagulation 1

• Bleeding risk assessment should include age >70 years, prior bleeding history, concomitant antiplatelet therapy, renal/hepatic impairment, and fall risk 2, 6

Urgent Referrals and Contraindications

When to Refer to Vascular Surgery Urgently

• Phlegmasia cerulea dolens (massive iliofemoral DVT with limb-threatening venous gangrene) requires immediate vascular surgery consultation for possible catheter-directed thrombolysis or thrombectomy 5

• Patients with contraindications to anticoagulation (active bleeding, recent surgery, severe thrombocytopenia <50,000/mcL) may require inferior vena cava filter placement by interventional radiology or vascular surgery 5

When to Refer to Hematology Urgently

• Heparin-induced thrombocytopenia (HIT) suspected (platelet drop >50% after starting heparin, new thrombosis on heparin) requires immediate hematology consultation for alternative anticoagulation with argatroban or fondaparinux 1

• Recurrent DVT despite therapeutic anticoagulation suggests need for hematology evaluation for underlying thrombophilia, malignancy screening, or consideration of increased intensity anticoagulation 1, 4

Common Pitfalls to Avoid

• Do not delay anticoagulation while awaiting specialist consultation in confirmed DVT—treatment should begin immediately in the emergency department or primary care setting unless absolute contraindications exist 1

• Do not assume bilateral leg edema excludes DVT in cancer patients—44% of cancer patients with positive DVT scans presented with bilateral asymmetric edema, and venous duplex ultrasound should be performed 7

• Do not discontinue anticoagulation for minor bleeding such as hematuria with urinary tract infection—treat the infection, continue anticoagulation, and perform urological evaluation to rule out underlying pathology 6

• Do not use DOACs in pregnancy—these patients require LMWH throughout pregnancy and should be co-managed with maternal-fetal medicine and hematology 1, 3