Deep Vein Thrombosis in CVI

Chronic venous insufficiency (CVI) can increase the risk of blood clots in the legs due to impaired blood flow and venous pooling. This page explains clot risk, warning signs, and when medical evaluation or emergency care is needed.

Chronic Venous Insufficiency and Blood Clot Risk

Patients with chronic venous insufficiency (CVI) have an increased risk of developing deep vein thrombosis (DVT)—a blood clot that forms in the deep veins of the legs.

In CVI, damaged vein valves do not return blood efficiently back to the heart. This leads to blood pooling in the legs and slower blood flow. When blood flow becomes sluggish—especially during periods of limited movement or prolonged immobility—the risk of clot formation increases.

A DVT can sometimes travel to the lungs and cause a pulmonary embolism (PE), a serious medical emergency requiring immediate care.

Situations That Increase Blood Clot Risk

Blood clot risk is higher during periods of reduced leg movement, including:

• Long car rides or sitting in traffic for several hours
• Long-distance air travel
• Jobs that require prolonged sitting or standing
• Lower-extremity injuries requiring immobilization (casts or braces)
• Prolonged bed rest or reduced mobility

Risk-Reduction Strategies

To help reduce the risk of blood clots, patients may be advised to:

• Move and stretch the legs regularly
• Avoid prolonged immobility when possible
• Wear graduated compression stockings when recommended
• Follow medical and lifestyle recommendations provided by their physician

Deep Vein Thrombosis vs Superficial Thrombophlebitis

Blood clotting is a normal and essential process that prevents excessive bleeding. However, clots can sometimes form inside veins without obvious injury, leading to potentially serious complications.

Certain conditions and factors increase the risk of abnormal clot formation, including:

• Pregnancy, oral contraceptive use, smoking
• Obesity, diabetes, high blood pressure, and other chronic conditions
• Trauma, medical procedures, or surgery
• Family history or genetic predisposition to blood clots
• Chronic venous insufficiency and varicose veins
• Prolonged inactivity (desk work, long travel, bed rest, casts)

Superficial Thrombophlebitis (SVT)

Superficial thrombophlebitis is inflammation of a vein just beneath the skin, with or without a small blood clot.

• Usually less dangerous than DVT
• Often improves with appropriate medical care
• If untreated, clots in major superficial veins can extend into the deep venous system and progress to DVT

Deep Vein Thrombosis (DVT)

Deep vein thrombosis occurs when a blood clot forms in veins located deep within the leg muscles.

• More serious than superficial thrombophlebitis
• Carries a risk of pulmonary embolism
• Requires prompt medical evaluation and treatment

Shared Symptoms

Both SVT and DVT may cause:

• Leg pain or tenderness
• Swelling
• Redness or warmth of the skin

Pain severity alone cannot reliably distinguish between these conditions, as pain tolerance varies between individuals.

When to Seek Immediate Medical Attention

The only reliable way to determine whether a blood clot is superficial or deep is through a medical evaluation, often including duplex ultrasound and additional testing when indicated.

Call 911 or go to the emergency room immediately if leg symptoms are accompanied by:

• Shortness of breath
• Chest pain
• Pain with breathing
• Sudden coughing

These may be signs of a pulmonary embolism, which is a medical emergency.

Schedule a Vein Evaluation

If you have varicose veins, chronic venous insufficiency, or concerns about blood clot risk, professional evaluation is essential.

International Vein & Skin Institute
Dr. Jozef Tryzno, MD, RVT, DABVLM
📞 (847) 518-9999

Medical Information Disclosure
The information on this page is provided for general educational purposes only and is not intended to diagnose or treat any medical condition. Blood clot risk and symptoms vary by individual. If you have concerns about your health, a medical evaluation is required. In the event of sudden or severe symptoms, seek emergency medical care immediately.