Why Is This Important?
When it comes to surgery, most people know something about the procedure itself. But "surgery was successful, yet the patient died on day 4" — is this really possible outside of extreme cases or dark humor?
As an anesthesiologist, I can tell you: this scenario is not uncommon at all. According to the American Heart Association, based on contemporary data from the ACS National Surgical Quality Improvement Program, the incidence of symptomatic VTE within 90 days after surgery is 0.5%–1.6%.
To prevent this, both domestic and international medical communities have standardized protocols — yet this knowledge remains largely unknown to patients and is too easily overlooked.
What Is Venous Thromboembolism (VTE)?
Venous thromboembolism (VTE) encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE). Think of them as different stages of the same disease: DVT is a common postoperative complication, while PE is one of the leading causes of sudden in-hospital death after surgery.
Deep Vein Thrombosis (DVT)
DVT occurs when blood abnormally clots within veins, causing venous return obstruction. It most commonly affects the legs.
Symptoms to watch for:
- Swelling in one leg (especially the calf)
- Pain or tenderness, often starting in the calf
- Warmth and redness in the affected area
- Visible surface veins
Pulmonary Embolism (PE)
When a blood clot from a deep vein breaks loose and travels to the lungs, blocking a pulmonary artery, it becomes a pulmonary embolism. This is a medical emergency that can be fatal.
Warning signs:
- Sudden shortness of breath
- Chest pain (worse with deep breathing)
- Rapid heart rate
- Coughing up blood
- Lightheadedness or fainting
Why Are Surgical Patients at High Risk?
German pathologist Rudolf Virchow proposed the classic theory of thrombosis, identifying three core elements — known as Virchow's Triad:
| Factor | How Surgery Contributes |
|---|---|
| Blood Stasis | Limited mobility during and after surgery slows blood flow, especially in the lower extremities |
| Hypercoagulability | Surgical trauma activates the body's clotting mechanisms |
| Endothelial Injury | Surgery directly damages blood vessel walls, triggering clot formation |
Additional Risk Factors
Beyond the surgical procedure itself, these factors increase perioperative VTE risk:
- Family history of venous thromboembolism
- Overweight or obesity
- Pregnancy and the postpartum period
- Smoking
- Medications (oral contraceptives, hormone replacement therapy)
- Surgery type (vascular surgery, joint replacement, and cancer surgery carry higher risk)
- Malignant tumors (cancer patients often have coagulation abnormalities with hypercoagulable states)
This explains why some patients recover uneventfully while others face life-threatening complications.
How to Prevent Perioperative VTE
Medical teams assess each patient's thrombosis risk and implement appropriate preventive measures. Patient participation is equally important.
Before Surgery
- Provide complete medical history for accurate risk assessment
- Report all medications you're currently taking
- Stay active — maintain mobility as much as possible
- Stay hydrated — drink plenty of water, avoid alcohol and dehydration
- Stop smoking (as far in advance as possible)
- Maintain healthy weight — if time permits, actively pursue weight loss
- Discuss VTE prevention strategy with your surgical team
After Surgery
The most effective way to prevent blood clots is to keep moving. Under your doctor's guidance, begin mobilization as early as possible.
If you truly cannot get out of bed, perform these exercises in bed:
1. Ankle Pump Exercises
These can be done lying down or sitting with legs extended:
- Plantar flexion: Slowly point your toes forward, stretching the top of your foot
- Dorsiflexion: Pull your toes back toward your head as far as possible
Alternate these movements 10–30 times per set, 3–5 sets daily. Patients who cannot walk at all should perform these hourly. Maintain normal breathing throughout — don't rush.
Tip: Ankle pump exercises are also excellent during long flights, train rides, or extended periods of sitting at work.
Note: Patients who have had lower extremity surgery should perform these only under medical guidance.
2. Stay Hydrated
Drink adequate fluids to prevent dehydration (IV fluids may be administered if necessary).
3. Mechanical Prevention (If Assessed as Needed)
Compression Stockings: Used for primary prevention of lower extremity DVT. They apply graduated pressure to help blood return to the heart.
Important: Use medical-grade stockings in the correct size. Not suitable for patients with peripheral arterial disease or leg skin lesions.
Intermittent Pneumatic Compression (IPC) Devices: These devices and foot pumps must be used under medical supervision with properly calibrated pressure settings.
4. Pharmacological Prevention
Your surgeon will determine whether anticoagulation medication is needed, balancing thrombosis risk against bleeding risk. For high-risk patients, anticoagulation may continue after discharge.
Common anticoagulant medications (if prescribed at discharge, take them seriously):
- Low-molecular-weight heparin (LMWH)
- Direct oral anticoagulants (DOACs)
- Warfarin
Family members should help ensure medication compliance and attend scheduled coagulation monitoring appointments.
When to Seek Emergency Medical Care
If You Suspect DVT:
- Stop all activity immediately — immobilize the affected limb
- Do NOT massage the affected leg
- Elevate the limb above heart level
- Wait for medical transport — do not walk to the hospital
If You Notice Bleeding Signs While on Anticoagulants:
Contact your medical team immediately if you experience unusual bruising, blood in urine or stool, or prolonged bleeding from minor cuts.
Key Takeaways
| Topic | Key Point |
|---|---|
| What is VTE? | Blood clots in deep veins (DVT) that can travel to lungs (PE) |
| Incidence | 0.5%–1.6% within 90 days post-surgery |
| Why surgery increases risk | Immobility + hypercoagulability + vessel damage (Virchow's Triad) |
| Best prevention | Early mobilization — ankle pumps, walking as soon as allowed |
| Emergency signs | Leg swelling/pain (DVT) or sudden breathlessness/chest pain (PE) |
FAQ
Q: How soon after surgery should I start moving? A: As early as your surgeon allows — often within hours of surgery. Even simple ankle pump exercises in bed significantly reduce VTE risk. The key principle is: movement is the most cost-effective prevention.
Q: Do compression stockings really help prevent blood clots? A: Yes, medical-grade graduated compression stockings are evidence-based for DVT prevention. They must be properly fitted and medical-grade — regular socks won't work. They're not suitable for patients with arterial disease.
Q: If I'm taking blood thinners after surgery, what should I watch for? A: Monitor for signs of excessive bleeding: unusual bruising, blood in urine/stool, bleeding gums, or prolonged bleeding from cuts. Take medications exactly as prescribed and attend all follow-up appointments for coagulation monitoring.
Q: Are certain surgeries more dangerous for blood clots? A: Yes. Joint replacement surgery, vascular surgery, cancer surgery, and any procedure requiring prolonged immobilization carry higher VTE risk. Your surgical team will adjust prevention strategies accordingly.
References
- Romero CS, Afshari A, Südy R, Samama CM. European guidelines on peri-operative venous thromboembolism prophylaxis. European Journal of Anaesthesiology. 2024;41(8):549-560.
- Chinese Society of Surgery. Guidelines for Perioperative Thrombosis Prevention and Management in General Surgery. Chinese Journal of Surgery. 2016;54(05):321-327.
- Bartlett MA, Mauck KF, Stephenson CR, Ganesh R, Daniels PR. Perioperative Venous Thromboembolism Prophylaxis. Mayo Clin Proc. 2020;95(12):2775-2798.
- Lip GYH, Stevens SM. Overview of the treatment of lower extremity deep vein thrombosis (DVT). UpToDate. 2025.
