Varicose Veins, Blood Clots and the Heart: What Large Studies Show
Large population studies show that people with varicose veins have more deep vein thrombosis (DVT), and to a lesser degree more heart and artery disease, than people without them. That is an association, not proof that the veins cause either. The clot link is the stronger one; the heart link is weaker and may run in both directions.
Is that a reason to worry? For most people, no. It is one of the questions I am asked most often after a scan in Dubai: are these veins a danger to the rest of my body, or only to my legs? This article sets out what the largest studies measured, why a link between two conditions does not mean one causes the other, and what the findings mean for you. For where the leak in the vein begins, see why varicose veins form; for the condition and the treatments available, see varicose veins treatment.
Association or Cause: How to Read a Large Study
Most of this evidence comes from cohort studies. Researchers take a large group of people, record who has varicose veins, and count who later develops a clot or heart disease. The result is usually given as a hazard ratio. A hazard ratio of 2 means the event happened twice as often in the group with varicose veins over the same period.
A hazard ratio cannot say why. Three things can produce a link without one condition causing the other:
Shared risk factors. Age, excess weight, high blood pressure and smoking raise the chance of both venous and heart disease. A large German population study identified these among the determinants of chronic venous insufficiency.
Closer attention. People diagnosed with varicose veins see doctors and have scans more often, so a clot is more likely to be found and recorded.
Reverse direction. A failing heart raises the pressure in the leg veins, so in some people the heart problem may come first.
How do researchers get closer to cause? One method is Mendelian randomisation. It uses gene variants that make varicose veins more likely, fixed at conception and not shaped by weight, work or lifestyle. If carriers also have more clots, the veins themselves are more likely to play a part. Neither method is perfect, but when the two disagree, the gap is informative.
The Clot Evidence: A Fivefold Difference in Diagnosed DVT
The NHS lists varicose veins among the factors that make a DVT more likely. The largest study behind that link, published in JAMA in 2018, followed 212,984 adults with varicose veins in Taiwan's national insurance records and the same number of matched adults without them for about seven and a half years. DVT was diagnosed 5.3 times as often in the varicose veins group. Pulmonary embolism, a clot that has travelled to the lungs, was 1.7 times as common, and so was peripheral artery disease.
Absolute numbers are more useful than relative ones. The study recorded about 6.5 DVTs per 1,000 people with varicose veins each year, against 1.2 per 1,000 without, so in any one year more than 99 in 100 people with varicose veins had no DVT diagnosed. The authors cautioned that the findings for pulmonary embolism and artery disease could reflect confounding, and that whether the DVT link is causal, or reflects a common set of risk factors, needs further research.
Genetic evidence points the same way, but more modestly. A 2022 Mendelian randomisation study using UK Biobank and FinnGen data found that a genetic tendency to varicose veins raised the odds of DVT by roughly 17 per cent, and the effect held after allowing for body weight and height. It found no such effect for pulmonary embolism. The two studies measure different things and cannot be compared directly. Read together, they suggest that much of the fivefold figure comes from shared risk factors and closer medical attention, while a smaller, direct contribution from the veins remains plausible.
A 2026 systematic review in the European Journal of Vascular and Endovascular Surgery combined seven studies of 3.76 million people. Unadjusted, DVT was about five times as common (risk ratio 5.23). Where other risk factors were allowed for, in two studies, the hazard ratio for any venous clot fell to 1.76, just short of statistical significance, evidence the authors rated very low certainty.
Clots inside the varicose veins themselves matter too. A hard, red, tender cord along a varicose vein is superficial vein thrombosis, often called thrombophlebitis. In a French study of 844 people with superficial vein thrombosis in the leg, about 1 in 4 (24.9 per cent) already had a DVT or a pulmonary embolism when they were scanned.
NICE guidance on varicose veins recommends referral to a vascular service for superficial vein thrombosis with suspected venous incompetence, and asks clinicians to explain the possible complications of varicose veins, DVT among them, while addressing misconceptions about how likely those complications are. Dr. Sohrabi's practice follows that guidance.
The clot risk around a procedure, who carries more of it, and whether the lower clot rates seen after treatment in recent record studies are real, are covered in does treating varicose veins lower your clot risk. For the symptoms, scanning and treatment of a clot in the deep veins, see deep vein thrombosis.
The Heart Evidence: Weaker, and Possibly Two-Way
Does the link reach the heart? The strongest population data come from the Gutenberg Health Study in Germany, which graded the leg veins of 12,423 adults aged 40 to 80 using the CEAP system. Chronic venous insufficiency, the stage beyond simple varicose veins in which swelling or skin changes appear, was found in 40.8 per cent. It was associated with cardiovascular risk factors and disease, and over 6.4 years it predicted death from any cause (hazard ratio 1.46) independently of the other risk factors measured. A second cohort repeated it (1.51), as reported in the European Heart Journal in 2021.
Heart failure has been studied more narrowly. A South Korean cohort of 390,436 people, followed for a median of 13.3 years, recorded heart failure about 17 per cent more often in people with varicose veins. Two 2024 Mendelian randomisation studies, built to test cause, found either no effect on heart failure or a very small one.
The likeliest reading is that venous and heart disease share roots, and that a struggling heart can worsen the veins, rather than varicose veins damaging the heart. The studies and the possible mechanisms are examined in varicose veins and heart failure.
Four Practical Points for Anyone With Varicose Veins
Treat varicose veins as a marker, not a verdict.
Know the signs of a DVT. Throbbing pain and swelling in one leg, usually the calf or thigh, with warm or darkened skin over the area, needs assessment the same day. Breathlessness or chest pain alongside those signs is an emergency; in the UAE, call 998 for an ambulance.
A hard, painful varicose vein deserves a scan. Given the 1 in 4 figure, a surface clot is a reason to check the deep veins, not just to apply a cream.
Swelling in both ankles with breathlessness points to the heart. The NHS lists swelling in the feet, ankles or legs among the main symptoms of heart failure, alongside breathlessness during everyday activity or when lying down. When varicose veins come with that combination, Dr. Sohrabi arranges an echocardiogram, an ultrasound scan of the heart, and a referral to a cardiologist; other tests may become necessary.
The shared risk factors are the ones you can change. Weight, blood pressure and smoking appear on both sides of the link. If you fly long-haul often, as many Dubai residents do, varicose veins are one more item on a clot risk list that includes a previous DVT, recent surgery, pregnancy and cancer.
Choosing a Surgeon to Assess Clot Risk in Varicose Veins
What should you look for? Specialist vascular training, and a surgeon who examines the deep veins as well as the surface ones. Dr. Sohrabi completed full specialist vascular training in the UK National Health Service, holds the FRCS in Vascular Surgery and a CCT, and performs and interprets his own duplex scans, which check the deep veins for clot as well as the surface veins for reflux.
Dr. Soroush Sohrabi is a UK-trained Consultant Vascular and Endovascular Surgeon (FRCS, CCT) practising in Dubai, with a Cleveland Clinic Advanced Endovascular Fellowship and 77 peer-reviewed publications.
Book a consultation to have your veins, and your clot risk, assessed.
Frequently Asked Questions
Can varicose veins cause a stroke or a heart attack?
There is no good evidence that they do. A 2024 Mendelian randomisation study found no causal link between venous insufficiency and stroke, heart attack or coronary artery disease. The Taiwanese cohort did record more peripheral artery disease in people with varicose veins, but its authors cautioned that this may reflect shared risk factors.
Can a clot in a varicose vein travel to the lungs?
Rarely, and usually by spreading into a deep vein first. In the French study of superficial vein thrombosis, 600 people had no deep clot when first scanned; within three months, 2.8 per cent developed a DVT and 0.5 per cent a pulmonary embolism, even though most had received anticoagulant treatment. This is why a surface clot is assessed with a scan rather than treated as a minor skin problem.
Do varicose veins shorten life expectancy?
The mortality finding in the Gutenberg Health Study was reported for chronic venous insufficiency, the more advanced stage with swelling or skin changes, and it was an association measured alongside other risk factors. A 2026 meta-analysis of five studies put the excess in deaths from any cause at about 30 per cent. That marks a group with poorer overall cardiovascular health. We found no randomised trial of whether treating the veins changes survival. A 2025 study of 463,313 health records found about half the death rate after a vein procedure, but treated people may have been healthier to begin with, and the authors called for randomised trials.
Do studies from Taiwan, Korea and Germany apply to patients in the UAE?
Broadly, with caution. The biology of vein valves and blood clotting does not change with geography, but each study drew on one national population, and the UAE's mix of nationalities, ages and risk factors is different. We found no large Gulf study that has followed people with varicose veins over time for clots or heart disease. In a smaller Riyadh case-control study of 380 women, gross varicose veins were among the strongest predictors of a clot in pregnancy, alongside a family history of clots and thrombophilia, an inherited or acquired tendency to clot.
About the Author
Dr. Soroush Sohrabi MD, PhD, FRCS, CCT (UK), PGCert, MCPhleb is a Consultant Vascular and Endovascular Surgeon practising in Dubai. He trained in the United Kingdom and holds a Fellowship of the Royal College of Surgeons (FRCS) in Vascular Surgery and a Certificate of Completion of Training (CCT). He has published 77 peer-reviewed papers with over 1,183 academic citations and is a member of the European Society for Vascular Surgery (ESVS) and the Vascular Society of Great Britain and Ireland (VSGBI). He is licensed by the UK General Medical Council (GMC No. 5207627) and the Dubai Health Authority (DHA No. 48905551).
Medically reviewed by Dr. Soroush Sohrabi MD, PhD, FRCS, CCT, Consultant Vascular and Endovascular Surgeon, October 2026.
References
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