Blood Clot FAQs
Published on: 04/04/2022
/ By Vascular Cures Team

Q&A with vascular surgery specialist, Dr. Zayed

Vascular Cures is pleased to be bringing our community a Question & Answer piece featuring the expertise of one of our previous Wylie Scholars, Dr. Mohamed Zayed. We asked patients with a history of clotting to share some of the questions they have about blood clots. Dr. Zayed provides some insight and tackles the issues patients are most interested in hearing about below!

What is a blood clot?

What causes the harmful kind of clotting (e.g. excessive clotting)?

Blood clot formation is the body’s natural way to help seal blood vessel injuries. On a biological level, blood clots occur when components in the blood (such as platelets) stick to one another and cause semi-solid masses.  These masses can range from small microscopic fragments to large-volume cords within blood vessels. Large-volume blood clots can develop in the peripheral veins and lead to deep venous thrombosis (DVT).

Is there anything that increases the risk of clotting?

Certain risk factors can further promote the formation and extension of DVTs in veins. Large DVTs can lead to dislodgement and movement of the clot to other regions of the body (venous thromboembolism; VTE). One potentially fatal form of VTE is pulmonary emboli, where DVTs dislodge and move into the pulmonary arteries. Individuals who smoke, are obese, have acute infections (including COVID19), or have underlying genetic conditions may be at higher risk of DVT and PE. Pregnancy and prolonged bed rest can also lead to VTE, and preventative methods with regular walking and leg elevation can help decrease this risk.

How often do blood clots reoccur?

DVTs occur in nearly 1 million individuals in the US per year (1-2 individuals in every 1000). Progression of a DVT leading to VTE complications occurs in nearly 100 individuals per 100,000. Sudden death occurs in 25% of individuals that develop PE, and up to 30% die within 1 month. Key measures can be taken to prevent DVT extension and risk of VTE, including early and effective diagnosis, as well as treatment with blood-thinning medication.

Can you catch clots/the risk for clotting early? 

Individuals with risk factors for DVT can remain mindful of symptoms associated with DVTs, including extremity swelling, aching calf or lower leg pain that can be made worse with walking, or visible painful cords in superficial veins. The diagnosis of DVT can be confirmed with a non-invasive, fairly straightforward ultrasound, which helps detect clots within veins. Individuals with DVTs who develop sudden shortness of breath or chest pain can be immediately screened with a CT scan to find out if life-threatening PE is present.

Are there risks for pregnancy/giving birth for those who might have clotting issues (e.g. Factor V Leiden)? Who should be worried?

The risk of VTE is above average, but still uncommon among individuals who are pregnant. It is estimated that VTE occurs in 1 in 500-2000 pregnancies. The risk is increased in individuals with who are obese, recumbent, or have cardiovascular risk factors. An underlying genetic condition, such as Factor V Leiden) can also increase the risk of VTE. It is estimated that VTE occurs in 1 in 1000 individuals. The risk of blood clot formation increases with age, and sometimes needs treatment with preventative blood thinning medication.

How diligent should I be about symptoms? Is there a suggested way to monitor/track symptoms?

It is sometimes natural to develop some mild swelling in the lower extremities. However, if the symptoms are persistent, progressive, and/or associated with dull aching pains in the lower legs, calves, or behind the knees, then additional diagnostic testing would be beneficial.

I know misdiagnosis sometimes happens with blood clots – how can I make sure my doctor considers blood clots without being too dramatic (e.g. misinterpreting a cough)? 

If you have risk factors, discuss with your doctor ways to decrease these risk factors, as well as what DVT symptoms to be on the lookout for. Establishing this framework with your doctor will be valuable in your subsequent visits in case you develop any concerning symptoms. In the event that there are concerning symptoms, being mindful of when they occur, what alleviates and aggravates them, and other physical characteristics will help in your conversation with your doctor, and in your accurate and prompt diagnosis.

I’ve heard about DVT warning signs, but what about warning signs for clots outside of my legs? Are there signs for these other kinds of clots?

Individuals with DVT are at risk of developing life-threating PE, which in nearly 50% of individuals can manifest with sudden shortness of breath, shortness of breath with exertion, stabbing chest pains that are worse with breathing, feeling lightheadedness, or having heart palpitations or irregular heartbeats.

What can I do to lower my risk of blood clots?

First, recognition of your risk factors and how to decrease them is a key preventative point. This includes smoking cessation, appropriate weight management, regular exercise, and avoiding long periods of recumbency or lack of movement. On long car or plane rides, regular walking and stretching of the legs can help prevent venous stasis and blood clot formation. Individuals with underlying genetic predisposition factors, who have either had prior DVTs or will encounter episodes of planned recumbency (following surgery), may benefit for short treatment courses with blood thinners. 

What’s the most important thing to know about blood clots – what’s the take-home message to share with my family?

Prevention and early detection are key in the prevention of complications related to DVTs. If you or a family member are worried about your risk of DVT, please consult with your doctor and perform regular self-checks. 

Dr. Mohamed Zayed is a vascular surgery specialist at the Washington University School of Medicine in St. Louis. A previous Vascular Cures Wylie Scholar, Dr. Zayed is the director of the Zayed Lab, which has a special focus on the connection between diabetes and peripheral artery disease. 

Note: this blogpost was developed through a generous grant from Inari Medical.