A blood clot in the lungs after surgery is a relatively common but serious complication of surgery. In the last 15 years, I have been personally consulted by surgeons many times to treat a blood clot in the lungs after surgery. I am writing this article based on my personal experience as well as a review of all relevant medical research articles.
In this article, I will focus on these aspects of blood clot in the lungs after surgery:
- How common a blood clot is
- Risk factors for blood clots
- Symptoms of blood clots
- Prevention of blood clots
- Treatment of blood clots
How common is a blood clot in the lungs after surgery?
Fortunately, blood clots in the lungs after surgery is less common in 2020 because of preventive measures and guidelines developed over the last two decades. However, it still happens today. The exact number varies based on the particular study, but the rate of a blood clot in the lungs after a major surgery used to be as high as 10%-40%. Currently, it is estimated at around 1% to 2%.
One Japanese study in 2017 did an extensive review of the rate of blood clots in the lungs.
Here are the chances of a blood clot in the lungs after different types of surgery:
- After brain surgery: 1.1%
- After back surgery: 1.2%
- After heart or vascular surgery: 0.8%
- After hip or knee surgery: 3.3%
- After head or neck surgery: 0.6%
- After chest surgery: 0.9%
As you can see, the highest risk of a blood clot in the lungs is after hip or knee surgery. In fact, any surgery involving your bones carries a significant risk of blood clots. Tissues and bone injuries involved in orthopedic surgery release chemicals that significantly activate clotting factors in the blood. Bone surgeries also greatly reduce your mobility and make you vulnerable to having all kinds of blood clots, including a blood clot in the lungs.
The risk of blood clots in the lungs after surgery also depends on the duration of anesthesia required for the surgery. Here is what they found:
- Blood clot in the lungs after a surgery that required more than 6 hours of anesthesia: 1.7%
- Blood clot in the lungs after a surgery that required more than 3 hours but less than 6 hours of anesthesia: 1.3%
- Blood clot in the lungs after a surgery that required less than 3 hours of anesthesia: 0.4%
What are the other risk factors for getting blood clots in the lungs after surgery?
There are many other risk factors for getting a blood clot in the lungs after surgery. Here are some of those:
- Age: The older you are, the greater your risk of getting a blood clot in the lungs after any surgery. The risk is significantly higher in people 80 years and older.
- Being overweight: The higher your BMI (Body mass index: a measure of your body size based on your height and weight), the greater your risk of having a blood clot in the lungs after surgery.
- History of previous blood clots
- History of cancer
- Presence of an infection
- Certain abnormalities in the blood clotting system
- History of inflammatory diseases
Symptoms of blood clots in the lungs after surgery
It is important to know that many patients have no symptoms when they have a blood clot in the lungs. However, patient who have symptoms have a worse outcome than those without any symptoms. In the above mentioned Japanese study, patients who had symptoms had a mortality rate of 4.2% compared to all patients diagnosed with blood clots in the lungs after surgery.
Although you can have a blood clot in the lungs after surgery without any symptoms, it is important to pay attention to these symptoms because they indicate worse outcomes.
Here is the list of signs and symptoms:
- Finding low oxygen on the monitor
- New sharp chest pain, usually worse with a cough or deep breaths
- Increased heart rate
- Fast breathing
- New or worsening shortness of breath
- Suddenly feeling dizzy or lightheaded
- Sudden cardiac arrest
Unfortunately, a sudden cardiac arrest is one of the symptoms of blood clots in the lungs after surgery. A cardiac arrest from a blood clot is very difficult to revive even when CPR and advanced life-saving measures are started right away.
How do you prevent blood clots in the lungs after a surgery?
The first step to prevent a blood clot in the lungs after any surgery is to identify patients at risk. Every hospital system in the United States is supposed to use one of the risk-scoring systems to identify who is at a higher risk of having a blood clot after surgery. Depending on the risk, one or more of the following preventative measures are taken:
- Use of blood thinners: Blood thinners help prevent blood clots in the lungs after surgery. It is important to get blood thinners started as soon as it is safe to do so. Blood thinners are recommended in most cases, unless these is active bleeding or a very high risk of bleeding. An injectable blood thinner called Low Molecular Weight Heparin (LMWH) is the most commonly used blood thinner in the hospital, and it has a good track record.
- Mechanical compression device: In situations where blood thinners can’t be used due to active bleeding or very high bleeding risks, they use a device that wraps around your legs. These devices compress and relax around your legs at regular intervals to help increase the flow of blood in your leg veins and prevent clot formation.
Treatment of blood clots in the lungs after surgery
The treatment of a blood clot in the lungs after surgery depends on the severity of the symptoms. High-risk patients need specialized treatment. You are at a high risk for complications or death from blood clots in lungs after surgery if you have these signs or symptoms:
- Low blood pressure
- Sudden collapse
- Cardiac arrest
If you have any of those signs or symptoms, you may need clot-busting medications to try to dissolve the blood clots in your lungs. Clot-busting medications are different from blood thinners. Blood thinners simply inhibit your body’s natural clotting mechanism and prevent the clot from getting bigger. This also prevents new clots. Clot-busting medications, on the other hand, dissolve the clot directly. Clot-busting medications have a much higher risk of bleeding compared to blood thinners. They are reserved for life-threatening situations such as this.
Unfortunately, many patients who develop a blood clot in the lungs after surgery can’t get the clot-busting medications because they have a very high risk of bleeding at the surgical site. For example, if someone had a brain surgery, the risk of dying from brain bleed is too high to use clot-busting medications.
Recently, there are some advanced treatment options that may be helpful in these types of situations. Patients have some success with a procedure called catheter guided mechanical thrombectomy. It is a method of removing the clots with a small tube inserted into the body and guided under an x-ray to reach the site of the clots. They can remove the clots in some patients and save lives in certain septic situations.
The other option in high-risk patients is an open surgery to remove and retrieve the clots. This surgery carries about a 10% risk of death and is only performed when the risk of death from the clot is even higher.
In medium-to-low risk patients with blood clots in the lungs after surgery, the usual treatment is still blood thinners, not clot-busting medications. For treatment of blood clots, a higher dose of the same injectable Low Molecular Weight Heparin (LMWH) that is used to prevent clots can be used.
In conclusion, a blood clot in the lungs is less common these days due to universal prevention measures. You still need to look for symptoms of blood clots in the lungs after surgery in high-risk situations because it can have devastating consequences.