- André Biernath – @andre_biernath
- From BBC News Brazil in London
Gone are the days when covid-19 was seen only as a respiratory disease. Nowadays, there is a consensus among experts that the repercussions of the coronavirus infection are not limited to the lungs and can affect many other parts of the body, especially the blood vessels.
The risk of developing a thrombosis — the formation of clots in veins and arteries that can block blood flow and interrupt the supply of oxygen and nutrients to organs — is much higher in infected patients, especially those with more serious conditions, who need treatment. admission to the Intensive Care Unit (ICU).
And, according to experts heard by BBC News Brasil, the probability of having this vascular complication during or after covid grows a little more in those people who have varicose veins, a condition marked by the dilation and deformation of the most superficial veins of the legs.
But what does one thing have to do with the other? And are there ways to prevent, detect early and treat covid-related thrombosis? To answer all these questions, we must first take a step back and understand how a virus that enters through the nose and mouth causes so many problems in the blood vessels.
Worse the amendment than the sonnet
Doctor Carlos Jardim, who works at the Pulmonology Division of the Instituto do Coração (InCor), in São Paulo, recalls that, at the beginning of the pandemic, the first suspicions arose that the coronavirus can affect veins and arteries.
“We began to see many thrombosis phenomena in patients who went to the ICU. The frequency was much higher than we had observed in other outbreaks of respiratory viruses, such as the H1N1 pandemic in 2009”, he says.
And the explanation for this has to do with an affinity that exists between Sars-CoV-2, the pathogen that causes covid, and the cells that form the inner layer of blood vessels, also known as the endothelium.
These endothelial cells are now known to have the receptors that the coronavirus attaches to to initiate infection. In practice, this means that it is also capable of wreaking havoc on this structure of the circulatory system.
“The endothelium needs to be very smooth, like the asphalt of a good road, so that the blood circulates without lumps”, explains pulmonologist Elnara Márcia Negri, from Hospital Sírio-Libanês, in São Paulo.
“What happens in covid is that the virus manages to invade these cells and puncture this internal asphalt of our vessels”, adds the doctor.
The body, in an attempt to stop this problem, starts a series of processes and one of them involves blood clotting. The idea is to create a protective barrier in the injured region, so that the endothelium can recover.
The problem is that, in a number of patients, the amendment ends up being worse than the sonnet. The clotting mechanism passes the point and generates a gelatinous mass of cells and fibers that can stop the flow of blood in that place or come loose and block the circulation in other organs. We’re talking about the thrombus here.
“It’s as if I repaired the wall of my house, but I exaggerated the cement layer so much that I can no longer open or close the door”, compares Jardim.
If the blockage occurs in the arteries of the heart, a heart attack occurs. If the phenomenon develops in any vessel of the head, we may have a cerebrovascular accident (CVA). Now, if the thrombus breaks loose and ends up in the lungs, we talk about an embolism. The three situations are very serious, with a high risk of death.
“To complete, the critically ill patient is usually sedated and intubated. And this lack of body movement for a prolonged period is another risk factor for thrombosis”, adds vascular surgeon Fábio Rossi, president of SBACV – Regional São Paulo. Paul.
Of 184 patients analyzed, 49% had thrombotic events. Of these, 87% were diagnosed with pulmonary embolism, 6.6% with stroke and 2.6% with arterial thrombosis.
Fortunately, the frequency of episodes of coronavirus-related thrombosis has been dropping in recent months.
“In our clinical practice, we have seen thrombotic events in 15% of patients, a number that has dropped to 2% more recently”, calculates Negri.
And this has to do with vaccines, which protect against the most serious forms of covid and its consequences throughout the body.
“The only patient that I had the misfortune to intubate in this current wave of the omicron had not been vaccinated”, reports the doctor.
And where do varicose veins enter this story?
Well, now that we understand the relationship between covid and thrombosis, it’s time to add a third ingredient: varicose veins.
First of all, it must be made clear that there are not many studies investigating this relationship. There is, for example, no calculation of the extra risk that carriers of this disease, marked by swollen and deformed veins in the legs, run of having thrombosis, if they are infected by the coronavirus.
And it is worth mentioning that the opposite path has not been observed so far: there is no scientific evidence that covid can be a trigger for the development of varicose veins.
For now, the appearance of varicose veins after covid is seen as an independent event and without a common denominator. In any case, it is worth looking for a doctor to evaluate the condition in a personalized way, if you have noticed something different in the blood vessels of the lower limbs.
The greater risk of thrombosis during or after covid among those who have varicose veins comes more from a practical observation of doctors who are specialists in this area.
And, even before the pandemic, it was already known that varicose veins are an independent risk factor for the development of thrombosis.
A study published in 2018 in the specialized journal Journal of the American Medical Association (Jama), for example, followed for seven and a half years more than 212 thousand individuals with varicose veins and another 212 thousand who do not have this problem.
When comparing the results of the two groups, researchers from the Medical University of China found that the risk of thrombosis is 5.3 times greater among people with varicose veins.
If we bring this information to the context of the pandemic, therefore, varicose veins can be an extra ingredient that, together with the action of the virus on the endothelium, the immobility of the ICU stay and the exaggerated clotting process, increases the likelihood of a thrombosis.
“The patient who has varicose veins and gets covid, therefore, has an extra risk of having this vascular complication”, concludes Rossi.
The good news is that there are ways to prevent, diagnose and treat these thrombotic events.
One of the first attitudes of specialists when they are faced with a more serious case of covid is to prescribe anticoagulant medication.
“It is worth clarifying here that these drugs are restricted to hospitals, applied through infusions or injections, and are not indicated for everyone who has become infected”, says Negri.
“And even when this patient who was more critical is discharged, it may be necessary for him to continue using oral anticoagulants for some time”, adds the doctor.
The purpose of this preventive treatment is to “hold the reins” of the clotting process and prevent the appearance of thrombi that clog the vessels.
When this strategy is not enough, it is important to be aware of the most frequent symptoms of this problem.
“The signs depend a lot on the affected area. If it is the brain, the individual may have mobility changes, difficulties in speaking or not being able to move a part of the body. Now, if the problem is concentrated in the lungs, he will feel short of breath and palpitation. If it appears on the legs, it can cause swelling and heat”, describes Jardim.
However, more than memorizing a list of symptoms, it is recommended that you quickly report any discomfort you feel to the health professional who follows the case – especially if you have varicose veins or know that close family members have had thrombosis in the past.
“The patient’s condition should also draw attention to the patient who, by the sixth or seventh day since the beginning of the symptoms of covid, begins to get worse and has body pain, fever, fatigue, shortness of breath…”, points out Negri.
“In this situation, it may be necessary to check that there is no risk of thrombosis.”
From the initial suspicion, it is possible to use a series of blood and imaging tests (such as ultrasound and tomography) to make the proper diagnosis.
Still in this area, another essential requirement is agility: if the thrombus is blocking a more important vein or artery, the faster this is detected and treated, the better the prognosis.
“Quick care makes all the difference. Some tissues of our body, such as the brain and heart, last a short time if they are deprived of blood”, explains Jardim.
If the test reports even identify a thrombosis, the next step is to prescribe some drugs from the anticoagulant class, which prevent the appearance of new clots, and thrombolytics, which help to dissolve the already installed thrombus.
In some cases, it is necessary to resort to surgeries that unclog the obstructed vessel with the help of catheters and other equipment.
Finally, one cannot forget the attitudes that reduce the probability of thrombosis to show up.
In the specific case of covid, the first step is to avoid contact with the virus as much as possible. For this, the indication is to take the recommended doses of vaccine, wash your hands often and wear good quality masks in closed environments or in agglomeration.
“Overall, the recommendation is to have a healthy life”, summarizes Jardim.
The InCor pulmonologist explains that a physical exercise routine is essential so that the veins and arteries do not suffer from sudden blockages in blood flow.
“And you don’t necessarily need to go to the gym. The fact that you have a more active routine already greatly reduces the risk of having inadequate or improper clotting.”
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