“Clinical cardiovascular monitoring is essential in all subjects with a Covid-19 infection, even mild”, affirmed at the beginning of the week the Academy of Medicine, the body supposed to carry the consensus of the discipline in France.

The Covid and cardiovascular diseases maintain "dangerous links", she believes, based on several recent studies.

We already knew that cardiovascular patients have a higher risk of developing a more serious form of Covid.

This is in particular because the virus, Sars-Cov-2, attaches itself to a “receptor” – the enzyme ACE2 – particularly present in the cells of the blood vessels.

But what about cardiovascular effects in the general population?

And, if they are proven, can they intervene long after the infection?

The question ties into the wider uncertainties around long Covid, an enduring set of symptoms that are still poorly understood and poorly defined.

Examination of the heart rhythm of a patient who was infected with Covid-19, in France in April 2020 SEBASTIEN BOZON AFP / Archives

“Until now, (lasting) cardiovascular sequelae were reported only in hospitalized patients, in small series and with a short follow-up period,” notes the Academy.

But a large study, conducted in the United States and published in February in the journal Nature, changes, according to her, the situation.

Its results “predict a significant increase in cardiovascular disease worldwide” following the Covid pandemic.

150,000 veterans

Conducted among more than 150,000 US army veterans, all with Covid, this study measures the frequency of cardiovascular disorders in the year following infection.

She compares it to groups of veterans who have not been infected.

Result: "Beyond 30 days following infection, individuals with Covid-19 have a higher risk of cardiovascular disorders", concludes the study, citing infarctions, heart inflammation or strokes.

This risk "exists even in individuals who have not been hospitalized" because of the Covid, she notes, even if it remains much lower in these patients.

"Beyond 30 days following infection, individuals with Covid-19 have a higher risk of cardiovascular disorders", concludes the study JEAN-SEBASTIEN EVRARD AFP / Archives

This work has been praised by many researchers, in particular because it was carried out with a very large number of patients and over a long period.

However, experts are more skeptical.

It is "very difficult to draw relevant conclusions" from this study, British statistician James Doidge told AFP, finding too many methodological biases.

One of them is obvious: American veterans, as numerous as they are, are a very homogeneous population, as they are largely made up of rather old men.

It is therefore not necessarily representative, even if the authors of the study sought to correct these statistical biases.

This correction remains insufficient for Mr. Doidge who points to another problem: the study does not clearly distinguish the extent to which the disorders occur long after the infection.

Like the flu?

However, depending on whether they strike the patient just over a month after this, or almost a year later, the context will be different.

According to James Doidge, the study does not sufficiently differentiate "long-term complications from those associated with the acute phase of the disease".

However, this work "has the merit of existing", tempers French cardiologist Florian Zores to AFP.

The results of the study "predict a significant increase in cardiovascular disease worldwide" following the Covid pandemic Patrick T. FALLON AFP/Archives

He too notes several imperfections, but he believes that the study makes it possible to support hypotheses already deemed probable by many cardiologists with regard to the profile of Sars-Cov-2 which, like other viruses, can cause lasting inflammation.

However, "we have known for a long time that inflammation is a cardiovascular risk factor", notes Mr. Zores.

"In fact, we find exactly the same thing with the flu."

He thus recalls that in the 1920s, cardiovascular pathologies jumped in the wake of the Spanish flu pandemic.

Is there a specificity that would make the coronavirus even more dangerous in this respect?

Current studies do not make it possible to say this, and Florian Zores says he doubts "that there is a big difference" with the flu.

But the question does not necessarily change much in terms of public health.

From the moment this risk exists, the cardiologist considers it dangerous in any case to let the coronavirus circulate freely, given its high contagiousness.

© 2022 AFP