It was clear very early on in the pandemic that Sars-CoV-2 can damage the heart and blood vessels of those infected. Patients developed clots, heart inflammation, abnormal heart rhythms, and heart failure.
Now, the first major study of long-term cardiovascular consequences of infection shows that the effects of the virus are often permanent. In an analysis of more than 11 million US veterans’ health records, the researchers found that the risk of 20 different cardiovascular diseases was significantly higher in veterans who had contracted Covid-19 a year earlier than in those who were not ill. Risks increased significantly with the severity of the original condition and included all the problems studied, such as heart attacks, arrhythmias, strokes and cardiac arrest. But even people who never went to the hospital had more cardiovascular disease than those who were never infected.
The results are “definitely worse than I expected,” says Eric Topol, a cardiologist at the Scripps Research Institute in San Diego. “If anyone ever thought Covid was like the flu, this should be one of the most powerful pieces of data to show it’s not.” He adds that the new study “is perhaps the most impressive study on Long Covid that we’ve seen to date.”
Other experts also agree that the Results of the in Nature Medicine published study are very telling: “In the post-Covid era, Covid could become the biggest risk factor for cardiovascular consequences” – greater even than well-documented risks such as smoking and obesity, says Larisa Tereshchenko, a cardiologist and biostatistician at the Cleveland Clinic. However, she warns that this is a retrospective study that must now be repeated with additional data. In addition, prospective studies are needed to accurately assess the risks.
It is also unclear exactly how the virus causes this long-term damage. One suggestion is that cardiovascular disease and a range of symptoms, such as fatigue and loss of smell, may have common roots. The study provides “clear evidence of long-term damage to the heart and vessels. Something similar could also happen in the brain and other organs, leading to the symptoms characteristic of Long Covid,” says lead author Ziyad Al-Aly, clinical epidemiologist from Washington University in St. Louis. In a parallel published study his team found an increased risk of neuropsychiatric problems in subjects about a year after the corona infection.
These findings are consistent with numerous other studies on long-term damage after a Covid infection. However: For most studies on the long-term consequences of Covid-19, the patients were only followed for a few months; control groups were often absent.
If the corona infection is severe, the risk of other diseases is greater later
For the current study, the team used the largest data set to date maintained by the US Department of Veterans Affairs (VA). The scientists analyzed the data of almost 154,000 people who were infected with Sars-CoV-2 between March 1, 2020 and January 15, 2021 and were still alive at least 30 days after infection. They identified two control groups: 5.6 million people who contacted the VA during the pandemic but were not diagnosed with Covid-19 – and 5.9 million people who contacted the VA in 2017.
The authors also analyzed data from the phase of the pandemic when vaccines were not yet widely available: 99.7 percent of veterans were not vaccinated when they got Covid-19. In addition, the study’s demographic composition was skewed: About 90 percent of the participants were males and 71 to 76 percent were white. The patients were on average in their early 60s.
The researchers considered the possibility that the people infected with Sars-CoV-2 were already at higher risk of cardiovascular disease. “Covid is an opportunist,” says Al-Aly. “We found an increased risk of cardiovascular problems in old and young people, in diabetics and non-diabetics, in obese and non-obese people, in smokers and non-smokers.”
Covid-19 increased the risk of all of the 20 cardiovascular diseases studied, including heart attacks, cardiac arrhythmias, strokes, heart failure, cardiac arrest, pulmonary embolism and deep vein thrombosis. For example, after 12 months, infected veterans had a 72 percent higher risk of heart failure than their peers who had not tested positive. This means that almost twelve more infected people per 1000 people developed heart failure than controls. Overall, the infection increased the risk of contracting one of the 20 diseases by 63 percent compared to the controls from the pandemic period.
Miriam Merad, an immunologist at the Icahn School of Medicine at Mount Sinai, also notes that the researchers found “a clear correlation between the severity of the symptoms and the severity of the original disease”. The long-term risks increased significantly from outpatients to hospital patients to patients in the intensive care unit.
The virus may attack the endothelial cells in the heart
The team used statistical correction methods in order to be able to take into account the small number of women and people of color examined in the evaluation. The findings are likely relevant to these people as well, says Elizabeth Ofili, a cardiologist at the Morehouse School of Medicine.
One possible mechanism for long-term damage is inflammation of the endothelial cells that line the heart and blood vessels, says Al-Aly. So it is known that the virus attacks these cells directly. But the researchers also cite a number of other potential mechanisms, including an increased tendency for blood to clot and increased levels of pro-inflammatory chemical messengers called cytokines. “The suspected mechanisms are still in the realm of speculation,” says Al-Aly.
According to the authors, their findings suggest that millions of Covid-19 survivors could suffer long-term consequences that burden healthcare for years to come. “Governments and health systems around the world should be prepared for the likely significant contribution of the Covid-19 pandemic to increasing the burden of cardiovascular disease,” they write.
“Some of these diseases are chronic and will literally affect people for life,” adds Al-Aly. “It’s not like you wake up tomorrow and suddenly you don’t have heart failure anymore.”
This post is in the original in the science magazine Science published, published by the AAAS. German editing: cvei