A recent comprehensive study indicates that Covid-19 may significantly increase the risk of experiencing heart attacks and strokes for up to three years post-infection. The research, published in the prestigious medical journal Atherosclerosis, Thrombosis, and Vascular Biology, utilized medical records from nearly 250,000 individuals enrolled in the extensive UK Biobank database. Among these records, over 11,000 individuals had a confirmed Covid-19 diagnosis in 2020, with nearly 3,000 of them requiring hospitalization due to the severity of their condition. These groups were then compared against a control group of more than 222,000 individuals within the same database who had no history of Covid-19 during the same period.

The findings revealed that those who contracted Covid-19 in 2020, prior to the widespread availability of vaccines, had a twofold increased risk of a major cardiac event, such as a heart attack or stroke, or death, for almost three years following their illness. This risk was even more pronounced for individuals who had been hospitalized, with their risk being over three times higher than those without a Covid-19 diagnosis. Intriguingly, for those hospitalized, Covid-19 was found to be as potent a risk factor for future cardiovascular events as conditions like diabetes or peripheral artery disease.

It is estimated that over 3.5 million Americans were hospitalized due to Covid-19 between May 2020 and April 2021. The study observed no reduction in the elevated cardiac risks associated with the infection over time, a finding that was described by study author Dr. Stanley Hazen, who heads the department of Cardiovascular & Metabolic Sciences at the Cleveland Clinic, as "one of the more interesting and surprising findings."

Dr. Patricia Best, a cardiologist at the Mayo Clinic in Rochester, Minnesota, and not involved in the study, noted the uniqueness of this prolonged effect, stating, "We have long understood that infections can temporarily elevate the risk of heart attacks, but this risk typically subsides shortly after the infection clears. The substantial and enduring impact of Covid-19 on cardiovascular health is likely due to the distinct nature of the virus compared to other infections."

The precise mechanisms behind Covid-19's long-lasting effects on the cardiovascular system remain unclear. However, previous research has shown that the coronavirus can infect the cells lining blood vessel walls and has been detected in arterial plaques, which, if they rupture, can lead to heart attacks and strokes. Dr. Hooman Allayee, a professor of biochemistry and molecular genetics at the Keck School of Medicine at the University of Southern California and a study author, suggested that "Covid may cause sustained damage to the arterial walls and vascular system, leading to ongoing manifestations over time."

Allayee and his graduate student James Hilser further investigated whether individuals with known genetic predispositions to heart disease or gene variations associated with Covid-19 susceptibility were more likely to suffer heart attacks, strokes, or death after hospitalization for Covid-19. However, no such correlation was found. Instead, a distinction based on blood type emerged. It is known that individuals with non-O blood types (A, B, or AB) are at a higher risk of cardiovascular diseases, and this study suggests that blood type may also influence Covid-19 susceptibility and outcomes. Interestingly, the study found that individuals with O-type blood who were hospitalized for Covid-19 had a slightly lower risk of heart attack or stroke compared to those with A, B, or AB blood types, although they were still at an elevated risk.

The researchers hypothesize that the gene responsible for blood type may play a role in the increased risk of heart attacks and strokes following Covid-19 infection, although the exact nature of this relationship is yet to be determined. On a more optimistic note, the study also found that individuals hospitalized for Covid-19 who were taking low-dose aspirin did not experience an increased likelihood of subsequent heart attacks or strokes. This suggests that the risk can be mitigated, according to Dr. Hazen.

"Cardiovascular diseases remain the leading cause of death globally," Dr. Hazen emphasized. He now routinely inquires about patients' Covid-19 history, stating, "For those who have had Covid-19, it is crucial that we are vigilant in reducing their cardiovascular risk through measures such as controlling blood pressure and cholesterol levels and possibly taking daily aspirin."

The study did not examine the impact of Covid-19 vaccination on cardiovascular risk, but Dr. Hazen speculates that vaccinations are likely protective, as they generally prevent severe Covid-19 infections. The study also did not explore whether multiple Covid-19 infections could lead to even greater health risks, a possibility suggested by some research. Nevertheless, Dr. Hazen advises that anyone hospitalized for Covid-19, regardless of vaccination status, should be mindful of their heart health risks.