Health Rounds: RSV infection raises heart risk in unvaccinated adults

Hello Health Rounds Readers! Today we have a pair of studies that look at the adverse effects a disease or certain medications can have on the heart - in these cases, RSV infection and cancer drugs known as anthracyclines.

RSV in unvaccinated adults raises heart risks

Cardiac events are common among older unvaccinated adults who are hospitalized with respiratory syncytial virus (RSV) infection, according to a new study.

Among 6,248 unvaccinated U.S. adults aged 50 or older who were hospitalized with RSV, more than one in five experienced an acute cardiac event, researchers reported on Monday in JAMA Internal Medicine.

Those who experienced one of these events had a 54% higher risk of needing intensive care, and a 77% higher risk of dying in the hospital, compared to patients who did not.

The most common adverse cardiac event was heart failure, occurring in 16%. Also documented were acute blockages of the arteries carrying blood to the heart, high blood pressure crises, life-threatening heart rhythm problems, and shock.

These complications occurred in roughly one in three patients with a history of heart problems and in nearly one in 10 with no previous diagnosis of cardiovascular disease.

An editorial published with the report points out that two recently-approved vaccines from Pfizer PFE and GSK GSK are effective in preventing severe RSV infections in adults 60 years or older, and preliminary data suggest they are also safe and effective in younger adults.

“Many clinicians and patients are still unaware of RSV burden of disease and prognosis in older adults,” the editorial notes, adding that in the U.S. the vaccines “are inconsistently covered by insurers” for patients not enrolled in Medicare.

“Vaccine fatigue and access barriers among currently eligible persons need to be addressed to enhance uptake by those who stand to benefit,” the editorial said.

Heart failure from cancer drugs may be preventable

Newly discovered clues to how some common cancer drugs cause heart failure may open the way to treatments that let patients keep taking the drugs while preventing the damage, researchers said.

Millions of cancer patients take a class of chemotherapy medicines known as anthracyclines, but a third of them develop some degree of irreversible cardiac injury. In more than 5%, that injury leads to chronic heart failure, the researchers explained in a report published on Tuesday in JACC CardioOncology.

How these drugs induce their damage has been a mystery, until now. It turns out that injury to heart cells’ mitochondria - their “energy factories” - is the main driver of the damage, the researchers discovered.

“The heart beats without interruption throughout life and has one of the most intense energy requirements of any organ in the body," study coauthor Dr. Borja Ibanez of the Centro Nacional de Investigaciones Cardiovasculares (CNIC) in Madrid said in a statement.

"Any failure in the energy production chain has major consequences,” he said.

The researchers found that these anthracyclines alter cardiac metabolism, causing a change in the supply of these fuels and an irreversible dysfunction in energy production by mitochondria.

The metabolic changes begin soon after the start of anthracycline treatment, long before the heart begins to lose its pumping strength, the researchers also found.

“As a consequence of these metabolic alterations, the heart begins to atrophy (its cells lose volume) in one of the first signs of irreversible damage,” said coauthor Anabel Diaz-Guerra, also of the CNIC.

One possible intervention involves a specific dietary adjustment. The team is conducting a study in animals to test the ability of a protein-enriched diet to prevent muscle atrophy, including cardiac muscle atrophy, induced by anthracycline chemotherapy.

“If the encouraging preliminary results are confirmed this will be pursued in a clinical trial,” said Dr. Ibanez.