Study: Endocarditis More Risky than Thought

Bacterial endocarditis increased the risk of stroke for these patients for a periiod of 4 months before and up to 5 months after the infection is diagnosed, a New York City research team reports.

Prior estimates were that the risk period spanned only 40 days before diagnosis and 5 weeks after that point.

Writing in the July 10 issue of Neurology, Alexander Merkler, MD, of NY-Presbyterian/Weill Cornell Medical Center and colleagues looked at a California administrative claims database.

Their retrospective, population-based study found nearly 18,000 cases of patients diagnosed and hospitalized with infective endocarditis between Jul 1, 2007 and June 30, 2011.

Of those, 2,275 patients had also had a stroke.

The risk was extremely high in the first month after diagnosis, when patients were nearly 90 times more likely to have a stroke than they were if they did not have endocarditis, Merkler wrote.

Most of the strokes (82.5%) were ischemic, followed by hemorrhagic (13.7%) or both diagnoses (3.8%).

Explaining the risk, the researchers wrote that “in some cases, strokes occurring before the diagnosis of infective endocarditis may be a manifestation of occult infection,,,,, particularly in the subacute form.” In other cases the infection “may reflect the presence of shared risk factors for both stroke and infective endocarditis,” such as cardiac valve surgery, post-stroke immunosuppression, or the use of central venous catheters after stroke.

They also suggest that there is a potential causal link between inflammation and stroke.

Infections “may contribute to inflammation and subsequently increase stroke risk,” Merkler wrote.