The association between aortic valve replacements (AVR) and clinical strokes may be stronger than originally believed, data from a study published April 1 in Circulation suggest.

In the Determining Neurologic Outcomes from Valve Operations (DeNOVO) study, Steven R. Messé, MD, of the Hospital of the University of Pennsylvania in Philadelphia, and co-investigators assessed data from 196 participants aged 65 and older who underwent AVR for calcific moderate-to-severe aortic stenosis at two hospitals within the University of Pennsylvania Health System. Neurologists evaluated patients before and after surgery, and the patients underwent MR imaging (MRI) after surgery. Pre-operative and post-operative evaluations included examinations using a National Institutes of Health Stroke Scale (NIHSS).

Clinical strokes occurred in 17 percent of participants, transient ischemic attack (TIA) occurred in 2 percent and in-hospital mortality occurred in 5 percent. The frequency of stroke in the study cohort was higher than the frequency reported in the Society of Thoracic Surgery database.

Most strokes were mild, with an average NIHSS score of 3. There was also an association between clinical stroke and increased length of stay (average of 12 days vs. 10 days). There was a strong association between a moderate or severe stroke (NIHSS score of 10 or greater) and in-hospital mortality (38 percent vs. 4 percent).

Among the 109 participants who did not have strokes, 59 experienced a silent infarct. However, silent infarct was not associated with in-hospital mortality or increased length of stay.

The authors noted that they are still following participants in order to help determine the long-term outcomes of clinical and subclinical injury.