Risk of Recurrent Stroke Among PFO Patients Increases With Age

Among patients with patent foramen ovale (PFO) and history of stroke, older age is associated with a substantially higher risk of recurrent stroke, according to new epidemiologic research.

“This means that clinical research in this field has been ignoring the most numerous and high-risk patients for decades, excluding them from observational and interventional studies,” lead author Sara Mazzucco, MD, PhD (John Radcliffe Hospital, Oxford, England), told TCTMD in an email. “We can now give accurate prognostic information to our elderly patients with cryptogenic stroke and PFO. Their prognosis is not as benign as younger patients’; they probably need more aggressive treatment, and there is some evidence that they might benefit more from anticoagulation rather than antiplatelet treatment. It also means that we should not refrain from assessing thoroughly older stroke patients, including accurate cardiological evaluation.”

For the study, published online July 6, 2020, ahead of print in JAMA Neurology, Mazzucco and colleagues included 416 consecutive patients from the Oxford Vascular Study who were diagnosed with cryptogenic TIA or nondisabling stroke and screened for PFO between September 2014 and March 2019.

Among the 153 patients found to have PFO (mean age 66.7 years), the risk of recurrent stroke was similar to that of a pooled estimate from a systematic review of 23 other studies (2.05 vs 2.00 per 100 patient years). The heterogeneity between studies (P < 0.001), the researchers say, is “partly explained by the higher risk with increasing mean age of the study cohort,” with a P value of 0.003.

We don’t want history to repeat itself and again assume that results on young subjects will necessarily apply to older ones. Sara Mazzucco

Absolute risk increased by approximately 50% for every 10 years of increased patient age and the pooled ischemic stroke risk for patients 60 years and older was 3.27 per 100 patient-years.

“We knew that recurrent stroke is more frequent in older patients, just because the background risk factors are more prevalent,” Mazzucco told TCTMD. “However, not only did we show that older patients with cryptogenic stroke/TIA and PFO have significantly higher risk of recurrent stroke than younger patients—with a nearly threefold increase at the age of 70 or above as compared to the mean age of patients enrolled in closure trials—we also showed that this excess risk is specific, as it is only seen for older patients with PFO when compared to patients of the same age without PFO.”

The researchers say they would like to see their findings affect future research on PFO closure. Specifically, Mazzucco said called for trials to be more proactive in including older patients. “We don’t know whether in older patients PFO closure is as safe and effective as in younger ones,” she said. “We don’t want history to repeat itself and again assume that results on young subjects will necessarily apply to older ones.”

Also, she said researchers should do a better job of comparing PFO closure and medical management in older patients.

“Stroke is a pathology of older ages,” Mazzucco concluded. “We need to work to preserve and improve the well-being of older people as well as younger ones.”