The study compared the Reveal Linq insertable cardiac monitor (ICM) to patients randomized to standard of care. Those patients did not receive continuous long-term monitoring. Medtronic presented the three-year data at the American Stroke Association’s International Stroke Conference (ISC) 2023.
According to a news release, it builds on the 12-month Stroke AF study data published in JAMA in June 2021. The data includes about a 10-fold increase in AFib detection with the Reveal Linq technology.
Reveal Linq detected AFib in 12.5% of patients compared to 1.8% of patients randomized to standard of care. The standard of care techniques included 12-lead ECGs, Holter monitoring, telemetry or event recorders. At three years, the rate of AFib detection increased to 21.7% in the ICM arm. That compared to 2.4% of patients in the control group.
Medtronic said the study also demonstrated that 67% of patients (31 out of 46) in the ICM arm had clinically relevant AFib episodes lasting more than one hour in duration. Meanwhile, 88% of AFib episodes proved asymptomatic.
The company said it didn’t design the Stroke AF study to detect or explain treatment differences. However, 70% of patients with AFib detected in the ICM arm subsequently started anticoagulation therapy to help prevent blood clots. Patients with AFib are at a five-fold increased risk for ischemic stroke, Medtronic said.
What the Medtronic Reveal Linq data means
Dr. Lee Schwamm, chief digital advisor at Mass General Brigham, said the data demonstrated the unreliability of patient-reported symptoms because the AFib detected in the study was asymptomatic. Schwamm, who also serves as C. Miller Fisher endowed chair in vascular neurology and professor of Neurology at Massachusetts General Hospital and Harvard Medical School, said “we can’t always rely on patients to tell us they are having palpitations or irregular heartbeats.”
“Importantly, these outcomes underscore the criticality of long-term monitoring with ICMs in these patients as much of the AF detected would have been missed at 30 days,” he said. “AF is a risk that we can’t afford to miss for patients who have already suffered a stroke — the consequences could be devastating.”
One-year outcomes from the study add insights for predicting AFib in patients with small or large vessel ischemic strokes. Patients with congestive heart failure or left atrial enlargement may have a greater risk of AFib, Medtronic said. They had AFib detection rates of 23.4% compared to 5% for patients with neither attribute.
“The Stroke AF Predictors analysis helps us better identify the patients who are most at-risk of unsuspected AF, which can inform stroke prevention strategies,” said Schwamm. “Not every ischemic stroke patient may need an ICM, but these data suggest some patients are more likely to experience AF and should be monitored more closely.”
Stroke AF, a prospective, randomized study, evaluates 496 large and small vessel stroke patients. It functions across 33 centers in the U.S.
Reveal Linq received FDA clearance in 2014. Medtronic offers the system worldwide.