Research

CSANZ 2021: Novel biomarker may help solve the cryptogenic stroke puzzle


Left atrial strain can help predict recurrent ischaemic stroke or TIA in patients with cryptogenic stroke.

Speaking at Cardiac Society of Australia and NZ 2021 meeting, Dr Aditya Bhatt said the biomarker would help identify those patients with cryptogenic stroke with a possible cardioembolic mechanism of stroke development who would most benefit from anticoagulation.

It would also identify the patients with cryptogenic stroke who would most benefit from prolonged heart rhythm monitoring given the known association between atrial cardiopathy and AF.

Dr Bhatt, a cardiologist and research fellow at Blacktown Hospital and a Ralph Reader Clinical Prize finalist, said atrial cardiopathy has been shown to be a causative factor in thrombosis, independent of atrial fibrillation.

Early left atrial remodelling can be detected with echocardiographic strain before mechanical dysfunction and chamber dilatation develops.

The prospective observational study comprised 709 adults with ischaemic stroke or TIA enrolled over a four-year period 2016-2020.

All underwent full transthoracic echocardiography during admission as well as CT/MRI imaging of the brain, vascular imaging of the aorta, carotids and intracranial vessels, ECG and 24 hr telemetry monitoring, and fasting lipids and sugar profiles.

The study found high rates of comorbidities such as diabetes (40%), hypertension (69%), obesity (33%) and active smoking (27%), consistent with findings from other large stroke registries.

Patients were segmented to three stroke subtypes either cryptogenic (41%), cardioembolic (32%), or non-cardioembolic (27%) which included strokes from small vessel occlusion, large artery atherosclerosis and other causes.

Dr Bhjatt said left atrial reservoir and contractile strain were significant discriminators of cardioembolic stroke.

“A threshold of 23% for left atrial reservoir strain and 13% for contractile strain showed good sensitivity and specificity for identifying cardioembolism.”

The study found 12.6% of the cryptogenic stroke cohort developed the primary outcome of recurrent ischaemic stroke of TIA over a mean period of 20 months follow-up.

Reduced LA reservoir and contractile strain, below the thresholds for cardioembolic stroke, predicted recurrent stroke /TIA in the cryptogenic stroke group (RR 2.88 and 2.17 respectively).

“LA strain provides independent predictive value above traditional echocardiographic and clinical risk factors for prediction of recurrent ischaemic stroke/TIA in patients with cryptogenic stroke,” he concluded.

He said the study had identified a biomarker which can be used in patients with cryptogenic stroke to identify those at high risk of stroke recurrence.

“We postulate that the atrial cardiopathy identified here plays a large role in the cryptogenic stroke puzzle.”

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