Undetermined stroke with an embolic pattern—a common phenotype with high early recurrence risk

Abstract

Introduction. Undetermined strokes with an embolic pattern (USEP) represent a common phenotype. We assessed their frequency and compared USEP with cardioembolic stroke with a known source and non-cardioembolic stroke etiology.

Methods. Study patients were 540 consecutive ischemic stroke patients admitted to Helsinki University Hospital with primary end-point of recurrent stroke in a 21-month follow-up. Cox regression adjusting for CHA₂DS₂-VASc and anticoagulation estimated the risk of USEP on recurrent stroke.

Results. A total of 229 (42.4%) patients had a non-cardioembolic stroke etiology, 184 (34.1%) had a cardioembolic stroke with a known source, and 127 (23.5%) were classified as USEP. USEP patients had less diabetes and prior TIA, with more severe symptoms than the non-cardioembolic stroke cases. They were younger, had fewer comorbidities, and less severe symptoms than the cardioembolic stroke patients. Cumulative risk of recurrent stroke was 10.0% (95% CI 4.1%–15.9%) for USEP, 5.0% (1.1%–8.9%) for cardioembolic strokes, and 5.0% (3.0%–7.0%) for non- cardioembolic strokes (P = 0.089). USEP associated with a higher risk of recurrent stroke compared to non-cardioembolic strokes (hazard ratio 2.36, 95% CI 1.02–5.47; P = 0.046) and cardioembolic stroke with a known source (1.83, 1.07–3.14; P = 0.028).

Conclusions. Despite their younger age and more favorable risk factor profile compared with other phenotypes, USEP exhibited a high risk of stroke recurrence.

Key words: :

• Atrial fibrillation
• mortality
• recurrence
• stroke

Funding: Helsinki University Hospital research funds (Grant No. TYH2014407).

Declaration of interest: J.P.: Research grant for related research: Finnish Medical Foundation, Helsinki University Hospital; honoraria for consultancy: Boehringer-Ingelheim, BMS-Pfizer, Medtronic; honoraria for lectures: Boehringer-Ingelheim, BMS-Pfizer, Orion Pharma, Bayer.

T.N.: Honoraria for consultancy: Boehringer-Ingelheim; honoraria for lectures: Boehringer-Ingelheim, Orion Pharma, Medtronic.

A.M.: Research grant for related research: Finnish Medical Foundation, Academy of Finland, National Health and Medical Research Council; honoraria for travel costs for a talk at the World Stroke Congress 2014; Siemens.

K.R.: Honoraria for lectures: Boehringer-Ingelheim.

M.L.: Honoraria for consultancy: Boehringer-Ingelheim, BMS-Pfizer, Bayer; honoraria for lectures: Boehringer-Ingelheim, BMS-Pfizer, Bayer.

T.T.: Scientific advisory board membership for Boehringer-Ingelheim, Bayer, and Pfizer; consultant to Boehringer-Ingelheim, Bayer, and Pfizer; research contracts with Boehringer-Ingelheim, Bayer, and Pfizer; speaker's honorarium from Boehringer-Ingelheim, Bayer, and Pfizer.

E.H., J.K., D.S., S.C., S.P. , N.H., S.M.: None.

Supplementary material available online

Supplementary Table I to be found online at http://informahealthcare.com/doi/abs/10.3109/07853890.2015.1057612.

Supplementary Figure 1 to be found online at http://informahealthcare.com/doi/abs/10.3109/07853890.2015.1057612.