The combination of heart rate variability and ABCD 2 score portends adverse outcomes after minor stroke or transient ischemic attack.

BACKGROUND AND PURPOSE: The residual recurrent risk of stroke, which cannot be entirely explained by the traditional ABCD2 score, still existed. Heart rate variability (HRV), a method for reflecting the function of automatic nervous system (ANS), was a novel predictor of secondary stroke events. We aimed to investigate the relationships of combined HRV and ABCD2 score with adverse outcomes after acute minor stroke (MS) or transient ischemic attack (TIA), and further investigate the independent associations between HRV and adverse outcomes after MS/TIA stratified by ABCD2 score.

METHODS: Data were obtained from the Third China National Stroke Registry (CNSR-III) study. We assessed the activity of ANS using standard deviation of NN intervals (SDNN), a time domain index of HRV. Trained investigators collected clinical characteristics and estimated ABCD2 score for each participant. All enrolled patients were categorized into different risk groups based on SDNN level and ABCD2 score. The clinial outcomes included recurrent stroke, recurrent ischemic stroke, and disability within 1-year follow-up. We evaluated whether combined SDNN and ABCD2 score were associated with recurrent events using multivariable Cox regression models, and those with disability using multivariable logistic regression models. The independent associations between SDNN and diverse outcomes stratified by ABCD2 score were explored using multivariable Cox and logistic regression analyses.

RESULTS: A total of 5,743 participants [3,316 (70.02) males, 62.0 (54.0-69.0) years] were included. Patients with low SDNN and ABCD2  ≥ 4 were associated with higher risk of recurrent stroke within 1 year (10.8% versus 4.9%; [HR] 1.31, 95% [CI] 0.92-1.88, P = 0.14) compared to patients with high SDNN with ABCD2 < 4. Lower SDNN was associated with higher recurrent stroke in patients with ABCD2 0-3 score ([HR] 0.73, 95% [CI] 0.57-0.947, P = 0.01) and ABCD2 4-5 score ([HR] 0.85, 95% [CI] 0.74-0.97, P = 0.02), but not in patients with ABCD2 6-7 score.

CONCLUSION: The combination of HRV and ABCD2 score might efficiently stratify the risk of 1-year recurrent stroke after MS/TIA. Moreover, lower SDNN was independently related to recurrent stroke in patients with MS/TIA, especially for those with low-to-moderate traditional vascular risk factors.