Correlation Between Beat-to-beat Blood Pressure Variability And Prognosis In Patients With Acute Ischemic Stroke

Background and Objective: Acute ischemic stroke(AIS)has become the first cause of death and disability among the population in China.Hypertension is one of the most important risk factors of stroke and affects the prevention,treatment and prognosis of stroke.Blood pressure variability(BPV)reflects the degree of fluctuation of blood pressure over time,which is one of the basic characteristics of blood pressure.Beat-to-beat BPV also known as very short term BPV,reflects the degree of change in blood pressure between each beat.Studies have shown that beat-to-beat BPV may be a stronger predictor of stroke recurrence than other types of BPV,but the characteristics of beat-to-beat BPV in patients with AIS and its relationship with stroke prognosis are unclear.Therefore,the aim of this study is to investigate the correlation between beat-to-beat BPV and prognosis in patients with AIS.Materials and Methods: The patients with AIS within 24 hours of onset at the stroke center of the First Hospital of Jilin University were prospectively and continuously enrolled from December 1st 2021 to December 1st 2022.When the patient was admitted to the hospital(within 24 hours of the onset of AIS),a non-invasive continuous blood pressure monitoring was performed,and each monitoring time was 5 minutes.For patients with AIS treated with reperfusion therapy,three additional beat-to-beat continuous blood pressure monitoring sessions were performed 24 hours after the end of treatment,and 3 and 7 days after treatment.Patients were followed up by telephone with modified Rankin Scale(m RS)score at 90 days after AIS.m RS score ≤1 was defined as good prognosis and m RS score >1 was defined as poor prognosis.The values of BPV included standard deviation(SD)and variation independent of mean(VIM).T-test,Mann-Whitney U test,and chi-square test were used for baseline demographic and related clinical characteristics.The correlation between beat-to-beat BPV indicators and clinical prognosis was analyzed by multifactorial logistic regression.Generalized estimating equation models were applied to compare the differences in different blood pressure variability indices between time points in patients receiving reperfusion therapy.Results: A total of 113 patients with AIS within 24 hours of onset,with a mean age of 61.56±10.23 years,were included in this study,containing 51 patients receiving reperfusion therapy,including 26 patients receiving intravenous thrombolysis and 25 patients receiving endovascular intervention.50 healthy subjects matched according to age and sex of patients with AIS were included as the control group.Compared with the control group,the beat-to-beat SD and VIM of systolic blood pressure and diastolic blood pressure in 24 hours of AIS onset were significantly higher in AIS patients with statistically significant differences(P<0.001).There were 69 patients in the good prognosis group(m RS ≤1)and 44 patients in the poor prognosis group(m RS >1).Compared with the good prognosis group,the beat-to-beat SD of systolic blood pressure [10.35(7.43,14.35)mm Hg vs.12.36(8.60,23.88)mm Hg,P=0.045] and beatto-beat VIM of systolic blood pressure [10.27(7.47,14.69)mm Hg vs.12.25(8.26,23.95)mm Hg,P=0.043] in poor prognosis group were significantly higher,while beatto-beat SD of diastolic blood [7.74(4.60,9.80)mm Hg vs.8.73(4.89,13.46)mm Hg,P=0.109] and beat-to-beat VIM of diastolic blood [7.59(4.35,10.71)mm Hg vs.8.64(4.86,13.35)mm Hg,P=0.099] in poor prognosis group showed no statistical difference.After controlling other confounding factors,beat-to-beat SD and VIM of systolic blood pressure in 24 hours of AIS onset were independently associated with poor prognosis in patients with AIS(adjusted OR=1.176,95%CI: 1.053-1.313,P=0.004;adjusted OR=1.172,95%CI: 1.053-1.306,P=0.004).In addition,the results of the generalized estimating equations showed statistically significant beat-to-beat SD and VIM for systolic and diastolic blood pressure at different time points in terms of time effects(P=0.026,0.016,0.014,0.009,respectively).There were not statistically significant in terms of interaction effects(P=0.891,0.831,0.901,0.835,respectively)and between-group effects for therapy(P=0.183,0.062,0.167,0.061,respectively).Independent of type of treatment,beat-to-beat SD and VIM of systolic and diastolic blood pressures in patients receiving reperfusion therapy decreased progressively with time point to a minimum by day 7 of onset.Conclusions: The beat-to-beat BPV in 24 hours of onset in patients with AIS,especially the patients receiving endovascular intervention,was independently associated with poor prognosis at three months.The beat-to-beat BPV in patients with AIS may be a target for intervention to improve clinical prognosis.