Original Article
Low blood pressure during the acute period of ischemic stroke is associated with decreased survival Peter Wohlfahrt a,b,c, Alena Krajcoviechova a, Marie Jozifova a, Otto Mayer d, Jiri Vanek d, Jan Filipovsky d, and Renata Cifkova a,b,e
Objectives: There is no agreement on optimal blood pressure (BP) level during the acute phase of stroke, because studies on the relation between BP and stroke outcome have shown contradicting results. The aim of this study was to compare the relationship of admission, maximal, discharge BP and its components during hospitalization for the first-ever acute ischemic stroke with total mortality after stroke. Methods: In 532 consecutive patients (mean age 66 10 years, 59% of men) hospitalized for their first-ever ischemic stroke, the association between BP and total mortality during a median follow-up of 66 weeks (interquartile range 33–119 weeks) was analyzed. Results: In multivariate analysis, both admission mean BP (MBP) and discharge SBP quartiles were independent predictors of mortality and outperformed other parameters of BP. After multivariate adjustments, patients with admission MBP below 100 mmHg had a higher risk of death than those with MBP between 100–110 and 110–121 mmHg, whereas the risk of mortality did not differ from the group with admission MBP above 122 mmHg. Similarly, patients with discharge SBP below 120 mmHg had an increased risk of death as compared to groups with SBP between 120–130 and 130–141 mmHg, whereas the risk of death was similar to that with discharge SBP above 141 mmHg. Conclusion: Among patients hospitalized for their firstever ischemic stroke, the risk of all-cause death is significantly increased in those with admission MBP below 100 mmHg and discharge SBP below 120 mmHg, even after adjustments for other confounders.
BP-lowering in preventing the first ischemic stroke are well established [1,2]. In the secondary prevention after stroke, a higher BP increases the risk of recurrent stroke, whereas antihypertensive therapy reduces the risk of stroke [3]. In contrast, there is limited evidence from randomized controlled trials to guide the management of BP during the acute phase of stroke. Similarly, there is no agreement on optimal BP level during the acute phase of stroke. While most patients with acute ischemic stroke have increased BP, it usually settles without intervention during the first week after hospitalization [4]. High BP in the acute phase may be beneficial to maintain blood flow in the ischemic penumbra [5], in which cerebral autoregulation is disrupted and cerebral perfusion is dependent on systemic BP [6], whereas other studies have shown no impairment of global or regional cerebral blood flow after BP reduction [7–9]. Furthermore, high BP may be detrimental by inducing brain edema and hemorrhagic transformation. Although a number of studies have assessed the relationship between BP in the acute phase of ischemic stroke and clinical outcomes, the results are conflicting. Similarly, the predictive value of different components of BP and the admission, maximal, and discharge BP have not been thoroughly compared. The purpose of this study was to compare the relationship between admission, maximal, and discharge BP and its components during hospitalization for the first acute ischemic stroke and total mortality after stroke.
METHODS Study population All consecutive patients aged less than 81 years and hospitalized at Thomayer Hospital, Prague and University
Keywords: blood pressure, ischemic stroke, mortality, outcome Abbreviations: BP, blood pressure; CCS, Causative Classification of Stroke System; IQR, interquartile range; MBP, mean blood pressure; NIHSS, National Institute of Health Stroke Scale; PP, pulse pressure
INTRODUCTION
H
ypertension is a well recognized risk factor for ischemic stroke. In the primary prevention of stroke, the relationship between blood pressure (BP) and the risk of ischemic stroke, and the effect of Journal of Hypertension
Journal of Hypertension 2015, 33:339–345 a Center for Cardiovascular Prevention of the First Faculty of Medicine, Charles, University and Thomayer Hospital, Prague, bInternational Clinical Research Center, St Ann’s University Hospital, Brno, cDepartment of Preventive Cardiology, Institute for Clinical and Experimental, Medicine, Prague, d2nd Department of Internal Medicine, Charles University, Center for Hypertension, Pilsen and eDepartment of Cardiology and Angiology, First Faculty of Medicine, Charles, University, Prague, Czech Republic
Correspondence to Peter Wohlfahrt, MD, PhD, Center for Cardiovascular Prevention of the First Faculty of Medicine, Charles University and Thomayer Hospital, Videnska 800, 140 59 Prague 4, Czech Republic. Tel: +420 261 083 694; fax: +420 261 083 821; e-mail: [email protected] Received 26 June 2014 Revised 8 September 2014 Accepted 8 September 2014 J Hypertens 33:339–345 Copyright ß 2015 Wolters Kluwer Health, Inc. All rights reserved. DOI:10.1097/HJH.0000000000000414
www.jhypertension.com
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
339
Hospital, Pilsen, Czech Republic for their first-ever ischemic stroke between March 2009 and January 2012 were eligible for this survey. Neurological symptoms had to last for more than 24 h (consistent with the original WHO criteria [10]) unless thrombolytic therapy was applied. Only patients with computed tomography (CT) or MRI excluding hemorrhagic stroke were enrolled into the study. Patient characteristics on hospital admission/during hospitalization for acute stroke were retrospectively retrieved from their medical records. All eligible patients with complete data on admission and discharge BP (except for patients with missing discharge BP due to in-hospital death) were included in the analysis. The subtype of acute ischemic stroke was classified using a validated computerized algorithm for causative classification of ischemic stroke [Causative Classification of Stroke System (CCS)] [11] by two independent blinded physicians certified in CCS classification. Disagreements on stroke cause classification were discussed. The neurological severity on admission was assessed using the National Institute of Health Stroke Scale (NIHSS) score. Hypertension was defined as a history of hypertension or use of antihypertensive drugs. Diabetes was defined as a history of diabetes or antidiabetic treatment. Dyslipidemia was defined as a history of dyslipidemia or use of lipid-lowering drugs. The study was approved by the joint local Ethics Committee of the Institute for Clinical and Experimental Medicine and Thomayer Hospital, Prague, Czech Republic. All participants provided their informed written consent.
Blood pressure measurement SBP and DBP values on hospital admission, maximal BP during hospitalization, and BP at discharge were retrieved from medical records. Pulse pressure (PP) was calculated as the difference between SBP and DBP. Mean blood pressure (MBP) was calculated as MBP ¼ DBP þ [(SBP DBP)/3].
Clinical outcome The outcome in the present study is total mortality, which was assessed from the General Health Insurance Company registry that keeps, by law, a list of all people insured and deceased. The median follow-up was 66 weeks [interquartile range (IQR) 33–119 weeks].
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Low blood pressure during the acute period of ischemic stroke is associated with decreased survival Peter Wohlfahrt a,b,c, Alena Krajcoviechova a, Marie Jozifova a, Otto Mayer d, Jiri Vanek d, Jan Filipovsky d, and Renata Cifkova a,b,e
Objectives: There is no agreement on optimal blood pressure (BP) level during the acute phase of stroke, because studies on the relation between BP and stroke outcome have shown contradicting results. The aim of this study was to compare the relationship of admission, maximal, discharge BP and its components during hospitalization for the first-ever acute ischemic stroke with total mortality after stroke. Methods: In 532 consecutive patients (mean age 66 10 years, 59% of men) hospitalized for their first-ever ischemic stroke, the association between BP and total mortality during a median follow-up of 66 weeks (interquartile range 33–119 weeks) was analyzed. Results: In multivariate analysis, both admission mean BP (MBP) and discharge SBP quartiles were independent predictors of mortality and outperformed other parameters of BP. After multivariate adjustments, patients with admission MBP below 100 mmHg had a higher risk of death than those with MBP between 100–110 and 110–121 mmHg, whereas the risk of mortality did not differ from the group with admission MBP above 122 mmHg. Similarly, patients with discharge SBP below 120 mmHg had an increased risk of death as compared to groups with SBP between 120–130 and 130–141 mmHg, whereas the risk of death was similar to that with discharge SBP above 141 mmHg. Conclusion: Among patients hospitalized for their firstever ischemic stroke, the risk of all-cause death is significantly increased in those with admission MBP below 100 mmHg and discharge SBP below 120 mmHg, even after adjustments for other confounders.
BP-lowering in preventing the first ischemic stroke are well established [1,2]. In the secondary prevention after stroke, a higher BP increases the risk of recurrent stroke, whereas antihypertensive therapy reduces the risk of stroke [3]. In contrast, there is limited evidence from randomized controlled trials to guide the management of BP during the acute phase of stroke. Similarly, there is no agreement on optimal BP level during the acute phase of stroke. While most patients with acute ischemic stroke have increased BP, it usually settles without intervention during the first week after hospitalization [4]. High BP in the acute phase may be beneficial to maintain blood flow in the ischemic penumbra [5], in which cerebral autoregulation is disrupted and cerebral perfusion is dependent on systemic BP [6], whereas other studies have shown no impairment of global or regional cerebral blood flow after BP reduction [7–9]. Furthermore, high BP may be detrimental by inducing brain edema and hemorrhagic transformation. Although a number of studies have assessed the relationship between BP in the acute phase of ischemic stroke and clinical outcomes, the results are conflicting. Similarly, the predictive value of different components of BP and the admission, maximal, and discharge BP have not been thoroughly compared. The purpose of this study was to compare the relationship between admission, maximal, and discharge BP and its components during hospitalization for the first acute ischemic stroke and total mortality after stroke.
METHODS Study population All consecutive patients aged less than 81 years and hospitalized at Thomayer Hospital, Prague and University
Keywords: blood pressure, ischemic stroke, mortality, outcome Abbreviations: BP, blood pressure; CCS, Causative Classification of Stroke System; IQR, interquartile range; MBP, mean blood pressure; NIHSS, National Institute of Health Stroke Scale; PP, pulse pressure
INTRODUCTION
H
ypertension is a well recognized risk factor for ischemic stroke. In the primary prevention of stroke, the relationship between blood pressure (BP) and the risk of ischemic stroke, and the effect of Journal of Hypertension
Journal of Hypertension 2015, 33:339–345 a Center for Cardiovascular Prevention of the First Faculty of Medicine, Charles, University and Thomayer Hospital, Prague, bInternational Clinical Research Center, St Ann’s University Hospital, Brno, cDepartment of Preventive Cardiology, Institute for Clinical and Experimental, Medicine, Prague, d2nd Department of Internal Medicine, Charles University, Center for Hypertension, Pilsen and eDepartment of Cardiology and Angiology, First Faculty of Medicine, Charles, University, Prague, Czech Republic
Correspondence to Peter Wohlfahrt, MD, PhD, Center for Cardiovascular Prevention of the First Faculty of Medicine, Charles University and Thomayer Hospital, Videnska 800, 140 59 Prague 4, Czech Republic. Tel: +420 261 083 694; fax: +420 261 083 821; e-mail: [email protected] Received 26 June 2014 Revised 8 September 2014 Accepted 8 September 2014 J Hypertens 33:339–345 Copyright ß 2015 Wolters Kluwer Health, Inc. All rights reserved. DOI:10.1097/HJH.0000000000000414
www.jhypertension.com
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
339
Hospital, Pilsen, Czech Republic for their first-ever ischemic stroke between March 2009 and January 2012 were eligible for this survey. Neurological symptoms had to last for more than 24 h (consistent with the original WHO criteria [10]) unless thrombolytic therapy was applied. Only patients with computed tomography (CT) or MRI excluding hemorrhagic stroke were enrolled into the study. Patient characteristics on hospital admission/during hospitalization for acute stroke were retrospectively retrieved from their medical records. All eligible patients with complete data on admission and discharge BP (except for patients with missing discharge BP due to in-hospital death) were included in the analysis. The subtype of acute ischemic stroke was classified using a validated computerized algorithm for causative classification of ischemic stroke [Causative Classification of Stroke System (CCS)] [11] by two independent blinded physicians certified in CCS classification. Disagreements on stroke cause classification were discussed. The neurological severity on admission was assessed using the National Institute of Health Stroke Scale (NIHSS) score. Hypertension was defined as a history of hypertension or use of antihypertensive drugs. Diabetes was defined as a history of diabetes or antidiabetic treatment. Dyslipidemia was defined as a history of dyslipidemia or use of lipid-lowering drugs. The study was approved by the joint local Ethics Committee of the Institute for Clinical and Experimental Medicine and Thomayer Hospital, Prague, Czech Republic. All participants provided their informed written consent.
Blood pressure measurement SBP and DBP values on hospital admission, maximal BP during hospitalization, and BP at discharge were retrieved from medical records. Pulse pressure (PP) was calculated as the difference between SBP and DBP. Mean blood pressure (MBP) was calculated as MBP ¼ DBP þ [(SBP DBP)/3].
Clinical outcome The outcome in the present study is total mortality, which was assessed from the General Health Insurance Company registry that keeps, by law, a list of all people insured and deceased. The median follow-up was 66 weeks [interquartile range (IQR) 33–119 weeks].
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
