J Stroke Cerebrovasc Dis. 2016 Aug;25(8):1856-63.

High bedtime home blood pressure strongly predicts post stroke cognitive impairment. 

Yasumasa Yamamoto1, Yoshinari Nagakane2, Yasuhiro Tomii1, Eijiro, Tanaka2, Shinji Ashida2, Ichiro Akiguchi3 

Department of Neurology, Kyoto Katsura Hospital1, Kyoto Second Red Cross Hospital2, Kyoto Takeda Hospital1

 

Abstract

Background: Hypertension may be the most modifiable risk factors for the secondary prevention of stroke and for post stroke cognitive impairment (PSCI). However, the role of blood pressure (BP) and its various components has yet to be fully investigated in PSCI. Home blood pressure (HBP) monitoring has been identified to better predict cardiovascular and stroke risk than clinic blood pressure (CBP) measurement. We herein investigated how HBP can predict PSCI as well as stroke recurrence.

Methods: We studied 249 consecutive patients with non-cardioembolic minor ischemic stroke including single lacunar infarct (sLI), multiple lacunae (mLI) and atherothrombotic infarction, which were tracked at our outpatient clinic. All patients recorded HBP measured in the early morning (mHBP) and just before going to bed (bHBP) using an electric device based on the cuff-oscillometric principle. HBP categories based on SBP were created as follows: HB1; both mHBP and bHBP < 135 (mmHg), HB2; mHBP 135 and bHBP < 135, HB3; mHBP < 135 and bHBP 135, HB4; both mHBP and bHBP 135. After 4.1 years tracking, the patients were divided into four groups: Group 1, good outcome (n=188); Group 2, the development of silent infarcts (n=16); Group 3, stroke recurrence (n=15); and Group 4, the development of PSCI (n=33).

Results: In multivariate analysis, HB2 and HB4 (versus HB1) (HR: 6.5, p=0.0068, HR: 9.5, p=0.0008, respectively) and mLI (versus sLI) (HR: 4.0, p=0.021) were significantly associated with Group 2. HB4 (HR: 8.1, p=0.0002) and mLI (HR: 10.2, p=0.0003) were significantly associated with Group 3. HB3 and HB4 (HR: 4.2, p=0.037, HR: 5.4, p<0.0001, respectively) and mLI (HR: 6.4, p<0.0001) were significantly associated with Group 4. Namely, high bHBP with normal mHBP was significantly associated with PSCI, while high mHBP with normal eHBP was not associated. Clinic BP was not significantly associated with any adverse groups.

Conclusions: High HBP and multiple lacunae were strongly association with PSCI as well as stroke recurrence. Especially, bedtime HBP may be more crucial than morning HBP for the prevention of PSCI.

KEYWORDS: Home blood pressure; bedtime blood pressure; multiple lacunae; post-stroke cognitive impairment

Supplement: 

Hypertension is the strongest risk factor for stroke and the most modifiable risk factors for the secondary prevention of stroke and post stroke cognitive impairment (PSCI). Home blood pressure (HBP) monitoring has been established as to better predict cardiovascular and stroke risk than clinic blood pressure measurement. However, how HBP correlate with cognitive impairment, especially with PSCI, has not been clarified. HBP monitoring provides much BP information obtained under fixed times and conditions over a long period of time that ensures high reproducibility. High early morning blood pressure (mHBP) has been highlighted to be better associated with cardiovascular outcome than bedtime HBP. Bedtime HBP is sometimes considered to be unreliable because it is influenced by bathing or drinking alcohol. However, bedtime HBP (bHBP) may represent a blood pressure value that was measured in the most relaxing time in a day. It then can closely reflect nighttime blood pressure during sleep. We previously reported that non-dipper status or high nighttime blood pressure were strongly associated with post-stroke cognitive impairment in both cross-sectional and longitudinal studies. We then hypothesized that bHBP as well as mHBP can be for subsequent cognitive decline. 

Methods: We studied 249 consecutive patients with non-cardioembolic minor ischemic stroke including single lacunar infarct (sLI, n=125), multiple lacunae (mLI, n=84) and atherothrombotic infarction (n=43), which were tracked at our outpatient clinic. All patients recorded HBP measured in the early morning (mHBP) and just before going to bed (bHBP) using an electric device based on the cuff-oscillometric principle. The value of HBP of 7 successive days, during a period in which each patients BP seemed to be stable, were calculated as the average the measurements. HBP categories based on SBP were created as follows: HB1; both mHBP and bHBP < 135 (mmHg), HB2; mHBP 135 and bHBP < 135, HB3; mHBP < 135 and bHBP 135, HB4; both mHBP and bHBP 135. After 4.1 years tracking, the patients were divided into four groups: Group 1, good outcome (n=188); Group 2, the development of silent infarcts (n=16); Group 3, stroke recurrence (n=15); and Group 4, the development of PSCI (n=33).

Results: The values of mHBP and b HBP during follow up in different outcome groups were given in the Figure 1 and Figure 2. In multivariate analysis, HB2 and HB4 (versus HB1) (HR: 6.5, p=0.0068, HR: 9.5, p=0.0008, respectively) and mLI (versus sLI) (HR: 4.0, p=0.021) were significantly associated with Group 2. HB4 (HR: 8.1, p=0.0002) and mLI (HR: 10.2, p=0.0003) were significantly associated with Group 3. HB3 and HB4 (HR: 4.2, p=0.037, HR: 5.4, p<0.0001, respectively) and mLI (HR: 6.4, p<0.0001) were significantly associated with Group 4. Namely, high bHBP with normal mHBP was significantly associated with PSCI, while high mHBP with normal eHBP was not associated. Clinic BP was not significantly associated with any adverse groups.  

Conclusions: High HBP and multiple lacunae were strongly association with PSCI as well as stroke recurrence. If anything, bedtime HBP was more strongly associated with PSCI than morning HBP. The close relationship between bedtime BP and cognitive decline in the present study may be in line with studies that showed the relationship between high night time BP and cognitive decline using 24-hour blood pressure monitoring. While morning BP tends to rise highly influenced by sympathetic activity, bedtime BP tends to be reduced because of low sympathetic activity before going to a bed. However, when bedtime BP remains high, unusual condition such as non-dipper status should be considered. Whether or not bedtime BP is close to or reflects BP during sleep should be further examined. In the future, bedtime blood pressure should be paid more attention.

 

Legends

 

Figure 1. Morning HBP values. Group 2 through 4 were compared with Group 1. ***: p<0.0001

 

Figure 2. Bedtime HBP values. Group 2 through 4 were compared with Group 1. *: p<0.05, **: p<0.01, ***: p<0.0001

 

Figure 3. Odds ratio of covariates for recurrent stroke in multivariate analysis. *: p<0.05, ***: p<0.0001

 

Figure 4. Odds ratio of covariates for post-stroke cognitive impairment in multivariate analysis. ***: p<0.0001

 

Refferences

1.        Asayama K, Ohkubo T, Kikuya M, et al. Prediction of stroke by home “morning” versus “evening” blood pressure values: the Ohasama study. Hypertension. 2006; 48: 737-43.

2.        Yamamoto Y, Akiguchi I, Oiwa K, Hayashi M, Kimura J. Adverse effect of nighttime blood pressure on the outcome of lacunar infarct patients. Stroke. 1998; 29: 570-6.

3.        Yamamoto Y, Akiguchi I, Oiwa K, Hayashi M, Kasai T, Ozasa K. Twenty-four-hour blood pressure and MRI as predictive factors for different outcomes in patients with lacunar infarct. Stroke. 2002; 33: 297-305.

 

 

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