Ambulatory blood pressure monitoring in stroke survivors: do we really control our patients?

Blood pressure trajectory of inpatient stroke rehabilitation patients from the Determining Optimal Post-Stroke Exercise (DOSE) trial over the first 12 months post-stroke

Background

High blood pressure (BP) is the primary risk factor for recurrent strokes. Despite established clinical guidelines, some stroke survivors exhibit uncontrolled BP over the first 12 months post-stroke. Furthermore, research on BP trajectories in stroke survivors admitted to inpatient rehabilitation hospitals is limited. Exercise is recommended to reduce BP after stroke. However, the effect of high repetition gait training at aerobic intensities (>40% heart rate reserve; HRR) during inpatient rehabilitation on BP is unclear. We aimed to determine the effect of an aerobic gait training intervention on BP trajectory over the first 12 months post-stroke.

Methods

This is a secondary analysis of the Determining Optimal Post-Stroke Exercise (DOSE) trial. Participants with stroke admitted to inpatient rehabilitation hospitals were recruited and randomized to usual care (n = 24), DOSE1 (n = 25; >2,000 steps, 40-60% HRR for >30 min/session, 20 sessions over 4 weeks), or DOSE2 (n = 25; additional DOSE1 session/day) groups. Resting BP [systolic (SBP) and diastolic (DBP)] was measured at baseline (inpatient rehabilitation admission), post-intervention (near inpatient discharge), 6- and 12-month post-stroke. Linear mixed-effects models were used to examine the effects of group and time (weeks post-stroke) on SBP, DBP and hypertension (≥140/90 mmHg; ≥130/80 mmHg, if diabetic), controlling for age, stroke type, and baseline history of hypertension.

Results

No effect of intervention group on SBP, DBP, or hypertension was observed. BP increased from baseline to 12-month post-stroke for SBP (from [mean ± standard deviation] 121.8 ± 15.0 to 131.8 ± 17.8 mmHg) and for DBP (74.4 ± 9.8 to 78.5 ± 10.1 mmHg). The proportion of hypertensive participants increased from 20.8% (n = 15/72) to 32.8% (n = 19/58). These increases in BP were statistically significant: an effect [estimation (95%CI), value of p] of time was observed on SBP [0.19 (0.12-0.26) mmHg/week, p < 0.001], DBP [0.09 (0.05-0.14) mmHg/week, p < 0.001], and hypertension [OR (95%CI): 1.03 (1.01-1.05), p = 0.010]. A baseline history of hypertension was associated with higher SBP by 13.45 (8.73-18.17) mmHg, higher DBP by 5.57 (2.02-9.12) mmHg, and 42.22 (6.60-270.08) times the odds of being hypertensive at each timepoint, compared to those without.

Conclusion

Blood pressure increased after inpatient rehabilitation over the first 12 months post-stroke, especially among those with a history of hypertension. The 4-week aerobic gait training intervention did not influence this trajectory.

Biomarkers levels and brachial and central blood pressure during the subacute phase of lacunar stroke and other ischemic stroke subtypes

We aimed to evaluate brachial and central blood pressure (BP) estimates and biomarker levels in lacunar ischemic stroke (IS) and other IS subtypes (nonlacunar stroke). We studied 70 functionally independent subjects consecutively admitted to our institution after a first episode of IS. Subjects with previous heart failure were excluded. BP was measured at admission and during the subacute phase of stroke (5-7 days after stroke onset). Aortic pulse wave velocity (aPWV), augmentation index (AIx), and 24 h brachial and central BP (24h-ABPM) were measured by means of a Mobil-O-Graph device during the subacute phase of stroke. Determination of N-terminal prohormone of brain natriuretic peptide (NT-proBNP), urinary albumin excretion, and echocardiography were performed in all subjects. After adjusting for age and clinical severity, lacunar IS had significantly higher levels of BP at admission (systolic BP 173 ± 37 vs 153 ± 28 mmHg, p = 0.006; diastolic BP: 97 ± 21 vs 86 ± 16 mmHg, p = 0.035) and during the subacute phase of stroke (systolic BP 152 ± 23 vs 134 ± 19 mmHg, p = 0.001; diastolic BP: 84 ± 14 and 77 ± 10 mmHg, respectively; p = 0.038) but lower NT-proBNP levels (median: 36,277 vs 274 pg/mL, p = 0.009) than nonlacunar IS. Central BP, aPWV, and AIx were not different between lacunar and nonlacunar IS, neither the rate of target organ damage. In conclusion, patients with a first episode of lacunar IS have higher BP values at admission and during the subacute phase of stroke and lower levels of NT-proBNP, suggesting a closer relationship with hypertension of this IS subtype.

Chronic Management of Hypertension after Stroke: The Role of Ambulatory Blood Pressure Monitoring

Hypertension is the most important potentially reversible risk factor for stroke in all age groups; high blood pressure (BP) is also associated with increased risk of recurrent stroke in patients who have already had an ischemic or hemorrhagic event. Twenty-four hour ambulatory BP monitoring (ABPM) has become an important tool for improving the diagnosis and management of hypertension, and is increasingly used to assess patients with hypertension. Nevertheless, although ABPM devices are increasingly used for assessment of hypertension, their value in the chronic management of hypertension in patients with stroke has not been systematically studied. In fact, among large-scale randomized trials for secondary stroke prevention, only the Morbidity and Mortality After Stroke, Eprosartan Compared With Nitrendipine for Secondary Prevention trial included 24-hour ABPM. ABPM has demonstrated chronic disruption of the circadian rhythm of BP after acute phase of stroke and has shown higher sensitivity compared to office BP in evaluating the effectiveness of antihypertensive treatment among stroke survivors. High 24-hour BP is an independent predictor for cerebrovascular events, brain microbleeds, and subsequent development of dementia. Nevertheless, although stroke care guidelines endorse the importance of hypertension management, the specific role of ABPM among stroke survivors after the acute phase of disease has not been established. Further studies are needed to clarify whether routine application of ABPM among these patients should be recommended.

Post-exercise hypotensive responses following an acute bout of aquatic and overground treadmill walking in people post-stroke: a pilot study

BACKGROUND

The purpose of this study is to investigate the effects of a single-bout of aquatic treadmill walking (ATW) and overground treadmill walking (OTW) on the magnitude and duration of post-exercise ambulatory blood pressure (BP) in people post-stroke.

METHODS

Seven people post-stroke participated in a cross-sectional comparative study. BP was monitored for up to 9 hours after a 15-minute bout of ATW and OTW at approximately 70% of maximal oxygen consumption (VO2max), performed on separate days. Mean systolic and diastolic BP values were compared between both exercise conditions and a day without exercise (control).

RESULTS

Three hours after OTW, mean SBP increased by 9% from pre-exercise baseline compared to a 3% decrease during the control day (P < 0.05). A similar trend was observed after the third hour of ATW (P = 0.06). However, ATW demonstrated a 3% overall decline in DBP after exercise compared to a 1% DBP increase of the control day (P < 0.05). Additionally, ATW showed a 6% reduction in mean systolic BP at the ninth hour post-exercise (P < 0.05) compared to baseline.

CONCLUSION

Our results indicate people post-stroke can sustain sufficient walking intensities necessary to reduce BP following cardiovascular exercise. Also, these data suggest that ATW can elicit clinically meaningful reductions in DBP and night-time SBP. Thus, it is recommended for clinicians to consider ATW as a non-pharmaceutical means to regulate DBP and promote nighttime dipping of SBP in people post-stroke. However, caution is advised during the immediate hours after exercise, a period of possible BP inflation.

Ambulatory blood pressure in stroke and cognitive dysfunction

We have reviewed the most relevant data regarding ABPM and brain damage, with specific reference to first and recurrent stroke, silent structural brain lesions such as lacunar infarcts and white matter lesions, and cognitive impairment. Only two large studies have evaluated the usefulness of ABPM in relation to antihypertensive treatment in primary stroke prevention. In the Syst-Eur trial, drug treatment reduced ABPM and office BP more than placebo in patients with sustained isolated systolic hypertension (ISH). In contrast, in those patients with white-coat hypertension (WCH) changes in ABPM between the treatment groups were not significantly different. Patients with WCH had a lower incidence of stroke (p < 0.05) during follow-up than patients with sustained ISH, suggesting that WCH is a benign condition. In the HYVET trial 50 % of the very elderly patients included with office systolic BP > 160 mmHg had WCH. However, a significant 30 % stroke reduction was observed in treated patients including those with WCH, indicating that WCH may not be a benign condition in the elderly. In the acute stroke setting, where treatment of hypertension is not routinely recommended due to the lack of evidence and the differing results of the very few available trials, ABPM data shows that sustained high BP during the first 24 h after acute stroke is related to the formation of cerebral edema and a poorer functional status. On the other hand, even when nondipping status was initially related to a poorer prognosis, data indicate that patients with very-large nocturnal dipping, the so-called "extreme dippers", are those with the worse outcomes after stroke. The association between different ABPM parameters (circadian pattern, short-term variability) and poorer performance scores in cognitive function tests have been reported, especially in elderly hypertensives. Unfortunately most of these studies were cross-sectional and the associations do not establish causality.

Effect of clustering of metabolic syndrome factors on capillary and cerebrovascular impairment

BACKGROUND

Hypertension and metabolic disorders, attended by impaired microcirculation, represent major risk factors for cerebrovascular impairment, as well as being individual components of the metabolic syndrome (MetS). Aim of the study was to establish whether mild hypertensives, aged ≤65years, may be affected by progressive microvascular damage impairing cerebrovascular perfusion, related to a progressive clustering of MetS components.

METHODS

Twenty-two normotensives with no MetS component (NTN-0), 29 hypertensives with no (HTN-0), 30 with one (HTN-1), 29 with two (HTN-2), 27 with three (HTN-3), 25 with all four (HTN-4) MetS components, were recruited. The study required office and twenty-four hour ambulatory blood pressure monitoring and video capillaroscopy. Functional (fCD), anatomical (aCD) and recruited (RECR) phalangeal skin capillarity were assessed. Cerebral vasodilatory reserve was measured by the breath-holding index (BHI), using transcranial Doppler, in HTN-1 and HTN-2 with MetS.

RESULTS

The fCD and aCD were reduced in hypertensives and progressively reduced in those with MetS, while RECR was also impaired. BHI was lower in HTN-2 than in HTN-1 (p<0.001). BHI was correlated with fCD in HTN-1 (.396, p: .046), HNT-2 (.497, p: .011), and with aCD in HTN-2 (.494, p: .012), by partial Pearson test.

DISCUSSION

The findings show that hypertensives exhibit an increasing microvascular rarefaction with MetS progression and that an impaired cerebral perfusion occurs when the MetS is established. The data underline the importance of preventing MetS in mild hypertensives, as it causes microvascular damage and impairs cerebral arterial perfusion.

Effects of 24-Hour Blood Pressure and Heart Rate Recorded With Ambulatory Blood Pressure Monitoring on Recovery From Acute Ischemic Stroke

Background and Purpose—

This study used ambulatory blood pressure (BP) monitoring to generate BP and heart rate (HR) profiles soon after stroke onset and evaluated the association between determined values and 3-month stroke outcomes.

Methods—

We analyzed 24-hour ambulatory BP monitoring records from 104 patients with acute ischemic stroke. Ambulatory BP monitoring was attached at the second and eighth hospitalization days (Days 1 and 7). Both BP and HR were characterized using baseline, mean, maximum, and minimum values and coefficient of variation during 24-hour recording periods. Outcomes at 3 months were assessed as independence according to a modified Rankin Scale score of ≤2 and poor according to the score of ≥5.

Results—

Sixty-six (63%) patients achieved independence and 12 (11%) had poor outcomes. Mean ambulatory BP monitoring values changed from 150.5±19.5/85.7±11.3 mm Hg on Day 1 to 139.6±19.3/80.0±11.7 mm Hg on Day 7. After multivariate adjustment, mean values of systolic BP (OR, 0.63; 95% CI, 0.45–0.85), diastolic BP (0.61; 0.37–0.98), pulse pressure (0.55; 0.33–0.85), and HR (0.61; 0.37–0.98) recorded on Day 1 as well as mean HR on Day 7 (0.47; 0.23–0.87) were inversely associated with independence and mean values of systolic BP (1.92; 1.15–3.68), diastolic BP (5.28; 1.92–22.85), and HR (4.07; 1.83–11.88) on Day 1 as well as mean HR on Day 7 (4.92; 1.36–36.99) were positively associated with a poor outcome.

Conclusions—

All of systolic BP, diastolic BP, pulse pressure, and HR on Day 1 and HR on Day 7 assessed using ambulatory BP monitoring were associated with outcomes of patients with stroke at 3 months.

Nocturnal hypotension in patients after ischemic stroke: does it really matter?

BACKGROUND

We aimed to evaluate the presence of nocturnal hypotension (NHP) in ischemic stroke (IS) survivors using ambulatory blood pressure (BP) monitoring (ABPM).

METHODS

We included fifty consecutive patients presenting at our outpatient clinic for review and who had been discharged for IS in the previous six months. 24-h ABPM was performed with Spacelab 90207 monitor. NHP episodes were considered those values on which the mean arterial pressure (MAP)<70mm Hg. Patients were divided into two groups according to the presence or absence of NHP.

RESULTS

We studied 31 men and 19 women, mean age 68±11years. Episodes of NHP were observed in 21 patients (42%). There were no significant differences with regard to clinical characteristics between groups. With regard to BP, patients with NHP had significantly lower mean 24-hour BPs, mean daytime BPs and mean nighttime BPs. Dipper pattern occurred more often in patients with NHP, although differences were only statistically significant in the diastolic BP values. Mean office readings were 142±26/77±13mm Hg (149±26 versus 133±20; P=0.06; 82±12 versus 71±12; P=0.008). None of the patients showed office SBP <90mmHg and only four had office DBP <60mmHg.

CONCLUSIONS

Episodes of NHP in patients with recent IS are common and difficult to detect with clinical cuff measurements. It is necessary to redefine the target BP levels in secondary stroke prevention, possibly because we are subjecting our patients to increased risk of NHP and cerebral hypoperfusion.

The Effect of Transdermal Glyceryl Trinitrate on 24 h Ambulatory Blood Pressure in Acute/Subacute Stroke

Background

High blood pressure is a common complication in acute stroke and is associated with a poor outcome.

Aims

This study assesses the effects of transdermal glyceryl trinitrate on 24 h ambulatory blood pressure in patients with recent stroke.

Methods

One hundred and seven patients with acute ischaemic or haemorrhagic stroke were included. The patients had been enrolled in one of two trials of transdermal glyceryl trinitrate (5 mg daily) or placebo/control, and underwent 24 h ambulatory blood pressure monitoring (56 glyceryl trinitrate, 51 control). Ambulatory blood pressure data were analysed using area under the curve for the entire 24 h, and day and night periods. Nocturnal dipping was defined as a decline in systolic blood pressure >10%. Comparisons of blood pressure between groups were performed by analysis of covariance (ANCOVA) with adjustments for trial and baseline measure.

Results

In comparison with control, glyceryl trinitrate significantly lowered 24 h blood pressure (systolic blood pressure/ diastolic blood pressure 9·4/4·8 mmHg, P < 0·001/0·001, n = 104), daytime blood pressure (8·7/4·2, P < 0·001/ < 0·001, n = 103) and night-time blood pressure (6·9/1·7, P = 0·008/0·458, n = 86). Only 86 patients (glyceryl trinitrate 45, placebo/control 41) had sufficient night blood pressure measurements to assign dipping status; 28 were dippers (12 glyceryl trinitrate, 16 control) and 58 were nondippers (33 glyceryl trinitrate, 25 control); glyceryl trinitrate significantly lowered systolic but not diastolic blood pressure in both dippers and nondippers. Treatment with glyceryl trinitrate increased the daytime heart rate (4·8 beats/min) but not the night-time heart rate. Patients whose blood pressure did not dip at night had a worse functional outcome at three-months.

Conclusions

Transdermal glyceryl trinitrate (5 mg) significantly lowered 24 h blood pressure by 9/5 mmHg (equivalent to a 6% reduction) in both dipping and nondipping patients with acute/subacute stroke. This reduction in blood pressure is clinically relevant and is unlikely to be excessive.