Degree Of Blood Pressure Variability Research Articles

Hemodynamics and Hemorrhagic Transformation After Endovascular Therapy for Ischemic Stroke.

Hemorrhagic transformation remains a potentially catastrophic complication of reperfusion therapies for the treatment of large-vessel occlusion ischemic stroke. Observational studies have found an increased risk of hemorrhagic transformation in patients with elevated blood pressure as well as a high degree of blood pressure variability, suggesting a link between hemodynamics and hemorrhagic transformation. Current society-endorsed guidelines recommend maintaining blood pressure below a fixed threshold of 180/105 mmHg regardless of thrombolytic or endovascular intervention. However, given the high recanalization rates with mechanical thrombectomy, it is unclear if the same hemodynamic goals from the pre-thrombectomy era apply. Also, individual patient factors such as the degree of reperfusion, infarct size, and collateral status likely need to be considered. In this review, we will discuss current evidence linking hemodynamics to hemorrhagic transformation after mechanical thrombectomy. In addition, we will review the clinical relevance of cerebral autoregulation in stroke, highlighting recent studies that have harnessed autoregulatory physiology to define and trend individualized limits of autoregulation. This review will go on to emphasize the translatability of this approach to stroke management. Finally, we will discuss novel statistical approaches like trajectory analysis to post-thrombectomy hemodynamics.

Impact of Resting Differences in Muscle Sympathetic Nerve Activity on Hemodynamic and Neural Responses to Exercise

Resting muscle sympathetic nerve activity (MSNA) displays high inter‐individual variability, yet the neural characteristics of those with high vs. low MSNA and resultant cardiovascular consequences are largely unclear. The purpose of this study was to examine blood pressure (BP) variability at rest and during exercise in individuals with high vs. low resting MSNA, and to characterize differences in resting sympathetic and cardiac baroreflex sensitivity (cBRS), in order to understand the accompanying neural characteristics and cardiovascular consequences of different levels of vasoconstrictor outflow. We retrospectively analyzed MSNA (microneurography) and continuous BP (Finometer) obtained at rest and during 2 minutes of static handgrip exercise at 30% maximal voluntary contraction from 60 young healthy men (n=30) and women (n=30). Within each sex, data was split into tertiles based on resting MSNA burst frequency and a comparative analysis was performed on the highest vs. lowest MSNA groups. BP variability was calculated as the beat‐to‐beat standard deviation. Spontaneous sympathetic baroreflex sensitivity (sBRS) was calculated using a weighted linear regression between diastolic blood pressure (DBP) and MSNA burst incidence. Threshold values (T50) were obtained by calculating the resting DBP associated with 50% of the MSNA bursts. cBRS was determined using the sequence technique. As expected, resting MSNA burst frequency was different between high and low groups (30±4 vs. 14±6 bursts/min [mean±SD], p<0.01), however, baseline anthropometrics, BP, heart rate, and cBRS sensitivity were not different (all, p>0.05). Resting DBP variability was lower in the high group (4±1 vs. 5±2 mmHg, p=0.05). sBRS was higher in the high group (−5.4±1.9 vs. −4.6±1.6 bursts/100 heartbeats/mmHg, p<0.01), and was correlated with resting MSNA (r=−0.46, p<0.01). T50 did not differ between the groups (60 vs. 55 mmHg, p>0.05), however, the prevailing mean DBP was above the T50 DBP to a lower extent in the high group (mean DBP – T50 DBP: 10±3 vs. 18±7 mmHg, p<0.01), and this value was negatively correlated with resting MSNA burst incidence (r=−0.76, p<0.01). During static handgrip exercise, BP and heart rate increased similarly in both groups (all, p>0.05), yet the increase in MSNA burst frequency was smaller in the high group (Δ 4±7 vs 10±6 bursts/min, p<0.01); similar results were obtained using MSNA burst incidence and total MSNA (both p<0.01). The change in burst frequency was unrelated to resting sBRS (r=0.23, p>0.05). Systolic BP variability was lower in the high group during exercise (7±3 vs 10±5 mmHg, p<0.05), but DBP variability was not different. In conclusion, differences in resting MSNA are unrelated to resting and exercising BP, but are likely associated with inter‐individual differences in the degree of BP variability and arterial baroreflex‐mediated suppression of MSNA. Further, baseline MSNA was found to influence the magnitude of the change during static handgrip exercise, though the hemodynamic consequences of these differences, and mechanisms responsible warrant further research.Support or Funding InformationNatural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant; Canada Foundation for InnovationThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Ambulatory blood pressure profiles in familial dysautonomia.

Familial dysautonomia (FD) is a rare genetic disease that involves extreme blood pressure fluctuations secondary to afferent baroreflex failure. The diurnal blood pressure profile, including the average, variability, and day-night difference, may have implications for long-term end organ damage. The purpose of this study was to describe the circadian pattern of blood pressure in the FD population and relationships with renal and pulmonary function, use of medications, and overall disability. We analyzed 24-h ambulatory blood pressure monitoring recordings in 22 patients with FD. Information about medications, disease severity, renal function (estimated glomerular filtration, eGFR), pulmonary function (forced expiratory volume in 1s, FEV1) and an index of blood pressure variability (standard deviation of systolic pressure) were analyzed. The mean (±SEM) 24-h blood pressure was 115±5.6/72±2.0mmHg. The diurnal blood pressure variability was high (daytime systolic pressure standard deviation 22.4±1.5mmHg, nighttime 17.2±1.6), with a high frequency of a non-dipping pattern (16 patients, 73%). eGFR, use of medications, FEV1, and disability scores were unrelated to the degree of blood pressure variability or to dipping status. This FD cohort had normal average 24-h blood pressure, fluctuating blood pressure, and a high frequency of non-dippers. Although there was evidence of renal dysfunction based on eGFR and proteinuria, the ABPM profile was unrelated to the measures of end organ dysfunction or to reported disability.

PP.26.10] AMBULATORY BLOOD PRESSURE VARIABILITY AND CARDIOVASCULAR RISK

Objective: The correlation of cardiovascular risk factor apoB/apoA1and nonHDL cholesterol to 24-hour blood pressure variability in hypertensive patients. Design and method: We studied 323 hypertensive treated or newly diagnosed untreated patients (average age: 51.1 yrs, average Systolic/Diastolic Blood Pressure:151/96.8 mmHg). They were subjected to 24-hour ambulatory blood pressure monitoring and their apoA1, apoB and nonHDL cholesterol plasma levels were measured. The degree of 24-hour Systolic/Diastolic Blood Pressure variability was divided in two groups: group A with systolic blood pressure levels greater or equal than 15mmHg and group B with systolic blood pressure levels less than 15mmHg. We sought the correlation between the apoB/apoA1 ratio to the degree of systolic and diastolic blood pressure variability (ANOVA method). Results: Analysis (ANOVA) of the apob/apoA1 ratio and nonHDL cholesterol variation in different groups:Conclusions: Both apob/apoA1 ratio and non-HDL cholesterol levels do not correlate to the 24-hour systolic blood pressure variability and are significantly lower in group A (that with the greater degree of blood pressure variability) for Diastolic Blood Pressure, posing significant doubt about the role of 24-hour diastolic pressure variability.

Impact of antihypertensive combination and monotreatments on blood pressure variability: assessment by old and new indices. Data from a large ambulatory blood pressure monitoring database.

High 24-h ambulatory blood pressure (ABP) variability is associated with poor cardiovascular outcomes. We analysed a large ABP monitoring database containing data from hypertensive patients treated with telmisartan/amlodipine combination or various monotherapies with the aim of quantifying the 24-h distribution of blood pressure (BP) reduction by treatment through the smoothness index and of developing and testing a new treatment-on-variability index (TOVI) to quantify the effects of treatment on both mean BP and BP variability. ABP data were pooled from 10 studies (N = 4294) with a median follow-up of 60 days. Smoothness index was calculated by dividing the mean of treatment-induced hourly BP reductions by its SD. TOVI was calculated as the ratio of the mean of hourly BP reductions to weighted 24-h BP SD (weighted mean of daytime and night-time SDs) under treatment. The SBP/DBP smoothness index and TOVI values of telmisartan/amlodipine combination were significantly (P < 0.0001) higher (smoothness index: 1.81/1.51; TOVI: 2.71/2.13) compared with telmisartan 80 mg (smoothness index: 1.12/0.90; TOVI: 1.55/1.23), amlodipine 10 mg (smoothness index: 1.33/1.09; TOVI: 2.09/1.58), valsartan 160 mg (smoothness index: 1.01/0.81; TOVI: 1.35/1.07), ramipril 10 mg (smoothness index: 0.83/0.63; TOVI: 1.11/0.87) and placebo (smoothness index: 0.23/0.18; TOVI: 0.34/0.30), indicating a smoother 24-h BP reduction profile (higher smoothness index) as well as the achievement of significantly lower and smoother BP levels over 24 h (higher TOVI) with the combination. As compared with various monotherapies, the telmisartan/amlodipine combination was associated with a smoother BP reduction over 24 h and with a more favourable balance between mean 24-h BP reduction and the degree of BP variability on treatment, reflecting both its effectiveness in lowering BP levels and its longer duration of action. The agreement between smoothness index and TOVI demonstrates that they are similarly effective in the differentiation of antihypertensive treatments, although providing conceptually different information, the clinical relevance of which needs to be tested by ad-hoc outcome studies.

Prognostic Value of Blood Pressure Variability and Average Blood Pressure Levels in Patients With Hypertension and Diabetes

Elevated blood pressure (BP) is a major risk factor for cardiovascular (CV) events and mortality (1) and a leading contributor to the global disease burden (2). Overwhelming evidence is now available showing that BP measured in the office shows a linear relationship with a number of CV and renal outcomes as well as with overall mortality and that lowering of office BP (OBP) with treatment is effective in reducing morbidity and mortality (3,4). However, application over the last 40 years of techniques for out-of-office BP monitoring including home BP monitoring (HBPM) and 24-h ambulatory BP monitoring (ABPM) has led to further important findings. In particular, 1 ) average BP measured in everyday life conditions may be an even better predictor of CV outcomes than isolated OBP readings and 2 ) the extent of fluctuations of BP over time may provide additional, independent prognostic information compared with both isolated office readings and average ambulatory BP (ABP) levels, respectively. These findings are of upmost relevance in the case of diabetic patients who are characterized by a significantly higher risk of CV events compared with nondiabetic individuals, with diabetes itself currently considered a CV disease equivalent (5,6). The aim of the present article is to review the available evidence on the prognostic importance of BP mean levels and of BP variability (BPV) estimates and to critically evaluate whether antihypertensive treatment strategies should be targeted at reducing not only average BP levels but also the degree of BPV in order to optimize CV protection in diabetic patients. ### Prognostic value of OBP values Consistent evidence from observational studies has indicated that the risk of CV morbidity and mortality has a strong and continuous relationship with OBP levels (3), without any evidence of a threshold down to at least 115/75 mmHg (4). Furthermore, large meta-analyses of major interventional trials …

Abstract 2802: Age and Stroke Severity Influence the Association between Blood Pressure Variability and Stroke Recovery

Blood pressure elevations after ischemic stroke are regarded as the body's response to maintain cerebral perfusion. Extremes of blood pressure have correlated with poor stroke recovery. Recently, blood pressure variability was shown to predict outcome better than mean blood pressures. Variables such as age, National Institute of Health stroke scale (NIHSS) and diabetes are established predictors of poor outcome and may potentially affect the degree of blood pressure variability. Our hypothesis was that age, NIHSS and diabetes would influence the association between blood pressure variability and stroke recovery. Methods: a retrospective chart review of consecutive patients discharged with an acute ischemic stroke based on ICD-9 codes was conducted. Successive blood pressure recordings during the 1st 5 days of hospitalization were noted. Blood pressure variability was calculated for systolic, diastolic and mean arterial pressures separately using published methods. Demographics, comorbidities, and modified Rankin score (mRS) at discharge were abstracted. Results: The study included 295 stroke patients, (median age 60 years; median NIHSS of 4.0). Age &gt;60, NIHSS 4-9, NIHSS ≥ 10 and diabetes were associated with poor recovery (mRS 3-6). The mean pressures in the study group ranged from 105-195 mmHg for systolic blood pressure (SBP), 51-159 mm Hg for diastolic blood pressure and 70-163 mm Hg for mean arterial pressure. The median variability for SBP was 21.0mmHg; diastolic blood pressure was 12.7mmHg; mean arterial pressure was 13.6mmHg. Subjects with higher SBP variability (greater than the median of 21.0) had significantly higher rates of poor recovery. Stratifying by age, the association of SBP variability and poor outcome was significant for age &gt; 60(OR: 2.16; 95%CI 1.06-4.38) but not for the younger subgroup with age≤ 60. Stratifying by stroke severity, the association of SBP variability and poor recovery was significant for NIHSS 4-9 (OR 3.41; 95%CI 1.55-8.23). All patients with high SBP variability in the NIHSS ≥ 10 group had poor recovery. The association was also significant in the subgroup without diabetes (OR 1.97; 95%CI 1.10-3.51), not in the subgroup of diabetic patients. Overall, the odds of a poor recovery due to high SBP variability were highest among subjects &gt; 60 years with moderate to high NIHSS. Conclusions: SBP variability in acute ischemic stroke is especially harmful among the elderly, nondiabetic and the more severe strokes. Extreme caution is advised when prescribing blood pressure lowering medications in these subgroups.

Blood Pressure Variability

Blood pressure (BP) values change significantly over time in response to environmental, behavioral, and emotional stimuli. These variations represent a complex phenomenon, and their assessment is possible by means of different BP measurement methodologies over different time windows: from beat to beat [very short-term BP variability (BPV)], within 24 h (from minute to minute, hour to hour and from day to night; short-term BPV), over different days (midterm day-by-day BPV), or between clinic visits performed over weeks, months, seasons, and years (long-term BPV) [1]. While in physiological conditions these variations represent an adaptive response to environmental stimulations from daily life, they may also reflect, however, alterations in cardiovascular regulatory mechanisms or underlying pathological conditions. The clinical significance of BPV has been supported by a large body of evidence showing that the BP-related cardiovascular risk may depend not only on average BP levels but also on the degree of BPV. Either in the short term (24 h), in the midterm (day-by-day), or in the long term (visit-to-visit), increasing values of BPV have been shown to be associated with development, progression, and severity of cardiac, vascular, and renal organ damage and with an increased risk of cardiovascular events and cardiovascular and all-cause mortality (Fig. 28.1). The evidence is limited, however, regarding the question on whether increasing values of BP variability (considered as an early marker of autonomic dysregulation) may represent also a marker of future hypertension during the prehypertensive (or high normal BP) state. Aim of this chapter is to review the current evidence in the field of BPV regarding its mechanisms, the methodological aspects that should be considered for its assessment, its relevance and significance for cardiovascular prognosis as well as its potential for application in clinical practice. In its last part a brief mention is made on the possible role of BPV as a predictor of future hypertension, as well as on the possibility that the assessment of BPV might contribute to improve the management of subjects with high normal office BP elevation, also defined as prehypertension.

Blood pressure variability as a risk factor.

Blood pressure variability is clinically relevant because of the evidence that the degree of blood pressure fluctuation may independently contribute to organ damage and to the cardiovascular risk of hypertensive patients. This review will focus on the evidence available to support this concept. As such, data obtained from cross-sectional studies, longitudinal studies in humans and experimental studies in animals will be discussed. The possibility of antagonizing an excessive degree of blood pressure variability by administering drugs to provide a long-lasting and smooth antihypertensive action will also be discussed, as will the usefulness of mathematical indices aimed at quantifying the homogeneity of the blood pressure reduction by treatment.

Blood pressure variability, cardiovascular risk and antihypertensive treatment.

TWENTY-FOUR HOUR BLOOD PRESSURE PARAMETERS: The use of ambulatory blood pressure monitoring techniques has shown clearly that 24-h average blood pressure is more closely related to the end-organ damage of hypertension than isolated office blood pressure readings. It has also provided evidence that the degree of blood pressure variability over a 24-h period may be independently related to the cardiovascular complications of hypertension. However, all the available data on this issue come from cross-sectional studies, and prospective evidence on the actual prognostic value of 24-h blood pressure parameters has only recently been provided for daytime blood pressure variability. There is still no prospective evidence concerning overall 24-h blood pressure variability. ANTIHYPERTENSIVE AGENTS AND BLOOD PRESSURE VARIABILITY: Available antihypertensive agents are unable to effectively buffer blood pressure variability. However, drugs with a long-lasting antihypertensive effect and an optimal trough: peak ratio may at least prevent further iatrogenic increases in the amplitude of blood pressure fluctuations. BEAT-TO-BEAT BLOOD PRESSURE MONITORING: The ability of antihypertensive agents to actually reduce 24-h blood pressure variability needs to be demonstrated in future studies, using beat-to-beat blood pressure monitoring which is now possible by means of non-invasive techniques.

Structural cardiovascular alterations and blood pressure variability in human hypertension.

To evaluate the cardiovascular risk of hypertensive patients in relation to left ventricular hypertrophy, arteriolar hypertrophy and blood pressure variability, and the effects of antihypertensive treatment. In hypertensive subjects with marked left ventricular hypertrophy, cardiovascular problems are about three times more frequent than in hypertensives who do not have left ventricular hypertrophy. The evidence suggests, however, that a moderate degree of left ventricular hypertrophy may be compensatory and that regression of mild hypertrophy should not necessarily be pursued. An increased wall to lumen ratio leads to an increase in vascular resistance and thus promotes hypertension. Regression of this alteration with antihypertensive treatment appears to be both beneficial and achievable, although it is not clear whether all antihypertensive agents have the same effect. Moreover, there are methodological problems in determining whether a regression has actually been achieved. There is evidence to suggest that end-organ damage is more frequent and more marked in hypertensives with greater 24 h blood pressure variability. It appears that antihypertensive treatment does not easily reduce this variability, although the intermittent measurements taken by automatic monitoring devices do not fully reflect patterns of blood pressure variation. It may be that hypertensives with a greater degree of blood pressure variability can obtain a reduction in the magnitude of this variability with antihypertensive treatment.

Determinants of the awakening rise in systemic blood pressure in obstructive sleep apnea syndrome.

To investigate the factors responsible for the morning rise in blood pressure (BP) in obstructive sleep apnea syndrome (OSAS) we examined a group of 253 consecutive snorers or OSAS patients. On the basis of their AHI the patients were classified in four groups. BP was measured on the evening before sleep onset and on the following morning after 15 min of rest by a finger arterial pressure device (Finapres). In 150 subjects BP was monitored during the night by a Finapres device. In the morning BP increased in the patient group with an average difference of 9.9 +/- 0.5 mmHg for systolic (SBP) and 9.9 +/- 0.4 mmHg for diastolic pressure (DBP). The increase was significant in snorers and OSAS patients without differences between groups. The morning rise in SBP was related to diurnal values of SBP, age and AHI whereas the time spent in apnea and the diurnal values of DBP significantly contributed to the DBP increase. In the subgroup of 150 patients in whom BP was analyzed during sleep, the awakening increase was related to the absolute BP value during sleep and to the BP changes from wakefulness to sleep. The magnitude of the BP changes from evening to morning was not dependent on the degree of BP variability during sleep. We conclude that the awakening increase in BP in patients with snoring or OSAS may be mediated by the setting of pressure response to apnea or to mechanical effort during sleep. Anthropometric variables and diurnal cardiovascular setting may play an additional role in modulating the final pressure response to upper airway obstruction.

Borderline hypertension, daily stress and psychological variables

AbstractBorderline hypertensive patients (N = 33) were studied in order to ascertain if they showed a specific psychological profile and a greater emotional and cardiovascular reactivity than normotensive controls (N = 21). Borderline hypertensive patients scored significantly higher in type A behaviour (JAS), total hostility (BDI), anxiety, physical symptoms and general psychopathology (GHQ), but did not differ from controls in the frequency and intensity of stressful daily events, the quality and magnitude of emotional response (daily evaluated through visual analogue scales) and the degree of blood pressure variability. Taken in general, results did not confirm the psychological and psychophysiological profile repeatedly proposed for hypertensive patients.

24-hour blood pressure measurements: methodological and clinical problems.

Awareness that sphygmomanometry is encompassed with serious limitations has led to the development of techniques that allow blood pressure (BP) to be monitored intraarterially or noninvasively during the day or over a 24-hour period. Although intraarterial BP monitoring allows an accurate evaluation of 24-hour BP mean and variability, its invasiveness prevents routine use in the clinical practice. This use can be more easily foreseen for noninvasive ambulatory BP monitoring, provided that the questions posed by this approach are answered. In the present study we show that the intermittent cuff inflations which allow BP to be measured noninvasively do not induce an alerting reaction and a BP rise in the patients, which means that this approach does not disrupt the daily BP profile. We also show that noninvasive BP monitoring does not alter the nocturnal hypotension, thus, preserving the day and night BP rhythm. Finally, we present evidence from a cross-sectional study that 24-hour BP monitoring reflects more closely the hypertension-related target organ damage than sphygmomanometric BP measurement and that target organ damage is related not only to average BP regimens but also to the degree of BP variability. Although support from prospective studies is necessary, this suggests that the diagnosis of hypertension and the prediction of its risk may be improved by ambulatory BP monitoring.