Methodological factors affecting quantification of blood pressure variability: a scoping review

Sleep and blood pressure variability: A systematic literature review

BACKGROUND

Blood pressure variability (BPV) is a prognostic marker of cardiovascular disease (CVD). Sleep is recognized as a significant risk factor for CVD; however, little is known about the relationship between sleep characteristics and BPV.

OBJECTIVE

In this systematic review, we aimed to (1) describe methods used to measure BPV and sleep and (2) describe the current evidence in the literature on the association between sleep and BPV.

METHODS

A systematic search was conducted using the search terms "sleep" AND ("blood pressure variability" OR "ambulatory blood pressure monitor") in CINAHL, PubMed, Web of Science, and PsycINFO databases.

RESULTS

Twenty-two studies were included in this systematic review. Sleep was measured using various methods, including polysomnography, actigraphy, sleep diaries, and questionnaires, while BPV was measured over various time intervals using different monitoring devices such as a beat-to-beat blood pressure (BP) monitoring device, a 24-h ambulatory BP monitor, or an automatic upper arm BP monitor. The studies demonstrated mixed results on the associations between sleep parameters (sleep quality, architecture, and duration) and increased BPV.

CONCLUSIONS

Although the mechanisms that explain the relationship between sleep and BPV are still unclear, accumulating evidence suggests potential associations between increased BPV with poor sleep quality and longer sleep duration. Given the recent development of sleep and BP monitoring technologies, further research is warranted to assess sleep and BPV under free-living conditions. Such studies will advance our understanding of complex interactions between sleep and CVD risk.

Exploring the link between blood pressure variability and atrial fibrillation: current insights and future directions

Atrial fibrillation (AF) is the most common heart rhythm disorder, especially in people over the age of 50, which affects more than 40 million people worldwide. Many studies have highlighted the association between hypertension with the development of AF. Blood pressure variability (BPV) is a dynamic size obtained by recording blood pressure oscillations using specific readings and at specific time intervals. A multitude of internal and external factors shape BPV while at the same time constituting a common pathogenetic pathway with the development of AF. Until recently, BPV has been applied exclusively in preclinical and clinical studies, without significant implications in clinical practice. Indeed, even from the research side, the determination of BPV is limited to patients without AF due to doubts about the accuracy of its measurement methods in patients with AF. In this review, we present the current evidence on common pathogenic pathways between BPV and AF, the reliability of quantification of BPV in patients with AF, the prognostic role of BPV in these patients, and discuss the future clinical implications of BPV in patients with AF.

Significance of pulse pressure variability in predicting functional outcome in acute ischemic stroke: a retrospective, single-center, observational cohort study

This study aimed to determine the association between pulse pressure variability (PPV) and short- and long-term outcomes of acute ischemic stroke (AIS) patients. We studied 203 tertiary stroke center patients with AIS. PPV during 72 h after admission was analyzed using different variability parameters including standard deviation (SD). Patients' outcome was assessed after 30 and 90 days post-stroke with modified Rankin Scale. The association between PPV and outcome was investigated using logistic regression analysis with adjustment for potential confounders. The predictive significance of PPV parameters was determined using area under the curve (AUC) of receiver operating characteristics. In the unadjusted logistic regression analysis, all PPV indicators were independently associated with unfavorable outcome at 30 days (i.a. Odds ratio (OR) = 4.817, 95%CI 2.283-10.162 per 10 mmHg increase in SD, p = 0.000) and 90 days (i.a. OR = 4.248, 95%CI 2.044-8.831 per 10 mmHg increase in SD, p = 0.000). After adjustment for confounders, ORs for all PPV indicators remained statistically significant. On the basis of AUC values, all PPV parameters were found relevant outcome predictors (p < 0.01). In conclusion, elevated PPV during first 72 h after admission due to AIS is associated with unfavorable outcome at 30 and 90 days, independent of mean blood pressure levels.

Vascular frailty, a proposal for new frailty type: A narrative review

Frailty is the incremental accumulation of minute defects that progressively impair health and performance. Frailty is commonly observed in older adults; however, secondary frailty may also occur in patients with metabolic disorders or major organ failure. In addition to physical frailty, several distinct types of frailty have been identified, including oral, cognitive, and social frailty, each of which is of practical importance. This nomenclature suggests that detailed descriptions of frailty can potentially advance relevant researches. In this narrative review, we first summarize the clinical value and plausible biological origin of frailty, as well as how to appropriately assess it using physical frailty phenotypes and frailty indexes. In the second part, we discuss the issue of vascular tissue as a relatively underappreciated organ whose pathologies contribute to the development of physical frailty. Moreover, when vascular tissue undergoes degeneration, it exhibits vulnerability to subtle injuries and manifests a unique phenotype amenable to clinical assessment prior to or accompanying physical frailty development. Finally, we propose that vascular frailty, based on an extensive set of experimental and clinical evidence, can be considered a new frailty type that requires our attention. We also outline potential methods for the operationalization of vascular frailty. Further studies are required to validate our claim and sharpen the spectrum of this degenerative phenotype.

Blood Pressure Variability and Cognitive Function: a Scoping Review

PURPOSE OF REVIEW

To conduct a scoping review of articles which have evaluated BPV and cognitive function. Articles with keywords, titles or abstracts containing the terms 'cognitive' OR 'cognition' OR 'dementia' AND 'blood pressure variability' were identified from CINAHL, Medline, PMC and Web of Science.

RECENT FINDINGS

Methods of acquisition and analysis of BPV and cognitive measurements and their relationship were extracted from selected articles. Of 656 studies identified, 53 articles were selected. Twenty-five evaluated long-term (LTBPV), nine mid-term (MTBPV), 12 short-term (STBPV) and nine very short-term BPV (VSTBPV) with conflicting findings on the relationship between BPV and cognition. Variations existed in devices, period and procedure for acquisition. The studies also utilized a wide range of methods of BPV calculation. Thirteen cognitive assessment tools were used to measure global cognition or domain functions which were influenced by the population of interest. The interpretation of available studies was hence limited by heterogeneity. There is an urgent need for standardization of BPV assessments to streamline research on BPV and cognition. Future studies should also establish whether BPV could be a potential modifiable risk factor for cognitive decline, as well as a marker for treatment response.

Impact of COVID-19 lockdown on health parameters and muscle strength of older women: A longitudinal study

OBJETIVES

The present study aimed to evaluate the effect of a 13-week COVID-19 lockdown on health-related parameters in women aged 60-70 years.

STUDY DESIGN

Thirty women participated in this longitudinal study. All the assessments were performed before and 13 weeks after the initial phase of the COVID-19 pandemic in Spain (March to June 2020).

MAIN OUTCOME MEASURES

A sociodemographic questionnaire was provided, and tests were performed to assess muscle strength, anthropometric measurements, densitometry, blood pressure, blood parameters, Mediterranean diet adherence, and physical activity levels.

RESULTS

After the lockdown, both healthy and unhealthy lifestyle groups showed a significant worsening of HDL, cholesterol/HDL lipids, and isometric knee extension strength parameters. However, individuals with an unhealthy lifestyle also showed a significant worsening in LDL lipids, Non-HDL lipids, bone mineral density of the femoral neck, fat mass/height (%), truncal fat mass (absolute and percentage), total fat mass (absolute and percentage) and handgrip strength.

CONCLUSIONS

The COVID-19 pandemic had a negative impact on the overall health status of Spanish older women, potentially increasing their susceptibility to comorbidities, such as lipid cholesterol, body fat, and decreased muscle strength.

Blood pressure variability in individuals with diabetes mellitus: a scoping review

OBJECTIVES

to map methods and devices used to assess very short-, short-, medium-, and long-term pressure variability in adults with type 1 or 2 diabetes mellitus.

METHODS

scoping review conducted in January and February 2021 in MEDLINE, Web of Science, CINAHL, LILACS, PubMed, and Embase databases. Studies conducted within the last ten years analyzing pressure variability in adult and older patients with diabetes mellitus type 1 or 2 were included. Studies that used discontinued devices were excluded.

RESULTS

the sample was composed of 25 articles published since 2017, with the majority developed in Japan (n=11); with the predominance of the oscillometric method (n=22); the most used devices were from the Omron® brand (n=14); the most detected type was long-term variability (n=10).

CONCLUSIONS

we observed the increasing application of the oscillometric method for pressure variability analysis with various brands and models of automatic devices.

12-Month Results From the Unblinded Phase of the RADIANCE-HTN SOLO Trial of Ultrasound Renal Denervation

OBJECTIVES

This study reports the 12-month results of the RADIANCE-HTN (A Study of the ReCor Medical Paradise System in Clinical Hypertension) SOLO trial following unblinding of patients at 6 months.

BACKGROUND

The blood pressure (BP)-lowering efficacy and safety of endovascular ultrasound renal denervation (RDN) in the absence (2 months) and presence (6 months) of antihypertensive medications were previously reported.

METHODS

Patients with daytime ambulatory BP ≥135/85 mm Hg after 4 weeks off medication were randomized to RDN (n = 74) or sham (n = 72) and maintained off medication for 2 months. A standardized medication escalation protocol was instituted between 2 and 5 months (blinded phase). Between 6 and 12 months (unblinded phase), patients received antihypertensive medications at physicians' discretion. Outcomes at 12 months included medication burden, change in daytime ambulatory systolic BP (dASBP) and office or home systolic BP (SBP), visit-to-visit variability in SBP, and safety.

RESULTS

Sixty-five of 74 RDN patients and 67 of 72 sham patients had 12-month dASBP measurements. The proportion of patients on ≥2 medications (27.7% vs. 44.8%; p = 0.041), the number of medications (0 vs. 1.4; p = 0.015), and defined daily dose (1.4 vs. 2.2; p = 0.007) were less with RDN versus sham. The decrease in dASBP from baseline in the RDN group (-16.5 ± 12.9 mm Hg) remained stable at 12 months. The RDN versus sham adjusted difference at 12 months was -2.3 mm Hg (95% confidence interval [CI]: -5.9 to 1.3 mm Hg; p = 0.201) for dASBP, -6.3 mm Hg (95% CI: -11.1 to -1.5 mm Hg; p = 0.010) for office SBP, and -3.4 mm Hg (95% CI: -6.9 to 0.1 mm Hg; p = 0.062) for home SBP. Visit-to-visit variability in SBP was smaller in the RDN group. No renal artery injury was detected on computed tomographic or magnetic resonance angiography.

CONCLUSIONS

Despite unblinding, the BP-lowering effect of RDN was maintained at 12 months with fewer prescribed medications compared with sham.

Impact of visit-to-visit blood pressure variability on hypertensive-mediated target organ damage and future cardiovascular events: the Campania salute network

BACKGROUND

Exaggerated variability of blood pressure (BP) poses additional stress on cardiovascular system independent of BP average value, increasing risk of target organ damage (HMOD) and cardiovascular events. We assessed the impact of visit-to-visit variability (VVV) of BP on development of cardiovascular events and HMOD.

METHODS

Standard deviation (SD) and coefficient of variability of mean SBP and DBP were calculated in 3555 patients from the Campania Salute Network registry, with available echocardiogram and more than six visits during follow-up. Values from the first visit were excluded. The impact of VVV of BP on cardiovascular events, and mediation of HMOD were assessed at final visit.

RESULTS

Mean number of visits was 11 ± 6 with mean interval between visits of 9.1 ± 3.7 months. Mean visit-to-visit SD during follow-up was 13 ± 5 for systolic and 8 ± 3 mmHg for DBP; coefficients of variability were 9.7 ± 3.5 and of 9.6 ± 3.2, respectively. In multivariable analysis, left ventricular mass at follow-up was correlated with systolic VVV of BP independently of significant effect of age, BMI, mean SBP during follow-up and initial left ventricular mass. Follow-up GFR was inversely associated with systolic and diastolic VVV, independently of significant effect of age, mean glucose and SBP during follow-up, and initial GFR. In Cox regression, high VVV of BP was also associated with increased risk of cardiovascular events (hazard ratio 1.49, 95% confidence interval 1.08-2.06, P = 0.015), independently of significant effect of HMOD.

CONCLUSION

VVV is associated with prevalent HMOD and development of cardiovascular events, independently of mean BP value during follow-up and HMOD.

Prognostic impact of short-term ambulatory blood pressure variability for microvascular and macrovascular outcomes in patients with type 2 diabetes: the Rio de Janeiro Type 2 Diabetes Cohort Study

OBJECTIVE

To evaluate the prognostic importance of short-term blood pressure variability (BPV) for the occurrence of macrovascular and microvascular complications in individuals with type 2 diabetes.

METHODS

Six hundred and forty patients had 24-h ambulatory BP monitoring performed at baseline and were followed-up over a median of 11.2 years. Daytime, night-time and 24-h SBP and DBPV parameters (standard deviations and variation coefficients) were calculated. Multivariate Cox analysis, adjusted for risk factors and mean BPs, examined the associations between BPV and the occurrence of microvascular (retinopathy, microalbuminuria, renal function deterioration, peripheral neuropathy) and macrovascular complications [total cardiovascular events (CVEs), major adverse CVEs [MACEs]), and cardiovascular and all-cause mortalities. Improvements in risk discrimination were assessed by the C-statistic and Integrated Discrimination Improvement (IDI) index.

RESULTS

During follow-up, 186 patients had a CVE (150 MACEs), and 237 patients died (107 from cardiovascular diseases); 155 newly developed or worsened diabetic retinopathy, 200 achieved the renal composite outcome (124 newly developed microalbuminuria and 102 deteriorated renal function), and 170 newly developed or worsened peripheral neuropathy. Daytime DBPV was the best predictor for all cardiovascular outcomes and mortality, with hazard ratios (for increments of 1SD) ranging from 1.27 (95% CI 1.09-1.48) for all-cause mortality to 1.55 (1.29-1.85) for MACEs, and it improved cardiovascular risk discrimination (with increases in C-statistic of up to 0.026, and IDIs of up to 22.8%). No BPV parameter predicted any microvascular outcome.

CONCLUSION

Short-term BPV, particularly daytime DBPV, predicts future development of macrovascular complications and mortality and improves cardiovascular risk discrimination in patients with diabetes.

Short-term outcome after ischemic stroke and 24-h blood pressure variability: association and predictors

To examine the association between blood pressure (BP) variability measured within 24 h after admission for acute ischemic stroke and functional outcome 30 days after stroke onset and to find outcome predictors. A total of 174 patients were included in this retrospective study. Supine BP was measured every 4 h during the first 24 h after admission. The functional outcome was assessed using the modified Rankin Scale. BP parameters including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and pulse pressure (PP) were examined. A set of six variability indices was calculated, including standard deviation (SD), successive variation (SV), difference between maximum and minimum value (DMM), and maximal successive change (MSC). Patients with high SBP or PP variability measures were significantly more likely to develop an unfavorable outcome. All PP variability indices displayed the highest correlations with the outcome. This association was confirmed in logistic regression analysis, both in univariable model and a model adjusted to the baseline National Institute of Health Stroke Scale score and mean BP (the OR for an unfavorable outcome following a 10-mmHg increase in SD, SV, MSC, and DMM parameters was in the interval 1.4-2.7, p < 0.05). Following receiver operating characteristic analysis, the PP parameters yielded area under the curve (AUC) values between 0.654 and 0.666, p < 0.005. Thus, in the acute phase of ischemic stroke, the SD and MSC indices of PP variability during the first 24 h after admission were robustly associated with patients' 30-day outcomes and served as predictors of unfavorable outcomes with thresholds of 14 and 26 mmHg, respectively.

Prognostic importance of visit-to-visit blood pressure variability for micro- and macrovascular outcomes in patients with type 2 diabetes: The Rio de Janeiro Type 2 Diabetes Cohort Study

BACKGROUND

The prognostic importance of an increased visit-to-visit blood pressure variability (BP-VVV) for the future development of micro- and macrovascular complications in type 2 diabetes has been scarcely investigated and is largely unsettled. We aimed to evaluate it in a prospective long-term follow-up study with 632 individuals with type 2 diabetes.

METHODS

BP-VVV parameters (systolic and diastolic standard deviations [SD] and variation coefficients) were measured during the first 24-months. Multivariate Cox analysis, adjusted for risk factors and mean BP levels, examined the associations between BP-VVV and the occurrence of microvascular (retinopathy, microalbuminuria, renal function deterioration, peripheral neuropathy) and macrovascular complications (total cardiovascular events [CVEs], major adverse CVEs [MACE] and cardiovascular and all-cause mortality). Improvement in risk discrimination was assessed by the C-statistic and integrated discrimination improvement (IDI) index.

RESULTS

Over a median follow-up of 11.3 years, 162 patients had a CVE (132 MACE), and 212 patients died (95 from cardiovascular diseases); 153 newly-developed or worsened diabetic retinopathy, 193 achieved the renal composite outcome (121 newly-developed microalbuminuria and 95 deteriorated renal function), and 171 newly-developed or worsened peripheral neuropathy. Systolic BP-VVV was an independent predictor of MACE (hazard ratio: 1.25, 95% CI 1.03-1.51 for a 1-SD increase in 24-month SD), but not of total CVEs, cardiovascular and all-cause mortality, and of any microvascular outcome. However, no BP-VVV parameter significantly improved cardiovascular risk discrimination (increase in C-statistic 0.001, relative IDI 0.9%).

CONCLUSIONS

Systolic BP-VVV was an independent predictor of MACE, but it did not improve cardiovascular risk stratification. The goal of anti-hypertensive treatment in patients with type 2 diabetes shall remain in controlling mean BP levels, not on decreasing their visit-to-visit variability.

Prognostic value of visit-to-visit systolic blood pressure variability related to diabetic kidney disease among patients with type 2 diabetes

BACKGROUND

This study aimed to evaluate the impact of visit-to-visit variability (VVV) of blood pressure on the risk of diabetic nephropathy and whether it provides additional predictive information among patients with type 2 diabetes mellitus (T2DM) in China.

METHODS

We included 12 630 T2DM patients during January 2008-December 2012 using a retrospective cohort design. VVV of SBP was assessed as standard deviation, coefficient of variation and variation independent of mean of the blood pressure readings during the measurement period. Hazard ratios and 95% confidence intervals were estimated for the associations of variability in SBP with risk of diabetes nephropathy by using Cox proportional hazards regression models. Risk prediction ability was assessed using C statistic, integrated discrimination improvement (IDI) and net reclassification index (NRI).

RESULTS

We found a dose-response relationship across quartiles of VVV SBP (P trend < 0.001). Hazard ratio in the highest quartile of SD SBP (≥9.2 mmHg) was 1.49 (1.16-1.93) as compared with the lowest quartile (<4.8 mmHg) after adjusted for mean SBP values, max SBP values and other covariates. Addition of SD SBP significantly improved risk prediction for diabetic kidney disease (DKD) [C statistic (from 0.664 to 0.673), IDI (0.0011, 95% CI: 0.0003-0.0104) and NRI (0.053, 95% CI: 0.0017-0.113)]. Results remained similar across different subgroups, sensitivity analyses or using coefficient of variation and variance independent of mean.

CONCLUSION

VVV of SBP is a significant risk factor of DKD among T2DM patients on top of mean and max BP values, which provides additional significant predictive information.

Association of Visit-to-Visit Variability of Blood Pressure with Cardiovascular Disease among Type 2 Diabetes Mellitus Patients: A Cohort Study

BACKGROUND

Increasing evidence has shown that visit-to-visit variability (VVV) of blood pressure (BP) is associated with an increased risk of cardiovascular disease (CVD). The objective of this study was to evaluate the impact of VVV of systolic blood pressure (SBP) and diastolic blood pressure (DBP) on the risk of CVD among patients with type 2 diabetes mellitus (T2DM) in China.

METHODS

We conducted a retrospective cohort study of 10,163 T2DM patients who were not previously diagnosed with CVD from January 2008 to December 2012 in Ningbo, China. The VVV of BP was calculated using five metrics, including standard deviation (SD), coefficient of variation (CV), variation independent of mean, average real variability, and successive variability (SV) of measurements, obtained over a 24-month measurement period. Hazard ratios and 95% confidence intervals (CIs) were estimated by Cox proportional hazards regression models for the associations of variability in BP with risk of CVD.

RESULTS

A total of 894 CVD events were observed during a median follow-up of 49.5 months. The hazard ratio in the highest quintile of SD of SBP was 1.24 (95% CI, 1.01 to 1.52) compared with patients in the lowest quintile. The association between higher VVV of DBP and risk of CVD was not consistent across different metrics and sensitivity analyses.

CONCLUSION

Higher VVV of SBP was associated with an increased risk of CVD, irrespective of the mean SBP level. Future studies are needed to confirm these findings.

Blood pressure variability and outcome in acute ischemic and hemorrhagic stroke: a post hoc analysis of the HeadPoST study

The Head Positioning in Acute Stroke Trial (HeadPoST) is a pragmatic, international, cluster crossover randomized trial of 11,093 patients with acute stroke assigned to a lying-flat (0°) or sitting-up (head elevated ≥30°) position. This post-hoc analysis aimed to determine the association between BPV and outcomes for patients from a wide range of international clinical settings and how the association was modified by randomized head position. BPV was defined according to standard criteria with the key parameter considered the coefficient of variation (CV) of systolic BP (SBP) over 24 hours. Outcome was ordinal 90-day modified Rankin Scale (mRS) score. The association was analyzed by ordinal, logistic regression, hierarchical, mixed models with fixed intervention (lying-flat vs. sitting-up), and fixed period, random cluster, and random cluster-period, effects. 9,156 (8,324 AIS and 817 ICH; mean age 68.1 years; 39.2% women) were included in the analysis. CV of SBP had a significant linear association with unfavorable shift of mRS at 90 days (adjusted odds ratio [OR] 1.06, 95% confidence interval [CI] 1.02-1.11; P=0.01). There was no heterogeneity of the association by randomized head positioning. In addition, CV of diastolic BP (DBP) (1.08, 1.03-1.12; P=0.001) over 24 hours post stroke, was significantly associated with 3-month poor outcome. The association was more apparent in sitting-up position (1.12, 1.06-1.19) compared with lying-flat position (1.03, 0.98-1.09) (P interaction = 0.005). BPV was associated with adverse stroke outcome, the magnitude of the association was greater with sitting-up head positioning in terms of DBP variability.

Blood pressure differences between home monitoring and daytime ambulatory values and their reproducibility in treated hypertensive stroke and TIA patients

BACKGROUND

Guidelines recommend ambulatory or home blood pressure monitoring to improve hypertension diagnosis and monitoring. Both these methods are ascribed the same threshold values, but whether they produce similar results has not been established in certain patient groups.

METHODS

Adults with mild/moderate stroke or transient ischemic attack (N = 80) completed 2 sets of ambulatory and home blood pressure monitoring. Systolic and diastolic blood pressure values from contemporaneous measurements were compared, and the limits of agreement were assessed. Exploratory analyses for predictive factors of any difference were conducted.

RESULTS

Daytime ambulatory blood pressure values were consistently lower than home values, the mean difference in systolic blood pressure for initial ambulatory versus first home monitoring was -6.6 ± 13.5 mm Hg (P≤.001), and final ambulatory versus second home monitoring was -7.1 ± 11.0mm Hg (P≤.001). Mean diastolic blood pressure differences were -2.1 ± 8.5mm Hg (P=.03) and -2.0 ± 7.2mm Hg (P=.02). Limits of agreement for systolic blood pressure were -33.0 to 19.9mm Hg and -28.7 to 14.5mm Hg for the 2 comparisons and for DBP were -18.8 to 14.5mm Hg and -16.1 to 12.2mm Hg, respectively. The individual mean change in systolic blood pressure difference was 11.0 ± 8.3mm Hg across the 2 comparisons. No predictive factors for these differences were identified.

CONCLUSIONS

Daytime ambulatory systolic and diastolic blood pressure values were significantly lower than home monitored values at both time points. Differences between the 2 methods were not reproducible for individuals. Using the same threshold value for both out-of-office measurement methods may not be appropriate in patients with cerebrovascular disease.