Blood pressure load determines left ventricular mass in essential hypertension

Cumulative blood pressure load and hypertensive nephropathy in Han Chinese hypertensive patients

The study aims to assess the relationship between cumulative blood pressure load (cBPL) and the risk of renal function decline in hypertensive patients and determine the blood pressure (BP) threshold required to prevent hypertensive nephropathy. A single-center prospective cohort study was conducted on hypertensive patients. The cBPL was defined as the proportion of area beyond variable BP cutoffs under ambulatory BP monitoring. Renal events were defined as > 25% (minor) or > 50% (major) decline of baseline estimated glomerular filtration rate (eGFR). Cox regression analysis was conducted between cBPL, other ambulatory BP parameters, and renal events. The results revealed a total of 436 Han Chinese hypertensive patients were eligible for enrollment. During an average follow-up period of 5.1 ± 3.3 years, a decline of > 25% and > 50% in eGFR was observed in 77 and eight participants, respectively. Cox regression analysis revealed that cSBPL140 (hazard ratio [HR], 1.102; 95% confidence interval [CI], 1.017-1.193; p = .017), cSBPL130 (HR, 1.076; 95% CI, 1.019-1.137; p = .008), and cSBPL120 (HR, 1.054; 95% CI, 1.010-1.099; p = .015) were independently associated with minor renal events. Similarly, cSBPL140 (HR, 1.228; 95% CI, 1.037-1.455; p = .017), cSBPL130 (HR, 1.189; 95% CI, 1.045-1.354; p = .009), and cSBPL120 (HR, 1.155; 95% CI, 1.039-1.285; p = .008) were independently associated with major renal events. In conclusion, cBPL is associated with renal function decline in hypertensive patients. Minimizing cBPL120 may decrease the risk of hypertensive nephropathy.

The Role of Blood Pressure Load in Ambulatory Blood Pressure Monitoring in Adults: A Literature Review of Current Evidence

BACKGROUND

The blood pressure load (BPL) is commonly defined as the percentage of readings in a 24-h ambulatory blood pressure monitoring (ABPM) study above a certain threshold, usually the upper normal limit. While it has been studied since the 1990s, the benefits of using this index have not been clearly demonstrated in adults. We present the first review on the associations of BPL with target organ damage (TOD) and clinical outcomes in adults, the major determinants for its role and utility in blood pressure measurement. We emphasize studies which evaluated whether BPL has added benefit to the average blood pressure indices on ABPM in predicting adverse outcomes.

METHODS

PubMed search for all English language papers mentioning ABPM and BPL.

RESULTS

While multiple studies assessed this question, the cumulative sample size is small. Whereas the associations of BPL with various TODs are evident, the available literature fails to demonstrate a clear and consistent added value for the BPL over the average blood pressure indices.

CONCLUSIONS

There is a need for prospective studies evaluating the role of BPL in blood pressure measurement. The current literature does not provide sound support for the use of BPL in clinical decisions.

Does the Body Mass Index Category Influence Ambulatory Blood Pressure Parameters in Office Normotensive Obese Children?

The aim of our study was to investigate the influence of the degree of obesity on ambulatory blood pressure parameters in selected group of office normotensive obese children and adolescents. Our study involved 119 obese patients (55 males, 46.2%) aged 7-18 years divided into 3 groups based on their body mass index Z-score, who underwent ambulatory blood pressure monitoring. Our results show that obese patients, even when office normotensive, have alterations in blood pressure values obtained by ambulatory blood pressure monitoring. We found a positive correlation between systolic and diastolic blood pressure and body mass index in our patients (p [Formula: see text] 0.001). Daytime blood pressure load correlated with rising body mass index and was higher in groups II and III compared to group I (p < 0.001). Body mass index category did not influence the dipping pattern in our subjects although most of our subjects (66.4%) showed non-dipping pattern for systolic blood pressure. The difference in blood pressure variability was confirmed only for daytime systolic and diastolic values between groups I and II (p = 0.019 and p = 0.002, respectively). In conclusion, our study showed that in office normotensive obese children and adolescents, systolic and diastolic blood pressure values obtained by ambulatory blood pressure monitoring are higher in subjects with higher body mass index. Patients with increased body mass index also have higher percentage of blood pressure readings above 95^th percentile and increased daytime blood pressure variability. Obese patients show non-dipping pattern, independently of the rising body mass index category.

Cumulative Systolic Blood Pressure Load and Cardiovascular Risk in Patients With Diabetes

BACKGROUND

Standard measures of blood pressure (BP) do not account for both the magnitude and duration of exposure to elevated BP over time.

OBJECTIVES

The purpose of this study was to assess the association between cumulative systolic blood pressure (SBP) load and risk of cardiovascular events in patients with type 2 diabetes.

METHODS

A post hoc analysis of patients with type 2 diabetes followed by the ADVANCE-ON (Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation - Observational Study). Cumulative SBP load was defined as the area under curve for SBP values ≥130 mm Hg divided by the area under curve for all measured SBP values over a 24-month exposure period. HRs for the association between cumulative SBP load with major cardiovascular events and death were estimated using Cox models.

RESULTS

Over a median 7.6 years of follow-up, 1,469 major cardiovascular events, 1,615 deaths, and 660 cardiovascular deaths were observed in 9,338 participants. Each 1-SD increase in cumulative SBP load was associated with a 14% increase in major cardiovascular events (HR: 1.14; 95% CI: 1.09-1.20), 13% increase in all-cause mortality (HR: 1.13; 95% CI: 1.13-1.18), and 21% increase in cardiovascular death (HR: 1.21; 95% CI: 1.13-1.29). For the prediction of cardiovascular events and death, cumulative SBP load outperformed mean SBP, time-below-target SBP, and visit-to-visit SBP variability in terms of Akaike information criterion and net reclassification indexes.

CONCLUSIONS

Cumulative SBP load may provide better prediction of major cardiovascular events compared with traditional BP measures among patients with type 2 diabetes. These findings reinforce the importance of both the magnitude and duration of exposure to elevated SBP in assessing cardiovascular risk. (Action in Diabetes and Vascular Disease Preterax and Diamicron MR Controlled Evaluation Post Trial Observational Study [ADVANCE-ON]; NCT00949286).

Blood Pressure Load: An Effective Indicator of Systemic Circulation Status in Individuals With Acute Altitude Sickness

Background: Acute high altitude (HA) exposure results in blood pressure (BP) variations in most subjects. Previous studies have demonstrated that higher BP is potentially correlated with acute mountain sickness (AMS). The BP load may be of clinical significance regarding systemic circulation status.

Objectives: This study aimed to examine HA-induced BP changes in patients with AMS compared to those in healthy subjects. Further, we provided clinical information about the relationship between variations in 24-h ambulatory parameters (BP level, BP variability, and BP load) and AMS.

Methods: Sixty-nine subjects were enrolled and all participants ascended Litang (4,100 m above sea level). They were monitored using a 24-h ambulatory blood pressure device and underwent echocardiography within 24 h of altitude exposure. The 2018 Lake Louise questionnaire was used to evaluate AMS.

Results: The AMS group comprised more women than men [15 (65.2%) vs. 13 (28.3%), P < 0.001] and fewer smokers [4 (17.4%) vs. 23 (50.0%), P = 0.009]. The AMS group exhibited significant increases in 24-h BP compared to the non-AMS group (24-h SBP variation: 10.52 ± 6.48 vs. 6.03 ± 9.27 mmHg, P = 0.041; 24-h DBP variation: 8.70 ± 4.57 vs. 5.03 ± 4.98 mmHg, P = 0.004). The variation of mean 24-h cBPL (cumulative BP load) (mean 24-h cSBPL: 10.58 ± 10.99 vs. 4.02 ± 10.58, P = 0.016; 24-h mean cDBPL: 6.03 ± 5.87 vs. 2.89 ± 4.99, P = 0.034) was also obviously higher in AMS subjects than in non-AMS subjects after HA exposure. 24-h mean cSBPL variation (OR = 1.07, P = 0.024) and 24-h mean cDBPL variation (OR = 1.14, P = 0.034) were independent risk factors of AMS. Moreover, variation of 24-h mean cSBPL showed a good correlation with AMS score (R = 0.504, P < 0.001).

Conclusions: Our study demonstrated that patients with AMS had higher BP and BP load changes after altitude exposure than healthy subjects. Excessive BP load variations were associated with AMS. Thus, BP load could be an effective indicator regarding systemic circulation status of AMS.

Increased ambulatory arterial stiffness index and blood pressure load in normotensive obese patients

OBJECTIVES

It has been shown that blood pressure (BP) values measured in obese subjects are higher than the individuals with normal weight, even in normotensive limits. However, data concerning the Ambulatory Arterial Stiffness Index (AASI) and blood pressure load in normotensive obese subjects is lacking. This study was aimed to compare the ambulatory arterial stiffness index and blood pressure load in normotensive obese and healthy controls.

METHODS

One hundred normotensive obese and one hundred normal weight subjects were included in this study. All subjects underwent 24-hour ambulatory blood pressure monitoring. Ambulatory arterial stiffness index was calculated from 24-hour ambulatory blood pressure monitoring records. Ambulatory arterial stiffness index was defined as one minus the regression slope of unedited 24-h diastolic on systolic blood pressures. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) load values were calculated from 24-hour ambulatory blood pressure monitoring analysis.

RESULTS

Ambulatory arterial stiffness index of the obese subjects was significantly higher than the healthy controls (0.48±0.2 vs. 0.33±0.11, p<0.001). 24-hours systolic blood pressure and diastolic blood pressure loads were significantly higher in obese subjects. Logistic regression analysis revealed that body mass index (BMI) was an independent predictor for an abnormal ambulatory arterial stiffness ındex (≥0.50) (OR: 1.137, 95% CI: 0.915-1.001, p=0.004).

CONCLUSION

Blood pressure load and ambulatory arterial stiffness index are increased in normotensive obese patients. Moreover, body mass index is an independent predictor for an abnormal ambulatory arterial stiffness index. Our results indicate that obese subjects are at higher risk for future cardiovascular events despite normal office BP levels.

Prevalence of and risk factors for abnormal left ventricular geometrical patterns in hypertensive subjects administered irbesartan

Background

Distinct populations differ in LVH prevalence and impaired LV geometry. Currently, the prevalence of and risk factors for LV geometric patterns in Chinese hypertensives administered irbesartan have not been specifically addressed in large studies.

Methods

Totally 10,883 patients (6623 men and 4260 women) completed the survey, including 1181 hypertensives administered irbesartan (488 males and 693 females) that were finally enrolled. Based on LVMI and RWT derived from comprehensive echocardiography, the LV geometric patterns of irbesartan‐treated hypertensive individuals were classified into four types, including the normal, concentric remodeling, and concentric and eccentric hypertrophy groups. Logistic regression analysis was applied in males and females, respectively, for determining odds ratios (ORs) and 95% confidence intervals (CIs) for various potential risk factors for abnormal LV geometrical patterns in irbesartan‐treated hypertensives.

Results

The clinical and echocardiographic data differed significantly between males and females. The prevalence rates of concentric remodeling, concentric hypertrophy, and eccentric hypertrophy were 36.3%, 15.4%, and 6.1% in males, respectively, and 23.5%, 20.3%, and 23.8% in females, accordingly. Gender, daily dose of irbesartan, BMI, SBP, WtHR, and neck‐circumference were significantly associated with LV geometric patterns. After adjustment for confounding factors, risk factors for LVH and impaired LV geometry included SBP, WtHR in males, and MAU‐Cr and WtHR in females.

Conclusions

LVH and impaired LV geometric patterns are more prevalent in females (67.7%) compared with that in males (57.8%) among hypertensives upon irbesartan administration. For such population, risk factors beyond elevated blood pressure may be involved in the progression of LVH and impaired LV geometric patterns in both genders.

Prognostic Value of Ambulatory Blood Pressure Load in Pediatric CKD

BACKGROUND AND OBJECTIVES

Elevated BP load is part of the criteria for ambulatory hypertension in pediatric but not adult guidelines. Our objectives were to determine the prevalence of isolated BP load elevation and associated risk with adverse outcomes in children with CKD, and to ascertain whether BP load offers risk discrimination independently or in conjunction with mean ambulatory BPs.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied 533 children in the CKD in Children (CKiD) Study to determine the prevalence of normotension, isolated BP load elevation (≥25% of all readings elevated but mean BP normal), and ambulatory hypertension. We examined the association between these categories of BP control and adverse outcomes (left ventricular hypertrophy [LVH] or ESKD). We used c-statistics to determine risk discrimination for outcomes by BP load used either independently or in conjunction with other BP parameters.

RESULTS

Overall, 23% of the cohort had isolated BP load elevation, but isolated BP load elevation was not statistically significantly associated with LVH in cross-section (odds ratio, 1.8; 95% CI, 0.8 to 4.2) or time to ESKD (hazard ratio, 1.2; 95% CI, 0.7 to 2.0). In unadjusted cross-sectional analysis, every 10% higher systolic BP load was associated with 1.1-times higher odds of LVH (95% CI, 1.0 to 1.3), but discrimination for LVH was poor (c=0.61). In unadjusted longitudinal analysis, every 10% higher systolic BP load was associated with a 1.2-times higher risk of ESKD (95% CI, 1.1 to 1.2), but discrimination for ESKD was also poor (c=0.60). After accounting for mean systolic BP, systolic BP load was not statistically significantly associated with either LVH or ESKD. Findings were similar with diastolic BP load.

CONCLUSIONS

BP load does not provide additive value in discriminating outcomes when used independently or in conjunction with mean systolic BP in children with CKD.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2020_03_11_CPOD10130819.mp3.

Blood Pressure and Left Ventricular Hypertrophy in Patients on Different Peritoneal Dialysis Regimens

Objective

To examine the relation between the results of ambulatory 24-hour blood pressure monitoring (ABPM) and left ventricular mass index (LVMI), then to find the independent determinant for left ventricular hypertrophy (LVH) in peritoneal dialysis (PD) patients. Finally, to evaluate the differences in the clinical and cardiovascular characteristics between patients on continuous ambulatory PD (CAPD) and continuous cyclic PD (CCPD).

Design

An open, nonrandomized, cross-sectional study.

Setting

Divisions of nephrology and cardiology in a medical center.

Patients

Thirty-two uremic patients on maintenance PD therapy (22 patients on CAPD, and 10 on CCPD) without anatomical heart disease or history of receiving long-term hemodialysis.

Interventions

Home blood pressure (BP) and office BP were measured using the Korotkoff sound technique by sphygmomanometer. ABPM was employed for continuous measurement of BP. Echocardiography was performed for measurement of cardiac parameters and calculation of LVMI.

Main Outcome Measures

Multivariate logistic regression analysis was performed for independent determinant of LVH in PD patients. The differences in clinical and cardiovascular characteristics between CAPD and CCPD patients were compared.

Results

Simple regression analysis showed positive correlations between LVMI and the duration of hypertension, ambulatory nighttime BP/BP load/BP load > 30%, serum phosphate, calcium–phosphate product, ultrafiltration (UF) volume, and percentage of UF volume during the nighttime. A negative correlation was noted between LVMI and dipping. In multiple regression analysis, the duration of hypertension was the only variable linked to LVMI. In multivariate logistic regression analysis, only ambulatory nighttime systolic BP load > 30% had an independent association with LVH. There were correlations between office/home BP and ambulatory 24-hour BP. In addition, CCPD patients had higher LVMI, UF volume during the nighttime, and percentage of UF volume during the nighttime than those of CAPD patients.

Conclusions

In this study, ambulatory nighttime systolic BP load > 30% had an independent association with LVH. Office and home BP measurements were correlated with ABPM in PD patients. The result that CCPD patients had a higher LVMI than CAPD patients may be due to a relative volume overload during the daytime in CCPD patients.

Left ventricular geometry and risk of incident hypertension

OBJECTIVE

Left ventricular (LV) geometry change is an independent predictor for cardiovascular disease. However, data are equivocal on the association of echocardiographic parameters of LV geometry with incident hypertension. Thus, we were to investigate the risk of hypertension according to the baseline echocardiographic parameters of LV geometry.

METHODS

Study participants were 12 562 Koreans without hypertension who received echocardiography as an item of health check-up. They were divided into normotensive or prehypertensive group according to baseline blood pressure. In each group, study subjects were classified by quintiles of baseline echocardiographic parameters including left ventricular mass index (LVMI), relative wall thickness (RWT), interventricular septal thickness (IVST), posterior wall thickness (PWT) and IVST plus PWT and followed up for 5 years. Cox proportional hazards model was used in calculating adjusted HRs and their 95% CI for hypertension according to each quintile group. Area under the curve (AUC) analysis (AUC [95% CI]) was performed to compare the predictability of LVMI, RWT, IVST, PWT, IVST plus PWT for hypertension.

RESULTS

Prehypertensive group had the worse clinical and echocardiographic parameters in baseline analysis than normotensive group. The risk of hypertension significantly increased proportionally to baseline LVMI, RWT, IVST, PWI and IVST plus PWT above specific quintile levels, which was identified in both normotensive and prehypertensive group. In AUC analysis, IVST, PWT and IVST plus PWT showed a significantly increased AUC, compared with LVMI.

CONCLUSION

LV geometry change was significantly associated with the increased risk for hypertension in non-hypertensive individuals.

Interventricular Septum and Posterior Wall Thickness Are Associated With Higher Systolic Blood Pressure

Elevated blood pressure (BP) is a known factor that affects the structure of the left ventricle. The association between left ventricular hypertrophy (LVH) and BP in normotensive individuals is poorly understood. All individuals who underwent routine echocardiography and BP measurements as aircrew candidates for the Israeli Air Force in the years 2006 to 2012 were identified. Participants with normal values were included. Associations between echocardiographic characteristics and BP were studied. A total of 2386 participants were included. Mean systolic BP was 125.31±11.18 mm Hg and mean diastolic BP was 68.69±9.02 mm Hg. Interventricular septal (IVS) thickness was positively correlated with systolic BP (P<.001, correlation coefficient 0.121) and significantly inversely correlated with heart rate and hematocrit level (P<.001 for both). Men with evidence of IVS or posterior wall thickening on echocardiography, even within the normal range, may require a closer follow-up of BP.

Is blood pressure load associated, independently of blood pressure level, with target organ damage?

OBJECTIVE

Blood pressure (BP) load, defined as the percentage of abnormally elevated BP readings, is usually provided on the report of ambulatory BP monitoring. However, the usefulness of BP load is still uncertain. In the present study, we examined whether BP load would be associated, independently of BP level, with target organ damage.

METHODS

We recruited 869 individuals (430 men, mean age 51 years) who were referred for 24-h ambulatory BP monitoring and were off antihypertensive medication for at least 2 weeks. BP load was defined as the percentage of daytime and nighttime SBP/DBP readings at least 135/85 and at least 120/70 mmHg, respectively. Brachial-ankle pulse wave velocity (baPWV) and carotid-femoral pulse wave velocity (cfPWV), left ventricular mass index (LVMI) and urinary albumin-to-creatinine ratio (ACR) were determined as measures of target organ damage.

RESULTS

SBP and DBP load had a skewed distribution (P<0.001). In multivariate-adjusted categorical analyses, baPWV (13.8, 14.6 and 15.6 m/s), cfPWV (7.4, 7.7 and 8.4 m/s), LVMI (90.1, 94.8 and 100.7 g/m) and ACR (0.47, 0.58 and 0.77 mg/mmol) all increased from tertiles 1-3 of SBP load (P<0.001). However, these differences became nonsignificant (P ≥ 0.16) after additionally adjusted for 24-h SBP level. In a continuous analysis in individuals with a BP load greater than zero (n=838), adding the logarithmically transformed SBP load did not improve the fit of models relating measures of target organ damage to SBP level (P ≥ 0.14), except for cfPWV (P=0.01) that was however negatively associated with BP load. Analyses on DBP load produced similar results.

CONCLUSION

BP load was associated with target organ damage, but not independently of BP level.

Blood pressure load does not add to ambulatory blood pressure level for cardiovascular risk stratification

Experts proposed blood pressure (BP) load derived from 24-hour ambulatory BP recordings as a more accurate predictor of outcome than level, in particular in normotensive people. We analyzed 8711 subjects (mean age, 54.8 years; 47.0% women) randomly recruited from 10 populations. We expressed BP load as percentage (%) of systolic/diastolic readings ≥135/≥85 mm Hg and ≥120/≥70 mm Hg during day and night, respectively, or as the area under the BP curve (mm Hg×h) using the same ceiling values. During a period of 10.7 years (median), 1284 participants died and 1109 experienced a fatal or nonfatal cardiovascular end point. In multivariable-adjusted models, the risk of cardiovascular complications gradually increased across deciles of BP level and load (P<0.001), but BP load did not substantially refine risk prediction based on 24-hour systolic or diastolic BP level (generalized R(2) statistic ≤0.294%; net reclassification improvement ≤0.28%; integrated discrimination improvement ≤0.001%). Systolic/diastolic BP load of 40.0/42.3% or 91.8/73.6 mm Hg×h conferred a 10-year risk of a composite cardiovascular end point similar to a 24-hour systolic/diastolic BP of 130/80 mm Hg. In analyses dichotomized according to these thresholds, increased BP load did not refine risk prediction in the whole study population (R(2)≤0.051) or in untreated participants with 24-hour ambulatory normotension (R(2)≤0.034). In conclusion, BP load does not improve risk stratification based on 24-hour BP level. This also applies to subjects with normal 24-hour BP for whom BP load was proposed to be particularly useful in risk stratification.

Ambulatory blood pressure response to triple therapy with an angiotensin-receptor blocker (ARB), calcium-channel blocker (CCB), and HCTZ versus dual therapy with an ARB and HCTZ

BACKGROUND

Stage 2 hypertension often requires combination antihypertensive therapy. Ambulatory blood pressure monitoring (ABPM) is a useful tool for assessing antihypertensive drugs and their combinations.

OBJECTIVE

To compare the effect of a moderate dose of angiotensin receptor blocker/calcium channel blocker (ARB/CCB) combined with a diuretic versus a maximal dose of ARB with a diuretic on 24-hour ambulatory blood pressure monitoring (ABPM) and other derived ambulatory blood pressure (ABP) parameters.

METHODS

The EXforge As compared to Losartan Treatment ABPM substudy was a randomized, double-blind, parallel-group, active-control, forced-titration study of patients with Stage 2 hypertension that compared the efficacy of initial treatment with valsartan/amlodipine 160/5 mg (n = 48) or losartan 100 mg (n = 36). At week 3, hydrochlorothiazide (HCTZ) 25 mg was added in both treatment groups. ABP was measured at baseline and at week 6. Additionaly, 24-hour ABP, nighttime (10 pm to 6 am) and daytime (6 am to 10 pm) ABP, and ABP load (percentage of readings above 140/90 mmHg) were determined.

RESULTS

Eighty-four patients (48 ARB/CCB/HCTZ, 36 ARB/HCTZ) had ABPM at baseline and at week 6. Reductions of systolic/diastolic ABP were greater in the ARB/CCB/ HCTZ group than in the ARB/HCTZ group for 24-hour mean ABP (-22.0/-13.3 versus -17.4/-8.1 mmHg), as well as nighttime ABP (-22.2/-13.3 versus -16.2/-7.4 mmHg), daytime ABP (-21.9/-13.0 versus -18.1/-8.6 mmHg), ABP in the last 4 hours of the dosing period (-21.5/-13.5 versus -17.0/-7.7 mmHg), and ABP load (21.7%/12.8% versus 30.8%/20.0%).

CONCLUSION

Initiating antihypertensive treatment with moderate doses of ARB/CCB with a diuretic is more effective in lowering nighttime and daytime ABP and reducing ABP load than a maximal dose of an ARB with a diuretic.

Is the area under blood pressure curve the best parameter to evaluate 24-h ambulatory blood pressure monitoring data?

BACKGROUND

Ambulatory blood pressure monitoring (ABPM) provides relevant data about blood pressure over a 24-h period. The analysis of parameters to determine the blood pressure profile from these data is of great importance.

OBJECTIVES

To calculate areas under systolic and diastolic blood pressure curves (SBP-AUC/DBP-AUC) and compare with systolic and diastolic blood pressure load (SBPL/DBPL) and 24-h systolic and diastolic blood pressure (24-h SBP/24-h DBP) in order to determine which provides the best correlation with left ventricular mass index (LVMI).

METHODS

ABPM measurements (1143 individuals) were analyzed to obtain 24-h SBP/24-h DBP, SBPL/DBPL, and SBP-AUC/ DBP-AUC, using Spacelabs (90207) and CardioSistemas devices. Left ventricular mass was determined using an echocardiograph HP Sonos 5500 and LVMI was calculated.

RESULTS

The correlations between all possible pairs within the group 24-h SBP/SBPL/SBP-AUC and 24-h DBP/DBPL/DBP-AUC were high and statistically significant. The correlations between 24-h SBP/24-h DBP and SBP-AUC/DBP-AUC with SBPL/DBPL close to 100%, were lower than those mentioned above. The correlations of the parameters obtained by ABPM with LVMI were also high and statistically significant, except for blood pressure load between 90 and 100%, and for 24-h SBP of 135 mmHg or less and SBPL higher than 50%.

CONCLUSIONS

SBPL/DBPL and SBP-AUC/DBP-AUC can be used for the evaluation of ABPM data owing to the strong correlation with 24-h SBP/24-h DBP and with LVMI, except when SBPL is close to 100% or 24-h SBP is below 135 mmHg but SBPL is above 50%. SBP-AUC/DBP-AUC, however, are a better alternative because they do not have the limitations of blood pressure load or even of 24-h blood pressure present.

Ambulatory blood pressure monitoring: mean blood pressure and blood pressure load

Ambulatory blood pressure monitoring (ABPM) is commonly used to diagnose pediatric hypertension. Using ABPM, hypertension is usually defined as a mean BP greater than the 95th percentile for height. A BP load >30% (% of BP readings greater than the 95th percentile) is also used for the diagnosis of hypertension. The objective of this study was to determine the agreement between mean BP greater than the 95th percentile and 30% BP load for the diagnosis of hypertension using ABPM. All ABPM records (n =1,009) of patients referred for hypertension to a pediatric center were retrieved. Scans were excluded if: age was >19 and height <115 cm or >185 cm. Mean BP and BP loads were calculated for 728 scans. Agreement between mean BP greater than the 95th percentile for height and various BP loads were calculated using the kappa coefficient. The kappa coefficient of agreement between mean BP greater than the 95th percentile and 30% BP load was 0.56 and 0.57 for daytime systolic and diastolic BP, respectively. The agreement between mean night-time BP greater than the 95th percentile and 30% BP load was 0.70 and 0.66 for systolic and diastolic BP, respectively. Agreement between mean BP greater than the 95th percentile and 30% BP load is only moderate to good. Maximum agreement between mean BP greater than the 95th percentile and BP load is achieved at 50% BP load.

Relation of the G protein beta3-subunit polymorphism with left ventricle structure and function

The G protein beta3-subunit C825T polymorphism results in a truncated splice variant protein that is associated with enhanced transmembrane signaling, increased proliferative activity, and arterial hypertension. The aim of the present study was to further investigate the association of this polymorphism with left ventricular (LV) structure and function. A total of 2052 individuals from a large-scale population-based sample were investigated for the G protein beta3-subunit C825T polymorphism and echocardiographic parameters of LV structure and function. Complete genotyping and echocardiographic data were available in 1720 individuals (829 men and 891 women). The mean LV mass indices in men with CC (n=384) and TT (n=84) genotypes were 98.3+/-1.2 g/m2 and 100.0+/-2.8 g/m2, respectively (P=0.64). In women, the corresponding values were 83.1+/-1.0 g/m2 for the CC genotype (n=397) and 83.8+/-2.1 g/m2 for the TT genotype (n=91, P=0.32). Likewise, LV dimensions or parameters of the diastolic function and serologic markers of LV mass were not associated with the C825T variant. Finally, multivariate analyses accounting for potentially confounding factors failed to show any influence of this polymorphism on echocardiographic parameters. In conclusion, we were not able to confirm the previously published associations of the G protein beta3-subunit C825T polymorphism with LV structure and diastolic function.

Relationships between 24 h blood pressure load and target organ damage in patients with mild-to-moderate essential hypertension

OBJECTIVE

To analyse the relationships between 24 h blood pressure load (the percentage of systolic/diastolic blood pressures exceeding 140/90 mmHg while awake and 120/80 mmHg during sleep) and some indices of hypertensive target organ involvement, independently of the mean level of 24 h blood pressure.

METHODS

One hundred and thirty patients with mild-to-moderate hypertension underwent 24 h ambulatory blood pressure monitoring, ocular fundus examination, microalbuminuria assay and two-dimensional guided M-mode echocardiography. The study population was divided into subsets according to the systolic and diastolic 24 h blood pressure load values predicted from the regression equation relating 24 h blood pressure load to 24 h mean blood pressure. The subjects with an observed load above this predicted value were included in the higher blood pressure load groups, the remaining ones being included in the lower groups.

RESULTS

Relative myocardial wall thickness and total peripheral resistance were greater, and mid-wall fractional shortening, end-systolic stress-corrected mid-wall fractional shortening and cardiac index lower, in the subjects with a higher systolic blood pressure load. Moreover, the stroke index:pulse pressure ratio was reduced, and a greater prevalence of hypertensive retinopathy was observed in the higher systolic load group. On the contrary, no statistically significant difference was found for any of the cardiac, renal and funduscopic parameters examined when the two groups with a higher and lower 24 h diastolic blood pressure load were compared.

CONCLUSIONS

Our results seem to suggest that, in mild-to-moderate arterial hypertension, a high 24 h systolic blood pressure load may be associated, independently of the average level of 24 h systolic ambulatory blood pressure, with an adverse cardiovascular risk profile.

Comparison of enalapril to captopril by 24-hour ambulatory blood pressure monitoring

The efficacy of a once-daily dose of enalapril was compared with a thrice-daily dose of captopril in an open-label, randomized parallel group study of 27 hypertensive patients. The patients were monitored using conventional measurements of blood pressure and with 24-hour ambulatory blood pressure monitoring at baseline and after 12 weeks of therapy. The end points were 24-hour, daytime, and nighttime mean blood pressure values and the percentage of elevated systolic and diastolic measurements, reflecting the "hypertensive load." Enalapril reduced mean 24-hour systolic blood pressure by 18 mmHg and diastolic blood pressure by 11 mmHg. The comparative values for captopril were 9 mmHg and 2 mmHg, respectively. The mean daytime systolic blood pressure was reduced by 20 mmHg with enalapril versus 7 mmHg with captopril; the diastolic values were lowered by 11 mmHg with enalapril versus 4 mmHg with captopril. The mean nighttime systolic blood pressure was lowered by 16 mmHg with enalapril versus 12 mmHg with captopril; the diastolic values were reduced by 10 mmHg with enalapril and 5 mmHg with captopril. No major side effects were recorded in either group. A single daily 20-mg dose of enalapril, therefore, proved to be equipotent or superior to 75 mg of captopril administered in three divided doses.

Exercise performance and diastolic filling in essential hypertension

OBJECTIVES

To investigate the relationship between arterial blood pressure, left ventricular mass, diastolic filling and maximal exercise capacity in patients with newly diagnosed essential hypertension.

DESIGN

Asymptomatic untreated patients with office blood pressure > 140/90 mmHg were studied prospectively after exclusion of associated disease.

METHODS

Twenty consecutive white patients (14 male, 6 female; age 43 +/- 12 years) with office blood pressure 164 +/- 23/103 +/- 10 mmHg, mean 24-h ambulatory blood pressure 142 +/- 25/89 +/- 15 mmHg and normal systolic cardiac function underwent an echocardiographic examination to determine left ventricular mass and diastolic filling parameters and performed a bicycle ergometer test to determine maximal voluntary exercise capacity.

RESULTS

In single regression analysis exercise time and maximal oxygen uptake were related to sex and age. A multiple regression showed that only age was related to exercise capacity, however. On subgroup analysis of male patients between 30 and 50 years (n = 10), exercise time (659 +/- 134 s) was significantly inversely related to mean 24-h ambulatory diastolic blood pressure (92 +/- 11 mmHg) (r = -0.67; p = 0.03) and positively to diastolic filling expressed as ratio of peak early to peak atrial filling velocity (Emax/Amax ratio; 1.34 +/- 0.40) (r = 0.65; p = 0.04) or as ratio of velocity time integral (VTI) of early filling phase to VTI of atrial filling phase (VTIE/VTIA ratio; 1.94 +/- 0.72) (r = 0.02). Maximal oxygen consumption (22.3 +/- 4.1 ml/kg/min) was significantly inversely correlated with mean 24-h ambulatory diastolic blood pressure (r = -0.67; p = 0.03), mean 24-h ambulatory systolic blood pressure (147 +/- 25 mmHg) (r = -0.82; p < 0.01), left ventricular mass (312 +/- 143 g) (r = -0.86; p < 0.01), left ventricular mass index (135 +/- 41 g/m2) (r = -0.76, p = 0.01) and positively with diastolic filling expressed as Emax/Amax ratio (r = 0.71; p = 0.02) or as VTIE/VTIA ratio (r = 0.70; p = 0.02).

CONCLUSION

This study shows the important interrelation between blood pressure, cardiac mass, diastolic filling and exercise capacity. High blood pressure entrains a larger cardiac mass but slows cardiac filling and decreases exercise capacity.

Clinic blood pressure measurements and blood pressure load in the diagnosis of hypertension

We have retrospectively compared the blood pressure load derived from 24 hour ambulatory blood pressure monitoring in patients with all clinic blood pressure readings elevated with those with only some elevated pressures to establish whether clinic readings alone are good predictors of blood pressure status. Fifty-seven patients attending a district general hospital hypertension clinic who were not on anti-hypertensive treatment were selected. Between two and six clinic readings were taken over a period of 1-6 months. Forty out of 57 patients had at least one clinic diastolic blood pressure reading of < 90 mmHg and, of these, 14 (35%) had a high blood pressure load and 26 (65%) had a normal blood pressure load. Patients with all diastolic blood pressure readings > 90 mmHg totalled 17 and of these 11 (65%) had high load and six (35%) had normal load. Patients with clinic diastolic blood pressure > 90 mmHg were significantly more likely to be truly hypertensive on the basis of blood pressure load than if one or more clinic readings was below 90 mmHg (P < 0.05). Diastolic pressures have some predictive power as to the blood pressure status defined by blood pressure load, but even consistently raised diastolic pressures do not necessarily indicate hypertension. Likewise one or more clinic diastolic blood pressure < 90 mmHg does not assuredly indicate normotension. Twenty-four hour ambulatory blood pressure monitoring may have an increasingly important role in the assessment of hypertension.