Search

Background: Central systolic blood pressure (cSBP) can be derived by the general transfer function of the radial pressure wave, as used in the SphygmoCor device, or by regression equation from directly measured late systolic shoulder of the radial pressure wave (pSBP2), as used in the Omron HEM-9000AI device. The aim of this study was to compare the SphygmoCor estimates of cSBP with 2 estimates of cSBP provided by the Omron HEM-9000AI (cSBP, pSBP2) in a large cohort of the white population., Methods: In 391 patients aged 52.3±13.5 years (46% men) from the Czech post-MONICA Study, cSBP was measured using the SphygmoCor and Omron HEM-9000AI devices in random order., Results: Omron cSBP and pSBP2 were perfectly correlated (r = 1.0; P < 0.0001). There was a strong correlation (r = 0.97; P < 0.0001) between Omron and SphygmoCor cSBP estimates, but Omron estimate was 13.1±4.7mm Hg higher than SphygmoCor cSBP. On the other hand, Omron pSBP2 strongly correlated with SphygmoCor cSBP (r = 0.97; P < 0.0001) and was 1.7±4.2mm Hg lower than SphygmoCor cSBP. In multivariable analysis, anthropometric and cardiovascular risk factors explained only 10% of the variance of the cSBP difference between devices while explaining 52% of the systolic blood pressure amplification variance., Conclusions: Estimation of cSBP based on the late systolic shoulder of the radial wave provides a comparable accuracy with the validated general transfer function. When comparing Omron HEM-9000AI and SphygmoCor estimates of cSBP, Omron pSBP2 should be used. The difference between both devices in cSBP may be explained by differences in calibration.

Background: Average real variability (ARV) is a recently proposed index for short-term blood pressure (BP) variability. We aimed to determine the minimum number of BP readings required to compute ARV without loss of prognostic information., Methods: ARV was calculated from a discovery dataset that included 24-hour ambulatory BP measurements for 1,254 residents (mean age = 56.6 years; 43.5% women) of Copenhagen, Denmark. Concordance between ARV from full (≥80 BP readings) and randomly reduced 24-hour BP recordings was examined, as was prognostic accuracy. A test dataset that included 5,353 subjects (mean age = 54.0 years; 45.6% women) with at least 48 BP measurements from 11 randomly recruited population cohorts was used to validate the results., Results: In the discovery dataset, a minimum of 48 BP readings allowed an accurate assessment of the association between cardiovascular risk and ARV. In the test dataset, over 10.2 years (median), 806 participants died (335 cardiovascular deaths, 206 cardiac deaths) and 696 experienced a major fatal or nonfatal cardiovascular event. Standardized multivariable-adjusted hazard ratios (HRs) were computed for associations between outcome and BP variability. Higher diastolic ARV in 24-hour ambulatory BP recordings predicted (P < 0.01) total (HR = 1.12), cardiovascular (HR = 1.19), and cardiac (HR = 1.19) mortality and fatal combined with nonfatal cerebrovascular events (HR = 1.16). Higher systolic ARV in 24-hour ambulatory BP recordings predicted (P < 0.01) total (HR = 1.12), cardiovascular (HR = 1.17), and cardiac (HR = 1.24) mortality., Conclusions: Forty-eight BP readings over 24 hours were observed to be adequate to compute ARV without meaningful loss of prognostic information.

Although distinguishing features of masked hypertension in diabetics are well known, the significance of antihypertensive treatment on clinical practice decisions has not been fully explored. We analyzed 9691 subjects from the population-based 11-country International Database on Ambulatory Blood Pressure in Relation to Cardiovascular Outcomes. Prevalence of masked hypertension in untreated normotensive participants was higher (P<0.0001) among 229 diabetics (29.3%, n=67) than among 5486 nondiabetics (18.8%, n=1031). Over a median of 11.0 years of follow-up, the adjusted risk for a composite cardiovascular end point in untreated diabetic-masked hypertensives tended to be higher than in normotensives (hazard rate [HR], 1.96; 95% confidence interval [CI], 0.97-3.97; P=0.059), similar to untreated stage 1 hypertensives (HR, 1.07; CI, 0.58-1.98; P=0.82), but less than stage 2 hypertensives (HR, 0.53; CI, 0.29-0.99; P=0.048). In contrast, cardiovascular risk was not significantly different in antihypertensive-treated diabetic-masked hypertensives, as compared with the normotensive comparator group (HR, 1.13; CI, 0.54-2.35; P=0.75), stage 1 hypertensives (HR, 0.91; CI, 0.49-1.69; P=0.76), and stage 2 hypertensives (HR, 0.65; CI, 0.35-1.20; P=0.17). In the untreated diabetic-masked hypertensive population, mean conventional systolic/diastolic blood pressure was 129.2 ± 8.0/76.0 ± 7.3 mm Hg, and mean daytime systolic/diastolic blood pressure 141.5 ± 9.1/83.7 ± 6.5 mm Hg. In conclusion, masked hypertension occurred in 29% of untreated diabetics, had comparable cardiovascular risk as stage 1 hypertension, and would require considerable reduction in conventional blood pressure to reach daytime ambulatory treatment goal. Importantly, many hypertensive diabetics when receiving antihypertensive therapy can present with normalized conventional and elevated ambulatory blood pressure that mimics masked hypertension.

Background: The double product (DP), consisting of the systolic blood pressure (SBP) multiplied by the pulse rate (PR), is an index of myocardial oxygen consumption, but its prognostic value in the general population remains unknown., Methods: We recorded health outcomes in 9,937 subjects (median age, 53.2 years; 47.3% women) randomly recruited from 11 populations and enrolled in the International Database on Ambulatory blood pressure in relation to Cardiovascular Outcomes (IDACO) study. We obtained the SBP, PR, and DP for these subjects as determined through 24-hour ambulatory monitoring., Results: Over a median period of 11.0 years, 1,388 of the 9,937 study subjects died, of whom 536 and 794, respectively, died of cardiovascular (CV) and non-CV causes, and a further 1,161, 658, 494, and 465 subjects, respectively, experienced a CV, cardiac, coronary, or cerebrovascular event. In multivariate-adjusted Cox models, not including SBP and PR, DP predicted total, CV, and non-CV mortality (standardized hazard ratio [HR], ≥ 1.10; P ≤ 0.02), and all CV, cardiac, coronary, and stroke events (HR, ≥ 1.21; P < 0.0001). For CV mortality (HR, 1.34 vs. 1.30; P = 0.71) and coronary events (1.28 vs. 1.21; P = 0.26), SBP and the DP were equally predictive. As compared with DP, SBP was a stronger predictor of all CV events (1.39 vs. 1.27; P = 0.002) and stroke (1.61 vs. 1.36; P < 0.0001), and a slightly stronger predictor of cardiac events (1.32 vs. 1.22; P = 0.06). In fully adjusted models, including both SBP and PR, the predictive value of DP disappeared for fatal endpoints (P ≥ 0.07), coronary events (P = 0.06), and stroke (P = 0.12), or DP was even inversely associated with the risk of all CV and cardiac events (both P ≤ 0.01)., Conclusion: In the general population, we did not observe DP to add to risk stratification over and beyond SBP and PR.

No previous study addressed whether in the general population estimated glomerular filtration rate (eGFR [Chronic Kidney Disease Epidemiology Collaboration formula]) adds to the prediction of cardiovascular outcome over and beyond ambulatory blood pressure. We recorded health outcomes in 5322 subjects (median age, 51.8 years; 43.1% women) randomly recruited from 11 populations, who had baseline measurements of 24-hour ambulatory blood pressure (ABP(24)) and eGFR. We computed hazard ratios using multivariable-adjusted Cox regression. Median follow-up was 9.3 years. In fully adjusted models, which included both ABP(24) and eGFR, ABP(24) predicted (P≤0.008) both total (513 deaths) and cardiovascular (206) mortality; eGFR only predicted cardiovascular mortality (P=0.012). Furthermore, ABP(24) predicted (P≤0.0056) fatal combined with nonfatal events as a result of all cardiovascular causes (555 events), cardiac disease (335 events), or stroke (218 events), whereas eGFR only predicted the composite cardiovascular end point and stroke (P≤0.035). The interaction terms between ABP(24) and eGFR were all nonsignificant (P≥0.082). For cardiovascular mortality, the composite cardiovascular end point, and stroke, ABP(24) added 0.35%, 1.17%, and 1.00% to the risk already explained by cohort, sex, age, body mass index, smoking and drinking, previous cardiovascular disease, diabetes mellitus, and antihypertensive drug treatment. Adding eGFR explained an additional 0.13%, 0.09%, and 0.14%, respectively. Sensitivity analyses stratified for ethnicity, sex, and the presence of hypertension or chronic kidney disease (eGFR <60 mL/min per 1.73 m(2)) were confirmatory. In conclusion, in the general population, eGFR predicts fewer end points than ABP(24). Relative to ABP(24), eGFR is as an additive, not a multiplicative, risk factor and refines risk stratification 2- to 14-fold less.

Background: Ankle brachial index (ABI) has been increasingly used in general practice to identify individuals with low ABI at high cardiovascular risk. However, there has been no consensus on the clinical significance of high ABI. The aim of our study was to compare aortic stiffness as a marker of cardiovascular risk in individuals with low (<1.0), normal (1.0-1.4), and high ABI (>1.4)., Methods: A total of 911 individuals from the Czech post-MONICA study (a randomly selected 1% representative population sample, aged 54 ± 13.5 years, 47% of men) were examined. ABI was measured using a handheld Doppler and aortic pulse wave velocity (aPWV) using the Sphygmocor device., Results: Of the 911 individuals, 28 (3.1%) had low ABI and 23 (2.5%) high ABI. There was a U-shaped association between aPWV and ABI. aPWV was significantly higher in individuals with low and high ABI compared with the normal ABI group (11.1 ± 2.8, 8.3 ± 2.3, p < 0.001; 10.8 ± 2.5, 8.3 ± 2.3 m/s, p < 0.001, respectively). In a model adjusted for age, sex, systolic, diastolic, mean blood pressure and examiner, aPWV remained increased in both extreme ABI groups compared with the normal ABI group. In logistic regression analysis, aPWV together with glucose level, male sex, and a history of deep venous thrombosis were independent predictors of high ABI, while cholesterol was not., Conclusion: This is the first study showing increased aortic stiffness in individuals with high ABI, presumably responsible for increased left ventricular mass described previously in this group. These findings suggest increased cardiovascular risk of high ABI individuals.

Objectives: The International Database on Ambulatory Blood Pressure Monitoring (1993-1994) lacked a prospective dimension. We are constructing a new resource of longitudinal population studies to investigate with great precision to what extent the ambulatory blood pressure improves risk stratification., Methods: The acronym IDACO refers to the new International Database of Ambulatory blood pressure in relation to Cardiovascular Outcome. Eligible studies are population based, have fatal as well as nonfatal outcomes available for analysis, comply with ethical standards, and have been previously published in peer-reviewed journals. In a meta-analysis based on individual patient data, composite and cause-specific cardiovascular events will be related to various indexes derived by ambulatory blood pressure monitoring. The analyses will be stratified by cohort and adjusted for the conventional blood pressure and other cardiovascular risk factors., Results: To date, the international database includes 7609 patients from four cohorts recruited in Copenhagen, Denmark (n=2311), Noorderkempen, Belgium (n=2542), Ohasama, Japan (n=1535), and Uppsala, Sweden (n=1221). In these four cohorts, during a total of 69,295 person-years of follow-up (median 9.3 years), 1026 patients died and 929 participants experienced a fatal or nonfatal cardiovascular event. Follow-up in five other eligible cohorts, involving a total of 4027 participants, is still in progress. We expect that this follow-up will be completed by the end of 2007., Conclusion: The international database of ambulatory blood pressure in relation to cardiovascular outcome will provide a shared resource to investigate risk stratification by ambulatory blood pressure monitoring to an extent not possible in any earlier individual study.