Central haemodynamics and clinical outcomes: going beyond brachial blood pressure?

Central arterial pressure estimation based on two peripheral pressure measurements using one-dimensional blood flow simulation

Aortic pressure can be estimated using one-dimensional arterial flow simulations. This study demonstrates that two peripheral pressure measurements can be used to acquire the central pressure curve through the patient-specific optimization of a set of system parameters. Radial and carotid pressure measurements and parameter optimization were performed in the case of 62 patients. The two calculated aortic curves were in good agreement, Systolic and Mean Blood Pressures differed on average by 0.5 and -0.5 mmHg, respectively. Good agreement was achieved with the transfer function method as well. The effect of carotid clamping is demonstrated using one resulting patient-specific arterial network.

Central arterial pressure and patient-specific model parameter estimation based on radial pressure measurements

One-dimensional arterial flow simulations are suitable to estimate the aortic pressure from peripheral measurements in a patient-specific arterial network. This study introduces a reduction of the system parameters, and a novel calculation method to estimate the patient-specific set and the aortic curve based on radial applanation tonometry. Peripheral and aortic pressure curves were measured in patients, optimization were carried out. The aortic pressure curves were reproduced well, with an overestimation of the measured Systolic and Mean Blood Pressures on average by 0.6 and 0.5 mmHg respectively, and the Root Mean Square Difference of the curves was 3 mmHg on average.

Over-Prescription of the Imidazoline Receptor Agonists: Evidence for Restriction of the Therapeutic Indication

BACKGROUND

Major antihypertensive drug classes (but not Imidazoline Receptor Agonists) have been demonstrated to reduce cardiovascular morbidity and mortality. In 2017, Latvia and Lithuania had the highest cardiovascular mortality among the Eastern, Central, Northern, and Western Member States of the European Union (EU). Cardiovascular mortality in Estonia is much lower than in Lithuania and Latvia.

OBJECTIVE

To evaluate the consumption of Imidazoline Receptor Agonists in the Baltic States and its potential implications.

MATERIALS AND METHODS

The study included data on the sales of Imidazoline Receptor Agonists in Lithuania, Latvia, and Estonia; the marketing authorization databases of the competent authorities; the guidelines on the treatment of hypertension, and the reimbursement conditions.

RESULTS

The study showed a very high consumption of the Imidazoline Receptor Agonists in Lithuania and Latvia. From 2016 to 2019, the average consumption of Imidazoline Receptor Agonists in Lithuania was 15.5 times higher than in Estonia; in Latvia, it was 8.9 times higher than in Estonia. The guidelines recommend the use of the Imidazoline Receptors Agonists as one of the last options in hypertension therapy, but the marketing authorizations do not restrict their line of therapy.

CONCLUSIONS

Consumption of IRAs in Lithuania and Latvia is very high. The authorized use of the IRAs in the EU Member States is not in line with the guidelines on the management of arterial hypertension and therefore patients might be deprived of therapies that reduce the cardiovascular risk. The drug regulatory authorities of the EU should review the data on the safety and efficacy of the IRAs and restrict their therapeutic indications if necessary.

Pulse wave velocity is a new predictor of acute kidney injury development after off-pump coronary artery bypass grafting

Background

Brachial-ankle pulse wave velocity (baPWV) is the simple, non-invasive, gold-standard method for assessing arterial stiffness. However, baPWV has been shown to be associated with renal dyfunction, with a few reports demonstrating an association between baPWV and postoperative acute kidney injury (AKI) among surgical patients.

Methods

We retrospectively analyzed preoperative baPWV data that were prospectively collected from 164 patients who underwent off-pump coronary artery bypass grafting (CABG) between April 2013 and July 2019 (mean age: 66.2 ± 10.3 years, 29.3% females). Primarily, baPWV was investigated as an independent predictor of postoperative AKI development; secondarily, the patients were divided into high and low PWV groups according to the optimal baPWV cut-off value. Postoperative complications, mortality, and mid-term survival were compared between the two groups.

Results

AKI developed in 30 patients (18.3%). Univariate analysis showed that AKI was significantly associated with baPWV (20.2±7.3 vs. 16.2±2.8 m/s, p < 0.001), age, preoperative serum creatinine, and EuroSCORE. Multivariable logistic regression analysis revealed baPWV as independently associated with postoperative AKI even after adjustment for preoperative creatinine, old age (> 75 years), hypertension, diabetes under insulin therapy, and EuroSCORE. Moreover, area under the curve (AUC) analysis indicated that PWV can predict AKI better than preoperative creatinine levels (AUC, 0.781 [95% confidence interval, 0.688–0.874] vs. 0.680 [0.568–0.792]). The group-dividing baPWV cut-off value for AKI was 19 m/s. There were no 30-day mortality. The in-hospital mortality rates in the high and the low PWV groups were 2.2% (n = 1) and 0.8% (n = 1), respectively (p = 0.484). Midterm survival rates were not different between the two groups, but the rate of composite neurologic complication composed of stroke and delirium, was higher, and rate of mechanical ventilatory support was longer, in the high PWV group.

Conclusion

Brachial-ankle pulse wave velocity was an independent predictor of postoperative AKI following off-pump CABG, and high baPWVs may affect the composite neurologic outcome and the duration of mechanical ventilatory support.

Is Noninvasive Brachial Systolic Blood Pressure an Accurate Estimate of Central Aortic Systolic Blood Pressure?

OBJECTIVES

Noninvasive brachial systolic blood pressure (nSBP-B) usually approaches invasive central systolic blood pressure (iSBP-C) with a high correlation. Whether nSBP-B is an accurate estimate of iSBP-C remained to be investigated. Thus, this study aimed to compare the errors of nSBP-B and noninvasive central systolic blood pressure (nSBP-C) with different techniques in estimating iSBP-C.

METHODS

Simultaneous invasive high-fidelity central aortic pressure waveforms and the noninvasive left brachial pulse volume recording (PVR) waveform were recorded in a Generation group ( N = 40) and a Validation group ( N = 100). The accuracy of the noninvasive estimates of iSBP-C obtained from analysis of the calibrated PVR waveform using the generalized transfer function (GTF), pulse waveform analysis (PWA), and N-point moving average (NPMA) methods was examined in the Validation group by calculating the mean absolute error (MAE).

RESULTS

In Generation group, the MAE was 4.6±4.1mm Hg between nSBP-B and invasive brachial SBP, and 6.8±5.5mm Hg between nSBP-B and iSBP-C. In comparison, the MAE of between iSBP-C and nSBP-C with PWA, NPMA, and GTF were 5.5±4.5, 5.8±4.9, and 5.9±5.0mm Hg, respectively. In Validation group, the MAE of nSBP-B (6.9±4.6mm Hg) for estimating iSBP-C was significantly greater than that of PWA (5.0±3.4mm Hg) and NPMA (6.1±4.4mm Hg), and GTF (6.1±4.9mm Hg). The percentage of absolute band error ≤5mm Hg was 62% for nSBP-B, 69% for GTF, 83% for PWA, and 69% for NPMA.

CONCLUSIONS

The accuracy of nSBP-B was inferior to the n SBP-C measures in estimating iSBP-C.

The association between maternal blood pressures and offspring size at birth in Southeast Asian women

Background

Maternal blood pressures in pregnancy is an important determinant of offspring size at birth. However, the relationship between maternal blood pressures and offspring’s size at birth is not consistent and may vary between ethnic groups. We examined the relationship between maternal peripheral and central blood pressures and offspring size at birth in an Asian multi-ethnic cohort, and effect modifications by maternal ethnicity and obesity.

Methods

We used data from 713 participants in the Growing Up in Singapore Towards Healthy Outcomes study consisting of pregnant Chinese, Malay and Indian women recruited from two tertiary hospitals between 2009 to 2010. Peripheral systolic and diastolic blood pressures (SBP and DBP), and central SBP and pulse pressure (PP) were measured around 27 weeks of gestation. Biometric parameters at birth were collected from medical records.

Results

After adjusting for maternal and fetal covariates, each 1-SD increase (10.0 mmHg) in central SBP was inversely associated with birth weight (−40.52 g; 95% confidence interval (CI) -70.66 to −10.37), birth length (−0.19 cm; −0.36 to −0.03), head circumference (−0.12 cm; −0.23 to −0.02) and placental weight (−11.16 g; −20.85 to −1.47). A one-SD (11.1 mmHg) increase in peripheral SBP was also associated with lower birth weight (−35.56 g; −66.57 to −4.54). The inverse relations between other blood pressure measures and offspring size at birth were observed but not statistically significant. Higher peripheral SBP and DBP and central SBP were associated with increased odds of low birth weight (defined as weight <2500 g) and small for gestational age (defined as <10^th percentile for gestational age adjusted birth weight). Maternal adiposity modified these associations, with stronger inverse associations in normal weight women. No significant interactions were found with ethnicity.

Conclusions

Higher second-trimester peripheral and central systolic pressures were associated with smaller offspring size at birth, particularly in normal weight women. Findings from this study reinforces the clinical relevance of antenatal blood pressure monitoring.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-014-0403-1) contains supplementary material, which is available to authorized users.

Assessment of central blood pressure in patients with type 2 diabetes: a comparison between SphygmoCor and invasively measured values

BACKGROUND

The SphygmoCor is used for noninvasive assessment of ascending aortic blood pressure (BP). However, the validity of the SphygmoCor transfer function has not been tested in an exclusively type 2 diabetic patient sample. Calibration with systolic (SBP) and diastolic (DBP) brachial BP has previously been associated with substantial imprecision of central BP estimates. We hypothesized that different noninvasive calibration strategies might improve the accuracy of the estimated ascending aortic BPs.

METHODS

In 34 patients with type 2 diabetes we estimated ascending aortic SBP and DBP using the SphygmoCor device and compared these data with invasively recorded data. The validity of the transfer function was assessed by calibrating with invasively recorded DBP and mean BP (MBP). The influence of noninvasive calibration strategies was assessed by calibrating with brachial oscillometric SBP+DBP vs. DBP+MBP using a form factor (ff) of 0.33 and 0.40, respectively.

RESULTS

When calibrating with invasive BP, the difference between estimated and invasively measured ascending aortic SBP and DBP was -2.3±5.6/1.0±0.9 mm Hg. When calibrating with oscillometric brachial BPs, the differences were -9.6±8.1/14.1±6.2 mm Hg (calibration with SBP and DBP), -8.3±11.7/13.9±6.1 mm Hg (DBP and MBP; ff = 0.33), and 1.9±12.2/14.1±6.2 mm Hg (DBP and MBP; ff = 0.40), respectively. Calibration with the average of 3 brachial BPs did not improve accuracy.

CONCLUSIONS

The SphygmoCor transfer function seems valid in patients with type 2 diabetes. Noninvasive calibration with DBP and MBP (ff = 0.40) enables accurate estimation of mean ascending aortic SBP at the group level. However, the wide limits of agreement indicate limited accuracy in the individual patient.

CLINICAL TRIALS REGISTRATION

Clinical Trials No. NCT01538290.

Effects of red wine on established markers of arterial structure and function in human studies: current knowledge and future research directions

Evidence from observational studies suggests that mild-to-moderate consumption of red wine is associated with reduced cardiovascular morbidity and mortality. Various individual chemical components of red wine also show salutary effects on vascular homeostasis, that is, enhanced endothelial function and arterial distensibility, both in vitro and in animal studies. However, testing the beneficial potential of red wine in primary and secondary cardiovascular prevention on established surrogate cardiovascular markers requires further study with longer term intervention trials. This report reviews and critically appraises the published evidence for the effects of red wine on endothelium-dependent vasodilation, arterial stiffness and arterial wave reflections in healthy subjects and in patients with cardiovascular disease. Suggestions for future research directions are also provided.

Cardiovascular and metabolic risk profile in young people at familial risk of depression

BACKGROUND

Depression is associated with increased risk of several general medical conditions, including diabetes and cardiovascular disease. The nature of the association is complex and may involve bidirectional causation or a common pathophysiology.

AIMS

To determine whether young people without depression but at increased familial risk have altered metabolic and blood pressure markers relative to matched controls.

METHOD

We studied young people (n = 85), who had a parent with depression but no personal history of depressive illness (FH+) and healthy controls (n = 69). Cardiovascular risk profile was assessed by a fasting blood sample to measure insulin, glucose, lipids and high-sensitivity C-reactive protein (CRP) and blood pressure was measured centrally and peripherally. Arterial stiffness and waking cortisol concentration were also measured.

RESULTS

Compared with controls, the FH+ group demonstrated increased peripheral and central systolic blood pressure, increased arterial stiffness and diminished insulin sensitivity but they did not differ from controls in measures of lipids, CRP or waking cortisol.

CONCLUSIONS

Our data suggest that young people at increased familial risk of depression show evidence of altered cardiovascular risk profile in young adulthood even in the absence of depressive symptoms. It is possible therefore that vulnerability to conditions such as hypertension and diabetes may precede the onset of major depression and may share common risk factors.

A cohort evaluation on arterial stiffness and hypertensive disorders in pregnancy

BACKGROUND

Hypertensive disorders in pregnancy are associated with systemic endothelial dysfunction leading to impaired physiological vasodilation. Recent evidence has shown central aortic pressures obtained through pulse wave analysis, at less than 14 weeks of gestation, to be predictive of pre-eclampsia. In light of this, we aimed to evaluate the role of central aortic stiffness in the prediction and discrimination of hypertensive disorders in pregnancy.

METHODS

A cohort study of women with viable, singleton pregnancies at less than 14 weeks of amenorrhoea, and without multiple pregnancies, autoimmune or renal disease, diagnosed with aneuploidy or fetal anomaly will be recruited from a single maternity hospital and followed up till delivery and puerperium. A targeted sample size of 1000 eligible pregnant women will be enrolled into the study from antenatal clinics. Main exposure under study is central aortic pulse pressure using radial pulse wave recording, and the outcomes under follow-up are gestational hypertension and pre-eclampsia. Other measures include lifestyle factors such as smoking, physical exercise, psychometric evaluations, vasoactive factors, uterine artery pulsatility index, height and weight measurements. These measures will be repeated over 4 antenatal visits at 11-14, 18-22, 28-32 and above 34 weeks of gestation. Double data entry will be performed on Microsoft Access, and analysis of data will include the use of random effect models and receiver operating characteristic curves on Stata 11.2.

DISCUSSION

The proposed study design will enable a longitudinal evaluation of the central aortic pressure changes as a marker for vascular compliance during pregnancy. As measures are repeated over time, the timing and severity of changes are detectable, and findings may yield important information on how aberrant vascular responses occur and its role in the early detection and prediction of hypertensive disorders.

Progression of central pulse pressure over 1 decade of aging and its reversal by nitroglycerin a twin study

OBJECTIVES

The goal of this study was to examine the progression of central arterial pulse pressure (cPP) in women and the degree to which this can be reversed by nitrovasodilation.

BACKGROUND

cPP can be partitioned into height of the first systolic shoulder (P1), generated by a forward pressure wave and related to arterial stiffness, and augmentation pressure (AP), thought to be influenced by pressure wave reflection from muscular arteries and/or aortic reservoir.

METHODS

Using a longitudinal cohort design, cPP, P1, and AP were estimated (using the SphygmoCor System [AtCor Medical Pty Ltd., West Ryde, Australia]) in 411 female twins over a mean follow-up of 10.8 years. In a subsample (n = 42), cPP, arterial stiffness (using pulse wave velocity [PWV]) and arterial diameters (using ultrasonography) were measured before and after nitroglycerin administration (400 μg s/l).

RESULTS

cPP increased more than peripheral pulse pressure (10.3 and 9.2 mm Hg, respectively; p < 0.0001). In women <60 years of age at follow-up, AP contributed more to the increase in cPP than did P1 (increases of 6.5 ± 6.4 mm Hg and 4.2 ± 7.8 mm Hg, respectively). P1 was significantly positively correlated to PWV (p < 0.0001); AP was correlated to aorto-femoral tapering (p < 0.0001) but not PWV. Nitroglycerin reduced cPP by 10.0 ± 6.0 mm Hg (p < 0.0001), equivalent to a decade of aging. The reduction in cPP was entirely explained by a decrease in AP, with no significant change in P1 or PWV but an increase in large artery diameters of 4% to 18% (p < 0.0001).

CONCLUSIONS

Age-related widening of cPP is driven in large part by an increase in AP, which can be reversed by selective dilation of muscular arteries, independent of PWV.

Aging-associated cardiovascular changes and their relationship to heart failure

Aging represents a convergence of declining cardioprotective systems and increasing disease processes that is fertile ground for the development of heart failure. Fifty percent of all heart failure diagnoses and 90% of all heart failure deaths occur in individuals older than 70. This article discusses the microscopic and macroscopic changes in cardiovascular structure, function, protective systems, and disease associated with aging. In addition to outlining important clinical considerations and conditions in older persons, the link between normal aging and the elevated risk for development of stage B heart failure is explained and potential therapeutic pathways are highlighted.

Central blood pressure and chronic kidney disease progression

Hypertension, diabetes, and proteinuria are well-recognized risk factors for progressive kidney function loss. However, despite excellent antihypertensive and antidiabetic drug therapies, which also often lower urinary protein excretion, there remains a significant reservoir of patients with chronic kidney disease who are at high risk for progression to end-stage kidney disease. This has led to the search for less traditional cardiovascular risk factors that will help stratify patients at risk for more rapid kidney disease progression. Among these are noninvasive estimates of vascular structure and function. Arterial stiffness, manifested by the pulse wave velocity in the aorta, has been established in a number of studies as a significant risk factor for kidney disease progression and cardiovascular endpoints. Much less well studied in chronic kidney disease are measures of central arterial pressures. In this paper we cover the physiology behind the generation of the central pulse wave contour and the studies available using these approaches and conclude with some speculations on the rationale for why measurements of central pressure may be informative for the study of chronic kidney disease progression.