Interaction between pulse wave velocity, augmentation index, pulse pressure and left ventricular function in chronic heart failure

Examining arterial pulsation to identify and risk-stratify heart failure subjects with deep neural network

Hemodynamic parameters derived from pulse wave analysis have been shown to predict long-term outcomes in patients with heart failure (HF). Here we aimed to develop a deep-learning based algorithm that incorporates pressure waveforms for the identification and risk stratification of patients with HF. The first study, with a case-control study design to address data imbalance issue, included 431 subjects with HF exhibiting typical symptoms and 1545 control participants with no history of HF (non-HF). Carotid pressure waveforms were obtained from all the participants using applanation tonometry. The HF score, representing the probability of HF, was derived from a one-dimensional deep neural network (DNN) model trained with characteristics of the normalized carotid pressure waveform. In the second study of HF patients, we constructed a Cox regression model with 83 candidate clinical variables along with the HF score to predict the risk of all-cause mortality along with rehospitalization. To identify subjects using the HF score, the sensitivity, specificity, accuracy, F1 score, and area under receiver operating characteristic curve were 0.867, 0.851, 0.874, 0.878, and 0.93, respectively, from the hold-out cross-validation of the DNN, which was better than other machine learning models, including logistic regression, support vector machine, and random forest. With a median follow-up of 5.8 years, the multivariable Cox model using the HF score and other clinical variables outperformed the other HF risk prediction models with concordance index of 0.71, in which only the HF score and five clinical variables were independent significant predictors (p < 0.05), including age, history of percutaneous coronary intervention, concentration of sodium in the emergency room, N-terminal pro-brain natriuretic peptide, and hemoglobin. Our study demonstrated the diagnostic and prognostic utility of arterial waveforms in subjects with HF using a DNN model. Pulse wave contains valuable information that can benefit the clinical care of patients with HF.

Novel Pulse Waveform Index by Ambulatory Blood Pressure Monitoring and Cardiac Function: A Pilot Study

Background

A simple ambulatory measure of cardiac function could be helpful for monitoring heart failure patients.

Objectives

The purpose of this paper was to determine whether a novel pulse waveform analysis using data obtained by our developed multisensor-ambulatory blood pressure monitoring (ABPM) device, the 'Sf/Am' ratio, is associated with echocardiographic left ventricular ejection fraction (LVEF).

Methods

Multisensor-ABPM was conducted twice at baseline in 20 heart failure (HF) patients with HF-reduced LVEF or HF-preserved LVEF (median age 66 years, male 65%) and over a 6- to 12-month follow-up after patient-tailored treatment. We assessed the changes in the pulse waveform index Sf/Am and LVEF that occurred between the baseline and follow-up. The Sf/Am consists of the area of the ejection part in the square forward wave (Sf) and the amplitude of the measured wave (Am). We divided the patients into the recovered (n = 11) and not-recovered (n = 9) groups defined by a ≥10% increase in LVEF.

Results

Although the ambulatory BP levels and variabilities did not change in either group, the Sf/Am increased significantly in the recovered group (baseline 21.4 ± 4.5; follow-up, 25.6 ± 3.7, P = 0.004). The not-recovered group showed no difference between the baseline and follow-up. The follow-up/baseline Sf/Am ratio was significantly associated with the LVEF ratio (r = 0.469, P = 0.037). The Sf/Am was significantly correlated with the LVEF in overall measurements (n = 40, r = 0.491, P = 0.001).

Conclusions

These results demonstrated that a novel noninvasive pulse waveform index, the Sf/Am measured by multisensor-ABPM is associated with LVEF. The Sf/Am may be useful for estimating cardiac function.

Children with inflammatory bowel disease already have an altered arterial pulse wave

Adults with inflammatory bowel disease (IBD) have an increased risk for vascular events. This study aims to evaluate arterial parameters in paediatric IBD. Carotid intima-media thickness (CIMT) was measured by ultrasound, and Arteriograph was used to assess aortic pulse wave velocity (PWVao), brachial and aortic augmentation indexes (AixBrach, AixAo), central systolic blood pressure (SBPao), and heart rate (HR). A total of 161 children were included; 55 (34%) children with newly diagnosed IBD (median age 14.35 (11.88-16.31) years, 53% males), 53(33%) in remission (median age 15.62 (13.46-16.70) years, 66% males), and 53 (33%) controls (median age 14.09 (11.18-14.09) years, 55% males) were recruited into a case-control study. Compared to controls, patients with active disease and those in clinical remission had significantly lower AixBrach and AixAo (P < 0.001, P = 0.009; P < 0.001, P = 0.003). PWVao and CIMT were still normal. HR was higher in both IBD groups than in controls (P < 0.001; P = 0.006). HR positively correlated with disease duration (P = 0.001). In the ordinary least squares regression models, anti-tumour necrosis factor (TNF) α treatment predicted lower peripheral and central systolic blood pressures, in contrast to aminosalicylates and methotrexate. Aminosalicylate treatment predicted increased HR.  Conclusion: Children with IBD have an increased heart rate, a lower augmentation index and, therefore, an altered pulse waveform. In paediatric IBD, arterial stiffness and CIMT are still normal, indicating the potential for adequate IBD treatment to preserve arterial health. What is Known: • Adult patients with inflammatory bowel disease (IBD) have increased carotid intima-media thickness and arterial stiffness, which positively correlates with cardiovascular risk and predicts mortality. Adequate treatment, especially anti-tumour necrosis factor (TNF) α medications, lower these risks. • Children with IBD have impaired endothelial function and reduced heart rate (HR) variability. What is New: • Children with IBD have impaired endothelial function and reduced heart rate (HR) variability. • Anti-TNFα treatment in children and adolescents with IBD lowers systolic pressure, whereas methotrexate and aminosalicylates have the opposite effect. Amiynosalyiciylate treatment also increases HR.

Augmentation Index in Patients with Thoracic Aortic Aneurysm: A Matched Case-Control Study

Thoracic aortic aneurysms (TAA) may be associated with complications such as rupture and dissection, which can lead to a fatal outcome. Increased central arterial stiffness has been proposed to be present in patients with TAA compared to unmatched controls. We aimed to assess whether wall properties in patients with TAA are also altered when compared to a matched control group. Applanation tonometry was performed in 74 adults with TAA and 74 sex, age, weight, height, and left ventricular ejection fraction matched controls. Subsequently analysis of the pulse wave was done using the SphygmoCor System. For comparing the two groups, AIx was adjusted to a heart rate of 75/min (AIx@75). 148 1-to-1 matched participants were included in the final model. There was no significant difference in the Alx@75 between the TAA group and the matched control group [mean (SD) of 24.7 (11.2) % and 22.8 (11.2) %, p = 0.240]. Adjusted for known cardiovascular risk factors, there was no association between TAA and AIx@75. Patients with TAA showed comparable arterial wall properties to cardiovascular risk factor matched controls. Since higher arterial stiffness is associated with TAA progression, it remains to be investigated if increased central arterial stiffness is a relevant factor of TAA emergence.

Twenty-Four-Hour Pulsatile Hemodynamics Predict Brachial Blood Pressure Response to Renal Denervation in the SPYRAL HTN-OFF MED Trial

Renal denervation (RDN) lowers blood pressure (BP), but BP response is variable in individual patients. We investigated whether measures of pulsatile hemodynamics, obtained during 24-hour ambulatory BP monitoring, predict BP drop following RDN.

Association of arterial stiffness and heart failure with preserved ejection fraction in the elderly population - results from the CARLA study

Arterial stiffness has been suspected as a cause of left ventricular diastolic dysfunction and may thereby contribute to the development of heart failure with preserved ejection fraction (HFpEF). However, this association is derived from a small number of studies and application of outdated criteria to diagnose HFpEF. This study aimed to investigate the association of arterial stiffness measured by the augmentation index (AIx) and criteria for diagnosing HFpEF according to the recommended HFA-PEFF score. Our analysis based on data from the first follow-up of the CARdiovascular Disease, Living and Ageing in Halle study. The current analysis included participants with available information about comorbidities and risk factors for HFpEF, parameters for calculation of the HFA-PEFF and noninvasive AIx estimated by applanation tonometry. The association of AIx and HFA-PEFF was investigated through descriptive and inductive statistics. A total of 767 participants were included in the analysis. AIx was associated with E/e', left ventricular wall thickness (LVWT), relative wall thickness, left ventricular mass index (LVMI) and NT-proBNP but not with e' or left atrial volume index. However, after adjustment for confounders, only LVMI and LVWT remained associated with AIx. Males with a high AIx had a 3.2-fold higher likelihood of HFpEF than those with a low AIx. In contrast, that association was not present in females. In summary, AIx is associated with the morphological domain of the HFA-PEFF score represented by LVMI and LVWT. Higher values of AIx are associated with a higher likelihood for HFpEF in elderly males but not in females.

Inadequacy of Augmentation Index for Monitoring Arterial Stiffness: Comparison with Arterial Compliance and Other Hemodynamic Variables

PURPOSE

Augmentation Index (AI_x) is used clinically for monitoring both wave reflections and arterial stiffness, which when increased is a risk factor of cardiovascular mortality and morbidity. We hypothesize that AI_x is not solely related to vascular stiffness as described by arterial compliance and other hemodynamic parameters since AI_x underestimates wave reflections.

METHODS

Aortic pressure and flow datasets (n = 42) from mongrel dogs were obtained from our experiments and Mendeley Data under various conditions. Arterial compliances based on the Windkessel model (C_t), the stroke volume (SV) to pulse pressure (PP) ratio (C_v = SV/PP), and at inflection pressure point (C_Pi) were computed. Other relevant hemodynamic factors are also computed.

RESULTS

AI_x was poorly associated with arterial stiffness calculated from C_t (r = 0.299, p = 0.058) or C_Pi (r = 0.203, p = 0.203), even when adjusted for heart rates. C_t and C_v were monotonically associated. Alterations in inflection pressure (P_i) did not follow the changes in pulse pressure (PP) (r = 0.475, p = 0.002), and P_i was quantitatively similar to systolic pressure (r = 0.940, p < 0.001).

CONCLUSION

AI_x is neither linearly correlated with arterial stiffness, nor with arterial compliance and several cardiac and arterial parameters have to be considered when AI_x is calculated.

Pulse sharpness as a quantitative index of vascular aging

The aim of this study was to develop a robust algorithm to quantify pulse sharpness that can complement the limitations of radial augmentation index (rAIx) and explore the role of this quantitative sharpness index in reflecting vascular aging or arterial stiffness. The pulse sharpness index (PSI) was developed by combining the end point angle and virtual height, and 528 radial pulses were analyzed. The PSI could be uniformly applied to various waveform morphologies, even those with no or vague tidal waves, unlike the rAIx. Significant sex differences were identified in the rAIx and PSI (P < 0.01 for both), and significant age-dependent decreases in the PSI were observed (P < 0.01). In addition, the PSI and age were correlated (r = - 0.550) at least as strong as the rAIx and age (r = 0.532), and the PSI had a significant negative correlation with arterial stiffness (r = - 0.700). Furthermore, the multiple linear regression model for arterial stiffness using the PSI, age, sex and heart rate showed the excellent performance (cross-validated R2 = 0.701), and the PSI was found to have the greatest influence on arterial stiffness. This study confirmed that the PSI could be a quantitative index of vascular aging and has potential for use in inferring arterial stiffness with an advantage over the rAIx.

Relationship of end-tidal oxygen partial pressure to the determinants of anaerobic threshold in post-myocardial infarction patients

The anaerobic threshold (AT), obtained during cardiopulmonary exercise testing (CPET), is an important prognostic measure and can be used to develop an exercise prescription in patients after a myocardial infarction (post-MI). The purpose of this study was to examine the central and peripheral determinants of AT in post-MI patients end-tidal oxygen partial pressure (PETO₂) measures. We performed cardiopulmonary exercise testing (CPET) on 148 consecutively enrolled post-MI patients to determine PETO₂ measured at the AT (AT PETO₂) and ΔPETO₂ (difference between resting PETO₂ and AT PETO₂). We subsequently investigated the relationship between these measures of PETO₂ and the individual AT for each patient. Multivariate linear regression analysis indicated that AT PETO₂ and ΔPETO₂ were independently and significantly associated with the AT (β = -0.344, p < 0.001 and β = 0.228, p < 0.001, respectively). Furthermore, the independent factors of AT PETO₂ were left ventricular ejection fraction (p = 0.005), resting ventilatory equivalent for carbon dioxide (p = 0.002), and resting dead-space gas volume to tidal volume ratio (p < 0.001). However, the independent factors for ΔPETO₂ were history of diabetes (p = 0.047), estimated glomerular filtration rate (p = 0.001), and resting systolic blood pressure (p = 0.017). These findings suggested that AT PETO₂ was associated with central determinants; whereas, and ΔPETO₂ was associated with peripheral determinants, The AT PETO₂ and ΔPETO₂ provide variable insight regarding the cause of exercise intolerance and can be used to determine appropriate therapies.

Carotid Pulse Wave Analysis: Future Direction of Hemodynamic and Cardiovascular Risk Assessment

Evaluation of the hemodynamic function of the cardiovascular system via measurement of the mechanical properties of the large arteries may provide a substantial improvement over present techniques. Practitioners are familiar with the problem of low reproducibility of conventional sphygmomanometry, which exhibits reasonable accuracy but low precision owing to its marked variability over time and in different circumstances (e.g., the white coat effect). Arterial wall stiffness is a consequence of atherosclerosis developing over time; thus, it has little short-term variability and is thus preferable to be used as a prognostic marker. In particular, arterial stiffness can be evaluated at the carotid artery using noninvasive approaches based on wearable sensor technologies for pulse wave analysis. These enable the assessment of central pressures and pulse waveform parameters that are expected to replace peripheral blood pressure measurement using the inflatable cuff. In this study, we discuss this simple and inexpensive technique, which has been shown to be reliable with the clinical and epidemiological evidence for its use as a biomarker of cardiovascular risk.

Management of low blood pressure in ambulatory heart failure with reduced ejection fraction patients

Low blood pressure is common in patients with heart failure and reduced ejection fraction (HFrEF). While spontaneous hypotension predicts risk in HFrEF, there is only limited evidence regarding the relationship between hypotension observed during heart failure (HF) drug titration and outcome. Nevertheless, hypotension (especially orthostatic hypotension) is an important factor limiting the titration of HFrEF treatments in routine practice. In patients with signs of shock and/or severe congestion, hospitalization is advised. However, in the very frequent cases of non-severe and asymptomatic hypotension observed while taking drugs with a class I indication in HFrEF, European and US guidelines recommend maintaining the same drug dosage. In instances of symptomatic or severe persistent hypotension (systolic blood pressure < 90 mmHg), it is recommended to first decrease blood pressure reducing drugs not indicated in HFrEF as well as the loop diuretic dose in the absence of associated signs of congestion. Unless the management of hypotension appears urgent, a HF specialist should then be sought rather than stopping or decreasing drugs with a class I indication in HFrEF. If symptoms or severe hypotension persist, no recommendations exist. Our HF group reviewed available evidence and proposes certain steps to follow in such situations in order to improve the pharmacological management of these patients.

Thoracic Aortic Aneurysm Growth in Bicuspid Aortic Valve Patients: Role of Aortic Stiffness and Pulsatile Hemodynamics

Background

Bicuspid aortic valve (BAV) is the most common congenital cardiac abnormality. A thoracic aortic aneurysm (TAA) is present in ≈50% of BAV patients, who also have an 8‐fold higher risk of aortic dissection than the general population. Because the health of the aorta is directly reflected in its stiffness and pulsatile hemodynamics, we hypothesized that measures of aortic stiffness and arterial load would be associated with TAA growth in BAV.

Methods and Results

Twenty‐nine unoperated participants with TAA due to BAV who had serial imaging were recruited. Aortic stiffness and steady and pulsatile arterial load were evaluated with validated methods that integrate arterial tonometry with echocardiography. TAA growth was assessed retrospectively based on available imaging, blinded to hemodynamic status. Multivariable linear regression assessed associations of aortic stiffness and hemodynamic variables with TAA growth, adjusting for potential confounders. Overall, 66% of participants were men. Mean±SD for age, baseline aneurysm size, growth rate, and follow‐up time were 57.2±8.3 years, 46.9±3.6 mm, 0.75±0.81 mm/y, and 2.9±3.3 years, respectively. We found that greater aortic stiffness (β±SE for carotid‐femoral pulse wave velocity: 0.30±0.13. P=0.03) and aortic characteristic impedance (β±SE: 0.46±0.18, P=0.02), as well as lower total arterial and proximal aortic compliance (β±SE: −0.44±0.21, P=0.05, and −0.63±0.16, P=0.001, respectively) were independently associated with faster aneurysm growth.

Conclusions

In patients with TAA due to BAV, measures of greater aortic stiffness and pulsatile arterial load indicate an association with accelerated aneurysm expansion. Assessing arterial hemodynamics may be useful for risk stratification and disease monitoring in TAA patients with BAV.

Clinical significance of brachial-ankle pulse-wave velocity in patients with heart failure with preserved left ventricular ejection fraction

BACKGROUND

Although pulse-wave velocity (PWV) is a recognized risk predictor for cardiovascular diseases, its association with cardiovascular outcomes in heart failure with preserved left ventricular ejection fraction (HFpEF) is unclear.

METHODS AND RESULTS

The 502 patients with HFpEF finally enrolled in this study (mean follow-up duration: 1017 days) were divided into those with or without peripheral artery disease (PAD). The latter were further grouped according to brachial-ankle PWV (baPWV) quintiles using an ankle-brachial pressure index device. Kaplan-Meier analysis revealed a significantly higher risk of all-cause mortality and total cardiovascular events (both P = 0.01) in HFpEF patients with than without PAD. Multivariate Cox hazard analysis, including predictors identified as significant by simple Cox hazard analysis, identified PAD as a significant and independent predictor of cardiovascular events (hazard ratio: 1.85; 95% confidence interval: 1.01-3.39; P = 0.04). In an analysis of HFpEF patients without PAD grouped according to baPWV quintiles, estimated glomerular filtration rate (r = 0.21, P < 0.01) and hemoglobin (r = 0.18, P = 0.01) levels correlated negatively with baPWV. In the Kaplan-Meier analysis, patients with a baPWV more than 1900 cm/s and those with the lowest baPWV (<1300 cm/s) had a significantly higher frequency of total cardiovascular events than patients with 1300 baPWV or less which is less than 1900, indicating a J-shaped association between baPWV and total cardiovascular events as well as similarities to HFpEF patients with PAD. By contrast, the lowest baPWV group had the highest risk of heart failure-related events, accompanied by the highest brain natriuretic peptide levels.

CONCLUSION

Identifying complications of PAD and measuring baPWV values in HFpEF patients can improve risk stratification.

Effect of Obesity on Blood Pressure and Arterial Stiffness in Middle-Aged Korean Women

Objectives

Our study aims to provide basic scientific data on the importance of obesity management in middle-aged Korean women by analyzing its effects on blood pressure and arterial stiffness. In addition, we examined the correlations of these two parameters.

Methods

The study participants were 40 middle-aged female volunteers, who were classified into obesity group (n = 20) and normal weight group (n = 20). Statistical analysis was performed using independent t-test and the Pearson correlation coefficient was used to correlate blood pressure and arterial stiffness.

Results

This study evaluated the systolic blood pressure, diastolic blood pressure, and pulse wave velocity (PWV). These results were higher in the obesity group than the normal weight group. Furthermore, blood pressure and arterial stiffness (PWV, augmentation pressure) were static correlated.

Conclusion

Obesity is closely related to blood pressure and arterial stiffness. Therefore, indices for blood pressure and arterial stiffness may play a vital role in predicting and preventing obesity and its sequelae.

Segmental arterial stiffness in relation to B-type natriuretic peptide with preserved systolic heart function

Background

Central arterial stiffness has been shown to play a key role in cardiovascular disease. However, evidence regarding such arterial stiffness from various arterial segments in relation to B-type natriuretic peptide (BNP) remains elusive.

Methods

A total of 1255 participants (47.8% men; mean age: 62.6 ± 12.3 [SD] years) with preserved left ventricular function (ejection fraction ≥50%) and ≥1 risk factors were consecutively studied. Arterial pulse wave velocity (PWV) by automatic device (VP-2000; Omron Healthcare) for heart-femoral (hf-PWV), brachial-ankle (ba-PWV), and heart-carotid (hc-PWV) segments were obtained and related to BNP concentrations (Abbott Diagnostics, Abbott Park, IL, USA).

Results

Subjects in the highest hf-PWV quartile were older and had worse renal function and higher blood pressure (all P < 0.05). Elevated PWV (m/s) was correlated with elevated BNP (pg/ml) (beta coefficient = 19.3, 12.4, 5.9 for hf-PWV, ba-PWV, hc-PWV respectively, all p < 0.05). After accounting for clinical co-variates and left ventricle mass index (LVMI), both hf-PWV and ba-PWV were correlated with higher BNP (beta coefficient = 8.3, 6.4 respectively, P < 0.01 for each). Adding both hf-PWV and ba-PWV to LVMI significantly expanded ROC in predicting abnormal BNP>100 pg/ml (both P < 0.01), but only hf-PWV presented significant integrated discrimination improvement to predict risk for BNP concentrations (0.7%, P = 0.029).

Conclusion

A significant segmental PWV associated with biomarker BNP concentrations suggests that arterial stiffness is associated with myocardial damage.

Wave intensity of aortic root pressure as diagnostic marker of left ventricular systolic dysfunction

Background

Systolic left ventricular function strongly influences the blood pressure waveform. Therefore, pressure-derived parameters might potentially be used as non-invasive, diagnostic markers of left ventricular impairment. The aim of this study was to investigate the performance of pressure-based parameters in combination with electrocardiography (ECG) for the detection of left ventricular systolic dysfunction defined as severely reduced ejection fraction (EF).

Methods and results

Two populations, each comprising patients with reduced EF and pressure-matched controls, were included for the main analysis (51/102 patients) and model testing (44/88 patients). Central pressure was derived from radial readings and used to compute blood flow. Subsequently, pulse wave analysis and wave intensity analysis were performed and the ratio of the two peaks of forward intensity (SDR) was calculated as a novel index of ventricular function. SDR was significantly decreased in the reduced EF group (2.5 vs. 4.4, P<0.001), as was central pulse pressure, augmentation index and ejection duration (ED), while the QRS-duration was prolonged. SDR and ED were independent predictors of ventricular impairment and when combined with QRS in a simple decision tree, a reduced EF could be detected with a sensitivity of 92% and a specificity of 80%. The independent power of ED, SDR and QRS to predict reduced EF was furthermore confirmed in the test population.

Conclusion

The detection or indication of reduced ejection fraction from pressure-derived parameters seems feasible. These parameters could help to improve the quality of cardiovascular risk stratification or might be used in screening strategies in the general population.

Does aortic pulse wave velocity have any prognostic significance in advanced heart failure patients?

Introduction: Noninvasive measurement of arterial stiffness by pulse-wave velocity (PWV) has prognostic value in different sub groups of cardiovascular disorders. We aimed to measure the PWV in advanced heart failure (HF) patients with reduced left ventricular ejection fraction (LVEF) and investigate whether it has any prognostic significance in this group of patients. Methods: Between 2013 to 2015 patients with a diagnosis of advanced HF (LVEF ≤ 30%) scheduled for right heart catheterization (RHC) were included in our study. PWV was measured before RHC in each patient using vascular explorer device (Enverdis GmbH) in catheterization laboratory. The patients were subsequently followed for 6 months and their hospitalization or death (composite of all-cause death/hospitalization) were recorded. Results: A total of 50 patients (38 men) were enrolled. The mean (SD) of age was 45 (16) years. The mean PWV was 6.8 m/s. There was no statistically significant correlation between the PWV and the clinical, echocardiographic and RHC data. The PWV was not different in patients with or without composite of all-cause death/hospitalization (7.3 versus 6.3, P > 0.05). In this study cardiac output (CO) (beta = -0.53, P = 0.02, odds ratio = 0.6, 95% CI = 0.4-0.9), pulse pressure (PP) (beta = -0056, P = 0.03, odds ratio=0.95, 95% CI = 0.89-0.99) and age (beta = -0.045, P = 0.05, odds ratio = 0.96, 95% CI = 0.9-1.001) were independent predictors of composite of all-cause death/ hospitalization. Conclusion: In patients with advanced systolic HF, PWV may not be a good prognostic factor and does not have any added value over previous well known prognostic factors.

The usefulness of brachial-ankle pulse wave velocity in predicting long-term cardiovascular events in younger patients

Brachial-ankle pulse wave velocity (baPWV) is known as a significant predictor of cardiovascular events. However, the previous studies have not considered age, which can affect the baPWV value. We evaluated the predictive value of baPWV for cardiovascular events in various age groups. From January 2005 to December 2012, all patients admitted to our department with any cardiovascular disease and underwent ankle-brachial index (ABI) measurement were enrolled in the IMPACT-ABI registry. The primary endpoints included major adverse cardiovascular events (MACE; cardiovascular death, myocardial infarction, and stroke). Of the 3131 patients enrolled, 2554 were included in the analysis, whereas 577 were excluded due to missing baPWV data, ABI ≤0.9 and/or >1.4, and the previous endovascular therapy and/or surgical treatment for peripheral artery disease. Patients were divided according to age 30-59 years (n = 580), 60-69 years (n = 730), 70-79 years (n = 862), and ≥80 years (n = 330). The cumulative incidence of MACE through 5 year was significantly higher in the high baPWV group (>1644 cm/s) than in the low baPWV group (≤1644 cm/s; 8.7 vs. 4.6%; log-rank: p < 0.001). However, among the age groups, only the 30-59-year group showed a significant difference in MACE incidence between those with high and low baPWV (7.0 vs. 0.9%; log-rank: p = 0.001). In conclusion, the baPWV could serve as a useful marker to predict cardiovascular events, particularly among younger patients.

Determinants and covariates of central pressures and wave reflections in systolic heart failure

BACKGROUND

In general, higher blood pressure levels and increased central pulsatility are indicators for increased cardiovascular risk. However, in systolic heart failure (SHF), this relationship is reversed. Therefore, the aim of this work is to compare pulsatile hemodynamics between patients with SHF and controls and to clarify the relationships between measures of cardiac and arterial function in the two groups.

METHODS

We used parameters derived from angiography, echocardiography, as well as from pulse wave analysis (PWA) and wave separation analysis (WSA) based on non-invasively assessed pressure and flow waves to quantify cardiac function, aortic stiffness and arterial wave reflection in 61 patients with highly reduced (rEF) and 122 matched control-patients with normal ejection fraction (nEF).

RESULTS

Invasively measured pulse wave velocity was comparable between the groups (8.6/8.05 m/s rEF/nEF, P = 0.24), whereas all measures derived by PWA and WSA were significantly decreased (augmentation index: 18.1/24.8 rEF/nEF, P < 0.01; reflection magnitude: 56.3/62.1 rEF/nEF, P < 0.01). However, these differences could be explained by the shortened ejection duration (ED) in rEF (ED: 269/308 ms rEF/nEF, P < 0.01; AIx: 22.2/22.8 rEF/nEF, P = 0.7; RM: 59.3/60.6 rEF/nEF, P = 0.47 after adjustment for ED). Ventricular function was positively associated with central pulse pressures in SHF in contrast to no or even a slightly negative association in controls.

CONCLUSIONS

The results suggest that the decreased measures of pulsatile function may be caused by impaired systolic function and altered interplay of left ventricle and vascular system rather than by a real reduction of wave reflections or aortic stiffness in SHF.

Associations between plasma fibulin-1, pulse wave velocity and diabetes in patients with coronary heart disease

BACKGROUND

Diabetes is related to increased risk of cardiovascular disease, and arterial stiffness and its consequences may be the factor connecting the two. Arterial stiffness is often measured by carotid-femoral pulse wave velocity (cf-PWV), but no plasma biomarker reflecting arterial stiffness is available. Fibulin-1 is an extracellular matrix protein, up-regulated in arterial tissue and in plasma in patients with type 2 diabetes. We aimed to evaluate the association between plasma fibulin-1 and arterial stiffness measured by cf PWV in a group of patients with diabetes, and one without, all undergoing coronary artery bypass grafting.

METHODS

Pulse wave velocity (PWV) and pulse wave analysis including augmentation index (Aix75) was measured in 273 patients, who subsequently underwent a coronary by-pass operation. Plasma samples were drawn and information was gathered on diabetes status, HbA1c, lipids, medication, body mass index, co-morbidities and smoking status. Carotid artery intima-media thickness, as well as estimation of carotid artery plaque burden, and distal blood pressure was also obtained.

RESULTS

Sixty three patients had diabetes, and this group had significantly higher levels of plasma fibulin-1, PWV and Aix75, compared to the 210 patients who did not have diabetes. In univariate analysis fibulin-1 and pulse wave velocity were not correlated in either group whereas fibulin-1 in patients without diabetes was correlated to Aix75.

CONCLUSION

Fibulin-1 and arterial stiffness indices are not directly related in patients with cardiac disease, despite the fact that both measures are increased among patients with diabetes.

Non-invasive wave reflection quantification in patients with reduced ejection fraction

The non-invasive quantification of arterial wave reflection is an increasingly important concept in cardiovascular research. It is commonly based on pulse wave analysis (PWA) of aortic pressure. Alternatively, wave separation analysis (WSA) considering both aortic pressure and flow waveforms can be applied. Necessary estimates of aortic flow can be measured by Doppler ultrasound or provided by mathematical models. However, this approach has not been investigated intensively up to now in subjects developing systolic heart failure characterized by highly reduced ejection fraction (EF). We used non-invasively generated aortic pressure waveforms and Doppler flow measurements to derive wave reflection parameters in 61 patients with highly reduced and 122 patients with normal EF. Additionally we compared these readings with estimates from three different flow models known from literature (triangular, averaged, Windkessel). After correction for confounding factors, all parameters of wave reflection (PWA and WSA) were comparable for patients with reduced and normal EF. Wave separations assessed with the Windkessel based model were similar to those derived from Doppler flow in both groups. The averaged waveform performed poorer in reduced than in normal EF, whereas triangular flow represented a better approximation for reduced EF. Overall, the non-invasive assessment of WSA parameters based on mathematical models compared to ultrasound seems feasible in patients with reduced EF.

The Ankle-Brachial Index Is Related to Left Ventricular Ejection Fraction in Bonnet Macaques

Low ankle-brachial index (ABI) is a marker of peripheral arterial disease associated with higher cardiovascular risk. ABI has been found to be influenced by left ventricular ejection fraction (LVEF), but this relation is confounded by atherosclerosis. <b><i>Objectives:</i></b> Since nonhuman primates have a low incidence of atherosclerosis, we sought to evaluate the effect of LVEF on ABI in 24 healthy female bonnet macaques (age 83 ± 21 months). <b><i>Methods:</i></b> LVEF was determined by echocardiography during anesthesia with ketamine. ABI was determined using automatic blood pressure cuff. <b><i>Results:</i></b> Mean LVEF was 73 ± 6%. Mean ABI was 1.03 (range 0.78-1.17) with similar right and left lower limb values (p = 0.78). On univariate analysis, mean ABI was significantly correlated with LVEF (r = 0.58, p = 0.003) but not with age, crown-rump length or weight. Mean LVEF increased in a stepwise manner from lowest to highest ABI tertile (68 ± 6 vs. 73 ± 4 vs. 77 ± 5%, p = 0.008). On ordinal regression and forced multivariate linear analyses, ABI status was independently related to LVEF. <b><i>Conclusions:</i></b> ABI is influenced by left ventricular systolic function but not age, height, weight or mass index in bonnet macaques. Left ventricular systolic function should be accounted for when considering ABI measurements.

Components of hemodynamic load and cardiovascular events: the Framingham Heart Study

BACKGROUND

Elevated blood pressure is the leading modifiable risk factor for cardiovascular disease (CVD) and premature death. The blood pressure waveform consists of discrete hemodynamic components, derived from measured central pressure and flow, which may contribute separately to risk for an adverse outcome. However, pressure-flow measures have not been studied in a large, community-based sample.

METHODS AND RESULTS

We used proportional hazards models to examine the association of incident CVD with forward pressure wave amplitude, mean arterial pressure, and global reflection coefficient derived from wave separation analysis and echocardiography in 2492 participants (mean age 66±9 years, 56% women) in the Framingham Heart Study. During follow-up (0.04-6.8 years), 149 participants (6%) had a CVD event. In multivariable models adjusting for age, sex, antihypertensive therapy, body mass index, heart rate, total and high-density lipoprotein cholesterol concentrations, smoking, and the presence of diabetes mellitus, forward pressure wave amplitude (hazard ratio, 1.40; 95% confidence interval, 1.16-1.67; P=0.0003) was associated with incident CVD, whereas mean arterial pressure (hazard ratio, 1.10; 95% confidence interval, 0.94-1.29; P=0.25) and global wave reflection (hazard ratio, 0.93; 95% confidence interval, 0.78-1.12; P=0.58) were not. After adding systolic blood pressure and carotid-femoral pulse wave velocity to the model, forward pressure wave amplitude persisted as a correlate of events (hazard ratio, 1.33; 95% confidence interval, 1.05-1.68; P=0.02).

CONCLUSIONS

Higher forward pressure wave amplitude (a measure of proximal aortic geometry and stiffness) was associated with increased risk for incident CVD, whereas mean arterial pressure and relative wave reflection (correlates of resistance vessel structure and function) were not associated with increased risk for incident CVD.

Pulse wave analysis of the aortic pressure waveform in patients with vasovagal syncope

Vascular reflex mechanisms contribute to vasovagal syncope. However, the alterations in central haemodynamics in patients with vasovagal syncope are unknown. 30 consecutive patients (36.5 ± 15 years, 14 females) with recurrent vasovagal syncope (VVS) and a positive tilt table test were compared to 39 age- and sex-matched controls (36.9 ± 16 years, 15 females) with a negative tilt table result and no history of syncope. Central aortic pressure parameters including augmentation index and central pulse pressure as markers of aortic stiffness were generated non-invasively by applanation tonometry of the radial artery and use of a validated mathematical transfer function. No difference in aortic augmentation index was observed between groups. (VVS 9 ± 2.6 vs. Control 11 ± 2.4, p = 0.8). However, in patients with vasovagal syncope the aortic pressure waveform significantly differed from healthy controls. A prolonged time to the peak of aortic pressure wave (aortic T2) was observed in patients with vasovagal syncope (226 ± 24 vs. 208 ± 21 ms, p = 0.001). Furthermore time to the first shoulder of the aortic pressure wave (aortic T1) was slightly shorter compared to healthy controls, but did not reach statistical significance (106 ± 22 vs. 110 ± 12 ms, p = 0.33). Patients with vasovagal syncope have an altered aortic pressure waveform at rest, but no signs of elevated aortic stiffness. The underlying mechanisms for these findings may potentially result from a complex imbalance of the autonomic nervous system with a continuous deregulation of the sympathetic and parasympathetic reflex arcs.

The effect of lower body weight support on arterial wave reflection in healthy adults

Body weight support (WS) during treadmill exercise is used to rehabilitate orthopedic/neurological patients. WS lowers musculoskeletal strain and load. It compresses the lower body and increases intrathoracic volume. We studied short-term effects of WS on wave reflection indices using applanation tonometry during progressive WS of 25%, 50%, and 75% of body weight in 25 healthy men. WS decreased mean heart rate from 79 to 69 beats/min (P < .001). Peripheral and central mean arterial, systolic, and pulse pressures (PP) remained unchanged. There was a trend toward lower peripheral and central diastolic pressure. PP amplification ratio decreased significantly (P = .005). Reflected wave characteristics: Augmented pressure and index increased in a stepwise manner with WS (both P < .001). Both ejection duration and systolic duration of the reflected pressure wave (Ätr) increased progressively (both P < .001). The round-trip travel time (Δtp) was unchanged. Left ventricular workload and oxygen demand: Left ventricular wasted pressure energy increased (P < .001), and the subendocardial viability ratio decreased (P = .005), whereas the tension time index remained unchanged. In normal men, WS acutely decreases the PP amplification ratio, increases the amplitude and duration of the reflected aortic pressure wave, and increases measures of wasted left ventricular pressure energy and oxygen demand.

A randomized pilot study of aortic waveform guided therapy in chronic heart failure

BACKGROUND

Medication treatment decisions in heart failure (HF) are currently informed by measurements of brachial artery pressure, but ventricular afterload is more accurately represented by central aortic pressure, which differs from brachial pressure. We sought to determine whether aggressive titration of vasoactive medicines beyond goal-directed heart failure medical therapy (GDMT) based upon aortic pressure improves exercise capacity and cardiovascular structure-function.

METHODS AND RESULTS

Subjects with chronic HF (n=50) underwent cardiopulmonary exercise testing, echocardiography, and arterial tonometry to measure aortic pressure and augmentation index, and were then randomized to aortic pressure-guided treatment (active, n=23) or conventional therapy (control, n=27). Subjects returned for 6 monthly visits wherein GDMT was first optimized. Additional vasoactive therapies were then sequentially added with the goal to reduce aortic augmentation index to 0% (active) or if brachial pressure remained elevated (control). Subjects randomized to active treatment experienced greater improvement in peak oxygen consumption compared with controls (1.37±3.76 versus -0.65±2.21 mL min(-1) kg(-1), P=0.025) though reductions in aortic augmentation index were similar (-7±9% versus -5±6%, P=0.46). Forward stroke volume increased while arterial elastance and left ventricular volumes decreased in all participants, with no between-group difference. Subjects randomized to active treatment were more likely to receive additional vasoactive therapies including nitrates, aldosterone antagonists and hydralazine, with no increased risk of hypotension or worsening renal function.

CONCLUSIONS

Maximization of goal-directed medical therapy in heart failure patients may enhance afterload reduction and lead to reverse remodeling, while additional medicine titration based upon aortic pressure data improves exercise capacity in patients with heart failure.

Opposite Predictive Value of Pulse Pressure and Aortic Pulse Wave Velocity on Heart Failure With Reduced Left Ventricular Ejection Fraction

Although hypertension contributes significantly to worsen cardiovascular risk, blood pressure increment in subjects with heart failure is paradoxically associated with lower risk. The objective was to determine whether pulse pressure and pulse wave velocity (PWV) remain prognostic markers, independent of treatment in heart failure with reduced left ventricular function. The investigation involved 6632 patients of the Eplerenone Post–Acute Myocardial Infarction Heart Failure Efficacy and Survival Study. All subjects had acute myocardial infarction with left ventricular ejection fraction <40% and signs/symptoms of heart failure. Carotid-femoral PWV was measured in a subpopulation of 306 subjects. In the overall population, baseline mean arterial pressure <90 mm Hg was associated with higher all-cause death (hazard ratio, 1.14 [95% confidence interval, 1.00–1.30]; P <0.05), whereas higher left ventricular ejection fraction or pulse pressure was associated with lower rates of all-cause death, cardiovascular death/hospitalization, and cardiovascular death. In the subpopulation, increased baseline PWV was associated with worse outcomes (all-cause death: 1.16 [1.03–1.30]; P <0.05 and cardiovascular deaths: 1.16 [1.03–1.31]; P <0.05), independent of age and left ventricular ejection fraction. Using multiple regression analysis, systolic blood pressure and age were the main independent factors positively associated with pulse pressure or PWV, both in the entire population or in the PWV substudy. In heart failure and low ejection fraction, our results suggest that pulse pressure, being negatively associated with outcome, is more dependent on left ventricular function and thereby no longer a marker of aortic elasticity. In contrast, increased aortic stiffness, assessed by PWV, contributes significantly to cardiovascular death.

Site-specific coupling between vascular wall thickness and function: an observational MRI study of vessel wall thickening and stiffening in hypertension

OBJECTIVES

The objective of this study was to evaluate associations between aortic pulse wave velocity (PWV) and aortic and carotid vessel wall thickness (VWT) using cardiovascular magnetic resonance imaging (MRI) in patients with hypertension as compared with healthy adult volunteers.

MATERIALS AND METHODS

Local medical ethics approval was obtained and the participants gave informed consent. Fifteen patients with hypertension (5 men and 10 women; mean [SD] age, 49 [14] years) and 15 age- and sex-matched healthy volunteers were prospectively included and compared. All participants underwent MRI examination for measuring aortic and carotid VWT and aortic PWV with well-validated MRI techniques at 1.5- and 3-T MRI systems: PWV was assessed from velocity-encoded MRI and VWT was assessed by using dual-inversion black-blood gradient-echo imaging techniques. Paired t tests were used for testing differences between the volunteers and the patients and Pearson correlation (r) and univariable and multivariable stepwise linear regression analyses were used to test associations between aortic and carotid arterial wall thickness and stiffness.

RESULTS

Mean values for aortic PWV and aortic and carotid VWT (indexed for body surface area [BSA]) were all significantly higher in patients with hypertension as compared with the healthy volunteers (ie, aortic PWV, 7.0 ± 1.4 m/s vs 5.7 ± 1.3 m/s; aortic VWT/BSA, 0.12 ± 0.03 mL/m vs 0.10 ± 0.03 mL/m; carotid VWT/BSA, 0.04 ± 0.01 mL/m vs 0.03 ± 0.01 mL/m; all P < 0.01). Aortic PWV was highly correlated with aortic VWT/BSA (r = 0.76 and P = 0.002 in the patients vs r = 0.63 and P = 0.02 in the volunteers), and in the patients, aortic PWV was moderately correlated with carotid VWT/BSA (r = 0.50; P = 0.04). In the volunteers, correlation between aortic PWV and carotid VWT/BSA was not significant (r = 0.40; P = 0.13). In addition, aortic VWT/BSA was significantly correlated with carotid VWT/BSA, in both the patients (r = 0.60; P = 0.005) and volunteers (r = 0.57; P = 0.007).

CONCLUSIONS

In the patients with hypertension and the healthy volunteers, the aortic PWV is associated more strongly with aortic wall thickness than with carotid wall thickness, reflecting site-specific coupling between vascular wall thickness and function.

Elastic properties of peripheral arteries in heart failure patients in comparison with normal subjects

Understanding the change in elastic properties of peripheral arteries in heart failure patients is of particular importance, especially when compared with normal subjects. To investigate factors associated with their difference, 40 normal subjects and 60 heart failure patients were studied. Electrocardiograms, carotid pulses and radial pulses were simultaneously recorded to determine carotid-radial pulse transit time (carotid-radial PTT), arm pulse wave velocity (PWV), and arterial volume distensibility. In comparison with normal subjects, carotid-radial PTT was lower by 8 ms in heart failure patients, arm PWV higher by 1.4 m/s, and peripheral arterial distensibility lower by 0.04 % per mmHg (all significant, P < 0.01). Peripheral arterial distensibility was significantly related to systolic blood pressure (SBP) and to left ventricular ejection fraction (LVEF) for heart failure patients (both P < 0.001), but the relationship for the normal group was not statistically significant (both 0.05 < P<0.1). Ageing had a significant inverse relationship with arterial distensibility in normal subjects (P < 0.05), but not in heart failure patients (P = 0.59). No subject in the normal group had an arterial distensibility lower than 0.1 % per mmHg, in comparison with 28 % (17/60) in the heart failure group. Peripheral arterial distensibility has been shown to be significantly lower in heart failure patients in comparison with normal subjects. High SBP and low LVEF were the main factors associated with low arterial distensibility in heart failure patients.

Aortic augmentation index and pulse wave velocity in response to head-up tilting: effect of autonomic failure

BACKGROUND

Aortic augmentation index (AIx) but not carotid-femoral pulse wave velocity (cfPWV) has reported to decrease in response to vasodilators, which has been related to changes in the timing and/or intensity of wave reflection. Yet, recent evidence indicates that arterial reservoir pressure rather than wave reflection is the most important determinant of AIx.

METHODS

Using radial artery applanation tonometry and a general transfer function AIx, aortic pulse wave reflection time and cfPWV (foot-to-foot method) were determined in 10 patients with severe autonomic failure and in 14 healthy individuals during supine rest and graded head-up tilting.

RESULTS

During supine rest, mean blood pressure (BP) (127.6 ± 21.5 and 97.5 ± 9.4 mmHg), AIx (32.4 ± 13.0 and 23.1 ± 8.7%) and cfPWV (12.1 ± 3.6 and 8.9 ± 1.6 m/s) were higher in patients than in controls. In patients, BP decreased by 18.7 ± 9.8 and 39.6 ± 11.7%, AIx by 39.2 ± 27.5 and 100.9 ± 78.1% and cfPWV by 12.0 ± 10.5 and 27.7 ± 13.5% in response to 30 and 60° head-up tilting. Decreases in AIx and cfPWV correlated with the BP fall (r = 0.67, P = 0.001 and r = 0.75, P < 0.001), but changes in AIx and cfPWV were unrelated. In controls, AIx during head-up tilting decreased despite increases in vascular tone and cfPWV. Aortic reflection time in patients and controls during tilting did not change. Stepwise regression analysis revealed that 68% of the variation in AIx could be explained by the BP fall and reflection time and 76% of the variation in cfPWV by the BP fall and sex.

CONCLUSION

In a clinical model of autonomic failure, both AIx and cfPWV largely depend on instantaneous BP, but these two variables are unrelated, supporting the contention that aortic reservoir pressure rather than wave reflection is the main determinant of AIx.

Circulating vascular growth factors and central hemodynamic load in the community

Mean and pulsatile components of hemodynamic load are related to cardiovascular disease. Vascular growth factors play a fundamental role in vascular remodeling. The links between growth factors and hemodynamic load components are not well described. In 3496 participants from the Framingham Heart Study third generation cohort (mean age: 40±9 years; 52% women), we related 4 tonometry-derived measures of central arterial load (carotid femoral pulse wave velocity and forward pressure wave, mean arterial pressure, and the global reflection coefficient) to circulating concentrations of angiopoietin 2, its soluble receptor; vascular endothelial growth factor, its soluble receptor; hepatocyte growth factor; insulin-like growth factor 1; and its binding protein 3. Using multivariable linear regression models, adjusted for standard cardiovascular risk factors, serum insulin-like growth factor 1 concentrations were negatively associated with carotid femoral pulse wave velocity, mean arterial pressure, and reflection coefficient (P≤0.01 for all), whereas serum vascular endothelial growth factor levels were positively associated with carotid femoral pulse wave velocity and mean arterial pressure (P<0.04). Serum insulin-like growth factor binding protein 3 and soluble angiopoietin 2 receptor levels were positively related to mean arterial pressure and to forward pressure wave, respectively (P<0.05). In our cross-sectional study of a large community-based sample, circulating vascular growth factor levels were related to measures of mean and pulsatile hemodynamic load in a pattern consistent with the known physiological effects of insulin-like growth factor 1 and vascular endothelial growth factor.

Significant relationship between changes in brachial-ankle pulse wave velocity relative to blood pressure elevation and coronary artery disease

OBJECTIVES

Based on well-established physiological theories, we studied correlations between changes in brachial-ankle pulse wave velocity (baPWV) relative to blood pressure (BP) elevation (elasticity of large-to-medium-sized arteries), and coronary artery disease (CAD).

METHODS

The baPWV (in centimeters/second) and BP (in millimeters of mercury) were determined in 101 patients before, during, and/or after a cold pressor test using a volume-plethysmographic system.

RESULTS

Significantly higher rates of increase in PWV relative to changes in BP were observed in the CAD(+) group than in the CAD(-) group when mean BP [median (25th-75th percentiles): 14.8 (8.3-24.9) vs. 8.6 (5.7-11.4) cm/s/mmHg, P<0.0001], and systolic [10.1 (6.0-17.5) vs. 6.4 (4.4-10.6) cm/s/mmHg, P=0.0023] and diastolic BP [21.0 (14.0-34.4) vs. 10.8 (6.8-16.1) cm/s/mmHg, P<0.0001] were used as BP indices. Similarly, the rates of increase in baPWV showed a significant correlation with the extent of CAD. The rate of increase in baPWV obtained using the mean, systolic and diastolic BP as indices showed an area under the receiver operating characteristic curve of 0.68-0.76, sensitivity of 65-75%, and specificity of 65-75% for the detection of CAD. The area under the receiver operating characteristic curve, sensitivity, and specificity for the rate of increase were slightly higher than those for baseline baPWV and baseline baPWV/baseline BP ratio, but not to a significant degree.

CONCLUSION

The rate of increase in baPWV relative to BP elevation determined by cold pressor test is significantly and moderately correlated with CAD. To identify patients with CAD, the rate of increase in baPWV relative to changes in BP can provide considerable, but limited, information.

Relation of the ankle brachial index to left ventricular ejection fraction

Low and high ankle brachial index (ABI) values are both a marker of peripheral arterial disease and associated with greater cardiovascular disease event rates. The objective of the present study was to determine whether the ABI is associated with left ventricular (LV) systolic function. We studied 175 patients (age 67 +/- 13 years, 58% men) referred for ABI determination who had had the LV ejection fraction (EF) determined using echocardiography within 14 days. The mean LVEF was 47 +/- 13%, mean ABI for the right leg was 0.93 +/- 0.32, and the mean ABI for the left leg was 0.94 +/- 0.26. Of the 175 patients, 91 (52%) had a low, 69 (39%) had a normal, and 15 (9%) had a high ABI. The mean LVEF increased in a stepwise manner from the low, to normal, to abnormally high ABI groups (43 +/- 13% vs 51 +/- 12% vs 57 +/- 5%, respectively; p <0.01). On ordinal regression analysis, ABI status was independently related to LVEF. For each 1% increase in LVEF, the odds of being in the higher category of ABI increased by 1.08 (95% confidence interval 1.02 to 1.12, p = 0.002). No significant interaction was seen between coronary artery disease and LVEF on the ABI (p = 0.48). In conclusion, the ABI might be influenced by LV systolic function, independent of coronary disease. LVEF should be considered when ABI values are used to evaluate and monitor cardiovascular risk in patients.

Pulse wave analysis of the aortic pressure waveform in severe left ventricular systolic dysfunction

BACKGROUND

The effect of moderate left ventricular systolic dysfunction (LVSD) on ventricular/vascular coupling and the aortic pressure waveform (AoPW) has been well described, but the effect of severe LVSD has not.

METHODS AND RESULTS

We used noninvasive, high-fidelity tonometry of the radial artery and a mathematical transfer function to generate the AoPW in 25 treated patients with LVSD (mean LV ejection fraction, 24+/-8.8%; range, 11% to 40%; 21 patients <30%). Pulse wave analysis of the AoPW was used to characterize ventricular/vascular coupling and compared with pulse wave analysis performed in 25 normal subjects matched for age, gender, height, body mass index, and heart rate. Measurements obtained using pulse wave analysis in LVSD patients indicated features of poor LV stroke performance and also reduced indices of arterial stiffness: increased travel time of the pressure wave (147+/-10 ms versus 132+/-21 ms; P<0.001); decreased systolic duration of reflected wave (134+/-24 ms versus 167+/-26 ms; P<0.001); ejection duration (277+/-22 ms versus 299+/-25 ms; P<0.008); percent systolic duration (32+/-5.3% versus 35+/-4.0%; P<0.02); aortic systolic pressure (100+/-16 mm Hg versus 121+/-16 mm Hg; P<0.001); unaugmented pressure (24+/-6.3 mm Hg versus 32+/-6.4 mm Hg; P<0.001); augmented pressure (4.8+/-3.1 mm Hg versus 9.6+/-4.5 mm Hg; P<0.001); pulse pressure (28+/-7.4 mm Hg versus 42+/-9.5 mm Hg; P<0.001); augmentation index (12+/-6.6% versus 23+/-7.6%; P<0.006); wasted LV effort (5.3+/-2.8x10(2) dyne sec/cm(2) versus 17+/-10x10(2) dyne sec/cm(2); P<0.001); systolic pressure time index (17+/-4.1x10(2) mm Hg-sec/min versus 23+/-4.2x10(2) mm Hg sec/min; P<0.001); and pressure systolic area (383+/-121 mm Hg sec/min versus 666+/-150 mm Hg sec/min; P<0.001).

CONCLUSIONS

Severe LVSD causes measurable changes in the AoPW. Standardization of AoPW findings in LVSD patients may allow for the clinical use of radial artery pulse wave analysis to noninvasively determine the severity of dysfunction and aid in logical therapy.

The arterial pulse wave and vascular compliance

For just over 1 century, we have relied on cuff sphygmomanometry to measure blood pressure at a peripheral (brachial) site. This measurement provides a quantitative snapshot of hemodynamic activity at 1 part of the arterial tree. Because the heart and brain are exposed to central (aortic) and not peripheral (brachial) pressure, it might be timely for nurses to start looking at alternative techniques to provide more meaningful information on central hemodynamics. The noninvasive technique of applanation tonometry allows such measurements to be performed quickly in the nursing clinic. By analyzing the pulse wave and calculating pulse wave velocity, the technique also assesses arterial "stiffness." This method of cardiovascular assessment further enables nurses to monitor the central effects of antihypertensive, lipid lowering, and other drug therapy over time.

Radial augmentation index unmasks premature coronary artery disease in younger males

OBJECTIVE

The augmentation index, a marker of arterial wave reflection, is considered to indicate cardiovascular risk burden, particularly in younger persons. We assessed whether the easily obtainable radial augmentation index (rAIx) is superior to systolic blood pressure (SBP) or pulse pressure (PP) in detecting atherosclerotic vascular disease at an early age.

METHODS

We determined rAIx by applanation tonometry, SBP and PP in 152 male patients with or without invasively documented coronary artery disease (CAD). Ejection fraction (EF) was visually estimated by echocardiography or left ventricular angiography.

RESULTS

In younger patients (age < or =60 years, EF > or =30%), rAIx was significantly higher in patients with CAD (79.8+/-13.5%, n=31) compared with patients without CAD (68.5+/-22.0%, n=21; P = 0.04), whereas SBP (121+/-16 vs. 131+/-18 mmHg, P=0.04) and PP (48.7+/-9.4 vs. 56.3+/-12.1 mmHg, P=0.01) were even lower in patients with CAD compared with patients without CAD. In patients aged < or =60 years, rAIx was highest when EF was less than 30% (90.0+/-9.2%) compared with patients with EF 30-54% (80.7+/-11.5%) or EF > or =55% (72.1+/-20.4%, P=0.01). In contrast, in patients above 60 years of age, rAIx, SBP or PP did not differ between patients with or without CAD and the rAIx tended to be lowest in patients with severely reduced EF (P=0.07).

CONCLUSION

We conclude that premature vascular disease in younger patients with CAD is reflected only by an elevated rAIx, and not by SBP or PP. The rAIx is not suited to distinguish between older patients with high or low cardiovascular risk. Age seems to influence the interplay between rAIx and systolic heart function.

Relation of adiponectin and high-sensitivity C-reactive protein to pulse-wave velocity and N-terminal pro-B-type natriuretic peptide in the general population

The roles of metabolic syndrome and chronic subclinical inflammation in arterial stiffening and the development of heart failure remain to be elucidated. Whether adiponectin and high-sensitivity C-reactive protein (hs-CRP) were independently related to brachial-ankle pulse-wave velocity (ba-PWV) and N-terminal pro-brain natriuretic peptide (NT-pro-BNP) in the general population were investigated. Eligible study subjects were 445 Chinese residents aged > or =40 years who participated in a community-based survey, underwent examination of ba-PWV, and had complete data of serum adiponectin, hs-CRP (<10 mg/L), and NT-pro-BNP. Adiponectin, but not hs-CRP, was independently related to ba-PWV (standardized regression parameter -0.107, p <0.05) when age, gender, body mass index, and number of metabolic syndrome components were accounted for. On the other hand, ba-PWV, adiponectin, and hs-CRP were independently related to NT-pro-BNP (standardized regression parameters 0.116, 0.188, and 0.094, respectively; all p <0.05) when age, gender, body mass index, number of metabolic syndrome components, and renal function were accounted for. In conclusion, adiponectin, but not hs-CRP, is independently associated with both ba-PWV and NT-pro-BNP in the general population. Because adiponectin, hs-CRP, ba-PWV, and NT-pro-BNP may represent markers for metabolic syndrome, chronic subclinical inflammation, arterial stiffness, and ventricular dysfunction, respectively, our results suggest that adiponectin may directly modulate both arterial stiffening and ventricular dysfunction. In contrast, hs-CRP may independently contribute to ventricular dysfunction, but not arterial stiffening.

Role of the augmentation index in hypertension

Recent studies have revealed the clinical usefulness of central blood pressure (BP) as an index of risk for cardiovascular disease. The arterial pulse waveform is the sum of the forward pressure wave generated by left ventricular ejection and a backward propagating wave that is subsequently reflected from the peripheral site, and the time point at which these forward and backward propagating waves merge and the amplitude of the reflected (backward) wave affect the level of central BP. The augmentation index (AIx) has been proposed as a measure of the wave reflection, and its clinical usefulness has also been evaluated. In the process, the non-linear relationship between age and AIx, the prognostic value of AIx, and the various effects of antihypertensive drugs on AIx have been shown. However, the clinical usefulness of AIx has not been established, and several questions about its use remain. Future studies will be needed to address these questions, and may contribute to important changes in the management of cardiovascular disease. In this review, we present recent findings on the AIx and discuss the role of this parameter in clinical practice.

The relationship between effective arterial capacitance and pulse wave velocity is dependent on left ventricular stroke volume

BACKGROUND

increased arterial stiffness is a predictor of cardiovascular events. The stroke volume (SV) to pulse pressure (PP) ratio is an estimate of arterial capacitance. Pulse wave velocity (PWV) is a measure of arterial stiffness. This study evaluated the effect of left ventricular (LV) SV on the SV/PP-PWV relationship.

METHODS

97 patients had applanation tonometry and echocardiography to measure arterial capacitance (SV/PP), PWV, and central aortic pressure.

RESULTS

50 patients had normal SV and 47 had low SV. For all patients, PWV inversely correlated with SV/PP. PWV and SV/PP correlated more strongly in the normal SV group than in the low SV group. Aortic PP was significantly correlated with PWV in all patients, in the normal SV group, and in the low SV group.

CONCLUSION

effective arterial capacitance correlates with PWV. The presence of decreased SV weakens the relationship.

Noninvasively determined radial dP/dt is a predictor of mortality in patients with heart failure

BACKGROUND

The left ventricular (LV) developed pressure is a marker of contractility, associated with a poor prognosis during systolic heart failure. The maximal first derivative or slope of the radial pulse wave (Rad dP/dt) has been proposed as a marker of LV systolic function. This study sought to assess the prognostic value of the baseline dP/dt of the radial pulse in patients with heart failure.

METHODS

The Rad dP/dt was noninvasively measured by applanation tonometry, and its effect on mortality was analyzed by using multivariate Cox regression models. We studied 310 consecutive patients. Mean follow-up was 327 +/- 187 days, and 64 patients died or were transplanted during this period.

RESULTS

Death or transplantation was associated with New York Heart Association class III or IV, low systolic or mean blood pressure, low LV ejection fraction, and low Rad dP/dt (634.6 +/- 373.3 vs 730.2 +/- 367.4 mm Hg/s for patients who survived without transplantation, P < .02). A Rad dP/dt <440 mm Hg/s was associated with death or transplantation before and after adjustment for confounding variables (OR [95% CI] 2.19 [1.33-3.58] and 2.88 [1.29-6.38], respectively, P < .01 for both). This relationship was independent of pulse pressure and no significant interaction was found between the Rad dP/dt and the pulse pressure.

CONCLUSION

This study demonstrates, for the first time, that the Rad dP/dt, proposed as a noninvasive peripheral marker of LV systolic function, is an independent predictor of death or transplantation in patients with HF regardless of LV ejection fraction.

Arterial stiffness: clinical relevance, measurement and treatment

Most traditional cardiovascular risk factors alter the structure and/or function of arteries. An assessment of arterial wall integrity could therefore allow accurate prediction of cardiovascular risk in individuals. The term 'arterial stiffness' denotes alterations in the mechanical properties of arteries, and much effort has focused on how best to measure this. Pulse pressure, pulse wave velocity, pulse waveform analysis, localized assessment of blood vessel mechanics and other methods have all been used. We review the methodology underlying each of these measures, and present an evidence-based critique of their relative merits and limitations. An overview is also given of the drug therapies that may prove useful in the treatment of patients with altered arterial mechanics.