We respond to recent correspondence relating to the Conduit Artery Function Evaluation study (CAFE), 1 published in Circulation earlier this year.We thank Drs Nieminen, Kahonen, and Kobie for their remarks and suggestions. We agree that increased stroke volume at lower heart rates should be considered as a contributor to the elevated pulse pressure (PP) seen with atenolol-based treatment in the CAFE study. We did not assess stroke volume, and further studies are required to define the impact of blood pressure (BP)-lowering therapies on stroke volume and its contribution to central aortic pressures. Nevertheless, our data do suggest an important role for increased wave reflections in determining higher central aortic pressures with atenolol-based when compared with amlodipine-based treatment. Indeed, the higher central but not brachial PP with atenolol-based therapy in the CAFE study supports the hypothesis that the main driver of differential central aortic pressures was drug effects on pressure wave reflections rather than changes in stroke volume.We agree with Drs Safar and Fournier that the findings of the CAFE study are consistent with their report of differential drug effects on central aortic pressures in the Preterax in Regression of Arterial Stiffness in a Controlled Double-Blind Study (REA-SON). 2 We concur with the view that vascular structural changes are likely to make an important contribution to the long-term hemodynamic effects of BP-lowering therapy, especially wave reflection, and we suggested in our article that different BPlowering treatments may modify central aortic pressures and hemodynamics through differential effects on vascular structure. 1 The fact that the most beneficial effects on central aortic pressure have been observed with vasodilator therapy, in contrast to ␤-blockade, supports the view that a reduction in vascular resistance, by vasodilation and subsequent vascular remodeling, is an important determinant of reduced wave reflection and central aortic pressure, thereby defining the characteristics of optimal BP-lowering therapy.Cameron and colleagues are concerned that the data in their article 3 may have been misinterpreted. We clarify that our reference to their work related to the accuracy and validation of the transfer function rather than the derivation of central aortic pressures, which are prone to and dependent on the same level of inaccuracy as the measurement of brachial BP by cuff sphygmomanometry.We thank Dr Dart et al for their comments and interest in our study but would like to point out fundamental differences between the design and objectives of the CAFE study and The Australian National Blood Pressure Study 2 (ANBP2). substudy of central aortic pressures. 4 The prespecified primary objective 5 of the CAFE study was to examine the hypothesis that 2 different BP-lowering regimens would have different effects on derived central arterial pressures and hemodynamics despite similar effects on brachial pressures. This was convincingly demonstrated by the findings of ...

In the last 30 years several organizations have developed protocols for clinical validation of blood pressure measuring devices. An international initiative was recently launched by the US Association for the Advancement of Medical Instrumentation (AAMI), the European Society of Hypertension Working Group on Blood Pressure Monitoring (ESH) and the International Organization for Standardization (ISO), aiming to reach consensus on a universal AAMI/ESH/ISO validation standard. The purpose of this statement by the ESH Working Group on Blood Pressure Monitoring is to provide practical guidance for investigators performing validation studies according to the AAMI/ESH/ISO Universal Standard (ISO 81060-2:2018), to ensure that its stipulations are meticulously implemented and data are fully reported. Thus, this statement provides: (i) a list of key recommendations for validation studies of intermittent non-invasive automated blood pressure measuring devices according to the AAMI/ESH/ISO Universal Standard, (ii) practical stepwise guidance for researchers performing these validation studies, (iii) a checklist for authors and reviewers of such studies.

BP-lowering drugs can have substantially different effects on central aortic pressures and hemodynamics despite a similar impact on brachial BP. Moreover, central aortic pulse pressure may be a determinant of clinical outcomes, and differences in central aortic pressures may be a potential mechanism to explain the different clinical outcomes between the 2 BP treatment arms in ASCOT.

PP and PWVcf are increased in people with diabetes, but this is not associated with increased AI. These findings conclusively demonstrate that AI is not a reliable measure of arterial stiffness in people with diabetes.

We show that an NPMA with a denominator of one-quarter of the tonometer sampling frequency accurately defines CASP when applied to noninvasively acquired RAPWFs in man. These novel findings have important implications for the simplification of noninvasive CASP measurement and its wider application in clinical trials and clinical practice.

S ystolic and diastolic blood pressure (BP) are important modifiable risk factors for cardiovascular disease.1 Recently, there has been increased interest in the potential predictive value of other parameters derived from the BP waveform. The complex interactions between the heart and the arterial system cause distinctive changes in the BP waveform with aging and disease. Two basic concepts have been advanced to explain these changes: windkessel models and wave transmission models. Windkessel models describe the pressure waveform in terms of a compliant elastic arterial component coupled to an outflow resistance corresponding to the microcirculation. This is a simple and intuitive model of the circulation, but its limitations in systole are well recognized. This approach has been supplanted largely by models based on arterial wave travel.2,3 Westerhof et al 4 devised a method for the separation of arterial waves into their forward and backward traveling components, but the original approach requires the simultaneous measurement of arterial pressure and flow at the same location, which is difficult to perform noninvasively. Studies using proxies for wave reflection, such as central augmentation index (AIx), have not consistently shown associations with major adverse cardiovascular events, 5-8 and a recent metaanalysis 9 found that although increased AIx was associated with increased risk of cardiovascular events overall, there was significant heterogeneity between studies. Recently, we suggested that Abstract-Excess pressure integral (XSPI), a new index of surplus work performed by the left ventricle, can be calculated from blood pressure waveforms and may indicate circulatory dysfunction. We investigated whether XSPI predicted future cardiovascular events and target organ damage in treated hypertensive individuals. Radial blood pressure waveforms were acquired by tonometry in 2069 individuals (aged, 63±8 years) in the Conduit Artery Functional Evaluation (CAFE) substudy of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT). Measurements of left ventricular mass index (n=862) and common carotid artery intima media thickness (n=923) were also performed. XSPI and the integral of reservoir pressure were lower in people treated with amlodipine±perindopril than in those treated with atenolol±bendroflumethiazide, although brachial systolic blood pressure was similar. A total of 134 cardiovascular events accrued during a median 3.4 years of follow-up; XSPI was a significant predictor of cardiovascular events after adjustment for age and sex, and

In the past 30 years, several organizations, such as the US Association for the Advancement of Medical Instrumentation (AAMI), the British Hypertension Society, the European Society of Hypertension (ESH) Working Group on Blood Pressure (BP) Monitoring, and the International Organization for Standardization (ISO), have developed protocols for clinical validation of BP measuring devices. However, it is recognized that science, as well as patients, consumers, and manufacturers, would be best served if all BP measuring devices were assessed for accuracy according to an agreed single validation protocol that had global acceptance. Therefore, an international initiative was taken by the AAMI, ESH, and ISO experts who agreed to develop a universal standard for device validation. This statement presents the key aspects of a validation procedure, which were agreed by the AAMI, ESH, and ISO representatives as the basis for a single universal validation protocol. As soon as the AAMI/ESH/ISO standard is fully developed, this will be regarded as the single universal standard and will replace all other previous standards/protocols.

Cuff BP has variable accuracy for measuring either brachial or aortic intra-arterial BP, and this adversely influences correct BP classification. These findings indicate that stronger accuracy standards for BP devices may improve cardiovascular risk management.