Contribution of arterial excess pressure and arterial stiffness to central augmentation pressure in healthy subjects

Features and implications of higher systolic central than peripheral blood pressure in patients at very high risk of atherosclerotic cardiovascular disease

Peripheral blood pressure (PBP) is usually higher than central blood pressure (CBP) due to pulse amplification; however, it is not well understood why cuff-measured PBP can be lower than CBP estimated by the late systolic pressure of radial pulse waves. We explored the implications of systolic PBP-CBP (P-CBP) differences for cardiovascular (CV) prognosis. In total, 335 patients at very high risk of atherosclerotic cardiovascular disease (ASCVD) underwent automated applanation tonometry and brachial-ankle pulse wave velocity (baPWV), and they were classified into groups according to positive or negative systolic P-CBP differences. Between-group characteristics and clinical outcomes (the composite of coronary revascularization, stroke, heart failure hospitalization, and CV death) were evaluated. Patients with negative differences had significantly higher frequency of hypertension, coronary artery disease, higher ASCVD risk burden, and elevated N-terminal pro b-type natriuretic peptide. They had higher left atrial volume index (LAVI) and lower systolic mitral septal tissue velocity (TVI-s') than those with a positive difference. These patients showed higher systolic PBP and CBP, and a higher baPWV. Multivariable analysis indicated that TVI-s', LAVI, and ASCVD risk burden were independent determinants of such systolic P-CBP differences. During a median follow-up of 12.6 months, clinical outcomes were significantly related to a negative difference (11.5% vs. 3.4%, p = 0.014), and a systolic P-CBP difference ≤ -8 mmHg was associated with a threefold higher likelihood of poor prognosis. In patients at very high risk of ASCVD, systolic P-CBP difference was associated with cardiac dysfunction and ASCVD risk burden, allowing further risk stratification.

Physiological and clinical insights from reservoir-excess pressure analysis

There is a growing body of evidence indicating that reservoir-excess pressure model parameters provide physiological and clinical insights above and beyond standard blood pressure (BP) and pulse waveform analysis. This information has never been collectively examined and was the aim of this review. Cardiovascular disease is the leading cause of mortality worldwide, with BP as the greatest cardiovascular disease risk factor. However, brachial systolic and diastolic BP provide limited information on the underlying BP waveform, missing important BP-related cardiovascular risk. A comprehensive analysis of the BP waveform is provided by parameters derived via the reservoir-excess pressure model, which include reservoir pressure, excess pressure, and systolic and diastolic rate constants and Pinfinity. These parameters, derived from the arterial BP waveform, provide information on the underlying arterial physiology and ventricular-arterial interactions otherwise missed by conventional BP and waveform indices. Application of the reservoir-excess pressure model in the clinical setting may facilitate a better understanding and earlier identification of cardiovascular dysfunction associated with disease. Indeed, reservoir-excess pressure parameters have been associated with sub-clinical markers of end-organ damage, cardiac and vascular dysfunction, and future cardiovascular events and mortality beyond conventional risk factors. In the future, greater understanding is needed on how the underlying physiology of the reservoir-excess pressure parameters informs cardiovascular disease risk prediction over conventional BP and waveform indices. Additional consideration should be given to the application of the reservoir-excess pressure model in clinical practice using new technologies embedded into conventional BP assessment methods.

Total vascular resistance, augmentation index, and augmentation pressure increase in patients with peripheral artery disease

Peripheral arterial disease (PAD) is one of major vascular diseases which frequently coexists with coronary arterial disease and cerebrovascular disease. The patients with PAD have a poor prognosis when it progresses. A new blood pressure testing device enables to simultaneously measure brachial blood pressure (BP), central BP, and several vascular parameters, with easy and non-invasive, in a short time. Here, we aimed to evaluate these arterial stiffness parameters in patients with PAD.In this study, 243 consecutive patients who were suspected of having PAD and referred to our hospital from September 2016 to June 2019, were registered. Several parameters, such as brachial BP, central BP, aortic pulse wave velocity (aPWV), total vascular resistance (TVR), augmentation index (AI) and augmentation pressure (AP), were determined by Mobil-O-Graph. Ankle-brachial pressure index (ABI) was used to define PAD (ABI ≤ 0.9 as PAD). The relationship between PAD and central BP, aPWV, TVR, AI, or AP were investigated.One hundred sixty-two patients (67%) were categorized as the PAD group and 81 patients (33%) as the non-PAD group. In the PAD group, the systolic brachial BP and central systolic BP were significantly higher than those in the non-PAD group (138 ± 24 mmHg vs 131 ± 19 mmHg, P < .05, 125 ± 22 mmHg vs 119 ± 18 mmHg, P < .05, respectively). TVR, AI, and AP were significantly higher in the PAD group (1785 ± 379 dyn s/cm5 vs 1661 ± 317 dyn s/cm5, P < .05, 26.2 ± 13.0% vs 22.2 ± 13.3%, P < .05, 13.5 ± 9.4 mmHg vs 10.7 ± 7.2 mmHg, P < .05, respectively). No significant differences in diastolic BP, central diastolic BP, and aPWV were found between the groups. Multivariate logistic regression analysis revealed that PAD was significantly associated with TVR, AI, and AP (P < .05, respectively).TVR/AP/AI were significantly higher in the PAD group than in the non-PAD group.

C-Reactive protein and soluble intracellular adhesion molecule-1 are related to pulse wave reflection in type 1 diabetes 1C-1

BACKGROUND

The association of inflammation with cardiovascular (CV) complications in diabetes remains a matter of considerable debate. Arterial stiffness and enhanced wave reflection play an important role in CV complications. Therefore, in the present study we investigated whether markers of inflammation are correlated with parameters of wave reflection in type 1 diabetes (T1D).

METHODS

In all, 145 T1D patients were included in the study (median age 32 years, disease duration 10 years, HbA1c 8.2%). Serum concentrations of high-sensitivity C-reactive protein (hs-CRP), matrix metalloproteinase (MMP)-9, soluble intracellular adhesion molecule-1 (sICAM-1), and myeloperoxidase (MPO) were estimated as markers of inflammation. Parameters of pulse wave reflection (central augmentation index [cAIx] and peripheral augmentation index [pAIx]) were assessed using pulse wave analysis.

RESULTS

Multivariate linear regression analysis revealed that, after adjustment for age, mean blood pressure, HbA1c, low-density lipoprotein-cholesterol, and the presence of at least one microangiopathic complication of diabetes, cAIx and pAIx were associated with serum concentration of hs-CRP (β = 1.838, 95% confidence interval [CI] 0.336-3.339 [P = 0.017]; and β = 2.041, 95% CI 0.683-3.400 [P = 0.004], respectively) and sICAM-1 (β = 0.073, 95% CI 0.015-0.131 [P = 0.014]; and β = 0.066, 95% CI 0.013-0.119 [P = 0.016], respectively) in the study group.

CONCLUSIONS

In T1D parameters of wave reflection are related to markers of inflammation.