Hemodynamic profiles of arterial hypertension with ambulatory blood pressure monitoring.

Blood pressure (BP) measurements obtained during a twenty-four-hour ambulatory blood pressure monitoring (24 h ABPM) have not been reliably applied to extract arterial hemodynamics. We aimed to describe the hemodynamic profiles of different hypertension (HT) subtypes derived from a new method for total arterial compliance (Ct) estimation in a large group of individuals undergoing 24 h ABPM. A cross-sectional study was conducted, which included patients with suspected HT. Cardiac output, Ct, and total peripheral resistance (TPR) were derived through a two-element Windkessel model without having a pressure waveform. Arterial hemodynamics were analyzed according to HT subtypes in 7434 individuals (5523 untreated HT and 1950 normotensive controls [N]). The individuals mean age was 46.2 ± 13.0 years; 54.8% were male, and 22.1% were obese. In isolated diastolic hypertension (IDH), the cardiac index (CI) was greater than that in normotensive (N) controls (CI: IDH vs. N mean difference 0.10 L/m/m2; CI 95% 0.08 to 0.12; p value <0.001), with no significant clinical difference in Ct. Isolated systolic hypertension (ISH) and divergent systolic-diastolic hypertension (D-SDH) had lower Ct values than nondivergent HT subtype (Ct: divergent vs. nondivergent mean difference -0.20 mL/mmHg; CI 95% -0.21 to -0.19 mL/mmHg; p value <0.001). Additionally, D-SDH displayed the highest TPR (TPR: D-SDH vs. N mean difference 169.8 dyn*s/cm-5; CI 95% 149.3 to 190.3 dyn*s/cm-5; p value <0.001). A new method is provided for the simultaneous assessment of arterial hemodynamics with 24 h ABPM as a single diagnostic tool, which allows a comprehensive assessment of arterial function for hypertension subtypes. Main hemodynamic findings in arterial HT subtypes with regard to Ct and TPR. The 24 h ABPM profile reflects the state of Ct and TPR. Younger individuals with IDH present with a normal Ct and frequently increased CO. Patients with ND-SDH maintain an adequate Ct with a higher TPR, while subjects with D-SDH present with a reduced Ct, high PP and high TPR. Finally, the ISH subtype occurs in older individuals with significantly reduced Ct, high PP and a variable TPR proportional to the degree of arterial stiffness and MAP values. There was an observed increase in PP with age in relation to the changes in Ct (see also text). SBP: systolic blood pressure; DBP: diastolic blood pressure; MAP: mean arterial pressure; PP: pulse pressure; N: normotension; HT: hypertension; IDH: isolated diastolic hypertension; ND-SDH: nondivergent systole-diastolic hypertension; D-SDH: divergent systolic-diastolic hypertension; ISH: isolated systolic hypertension; Ct: total arterial compliance; TPR: total peripheral resistance; CO: cardiac output; 24 h ABPM: 24 h ambulatory blood pressure monitoring.

A novel method for the noninvasive estimation of cardiac output with brachial oscillometric blood pressure measurements through an assessment of arterial compliance.

OBJECTIVE: To propose and validate a new method for estimating cardiac output based on the total arterial compliance (Ct) formula that does not need an arterial waveform and to apply it to brachial oscillometric blood pressure measurements (OBPMs). METHODS: One hundred subjects with normal heart anatomy and function were included. Reference values for cardiac output were measured with echocardiography, and Ct was calculated with a two-element Windkessel model. Then, a statistical model of arterial compliance (Ce) was used to estimate cardiac output. Finally, the measured and estimated cardiac output values were compared for accuracy and reproducibility. RESULTS: The model was derived from the data of 70 subjects and prospectively tested with the data from the remaining 30 individuals. The mean age of the whole group was 43.4 ± 12.8 years, with 46% women. The average blood pressure (BP) was 107.1/65.0 ± 15.0/9.6 mmHg and the average heart rate was 67.7 ± 11.4 beats/min. The average Ct was 1.39 ± 0.27 mL/mmHg and the average cardiac output was 5.5 ± 1.0 L/min. The mean difference in the cardiac output estimated by the proposed methodology vs. that measured by Doppler echocardiography was 0.022 L/min with an SD of 0.626 L/min. The intraclass correlation coefficient was 0.93, and the percentage error was 19%. CONCLUSION: Cardiac output could be reliably and noninvasively obtained with brachial OBPMs through a novel method for estimating Ct without the need for an arterial waveform. The new method could identify hemodynamic factors that explain BP values in an ambulatory care setting.