P214 PREDICTION OF AMBULATORY BRACHIAL CUFF-BASED OSCILLOMETRIC PULSE WAVE VELOCITY USING A NOVEL METHOD FOR ESTIMATING TOTAL ARTERIAL COMPLIANCE

Background and Objective: Total arterial compliance (Ct) serves as a critical determinant of arterial hemodynamics, providing insights into the mechanical and structural characteristics of large arteries and influencing ventricular-arterial coupling. To estimate Ct, we developed a method utilizing data from 24-hour ambulatory blood pressure monitoring (24-h ABPM) recordings. Our objective is to evaluate the reliability of Ct in estimating oscillometric pulse wave velocity (oPWV), with the potential to eliminate the requirement for additional oPWV measurements. Methods: A cross-sectional study was conducted, involving 162 patients who underwent 24-h ABPM, resulting in a total of 8,113 blood pressure (BP) recordings. oPWV was measured during 24-h ABPM using a Custo Screen 310 device (Custo, Ottobrunn, Germany), which has been validated. Ct was estimated employing a two-element Windkessel model based on mean systolic pressure. The formula utilized for Ct estimation was Ct/BSA= (38/PPth)×(4/5)×(Td/T)-(3/7), where BSA denotes body surface area, Td represents diastolic time, T signifies the cardiac period, and PPth denotes theoretical pulse pressure. A linear regression model (LRM) was developed to estimate oPWV from Ct. Results: Among the participants, 55.1% were men, with an average age of 55.7±16.2 years and a body mass index of 27.4±3.7 kg/m 2 . The analyzed records revealed an average systolic blood pressure of 125.6±18.7 mmHg, diastolic blood pressure of 79.5±12.2 mmHg, heart rate of 71.0±12.2 beats per minute, Ct of 0.9±0.3 mL/mmHg, and oPWV of 7.2±1.8 m/s. The best predictive model (R 2 =0.42; r=0.65) for oPWV was based on the ratio of systolic time (Ts) to Ct as follows: oPWV=3.3 × 6.0 ×[Ts/(Ct/BSA)]. Indexed Ct demonstrated an inverse relationship with oPWV (Figure). Residuals analysis confirmed compliance with assumptions. Conclusions: The Ts/Ct ratio inversely predicts oPWV, indicating an inverse relationship between Ct and oPWV in this population. These findings suggest that estimated Ct has the potential to replace oPWV in clinical practice for cardiovascular risk stratification.