P072 VALIDATION OF A NOVEL METHOD FOR NONINVASIVE ESTIMATION OF CARDIAC OUTPUT USING BRACHIAL OSCILLOMETRIC BLOOD PRESSURE MEASUREMENTS IN PATIENTS WITH VARIOUS CLINICAL CONDITIONS

Background and Objective: Estimating cardiac output (CO) and other hemodynamic parameters from blood pressure (BP) measurements could aid in selecting appropriate antihypertensive treatments in clinical settings. Our research group has developed a non-invasive method to estimate CO based on total arterial compliance (Ct). However, its validity in populations with various cardio-metabolic chronic diseases remains uncertain. The objective of this study is to assess the validity of our CO estimation method across different patient with varied clinical conditions. Methods: A cross-sectional study was conducted involving 217 adult patients who underwent ambulatory transthoracic Doppler echocardiograms, irrespective of valvular or cardiac pathology, or medication use, provided they had normal aortic valvular anatomy. Stroke volume was calculated as the product of the cross-sectional area of the aortic annulus and the average velocity of the left ventricular outflow tract. Simultaneously, oscillometric BP measurements were obtained. Subsequently, the CO values obtained via Doppler echocardiography and those estimated based on Ct were compared to determine validity. Ct was estimated as: Ct/BSA= 38/PPth + 4/5 × Td/T - 3/7, where BSA denotes body surface area, Td signifies diastolic time, T represents the cardiac period, and PPth refers to the theoretical pulse pressure. Results: Of the participants, 49.7% were men, with an average age of 54.0±14.0 years. Among them, three had a history of acute myocardial infarction, one had a pacemaker, nineteen were diabetic, and one hundred thirty-six were hypertensive. CO by echocardiography averaged 4.9±1.0 L/min, ranging from 2.0 to 8.5 L/min. The agreement of CO between the new method and Doppler echocardiography was good. Bland-Altman plots showed that the differences between the methods were randomly distributed along the mean difference line (Figure). Conclusions: The novel method for noninvasive estimation of CO based on Ct with brachial oscillometric BP measurements in patients with various clinical conditions is deemed valid. Its implementation in clinical practice has the potential to transform patient assessment.