PWV & PWA Parameter Extraction / Transfer Function

Dorsalis Carotid Radial Femoral Pulse waves from superficial arteries Different shapes of waveforms PWV PWA Diagnosis of vascular Disease using pulse waves Diagnosing Cardiovascular Disease

Old stiff aorta Young normal aorta - flow wave : flow of the blood itself - doppler - diameter wave : diameter change (volume change) of the artery – Infrared - pressure wave : waveform through the arterial wall – pressure sensor PWV (Pulse Wave Velocity)

High PWV reflects arterial aging caused by decreasing arterial elasticity and increasing systolic pressure PWV (Pulse Wave Velocity) : Velocities of Pulse waves traveling through the arterial wall between two recording sites  provides useful noninvasive index for diagnosing arterial aging and stiffness PTT 2 PTT 1 Distance PTT 1 PWV = ECG Electrode PCG Sensor Femoral artery Dorsalis Pedis artery Carotid artery Radial artery PWV (Pulse Wave Velocity)

Algorithm for detecting upstroke point –Assign threshold –1 st differential maximum amplitude –2 nd differential maximum amplitude –intersecting tangent method Feature Extraction

Patient’s DB PWV values Feature extraction Calculation of PWV Values

A Study for the comparison of newly developed medicines Atenolol/Bendroflumethiazide vs. Amlodipine/Perindopril New medicine reduced the fatal and non-fatal Stroke up to 23% New medicine reduced the death rate caused by cardiovascular disease and myocardial infarction up to 16% However, there were no differences in the Brachial Blood Pressure values CAFE (conduit artery function evaluation) ASCOT (Anglo-Scandinavian Cardiac Outcomes Trial) Importance of Central Blood Pressure

forward wave from the heart reflected from bifurcation Forward and Reflected Pressure Pulse

Resistance artery Central Aortic Pulse (Young Elastic Artery)

Resistance artery Central Aortic Pulse (Old Stiff Artery)

Increased Left Ventricular Load (LV) The area under the pressure-time curve during systole is by definition of LV load Increase in LV load accelerates increase in LV mass and increases risk of LV hypertrophy Reducing the Coronary Artery Pressure The pressure that is perfusing the coronary arteries during the critical diastole period is reduced increasing the risk of myocardial ischemias (mmHg) Aortic SystoleDiastole (msec) (mmHg) Aortic SystoleDiastole (msec) Central Aortic Pulse

Definition : Aix(%) = AG/PP*100 Algorithm : Augmentation Index is defined as the first zero crossing from positive to negative of the fourth derivative and occurs 55ms after onset of systolic pressure AG : Augmentation PP : Pulse Pressure AIx (Augmentation Index)

Negative slope and zero-crossing 55msec after the upstroke point Extraction of AIx Point 4 th Derivatives a: systolic peak b: augmentation point d: dicrotic notch 1 st Derivatives after the systolic peak

Clinical Evaluation Transfer Function

System Characterization & ARX Model General-linear polynomial model ARX model

RADI pressure wire Analysis system SBP PP Clinical Evaluation