PWV & PWA Parameter Extraction / Transfer Function

1. PWV & PWA Parameter Extraction / Transfer Function

2. Sensors PWV Transfer Function Parameter Extraction Femoral PWA Dorsalis Carotid Radial Diagnosing Cardiovascular Disease Pulse waves from superficial arteries Diagnosis of vascular Disease using pulse waves Different shapes of waveforms

3. PWV (Pulse Wave Velocity) Young normal aorta Old stiff 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

4. PCG Sensor Carotid artery ECG Electrode Radial artery PTT1 PTT2 Femoral artery Dorsalis Pedis artery Distance PTT1 PWV = PWV (Pulse Wave Velocity) 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 High PWV reflects arterial aging caused by decreasing arterial elasticity and increasing systolic pressure

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

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

7. Importance of Central Blood Pressure 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 ASCOT(Anglo-Scandinavian Cardiac Outcomes Trial) CAFE(conduit artery function evaluation)

8. Forward and Reflected Pressure Pulse forward wavefrom the heart reflectedfrom bifurcation

9. Central Aortic Pulse (Young Elastic Artery) Resistance artery

10. Central Aortic Pulse (Old Stiff Artery) Resistance artery

11. Aortic Aortic 150 150 140 140 130 130 120 120 (mmHg) (mmHg) 110 110 100 100 90 90 80 80 70 70 0 0 100 100 200 200 300 300 400 400 500 500 600 600 700 700 800 800 900 900 1000 1000 (msec) (msec) Systole Systole Diastole Diastole Central Aortic Pulse • 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

12. AG : Augmentation PP : Pulse Pressure AIx (Augmentation Index) • 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

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

14. Transfer Function Transfer Function Clinical Evaluation

15. System Characterization & ARX Model • General-linear polynomial model • ARX model

16. Clinical Evaluation RADI pressure wire SBP Analysis system PP