Assessment of Arterials Functions: Is Pulse Wave Velocity ready forprime Time. Gérard M. LONDON INSERM U970 Hopital Georges Pompidou Paris, France

Transcription

1 Assessment of Arterials Functions: Is Pulse Wave Velocity ready forprime Time Gérard M. LONDON INSERM U970 Hopital Georges Pompidou Paris, France

2 The causes of Cardiovascular Diseases in CKD Systolic BP; Diastolic BP Arteriosclerosis Atherosclerosis (Decreased coronary perfusion) Adaptive LVH (Decreased coronary reserve) CORONARY ARTERY DISEASE Volume* Overload *Hgb; AVF; Na+ Maladaptive LVH Systolic/diastolic dysfunction HEART FAILURE SUDDEN DEATH CEREBROVASCULAR PERIPHERAL ARTERY DISEASE

3 Atherosclerosis Arteriosclerosis

4 Flow Flow Pressure Pressure Arterial system as a «conduit» Blood transfer Arterial system as «hydraulic filter» Cyclic high and pulsatile pressure Continuous low pressure Aorta Microcirculation capillaries Cyclic highly pulsatile flow Continuous flow and perfusion

5 Large arteries mechanics Artery as a conduit Artery as a «hydtraulic filter» Diameter Stiffness Wall viscosity Conduction Transduction Transmission Kinetic Energy expenditure Potential Energy storage Potential Energy dissipation Energetic balance of heart-vessel coupling

6 Threshold Decades Years-Months Months-Days healthy subclinical symptomatic Thrombus Intima Media Lumen Plaque

7 Prevalence of discrete plaques on common carotid artery in control subjects and ESRD patients Controls ESRD Age (years) 48.5 ± ± 16 NS Plaques (%) 17.8% 56.3% < 0.01 Type of plaques Calcified 23.1% 91.5% <0.01 Soft/mixed 77% 9% <0.01 London et al Sem Dial 1999

8 Carotid artery calcifications: (longitudinal incidence) Calcified plaque Common carotid artery

9 Carotid artery calcifications: (tranversal incidence) Calcified plaque Common carotid artery

10 Kono K et al. Composition of plaque patter of coronary culprit lesion in CKD KI 2012;82: Green-fibrous Yellow-fatty Red-necrotic White-calcified

11 NC/DC necrotic core/dense calcium AMI-acute myoc.inf; UAP-unstable ang.pect. SAP-stable ang.pect Kono K et al. KI 2012;82:344-51

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14 Ankle-Arm Index as a Predictor of Cardiovascular Disease and Mortality in the Cardiovascular Health Study Newman AB et al for the Cardiovascular Health Study Collaborative Research Group Arteriosclerosis, Thrombosis, and Vascular Biology. 1999;19: Kaplan-Meier survival for 1446 CHS participants with prevalent CVD, by categories of AAI level

15 Ankle systolic blood pressure (mmhg) R=0.95 P< R=0.61 P< Brachial systolic blood pressure (mmhg) - Ankle-Arm index >0.9 - Ankle-Arm index <0.9 G.M London personal data

16 Vintage (months) PTH (pg/ml) ABix >0.9<1.31 Normal ABix <0.9 0 ABix >0.9<1.31 Normal ABix >1.8 Uncompressible ABix >0.9<1.31 Normal ABix <0.9 0 ABix >0.9<1.31 Normal ABix >1.8 Uncompressible

17 Flow Flow Pressure Pressure Cushioning function of arterial system: Arterial system as «hydraulic filter» Cyclic high and pulsatile pressure Continuous low pressure Aorta Microcirculation capillaries Cyclic highly pulsatile flow Continuous flow and perfusion

18 Pressure Diagrammatic representation of pressure-volume relationships Einc=2 Einc=1 dp/dv Volume

19 Blood pressure Blood pressure ARTERIAL FUNCTION AND Pure Conduit Function BP Conduit and Cushioning Function Mean pressure Mean pressure Systole Diastole Systole Diastole

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21 Oxygen Limitation Model Blood Velocity (NOT capillary recuitment) Capillary Transit Time Normally 2-3 seconds O 2 Extraction Smaller Fraction of O 2 Available for Metabolism

22 Time to shoulder (TSh ms) Relationship between the time of appearance of reflected wave on the pressure wave in central artery (time to shoulder - TSh) and aortic pulse wave velocity (PWV) R= p< aortic PWV (cm/s) London et al Hypertension 1992

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24 Pressure wave analysis measured pressure wave forward/incident pressure wave reflected pressure wave pulse wave velocity

25 Role of increased central aortic and pulse pressures in the increase of cardiovascular events Increase in the central pulse pressure that drives cerebral blood flow increased stroke risk Increase chronic kidney disease. PP Increase in left ventricular load (LV load) accelerates increase in LV mass increased risk of LV hypertrophy Decreased Coronary Artery Perfusion Pressure in Diastole increased risk of MI

26 Aortic PWV (ms) Correlation between aortic calcification score and aortic PWV in ESRD patients Abdominal aortic calcification score r = P < Pannier et al. Artery 2007

27 Ca (mmol/kg) Correlation between age and arterial calcium (Ca) concentration in the aorta and internal iliac artery in nonuremic control subjects 400 * Aorta (r=0.84) * * * * * * * * * * * * * * * * **** * * * * Internal Iliac (r=0.75) AGE (years) Ibels et al. Am J Med 1979

28 Briet M et al. KI 2012

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30 3D plot showing the interaction of PWV and age in relation to the global composite cognitive score for the extended regression model Elias, M. F. et al. Hypertension 2009;53:

31 Aortic PWV (m/s) Correlation Between CCr (C-G formula) and Aortic PWV r = 0.30 P< Creatinine clearance (ml/min/m²) Bortolotto et al KI 2001

32 Time to shoulder (TSh ms) Relationship between the time of appearance of reflected wave on the pressure wave in central artery (time to shoulder - TSh) and aortic pulse wave velocity (PWV) R= p< aortic PWV (cm/s) London et al Hypertension 1992

33 CV Survival CV Survival CV Survival 1.00 Aortic PWV 1.00 Brachial PWV 0.75 <9.7m/s >9.7 m/s ²=72.8 P< >12 m/s Follow-up (months) Femoral PWV ²=1.78 P= Follow-up (months) st tertile 2nd tertile 3rd tertile ²=2.34 P= Follow-up (months) Pannier et al Hypertension 2005

34 Carotid tonometry Application of the probe with light pressure on the best palpated pulse. Probe orthogonal to the long axis of the CCA Calibration on MBP and DBP of the RA measure

35 GOOD Applied pressure Holding the probe like a pen, do not smash the gel pad, apply as little Pressure as possible

36 volume Common carotid artery IMT, diameter and stiffness : Walltrack system 150 Pressure (mmhg) D V 7.3 diameter (mm) D P Time pressure < 1 µm IMT 2 D TM RF Signal Spatial resolution µm µm

37 Recent developments in echotracking techniques (Pie- Medical Art.Lab ) Bidimensional RF based IMT measurements

38 Recent developments in echotracking techniques (Pie- Medical Art.Lab ) Distension Diameter IMT Bidimensional RF based Distention profiles

39 X128 RF IMT ± 17 µm Diam ± 35 µm Artlab system : real time, 128 lines RF 4 cm

40 Walltrack system : measurement of flow profiles Velocity (cm/s) Diam

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42 Mechanical stresses in the blood R sq vessel flow Q h circumferential wall stress sq = P x R h fluid shear stress t = 4 µ Q p R 3

43 Arterial remodeling associated with CKD progression Briet M. et al. JASN 2011;22:967 R Circumf. wall stress = Pressure x Radius Thickness

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45 Sensitivity ROC Curve of CV mortality Criterions Age; AUC 72±5% Pulse Pressure; AUC 72±5% Carotid IMT;AUC 68±6% LVmassix; AUC 72±5% 0.25 Calcification score; AUC 82±4% Aortic PWV; AUC 82±4% Specificity Calcification score: cut-off 390;sensitivity 83%;specificity69%; PPV41%;NPV94% Aortic PWV: cut-off m/s;sensitivity 84%;specificity 73%;PPV72%; NPV93%