Intima-Media Thickness

Transcription

1 European Society of Cardiology Stockholm, 30th August 2010 Intima-Media Thickness Integration of arterial assessment into clinical practice Prof Arno Schmidt-Trucksäss, MD Institute of Exercise and Health Sciences Medical Faculty, University Basel

2 The Beginning of a Story of Success Pignoli P Circulation Dec;74(6)

3 Original US Image of IMT Arno Schmidt-Trucksäss

4 Risk Factors Correlated With Carotid Atherosclerosis Cholesterol Triglycerides High-density lipoprotein (inverse relationship) Left ventricular mass Electrocardiographic abnormalities Glucose, glucose intolerance Insulin levels Diabetes (especially type 2) Postmenopausal status High-sensitivity C-reactive protein (women) Fibrinogen (men) Advancing age Male gender Blood pressure (especially systolic) Smoking Body mass index Waist-to-hip ratio Low activity level Race, ethnicity Familial history Genetic factors Alcohol consumption Homocysteine Mancini GBJ et al Circulation 2004;109;22-30

5 Risk Factors Correlated With Progression of Carotid Atherosclerosis Arno Schmidt-Trucksäss Age Smoking CAD Hypertension, Pulse pressure Diabetes, disturbed glucose tolerance LDL-cholesterol Oxidized LDL Triglyceride Lipoprotein (a) Fibrinogene Factor V Leiden Leucocyte count Platelet count and aggregability High sensitive CRP Mancini GBJ et al Circulation 2004;109;22-30

6 Prospective Trials with IMT as a Prognostic Marker Authors Study N Age Follow-up Endpoint Measured region Risk assessment Remark Chambless et Fatal or non-fatal cardio-vascular For IMT > 1 vs. < 1 mm, HR adjusted for Diabetes, HDL-, LDLcholesterol, hypertension, smoking, study center, age and race IMT = mean IMT al ARIC Jahre 4-7 years events CCA.,CB,ICA 1.18 ( ) in men and 1.42 ( ) in women of 6 locations Mean 72.5 years 6.2 years MI, stroke, RR for combined endpoint (adjusted for age, gender, blood pressure (sys, dia), smoking (pack years), diabetes, atrial fibrillation) for maximal IMT CCA: 2.22 ( ) for >1.18 mm O Leary et al. at study im combined (highest) vs. <0.87 mm (lowest IMT quintile); 2.47 ( ) for CHS 4476 entry Median endpoint CCA, ICA >1.81 mm (highest) vs. <0.90 mm (lowest IMT quintile) max. IMT Coronary and max. IMT Iglesias del Sol > years cerebrovascular RR 1.41 (95% CI,1.25 bis 1.82) for stroke and 1.43 (95% CI, 1.16 bis separated by et al Rotterdam 1721 years MW disease CCA, CB, ICA 1.78) for MI region years, HR (adjusted for risk factors) for IMTCCA > 0.79mm vs. < 0.63 mm mean MI, stroke, 1.85 ( ), for IMT CB > 0.79mm vs. < 0.63 mm 1.27 (0.80 Lorenz et al years combined 1.99), for IMT ICA > 0.79mm vs. < 0.63 mm 1.25 ( ) for CAPS 5056 years MW endpoint CCA, CB, ICA combinde endpoint mean IMT far wall

7 CIMT of CCA for Prediction of Future Cardiovascular End Points Arno Schmidt-Trucksäss subjects in eight studies followed for 5.5 years (mean) Absolute CIMT difference of 0.1 mm results in an increase of future risk of : 10 15% for myocardial infarction 13 18% for stroke Lorenz et al Circulation Jan 30;115(4)

8 Implementation of Carotid US into Practice American Heart Association Prevention V Conference persons > 50 years of age at intermediate risk for CVD 34th Bethesda Conference persons at intermediate risk for total CVD event risk assessment by CIMT and CAC to assess atherosclerotic burden ESH and ESC CIMT in hypertensive patients better risk stratification, end-organ damage Greenland P et al Circulation. 2001;104: Wilson PWF et al JACC 2003;41: Mancia G et al J Hypertens 2007;25:

9 Added Value in Risk Stratification on Top of Classical Risk Factors Arno Schmidt-Trucksäss At present it seems that the published evidence to quantitatively support the use of a CIMT measurement to help in risk stratification on top of a risk function is limited. Plantinga Y et al Eur J Cardiovasc Prev Rehabil 2009; 16:

10 Variation of IMT with Age Gender Ethnicity Normal values are difficult to provide

11 Parameters Effecting Measurement Variability Training of sonographers Conditions of examination Imaging protocols Reading protocols

12 Parameters Effecting Measurement Variability Training of sonographers Conditions of examination Imaging protocols Reading protocols

13 SAPALDIA (8 study centers) Aarau Payerne Wald Montana

14 Training of Sonographers in SAPALDIA 3 centralized trainings 1-2 individual trainings Certification Regular Re-Certification

15 Parameters Effecting Measurement Variability Training of sonographers Conditions of examination Imaging protocols Reading protocols

16 Ultrasound examination, practical aspects BP 1 lead ECG Blood pressure cuff right upper arm 10 min rest before exam Temperature C Quiet room Half dark Empty bladder Last meal 2 h before Free neck

17 Parameters Effecting Measurement Variability Training of sonographers Conditions of examination Imaging protocols Reading protocols

18 Where to Measure IMT? Thinner Normal Thicker IMT Reduced visibility Increased IMT Good visibility Carotid bulb Common carotid

19 Anatomical Definition of Carotid Regions Bifurcation ICA CCA ECA Tip of flow divider Opening to the bifurcation -landmark frequently not visible in young subjects

20 Measurement Regions Bifurcation US beam ICA CCA ECA distal proximal

21 Visibility of IM Layer in Different Carotid Segments Espeland M 1996 Montabaun v Swijndregt 1999 Riley W 1992 ICA % Bifurcation % CCA % Espeland M et al Stroke 1996; 27: Montabaun van Swijndregt et al Ultrasound Med Biol. 1999; 3: Riley W et al Stroke 1992; 23:

22 Visibility of Near and Far WalI in Different Carotid Segments Arno Schmidt-Trucksäss ICA Bifurcation CCA % % % Near wall Far wall Percentage of walls in which at least one segment was quantified *. N = 899 participants * More than 50% of 17 sites in each segment Espeland M et al Stroke 1994; 25:

23 Variability of IMT Measurement in Different Regions Location Parameter N Intra- Observer Variability (mm) Inter- Observer Variability (mm) CCA distal 1 cm Max IMT ± ±0.26 Mean IMT ± ±0.24 ICA + Bulb Max IMT ± ±0.69 Mean IMT ± ±0.91 O`Leary et al Stroke 1991; 22:

24 IMT Measurement in Prospective Clinical Trials Bifurcation ECA ICA distal CCA proximal Lorenz M et al Circulation Jan 30;115(4):459-67

25 Common Analysed Segment: CCA far Wall Distal 1 cm Bifurcation US Strahl ICA CCA ECA distal proximal

26 Parameters Effecting Measurement Variability Training of sonographers Conditions of examination Imaging protocols Reading protocols

27 How to Analyse the Images? CCA / Bifurcation CCA Cheng D et al Comp Meth Biomed 2002; 67: 27-37

28 IMT Change Across the Heart Cycle CCA IMT CCA Lumen Normal IMT Increased IMT Analysis by A. Teynor

29 % Measurements Arno Schmidt-Trucksäss Distribution of Max IMTmean Around ECG R-peak % at R-peak R -75ms R-50ms R-25ms R R +25ms R +50ms R +75ms Time (ms) 541 patients Mean deviation from IMT at R-peak = 0.06 mm single images (900 images per patient) Haller C et al Atherosclerosis 195 (2007) e203 e209

30 Sequential Automatic Tracing and Analysis XIMT B-mode virtual M-Mode Teynor a et al submitted

31 Examples of Automatic Detection of IMT Carotid Studio B-mode ArtLab RF-based IMT measurement Bianchini E et al J Ultrasound Med 2010; 29:

32 CIMT Measurement as a Screening Tool for the Assessment of the Atherosclerotic Burden Arno Schmidt-Trucksäss High association with atherosclerotic diseases and events Profound training of sonographers and Standardized measurement and reading protocols needed Potential increase of individual clinical significance based on optimal conditions Thank you!

33 Plaque Definition Focal structure Encroachment into lumen of at least 0.5 mm or 50% of surrounding IMT value or Thickness > 1.5 mm