Left Atrial Volume:?Physiologic Model for Cardiovascular Disease Risk. Dr Gitura Muriuki Physician Kenyatta National Hospital
Aging Epidemic US approx 35m 65yrs plus. Fastest growing cohort 80s. Comorbidities & disabilities Successful/ healthy aging? Aging synonymous with disease? Subclinical disease.
Aging Epidemic The strata that dies before its time falls victim to an artificial epidemic N.M. Hadler,MD Arch Int Med 2003;163:1261
A man is as old as his arteries Thomas Sydenhan
Age and Brachial Pulse Pressure Increase with age. Strong,independent predictor of M/M in general pop,htn,chd,esrd. Age-associated increase in IM thickening is accompanied by both luminal dilatation and a reduction in compliance or distensibility, with an increase in vessel stiffness. Circ 2003;107:139 Framingham 1997
Age and Atrial fibrillation Highly prev age related. 84% of pts with AF > 65yrs. HF,QOL,hospitalization,stroke,doubles all cause & CV mortality. LA volume predictor of AF in the elderly. Arch Int Med 1995;155:469 Mayo Clin Proc 2001;76:467
Age and stroke Incidence incr with aging pop. Death,disability,severe neurologic disability, poor QOL,and incr social economic burden. Stroke 1999;39:2523-2528
Clustering of CV Disease and Risk USA Death CV Epidemic 1. CHF 2. Stroke CHF Coronary Disease 1. CHF 2. AF 3. Cancer 4. Dementia Atrial fibrillation Digestive dis Cause? Stroke Hypertension SBP PP 3. Metabolic Syndrome 4. Degenerati ve valve dis Metabolic Syndrom (type II diabetes, Obesity) Sleep disorder breathing Erectile Dysfunctional Cancer Dimentia
Cause of clustering? a good metaphor implies intuitive perception of the similarity in dissimilars. Aristotle
Biological Properties of the Mammalian Myocardium increases or decreases in the demands placed upon the heart are accompanied by changes in cardiac size,composition and function Circ Res 1984;54:367-377
Forward continuity Disease. Forward Remodeling Coduit Vessel Stiffening. Increased PWV, PP, BP Muscular arteries Capillary J AM Coll Cardiol 2001; 37: 975 Microvasc End Organ
Backward continuity Disease Ventricle Atria Veins Conduit Vessel Stiffening Reverse Remodeling J AM Coll Cardiol 2001; 37: 975-984
Atrial and Pulmonary Vein Stretch LV diastolic dysfunction Continuity Disease J Cardiovasc Electrophysiol 11:623,2000
Cardiac Function Left atrial volume (LAV) is to diastolic function, as glycosilated hemoglobin is to diabetes. >>duration and magnitude of diastolic dysfunction J.Seward,MD mayo Clinic,2000
LAV how to measure 1. Biplane A-L method 2. Simpson s disc summation 0.85xapical 4ch area x apical long axis area Left atrial length
LA Volume Index = constant Indexed LA volume 22 6 Not change with normal aging J Am Soc Echocardiography 2003;16:1049 Am J cardiol 2002;90:1284 Chest 1984;84:595 Am J Cardiol 1983;51:336
Diastolic Dysfunction Filling pressure LA exposed to LV Elevated FP = increase LA pressure Uniformly abnormal with HF Precedes onset of risk factors e = myocardial relaxation abnormal LA volume = Chronicity DD E/e = Acuity DD
Risks for AF & CHF >65yrs HF, AF Death LAV < 27 cc/m 2 LAV 27-37 cc/m 2 LAV >37 cc/m 2 Tsang Am J Cardiol 2004; 93: 54-58
First AF and LAVI 8% 12% 15% 26% Mayo Clin Proc 76:467, 2001
2 Year Survival: AMI Acute MI variables affecting survival Circulation 2003; 107:2207-2212
Postop AF and LAVI <32ml/m 2 65yr n = 25 <32ml/m 2 >65yr n = 25 >32ml/m 2 65yr n = 55 >32ml/m 2 >65yr n = 98 80% JACC 2006: 48:779-786
LAV over time for 23 pts with lone Af without events Osranek, M. et al. Eur Heart J 2005 26:2556-2561 Copyright restrictions may apply.
Reclassification of AF Copyright restrictions may apply. Osranek, M. et al. Eur Heart J 2005 26:2556-2561
Correcting Misclassification of AF Osranek, M. et al. Eur Heart J 2005 26:2556-2561 Copyright restrictions may apply.
Physiological Risk Modeling 90% 0-4 Age (65-85) 1 Male gender 1 Diabetes 1 HTN > 140 2 LVEF < 50% 1 LA Vol Index 1Diastolic dys 1 LV mass (>120g/M 2 ) Risk score low < 2 3 4 Medium >5 High 74% 50% Tsang JACC 2003;42:1199
LAVI:Novel Biomarker Reclassifies:Physiological AF defiition Primary AF(Normal diastolic function) Secondary AF(Increased filling pressure) Superior risk model (compared to FS) Change management( 1 o vz 2 o AF) Risk stratifier in subclinical CV disease Monitor Risk Change?
Physiological Risk Model Normal Benign Volume Overload Mild Severity Mod Severity High Severity LAVI (cc/m 2) 22 6 Large >28 28-33 34-39 40 e cm/s 12 Nomal 12 10 <10 <10 E/E' <8 NA >8-10 8-14 15 J Seward MD
Risk risk reduction based on Risk Factors Is based on association & probability; Physiological Model is based on cause & effect J. Seward and T. Tsang Mayo Clinic,2002
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