Load and Function - Valvular Heart Disease Tom Marwick, Cardiovascular Imaging Cleveland Clinic
Indications for surgery in common valve lesions Risks Operative mortality Failed repair - to MVR Operative morbidity Recurrent MR/AR?unnecessary repairs Benefits Reduce mortality Avoid LV damage/chf Avoid atrial fibrillation Improve functional class Valve lesion Load Indication Mitral regurgitation Volume Symptoms, LV size, AF, PHT Aortic stenosis Pressure Symptoms,?valve gradients
The controversy of early surgery in MR Prevalence: 23 35yo 11% (93% mild MR); 65 yrs 30% (27% moderate severe) Cooper HA, Gersh BJ Am Heart J 1998; 135: 925-36
%postop LVD %postop LVD LOAD AND FUNCTION IN VALVULAR HEART DISEASE Are standard resting criteria sufficient? 60 30 50 25 40 20 30 15 20 10 10 5 0 <50 50-54 55-59 >60 Preoperative EF 0 <30 30-34 35-39 40-44 >45 Preoperative LVSD Matsumura et al JACC 2003; 42: 458-63
Pre-operative MR severity
Pre-operative LV function
Pre-operative LV function
Standard resting criteria Criterion Reference LVESD >4.5 cm; LVEF >60% Sarano. Circulation 1994 ESVI > 60 ml/m2 Bonow. Am J Med 1980 LV dp/dt < 1343 mmhg Pai. Circulation 1990 ESWS > 195 mmhg Zile. Am J Cardiol 1985 ESWS/ESVI < 2.6 Carabello. Circulation 1986 Peak elastance slope of LV end systolic P-V loops Starling. JACC 1993
Non-standard LV assessment in MR Measurement of contractile reserve - Ejection fraction - Tissue velocity imaging/strain Myocardial tissue characterization - Prediction of fibrosis - Prediction of post-operative outcome
POST-EX EF = 75% LOAD AND FUNCTION IN VALVULAR HEART DISEASE Accuracy of predictors of post-op LV function % 100 90 Sensitivity Specificity all p < 0.001 REST EF = 60% 80 70 60 83 83 81 80 79 75 65 73 50 ESVI EX EF EX EF LV dp/dt >25 l/m 2 <68% <4% <1000
EF progress and CR Surgical patients EF(%) 90 80 70 EF(%) 60 50 40 30 20 Pre op p=0.006 p<0.0001 6 mo post op p=0.01 p<0.0001 12 mo post op 24 to 36 mo post op Follow up EF in surgically treated CR+ and CR- patients. Comparison of post-up EF between CR+ and CR- patients at 6, 12 and 24 to 36 months resulted in. p=0.008 p=0.16 and, p=0.02 p=0.008 p<0.0001 CR+ CR- 100 90 80 70 60 50 40 30 20 10 p=0.20 p=0.65 p=0.83 p=0.20 Baseline 12 mo 24 to 36 mo CR+ CR- Follow up EF in medically treated CR+ and CR- pts. Comparison of follow-up EF between CR+ and CRpts at 12 and 24 to 36 months resulted in p=0.37 and p=0.06. Lee et al, Heart 2004
Functional capacity (mets) 1.2 LOAD AND FUNCTION IN VALVULAR HEART DISEASE Fig 4: Survival free from cardiac events in CR, survival and functional capacity surgically treated CR+ and CR- patients 18.0 1.0 CR+ 16.0 14.0.8 12.0.6 10.0 8.0.4 Log rank = 4.69 p = 0.03 CR-.2 0 10 20 30 40 50 60 70 80 No at Risk CR+ 19 14 10 6 3 1 CR- 22 16 11 6 3 1 Time from surgery (months) 6.0 4.0 2.0 0.0 Baseline p = 0.05 Follow up Event-free survival post MVR Exercise capacity (medical treatment) Lee et al, Heart 2004
Pre-operative LV deformation
SR and strain as a function of LV diameter A theoretical model of strain rate and strain as a function of ventricular diameter and its relationship with stroke volume. Marciniak A et al. Eur Heart J 2007;28:2627-2636
Asymptomatic MR and Strain Rate Imaging 32 asymptomatic MR pts (NYHA class I to II) Normal Controls (n=22) ExEcho (ΔEF>4%) CR+ (n=22) CR- (n=10) SRI (rest, long axis) ESS (%) SR (1/s)
Strain rate CR+ Strain CR+ 0-0.5-1.0-1.5 Strain rate CR- SR= -1.45/s Strain CR- ESS= - 33% 0-0.5 ESS= - 9% -1.0-1.5 SR= - 0.85/s
SR(1/s) ESS(%) LOAD AND FUNCTION IN VALVULAR HEART DISEASE Strain rate and Contractile reserve CR- CR+ Normal Controls -5-0.5-10 -1-15 -1.5-20 -2-2.5 p=0.008 p=0.95 p=0.002-25 -30 p < 0.0001 p = 0.06 p < 0.0001 Strain rate End-systolic strain Lee R. Am J Cardiol 2004
Sensitivity percent % LOAD AND FUNCTION IN VALVULAR HEART DISEASE Predictors of Contractile Reserve 1 0.9 0.8 0.7 0.6 0.5 ROC curves (AUC) 0.4 Peak SR - 0.86 0.3 0.2 Fx capacity - 0.79 0.1 LVESVexe - 0.75 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1-specificity SR (1/s) Fx capacity (mets) LVESVexe (mls) 100 80 60 40 20 0 SR -1.07 Ex Cap 6.1 METS LVESV exe 43 mls
Non-standard LV assessment in MR Measurement of contractile reserve - Ejection fraction - Tissue velocity imaging/strain Myocardial tissue characterization - Prediction of fibrosis - Prediction of post-operative outcome
37 minimally symptomatic MR pts (NYHA I to II) & normal resting LVEF ExEcho ( EF>4%) CR+ (n=25) CR- (n=12) MV Surgery (n=15) Myocardial Biopsy Fibrosis (n=5) No fibrosis (n=10)
DOPPLER MYOCARDIAL IMAGING IN VALVULAR HEART DISEASE Myocardial strain and fibrosis 1.3 S -1 0.7 S -1
ESS (%) CVIBpw (db) LOAD AND FUNCTION IN VALVULAR HEART DISEASE Predictors of Fibrosis -5-10 8 7 6 p < 0.05-15 -20 5 4 3-25 -30 p < 0.05 2 1 0 Fibrosis No fibrosis
Baseline between pts with and without fibrosis Fibrosis + Fibrosis - bsr -0.98±0.25-1.24±0.27 bess -15.28±5.86-18.11±3.28 b2sr -0.93±0.23-1.13±0.20 b2ess -14.98±3.93-17.91±2.86 Ave_CVIB_aplax 3.31±2.36 6.35±3.89 bascib_mean -13.50±6.99-17.05±6.989 pwcib_mean -18.39±7.93-20.11±8.609
Study Design 73 minimally symptomatic pts (NYHA I to II) with > 3+ Mitral Regurgitation & normal resting LVEF (62 ±5%) 28 females; Age 64 ± 10 years CAD, co-existing MS or aortic valve dis and previous cardiac surgery excluded Exercise Stress Echo Contractile reserve = EF>4% SRI (TVI and 2D-SRI) IB Medical FU (n=30) MV Surgery (n=43) 8±5 months Myocardial biopsy (n=25) F/U Echocardiogram SRI (TVI and 2D-SRI) Fibrosis (n=9) No fibrosis (n=16) LV preservation (n=57) LV deterioration (n=16) Mean deterioration -8±6%
Baseline SRI in pts with normal and impaired LV at F/U N LV function on follow-up LV impairment on follow-up TVI SR 2D-SR /s % 0 TVI ESS 2D-ESS -0.2-4 -0.6-1 -1.4-1.8-1.34-0.97 P<0.0001-1.24-0.90 P<0.0001-8 -12-16 -20-24 -19.9-14.6 P<0.0001-19.3-14.5 P<0.0001 Hanekom L. AHA 2006
Baseline SRI in medical pts with preserved LV Baseline Follow-up TVI SR 2D-SR /s % 0 TVI ESS 2D-ESS -0.2-4 -0.6-8 -1-1.4-1.31-1.25-1.26-1.18-12 -16-20 -20.3-18.7-20.0-19.9-1.8-24 All p=ns Hanekom L. AHA 2006
ROC curves for prediction of impaired LV at F/U TVI SRI Peak systolic strain rate (SR) End systolic strain (ESS) 2D Strain Peak systolic strain rate (SR) End systolic strain (ESS) TVI SR AUC=0.89 Cut-off<-1.1/s TVI ESS AUC=0.84 Cut-off<-17% 2D SR AUC=0.90 Cut-off<-1.0/s 2D ESS AUC=0.84 Cut-off<-17%
Accuracy for prediction of impaired LV at F/U % 100 Sensitivity Specificity 80 60 70 67 81 83 75 80 80 87 80 82 40 20 0 Contr Reserve SR<-1.1/s ESS<-17% 2D-SR<-1.0/s 2D-ESS<-17% Hanekom L. AHA 2006
Indications for surgery in common valve lesions Risks Operative mortality Failed repair - to MVR Operative morbidity Recurrent MR/AR?unnecessary repairs Benefits Reduce mortality Avoid LV damage/chf Avoid atrial fibrillation Improve functional class Valve lesion Load Indication Mitral regurgitation Volume Symptoms, LV size, AF, PHT Aortic stenosis Pressure Symptoms,?valve gradients
Indications for surgery in common valve lesions LVH and LVD are markers of increased risk could LV strain?
Changes in myocardial function with AVR Max. Grad.: 75 mmhg Mean Grad.: 39 mmhg AVA= 0.8 cm² Max. Grad.: 17 mmhg Mean Grad.: 8 mmhg AVA= 2.1 cm² Before AVR After AVR LV EDV: 154 ml LV ESV: 71 ml LV EF: 58 % LV EDV: 169 ml LV ESV: 65 ml LV EF: 62%
Changes in myocardial strain with AVR Long. Strain 11% Long. Strain 17% Before AVR After AVR Circ. Strain 12% Circ. Strain 17%
Changes in myocardial mechanics with AVR Rad. Strain 14% Rad. Strain 34% Before AVR After AVR Net Twist 26⁰ Net Twist 16⁰
Resolution of afterload mismatch Strain recovery improvement of afterload vs resolution of LVH and fibrosis 30 20 10 0 Radial Circumferential Pre Immed post 6m 53 pts with AVR (AS and AR) pre-, 7d and 6m postop Becker M, JASE 2007 73 AVR pts (AS, normal EF) before and 17 m post AVR Delgado V, EHJ 2009
Acute effect of increased afterload Study of 2DS and sonomicrometry (SS) in an exptal pig model of aortic banding Loading conditions: baseline and graded aortic banding (increase in LV pressure of 10, 20, and 40 mmhg) At a low increase in LV afterload, 2D- Srad was still preserved whereas 2D- Slong significantly decreased When LV afterload was subsequently increased, both 2D-Srad and 2D-Slong significantly decreased (by 50-60%) Difference in dependence to wall stress might explain these different behaviors Donal E, EJE 2009
DbEcho for assessment of low gradient AS LV dysfunction (medical Rx) Severe AS (do well with AVR) Ambiguous (bad prognosis) Contractile reserve Valve area Gradient >20% incr WMSI >0.3 cm 2 No change >20% incr WMSI No change No change ± ± Increase Increase in AVA with flow occurs in severe as well as mild AS; use of absolute cutoff >1cm 2 may be better to exclude AS (Carabello) de Filippi CR, Am J Cardiol 1995
Surgical outcome of patients with low output AS Monin, Circulation 2003 Connolly, Circulation 2002
Rest DSI 0.25 20 mcg DSI 0.15
Global strain 7% Global strain 10%
Conclusions Deformation parameters should not be interpreted independent of load Watchful waiting is a reasonable option in asymptomatic severe MR, and deformation parameters can quantify contractile reserve, are a marker of fibrosis and predict LV response to surgery Disturbances of deformation parameters in severe AS are related to intensity of pressure load, so distinguishing the role of intrinsic myocardial disease is more difficult. However, strain may be used to measure contractile reserve.