Low Gradient AS Normal LVEF Shahbudin H. Rahimtoola MB, FRCP, MACP, MACC, FESC, D.Sc.(Hon) Distinguished Professor University of Southern California Griffith Professor of Cardiology Professor of Medicine Keck School of Medicine at USC Chief Physician I: LAC + USC Medical Center Oregon 2014 Pt. No. MSG CI LVEF 11 20 1.1 0.20 12 21 1.3 0.21 13 23 2.3 0.23 14 25 1.3 0.15 Mean ± SE 22 ± 1 1.5 ± 0.3 0.20 ± 0.02 Carabello B et al, Circulation 1980; 62:42-48 Severe AS + Low Mean AV Gradient (<30 mm Hg) + LV Dysfunction (LVEF <0.35) 3-year survival 62% Of Survivors 77% NYHA FC I / II LVEF Improved by 0.10 ± 0.14 In Op. Survivors: 8% Annual Mortality 1 Connolly HM et al. 2000;101:1940-46
Percentage of LV Stroke Loss Tobin JR, Rahimtoola SH, Blundell P, Swan HJC Circulation 1967;35:868-879 %LVSWL = MSG LV-sm X 100 Severe AS; n=103; Age 72±11 yrs Saito T et al. AJC 2012;110:93-97 Grading Severity of AS 19 Studies of Natural History (1) 2 Subsequent Studies (2) Severe AS is AVA <1.0cm 2 (1)Rahimtoola SH. JACC 1989;14:1-23 (2)Rahimtoola SH. An Era in Cardiovascular Dis.: Elsevier 1991;Update of JACC 1989 2
Aortic Stenosis Shwarz F et al. Circulation 1982;66:1105-1110 Horskotte D., Loogen F. Eur Heart J 1988;9[suppl E]:57-64 A SUGGESTED GRADING OF THE SEVERITY OF AORTIC STENOSIS Aortic Stenosis AVA, cm 2 AVA Index, cm 2 /m 2 Mild >1.5 >0.9 Moderate >1.0 to 1.5 >0.6 to 0.9 Severe <1.0** <0.6 Very Severe/Critical + <0.7 <0.4* ** Patients with AVA s that are borderline values between the moderate and severe grades (0.9-1.1cm 2 ;0.55-0.65 cm 2 /m 2 ) should be individually considered. ** Rahimtoola SH. JACC 1989;14:1-23 Tobin JR et al Circulation 1967;35:868-79 * Rahimtoola SH. Eur Heart J 2008;29:1783-90 + Morrow AG et al. Ann Intern Med 1968;69:1255-86 Patient More Recently ECHO/Doppler AS: Severe Clinical Evaluation History Physical Examination ECG Chest X-ray R & L Heart Cardiac Cath. LV and Coronary Angiography 3 Not Severe AS AS: Severe Obstructive CAD Clinical Follow-up AVR CABG
What Has Happened After 2000? No data on clinical assessment Focus and reliance on: Echocardiography/Doppler Gradients Guidelines Guidelines Criteria for Severe AS ESC/EACTS * ACC/AHA AVA (cm 2 ) <1.0 <1.0 AVAi (cm 2 /m 2 ) <0.6 - Mean AVG (mmhg) >40 >40 Maximum jet velocity (m/s) >4.0 >4.0 Velocity ratio <0.25 - * Vahanian A et al. EHJ 2012;33:2451-96 Bonow RO et al. JACC 2008;52:e1-142 European Society of Cardiology Valve area alone with absolute cut-off points cannot be relied upon for clinical decision making and it should be considered in combination with flow rate, pressure gradient and ventricular function, as well as functional status. AS with a valve area,1.0 cm 2 is considered severe; however, indexing to BSA, with a cut-off value of 0.6 cm 2 /m 2 4 Guidelines on the management of valvular heart disease, European Heart Journal (2007) 28, 230 268
ECHO/Doppler AS: Absent AS: Mild/Moderate AS: Severe High Gradient (HG) Normal Flow (NF) Low Flow (LF) Low Gradient Normal Flow (NF) Low Flow (LF) Arbitrary Values Low Flow <35 ml/m 2 Low Gradient <40 mmhg Issues to be Considered Blood Flow Mean Valve Gradient Aortic Valve Area 5
Stroke Volume by 2DE BENEFITS: NON-INVASIVE, PRACTICAL, EASILY EMPLOYED PITFALLS: INHERENT ASSUMPTIONS AND SIMPLICATIONS LVOT cross-section assumes circular shape Values are squared LVOT velocity employs different window as LVOT area measurement Flow velocities varies within LV outflow. Values are thus dependent on position of pulse wave Doppler sampling area. Is also angle-dependent Mild LVOT obstruction upper septal hypertrophy Issues to be Considered Blood Flow Mean Valve Gradient Aortic Valve Area Formula for AVG, DP = 4V 2 Is a simplification of the Bernoulli Equation P 1 - P 2 = ½p(V 22 ) + p 2 2 DV/DT DS + R(V) Convective Acceleration Flow Acceleration Viscous Acceleration Eliminates: Flow acceleration, Viscous Friction Factors Ignores proximal velocity 6 H. Feigenbaum Echocardiography, 5th Ed., 1993, p. 195-196
Other Issues with AV Gradients by ECHO/Doppler Energy losses Non-uniform velocity profiles Omission of upstream velocity Gradients assessed at valve level Gradient after pressure recovery is more meaningful for the circulation In patients: With high cardiac output With small annuli and Those with eccentric orifice Feigenbaum: Echocardiography 5 th Ed. Rijsterborgh H. Ultrasound Med Biol 1987;3:241-84 Niederberger J et al. Circulation 1996;94:1934-40 Rahimtoola SH JACC Img 2010;3:563-6 7 Lauten, J. JACC 2013;61:1799-808
Figure 1B indexed aortic valve area (cm 2 /m 2 ) 0.8 0.6 0.4 0.2 16% 0% 2% 1% cardiac catheter echocardiography 34% 50% 38% 59% 0 20 40 60 80 100 mean pressure gradient (mmhg) 120 Minners J et al. Heart 2010;96:1463-1468 Olmsted County, MN is Community Practice of Mayo Clinic Whose Personnel Perform All Cardiology Services N=360; Age: 74 ± 14 yrs Of pts with severe AS (LVEF >0.50) 67% had mean AV gradient <40 mmhg 32% had mean AV gradient <30 9% had mean AVG >40 mmhg Eventually 131 pts had AVR Reasons AVR not performed: Low gradient 57% Equivocal Symptoms 43% Co-Morbidities 37% Refused surgery 20% Physician Choice 20% Malouf J et al. JTCVS 2012;144:1421-7 Eventually 131 (45%) with AVA <1.0 cm 2 ultimately had AVR with: Mortality OR 0.61; 95% CI 0.39-0.94 (p=0.02) HF OR 0.29;95% CI 0.13-0.64 (P<0.01) Malouf J et al. JTCVS 2012;144:1421-7 8
Severe AS n=2427; Echo s n=3483; 1994-2004 Normal LV Function; AVA <2cm 2 Guidelines/ Recommendations Parameter Patients with Severe stenosis AHA/ACC AVA <1.0 cm 2 69% ESC AVA/BSA <0.6 cm 2 76% Otto V max >4.0 m/s 45% AHA/ACC P m >40mmHg 40% Minners J et al. EHJ 2008;29:1043-8 Rastogi A, et al. Heart 2014;6:445-446 Issues to be Considered Blood Flow Mean Valve Gradient Aortic Valve Area 9
Poh KK et al. EHJ 2008;29:2535 ECHO/Doppler AS: Absent AS: Mild/Moderate AS: Severe AVA <1.0 cm 2 AVAi <0.6 cm 2 Mean AVG >40 mmhg Jet Velocity >4ms Velocity ratio >0.25 High Gradient (HG) Normal Flow (NF) Low Flow (LF) Low Gradient (LG)_ Normal Flow (NF) Low Flow (LF) Flow-Gradient, Severe AS, P:LVEF Jan 1, 2006 Dec 31, 2011 (Mayo Clinic) Pts with AS 14,656 Not severe AS (AVA >1 cm 2 ) 9,558 (65%) Reduced LVEF (<0.50) 2,231 (15%) >1 concomitant Mod VHD lesions 1156 (7.9%) Supra valve or subaortic AS 5 Flow gradient patterns in 1704 (11.6%) 10 Eleid MF et al. Circulation 2013;128:1781-89
Flow Gradient Patterns: n=1704 Group 4 NF/HG (77 ± 12 yrs) 1249 (73%) Group 3 NF/LG (80 ± 11 yrs) 352 (21%) Group 2 LF/LG (77 ± 12 yrs) 53 (3%) Group 1 LF/HG (76 ± 12 yrs) 50 (3%) Excluding patients with associated VHD LVEF > 0.50 70% (1193/1704) were symptomatic Eleid MF et al. Circulation 2013;128:1781-89 Events During Follow-Up: [n(%)] Group 1, LF/HG (n=50, 3%) Group 2, LF/LG (n=53, 3%) Group 3, NF/LG (n=352,21%) Group 4, NF/HG (n=1249, 73%) Surgical AVR 29 (58) 26 (49) 141 (40) 861 (69) Concomitant CABG Transcatheter AVR Balloon valvuloplasty 9 (18) 12 (23) 63 (18) 289 (23) 5 (10) 1 (2) 7 (2) 51 (4) 3 (6) 1 (2) 7 (2) 36 (3) Death 14 (28) 24 (45) 80 (23) 262 (21) Eleid MF et al. Circulation 2013;128:1781-89 62% (1057/1704) had S:AVR Flow Gradient Patterns in Severe AS Overall, AVR was associated with 69% reduction in risk of death; HR 0.31;95% CI 0.25-0.39, P<0.0001 AVR conferred a strong survival benefit in LF/LG and NF/HG patients 11 Eleid MF et al. Circulation 2013;128:1781-89
Symptomatic Pts. Propensity Matched AVAi <0.6 cm 2 /m 2 Mean AVG <40 mmhg Stroke Index (ml/m 2 ) AVR 36 ± 8 Med 34 ± 9 Ozkan A et al. Circulation 2013;128:622-631 HR 0.54 (95% CI 0.32-0.94) Flow-Gradient Patterns in Severe Aortic Stenosis Eleid MF et al. Circulation 2013;128:1781-89 Problems with Study Criteria for Severe AS: AVA<1.0cm 2 Criteria for selection to offer AVR Death: Before AVR After AVR No data on CAD No data on Rx for co-morbid conditions A certain % ABV Flow is per beat and not C.O. 12
Areas of Concern: 1 Inadequate information about patient evaluation initially Significant problems with ECHO/Doppler findings Guidelines: Have criteria that are inconsistent Are largely consensus statements/recommendations Areas of Concern: 2 Outcomes have serious implications for the patient. For example: a) Implanting a PHV in a patient who does not need it; and b) Not implanting a PHV in a patient who needs it (probably even if asymptomatic) SHORTENS HIS/HER LIFE Patient More Recently ECHO/Doppler AS: Severe Clinical Evaluation History Physical Examination ECG Chest X-ray R & L Heart Cardiac Cath. LV and Coronary Angiography 13 Not Severe AS AS: Severe Obstructive CAD Clinical Follow-up AVR CABG
Severe AS By Cardiac Catheterization: AVA <1.0 cm 2 AVAi <0.6 cm 2 /m 2 14