• Aortic Stenosis: Errors in Echo and Hemodynamic Assessment

    Howard C. Herrmann, MD University of Pennsylvania Philadelphia Disclosure Statement of Financial Interest Grant/Research Support Consulting Fees/Honoraria Major Stock Shareholder/Equity Abbott Vascular Edwards Lifesciences St. Jude Medical Medtronic Gore Edwards Lifesciences St. Jude Medical Paieon Gore Micro Interventional Devices Within the past 12 months, I or my spouse/partner have had a financial interest/arrangement or affiliation with the organization(s) listed below. Affiliation/Financial Relationship Company and EF < 40% (? 35) AHA ACC Guidelines Definition- MG < 30 and LV Dysfunction Hemo assessment with Gorlin (1951) calculation of orifice area assumes- Constant coefficient of orifice contraction at varying transvalvular flow rates Constant coefficient of velocity (energy dissipation due to friction and turbulence) Dependence on accuracy of CO method Echo uses direct measure of Doppler velocity and continuity equation (Koutsurakis, Warth 1984), but assumes- Laminer flow Flat velocity profiles both pre valve and at the orifice Parallel Doppler signal Circular LVOT and accurate measure of LVOT Canine model of chronic AS (22% increase in AVA with 100% increase in flow) Burwash et al, Circ 1994;89-827-835 METHODS 50 patients, mean age 86 yrs, 46% women Echo assess- 2D Doppler, 3D full vol LVOT Cath assess- Dual-lumen catheter for simultaneous gradient CO by TD, Fick with measured VO2, assumed using BSA and LaFarge Statistical comparisons by Bland-Altman, regressions Low flow defined as SV <35 ml/M2 on 3D echo Gertz and Herrmann, 2012, submitted Morin et al, Circ 2003 108-319 SURVIVAL with (I) or without (II) contractile reserve SURVIVAL with or without CAD after surgery Blitz and Herrmann, AJC 1998;81-358 In general, higher operative mortality (16%) and lower long-term survival (50% at 5 years) Levy et al, JACC 2008;51-146-72 Allows assessment of pseudo versus “real” or true AS Normalize / increase transvalvular flow and reassess gradient, AVA How large an increase in gradient or failure to increase AVA is required to demonstrate true AS? Degree of calcification on echo or CT may also be helpful Assess contractile reserve Predicts surgical outcome (prognosis) Does it have similar value for TAVI? TOPAS of 101 pts- AVA < 1.2 and MG < 40, EF < 40 44% had AVR (non-randomized) with trend to improved survival Predictors survival- projected AVA, functional capacity, higher EF Clavel et al, Circ 2008;118-S234 Circulation 2007;115-2856-2864 Low Output, Low Gradient AS With Normal EF Paradoxical low flow (PLF)- AVAI < 0.6 cm2/M2, EF > 50% in 181 of 512 pts (35%) Tended to be older (mean age 70 yrs) and more women High afterload, low SV (< 3.5 ml/M2), small LV High valvular-arterial impedence (Zva) > 5.5 Z va = SAP + MG SVI 55 patients with low EF <40% (mean 29%), but with high gradient Mean age 77 years AVA - 0.5 to 0.8 cm2 Angio EF- 29% to 34% KM survival 60% at 1 year Marked symptomatic improvement occurred in >90% at 2 months unrelated to change in EF Berland et al, Circ 1989;79-1189-1196 Multicenter comparison of 200 surgical AVR and 83 TAVI procedures Def LF LG AS- AVA < 1 cm2, LVEF < 50% TAVI pts had Larger increase in AVA at 12 mos (D 0.8 vs 0.6 cm2) Smaller need for PPM (16% vs 29%) Greater increase in EF (D 14% vs 7%) Limitations Retrospective, non-randomized Various prostheses with potential errors in gradient measurement Patient differences (age, CAD, CABG, AF, NYHA class, effects of surgery) More improvement in EF with TF, though started lower (D18% TF vs 10% TA) Clavel et al, Circ 2010;122-1943-1951 Comparison of 79 pts with LF LG AS (AVA < 1.2 cm2, MG < 40 mmHg, EF < 50%) to 585 pts without LF LG AS Survival was worse in the LF LG AS pts Patients with PPM (EOA < 0.85 cm2/M2) Less LV mass regression Trend to greater mortality Kulik et al, Circ 2006;114-I-553-I-558 In elderly patients, traditional measures of AS severity correlate poorly and using different measures frequently misclassifies critical AS Current guidelines rec invasive assessment only when there is discrepancy between clinical symptoms and non-invasive findings Common in the elderly with diastolic dysfunction, low SV, AF, multiple co-morbidities We recommend 3D-echo as the gold standard for non-invasive assessment TD CO when invasive assessment is undertaken In patients with LF, a less flow dependent measure (eg. resistance) should be considered

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