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Results of the Pr edictors o f Re sp ons e to C R T ( PROSPECT) Trial Chung ES, Leon AR, Tavazzi L, Sun J-P, Nihoyannopoulos P, Merlino J, Abraham WT, Ghio S, Leclercq C, Bax JJ, Yu C-M, Gorcsan J 3rd, St John Sutton M, De Sutter J, Murillo J,. Circulation. 2008;117:2608-2616.
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Results of thePredictors of Response to CRT (PROSPECT) Trial Chung ES, Leon AR, Tavazzi L, Sun J-P, Nihoyannopoulos P, Merlino J, Abraham WT, Ghio S, Leclercq C, Bax JJ, Yu C-M, Gorcsan J 3rd, St John Sutton M, De Sutter J, Murillo J, Circulation. 2008;117:2608-2616.
Introduction • Cardiac Resynchronization Therapy (CRT) improves quality of life and functional status, reduces heart failure related hospitalizations, and prolongs survival in systolic heart failure patients with NYHA Class III or ambulatory NYHA Class IV symptoms and a wide QRS. • Strong clinical mandate for CRT in eligible patients by practice guidelines • Majority of patients treated with CRT show clinical benefit, but some considered non-responders using various measures of clinical responsiveness. • Several echocardiographic measures of mechanical dyssynchrony have identified responders pre-implant Chung, E. Circulation. 2008;117:2608-2616.
PROSPECT Study Purpose: • Prospective, multi-center study designed to evaluate the ability of selected, pre-defined baseline echocardiographic parameters to predict clinical or echocardiographic response to CRT in a prospective, multi center study Primary Endpoints at 6 months: • Clinical Composite Score • Subjective and objective measures of clinical status include: Survival, heart failure hospitalization, change in NYHA Class and change in Patient Global Assessment Score • Definition of Improved: Has not Worsened (death, HF hospitalization, worsening NYHA Class) and demonstrates improvement in NYHA Class and/or improvement in patient global assessment score • Left Ventricular End-Systolic Volume • Definition of Improved: Reduction of ≥ 15% Chung, E. Circulation. 2008;117:2608-2616.
12 Predefined Echo Measures of Dyssynchrony(will report on measures with arrow) • Standard Echo • SPWMDSeptal to posterior wall motion delay (≥ 130 ms) • IVMDInterventricular mechanical delay (≥ 40 ms) • LPEI LV pre-ejection interval (≥ 140 ms) • LVFT/RR LV filling time as % of cardiac cycle length (R-R interval) (≤40%) LLWCLeft lateral wall contraction (any overlap) • Tissue Doppler Imaging • Ts- (lateral-septal)Time Δ between basal lateral and septal peak (≥60 ms) • Ts-SDStandard deviation of time to peak systolic velocity (≥ 32 ms) • PVDPeak velocity difference (≥ 110 ms) • DLC Delayed longitudinal contraction (≥ 2 segments) • TDMaximum difference in time to peak displacement (median) • Ts-peak Maximum Δin time to peak systolic velocity (median) • Ts-onsetMaximum Δin time to onset of systolic velocity (median) Chung, E. Circulation. 2008;117:2608-2616.
Echocardiography Equipment and Core Labs Utilization by Vendor Siemens GE Aloka Philips Chung, E. Circulation. 2008;117:2608-2616.
Training and Quality Control Center • Each enrolling center was trained on protocol and image acquisition, and was accredited by core lab prior to patient enrollment. • Any subsequent studies judged by core lab to be of insufficient quality were censored and not included in the analysis Core Lab • Echo core labs followed internal echocardiographic measurement guidelines created and reviewed by experts and the Steering Committee. • Echo core labs were blinded to CRT response • Independent Echo Review Committee visited core labs to ensure measurement consistency and adherence to protocols prior to statistical analysis Chung, E. Circulation. 2008;117:2608-2616.
Baseline Characteristics Chung, E. Circulation. 2008;117:2608-2616.
% Improved % with ≥ 15% Reduction Ischemic Ischemic Non-Ischemic Non-Ischemic 50% 64% 75% 63% P = 0.01 P = 0.03 Primary Endpoint Results for All Patientsat 6 Months Change in LVESV N = 286 Clinical Composite Response N = 426 Percent of Patients Improved Un- changed Worsened ≥ 15% Reduction Other ≥ 15% Increase Chung, E. Circulation. 2008;117:2608-2616.
Feasibility of Dyssynchrony Measures Chung, E. Circulation. 2008;117:2608-2616.
Primary Endpoint ResultsSelected Echo Measures Clinical Composite Response LVESV P-value P-value 0.44 0.021 0.016 0.013 1.00 0.005 0.27 0.33 0.68 0.79 % Improved % with ≥ 15% Reduction ■Cut-off Met■Cut-off Not Met Chung, E. Circulation. 2008;117:2608-2616.
Philips GE 10 6 London UK Atlanta US Pavia Italy 10 6 Inter-observer Variability LPEI Ts-SD (Yu) SPWMD (Pitzalis) Coef. of Variation: 6.5% Kappa Coefficient: 0.67 Coef. of Variation: 33.7% Kappa Coefficient: 0.15 Coef. of Variation: 72.1% (not displayed) Kappa Coefficient: 0.35 Chung, E. Circulation. 2008;117:2608-2616.
Sensitivity and Specificity: Area Under the ROC Curve • Clinical Composite Response: Range from 0.50 to 0.60 • LVESV: Range from 0.51 to 0.62 Clinical Composite Response Ts-SD AUC = 0.60 LVESV SPWMD AUC = 0.62 Chung, E. Circulation. 2008;117:2608-2616.
Discussion • Dyssynchrony is a complex issue, not a matter of one single measurement. Echo parameters that may be considered attractive candidates for further studies point at different components of cardiac dyssynchrony (inter-, intra-, and A-V dyssynchrony). A general assessment might be warranted. • PROSPECT data may be useful to understand how to better standardize procedures and reduce variability of echo assessment of dyssynchrony. Chung, E. Circulation. 2008;117:2608-2616.
Conclusions The results of the PROSPECT study indicate that no single echocardiographic measure of dyssynchrony, as applied in this multi-center study, may be recommended to further improve patient selection among the CRT candidates. Current clinical criteria including electrocardiogram, remain the standard for CRT patient selection. Chung, E. Circulation. 2008;117:2608-2616.