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Mechanical Dyssynchrony Defined by Phase Analysis from GSPECT:. Does It Predict Mortality?. Paul L. Hess, MD; Linda K. Shaw, MS; Robert Clare, MS; Mary L. Shepherd, CNMT; Michael MacKenzie, MS; Robert Pagnanelli, BSRT, CNMT, NCT; Mona Fiuzat, PharmD; Jonathan P. Piccini, MD, MHS;
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Mechanical Dyssynchrony Defined by Phase Analysis from GSPECT: Does It Predict Mortality? Paul L. Hess, MD; Linda K. Shaw, MS; Robert Clare, MS; Mary L. Shepherd, CNMT; Michael MacKenzie, MS; Robert Pagnanelli, BSRT, CNMT, NCT; Mona Fiuzat, PharmD; Jonathan P. Piccini, MD, MHS; Sana M. Al-Khatib, MD, MHS; Christopher M. O’Connor, MD; and Salvador Borges-Neto, MD
Cardiac Resynchronization Therapy (CRT) • Selection criteria • Reduced ejection fraction (< 35%) • New York Heart Association Class I-IV • QRS duration > 120 ms • One third of recipients do not benefit.
Phase Analysis by GSPECT MPI Dyssynchrony measures • Standard deviation • Bandwidth Chen J et al. Assessment of Left Ventricular Mechanical Dyssynchrony by Phase Analysis of ECG-gated SPECT Myocardial Perfusion Imaging. J Nucl Cardiol 2008; 15: 127-36.
Prevalence of Dyssynchrony by GSPECT MPI 71% 56% 52% 39% 31% Samad Z et al. Prevalence and Predictors of Mechanical Dyssynchrony as Defined by Phase Analysis in Patients with Left Ventricular Dysfunction Undergoing Gated SPECT Myocardial Perfusion Imaging. J Nucl Cardiol 2011; 18: 24-30.
Objective To determine whether mechanical dyssynchrony detected by phase analysis of GSPECT MPI can identify patients with coronary disease at increased risk of all-cause mortality and/or cardiovascular mortality.
Data Source Duke Databank for Cardiovascular Disease Study Population (n=1,434) Angiographically significant coronary disease GSPECT MPI between July 2003 and August 2009 Stress testing Exercise treadmill testing was preferred
Dyssynchrony Measurement Emory Toolbox Software (Atlanta, GA) programs were used to assess mechanical dyssynchrony Statistical Analysis Cox proportional hazards modeling • Unadjusted • Adjusted for standard clinical covariates • Adjusted for above and LV function Kaplan-Meier survival analysis
Baseline Characteristics (n=1,434)* *Data are presented as % unless otherwise specified.
Outcomes Associated with Bandwidth* *Per 10° increment †Adjusted for age, sex, race, chronic obstructive pulmonary disease, diabetes mellitus, hypertension, peripheral vascular disease, cerebrovascular disease, prior myocardial infarction, congestive heart failure, renal insufficiency, and tobacco use ‡Adjusted for above and left ventricular ejection fraction
Outcomes Associated with Phase SD* *Per 10° increment †Adjusted for age, sex, race, chronic obstructive pulmonary disease, diabetes mellitus, hypertension, peripheral vascular disease, cerebrovascular disease, prior myocardial infarction, congestive heart failure, renal insufficiency, and tobacco use ‡Adjusted for above and left ventricular ejection fraction
Outcomes Associated with Bandwidth By LVEF* *Per 10° increment †Adjusted for age, sex, race, chronic obstructive pulmonary disease, diabetes mellitus, hypertension, peripheral vascular disease, cerebrovascular disease, prior myocardial infarction, congestive heart failure, renal insufficiency, tobacco use, and left ventricular ejection fraction.
All-Cause Death Over Time Stratified by Left Ventricular Function and Bandwidth EF < 35%, BW > 100 EF < 35%, BW < 100 P=0.604 EF > 35%, BW > 100 EF > 35%, BW < 100 Proportion dead P<0.001 Years
Cardiovascular Death Over Time Stratified by Left Ventricular Function and Bandwidth EF < 35%, BW > 100 EF < 35%, BW < 100 EF > 35%, BW > 100 P=0.783 EF > 35%, BW < 100 Proportion dead P<0.001 Years
Implication Principal Finding Mechanical dyssynchrony detected by GSPECT MPI is an early marker of all-cause and cardiovascular mortality among patients with LVEF >35%. Patients with LVEF > 35% who do not meet current criteria for CRT may nonetheless benefit from device placement.
Limitations Limited number of patients with reduced EF Retrospective, observational study design Sampling bias Diagnostic bias Presence of LBBB unknown
Conclusions Mechanical dyssynchrony detected by phase analysis of GSPECT MPI can identify patients with coronary disease at increased risk of all-cause mortality and/or cardiovascular mortality after adjustment for standard clinical covariates exclusive of left ventricular ejection fraction. Phase bandwidth is associated with adverse outcomes among patients with LVEF > 35%.