Download Mechanical Dyssynchrony Defined by Phase Analysis from GSPECT

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
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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.
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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.
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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.
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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.
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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
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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
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Baseline Characteristics (n=1,434)*
Age, median (IQR)
Male sex
Race
White
Black
Other
Congestive heart failure
Diabetes mellitus
Hypertension
Hyperlipidemia
COPD
Renal disease
64 (55, 72)
69.6
73.8
22.2
4.0
24.3
36.2
76.1
69.7
6.6
5.4
*Data are presented as % unless otherwise specified.
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Outcomes Associated with Bandwidth*
All-cause Mortality
P
Cardiovascular Mortality
P
Unadjusted
1.06 (1.05, 1.08)
<0.001
1.08 (1.06-1.10)
<0.001
Clinical Model†
1.06 (1.04, 1.07)
<0.001
1.07 (1.05-1.09)
<0.001
Clinical Model + EF‡
1.02 (1.00-1.04)
0.120
1.02 (1.00-1.05)
0.093
*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
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Outcomes Associated with Phase SD*
All-cause Mortality
P
Cardiovascular Mortality
P
Unadjusted
1.21 (1.16, 1.27)
<0.001
1.30 (1.23-1.38)
<0.001
Clinical Model†
1.19 (1.14, 1.25)
<0.001
1.23 (1.16-1.31)
<0.001
Clinical Model + EF‡
1.06 (0.99-1.13)
0.101
1.06 (0.98-1.16)
0.158
*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
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Outcomes Associated with Bandwidth By LVEF*
Outcome†
All-cause mortality
Cardiovascular Mortality
Left Ventricular Function
HR (95% CI)
Interaction P
EF > 35%
1.06 (1.04-1.07)
0.002
EF < 35%
0.97 (0.93-1.02)
EF > 35%
1.07 (1.05-1.09)
EF < 35%
0.99 (0.93-1.05)
0.002
*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.
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All-Cause Death Over Time Stratified by
Left Ventricular Function and Bandwidth
EF < 35%, BW > 100
Proportion dead
EF < 35%, BW < 100
P=0.604
EF > 35%, BW > 100
EF > 35%, BW < 100
P<0.001
Years
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Cardiovascular Death Over Time Stratified by
Left Ventricular Function and Bandwidth
EF < 35%, BW > 100
Proportion dead
EF < 35%, BW < 100
EF > 35%, BW > 100
P=0.783
EF > 35%, BW < 100
P<0.001
Years
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Principal Finding
Mechanical dyssynchrony detected by GSPECT MPI is an
early marker of all-cause and cardiovascular mortality
among patients with LVEF >35%.
Implication
Patients with LVEF > 35% who do not meet current criteria
for CRT may nonetheless benefit from device placement.
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Limitations
Retrospective, observational study design
Sampling bias
Diagnostic bias
Presence of LBBB unknown
Limited number of patients with reduced EF
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Conclusions
Mechanical dyssynchrony detected by phase
analysis of GSPECT MPI can identify patients
with coronary disease at increased risk of allcause 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%.
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