Mechanical Dyssynchrony Defined by Phase Analysis from GSPECT:

All Rights Reserved, Duke Medicine 2008

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

• Standard deviation

• Bandwidth

Dyssynchrony measures

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

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.

39%

71%

31%

56%52%


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)

Stress testing

Angiographically significant coronary disease

GSPECT MPI between July 2003 and August 2009

Exercise treadmill testing was preferred


Emory Toolbox Software (Atlanta, GA) programs were used to assess mechanical dyssynchrony

Dyssynchrony Measurement

Statistical Analysis

Cox proportional hazards modeling

Kaplan-Meier survival analysis

• Unadjusted• Adjusted for standard clinical covariates• Adjusted for above and LV function


Age, median (IQR) 64 (55, 72)

Male sex 69.6

Race

White 73.8

Black 22.2

Other 4.0

Congestive heart failure 24.3

Diabetes mellitus 36.2

Hypertension 76.1

Hyperlipidemia 69.7

COPD 6.6

Renal disease 5.4

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

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


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

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


Outcomes Associated with Bandwidth By LVEF*

Outcome† Left Ventricular Function HR (95% CI) Interaction P

All-cause mortality EF > 35% 1.06 (1.04-1.07) 0.002

EF < 35% 0.97 (0.93-1.02)

Cardiovascular Mortality EF > 35% 1.07 (1.05-1.09) 0.002

EF < 35% 0.99 (0.93-1.05)

*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 byLeft Ventricular Function and Bandwidth

Pro

po

rtio

n d

ead

Years

P=0.604

P<0.001

EF < 35%, BW > 100

EF < 35%, BW < 100

EF > 35%, BW > 100

EF > 35%, BW < 100


Cardiovascular Death Over Time Stratified byLeft Ventricular Function and Bandwidth

Pro

po

rtio

n d

ead

Years

EF < 35%, BW > 100

EF < 35%, BW < 100

EF > 35%, BW > 100

EF > 35%, BW < 100 P=0.783

P<0.001


Implication

Patients with LVEF > 35% who do not meet current criteria for CRT may nonetheless benefit from device placement.

Principal Finding

Mechanical dyssynchrony detected by GSPECT MPI is an early marker of all-cause and cardiovascular mortality among patients with LVEF >35%.


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%.

Documents

Mechanical Dyssynchrony Defined by Phase Analysis from GSPECT: