Ejection fraction assessment and survival: an analysis of the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT).
BACKGROUND
Ejection fraction (EF) is an important method of mortality prediction among cardiac patients, and has been used to identify the highest risk patients for enrollment in the defibrillator primary prevention trials. Evidence suggests that measures of EF by different imaging modalities may not be equivalent. In the SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial), the type of imaging modality for EF assessment was not mandated.


METHODS
Baseline assessment of EF was performed using either echocardiography, radionuclide angiography (RNA), or contrast angiography. Multivariable analysis using a Cox proportional hazards model was used to examine whether the modality of assessing EF affected the likelihood of survival.


RESULTS
Among the 2,521 patients enrolled in SCD-HeFT, EF was measured by RNA in 616 (24%), echocardiography in 1,469 (58%), and contrast angiography in 436 (17%). Mean EF as measured by RNA was 25.1% +/- 6.9%; by echocardiography, 23.8 +/- 6.9%; and by angiography, 21.9 +/- 6.9%. These measures were significantly different (P < .001), and each pairwise comparison differed significantly (P < .001 for each). Multivariable analysis showed no significant difference in survival between patients enrolled based on RNA versus echocardiography (HR 1.06, 95% CI 0.88-1.28), RNA versus angiography (HR 1.25, 95% CI 0.97-1.62), or echocardiography versus angiography (HR 1.18, 95% CI 0.94-1.48).


CONCLUSIONS
Among patients enrolled in SCD-HeFT, the distribution of ejection fractions measured by radionuclide angiography differed from those measured by echocardiography or contrast angiograms. Survival did not differ according to modality of EF assessment.
Gula
Lorne J
LJ
University of Western Ontario, London, Ontario, Canada. lgula@uwo.ca
Klein
George J
GJ
Hellkamp
Anne S
AS
Massel
David
D
Krahn
Andrew D
AD
Skanes
Allan C
AC
Yee
Raymond
R
Anderson
Jill
J
Johnson
George W
GW
Poole
Jeanne E
JE
Mark
Daniel B
DB
Lee
Kerry L
KL
Bardy
Gust H
GH
D000368:Aged; D000638:Amiodarone / Q000627:therapeutic use; D000792:Angiography / Q000706:statistics & numerical data; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D017147:Defibrillators, Implantable; D004311:Double-Blind Method; D004452:Echocardiography / Q000706:statistics & numerical data; D005260:Female; D006333:Heart Failure / Q000401:mortality* / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011875:Radionuclide Angiography / Q000706:statistics & numerical data; D018570:Risk Assessment / Q000706:statistics & numerical data; D013318:Stroke Volume / Q000502:physiology*; D016019:Survival Analysis
D000889:Anti-Arrhythmia Agents; D000638:Amiodarone