Prognostic implications of the difference between left ventricular ejection fractions after stress and at rest in addition to the quantification of myocardial perfusion abnormalities obtained with gated SPECT.
BACKGROUND
The prognostic significance of the difference between poststress and at rest left ventricular ejection fraction (ΔLVEF) in patients sent for diagnostic myocardial perfusion study (MPS) is not well characterized. The purpose of this study was to prospectively evaluate the ability of ΔLVEF in further risk stratifying these patients in addition to the severity/extent of myocardial perfusion abnormalities expressed as the total perfusion deficit at stress (sTPD), according to the type of stress used.


RESULTS
Two-day 99mTc-MIBI MPS after stress and rest were obtained for 507 patients subdivided according to the type of stress used, sTPD values, and ΔLVEF. Subsequent cardiac events were determined through a standardized questionnaire applied 1, 2, and 6 years after MPS. Independent of the type of stress used, the 6-year event rate with progressive perfusion and functional abnormalities combined was significant for total events, all-cause death, cardiac death, and revascularization but not for myocardial infarct. When ΔLVEF decreased by more than -10%, only those individuals with sTPD of 5% or less had increased 6-year total event rates [5.9% vs 15% for those submitted to treadmill test (P < 0.001) and 8.3% vs 19% when submitted to pharmacological stress (P = 0.001)]. An sTPD greater than 5% was the only variable predictive of total events when multivariate analysis was applied (P < 0.001 for treadmill exercise and P = 0.033 for dipyridamole).


CONCLUSIONS
Estimation of ΔLVEF in addition to sTPD seems to improve risk stratification for future events when ΔLVEF decreases by more than -10% for those individuals with normal or near-normal myocardial perfusion (sTPD ≤ 5%). An sTPD greater than 5% was a better prognostic indicator of future events when compared with ΔLVEF for individuals with greater perfusion abnormality at stress.
Cardionuclear, Division of Nuclear Medicine, Instituto de Cardiologia, Fundacao Universitaria de Cardiologia, Porto Alegre, Brazil. pdac@terra.com.br
Paulo A
PA
Carvalho
Paula M
PM
Aguiar
Gabriel B
GB
Grossman
Janaina F
JF
Moraes
Ilo S
IS
Baptista
Vania N
VN
Hirakata
Roberto T F
RT
Ludwig
Eduardo B
EB
Ludwig
D003710:Demography; D004176:Dipyridamole / Q000008:administration & dosage / Q000494:pharmacology; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011379:Prognosis; D012146:Rest / Q000502:physiology*; D013318:Stroke Volume / Q000502:physiology*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D004176:Dipyridamole