The purpose of this study is to assess the effect of heart muscle viability on left
ventricular (LV) remodeling after a heart attack; to explore the relationships between
retained viability of the area of tissue death (infarct zone), LV remodeling, response to
the Occluded Artery Trial (OAT) intervention, and response to late percutaneous coronary
intervention of the infarct related artery (IRA).
Coronary heart disease is a major health problem in the United States. It is estimated that
in 2003, more than 600,000 Americans had a new heart attack, and more than 400,000
experienced a recurrent heart attack. Up to 40% of individuals with a new or recurrent heart
attack will show a complete occlusion, or blocking, of the IRA on follow-up angiography.
Many people with an occluded IRA post-heart attack are at risk for progressive LV remodeling
in the heart, which can lead to congestive heart failure.
The NHLBI-funded OAT study is testing the hypothesis that opening an occluded IRA 3 to 28
days following a heart attack will reduce the composite endpoint of mortality, recurrent
heart attack, and New York Heart Association class IV heart failure over a three-year
follow-up period. OAT has enrolled approximately 1,100 participants at 240 centers in 24
countries. Among the mechanisms proposed to explain the benefit of late revascularization,
recovery of LV function and attenuation of LV remodeling due to restoration of blood flow to
viable myocardium, or heart muscle, is the most plausible.
An estimated 200 individuals who have had a heart attack will be enrolled in this study. The
primary aims of this study are the following: 1) to test the hypothesis that participants
who demonstrate preservation of viability within the infarct zone will have less progressive
remodeling compared to participants exhibiting predominant infarct, and 2) to test the
hypothesis that preservation of viability will modify the treatment effect of randomization
to late revascularization in participants with an occluded IRA 3 to 28 days after the heart
attack. All participants will have resting gated Tc-99m sestamibi SPECT imaging at baseline,
and again 1 year later. Parameters of baseline viability within the infarct zone, and serial
measures of LV volume change and function will be centrally assessed by the Cardiac Imaging
Core Laboratory at Tufts Medical Center. The major study endpoint to address the hypotheses
will be serial change in LV end-diastolic volume, based on the degree of preservation of
viability within the defined infarct zone. Sample size calculations will be based on data
evaluated by the same group from a similar number of participants studied at a similar
number of clinical sites.
- Has experienced a heart attack 3 to 28 days prior to study entry
- Has an occluded IRA at catheterization