Increasing benefit from revascularization is associated with increasing amounts of myocardial hibernation: a substudy of the PARR-2 trial.
OBJECTIVE
We sought to determine: 1) whether F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) parameters identify high-risk patients who gain benefit from revascularization; 2) whether there is a cut point for such benefit; and 3) predictors of outcome in patients with severe left ventricular (LV) dysfunction due to coronary artery disease.


BACKGROUND
Patients with ischemic LV dysfunction might benefit from revascularization but not without risk. The FDG PET imaging can detect viable myocardium that recovers after revascularization. In the PARR-2 (PET and Recovery Following Revascularization-2) trial, FDG PET imaging showed a nonsignificant trend for improved outcome compared with standard care. Understanding the predictors of outcome from this prospective trial should help better identify patients at risk and which patients most benefit from revascularization.


METHODS
This post hoc analysis included 182 patients with left ventricular ejection fraction (LVEF) <35% and coronary artery disease, being considered for revascularization work-up, and randomized to the PET arm of PARR-2. The primary outcome was a composite of cardiac death, myocardial infarction, or cardiac repeat hospital stay at 1 year.


RESULTS
There is an interaction between PET mismatch and protocol revascularization such that higher mismatch, when combined with revascularization, yields fewer primary outcome events (p = 0.02). On the basis of adjusted Cox modeling, with reduced mismatch (<7%), the risk is not significantly different with or without revascularization. As mismatch increases above this mark, risk is reduced with revascularization. Increasing creatinine (for a 10-mumol/l increase: hazard ratio: 1.03, 95% confidence interval: 1.01 to 1.06, p = 0.010) is also associated with increased risk, whereas decreasing LVEF (for a 2% decrease: hazard ratio: 1.08, 95% confidence interval: 0.99 to 1.18, p = 0.087) trends toward an association with increased risk.


CONCLUSIONS
In this post hoc analysis, patients with ischemic cardiomyopathy with larger amounts of mismatch have improved outcome with revascularization. Renal function was also an independent predictor of outcome. The FDG PET seems to define high-risk patients that gain benefit from revascularization. (PET and Recovery Following Revascularization [PARR 2]; NCT00385242).
D'Egidio
Gianni
G
National Cardiac PET Centre, Division of Cardiology, Cardiovascular Research Methods Centre, University of Ottawa Heart Institute, Ottawa, Ontario K1Y 4W7, Canada.
Nichol
Graham
G
Williams
Kathryn A
KA
Guo
Ann
A
Garrard
Linda
L
deKemp
Robert
R
Ruddy
Terrence D
TD
DaSilva
Jean
J
Humen
Dennis
D
Gulenchyn
Karen Y
KY
Freeman
Michael
M
Racine
Normand
N
Benard
Francois
F
Hendry
Paul
P
Beanlands
Rob S B
RS
D000368:Aged; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging / Q000401:mortality / Q000628:therapy*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007668:Kidney / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology / Q000401:mortality; D009204:Myocardial Revascularization / Q000009:adverse effects / Q000401:mortality; D017682:Myocardial Stunning / Q000000981:diagnostic imaging / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology*; D010359:Patient Readmission; D018579:Patient Selection; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D018570:Risk Assessment; D012307:Risk Factors; D013318:Stroke Volume; D013997:Time Factors; D014022:Tissue Survival; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18