PET and Recovery Following Revascularization (PARR 2)

PET and Recovery Following Revascularization: Outcome and Cost-effectiveness of FDG PET in Left Ventricular Dysfunction (PARR 2)

Rationale: Patients with severe ventricular dysfunction and coronary disease have high morbidity and mortality. They may benefit from revascularization, but have significant peri-operative morbidity and mortality. Positron emission tomography (PET) imaging with F-18-fluorodeoxyglucose (FDG) can detect viable myocardium that may recover from revascularization in such patients. It is unclear whether use of FDG PET in this population is improves outcome or is cost-effective. Objectives: The principal aim is to determine whether FDG PET-guided therapy is effective versus standard care. Secondary objectives are to determine whether FDG PET-guided therapy improves LV function, quality of life and is good value for money versus standard care.

Patients with severe ventricular dysfunction and coronary artery disease have high morbidity and mortality but may benefit from revascularization. However, there is also significant peri-operative morbidity and mortality among these patients. This accounts for the variable approach to these patients in different cardiac centres. Clearly this patient group has the most to gain when coronary revascularization is beneficial, but also the most to lose when it is not helpful. There is a need for an approach that can better define patients with severe ventricular dysfunction due to ischemia, who will be more likely to benefit from revascularization. Positron emission tomography (PET) imaging with F-18-Fluorodeoxyglucose (FDG) has been used to evaluate patients with ventricular dysfunction, to detect ischemic but viable myocardium more likely to recover from revascularization. Recently retrospective studies have shown that FDG PET can identify patients at high risk for cardiac events if they do not undergo revascularization. However, these studies did not evaluate whether FDG PET actually directed therapy decisions and because of their study design, could not determine whether FDG PET altered patient outcome. Our recent studies have shown that FDG PET can have important impact on therapy decisions and that patients with ischemic but viable myocardium are at increased risk. However it remains unclear whether an approach which utilizes FDG PET to define ischemic but viable myocardium can have a beneficial effect on patient outcome. It is also important to consider the potential clinical impact of FDG PET balanced against its limited availability. In addition, despite the cost of the technology, preliminary data from our group and others suggest a potential cost savings. Accordingly, a prospective randomized study is needed to evaluate whether FDG PET directed therapy has a beneficial effect on patient outcome and is cost-effective.

coronary artery disease, left ventricular dysfunction, positron emission tomography, viable myocardium, revascularization, cost effectiveness

Patients will be randomized to standard care will under go other types of imaging or work up for revascularization without PET imaging.

time to occurence of the composite clinical endpoint of cardiac death,myocardial infarction, transplantation, or re-hospitalization for unstable angina or heart failure.

occurrence of the composite endpoint; individual components of the composite endpoint; quality of life, costs, and cost-effectiveness of PET-guided therapy versus control.

Inclusion Criteria: Patient is > 18 years of age. Documented ejection fraction of <35% attributable to CAD. Documented CAD Any patient being considered for revascularization, transplant/heart failure work up or where, in the opinion of the attending physician or surgeon, viability imaging would be considered useful in ongoing clinical management decisions. Exclusion Criteria: Other co-morbid conditions making survival unlikely < 6 weeks post myocardial infarction CAD unsuitable for revascularization emergency revascularization is required. severe valvular disease that requires surgery. Geographically inaccessible Lack of informed consent.

Beanlands RS, Nichol G, Huszti E, Humen D, Racine N, Freeman M, Gulenchyn KY, Garrard L, deKemp R, Guo A, Ruddy TD, Benard F, Lamy A, Iwanochko RM; PARR-2 Investigators. F-18-fluorodeoxyglucose positron emission tomography imaging-assisted management of patients with severe left ventricular dysfunction and suspected coronary disease: a randomized, controlled trial (PARR-2). J Am Coll Cardiol. 2007 Nov 13;50(20):2002-12. doi: 10.1016/j.jacc.2007.09.006. Epub 2007 Oct 10.

D'Egidio G, Nichol G, Williams KA, Guo A, Garrard L, deKemp R, Ruddy TD, DaSilva J, Humen D, Gulenchyn KY, Freeman M, Racine N, Benard F, Hendry P, Beanlands RS; PARR-2 Investigators. Increasing benefit from revascularization is associated with increasing amounts of myocardial hibernation: a substudy of the PARR-2 trial. JACC Cardiovasc Imaging. 2009 Sep;2(9):1060-8. doi: 10.1016/j.jcmg.2009.02.017.

Abraham A, Nichol G, Williams KA, Guo A, deKemp RA, Garrard L, Davies RA, Duchesne L, Haddad H, Chow B, DaSilva J, Beanlands RS; PARR 2 Investigators. 18F-FDG PET imaging of myocardial viability in an experienced center with access to 18F-FDG and integration with clinical management teams: the Ottawa-FIVE substudy of the PARR 2 trial. J Nucl Med. 2010 Apr;51(4):567-74. doi: 10.2967/jnumed.109.065938. Epub 2010 Mar 17.

Shukla T, Nichol G, Wells G, deKemp RA, Davies RA, Haddad H, Duchesne L, Freeman M, Gulenchyn K, Racine N, Humen D, Benard F, Ruddy TD, Chow BJ, DaSilva J, Garrard L, Guo A, Chen L, Beanlands RS. Does FDG PET-assisted management of patients with left ventricular dysfunction improve quality of life? A substudy of the PARR-2 trial. Can J Cardiol. 2012 Jan-Feb;28(1):54-61. doi: 10.1016/j.cjca.2011.09.012. Epub 2011 Dec 3.

Mc Ardle B, Shukla T, Nichol G, deKemp RA, Bernick J, Guo A, Lim SP, Davies RA, Haddad H, Duchesne L, Hendry P, Masters R, Ross H, Freeman M, Gulenchyn K, Racine N, Humen D, Benard F, Ruddy TD, Chow BJ, Mielniczuk L, DaSilva JN, Garrard L, Wells GA, Beanlands RS; PARR-2 Investigators. Long-Term Follow-Up of Outcomes With F-18-Fluorodeoxyglucose Positron Emission Tomography Imaging-Assisted Management of Patients With Severe Left Ventricular Dysfunction Secondary to Coronary Disease. Circ Cardiovasc Imaging. 2016 Sep;9(9):e004331. doi: 10.1161/CIRCIMAGING.115.004331.