IJCS | Volume 32, Nº1, January/ February 2019

74 Figure 3 - “Risk-adjusted, event-free survival curves for time-to-composite event for patients who adhered to PET imaging recommendations (FDG PET Adhere) versus standard care (STD) in patients randomized at sites participating in long-term follow-up. Hazard ratio = 0.73 (95% CI 0.54–0.99; p = 0.042). No at risk = number of patients who had not died, not had transplant, not dropped out, and not had events. Seven patients whose last follow-up date was within 10 days of 1,825 days (5 years) were included in the 5-year total. CI indicates confidence interval; FDG PET, F-18-fluorodeoxyglucose positron emission tomography; and STD, standard care”. – With permission from Mc Ardle et al, Circ Cardiovasc Imaging. 11 Erthal et al. Myocardial viability: from PARR-2 to IMAGE HF - current evidence and future directions Int J Cardiovasc Sci. 2019;32(1)70-83 Review Article management adhered to the imaging recommendations may have an impact on patient outcome. 6 A PARR-2 substudy has supported the importance of adherence to PET findings and that of teamwork of: i) revascularization (surgeons, interventional cardiology); ii) HF; and iii) imaging specialists. 8 This along with iv) access to FDG and v) the cardiac PET imaging experience of a centre has the potential to impact outcome. The Ottawa-FIVE (i.e. i-v above) study has had 111 patients from an experienced center in which PET was easily available and physicians were comfortable with the technology and its interpretation. In this scenario, patients in the FDG PET arm had clear benefit when compared to standard care (19% of cumulative proportion of events in the PET arm versus 41% in the standard care group) andmultivariable analysis showed benefit (HR 0.34; 95% confidence interval 0.16-0.72; p = 0.005). 8 In long-term (5 years) follow-up, the PARR-2 population in which PET recommendations were followed had improved primary outcome (HR 0.73, 95% confidence interval 0.54-0.99, p = 0.042) (Figure 3). 11 In addition, PARR-2 has shown that the amount of hibernating myocardium also plays an important role in patient outcome. 7 With increasing extent of mismatch (hibernatingmyocardium), the likelihood of benefit with revascularization also increases. In this substudy of the PARR-2 trial involving 182 patients in the PET arm, a cutoff of 7% was able to distinguish between patients who would or would not benefit from revascularization, which is in accordance with previous values reported by Di Carli el at. 10 (5%), Lee et al. 12 (7.6%) and Ling et al. 36 (10%) (Figure 4). The STICH trial has observed conflicting results compared to previous studies regarding the benefit of revascularization for patients with viable myocardium. 35 A total of 1,212 patients were randomized to receive optimal medical therapy alone or medical therapy plus revascularization. 35,37 Of these, 601 patients underwent viability assessment independently of the randomization. The primary outcome was defined as all-cause mortality and there was no significant difference in the endpoint between the groups after