However, the committee noted that the sensitivity analysis performed by the study authors suggested that the high rate of cross-over might have underestimated the beneficial effect of CABG on mortality, and also noted that the confidence intervals around the absolute effect were reasonably narrow and showed a clinically important benefit. The outcome of all-cause mortality at 30 days was graded moderate quality due to risk of bias (the cross-over rate being higher than the event rate). The evidence for the various quality of life measures were of moderate quality due to risk of bias (attrition). For all-cause hospitalisations, the evidence was graded moderate quality due to imprecision based on the wide confidence intervals around the relative risk estimate, but the committee noted that the confidence intervals around the absolute effect were reasonably narrow and showed a clinically important benefit. The evidence for subsequent CABG procedures was of moderate quality due to risk of bias (attrition), and for both subsequent PCI procedures and stroke was of low quality due to risk of bias (attrition) and imprecision. Finally, the evidence for improvement in NYHA class was graded as low quality due to imprecision and indirectness (the study only reported numbers in class I NYHA at the end of the trial rather than all of those whose NYHA class improved). Invasive strategy versus medical therapy: The evidence for all outcomes was of very low quality. For mortality over the duration of the study, the evidence had very serious imprecision and high risk of bias (unbalanced baseline characteristics between the groups). The quality of life evidence was downgraded for imprecision and risk of bias (lack of blinding). The committee noted that the trial upon which this evidence Chronic Heart Failure Treating Heart Failure NICE 2018. All rights reserved. Subject to Notice of rights. 