Critical appraisal of cardiology guidelines on revascularisation: clinical practice

Evidence-based medicine (EBM) provides clinicians with beneficial information. Nonetheless, study findings are often arbitrary, speculative or provisional. The current state of misleading evidence exists in all applications, including those for guideline recommendations. We conductedan appraisal of the American College of Cardiologyand European Society of Cardiology Guidelines for revascularisation of complex coronary anatomy to determine the veracity of the evidence that recommendations were based on. Study-specific critical appraisals were conducted by the authors on the 5-year Synergy between percutaneous coronary intervention with Taxus and cardiac surgery (SYNTAX) and future revascularisation evaluation in patients with diabetes mellitus: optimal management of multivessel disease (FREEDOM) Trials. Each appraisal was performed according the standard EBM practices. A thorough design and analytic critique was performed for each study and the results presented and explained. The guideline recommendations were reviewed in terms of the veracity of the evidence cited. The relative difference in major adverse cardiac and cerebrovascular event (MAACE) rates between coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) are not the 30% level reported by the SYNTAX Trial but closer to 11% difference when study limitations are factored in. Similarly, the 30% effect size in MAACE rates between procedures from the FREEDOM Trial is closer to a non-significant 5% relative difference when limitations are adjusted for. Based on the actual findings of each study, outcomes from procedures by CABG or PCI for multivessel revascularisation are similar and contradict the conclusions of the study authors as well as the recommendations. These recommendations fail to inform current clinical practice.