Impact of the risk-treatment paradox on in-hospital and long-term outcomes in patients with very high-risk non-ST-elevation acute coronary syndrome.

Background and objectives The risk-treatment paradox (RTP) has not been studied in very high-risk patients with non-ST-elevation acute coronary syndrome (NSTE-ACS). We aimed to describe the cohort of very high-risk NSTE-ACS patients, analyse the impact of RTP on outcomes, and identify subgroups of patients who derive the greatest benefit from immediate invasive coronary angiography (ICA). Methods This retrospective analysis included 340 patients diagnosed with NSTE-ACS who met at least one of the established criteria for very high risk at admission. RTP was defined as any management tactic other than emergency (<2 h) ICA. Ongoing myocardial ischaemia (OMI) was defined as a combination of ongoing or recurrent chest pain and/or dyspnoea, along with at least one additional established very high-risk criterion. Results RTP was identified in 213 cases (62.6%). There was no adverse effect of RTP on in-hospital mortality [14% vs. 10% in the RTP group, P = 0.34, odds ratio (OR) 0.708; 95% confidence interval (CI) 0.36-1.37] or on the incidence of long-term major adverse coronary events (MACE). An independent predictor of adverse outcomes was evidence of OMI at hospital admission. Signs of OMI were observed in 168 patients (49.4%). In this subgroup, failure to perform emergency invasive coronary angiography was associated with a higher incidence of MACE during the three-year follow up (29% vs. 47.5% in the RTP group, P=0.02, OR 2.2; 95% CI 1.0-4.5). Interpretations and conclusions There was no significant effect of risk-treatment paradox on outcomes in very high-risk patients. Patients with signs of ongoing myocardial ischaemia benefit most from undergoing emergency invasive coronary angiography with the intention of performing percutaneous coronary intervention within two hours.