Post-procedural elevated cardiac troponin I and the association with 5-year mortality in patients undergoing elective PCI

Background The clinically meaningful cardiac troponin I (cTnI) threshold associated with the long-term prognosis in patients undergoing elective percutaneous coronary intervention (PCI) is still debated. Objective To assess the association between different thresholds for post-procedural cTnI and 5-year mortality. Methods The study included 4059 consecutive patients with normal baseline cTnI values who underwent elective PCI. The post-procedural cTnI level was measured at 8–48 h after PCI. The main study endpoints were 5-year all-cause mortality and cardiovascular mortality. Results A cTnI ≥5 times the upper reference limit (URL) as defined by the fourth universal definition of myocardial infarction (4th UDMI), ≥35 times as defined by the Academic Research Consortium-2 criteria, and ≥70 times as defined by the Society for Cardiovascular Angiography and Interventions (SCAI [2014]) was identified in 33%, 6.6%, and 3.3% of patients, respectively. During 5 years of follow-up, the all-cause mortality rate was 3.4% (n = 132) and the cardiovascular mortality rate was 2.0% (n = 77). Both all-cause mortality and cardiovascular mortality increased with higher peak cTnI, and were independently predicted by a cTnI ≥70 times the URL (adjusted hazard ratio [HR] 2.45, 95% confidence interval [CI] 1.20–5.02 and adjusted HR 3.17, 95% CI 1.31–7.67, respectively; reference, cTnI <1 × URL]. The SCAI (2014) threshold was significantly associated with 5-year cardiovascular mortality (adjusted HR 2.66, 95% CI 1.20–5.89; reference, cTnI, <70 × URL) and all-cause mortality (adjusted HR 2.23, 95% CI 1.16–4.30; reference, cTnI <70 × URL). Conclusion In patients with normal pre-procedural cTnI who underwent elective PCI, a post-procedural cTnI ≥70 times the URL independently predicted 5-year all-cause and cardiovascular mortality. Therefore, only the SCAI (2014) post-procedural cTnI threshold was independently associated with long-term mortality.