Impact of low-level cardiomyocyte injury on prognosis in patients with non-obstructive coronary artery disease: a retrospective cohort study

Abstract Background: Mild elevation of serum cardiac troponin (Tn) reflects myocardial injury and is associated with cardiovascular events, even without overt cardiovascular disease. The purpose of this study was to investigate the possible mechanism of mild elevation of high-sensitivity cardiac troponin I (hs-cTnI) and its impact on prognosis in patients with non-obstructive coronary artery disease (CAD).Methods: 474 consecutive patients with suspected CAD and without significant coronary artery stenosis (<50%) who underwent adenosine triphosphate disodium (ATP) stress MCE were followed up (median, 41months) for endpoint events. Hs-cTnI was tested before MCE. Replenishment velocity (β), relative myocardial blood flow (rBV) and myocardial blood flow reserve (MBFR) were measured by stress MCE.Results: A total of 214 (45.1%) patients had hs-cTnI concentrations exceeding the limitation of detection (LOD) (0.001 ng/ml). Compared to patients with hs-cTnI below LOD, patients with higher hs-cTnI were older (p<0.05), had higher prevalence of atrial fibrillation (p<0.001) and lower MBFR (p<0.001). After adjustment, the association was still significant between detectable hs-cTnI and MBFR (odds ratio = 0.200; 95% CI: 0.043,0.923, P = .039). Detectable hs-cTnI was associated with endpoint events independent of MBFR (adjusted hazard ratio 8.927,95%CI 1.341-149.48, P=0.028). Hs-cTnI higher than LOD had greater cumulative event rate (log-rank P=0.004). The risk of incident endpoint events was greater for higher hs-cTnI (≥0.001 versus 更多