Supplementary Material for: α1-antichymotrypsin complex (SERPINA3) is an independent predictor of all-cause but not cardiovascular mortality in patients hospitalized for chest pain of suspected coronary origin.

Introduction: SERPINA3 is an acute phase protein triggered by inflammation. It is upregulated after an acute myocardial infarction (AMI). Data on its long-term prognostic value in MI patients are scarce. We aimed to assess the utility of SERPINA3 as a prognostic marker in patients hospitalized for chest pain of suspected coronary origin. Methods: A total of 871 consecutive patients, 386 diagnosed with AMI, were included. Stepwise Cox regression models, applying continuous loge-transformed values, were fitted for the biomarker with all-cause mortality and cardiac death within 2-years or all-cause mortality within median 7 years as dependent variables. An analysis of MI and stroke, and combined endpoints, respectively, was added. The hazard ratio (HR) (95% CI) was assessed in a univariate and multivariable model. Results: Plasma samples from 847 patients were available. By 2 years follow-up, 138 (15.8%) patients had died, of which 86 were cardiac deaths. The univariate analysis showed a significant association between SERPINA3 and all-cause mortality [HR 1.41 (95% 1.19-1.68), p<0.001], but not for cardiac death. Associations after adjustment were non-significant. By 7 years follow-up, 332 (38.1%) patients had died. SERPINA3 was independently associated with all-cause mortality from the third year onwards. The HR was 1.14 (95% CI, 1.02-1.28), p=0.022. Similar results applied to combined endpoints, but not for MI and stroke, respectively. The prognostic value of SERPINA3 was limited to non-AMI patients. No independent associations were noted among AMI patients. Conclusions: SERPINA3 predicts long-term all-cause mortality, but failed to predict outcome in AMI patients.