Diagnostic and Long-Term Prognostic Value of Sensitive Troponin I in Symptomatic Patients Suspected of Acute Heart Failure.

Background: To evaluate the diagnostic and prognostic value of sensitive troponin I (TnI) in patients with acute dyspnea and/or peripheral edema suspected of having acute heart failure (AHF). Methods: This single centre prospective clinical study evaluates 372 patients presenting with acute dyspnea and/or peripheral edema to the emergency department (ED). Measurements of TnI and NT-proBNP were performed at the initial presentation in the ED. All patients were followed up to 5 years. The diagnostic value of TnI compared to NT-proBNP for AHF diagnosis as well as long-term prognostic values for all cause mortality and AHF related rehospitalization were evaluated. Results: TnI plus NT-proBNP improved the diagnosis of AHF (improvement of accuracy (75%, 95% CI 71% - 79%), specificity (68%, 95% CI 62% - 74%), PPV (54%, 95% CI 47% - 62%), and NRI +0.15) compared to NT-proBNP alone (p = 0.0001). TnI levels showed independent prognostic value for all-cause mortality and AHF related rehospitalization after 1 and 5 years (range of AUCs 0.64 - 0.72; p = 0.03 or lower). Highest TnI levels of the 4th quartile revealed an up to 5.5 times higher risk of death within 1 and 5 years (range of HRs: 2.5 - 5.5; p = 0.0001). TnI added significantly to multivariable Cox prediction models even after adjusting for NT-proBNP, particularly in AHF patients (range of HRs: 2.1 -2.7; p <= 0.05). Conclusions: TnI improves AHF diagnosis when combined with NT-proBNP. TnI identifies patients with high 1- and 5-year all-cause mortality and AHF-related rehospitalization risk and adds prognostic value to NT-proBNP.