The role of cardiac troponin I in risk stratification of elderly patients with unstable angina pectoris

Objective To evaluate the role of serum troponin I(cTnI) in risk stratification of elderly patients with unstable angina pectoris (UAP). Methods Serum cTnI levels were measured in 11 healthy subjects(control group), 17 stable angina pectoris(SAP) and 68 UAP elderly patients,respectively. Cardiac events(nonfatal myocardial infarction,cardiac sudden death )were observed within 1 month of hospitalization.Serum cTnI≥1 5 μg/L was considered as the cutoff level for myocardial damage. Results Serum cTnI levels in the UAP group were higher than those in the SAP and control group〔(1 94±0 63), (0 61±0 11) and (0 47±0 08) μg/L, respectively〕(P0 01). In the UAP group, serum cTnI levels increased with increase of Braunwald classification class 〔(1 35±0 28), (2 04±0 31) and (3 17±0 74), respectively〕(P0 05). In Braunwald class Ⅲ patients,the rate of cardiac events in patients with serum cTnI≥1 5 μg/L was much higher than that in those with cTnI1 5 μg/L (42 1% vs 13 3%, P0 05),risk ratio 3 15(95% confidence limit 1 01～9 81).The positive predictive value of serum cTnI≥1 5 μg/L for cardiac events was 42 1% and the negative predictive value was 86 7%. Conclusions Detection of serum cTnI is of clinical value in risk stratification of elderly patients with UAP.