CLINICAL SIGNIFICANCE OF
ELEVATED TROPONIN I IN
GENERAL HOSPITAL PATIENTS AM Wilson*, A Boyle, A MacIsaac, R Whitbourn, VM Jelinek, P Paull Departments of Cardiology and Chemical Pathology, St Vincent's
Hospital, Melbourne Introduction: An
assay for cardiac Troponin I (Tr-I) has been shown to be valuable in assessing
patients with acute chest pain. A normal serum Tr-I level has been associated
with very low in-hospital and 30 day event rates in patients presenting to
emergency departments with acute chest pain. The role of the assay in a general hospital setting, particularly
in patients without chest pain, has not been established. Aim:To assess the
clinical significance of elevated Troponin I levels in general hospital
patients with and without chest pain. Method:106 consecutive
patients (62 male,44 female.Average age 68.2) with elevated Tr-I were reviewed
for the presence and nature of chest pain, ECG abnormality (old and acute),
elevations in Creatine Kinase(CK-MB),serum creatinine and age. In-hospital
combined events (cardiac death, revascularisation and subsequent myocardial
infarction),in-hospital angiography, 30 day combined events and 30 day
angiography rates were reviewed. Admission for cardiac monitoring (either
coronary care, telemetry or intensive care) was assessed. Results: Of patients found to have
an elevated Tr-I level ,only 55 of 106 (51.9%) had chest pain. Patients with
chest pain had higher rates of in-hospital combined events (38.6%vs11.7% p
0.003), 30 day combined events (43.5%vs11.7% p<0.001) and angiography
(56.1%vs 11.7% p<0.001). There was no significant difference in Tr-I level
between patients with and without chest pain, (21.7 mcg/L +/-17.3 vs 22.7 mcg/L
+/-18.5 p NS). In both groups of
patients, the presence of acute ECG changes was correlated with events. Acute
ECG changes were present in 81.8% of patients with chest pain who had events
and 83.3% of patients without chest pain who had events. Overall, 69.6% of
patients with chest pain had acute ECG changes vs 7.8% without chest pain,
(p<0.001). A subgroup of 15 patients who had no clinical evidence of acute
cardiac disease who were found to have elevated Tr-I levels had no events
during follow-up. Conclusion: Event rates in patients
who have elevated Tr-I without chest pain are low and are associated with acute
ECG abnormality. The principal role of this assay in general hospital practice
appears to be in patients with acute chest pain without clear ECG
evidence of acute ischaemia. The added clinical utility in other patient groups
is unclear. There is need for extensive education for clinicians regarding
patient selection and test interpretation.
