SIX MONTH FOLLOW-UP OF PATIENTS WHO HAVE HAD CARDIAC
TROPONIN I (cTnI) ELEVATIONS DURING ROUTINE PERCUTANEOUS CORONARY INTERVENTION
(PCI). C.H.
Ang*, S.F. Castle, RAP Skyme-Jones, N. Balazs, I.T. Meredith. Centre
for Heart and Chest Research, Monash University and Biochemistry Department,
Monash Medical Centre, Melbourne. Serum cardiac troponins are markers with
enhanced specificity and sensitivity able to detect minimal myocardial injury
(MMI)following PCI. Little is known
about the frequency of MMI following PCI and its influence on long term
outcome. Pre and post routine angioplasty levels of serum cTnI, creatine kinase
(CK), creatine kinase MB (CKMB) were prospectively measured in 267 patients,
over a 8-month period. 15 patients with acute myocardial infarction were
excluded. cTnI was classified as normal (<0.4 mcg/L, Group I); MMI
(≥0.4-1.49 mcg/L, group II), and acute myocardial infarction (≥1.5
mcg/L, group III). 4.3% of patients had CKMB elevation ≥ twice upper
limit of normal (2xULN ) and 2% had total CK≥2xULN. 51 patients (20%) had
elevated cTnI ≥0.4 mcg/L post PTCA with 29 patients (12%) sustaining MMI.
cTnI elevation was independent of age, gender, cardiovascular risk factors,
acute coronary syndrome, vessel type, lesion type, lesion position, number of
balloon inflations, balloon pressures or stent size and the duration of
procedure. In Group II (MMI), there was a significant increase in AMI (3.4% vs 0.5%, p=0.01) and repeat angiogram
(6.9% vs 0.5%, p=0.02)at 30 days.
Patients with cTnI≥0.4 mcg/L (Groups II & III) had a greater
incidence of AMI (2% vs 0%, p=0.05)
and coronary bypass surgery (CABG)(2% vs
0%, p=0.05) at 30 days. The incidence of recurrent angina, repeat angiogram or
PCI, CABG, stroke and death were, however,
similar at 3 and 6 months. A raised cTnl level after PCI is associated
with an increased risk of AMI and need for CABG at 30 days but does not alter 6
month outcome.
