Do cardiac troponins provide prognostic insight in hemodialysis patients?
BACKGROUND
The diagnosis of myocardial necrosis in patients with chronic renal failure is often difficult because biochemical markers of cardiac damage such as creatine kinase MB (CKMB) and cardiac troponin T (cTnT) may be spuriously elevated. Recent small studies also report unexplained elevations in cardiac troponin I (cTnI) in chronic renal failure patients undergoing hemodialysis. The relative incidence of elevated cardiac troponins in this population and their relationship to clinical events remain unknown.


OBJECTIVE
To determine the incidence and prognostic significance of asymptomatic elevations of cTnT and cTnI in patients undergoing hemodialysis for chronic renal failure.


METHODS
Prospective cohort study.


METHODS
University tertiary care teaching hospital.


METHODS
One hundred thirteen patients over 21 years of age undergoing onsite hemodialysis were enrolled between December 1997 and February 1998.


METHODS
All-cause and cardiovascular mortality, hospitalization for acute myocardial infarction, unstable angina or congestive heart failure, new onset sustained arrhythmia or need for unscheduled emergency hemodialysis due to volume overload at 30 days and six months.


RESULTS
The incidence of abnormal results for cTnT, cTnI and CKMB were 42%, 15% and 4%, respectively. Independent predictors of mortality at six months were median age greater than 63 years (odds ratio 14.3, 95% CI 1.5 to 130.3, P=0.019) and positive cTnT (odds ratio 13.6, 95% CI 2.5 to 73.2, P=0.002). Diabetics were more likely to have positive cTnI and cTnT results than nondiabetics (P<0.001 and P=0.023, respectively).


CONCLUSIONS
cTnT is commonly elevated in patients with chronic renal failure even in the absence of acute coronary syndromes. cTnT may be an important independent prognostic marker in patients on hemodialysis for chronic renal failure. While less common, elevations of cTnI are more frequent than CKMB elevations. The basis of these cardiac troponin elevations is unclear. These findings may represent, in part, a subclinical myocardial injury, an inflammatory response to chronic renal failure or a chronically volume overloaded state.
Choy
Jonathan B
JB
Division of Cardiology, University of Alberta Hospital, Edmonton, Canada.
Armstrong
Paul W
PW
Ulan
Raymond A
RA
Campbell
Patricia M
PM
Gourishankar
Sita
S
Prosser
Connie I
CI
Tymchak
Wayne J
WJ
D000368:Aged; D000369:Aged, 80 and over; D000416:Alberta / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D018572:Disease-Free Survival; D023381:Endpoint Determination; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000097:blood / Q000401:mortality / Q000628:therapy; D006801:Humans; D015994:Incidence; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000401:mortality / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000097:blood / Q000401:mortality / Q000628:therapy; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D006435:Renal Dialysis; D012709:Serum Albumin / Q000378:metabolism; D016896:Treatment Outcome; D019210:Troponin I / Q000097:blood; D020107:Troponin T / Q000097:blood
D015415:Biomarkers; D012709:Serum Albumin; D019210:Troponin I; D020107:Troponin T