Cardiac troponin I levels and alveolar-arterial oxygen gradient in patients with community-acquired pneumonia.
BACKGROUND
Patients with community-acquired pneumonia (CAP) appear to have cardiac stress as demonstrated by elevated B-type natriuretic peptide (BNP). We hypothesised that myocardial stress and decrease in oxygenation might also lead to elevations of cardiac troponin I (cTnI) levels in serum.


OBJECTIVE
The aim of this study was to see if cTnI was associated with the alveolar-arterial oxygen gradient (DeltaA-a), a marker of severity in CAP.


METHODS
Retrospective cohort study of 901 CAP patients with no evidence of acute coronary syndrome presenting to a large, tertiary-care, urban teaching hospital over a 3-year period.


RESULTS
A strong linear trend between log(10)cTnI and DeltaA-a was observed (r(2)=0.76) with a statistically significant Spearman correlation coefficient (r(s)=0.75; p<0.0001) between cTnI and DeltaA-a. A cTnI value of 0.5 ng/ml discriminated mild CAP from moderate-severe CAP with an OR=208 (95% CI: 50.5-408; p<0.0001).


CONCLUSIONS
These data suggest that decreased blood O(2) levels as suggested by elevated DeltaA-a may lead to acute myocardial damage and that cTnI may be useful as a biomarker to stratify risk in subjects with CAP.
Moammar
Mahmoud Q
MQ
Division of Pulmonary Medicine, Department of Internal Medicine, St Joseph's Regional Medical Center, Paterson, NJ, United States.
Ali
Muhammad I
MI
Mahmood
Nader A
NA
DeBari
Vincent A
VA
Khan
M Anees
MA
D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism; D010100:Oxygen / Q000097:blood / Q000378:metabolism*; D018410:Pneumonia, Bacterial / Q000097:blood*; D011650:Pulmonary Alveoli / Q000098:blood supply* / Q000378:metabolism; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013312:Stress, Physiological; D019210:Troponin I / Q000097:blood*
D015415:Biomarkers; D019210:Troponin I; D010100:Oxygen