Elevation of cardiac troponin I during non-exertional heat-related illnesses in the context of a heatwave.
BACKGROUND
The prognostic value of cardiac troponin I (cTnI) in patients having a heat-related illness during a heat wave has been poorly documented.


METHODS
In a post hoc analysis, we evaluated 514 patients admitted to emergency departments during the August 2003 heat wave in Paris, having a core temperature >38.5 degrees C and who had analysis of cTnI levels. cTnI was considered as normal, moderately elevated (abnormality threshold to 1.5 ngxmL-1), or severely elevated (>1.5 ngxmL-1). Patients were classified according to our previously described risk score (high, intermediate, and low-risk of death).


RESULTS
Mean age was 84 +/- 12 years, mean body temperature 40.3 +/- 1.2 degrees C. cTnI was moderately elevated in 165 (32%) and severely elevated in 97 (19%) patients. One-year survival was significantly decreased in patients with moderate or severe increase in cTnI (24 and 46% vs 58%, all P < 0.05). Using logistic regression, four independent variables were associated with an elevated cTnI: previous coronary artery disease, Glasgow coma scale <12, serum creatinine >120 micromolxL-1, and heart rate >110 bpm. Using Cox regression, only severely elevated cTnI was an independent prognostic factor (hazard ratio 1.93, 95% confidence interval 1.35 to 2.77) when risk score was taken into account. One-year survival was decreased in patients with elevated cTnI only in high risk patients (17 vs 31%, P = 0.04).


CONCLUSIONS
cTnI is frequently elevated in patients with non-exertional heat-related illnesses during a heat wave and is an independent risk factor only in high risk patients where severe increase (>1.5 ngxmL-1) indicates severe myocardial damage.
Hausfater
Pierre
P
Emergency Department Hôpital Pitié-Salpêtrière et Université Pierre et Marie Curie-Paris 6, 47-83 Boulevard de l'Hôpital, 75651 Paris Cedex 13, France. pierre.hausfater@psl.aphp.fr
Doumenc
Benoît
B
Chopin
Sébastien
S
Le Manach
Yannick
Y
Santin
Aline
A
Dautheville
Sandrine
S
Patzak
Anabela
A
Hericord
Philippe
P
Mégarbane
Bruno
B
Andronikof
Marc
M
Terbaoui
Nabila
N
Riou
Bruno
B
D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis; D015331:Cohort Studies; D055874:Extreme Heat / Q000009:adverse effects*; D005260:Female; D018883:Heat Stroke / Q000378:metabolism; D006784:Hospitals, Teaching; D006801:Humans; D008297:Male; D009206:Myocardium / Q000378:metabolism; D010297:Paris; D011237:Predictive Value of Tests; D018570:Risk Assessment; D016019:Survival Analysis; D019210:Troponin I / Q000097:blood*
D015415:Biomarkers; D019210:Troponin I