N-terminated natriuretic propeptide type B is a better prognostic factor than MB isoenzyme of creatine kinase in patients after cardiac arrest

Background and goals

The aim of our study was to assess concentrations of N-terminated propeptide type B (NTBNP), a marker of cardiac insufficiency, and MB isoenzyme of creatine kinase (CKMB), which level is adequate to the area of acute myocardial necrosis, and to compare their predictive values of survival in patients after cardiac arrest (CA).

Participants

Fifty-two patients after CA (CA-patients) of age 62 ± 13 years. In 34 patients CA appeared during acute coronary syndrome. Twenty-six patients died after CA (CA-D), and 26 patients survived and were discharged from hospital (CA-S).

Methods

The state of patients after CA was assessed by scales of proven values of survival after CA used in critical care: Glasgow Coma Scale (GCS), Multiple Organ Dysfunction Score (MODS), Simplified Acute Physiology Score II (SAPS II) and Acute Physiology and Chronic Health Evaluation II (APACHE II). In CA-patients the concentrations of NTpBNP and CKMB were measured in venous blood samples taken just after CA (day 0) and on two consecutive days (day 1 and day 2) at 8:00 am. In CA-D and CA-S patients the concentrations of NTBNP and CKMB were compared. In regression and survival analysis, predictive values of concentrations of NTBNP and CKMB were assessed. Correlations among concentrations of NTBNP, CKMB and values of the scales used in critical care were estimated by Spearman's correlation coefficient.

Results

The mean concentrations of NTBNP and CKMB were higher in CA-D than in CA-S patients 3 days running but were significantly higher only for NTBNP on day 1 (114,000 ± 112,000 vs 45,100 ± 58,000 pmol/l, P < 0.027). On day 1 similar values of the OR of survival after CA of concentrations of NTBNP (OR 5.7 for concentrations >50,000 or ≤ 50,000 pmol/l, P < 0.02) and concentrations of CKMB (OR 7.5 for concentrations >40 or ≤ 40 U/l, P < 0,02) were found, but it was only concentrations of NTBNP whose OR was significant in blood on day 0 (OR 5.8 for concentrations >50,000 or ≤ 50,000 pmol/l, P < 0.02). The relationship to survival of concentrations of CKMB on day 1 and concentrations of NTBNP on day 0 and day 1 was also confirmed in Kaplan–Meyer survival analysis. Only concentrations of NTBNP revealed good correlation with values of the scales used in critical care.

Conclusion

On day 1 after CA, concentrations of NTBNP and CKMB are of predictive values of survival. In blood taken just after CA, only the concentration of NTBNP reveals a predictive value of survival. NTBNP is a better predictor of survival after CA than CKMB because its concentration is of predictive value in the first 2 days after CA and of good fit with scales concerning the severity of state of patients after CA.