Kucher et al used serum pro-brain natriuretic peptide (proBNP) and troponin T concentrations to evaluate patients after acute pulmonary embolism. The authors are from the University Hospital in Bern, Switzerland.
Adverse events tracked:
(1) in-hospital death
(2) cardiopulmonary resuscitation
(3) mechanical ventilation
(4) requirement for pressor therapy
(5) thrombolysis
(6) surgical embolectomy
(7) catheter fragmentation
Parameters:
(1) proBNP as measured on the Elecsys 2010 immunoassay analyzer from Roche (upper limit of normal reference range 334 pg/mL as given on page 1578).
(2) troponin T by the Elecsys Troponin T Stat immunoassay from Roche (normal range < 0.01 ng/mL)
|
ProBNP Level |
Clinical Implications |
|
< 500 pg/mL |
low risk for complications |
|
>= 500 pg/mL |
intermediate to high risk for complications |
where:
• The cutoff point of 500 pg/mL was determined by ROC curve analysis. This corresponds to 1.5 times the upper limit of normal.
|
Tropinin T Level |
Clinical Implications |
|
< 0.01 ng/mL |
low risk |
|
0.01 to 0.099 ng/mL |
intermediate risk |
|
>= 0.1 ng/mL |
high risk for death and serious adverse events |
where:
• Patients with elevated troponin T levels were at increased risk for early death from right ventricular failure.
• The cutoff of 0.1 ng/mL would be 10 times the upper limit of the normal reference range.
Differential diagnosis: Need to exclude myocardial infarction with congestive heart failure.
Performance:
• The negative predictive value for complications with a proBNP < 500 was 97% with a sensitivity of 95%, so the test was useful for excluding complications. The positive predictive value was 45% with a specificity of 57%, or about a 50-50 chance.
• The negative predictive value for a troponin T < 0.01 ng/mL was 91% with a sensitivity of 80%.
• The negative predictive value for a troponin T < 0.1 ng/mL was 89% while the positive predictive value for >= 0.1 ng/mL was 70%.
Limitations:
• The findings need to be confirmed by more extensive testing.
Implementation Note: The following table might be one way to combine both tests to classify risk. This needs to be verified.
|
pro BNP |
Troponin T |
Risk of Adverse Event |
|
< 500 pg/mL |
< 0.1 ng/mL |
low risk |
|
< 500 pg/mL |
>= 0.1 ng/mL |
intermediate risk |
|
>= 500 pg/mL |
< 0.1 ng/mL |
intermediate risk |
|
>= 500 pg/mL |
>= 0.1 ng/mL |
high risk |
Specialty: Pulmonology
Objective: laboratory tests, severity, prognosis, stage
ICD-10: I26,
