Risk-stratification of patients diagnosed with acute pulmonary embolism is generally considered a valuable enterprise. High-risk patients are reasonable to observe as an inpatient for deterioration leading to thrombolysis or other invasive procedures, while low-risk patients can be obviated the costs and risks of an inpatient stay. The Pulmonary Embolism Severity Index is in use in many settings to make such a determination – calibrated for maximum sensitivity to detect adverse events.
Cardiac troponin has been similarly used for risk-stratification – but mainly for determining “high-risk” and the spectrum of submassive PE, as many patients with negative conventional troponins still progress to poor outcomes. This study evaluates the utility of the highly-sensitive troponin – threshold of detection 0.012 ng/mL – for risk-stratification.
Based on retrospective review of 298 consecutive patients with acute PE, these authors found about half had a detectable hsTnI, while the remainder were below the limit of detection. With regards to “hard events” as a primary outcome – death, CPR, or thrombolysis – no patient with an undetectable troponin had such an event in the hospital. Conversely, 15 (9%) patients with a detectable hsTnI suffered a serious outcome. Interestingly, based on a rough evaluation of the Kaplan-Meier survival curves, even patients stratified as intermediate, high, or very high risk by PESI were still event-free if their hsTnI were negative – while a small number of patients low-risk by PESI had events, but only with positive hsTnI.
This is not the most robust evaluation of such risk-stratification, and there’s clearly some oddities in the chart review, given an odd spate of low-risk patients deteriorating between days 10 and 20. However, it may be the case the hsTnI does as-good or better at risk-stratifying than our current tools – and may be considered for inclusion into future ones.
“The Prognostic Value of Undetectable Highly Sensitive Cardiac Troponin I in Patients With Acute Pulmonary Embolism”
http://www.ncbi.nlm.nih.gov/pubmed/25079900