Background and Purpose: Acute Ischemic Stroke (AIS) patients may have high sensitivity serum troponin (cTn) levels drawn upon admission, although it is unclear how frequently cTn levels are elevated, and whether these levels are associated with cardiac causes of stroke as seen on echocardiogram. We investigated the prevalence and positivity of cTn and echocardiogram testing within a large biracial population that is representative of the US.
Methods: Within a catchment area of 1.3 million we screened local hospital admissions in 2010 using ICD-9 discharge codes 430-436 and ascertained all physician-confirmed AIS cases by standardized retrospective chart review, including diagnostic test results. Any positive cTn was defined by the standard 99th percentile cutoff. Echocardiogram findings of interest were defined as in the table. Logistic regression was used for analyses, controlling for age, sex, race and prior history of cardiac disease.
Results: Of the 1999 AIS cases that presented to an ED in the region 1706 (85.3%) had a cTn drawn and 1590 (79.5%) had an echocardiogram. A positive cTn was seen in 353/1706 (20.7%) and 160/1590 (10%) had an echocardiogram finding of interest. Of the 1377 that had both tests performed, a positive cTn was associated with an abnormal echocardiogram (adjusted OR 2.9 95% CI 2-4.2). A negative cTn did not significantly alter the odds of having an abnormal echocardiogram (Negative Likelihood Ratio=0.66).
Conclusion: Testing with serum cTn and echocardiogram was common within our population. Troponinemia above the 99th percentile was prevalent and was associated with clinically relevant structural cardiac disease on echocardiogram. However absence of troponinemia was not informative regarding the probability of a normal echocardiogram, and therefore does not obviate the need for echocardiography in this at risk population.