1Universitäts-Herzzentrum Freiburg / Bad Krozingen Klinik für Kardiologie und Angiologie Bad Krozingen, Deutschland; 2Universitäts-Herzzentrum Freiburg - Bad Krozingen Innere Medizin III, Kardiologie und Angiologie Freiburg im Breisgau, Deutschland; 3Universitäts-Herzzentrum Freiburg / Bad Krozingen Klinik für Kardiologie und Angiologie II Bad Krozingen, Deutschland
Background: Microvascular obstruction (MVO) at cardiac magnetic resonance (CMR) is a well described risk factor for cardiac events after myocardial infarction (MI).
So far, data about predictors influencing the occurrence of MVO after MI are scarce. As rates of MVO are reported to be only around 40-50% after ST-segment elevation MIs and CMR is a cost- and time intensive procedure, this study aimed to evaluate the prediction of MVO based on high-sensitivity cardiac troponin T (hs-cTnT) levels.
Methods: We evaluated 580 patients with CMR 3 days [interquartile range 2-4 days] after myocardial infarction (399 with ST-segment elevation myocardial infarction, 181 with non-ST-segment elevation myocardial infarction). Hs-cTnT levels were measured at admission as well as 8, 16 and 24 hours after percutaneous coronary intervention (PCI)..
Results: Microvascular obstruction was present in 170 patients (29,3%) at CMR. Maximum hs-cTnT levels were significantly different between patients with and without MVO (maximum hs-cTnT MVO positive vs. MVO negative: 6.89 ± 5.51 vs 2.61 ± 2.71, p<0.000001). Receiver operating characteristic curve showed an area under the curve of 0.8. A cut-off value of >1500 ng/l was a predictor for MVO with a sensitivity of 92.9% and a specificity of 43.4%.
Conclusions: Maximum hs-cTnT levels are a strong predictor for the occurrence of microvascular obstruction at CMR after myocardial infarction as a risk factor for myocardial events. We propose the new cut-off value of a maximum hs-cTnT level of >1500 ng/l within 24 hours after PCI with good sensitivity and acceptable specificity in order to identify patients at high risk of developing MVO. This could be used as a screening tool for post-myocardial infarction patients, who may benefit from further evaluation using cardiac magnetic resonance imaging.