Predictive Value of the InterTAK Diagnostic Score differentiating between STEMI versus TCM in a Local Population

Background
The clinical features of Takotsubo cardiomyopathy (TCM) upon presentation often resemble ST-Elevation Myocardial Infarction (STEMI). Although current guidelines advocate using diagnostic coronary angiography as the first-line diagnosis, recent literature has identified clinical parameters to differentiate the two modalities. The InterTAK Diagnostic Score (TDS) was developed to assess the probability of a patient having TCM versus an acute coronary syndrome in the acute stage; however, only 53.9% of the patients in the InterTAK Registry were STEMI patients. The primary objective of this study was to confirm the predictive value of the TDS to differentiate TCM patients from STEMI patients in our local population.

Methods
Patients were included if data was available for the 7 parameters (gender, emotional trigger, physical trigger, psychological disorder, neurological disorder, QTc prolongation, and absence of ST-segment depression) used in the TDS. A retrospective comparison study was conducted on 75 TCM patients and 71 STEMI patients admitted to the hospital between November 2005 and September 2016 for emergency coronary angiography. TCM patients met Mayo Clinic criteria and STEMI patients met STEMI EKG criteria. Groups were compared using logistic regression to control for potential confounders.

Results
Females comprised 91% of TCM patients compared to 38% of STEMI patients. The average age was 66±12 years in both groups. TCM patients were more than 3 times as likely to be positive for each of the 7 parameters. The average TDS was 50.2±13.7 compared to 14.7±15.8 in the STEMI group. Logistic regression showed for each 1 point increase in the TDS, a patient was 1.15 times as likely to have a TCM diagnosis. The area under the curve (AUC) was 0.9465 (sensitivity was 55% and specificity was 97%; OR=1.15 (95% CI: (1.1, 1.21); p<.0001)) with a cut-off of 50 on the TDS. A patient was more than 50 times as likely to have a TCM diagnosis (sensitivity was 76% and specificity was 94%; OR=53.0 (95% CI: (17.0, 165.8), p<.0001)) with a cut-off of 40 on the TDS.

Conclusions
Our results confirm the predictive value of the TDS in a local population of STEMI patients.