Clinically Acquired High Sensitivity Cardiac Troponin T is a Poor Predictor of Reduced Left Ventricular Ejection Fraction After ST Elevation Myocardial Infarction: A National Cohort Study-ANZACS-QI 65.

OBJECTIVE: Cardiac troponins (cTn) have been used historically to estimate infarct size in ST elevation myocardial infarction (STEMI). Within a resource constrained health care environment, cTn could therefore be used for prioritisation of patients for cardiac imaging, in particular echocardiography. We aimed to determine how useful routinely collected cTn would be in predicting significant left ventricular (LV) impairment. METHODS: All patients in the All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) registry with their first episode of STEMI between January 2013 and November 2018, who had high sensitivity troponin T measured, were included. We excluded patients with no left ventricular ejection fraction (LVEF) assessment, known LV dysfunction, or prior myocardial infarction. RESULTS: In total, 3,698 patients were included in the analysis. A higher mean hsTnT (admission and peak) was seen in patients with more severely impaired LV function but there was significant overlap in the range of hsTnT between the different LVEF categories. Cardiac troponins demonstrated poor discriminative ability to either predict or exclude significant LV impairment (LVEF <40%). At an optimal cutpoint of 3,405 ng/L, peak hsTnT had a sensitivity of 56.5% (95% confidence interval [CI] 42-62%), a specificity of 65.3% (95% CI 62-79%) and an area under the receiver operating curve of 0.62 (95% CI 0.60-0.64). CONCLUSION: This is the largest study comparing clinically measured troponin levels and LV function in patients presenting with STEMI. A definite, but weak, association was seen between peak troponin and the degree of LV dysfunction, with significant overlap in troponin levels between levels of myocardial dysfunction. Routinely acquired troponin is not suitable for clinical use as a method of prioritising patients for cardiac imaging.

Type of Stressor and Medium-Term Outcomes After Takotsubo Syndrome: What Becomes of the Broken Hearted? (ANZACS-QI 59).

BACKGROUND: Takotsubo syndrome (TS) is often triggered by an acute physical or emotional stressor. We hypothesised that medium-term prognosis may be better for TS patients with an associated emotional stressor than for those with an acute physical illness. METHODS: We identified consecutive TS patients presenting in New Zealand (2006-2018). The clinical presentation and outcomes of TS patients according to types of stressor (physical, emotional or no stressor) were assessed. Post-discharge survival after TS was compared with age- and gender-matched patients after myocardial infarction (MI) and people in the community without known cardiovascular disease (CVD). RESULTS: Of 632 TS patients (95.9% women, mean age 65.0±11.1 years), 27.4% had an associated acute physical stressor, 46.4% an emotional stressor and 26.2% no evident stressor. In-hospital mortality was similar for each group (1.7%, 1.2%, 0.3% respectively, p=0.29). In a median 4.4 years post-discharge there were 54 deaths (53 non-cardiac). Compared with patients without known CVD, TS patients with physical stress and those with MI were less likely to survive (HR 4.46, 95%CI 3.10-6.42; HR 4.23, 95%CI 3.81-4.70 respectively) but survival for TS patients associated with emotional stress or no stressor was similar (HR 1.11, 95%CI 0.66-1.85; HR 1.08, 95%CI 0.54-2.18, respectively). Recurrence was similar among the three groups (p=0.14). CONCLUSION: Takotsubo syndrome associated with physical stressor has a post-discharge mortality risk as high as after MI. In contrast, prognosis for TS triggered by an emotional stressor is excellent, and similar to that of those without known CVD.