Can Dobutamine Stress Echocardiography Induce Cardiac Troponin Elevation?

Myocardial injury in stress echocardiography: Comparison of dobutamine, dipyridamole and dynamic stressors-single center study

OBJECTIVES

In stress echocardiography (SE), dipyridamole (DIP) and dynamic stress (ExSE) are reported as being safer than dobutamine stress echocardiography (DSE). We investigated whether these commonly used stressors cause myocardial injury, measured by high sensitivity troponin T (hsTnT).

METHODS

One hundred and thirty five patients (DSE n = 46, ExsE n = 46, DIP n = 43) with negative result of SE were studied. The exclusion criteria were known ischaemic heart disease (IHD), baseline wall motion abnormalities, left ventricle systolic dysfunction/regional wall motion abnormalities, septum/posterior wall ≥13 mm, diabetes/pre-diabetes, baseline hsTnT level ≥14 ng/L, baseline blood pressure ≥160/100 mmHg, peak pulmonary pressure ≥45mmHg, eGFR <1ml/s/1.73m² , more than mild to moderate valvular disease and dobutamine side effects. HsTnT was measured before and 180 minutes after the test.

RESULTS

All patients had low pre-test probabilities of having obstructive IHD. HsTnT increased in DSE, less so in ExSE, and was unchanged in the DIP group (∆hsTnT 9.4 [1.5-58.6], 1.1 [-0.9-15.7], -0.1 [-1.4-2.1] ng/L, respectively, p<0.001). In DSE, the ∆hsTnT was associated with peak dobutamine dose (r = 0.30, p = 0.045), test length (r = 0.43, p = 0.003) and atropine use (p<0.001). In ExSE, the hsTnT increase was more likely in females (p = 0.012) and the elderly (>65 years) (r = 0.32, p = 0.03); no association was found between atropine use (p = 0.786) or test length and ∆hsTnT (r = 0.10, p = 0.530).

CONCLUSIONS

DSE is associated with myocardial injury in patients with negative SE, no injury was observed in DIP and only mild case in ExSE. Whether myocardial injury is causative of the higher reported adverse event rates in DSE remains to be determined.

Post-exercise high-sensitivity troponin T levels in patients with suspected unstable angina

Background

Previous studies showed that troponin blood levels may increase after exercise. In this study we assessed whether, among patients admitted with suspected unstable angina, the increase in high-sensitive troponin T (hs-TnT) levels after exercise stress test (EST) might help identify those with obstructive coronary artery disease (CAD) and predict symptom recurrence during short term follow-up.

Methods

Maximal treadmill EST was performed in 69 consecutive patients admitted to the emergency room with a suspicion of unstable angina (acute chest pain but confirmed normal serum levels of cardiac troponins) was measured before and 4 hours after EST. Coronary angiography was performed in 22 patients (32.8%).

Results

hs-TnT increased after EST compared to baseline in the whole population (from 0.84±0.65 to 1.17±0.87 ng/dL, p<0.001). The increase was similar in patients with positive (n = 14) and negative (n = 55) EST (p = 0.72), and was also similar in patients with (n = 12) and without (n = 10) obstructive CAD at angiography (p = 0.91). The achievement of a heart rate at peak EST ≥85% of that predicted for age was the variable mainly associated with the post-EST hs-TnT increase at multivariable linear regression analysis (p = 0.005). The change after EST of hs-TnT did not predict the recurrence of symptoms or readmission for chest pain at 6-month follow-up.

Conclusions

Our data show that hs-TnT increased after EST in patients with suspected unstable angina, which seemed largely independent of most clinical and laboratory variables. Thus, hs-TnT assessed after EST does not seem to be helpful to identify patients with obstructive CAD in this kind of patients.

High sensitivity cardiac troponins: Can they help in diagnosing myocardial ischaemia?

BACKGROUND

Cardiac troponin is the most sensitive marker of myocardial injury, but controversy still exists about its role in detecting ischaemia.

METHODS

To investigate the role of troponin as a marker of stress-induced ischaemia, circulating high sensitivity cardiac troponin T (hs-cTnT) was measured and compared with the MB fraction of creatine kinase (CK-MB) in 125 patients undergoing a stress test (53 electrocardiogram/echo exercise, 42 echo dipyridamole and 30 echo dobutamine tests).

RESULTS

Plasma concentrations of hs-cTnT increased after the tests in 90/125 patients, while an increase of CK-MB was seen in 31/125 patients ( p<0.0001). Overall, hs-cTnT significantly increased from 17.5±16.9 ng/l to 25.5±27.9 ng/l ( p<0.0001), without significant changes of CK-MB. Significant increments in hs-cTnT were documented after exercise test (from 15.9±11.9 ng/l to 19.5±13.6 ng/l, p<0.0001) and dobutamine test (from 20.6±20.8 ng/l to 37.8±31.1 ng/l, p=0.0006), in absence of changes in CK-MB according to each stressor. Among the 125 tests, 84 were diagnosed as negative and 41 as positive for myocardial ischaemia. Significant increments in hs-cTnT were detected after both negative (from 18.6±19.2 ng/l to 27.1±32.1 ng/l, p=0.0018) and positive test (from 15.2±10.8 ng/l to 22.3±16.2 ng/l, p=0.0005), without significant changes of CK-MB according to the test result. Despite a positive correlation between stress-induced increase of hs-cTnT and obstructive coronary artery disease, the release of troponin was observed also in a significant proportion of patients without coronary stenoses. Left ventricular hypertrophy markedly enhanced myocardial release of troponin.

CONCLUSIONS

Circulating troponin increases in most patients undergoing a stress test, irrespective of the test result and of coronary artery disease. Plasma release of troponin depends on multiple pathogenetic mechanisms, making the biomarker a not reliable tool in detecting transient ischaemia.

Effect of dobutamine stress echocardiography on serum heart fatty acid binding protein levels

Objective Heart fatty acid binding protein (HFABP) is a low-molecular-weight free protein that is abundant in the intracytoplasmic space of myocytes. Due to its unique features, serum HFABP levels may increase in myocardial ischaemia. The aim of this study was to evaluate the effect of myocardial ischaemia induced by dobutamine stress echocardiography (DSE) on serum HFABP levels. Methods and results A total of 30 consecutive patients with suspected myocardial ischaemia underwent DSE examination. HFABP levels were measured immediately before and 1 hour after DSE. HFABP rose significantly in individuals in the DSE positive group (1.66 ± 1.18 ng/ml vs 2.65 ± 1.34 ng/ml, P = 0.004), but remained unchanged in the DSE negative group (1.61 ± 0.77 ng/ml vs 1.85 ± 0.76 ng/ml, P = 0.066). Conclusion Serum HFABP levels increased significantly at 1 hour in the presence of ischaemia induced by DSE in patients with stable clinical coronary syndromes. No such increase was evident in the absence of ischaemia.

Update on cardiac imaging techniques 2012

Cardiac imaging is one of the basic pillars of modern cardiology. The potential list of scenarios where cardiac imaging techniques can provide relevant information is simply endless so it is impossible to include all relevant new features of cardiac imaging published in the literature in 2012 in the limited format of a single article. We summarize the year's most relevant news on cardiac imaging, highlighting the ongoing development of myocardial deformation and 3-dimensional echocardiography techniques and the increasing use of magnetic resonance imaging and computed tomography in daily clinical practice.

Serial measurements of high-sensitivity cardiac troponin T after exercise stress test in stable coronary artery disease

OBJECTIVE

The aim was to assess serial measurements of high-sensitivity cardiac troponin T (hs-cTNT) post-exercise in patients with stable coronary artery disease (CAD).

METHODS

Twelve patients with positive coronary angiograms (CAD positives) and 12 controls performed an exercise stress test.

RESULTS

CAD positive had higher baseline and peak concentrations of hs-cTNT than controls. Significant increases in hs-cTNT were seen in both groups after exercise. In two-third of patients the peak in hs-cTNT was above the 99th percentile.

CONCLUSION

hs-cTNT is higher in patients with stable coronary disease than in controls and exceeds the diagnostic cut-off value for myocardial infarction in a majority of patients with CAD after exercise.