Does dobutamine stress echocardiography induce damage during viability diagnosis of patients with chronic regional dysfunction after myocardial infarction?

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.

Comparison of the Effects of Levosimendan Dobutamine and Vasodilator Therapy on Ongoing Myocardial Injury in Acute Decompensated Heart Failure

BACKGROUND

Cardiac troponins (cTn) are reliable and the most sensitive biomarker in the setting of acute decompensated heart failure (ADHF). Acute decompensated heart failure is usually associated with worsening chronic heart failure, and it may be caused by ongoing minor myocardial cell damage that may occur without any reported precipitating factors.

METHODS

We compared the short-term effect of levosimendan (LEV), dobutamine (DOB), and vasodilator treatment (nitroglycerin [NTG]) on myocardial injury with hemodynamic, neurohumoral, and inflammatory indicators. One hundred twenty-two patients with a mean age of 66 ± 9 years were treated with LEV (n = 40), DOB (n = 42), and NTG (n = 40) and examined retrospectively. Blood samples (cTnI, N-terminal probrain natriuretic peptide [NT-proBNP], highly sensitive C-reactive protein [HsCRP], and others), left ventricular ejection fraction (LVEF), systolic pulmonary artery pressure (sPAP), and 6-minute walk distance (6MWD) were compared before and after treatment.

RESULTS

At admission, detectable levels of cTnI were observed in 53% of patients (≥0.05 ng/mL). Serial changes in the mean cTnI levels were not significantly different between the groups (LEV 0.04 ± 0.01 to 0.03 ± 0.01 ng/mL; DOB 0.145 ± 0.08 to 0.08 ± 0.03 ng/mL; NTG 0.1 ± 0.03 to 0.09 ± 0.02 ng/mL; overall P = .859). Favourable effects on the NT-proBNP, sPAP values, LVEF, 6MWD, and HsCRP were observed overall, especially in the LEV groups.

CONCLUSION

Beneficial effects of short-term use of LEV, DOB, and NTG on ongoing myocardial injury were demonstrated. These findings can be attributed to the anti-ischemic properties as well as the hemodynamic, neurohumoral, and functional benefits from the positive inotropes, especially LEV, in patients with ADHF.

[Dobutamine stress echocardiography and troponin T as a marker of myocardial injury]

Introduction and objectives. Troponin T (TnT) is a very specific marker of myocardial damage. Our objective was to describe TnT behavior after dobutamine stress echocardiography (EDOB) and evaluate its usefulness for improving the diagnostic power of EDOB.Methods. Blood levels of TnT were measured at baseline and 3, 6, 12, and 24 h after EDOB in 63 patients (mean age: 69 9; 38 males). Coronary angiography was performed on 36 patients.Results. EDOB was positive in 29 patients and there was an increase over baseline values in 15 of them (51%); EDOB was negative in 34 patients and there was only a rise in TnT in 7 (20%; p < 0.01). The TnT increment was higher in patients with a positive response to EDOB (0.033 0.02 vs. 0.026 0.01; p < 0.01). The ischemia score index was higher in patients in which a significant increase in TnT values was later detected (0.41 0.31 vs. 0.38 0.20; p < 0.01). Coronariography was performed in 36 patients. EDOB was positive in 22 of the 29 patients with coronary artery disease (76%) and TnT was raised in 14 of them (48%; p < 0.05).Conclusion. The rise in TnT levels during EDOB suggests that this test may produce myocardial damage associated with the appearance of contractility disorders during dobutamine infusion.

Echocardiography, nuclear scintigraphy, and stress testing in the emergency department evaluation of acute coronary syndrome

There are between 3 and 5 million visits to EDs each year for complaints of chest pain. Of these, about one half of the patients have a noncardiac cause for their chest pain. Of the remainder, about 30% to 50% have significant coronary disease. It is quite clear that patients who are at high risk for a coronary event should be admitted to the hospital. For the low-to-moderate risk patients, the decision to admit or discharge the patient from the ED is not quite so easy. The emergency physician has to decide which tests can be helpful in the decision-making process, this can be undertaken in conjunction with a consultative cardiologist. It can be argued that if a patient does not have a normal test result whichever that evaluatory test is), then the patient should be admitted for further work-up and evaluation. The easiest test to perform in the ED setting is an echocardiogram. The images can be sent by telecommunication to a qualified echocardiogram reader for interpretation. This also has a reasonable NPV, although not necessarily as good as some of the other modalities available, unless interpreted in light of cardiac enzyme test results. If the index of suspicion is still high, then a stress echocardiogram can be considered. This has an excellent NPV and can be easily performed in [table: see text] most patients. This should not be undertaken in the face of an evolving MI, and patients should be observed for at least 8 hours after their initial presentation to the ED prior to undergoing a provocative test. Nuclear scintigraphy, another modality available for cardiac risk stratification, can be a logistical nightmare. The nuclear isotopes are strictly regulated by the Nuclear Regulatory Commission. The emergency physician may inject the isotopes, provided that he or she has undergone the necessary radiation training. Also, the patient must be removed from the ED to a radioisotope-approved area for the duration of the scan. One of the most difficult questions left open after review of all these analytical modalities is the duration of time these test results remain valid; when does an individual patient need to be reevaluated as to their specific pretest probability? The answer to this question lies in the presenting clinical scenario. If the patient presents with a similar inciting trigger for his or her symptoms, and the cardiac risk profile has not changed appreciably, then the previous study (whether a provocative stress test or even a cardiac catheterization) probably can be reliably counted. If the patient's risk profile has changed or the symptoms are new or more intense, the physician is compelled to pursue this encounter as a new, acute event. This can be true even in the setting of a previous cardiac catheterization that showed nonobstructive coronary disease, because plaque rupture can be acute and unpredictable. Ultimately, optimal care calls for each institution to develop a specific approach, in conjunction with their consultative cardiologist or critical care specialist, to enhance patient care, safety, and diagnostic outcome, while maintaining cost efficiency.