Prognostic Value of Myocardial Contrast Echocardiography in Patients Presenting to Hospital With Acute Chest Pain and Negative Troponin Paramjit Jeetley, MBBS, Leah Burden, BSc, Kim Greaves, MD, and Roxy Senior, MD* We hypothesized that myocardial contrast echocardiography (MCE) could be used to stratify risk in patients with suspected acute coronary syndrome but a nondiagnostic electrocardiogram and negative troponin. Pretest Thrombolysis In Myocardial Infarc- tion (TIMI) scores were determined. Exercise electrocardiographic data in those pa- tients undergoing treadmill stress echocardiography as part of risk evaluation were analyzed independently of echocardiographic data. On a separate day, low-power MCE at rest and during vasodilator stress was performed. All patients were followed for cardiac events (cardiac death, myocardial infarction, and revascularization). Of 148 patients, 27 demonstrated abnormal myocardial contrast echocardiographic results and had higher cardiac event rates compared with those with normal myocardial contrast echocardiographic findings (59% vs 7%, p <0.0001) at follow-up (8  5 months). Hard cardiac event rates (death and nonfatal myocardial infarction) were low (3%) in patients with normal myocardial contrast echocardiographic findings. Cardiac events in patients with abnormal myocardial contrast echocardiographic findings (59%) were significantly higher than those predicted by a high-risk TIMI score (33%, p  0.0023) and compared with those predicted by high-risk exercise electrocardiography (80% vs 57%, p  0.0003). In conclusion, stress MCE was superior to TIMI risk score and exercise electrocardiography in the assessment of risk in patients with suspected acute coronary syndrome, nondiagnostic electrocardiogram, and negative troponin. © 2007 Elsevier Inc. All rights reserved. (Am J Cardiol 2007;99:1369 –1373) Myocardial contrast echocardiography (MCE) is a relatively new technique that uses intravenously administered contrast microbubbles for the detection of myocardial perfusion. 1,2 Stress MCE has been shown to accurately detect flow- limiting coronary artery disease in a wide variety of clinical scenarios and is a powerful predictor of outcome in patients with suspected coronary artery disease. 3–7 Compared with other competing techniques, vasodilator MCE can be rap- idly performed and interpreted, and it can be carried out at bedside. However, there is no current study demonstrating its utility in patients with suspected acute coronary syn- drome but negative serum cardiac markers who would require stress testing for further risk stratification. We hy- pothesized that vasodilator MCE by its ability to detect flow-limiting coronary artery disease could effectively strat- ify risk in patients with suspected acute coronary syndrome and coronary risk factors but with a nondiagnostic electro- cardiogram and normal serum cardiac markers of necrosis. Methods Patient selection: Patients were selected from a popula- tion who had enrolled in a prospective study investigating risk stratification of patients presenting to the hospital with suspected acute coronary syndrome but with nondiagnostic electrocardiogram and negative troponin. Written informed consent was obtained from all patients, and the study was approved by the local ethics committee. Study design: The study design is shown in Figure 1.A pretest probability of risk was determined on the basis of individual Thrombolysis In Myocardial Infarction (TIMI) risk scores. 8 Patients were categorized as having a low (score 0 and 2), intermediate (score 2 to 4), or high (score 5) pretest risk. Patients underwent further risk stratifica- tion using stress echocardiography (SE) with treadmill ex- ercise or pharmacologic (dobutamine) stress using previ- ously described methods. 9 MCE was performed on a separate day. Results of SE were made available to clinical staff directly involved with patient care, which influenced subsequent management. Myocardial contrast echocardio- graphic data were not disclosed. Myocardial contrast echocardiography: MCE was performed in apical 4-, 3-, and 2-chamber views with trig- gered replenishment imaging (Sonos 5000, Phillips, Eind- hoven, The Netherlands). The contrast agent (SonoVue, Bracco Diagnostics, Inc., Milan, Italy) was administered through a peripheral cannula at a rate of 1 ml/min and adjusted as necessary until optimal myocardial contrast ac- Department of Cardiovascular Medicine, Northwick Park Hospital and Institute for Medical Education and Research, Harrow, Middlesex, United Kingdom. Manuscript received October 20, 2006; revised manuscript received and accepted December 28, 2006. The study was supported by a grant from Cardiac Research Fund, Northwick Park Hospital, Harrow, United Kingdom. *Corresponding author: Tel: 44-0-2088-692-547; fax: 44-0-2088-640- 075. E-mail address: roxysenior@cardiac-research.org (R. Senior). 0002-9149/07/$ – see front matter © 2007 Elsevier Inc. All rights reserved. www.AJConline.org doi:10.1016/j.amjcard.2006.12.062