Myocardial Perfusion Imaging for Evaluation and Triage of Patients with Suspected Acute Cardiac Ischemia: A Randomized Controlled Trial. - Myocardial Perfusion Imaging for Evaluation and Triage of Patients with Suspected Acute Cardiac Ischemia: A Randomized Controlled Trial.

Description:

The goal of this study was to assess the safety and efficacy of resting myocardial perfusion imaging (MPI) (technetium Tc99m sestamibi) on outcomes in patients evaluated in an emergency department for chest pain.

Study Design

Study Design:

Patients Enrolled: 2475
Mean Follow Up: 24-36 hours and 30 day follow up

Patient Populations:

chest pain suggestive of myocardial ischemia and either a normal or non-diagnostic ECG

Drug/Procedures Used:

Patients (n = 2,475) presenting to 7 emergency departments (ED) with chest pain suggestive of myocardial ischemia and either a normal or non-diagnostic ECG were randomized to usual care (UC) or UC plus rest MPI. MPI results were available to the ED physician for decision making. Short-term (24 – 36 hours) and 30 day follow-up were available in 99% of patients who were subsequently characterized as having myocardial infarction (MI), acute cardiac ischemia (ACI) or non-coronary symptoms (NCS).

Principal Findings:

There was no difference in appropriate hospitalization for MI between the UC and MPI; one MI was discharged in each group. MPI resulted in 81% of patients with ACI being admitted compared to 83% of UC. At 30 days death, catheterization, and revascularization rates were statistically similar in the two groups. Addition of MPI resulted in direct discharge from the ED in 53% of patients v. 44% for UC. MI was present in 26 patients in the MPI group and in 30 in usual care; ACI was present in 139 in the MPI group and 134 in UC. 2146 patients had a final diagnosis of NCS. Of those in the UC group 52% were hospitalized v. 42% in the MPI group (p < 0.001).

Interpretation:

Among patients with MI or ACI, addition of MPI to ED decision making results in a reduced rate of hospitalization for patients whose eventual diagnosis is NCS without increasing the number of discharges. This large, multi-center randomized trial demonstrates that addition of rest MPI may reduce presumably unnecessary hospitalization rates by up to 20%, without increasing the risk of inappropriate discharge. It should be emphasized that the patient population evaluated excluded individuals with prior MI. Also excluded were individuals whose chest pain syndrome had resolved > 3 hours prior to presentation. While this study was conducted in high volume academic and urban centers, the studies were performed by nuclear medicine technicians and the type of analysis performed may be easily adaptable to telemedicine techniques. Not addressed in this study is the actual cost effectiveness of this approach which will of necessity be impacted by the prevalence of patients with active ischemia v. other etiologies for their acute presentation.

References:

Udelson JE, Beshansky, JR, Ballin DS, et al. Myocardial Perfusion Imaging for Evaluation and Triage of Patients with Suspected Acute Cardiac Ischemia: A Randomized Controlled Trial. JAMA 2002;288:2693-2700.

Clinical Topics: Noninvasive Imaging, Nuclear Imaging

Keywords: Myocardial Perfusion Imaging, Cost-Benefit Analysis, Myocardial Infarction, Follow-Up Studies, Decision Making, Technetium Tc 99m Sestamibi, Emergency Service, Hospital, Electrocardiography, Nuclear Medicine, Chest Pain, Telemedicine, Catheterization


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