Negative predictive value and potential cost savings of acute nuclear myocardial perfusion imaging in low risk patients with suspected acute coronary syndrome: A prospective single blinded study

We included 40 patients (mean age 55 ± 2 years, 50% women) who were admitted from the ED at Lund University Hospital for chest pain suspicious of ACS, and who had a normal or non-ischemic ECG and no previous myocardial infarction. All patients underwent MPI from the ED, and the results were analyzed only after patient discharge. The current diagnostic practice of admitting the included patients for observation and further evaluation was compared to a theoretical "MPI strategy", where patients with a normal MPI test would have been discharged home from the ED.Twenty-seven patients had normal MPI results, and none of them had ACS. MPI thus had a negative predictive value for ACS of 100%. With the MPI strategy, 2/3 of the patients would thus have been discharged from the ED, resulting in a reduction of total hospital cost by some 270 EUR and of bed occupancy by 0.8 days per investigated patient.Our findings in a Swedish ED support the results of larger American trials that acute MPI has the potential to safely reduce the number of admissions and decrease overall costs for low-risk ED patients with suspected ACS.It has been estimated that some 180000 patients with chest pain suspicious of ACS (= acute myocardial infarction, AMI, or unstable angina pectoris) present at Swedish emergency departments (EDs) each year [1,2]. Current diagnostic methods for ACS in the ED, however, are clearly suboptimal. As a result, "rule-out" admissions are very common, and 7 out of 10 patients admitted for suspected ACS prove not to have it [1,3]. Also, many cases of ACS are diagnosed only after lengthy observation, with a resulting delay in therapy and an impaired prognosis. As many as 2–5% of those with ACS are erroneously sent home from the ED [4,5].To overcome these problems, several new diagnostic methods have been suggested [6], e.g. echocardiography [7], multidetector CT scanning [8] and nuclear myocardial perfusion imaging (MPI) [9]. Acute MPI has been shown to be of value in routin