[Usefulness of technetium-99m tetrofosmin single-photon emission computed tomography for short-term risk stratification in patients with acute chest pain in the emergency room].

Objectives: High-risk patients with acute coronary syndrome are difficult to distinguish from low-risk patients with chest pain in the emergency room. Technetium-99m (99mTc) tetrofosmin single-photon emission computed tomography (SPECT) was investigated to exclude high-risk patients with chest pain in the emergency room.

Methods: 99mTc-tetrofosmin SPECT was evaluated using a four-point scoring system in 228 patients (144 men, 84 women, mean age 68 +/- 12 years) with chest pain. Negative was defined as the myocardial segments with a defect score (DS) of < 2. The patients were divided into two groups; the negative group with DS < 2 (n = 78) and the positive group with DS > or = 2 (n = 150). Cardiac events (cardiac death, acute myocardial infarction and refractory angina) were evaluated within 30 days of onset. ST-segment elevation or depression > or = 0.1 mV was defined as positive in electrocardiography. The results of SPECT were compared with those of electrocardiography, transthoracic echocardiography and serum cardiac markers (troponin T and creatine kinase-MB) in 95 patients.

Results: The negative group had very few cardiac events (three patients with refractory angina) (3.8%). The negative predictive value of cardiac events evaluated by electrocardiography was calculated as 83.1%, whereas the negative predictive value by SPECT was 96.2% (p < 0.01). In addition, the negative predictive value of acute myocardial infarction by SPECT was 100%. The negative predictive values of cardiac events evaluated by SPECT, electrocardiography, transthoracic echocardiography and serum cardiac markers were 95.8%, 81.5% (vs 99mTc-tetrofosmin; NS), 84.9% (NS) and 60.4% (p < 0.05), respectively.

Conclusions: 99mTc-tetrofosmin SPECT is a useful method to exclude high-risk patients among patients with chest pain in the emergency room.