Background: This study evaluated the usefulness of cardiac sympathetic nerve activity, estimated by (123)I-MIBG scintigraphy, and endothelial function, estimated by flow-mediated dilation (FMD), in the detection of coronary spastic angina (CSA).
Methods and results: We compared 78 consecutive patients suspected of CSA with ten age-matched controls. On the basis of a spasm provocation test with acetylcholine, 53 patients were diagnosed as CSA and 25 patients were considered to have chest-pain syndrome (CPS). The total defect score (TDS) by delayed (123)I-MIBG scintigraphy was significantly higher in both patient groups than in controls (P < 0.05), and was significantly higher in CSA than in CPS patients (P = 0.02). The heart/mediastinum activity (H/M) ratio by delayed (123)I-MIBG scintigraphy and FMD were significantly lower in both patient groups than in controls (P < 0.05), and were lower in CSA than in CPS patients (P = 0.04). In receiver-operating curve analysis, the areas under the curve for TDS, H/M, and FMD were 0.78, 0.72, and 0.70, respectively. The combination of delayed (123)I-MIBG scintigraphy and FMD showed a higher diagnostic value than either method alone.
Conclusions: (123)I-MIBG scintigraphy and FMD can distinguish CSA patients among patients complaining of chest pain at rest, with good sensitivity and specificity.