Characteristics of coronary microcirculatory function in patients with Takotsubo syndrome

Background: Takotsubo syndrome (TS) is a recently described cardiac syndrome whose pathogenesis is still unclear. We investigated the characteristics of coronary microcirculatory function in patients with TS through the analysis of the TIMI frame count (TFC) compared to normal subjects and with to subjects with microvascular angina (MA). Methods: We enrolled 71 TS patients (F:M =69:2, mean age of 65.27±9.53 years), 70 controls (F:M =34:36, mean age of 56.63±13.5 years) and 71 patients with MA, (F:M =69:2, mean age of 65.9±9.2 years). The assessment of the microcirculation was carried out through the TFC. Results: microcirculation was significantly altered in patients with TS compared with healthy controls [left anterior descending coronary artery (LAD) 25.16±6.91 vs. 17.30±3.76, P<0.001; circumflex artery (CX) 25.48±6.10 vs. 17.05±4.60, P<0.001; right coronary artery (RCA) 26.43±8.95 vs. 15.74±4.27, P<0.001, average TFC in TS 25.70±5.34 vs. 16,70±3.26, P<0.001). A TFC >20 frames was able to discriminate TS patients from controls with a specificity of 88.57% and sensitivity of 85.92% (AUC 0.927, P<0.0001). Microvascular dysfunction was diffuse in TS as well as in MA and slightly more severe in this last (mean TFC in MA 28.25±9.3 vs. 25.7±5.34 in TS, P<0.046). Conclusions: Coronary microcirculation in TS patients is diffuse and milder compared to MA patients. Cut-off values >20 frames discriminate between patients with normal microcirculation and patients with TS.