Validation of proposed risk stratification system for in‐hospital cardiac complications in patients with takotsubo syndrome

We read with great interest a position statement on takotsubo syndrome (TS) by Lyon et al. in a recent issue of the journal. They propose the newly risk stratification system for in-hospital cardiac complications in patients with TS. However, it is based on expert opinions, and there is no validation in the clinical setting. We validated the risk stratification system in our TS database (n = 154). In-hospital cardiac complications were defined as cardiogenic shock, pulmonary oedema, ventricular tachycardia/ventricular fibrillation, complete atrioventricular block, thromboembolism, cardiac rupture, and cardiac death. In-hospital cardiac complications were observed in 61 patients (40%). There were 25 patients with cardiogenic shock (16%) and 44 patients with pulmonary oedema (29%). Ventricular tachycardia/ventricular fibrillation, complete atrioventricular block and thromboembolism were observed in 10 (7%) and 4 patients (3%), respectively. Four cardiac deaths (3%) were observed. Of these, one patient died of cardiac rupture. According to the risk stratification system, 135 patients (88%) were at high risk and only 19 patients (12%) were at low risk. Cardiac complications occurred in 45% of patients in high risk and no cardiac complication in patients at low risk (P< 0.01). As just described, the risk stratification system for cardiac complications of TS categorizes most of the patients into the high-risk group. Therefore, we assigned 2 points for each major risk factor and 1 point for each minor risk factor and calculated the total points. They were classified into four groups according to the points: group I 0–2, group II 3–5, group III 6–8, and group IV >9. Based on our scoring system, 41 (27%), 65 (42%), 33 (21%), and 15 patients (10%) were classified as groups I, II, III, and IV, respectively. Cardiac complications were observed in 5, 35, 70, and 87% of the patients in each group (Figure 1, P< 0.01). In conclusion, the risk stratification system for cardiac complications of TS is useful but categorizes most of the patients into the high-risk group. Our proposed scoring system may be more useful to predict in-hospital cardiac complications in patients with TS. Ken Kato Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, Chiba, Japan E-mail: [email protected]