Short- and Long-Term Prognostic Relevance of Cardiogenic Shock in Takotsubo Syndrome: Results From the RETAKO Registry.

OBJECTIVES: This study sought to describe the incidence, determinants, and prognostic impact of cardiogenic shock (CS) in takotsubo syndrome (TTS).

BACKGROUND: TTS can be associated with severe hemodynamic instability. The prognostic implication of CS has not been well characterized in large studies of TTS.

METHODS: We analyzed patients with a definitive TTS diagnosis (modified Mayo criteria) who were recruited for the National RETAKO (Registry on Takotsubo Syndrome) trial from 2003 to 2016. Cox and competing risk regression models were used to identify factors associated with mortality and recurrences.

RESULTS: A total of 711 patients were included, 81 (11.4%) of whom developed CS. Male sex, QTc interval prolongation, lower left ventricular ejection fraction at admission, physical triggers, and presence of "a significant" left intraventricular pressure gradient, were associated with CS (C index = 0.85). In-hospital complication rates, including mortality, were significantly higher in patients with CS. Over a median follow-up of 284 days (interquartile range: 94 to 929 days), CS was the strongest independent predictor of long-term, all-cause mortality (hazard ratio [HR]: 5.38; 95% confidence interval [CI]: 2.60 to 8.38); cardiovascular (CV) death (sub-HR: 4.29; 95% CI: 2.40 to 21.2), and non-CV death (sub-HR: 3.34; 95% CI: 1.70 to 6.53), whereas no significant difference in the recurrence rate was observed between groups (sub-HR: 0.76; 95% CI: 0.10 to 5.95). Among patients with CS, those who received beta-blockers at hospital discharge experienced lower 1-year mortality compared with those who did not receive a beta-blocker (HR: 0.52; 95% CI: 0.44 to 0.79; pinteraction  = 0.043).

CONCLUSIONS: CS is not uncommon and is associated with worse short- and long-term prognosis in TTS. CS complicating TTS may constitute a marker of underlying disease severity and could identify a masked heart failure phenotype with increased vulnerability to catecholamine-mediated myocardial stunning.