Takotsubo Cardiomyopathy in a Swedish mixed ICU-population. A two year follow up of prevalence and short-term outcome.

Abstract

Master thesis, Programme in medicine TITLE: Takotsubo Cardiomyopathy in a Swedish mixed ICU-population. A two year follow up of prevalence and short-term outcome. Background: A new form of heart failure has recently been described in cardiology, Takotsubo or Stress-induced Cardiomyopathy (TCM). This cardiomyopathy is characterized by a transient, regional myocardial stunning (hypo/akinesis), usually involving the apical parts of the heart. This results in an apical ballooning of the heart with a characteristic shape when visualized. It is often associated with emotional or physical stress. The pathogenesis of this condition is not yet fully known. The current leading hypothesis involves an excess of catecholamines that triggers this regional myocardial stunning. Few studies have been published on TCM in the ICU setting. Aim: To estimate the prevalence of TCM in a mixed Intensive Care Unit (ICU) population. Further, to describe possible predisposing factors associated with TCM in the ICU, and evaluate if TCM affects ICU outcome. Methods: This is a retrospective systematic registry study on patients admitted to the ICU at Sahlgrenska University Hospital from January 2011 to December 2012. Electronic health records were accessed through various register programs, such as IVARätt, Melior and LabBest. 3885 patients were included in the study. Every echocardiogram done on patients admitted to the ICU in these two years (n=646) was used as an entry point to find patients with regional hypokinesis. Multivariate analysis was done, in order to find possible predisposing factors, and variables associated with mortality. Results: 2,1 % of the patients admitted to the ICU during the period from January 2011 to December 2012 were identified with TCM (n=80). Mean age was 63 ± 17 years, with a predominance for women. Parameters significantly associated with TCM were female sex, age, PaO2/FiO2 ratio < 200 and pH < 7,25. The mortality in the TCM patient population was 36,0 %, as compared to 31,2 % in the general ICU population. TCM and EF < 50 % were associated with increased ICU mortality, even when adjusted for severity of disease. Only EF < 50 % was associated with an increased 90 days mortality. Conclusions: The prevalence of TCM at Sahlgrenska University Hospital in 2011 and 2012 was 2,1 %. Female sex, age > 60 years, PaO2/FiO2 ratio < 200 and pH < 7,25 were identified as plausible predictors. Further studies would be favoured, to find out more precisely, how these factors are related to TCM. The finding of TCM associated with increased ICU mortality further emphasizes the importance of future research on this subject. Key Words: Takotsubo Cardiomyopathy, Stress-induced Cardiomyopathy, Intensive Care Unit (ICU)