Impact of transpulmonary thermodilution-based cardiac contractility and extravascular lung water measurements on clinical outcome of patients with Takotsubo cardiomyopathy after subarachnoid hemorrhage: A retrospective observational study

Introduction: Takotsubo cardiomyopathy (TCM) is a life-threatening systemic consequence early after subarachnoid hemorrhage (SAH), but precise hemodynamics and related outcomes have not been studied. The purpose of this study was to investigate TCM-induced cardiac function by transpulmonary thermodilution and its impact on clinical outcome of SAH. Methods: We retrospectively analyzed 46 consecutive postoperative SAH patients who developed TCM. Patients were divided into two groups of echocardiographic left ventricular ejection fraction (LVEF) <40% (TCM with left ventricular (LV) dysfunction) and LVEF ≥40% (TCM without LV dysfunction). Cardiac function index (CFI) and extravascular lung water index (ELWI) were monitored by transpulmonary thermodilution in parallel with serial measurements of echocardiographic parameters and blood biochemical markers. Results: Transpulmonary thermodilution-derived CFI was significantly correlated with LVEF (r = 0.82, P < 0.0001). The CFI between days 0 and 7 was significantly lower in patients with LV dysfunction (LVEF <40%) than in patients with LVEF ≥40% (P < 0.05). CFI had a better ability than cardiac output to detect cardiac dysfunction (LVEF <40%) (area under the curve = 0.85 ± 0.02; P < 0.001). A CFI value <4.2min^-1 had a sensitivity of 82% and specificity of 84% for detecting LVEF <40%. CFI <4.2min^-1 was associated with delayed cerebral ischemia (DCI) (odds ratio (OR) = 2.14, 95% confidence interval (CI) = 1.33 to 2.86; P = 0.004) and poor 3-month functional outcome on a modified Rankin Scale of 4 to 6 (OR = 1.87, 95% CI = 1.06 to 3.29; P = 0.02). An extravascular lung water index (ELWI) >14ml/kg after day 4 increased the risk of poor functional outcome at 3-month follow-up (OR = 2.10, 95% CI = 1.11 to 3.97; P = 0.04). Conclusions: Prolonged cardiac dysfunction and pulmonary edema increased the risk of DCI and poor 3-month functional outcome in postoperative SAH patients with TCM. Serial measurements of CFI and ELWI by transpulmonary thermodilution may provide an easy bedside method of detecting early changes in cardiopulmonary function to direct proper post-SAH treatment.