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

Abstract

Introduction: Takotsubo cardiomyopathy (TCM) is a life-threatening systemic consequence early after subarachnoid hemorrhage (SAH), but precise hemodynamics and related outcome have not been studied. The purpose of this study was to investigate the 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 cardiac function index (CFI) was significantly correlated with (LVEF) (r = 0.82, P < 0.0001). The CFI between day 0 to day 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 of < 4.2 min-1 had a sensitivity of 82% and specificity of 84% for detecting LVEF <40%. The CFI < 4.2 min-1 was associated with delayed cerebral ischemia (DCI) (odds ratio (OR), 2.14; 95% confidence interval (CI), 1.33-2.86; P = 0.004) and poor 3-month functional outcome on modified Rankin Scale of 4-6 (OR, 1.87; 95% CI, 1.06-3.29; P = 0.02). An extravascular lung water index (ELWI) > 14 mL/kg after day 4 increased the risk of poor functional outcome at 3-month follow-up (OR, 2.10; 95% CI, 1.11-3.97; P = 0.04).

Conclusions: Prolonged cardiac dysfunction and pulmonary edema increased the risk of DCI and poor 3-month functional outcome in patients with SAH suffering from TCM. Serial measurements of CFI and ELWI by transpulmonary thermodilution may provide an easy bedside method of detecting early changes of the cardiopulmonary function in directing proper post-SAH treatment.

Figure 1

Changes in hemodynamic parameters over 14 days in 46 subarachnoid hemorrhage patients with Takotsubo cardiomyopathy. Cardiac function index (CFI) (A), cardiac index (CI) (B), global end-diastolic volume index (GEDI) (C) and extravascular lung water index (ELWI) (D) in patients with (●) or without (○) left ventricular (LV) dysfunction. Data were obtained from a total of 1,330 PiCCO™ measurements. Averaged data collected every 12 hours (twice a day) are presented. *P < 0.05 for left ventricular ejection fraction (LVEF) ≥40% versus LVEF <40% at the same time point. SAH: Subarachnoid hemorrhage.

Figure 2

Relationship between cardiac function index and left ventricular ejection fraction in 46 subarachnoid hemorrhage patients with Takotsubo cardiomyopathy. (A) Three-dimensional regression data plot showing the relationship between cardiac function index (CFI) and left ventricular ejection fraction (LVEF) and time duration (days after subarachnoid hemorrhage (SAH) onset). Correlation between CFI and LVEF was analyzed by mixed-effects logistic regression (among subjects, groups, time duration). (B) Receiver operating characteristic curves constructed based on the sensitivity and specificity of the CFI for identifying LVEF <40%. Data were obtained from a simultaneous measurement of CFI and LVEF using the PiCCO™ device and echocardiograms, respectively (N = 870 data pairs).

Figure 3

Changes in cardiac function index during volume expansion and hyperdynamic therapy for delayed cerebral ischemia–related neurological deterioration in 25 subarachnoid hemorrhage patients with Takotsubo cardiomyopathy. Graph shows changes in cardiac index (CI), global end-diastolic volume index (GEDI) and cardiac function index (CFI) during volume expansion with 500 ml of 6% hydroxyethyl starch (HES) (n = 112) or hyperdynamic therapy with dobutamine (DOB) (n = 55). Data were collected before and after each challenge (a 500 ml infusion of HES or an incremental infusion (3 μg/kg/min) of DOB, sampled in situations without coadministration) between days 4 and 14. *P < 0.05, **P < 0.01 compared with baseline before each challenge (% change).