The prognostic value of left ventricular systolic function measured by tissue Doppler imaging in septic shock

Abstract

Introduction: Left ventricular (LV) dysfunction is common in septic shock. Its association with the clinical outcome is still controversial. Tissue Doppler imaging (TDI) is a useful tool to quantify LV function; however, little knowledge is available about the prognostic value of these TDI variables in septic shock. Therefore, we performed this prospective study to determine the role of TDI variables in septic shock.

Methods: Patients with septic shock in a medical intensive care unit were studied with transthoracic echocardiography with TDI within 24 hours after the onset of septic shock. Baseline clinical, laboratory, and echocardiographic variables were prospectively collected. Independent predictors of 90-day mortality were analyzed with the Cox regression model.

Results: During a 20-month period, 61 patients were enrolled in the study. The 90-day mortality rate was 39%; the mean APACHE IV score was 84 (68 to 97). Compared with survivors, nonsurvivors exhibited significantly higher peak systolic velocity measured at the mitral annulus (Sa) (11.0 (9.1 to 12.5) versus 7.8 (5.5 to 9.0) cm/sec; P < 0.0001), lower PaO2/FiO2 (123 (83 to 187) versus 186 (142 to 269) mm Hg; P = 0.002], higher heart rate (120 (90 to 140) versus 103 (90 to 114) beats/min; P = 0.004], and a higher dose of norepinephrine (0.6 (0.2 to 1.0) versus 0.3 (0.2 to 0.5) μg/kg/min; P = 0.007]. In the multivariate analysis, Sa > 9 cm/sec (hazard ratio (HR), 5.559; 95% confidence interval (CI), 2.160 to 14.305; P < 0.0001), dose of norepinephrine (HR, 1.964; 95% CI, 1.338 to 2.883; P = 0.001), and PaO2/FiO2 (HR, 0.992; 95% CI, 0.984 to 0.999; P = 0.031) remain independent predictors of 90-day mortality in septic-shock patients.

Conclusions: Our study demonstrated that LV systolic function as determined by TDI, in particular, Sa, might be associated with mortality in patients with septic shock.

Figure 1

The line regression between left ventricular ejection fraction (LVEF) and mitral annulus (Sa).

Figure 2

Receiver-operating characteristic (ROC) curve for predicting 90-day mortality by using the peak systolic velocity measured at the mitral annulus (Sa). Area under the curve is 0.83.

Figure 3

The 90-day mortality in the study population classified according to the peak systolic velocity measured at mitral annulus (Sa) < 9 cm/sec or Sa > 9 cm/sec.