Early dynamic left intraventricular obstruction is associated with hypovolemia and high mortality in septic shock patients

Abstract

Introduction: Based on previously published case reports demonstrating dynamic left intraventricular obstruction (IVO) triggered by hypovolemia or catecholamines, this study aimed to establish: (1) IVO occurrence in septic shock patients; (2) correlation between the intraventricular gradient and volume status and fluid responsiveness; and (3) mortality rate.

Method: We prospectively analyzed patients with septic shock admitted to a general ICU over a 28-month period who presented Doppler signs of IVO. Clinical characteristics and hemodynamic parameters as well as echocardiographic data regarding left ventricular function, size, and calculated mass, and left ventricular outflow Doppler pattern and velocity before and after fluid infusions were recorded.

Results: During the study period, 218 patients with septic shock were admitted to our ICU. IVO was observed in 47 (22%) patients. Mortality rate at 28 days was found to be higher in patients with than in patients without IVO (55% versus 33%, p < 0.01). Small, hypercontractile left ventricles (end-diastolic left ventricular surface 4.7 ± 2.1 cm(2)/m(2) and ejection fraction 82 ± 12%), and frequent pseudohypertrophy were found in these patients. A rise ≥12% in stroke index was found in 87% of patients with IVO, with a drop of 47% in IVO after fluid infusion.

Conclusion: Left IVO is a frequent event in septic shock patients with an important correlation with fluid responsiveness. The mortality rate was found to be higher in these patients in comparison with patients without obstruction.

Fig. 1

Flow chart. IVO intraventricular obstruction

Fig. 2

Left intraventricular obstruction. a Pulsed-wave Doppler curve showing the characteristic late peaking saber-shape indicating a LV outflow obstruction (IVG). b After fluid replacement, the flow profile returns to normal symmetrical shape

Fig. 3

Pseudohypertrophy. Echocardiography in the parasternal short axis view. Ventricular wall appear thickened in these two-dimensional images, despite LV mass being unchanged. a The reduction in LVEDD size of the left ventricle (LV). b The near obliteration of the ventricular lumen in systole (“kissing” walls)

Fig. 4

Pre- and postfluid bolus comparison. Comparison of intraventricular obstruction gradient before and after a single 500 ml fluid bolus; points correspond to mean values and error bars to two standard errors of the mean. The difference before and after volume expansion was statistically different (p = 0.001)