Dynamic left intraventricular obstruction in patients with septic shock: pathogenetic role and prognostic implications

Abstract

Background Left intraventricular flow obstruction (IVO) has been classically described in asymmetric hypertrophic cardiomyopathy, usually at the level of the left ventricular outflow tract (LVOT) or at midcavitary level, which is due to systolic anterior movement of the anterior leaflet of the mitral valve. This phenomenon has also been previously described in certain clinical situations mainly revolving around hypovolemia and catecholamine exposure and recently as a frequent event in patients with septic shock with an important correlation with fluid responsiveness. Multiple studies have demonstrated that static parameters limited the predictive value for fluid responsiveness, whereas dynamic parameters have shown a greater clinical use, including respiratory changes in aortic blood velocity, superior vena cava collapsibility, inferior vena cava (IVC) collapsibility, and changes in stroke volume and Cardiac Output (CO) owing to passive leg raising. Objective This study aimed to assess (a) the prevalence of dynamic IVO in patients with septic shock; (b) relation among IVO, volume status, and fluid responsiveness; and (c) relation between IVO and in-hospital mortality. Patients and methods A total of 40 patients with septic shock were studied over a period of 1 year for the presence of Doppler signs of dynamic IVO, clinical characteristics, hemodynamic parameters, and APACHE II and SOFA scoring. Echocardiographic data including IVC collapsibility, CO, LVOT mean and peak pressure gradient, LVOT maximum velocity, and midcavitary Doppler pattern were recorded initially and following fluid resuscitation (30 ml/kg). Patients were categorized into two groups: group A included patients with IVO and group B included patients without IVO. There was a statistically nonsignificant difference between both groups regarding the baseline demographic, clinical, and hemodynamic parameters. Results A total of 40 (45% were males and 55% females) patients, with a mean age of 52±20 years, were studied, of whom a total of 13 (32%) had IVO versus 27 patients without IVO. Following fluid infusion, as compared with group B, group A showed significantly greater increase in Cardiac Output (COP) (5.85±1.4 vs. 4.4±1.8, P=0.0203) and IVC collapsibility (54.42±6.8 vs 50.56±13, P=0.42). ICU mortality was significantly higher in patients with IVO [10/13 (76.9%)] versus patients without IVO [7/27 (25.9%), P Conclusion Dynamic left IVO is not uncommon in patients with septic shock in ICU. Response to fluid infusion was significantly higher in patients with IVO compared with patients without IVO, pointing to an additional role of fluid resuscitation in patients with sepsis.