Abstract Body (Do not enter title and authors here): Introduction: Septic shock is a common and often lethal disease. Myocardial dysfunction is a frequent complication in patients with septic shock. Common methods of assessing cardiac function, including left ventricular ejection fraction, are typically dependent on loading conditions, which may complicate interpretation. Left ventricular stroke work index (LVSWI), which incorporates LV preload and afterload, has been associated with adverse outcomes in several populations of chronic heart disease and in the cardiac intensive care unit (ICU). Given the known challenges with imaging critically ill patients, speckle tracking analysis may allow for calculation of stroke volume in patients where imaging may be limited.
Research Question: Is LVSWI from speckle tracking associated with mortality in sepsis and septic shock?
Methods: This is a secondary analysis of a prospectively studied cohort of patients admitted to one of two intensive care units with sepsis or septic shock. We performed transthoracic echocardiography on these patients within the first 24 hours of ICU admission. We used TomTec Image Arena to calculate stroke volume from an apical 4 chamber view. We calculated LVSWI as 0.0136 * (Stroke Volume / body surface area)*(mean arterial pressure – (1.9 + 1.24*E/e’)). We performed logistic regression for 28-day mortality, adjusting for Acute Physiology and Chronic Health Evaluation (APACHE II) score and receipt of vasopressors and mechanical ventilation.
Results: We studied 398 patients, 35% of whom received vasopressors, and 26% of whom were mechanically ventilated. Average APACHE II score was 26 ± 10 points, with a 23% mortality. Stroke volume by speckle tracking was measured in 343 patients (86.2%) compared to 230 patients with conventional stroke volume by Doppler. LVSWI averaged 3.0 ± 1.7 Dg min/m². Survivors had higher LVSWI than nonsurvivors (3.1 vs 2.5 Dg min/m², p = 0.01). On univariable analysis, LVSWI was associated with 28-day mortality (OR 0.79, 95% CI 0.65-0.96, p 0.02). This association persisted after adjusting for APACHE II and receipt of vasopressor and mechanical ventilation (OR 0.74, 95%CI 0.59-0.93, p < 0.01)
Conclusion: LVSWI from speckle tracking is associated with mortality in patients with sepsis and septic shock. LVSWI may be a useful clinical measurement in critically ill septic patients