Association between speckle tracking echocardiography and pressure-volume loops during cardiogenic shock development

The relationship between speckle tracking assessed global longitudinal strain (GLS) and Doppler-based echocardiography with basic physiological markers of cardiac function derived from pressure-volume loops is poorly elucidated.

We aimed to describe the association between LS and Doppler-based echocardiography and direct measurements of central haemodynamic parameters from conductance catheter-based pressure-volume loops in an animal model with increasing left ventricular (LV) dysfunction.

12 Danish landrace female pigs (75-80 kg) were used. All instrumentations were performed percutaneously, including the conductance catheter in the LV. Progressive LV dysfunction was induced by embolisation through the left main coronary artery with microspheres every 3 min until a >50% reduction in cardiac output (CO) or mixed venous saturation (SvO₂), compared with baseline, or SvO₂ <30%. Echocardiography was performed at baseline and 90 s after each injection.

With progressive LV dysfunction, mean CO decreased from 5.6±0.9 L/min to 2.1±0.9 L/min, and mean SvO₂ deteriorated from 61.1±7.9% to 35.3±6.1%. Mean LS and LV outflow tract velocity time integral (LVOT VTI) declined from -13.8±3.0% to -6.1±2.0% and 16.9±2.6 cm to 7.8±1.8 cm, respectively. LS and LVOT VTI showed the strongest correlation to stroke work in unadjusted linear regression (r²=0.53 and r²=0.49, respectively). LS correlated significantly with stroke volume, end-systolic elastance, systolic blood pressure, ventriculo-arterial coupling and arterial elastance.

In an animal model of acute progressive LV dysfunction, echocardiographic and conductance catheter-based measurements changed significantly. LS and LVOT VTI displayed the earliest and the largest alterations with increased myocardial damage and both correlated strongest with stroke work.